Patent Publication Number: US-11642710-B2

Title: Roll press machine, controlling system of roll press machine, and controlling method of roll press machine

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a 371 application of PCT/JP2019/008218 having an international filing date of Mar. 1, 2019, which claims priority to JP2018-061399 filed Mar. 28, 2018, the entire content of each of which is incorporated herein by reference. 
     TECHNICAL FIELD 
     The present invention pertains to a roll press machine, a controlling system of a roll press machine, and a controlling method of a roll press machine. 
     BACKGROUND ART 
     A roll press machine including a pair of lifting apparatuses has been conventionally known. For example, a forming-roll gap adjusting mechanism including a pair of lifting apparatuses has been disclosed in Patent Document 1. In addition, a pass line adjusting equipment including a pair of lifting apparatuses has been disclosed in Patent Document 2. 
       FIG.  18    corresponds to FIG. 1 of Patent Document 1. In the forming-roll gap adjusting mechanism shown in  FIG.  18   , each lifting apparatus uses an adjustment piece  312  having a wedged surface  313  to cause a bearing housing  306  having a tapered surface  311  to move up and down. A feed screw mechanism  315  is provided as a mechanism to cause the wedged surface  313  of the adjustment piece  312  to slidably move relative to the tapered surface  311  of the bearing housing  306 . 
       FIG.  19    corresponds to FIG. 3 of Patent Document 2. A wedge member  402  having a sloped surface  407   a  is used to move up and down with respect to a housing  408  having a sloped surface  408   a . A hydraulic cylinder  404  is provided as a mechanism to cause the sloped surface  407   a  of the wedge member  402  to slidably move relative to the sloped surface  408   a  of the housing  408 . 
     Herein, as a work of a roll press machine, the present inventors have particularly studied a metal foil after an electrode material has been applied thereon, which is usable for a rechargeable battery. 
     In detail, a paste electrode material is applied and baked on a metal foil capable of functioning as a current collector. Then, one electrode layer is formed. By repeating this process, a plurality of electrode layers are formed sequentially. For example, a copper foil intended to function as a cathode is used as a base material, and a cathode layer, a solid electrolyte layer and an anode layer are formed thereon in this order. 
     In general, the metal foil is continuously fed out from a rolled state. On the other hand, in general, the electrode layers are intermittently applied on the metal foil at even intervals (with gaps). 
     In a material in which a plurality of electrode layers having been baked on a metal foil as described above, there are spaces between the applied and baked electrode layers as well as there are spaces inside the respective electrode layers. That is to say, adhesiveness between particles (elements) of the raw material is low. This means that migration pathway is narrow for ions serving as a charge carrier. Thus, conductivity is low, which means that performance as a battery is not sufficient. 
     To the contrary, it is conceivable that, if it is possible to remove or reduce the spaces between the electrode layers as well as the spaces in the respective electrode layers, it is possible to enhance the adhesiveness between the particles (elements) of the raw material and thus it is possible to enhance the performance as a battery. Taking this into consideration, it has been studied to carry out a press-forming to a material in which a plurality of electrode layers having been baked on a metal foil. 
     PRIOR ART DOCUMENT 
     Patent Document List 
     
         
         Patent Document 1 is JP-A-H05-169117. 
         Patent Document 2 is JP-A-H07-265919. 
       
    
     SUMMARY OF INVENTION 
     Technical Problem 
     The present inventors have found that, by maintaining uniform thickness precision of a press-formed work with high precision, it is possible to effectively remove or reduce the spaces between the electrode layers as well as the spaces in the respective electrode layers. 
     If the thickness precision of a press-formed work is higher, the problem that thickness variation may cause an undesired gap at a subsequent assembling step to deteriorate the performance as a battery is inhibited. 
     Under the circumstances, the present inventors have studied and studied to develop a roll press machine capable of maintaining uniform thickness precision of a press-formed work with high precision. 
     Then, the present inventors have found that it is possible to control an operation of a roll press machine with high precision by adopting a moving apparatus which uses a rotational force of an electric motor. 
     Furthermore, the present inventors have found that, at a press-forming for a material in which a plurality of electrode layers having been baked on a metal foil, when the material is supplied as a work W into a gap between a lower roll and an upper roll for consolidating, a concentrated load may be generated at a front edge of the work, and also when the material is moved out of the gap, a concentrated load may be generated at a rear edge of the work. In those cases, chipping or crackling may be caused at the material (at the front and/or rear edges of the material). Then, the present inventors have found that, by finely controlling a moving apparatus using an electric motor, it is possible to prevent generation of such a concentrated load. 
     The present invention has been made based on the above findings. The object of the present invention is to provide a roll press machine capable of preventing generation of a concentrated load at a work by finely controlling a gap between a lower roll and an upper roll for consolidating with high precision. 
     Alternatively, the object of the present invention is to provide a controlling system of a roll press machine, the controlling system being capable of preventing generation of a concentrated load at a work by finely controlling a gap between a lower roll and an upper roll for consolidating with high precision. 
     Alternatively, the object of the present invention is to provide a controlling method of a roll press machine, the controlling method being capable of preventing generation of a concentrated load at a work by finely controlling a gap between a lower roll and an upper roll for consolidating with high precision. 
     Solution to Problem 
     The present invention is a roll press machine comprising: a one side roll and another side roll arranged opposite to each other for consolidating a work; a one side roll supporting part configured to support the one side roll in such a manner that the one side roll is rotatable; another side roll supporting part configured to support the other side roll in such a manner that the other side roll is rotatable; a moving apparatus using an electric motor and configured to move the one side roll supporting part and/or the other side roll supporting part relative to each other to control a gap between the one side roll and the other side roll; a work supplying device configured to supply the work through the gap; a position sensor configured to detect a position of a front edge of the work supplied into the gap by the work supplying device; and a controlling device configured to control the moving apparatus based on detection results by the positon sensor; wherein the controlling device is configured to control the moving apparatus in such a manner that the gap is coincided with a consolidating gap at a timing when the front edge of the work has passed through a narrowest position of the gap by a first predetermined distance and that the gap is maintained larger than the consolidation gap until the front edge of the work has passed through the narrowest position of the gap by the first predetermined distance. 
     According to the present invention, since the moving apparatus using the electric motor is adopted, the gap between the one side roll and the other side roll can be finely controlled with high precision. In addition, by carrying out the control wherein the gap is set to the consolidating gap at a timing when the front edge of the work has passed through the narrowest position of the gap by the first predetermined distance, it is possible to effectively prevent generation of a concentrated load when the work is supplied into the gap. 
     According to the results of the experiments carried out by the present inventors, when a material consisting of a plurality of electrode layers having been baked on a metal foil is used as a work, it is effective that the first predetermined distance is within a range of 0.001 mm to 3.000 mm, preferably within a range of 1 mm to 3 mm. 
     In addition, it is preferable that the position sensor is also configured to detect a position of a rear edge of the work supplied into the gap by the work supplying device, and that the controlling device is configured to control the moving apparatus in such a manner that the gap is maintained to the consolidation gap until the rear edge of the work has arrived at a position of a second predetermined distance toward the narrowest position of the gap and that the gap is set larger than the consolidation gap at a timing when the rear edge of the work has arrived at the position of the second predetermined distance toward the narrowest position of the gap. 
     In this case, by carrying out the control wherein the gap is set larger than the consolidation gap at a timing when the rear edge of the work has arrived at the position of the second predetermined distance toward the narrowest position of the gap, it is possible to effectively prevent generation of a concentrated load when the work is moved out of the gap. 
     According to the results of the experiments carried out by the present inventors, when a material consisting of a plurality of electrode layers having been baked on a metal foil is used as a work, it is effective that the second predetermined distance is within a range of 0.001 mm to 3.000 mm, preferably within a range of 1 mm to 3 mm. 
     In addition, the present invention is a roll press machine comprising: a one side roll and another side roll arranged opposite to each other for consolidating a work; a one side roll supporting part configured to support the one side roll in such a manner that the one side roll is rotatable; another side roll supporting part configured to support the other side roll in such a manner that the other side roll is rotatable; a moving apparatus using an electric motor and configured to move the one side roll supporting part and/or the other side roll supporting part relative to each other to control a gap between the one side roll and the other side roll; a work supplying device configured to supply the work through the gap; a load sensor configured to detect a load of the one side roll and/or the other side roll; and a controlling device configured to control the moving apparatus based on detection results by the load sensor; wherein the controlling device is configured to control the moving apparatus, while the work supplying device is operated, in such a manner that the gap is maintained larger than a consolidation gap until the load sensor has detected a predetermined load increase per unit time and that the gap starts being reduced to the consolidation gap at a timing when the load sensor has detected the predetermined load increase per unit time. 
     According to the present invention as well, since the moving apparatus using the electric motor is adopted, the gap between the one side roll and the other side roll can be finely controlled with high precision. In addition, by carrying out the control wherein the gap starts being reduced to the consolidation gap at a timing when (only after) the load sensor has detected the predetermined load increase per unit time when the work is supplied into the gap, it is possible to cause a so-called biting of the work W to precede the control. Thereby, it is possible to effectively prevent generation of a conventional concentrated load when the work W is supplied into the gap. 
     According to the results of the experiments carried out by the present inventors, when a material consisting of a plurality of electrode layers having been baked on a metal foil is used as a work, it is effective to set the predetermined load increase per unit time to a value within a range of 100 N/msec to 1000 N/msec, preferably within a range of 100 N/msec to 200 N/msec. 
     In addition, it is preferable that the controlling device is configured to control the moving apparatus, while the work supplying device is operated after the gap has finished being reduced to the consolidation gap, in such a manner that the gap is maintained to the consolidation gap until the load sensor has detected a predetermined load decrease per unit time and that the gap starts being returned to an original state thereof larger than the consolidation gap at a timing when the load sensor has detected the predetermined load decrease per unit time. 
     In this case, by carrying out the control wherein the gap starts being returned to the original state larger than the consolidation gap at a timing when the load sensor has detected the predetermined load decrease per unit time when the rear edge of the work approaches the narrowest position of the gap (but has not still passed through the narrowest position), it is possible to cause the control to precede a so-called moving-out of the work W. Thereby, it is possible to effectively prevent generation of a conventional concentrated load when the work W is moved out of the gap. 
     According to the results of the experiments carried out by the present inventors, when a material consisting of a plurality of electrode layers having been baked on a metal foil is used as a work, it is effective to set the predetermined load decrease per unit time to a value within a range of 100 N/msec to 1000 N/msec, preferably within a range of 100 N/msec to 200 N/msec. 
     In the above respective inventions, it is preferable that the consolidation gap is a constant value within a range of 70% to 90% of a thickness of the work before consolidation. 
     According to the results of the experiments carried out by the present inventors, when a material consisting of a plurality of electrode layers having been baked on a metal foil is used as a work, if the above conditions are adopted, it is possible to effectively remove or reduce spaces between the electrode layers as well as spaces in the respective electrode layers, which can enhance performance as a battery. 
     Alternatively, it is preferable that the consolidation gap is a value fluctuated with a frequency of 1 Hz to 10 Hz within a range of 70% to 110% of a thickness of the work before consolidation. 
     According to the results of the experiments carried out by the present inventors, when a material consisting of a plurality of electrode layers having been baked on a metal foil is used as a work, if the above conditions are adopted as well, it is possible to effectively remove or reduce spaces between the electrode layers as well as spaces in the respective electrode layers, which can enhance performance as a battery. 
     Furthermore, in this case, compared with a case wherein the consolidation gap is a constant value, the load of the work is reduced, i.e., the loads of various elements for consolidating the work (the one side roll, the other side roll, the one side roll supporting part, the other side roll supporting part) are reduced. Thus, deflection of the various elements is also reduced, so that the roll press machine can be operated much more stably. 
     In addition, the present invention is a controlling system for controlling a roll press machine, the roll press machine including: a one side roll and another side roll arranged opposite to each other for consolidating a work; a one side roll supporting part configured to support the one side roll in such a manner that the one side roll is rotatable; another side roll supporting part configured to support the other side roll in such a manner that the other side roll is rotatable; a moving apparatus using an electric motor and configured to move the one side roll supporting part and/or the other side roll supporting part relative to each other to control a gap between the one side roll and the other side roll; and a work supplying device configured to supply the work through the gap; the controlling system comprising: a position sensor configured to detect a position of a front edge of the work supplied into the gap by the work supplying device; and a controlling device configured to control the moving apparatus based on detection results by the positon sensor; wherein the controlling device is configured to control the moving apparatus in such a manner that the gap is coincided with a consolidating gap at a timing when the front edge of the work has passed through a narrowest position of the gap by a first predetermined distance and that the gap is maintained larger than the consolidation gap until the front edge of the work has passed through the narrowest position of the gap by the first predetermined distance. 
     According to the controlling system of the present invention, by controlling the moving apparatus using the electric motor, the gap between the one side roll and the other side roll can be finely controlled with high precision. In addition, by carrying out the control wherein the gap is set to the consolidating gap at a timing when the front edge of the work has passed through the narrowest position of the gap by the first predetermined distance, it is possible to effectively prevent generation of a concentrated load when the work is supplied into the gap. 
     In addition, the present invention is a controlling system for controlling a roll press machine, the roll press machine including: a one side roll and another side roll arranged opposite to each other for consolidating a work; a one side roll supporting part configured to support the one side roll in such a manner that the one side roll is rotatable; another side roll supporting part configured to support the other side roll in such a manner that the other side roll is rotatable; a moving apparatus using an electric motor and configured to move the one side roll supporting part and/or the other side roll supporting part relative to each other to control a gap between the one side roll and the other side roll; and a work supplying device configured to supply the work through the gap; the controlling system comprising: a load sensor configured to detect a load of the one side roll and/or the other side roll; and a controlling device configured to control the moving apparatus based on detection results by the load sensor; wherein the controlling device is configured to control the moving apparatus, while the work supplying device is operated, in such a manner that the gap is maintained larger than a consolidation gap until the load sensor has detected a predetermined load increase per unit time and that the gap starts being reduced to the consolidation gap at a timing when the load sensor has detected the predetermined load increase per unit time. 
     According to the controlling system of the present invention, by controlling the moving apparatus using the electric motor, the gap between the one side roll and the other side roll can be finely controlled with high precision. In addition, by carrying out the control wherein the gap starts being reduced to the consolidation gap at a timing when (only after) the load sensor has detected the predetermined load increase per unit time when the work is supplied into the gap, it is possible to cause a so-called biting of the work W to precede the control. Thereby, it is possible to effectively prevent generation of a conventional concentrated load when the work W is supplied into the gap. 
     In addition, the present invention is a controlling method of controlling a roll press machine, the roll press machine including: a one side roll and another side roll arranged opposite to each other for consolidating a work; a one side roll supporting part configured to support the one side roll in such a manner that the one side roll is rotatable; another side roll supporting part configured to support the other side roll in such a manner that the other side roll is rotatable; a moving apparatus using an electric motor and configured to move the one side roll supporting part and/or the other side roll supporting part relative to each other to control a gap between the one side roll and the other side roll; and a work supplying device configured to supply the work through the gap; the controlling method comprising the steps of: detecting a position of a front edge of the work supplied into the gap by the work supplying device; and controlling the moving apparatus based on detection results by the detecting step; wherein in the controlling step, the gap is set to a consolidating gap at a timing when the front edge of the work has passed through a narrowest position of the gap by a first predetermined distance and that the gap is maintained larger than the consolidation gap until the front edge of the work has passed through the narrowest position of the gap by the first predetermined distance. 
     According to the controlling method of the present invention, by controlling the moving apparatus using the electric motor, the gap between the one side roll and the other side roll can be finely controlled with high precision. In addition, since the gap is set to the consolidating gap at a timing when the front edge of the work has passed through the narrowest position of the gap by the first predetermined distance, it is possible to effectively prevent generation of a concentrated load when the work is supplied into the gap. 
     In addition, the present invention is a controlling method of controlling a roll press machine, the roll press machine including: a one side roll and another side roll arranged opposite to each other for consolidating a work; a one side roll supporting part configured to support the one side roll in such a manner that the one side roll is rotatable; another side roll supporting part configured to support the other side roll in such a manner that the other side roll is rotatable; a moving apparatus using an electric motor and configured to move the one side roll supporting part and/or the other side roll supporting part relative to each other to control a gap between the one side roll and the other side roll; and a work supplying device configured to supply the work through the gap; the controlling method comprising the steps of: detecting a load of the one side roll and/or the other side roll while the work supplying device is operated; and controlling the moving apparatus based on detection results by the detecting step; wherein, in the controlling step, while the work supplying device is operated, the gap is maintained larger than a consolidation gap until a predetermined load increase per unit time has been detected and that the gap starts being reduced to the consolidation gap at a timing when the predetermined load increase per unit time has been detected. 
     According to the controlling method of the present invention, by controlling the moving apparatus using the electric motor, the gap between the one side roll and the other side roll can be finely controlled with high precision. In addition, by carrying out the control wherein the gap starts being reduced to the consolidation gap at a timing when (only after) the predetermined load increase per unit time has been detected when the work is supplied into the gap, it is possible to cause a so-called biting of the work W to precede the control. Thereby, it is possible to effectively prevent generation of a conventional concentrated load when the work W is supplied into the gap. 
     Advantageous Effects of Invention 
     According to a roll press machine in accordance with one aspect of the present invention, since the moving apparatus using the electric motor is adopted, the gap between the one side roll and the other side roll can be finely controlled with high precision. In addition, by carrying out the control wherein the gap is set to the consolidating gap at a timing when the front edge of the work has passed through the narrowest position of the gap by the first predetermined distance, it is possible to effectively prevent generation of a concentrated load when the work is supplied into the gap. 
     Alternatively, according to a roll press machine in accordance with another aspect of the present invention, since the moving apparatus using the electric motor is adopted, the gap between the one side roll and the other side roll can be finely controlled with high precision. In addition, by carrying out the control wherein the gap starts being reduced to the consolidation gap at a timing when (only after) the load sensor has detected the predetermined load increase per unit time when the work is supplied into the gap, it is possible to cause a so-called biting of the work W to precede the control. Thereby, it is possible to effectively prevent generation of a conventional concentrated load when the work W is supplied into the gap. 
     In addition, according to a controlling system in accordance with one aspect of the present invention, by controlling the moving apparatus using the electric motor, the gap between the one side roll and the other side roll can be finely controlled with high precision. In addition, by carrying out the control wherein the gap is set to the consolidating gap at a timing when the front edge of the work has passed through the narrowest position of the gap by the first predetermined distance, it is possible to effectively prevent generation of a concentrated load when the work is supplied into the gap. 
     Alternatively, according to a controlling system in accordance with another aspect of the present invention, by controlling the moving apparatus using the electric motor, the gap between the one side roll and the other side roll can be finely controlled with high precision. In addition, by carrying out the control wherein the gap starts being reduced to the consolidation gap at a timing when (only after) the load sensor has detected the predetermined load increase per unit time when the work is supplied into the gap, it is possible to cause a so-called biting of the work W to precede the control. Thereby, it is possible to effectively prevent generation of a conventional concentrated load when the work W is supplied into the gap. 
     In addition, according to a controlling method in accordance with one aspect of the present invention, by controlling the moving apparatus using the electric motor, the gap between the one side roll and the other side roll can be finely controlled with high precision. In addition, since the gap is set to the consolidating gap at a timing when the front edge of the work has passed through the narrowest position of the gap by the first predetermined distance, it is possible to effectively prevent generation of a concentrated load when the work is supplied into the gap. 
     Alternatively, according to a controlling method in accordance with another aspect of the present invention, by controlling the moving apparatus using the electric motor, the gap between the one side roll and the other side roll can be finely controlled with high precision. In addition, by carrying out the control wherein the gap starts being reduced to the consolidation gap at a timing when (only after) the predetermined load increase per unit time has been detected when the work is supplied into the gap, it is possible to cause a so-called biting of the work W to precede the control. Thereby, it is possible to effectively prevent generation of a conventional concentrated load when the work W is supplied into the gap. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is a schematic front view showing a roll press machine according to a first embodiment of the present invention; 
         FIG.  2    is a section view taken along line II-II of the roll press machine shown in  FIG.  1   ; 
         FIG.  3    is a section view taken along line III-III of the roll press machine shown in  FIG.  1   ; 
         FIG.  4    is a section view taken along line IV-IV of the roll press machine shown in  FIG.  1   ; 
         FIG.  5    is a section view showing an example of work; 
         FIG.  6    is an explanatory view of displacement sensors of the roll press machine according to the present embodiment; 
         FIG.  7    is a schematic view showing a roll press machine according to a second embodiment of the present invention; 
         FIG.  8    is a schematic view showing a roll press machine according to a variation of the second embodiment of the present invention; 
         FIG.  9    is a schematic flow diagram showing a control example of a roll press machine based on a change of load values detected by load cells; 
         FIG.  10    is a schematic view showing a roll press machine according to a third embodiment of the present invention; 
         FIG.  11    is a schematic side view showing the roll press machine according to the third embodiment of the present invention; 
         FIG.  12    is a section view taken along line XII-XII of  FIG.  11   ; 
         FIG.  13    is a schematic front view showing a roll press machine including a first variation of the electric lifting apparatus; 
         FIG.  14    is a schematic front view showing a roll press machine including a second variation of the electric lifting apparatus; 
         FIG.  15    is a schematic side view of the roll press machine shown in  FIG.  14   ; 
         FIG.  16    is a section view taken along line XVI-XVI of the roll press machine shown in  FIG.  14   ; 
         FIG.  17    is a schematic side view showing a third variation of the electric lifting apparatus; 
         FIG.  18    is a schematic view showing a conventional forming-roll gap adjusting mechanism (which corresponds to FIG. 1 of Patent Document 1); and 
         FIG.  19    is a schematic view showing a conventional path-line adjusting mechanism (which corresponds to FIG. 3 of Patent Document 2). 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     With reference to the attached drawings, embodiments of the present invention are explained below. 
       FIG.  1    is a schematic front view showing a roll press machine  20  according to a first embodiment of the present invention,  FIG.  2    is a section view taken along line II-II of the roll press machine  20  shown in  FIG.  1   ,  FIG.  3    is a section view taken along line III-III of the roll press machine  20  shown in  FIG.  1   , and  FIG.  4    is a section view taken along line IV-IV of the roll press machine  20  shown in  FIG.  1   . As shown in  FIGS.  1  and  2   , the roll press machine  20  of the present embodiment has a pair of electric lifting apparatuses  10 . At first, with reference to  FIG.  1   , the electric lifting apparatus  10  is explained. 
     [Structure of Electric Lifting Apparatus] 
     The electric lifting apparatus  10  of the present embodiment includes a ball screw  11 . The ball screw  11  has: a threaded shaft  11   a  having an axis x; a pair of bearings  11   b ,  11   c  provided at both end parts of the threaded shaft  11   a  and configured to support the threaded shaft  11   a  in such a manner that the threaded shaft  11   a  is rotatable around the axis x; and a nut  11   d  threadedly engaged with the threaded shaft  11   a  via a plurality of rolling elements (not shown) in such a manner that the nut  11   d  moves linearly in a direction of the axis x when the threaded shaft  11   a  rotates. 
     The axis x of the threaded shaft  11   a  is parallel to an axis of a lower roll  23  (one side roll) and an axis of an upper roll  24  (the other side roll), which are described below. The bearing  11   b  on the roll side (on the inner side) is buried in (supported by) an inside frame wall  12   b . The bearing  11   c  on the opposite side (on the outer side) is buried in (supported by) a central frame wall  12   c . The inside frame wall  12   b  and the central frame wall  12   c  are erected on an upper surface of a plate-like frame bottom plate  12   a . An outside frame wall  12   d  is provided to face the inside frame wall  12   b . The outside frame wall  12   d  is also erected on the upper surface of the frame bottom plate  12   a . A frame ceiling plate  12   g  provided with an opening  12   h , through which a load cell extends, is laid on across the inside frame wall  12   b  and outside frame wall  12   d.    
     A substantially central part of a lower surface of the frame bottom plate  12   a  is supported by a lower part  26   a  of a roll frame  26  (see  FIG.  2   ), which is described below. An outside part of the lower surface of the frame bottom plate  12   a  is fixed to a quadrangular prism  12   e , which is erected on a base  40 . Thus, the frame bottom plate  12   a  is fixed to the base  40 . In addition, an electric motor mounting plate  12   f , which has a L-shaped section, is fixed to a part of the lower surface of the frame bottom plate  12   a  directly below the inside frame wall  12   b.    
     A frame  12  is formed by the frame bottom plate  12   a , the inside frame wall  12   b , the central frame wall  12   c , the outside frame wall  12   d , the quadrangular prism  12   e , the electric motor mounting plate  12   f  and the frame ceiling plate  12   g . These components of the frame  12  may be integrally formed, or may be separately formed and subsequently fixed to each other. 
     As an example, when a lifting force (pressing force) of the electric lifting apparatus  10  is 300 kN as a nominal value (600 kN for a pair of right and left ones) and a diameter of each roll is 450 mm, a size of each of the frame bottom plate  12   a  and the frame ceiling plate  12   g  is 50 cm (length seen in  FIG.  1   )×40 cm (length seen in  FIG.  2   ) in a plan view, and a thickness thereof is about 6 cm. A size of the quadrangular prism  12   e  is 10 cm×40 cm in a plan view, and a height thereof is the same as that of the lower part  26   a  of the frame  26 . A wall thickness of each of the inside frame wall  12   b  and the outside frame wall  12   d  is about 6 cm, and a height thereof is about 30 cm. A wall thickness of the central frame wall  12   c  is about 5 cm, and a height thereof is about 15 cm. 
     As shown in  FIG.  1   , an electric motor  13  having an output shaft  13   s  being rotatable (preferably a servomotor) is fixed to the electric motor mounting plate  12   f . The output shaft  13   s  of the electric motor  13  is parallel with the axis x of the threaded shaft  11   a  of the ball screw  11 , and they are overlapped with each other in a plan view. Thereby, the electric lifting apparatus  10  is made compact significantly. 
     At the time of filing the present application, the present invention is not limited to a manner in which the output shaft  13   s  of the electric motor  13  and the axis x of the threaded shaft  11   a  of the ball screw  11  are completely overlapped with each other in a plan view, but includes a manner in which the output shaft  13   s  of the electric motor  13  and the axis x of the threaded shaft  11   a  of the ball screw  11  are only partially overlapped with each other in a plan view. The degree of the compactness depends on the degree of the overlapping. 
     Referring back to  FIG.  1   , the output shaft  13   s  of the electric motor  13  extends through a suspended part of the electric motor mounting plate  12   f , and is protruded inside the frame  12  and fixed to a motor side pulley  13   p . On the other hand, the threaded shaft  11   a  of the ball screw  11  has a protruded part, which extends outward through the bearing  11   b  on the roll side (on the inner side) and is fixed to a threaded-shaft side pulley  11   p . A belt  14  is laid on around the motor side pulley  13   p  and the threaded-shaft side pulley  11   p.    
     As an example, the motor side pulley  13   p  and the threaded-shaft side pulley  11   p  have a diameter of about 8 cm to 12 cm in common. In addition, the motor side pulley  13   p  and the threaded-shaft side pulley  11   p  have a width (thickness) of about 4 cm in common. A width of the belt  14  is slightly narrower than this width and is about 3.5 cm for example. A length of the belt  14  depends on a distance between the axis x of the threaded shaft  11   a  and the output shaft  13   s  of the electric motor  13  and is about 70 to 80 cm for example. In some cases, a reduction gear may be formed by increasing the number of teeth of the threaded-shaft side pulley  11   p  with respect to the number of teeth of the motor side pulley  13   p.    
     The motor side pulley  13   p , the threaded-shaft side pulley  11   p  and the belt  14  are configured to function as a rotational force transferring mechanism which transfers a rotational force of the output shaft  13   s  to a rotational force of the threaded shaft  11   a . Specifically, such a rotational force transferring mechanism may consist of: toothed pulleys and a toothed belt, timing pulleys and a timing belt, or any other combination. As clearly seen from  FIG.  1   , the belt  14  is configured to circulate on a circulating track which extends in a plane perpendicular to the output shaft  13   s  and the axis x of the threaded shaft  11   a.    
     A first moving body  15  is fixed to the nut  11   d  of the ball screw  11  and is movable integrally with the nut  11   d . The first moving body  15  has a first sliding surface  15   t  inclined at a predetermined angle with respect to a plane including the direction of the axis x of the threaded shaft  11   a.    
     In the present embodiment, as shown in  FIG.  2   , two first sliding surfaces  15   t  are provided, and the two first sliding surfaces  15   t  are arranged on both sides with respect to the threaded shaft  11   a  and at predetermined distances from the threaded shaft  11   a  in a horizontal direction perpendicular to both the direction of the axis x and a vertical direction. Each of the two first sliding surfaces  15   t  is parallel with the direction of the axis x of the threaded shaft  11   a  in a plan view. 
     In addition, in the present embodiment, as clearly seen from  FIG.  1   , the threaded shaft  11   a  extends through the first moving body  15  in the direction of the axis x. The pair of bearings  11   b ,  11   c  is arranged on both sides of the first moving body  15 . 
     A first sliding guide  16 , which extends in parallel with the direction of the axis x, is provided on the upper surface of the frame bottom plate  12   a . The first moving body  15  is provided with a first sliding part  15   s  which is slidably movable relative to the first sliding guide  16 . 
     In the present embodiment, as shown in  FIGS.  2  and  4   , two pairs of the first sliding guide  16  and the first sliding part  15   s  are provided, and the two pairs of the first sliding guide  16  and the first sliding part  15   s  are arranged on both sides with respect to the threaded shaft  11   a  and at predetermined distances from the threaded shaft  11   a  in the horizontal direction perpendicular to both the direction of the axis x and the vertical direction. The sliding surfaces of the first sliding guide  16  and the first sliding part  15   s  extend in parallel with the direction of the axis x of the threaded shaft  11   a  in a plan view. 
     In addition, the electric lifting apparatus  10  according to the present embodiment has a second moving body  18  arranged to be movable linearly in a direction perpendicular to the direction of the axis x with respect to the frame  12 . The second moving body  18  has two second sliding surfaces  18   t , which are slidably movable relative to the two first sliding surfaces  15   t , respectively. Thereby, the second moving body  18  is caused to move linearly in the above perpendicular direction by a sliding movement between the two first sliding surfaces  15   t  and the two second sliding surfaces  18   t  when the nut  11   d  and the first moving body  15  moves linearly in the direction of the axis x. Herein, in the present embodiment, as shown in  FIG.  2   , it can be said that there are two pairs of the first sliding surface  15   t  and the second sliding surface  18   t , and that the two pairs are arranged on both sides with respect to the threaded shaft  11   a  and at predetermined distances from the threaded shaft  11   a  in the horizontal direction perpendicular to both the direction of the axis x and the vertical direction. 
     It is preferable that the pairs of the first sliding surface  15   t  and the second sliding surface  18   t  are arranged symmetrically with respect to the threaded shaft  11   a . In this case, a linear movement (horizontal movement) of the first moving body  15  can be converted to a linear movement (up and down movement) of the second moving body  18  in a well-balanced manner. A load (reaction force) received by the second moving body  18  can be also supported by the base  40  via the first moving body  15   t  and so on in a well-balanced manner. 
     As a specific structural example, each pair of the first sliding surface  15   t  and the second sliding surface  18   t  may be provided by a general linear guide. That is to say, with reference to  FIG.  2   , the first sliding surface  15   t  may be provided as a concave surface, whose section has a concave shape, of a member which is called “block” of the linear guide, and the second sliding surface  18   t  may be provided as a lower surface, whose section has a rectangular shape, of a member which is called “rail” of the linear guide. For example, commercially available two linear guides may be disassembled, and subsequently two “blocks” thereof may be fixed to an upper surface of a main body of the first moving body  15  and two “rails” thereof may be fixed to a lower surface of a main body of the second moving body  18 , which may result in that the two pairs are arranged. 
     A second sliding guide  19  extending in the above perpendicular direction (the direction perpendicular to the direction of the axis x) is provided on an inside surface of the outside frame wall  12   d . The second moving body  18  is provided with a second sliding part  18   s  which is slidably movable relative to the second sliding guide  19 . 
     In the present embodiment, as shown in  FIGS.  3  and  4   , two pairs of the second sliding guide  19  and the second sliding part  18   s  are provided, and the two pairs of the second sliding guide  19  and the second sliding part  18   s  are arranged on both sides with respect to the threaded shaft  11   a  and at predetermined distances from the threaded shaft  11   a  in the horizontal direction perpendicular to both the direction of the axis x and the vertical direction. 
     In addition, in the present embodiment, a load cell  21  is provided on an upper surface of the second moving body  18 . The load cell  21  is configured to be movable up and down through the opening  12   h  of the frame ceiling plate  12   g.    
     Coil springs  28 , each of which has been always compressed (correspondingly to a load of about 10 kN), are inserted between the upper surface of the second moving body  18  and a lower surface of the frame ceiling plate  12   g  at inside and outside positions adjacent to the load cell  21 . 
     Herein, the predetermined angle may be selected within a range of 5.7 degrees to 11.3 degrees. The “5.7 degrees” is the solution of tan θ=1/10. The “11.3 degrees” is the solution of tan θ=1/5. Thus, a leverage ratio (lever mechanism ratio) of 5 to 10 times can be achieved. 
     Through the practical verification experiments carried out by the present inventors, it has been confirmed that the electric lifting apparatus  10  of the present embodiment is effectively operable within the above angle range. 
     A moving stroke of the second moving body  18  may be 1 mm, which is enough for an application as described below (an application in which a material in which a plurality of electrode layers having been baked on a metal foil is used as a work W). 
     A moving speed of the second moving body  18  may be 10 mm/sec, for example, which corresponds to a moving speed of the first moving body  15  (i.e., the nut  11   d ) of 50 mm/sec when the leverage ratio is 5 times, or a moving speed of the first moving body  15  (i.e., the nut  11   d ) of 100 mm/sec when the leverage ratio is 10 times. Such a moving speed of the nut  11   d  can be achieved by a commercially available general electric motor  13  and a commercially available general ball screw  11 . In particular, when the electric motor  13  is a servomotor, a control with higher precision and higher responsivity can be achieved. 
     [Operation of Electric Lifting Apparatus  10 ] 
     Next, an operation of the electric lifting apparatus  10  of the present embodiment is explained. 
     When the electric motor  13  is driven in a desired manner (for example, the electric motor  13  may be controlled by a controlling device  35  as described below), the output shaft  13   s  of the electric motor  13  rotates. Subsequently, the motor side pulley  13   p , the threaded-shaft side pulley  11   p  and the belt  14  function as a rotational force transferring mechanism, so that a rotational force of the output shaft  13   s  is transferred to a rotational force of the threaded shaft  11   a . Subsequently, a rotation of the threaded shaft  11   a  is converted to a linear movement of the nut  11   d  in the direction of the axis x by a converting function of the ball screw  11  between the rotational movement and the linear movement. 
     Thereby, the first moving body  15  fixed to the nut  11   d  moves linearly in the direction of the axis x. Herein, the linear movement of the first moving body  15  in the direction of the axis x is smoothly achieved because of an interaction between the first sliding guide  16  and the first sliding part  15   s  (a facilitating action of a smooth sliding movement). 
     Subsequently, when the nut  11   d  and the first moving body  15  move linearly in the direction of the axis x, the second moving body  18  moves linearly in the direction perpendicular to the direction of the axis x, by a sliding movement between the first sliding surface  15   t  and the second sliding surface  18   t . Herein, the linear movement of the second moving body  18  is smoothly achieved because of an interaction between the second sliding guide  19  and the second sliding part  18   s  (a facilitating action of a smooth sliding movement). 
     If the pairs of the first sliding surface  15   t  and the second sliding surface  18   t  are arranged symmetrically with respect to the threaded shaft  11   a , the linear movement (horizontal movement) of the first moving body  15  can be converted to the linear movement (up and down movement) of the second moving body  18  in a well-balanced manner, and a load (reaction force) received by the second moving body  18  can be also supported by the base  40  via the first moving body  15   t  and so on in a well-balanced manner. 
     In short, when the electric motor  13  is driven in a desired manner, the movement of the second moving body  18  can be controlled in a desired manner with high precision. In particular, when the electric motor  13  is a servomotor, a control with higher precision and higher responsivity can be achieved. 
     In particular, since the compressed coil springs  28  always press the ball screw  11  toward the side of the bearings  11   b ,  11   c , it is possible to remove the effects by backlash which might be caused in the ball screw  11 , so that a lifting control with higher precision can be achieved. 
     In addition, because of a cushion action of the belt  14 , it is possible to mitigate a shock which might be transferred to the electric motor  13  via the threaded shaft  11   a.    
     [Effects of Electric Lifting Apparatus  10 ] 
     As described above, according to the electric lifting apparatus  10  of the present embodiment, the rotational force of the output shaft  13   s  of the electric motor  13  is used as the rotational force of the threaded shaft  11   a  of the ball screw  11 , and the second moving body  18  moves linearly in the direction perpendicular to the direction of the axis x when the first moving body  15  fixed to the nut  11   d  of the ball screw  11  moves linearly in the direction of the axis x. Thereby, the movement of the second moving body  18  can be controlled with high precision by the electric motor  13 . 
     In addition, according to the electric lifting apparatus  10  of the present embodiment, since the threaded shaft  11   a  extends through the first moving body  15  in the direction of the axis x and the pair of bearings  11   b ,  11   c  is arranged on the both sides of the first moving body  15 , the whole electric lifting apparatus  10  is compact. In addition, according to the electric lifting apparatus  10  of the present embodiment, as seen in the direction in which the second moving body  18  is linearly movable, the electric motor  13  and the threaded shaft  11   a  are completely overlapped with each other along the direction of the axis x. This also contributes to making the whole electric lifting apparatus  10  compact. Furthermore, since a hydraulic system is not adopted, i.e., since there is no concern about pollution of the surrounding by oil, the electric lifting apparatus  10  of the present embodiment is suitable to be displaced in a glove box. 
     In addition, according to the electric lifting apparatus  10  of the present embodiment, the rotational force transferring mechanism, which transfers the rotational force of the output shaft  13   s  as the rotational force of the threaded shaft  11   a , has the belt  14  laid on around the motor side pulley  13   p  of the output shaft  13   s  and the threaded-shaft side pulley  11   p  of the threaded shaft  11   a  in such a manner that the belt  14  circulates on the circulating track which extends in the plane perpendicular to the output shaft  13   s  and the axis x of the threaded shaft  11   a . According to this arrangement, the rotational force transferring mechanism is compact, and thus the whole electric lifting apparatus  10  is more compact. Thus, the electric lifting apparatus  10  according the present embodiment is more suitable to be displaced in a glove box. 
     In addition, according to the electric lifting apparatus  10  of the present embodiment, the pair of bearings  11   b ,  11   c  for the threaded shaft  11   a  is arranged at the both end parts of the threaded shaft  11   a , and the belt  14  is laid over the protruded part of the threaded shaft  11   a  which extends outward through the one bearing  11   b . According to this arrangement, the whole electric lifting apparatus  10  is more compact, and thus the electric lifting apparatus  10  according the present embodiment is much more suitable to be displaced in a glove box. 
     In addition, according to the electric lifting apparatus  10  of the present embodiment, the frame  12  is provided with the first sliding guide(s)  16  which extends in parallel with the direction of the axis x, and the first moving body  15  is provided with the first sliding part(s)  15   s  which is slidably movable relative to the first sliding guide(s)  16 . Thereby, because of the interaction therebetween (the facilitating action of the smooth sliding movement), the movement of the first moving body  15  in the direction of the axis x is more smoothly achieved. 
     In addition, according to the electric lifting apparatus  10  of the present embodiment, the two pairs of the first sliding surface  15   t  and the second sliding surface  18   t  are provided on the both sides with respect to the threaded shaft  11   a  and at the predetermined distances from the threaded shaft  11   a  in the horizontal direction perpendicular to both the direction of the axis x and the vertical direction. According to this feature, during a roll press operation, when a reaction force or the like exerted on the second moving body  18  is transferred to the first moving body  15  via the pairs of the first sliding surface  15   t  and the second sliding surface  18   t , a load which the ball screw  11  directly receives can be reduced. Thereby, it is possible to remarkably reduce a possibility that malfunction will occur in the ball screw  11 . 
     Furthermore, according to the electric lifting apparatus  10  of the present embodiment, the two pairs of the first sliding guide  16  and the first sliding part  15   s  are also provided on the both sides with respect to the threaded shaft  11   a  and at the predetermined distances from the threaded shaft  11   a  in the horizontal direction perpendicular to both the direction of the axis x and the vertical direction. According to this feature as well, during a roll press operation, when a reaction force or the like exerted on the second moving body  18  is transferred to the first moving body  15  via the pairs of the first sliding surface  15   t  and the second sliding surface  18   t , a load which the ball screw  11  directly receives can be reduced. Thereby, it is possible to remarkably reduce a possibility that malfunction will occur in the ball screw  11 . 
     In addition, according to the electric lifting apparatus  10  of the present embodiment, the frame  12  is provided with the second sliding guide(s)  19  which extends perpendicularly to the direction of the axis x, and the second moving body  18  is provided with the second sliding part(s)  18   s  which is slidably movable relative to the second sliding guide(s)  19 . Thereby, because of the interaction therebetween (the facilitating action of the smooth sliding movement), the movement of the second moving body  18  in the direction perpendicular to the direction of the axis x is more smoothly achieved. 
     [Structure of Roll Press Machine  20 ] 
     With reference to  FIGS.  1  and  2   , a structure of a roll press machine  20  according to an embodiment is explained. 
     The roll press machine  20  according to the present embodiment includes a pair of the above described electric lifting apparatuses  10 . A pair of lower roll supporting bodies  22  (one side roll supporting parts) are respectively supported by the pair of second moving bodies  18  of the pair of electric lifting apparatuses  10 . Each of the pair of lower roll supporting bodies  22  is placed on the corresponding second moving body  18  via the load cell  21 . The pair of lower roll supporting bodies  22  has bearings configured to support a lower roll  23  in such a manner that the lower roll  23  is rotatable. 
     An upper roll  24  is arranged opposite to the lower roll  23 . A press forming (consolidating) of a work W is carried out by using a gap formed between the lower roll  23  and the upper roll  24 . 
     The upper roll  24  is supported by a pair of upper roll supporting bodies  25  (the other side roll supporting parts) in such a manner that the upper roll  24  is rotatable. Each of the pair of upper roll supporting bodies  25  is fixed to each of a pair of roll frames  26  provided on the base  40 , for example via bolt screws or the like not shown from outside. 
     In addition, as shown in  FIG.  2   , a pair of opposite third sliding guides  27 , each of which extends perpendicularly to the direction of the axis x, are provided on opposite inside surfaces of each roll frame  26 , and each of the pair of lower roll supporting bodies  22  is provided with pairs of opposite third sliding parts  22   s  which are slidably movable relative to the opposite third sliding guides  27 . In addition, the lower part  26   a  of the roll frame  26  fixes the frame bottom plate  12   a  of the electric lifting apparatus  10  to the base  40 . Thereby, a part of the electric lifting apparatus  10  is inserted in an opening of the roll frame  26 , so that the whole apparatus layout is made compact. 
     According to the above structure, the pair of electric lifting apparatuses  10  is configured to function as a moving apparatus for causing the lower roll supporting bodies  22  and the upper roll supporting bodies  25  to move relative to each other by using the electric motors  13 , to control the gap between the lower roll  23  and the upper roll  24 . 
     Referring back to  FIG.  1   , four displacement sensors  30  are provided for measuring local displacements at predetermined positions of the lower roll  23  and the upper roll  24 , for example at positions 30 mm away from their left and right ends (only three of them are shown in  FIG.  1   ). The displacement sensors  30  are fixed to the base  40  via a displacement sensor frame  31 , which is different from the roll frame  26 . The displacement sensors  30  are connected to the controlling device  35  for controlling the electric motors  13 . The displacement sensors  30  of the present embodiment are specifically non-contact type displacement gauges. 
     As an example, the lower roll  23  and the upper roll  24  have a diameter of about 30 to 50 cm in common, and a length (width) of about 15 to 50 cm in common in the direction of the axis x. The whole size of the roll press machine  20  is within 180 cm in height×150 cm in width (×90 cm in depth). 
     [Basic Operation of Roll Press Machine  20 ] 
     A basic operation of the roll press machine  20  of the present embodiment is explained. 
     As a basic operation, the respective electric motors  13  of the pair of electric lifting apparatuses  10  are driven in a desired matter, so that the positions of the second moving bodies  18  are controlled in a desired manner with high precision, and thus the respective positions of the pair of lower roll supporting bodies  22  are controlled in a desired manner with high precision. 
     Thereby, the dimension of the gap formed between the lower roll  23  and the upper roll  24  can be controlled in a desired manner with high precision. Therefore, thickness precision of a press-formed work W can be maintained constant with high precision. 
     [Specific Example of Work W] 
     Herein, a material in which a plurality of electrode layers (broad concept including solid electrolyte layers) having been baked on a metal foil is assumed as a work W. Specifically, as shown in  FIG.  5    for example, a copper foil  81  intended to function as a cathode is used as a base material, and a cathode layer  82 , a solid electrolyte layer  83  and an anode layer  84  are formed thereon in this order from the bottom. Alternatively, an aluminum foil intended to function as an anode may be used as a base material, and an anode layer, a solid electrolyte layer and a cathode layer may be formed thereon in this order from the bottom. The plurality of electrode layers are applied and/or baked intermittently on a continuous metal foil, so that discrete works W are formed (see  FIGS.  5  and  7   ). 
     A thickness of the material is 0.38 mm, for example, before a press-forming (consolidating). It is intended to reduce the thickness to 0.34 mm by a press-forming (consolidating) to remove or reduce spaces between the electrode layers as well as spaces in the respective electrode layers. In this case, taking into consideration a spring back of the material, it is preferable that the size of the gap formed between the lower roll  23  and the upper roll  24  at a press-forming (consolidating) is set to 0.25 to 0.3 mm. 
     According to verification results by the present inventors, when the purpose is to remove or reduce the spaces between the electrode layers and the spaces in the respective electrode layers by press-forming the material in which the plurality of electrode layers having been baked on the metal foil, it is effective to set the gap (which is also called “consolidation gap” in the specification) formed between the lower roll  23  and the upper roll  24  at a press-forming (consolidating) to a constant value within a range of 70% to 90% of the thickness of the work W before the consolidation. 
     In addition, according to further verification results by the present inventors, when the purpose is to remove or reduce the spaces between the electrode layers and the spaces in the respective electrode layers by press-forming the material in which the plurality of electrode layers having been baked on the metal foil, it is also effective to set a feed speed of the work W to a value within a range of 1 mm/sec to 100 mm/sec and to carry out an intermittent roll press operation by fluctuating the consolidation gap within a range of 70% to 110% of the thickness of the work W before the consolidation with a frequency of 1 Hz to 10 Hz (1 to 10 times a second) in order to generate impact loads. In this case, it is possible to reduce power consumption with respect to a compression rate. That is to say, it is possible to obtain energy saving effects. 
     As a specific example, when the thickness of the material is 0.38 mm before a press-forming (consolidating) and it is intended to reduce the thickness to 0.34 mm by a press-forming (consolidating) to remove or reduce the spaces between the electrode layers and the spaces in the respective electrode layers, 
     it is effective to fluctuate the size of the gap formed between the lower roll  23  and the upper roll  24  at a press-forming (consolidating) within a range of 0.27 mm to 0.42 mm with a frequency of 1 Hz to 10 Hz (1 to 10 times a second) (in a case wherein the feed speed of the work W is within a range of 1 mm/sec to 100 mm/sec). 
     In detail, the fluctuation of the size of the gap with respect to time may be like a rectangular pulse, like a sawtooth wave, or like a sinusoidal wave. 
     According to verification results by the present inventors, when the fluctuated value as described above is adopted as the consolidation gap (when an intermittent roll press operation is carried out), it has been confirmed that power consumption with respect to a compression rate, at which the material is compressed by the press-forming (consolidating), can be reduced by about 10%, compared with a case wherein a constant value is adopted as the consolidation gap. 
     [Displacement Compensation of Roll Press Machine  20 ] 
     At a press forming (consolidating), because of a reaction from the work W, the upper roll  24  (together with the upper roll supporting body  25  supporting the upper roll  24 ) is going to deflect upward, and the lower roll  23  (together with the lower roll supporting body  22  supporting the lower roll  23 ) is going to deflect downward. This situation is shown in  FIG.  6    by a one-dot chain line. 
     In the roll press machine  20  of the present embodiment, as shown in  FIGS.  1  and  6   , four displacement sensors  30  are provided to enable to take measures against (compensate for) generation of the deflection (displacement). That is to say, the controlling device  35  carries out a control taking into consideration the displacements of the upper roll  24  and the lower roll  23 , based on respective measurement results of the four displacement sensors  30 . In detail, for example, a further “push control” may be carried out depending on the displacements of the upper roll  24  and the lower roll  23 . 
     In the roll press machine  20  of the present embodiment, since the displacement sensor frame  31  supporting the displacement sensors  30  is different from the roll frame  26 , the mounted positions of the displacement sensors  30  are not affected by deflection of the various elements (the lower roll  23 , the upper roll  24 , the lower roll supporting body  22 , the upper roll supporting body  25 ) at a press-forming (consolidating). Thereby, measurements by the displacement sensors  30  and thus a feedback control based on the measurement results can be carried out with high precision. 
     [Load Monitoring/Load Control of Roll Press Machine  20 ] 
     In the roll press machine  20  of the present embodiment, the lower roll supporting bodies  22  are placed on the second moving bodies  18  of the electric lifting apparatuses  10  via the load cells  21 . By monitoring values of the load cells  21 , it is possible to monitor occurrence of an abnormal load at the lower roll  23  and/or the upper roll  24 , for example. 
     Furthermore, by connecting the load cells  21  to the controlling device  35 , it is also possible to carry out a load control using measurement results of the load cells  21 . For example, by setting a target load value or a target load range in advance, it is possible to carry out a feedback control based on the target load value or the target load range. 
     [Structure of Roll Press Machine  50 ] 
     Next,  FIG.  7    is a schematic view of a roll press machine  50  according to a second embodiment of the present invention. In the roll press machine  50  of the present embodiment, components described below are added to the roll press machine  20  of the first embodiment. In  FIG.  7   , except for the lower roll  23  and the upper roll  24 , the components of the roll press machine  20  of the first embodiment are not shown. In addition, in the present embodiment, each of the lower roll  23  and the upper roll  24  is configured to be driven by a servomotor. 
     As shown in  FIG.  7   , the added components in the present embodiment are: feed rolls  51  as a work supplying device that supplies a work W through the gap between the lower roll  23  and the upper roll  24 ; and a position sensor  52  configured to detect a position of a front edge of the work W supplied into the gap by the feed rolls  51 . The position sensor  52  is connected to the controlling device  35 . The feed rolls  51  are also configured to be driven by servomotors. 
     Specifically, the position sensor  52  of the present embodiment is a non-contact type displacement gauge disposed at a position of a predetermined basic distance C away from the narrowest position of the gap (corresponding to axes of the lower roll  23  and the upper roll  24 ). For example, the position sensor  52  is a laser type position sensor. When the front edge F of the work W (see  FIG.  7   ) passes through a detection positon of the position sensor  52 , an output of the position sensor  52  is changed depending on a change of the thickness of the work W. Through the detection of the change, it is possible to detect when the front edge F of the work W arrives at the detection position of the position sensor  52 . That is to say, it is possible to detect a position of the front edge F of the work W. Alternatively, the position sensor  52  may be a sensor for judging a color of the work W. Through the judgment of the color of the uppermost electrode or the like of the work W as well, it is possible to detect when the front edge F of the work W arrives at the detection position of the position sensor  52 . That is to say, it is possible to detect a position of the front edge F of the work W. 
     On the other hand, if the feed speed of the work W by the feed rolls  51  is obtained, the front edge F of the work W arrives at the narrowest position of the gap at a timing when a time period obtained by dividing the predetermined basic distance C by the feed speed has passed after the front edge F of the work W arrived at the detection position of the position sensor  52 . The feed speed of the work W may be obtained from information about a driving system for the feed rolls  51 , or may be measured by an encoder  53  provided on the feed rollers  51 . 
     The present inventors have found that, at a press-forming for the material in which the plurality of electrode layers having been baked on the metal foil, when the material is supplied as a work W into the gap between the lower roll and the upper roll for consolidating, a concentrated load may be generated at a front edge of the work W. In that case, chipping or crackling may be caused at the material (at the front edge of the material). 
     Furthermore, the present inventors have found that, it is remarkably effective to set the gap to the consolidation gap only after the front edge F of the work W has passed through the narrowest position of the gap by a first predetermined distance, i.e., to maintain the gap larger than the consolidation gap (and larger than the thickness of the work W) until the front edge F of the work W has passed through the narrowest position of the gap by the first predetermined distance, in order to prevent the chipping or crackling at the material (at the front edge of the material). Preferably, the first predetermined distance is selected within a range of 0.001 mm to 3.000 mm, more preferably within a range of 1 mm to 3 mm, although it may depend on the type and/or the thickness of the material. 
     Based on these findings, the controlling device  35  of the present embodiment controls the electric motors  13  of the electric lifting apparatuses  10  based on the detection results by the position sensor  52  and the feed speed of the work W by the feed rolls  51  obtained in advance in such a manner that the gap is set to the consolidation gap at a timing when the front edge F of the work W has passed through the narrowest position of the gap by the first predetermined distance, i.e., the gap is maintained larger than the consolidation gap (and larger than the thickness of the work W) until the front edge F of the work W has passed through the narrowest position of the gap by the first predetermined distance. 
     In addition, the present inventors have also found that, at a press-forming for the material in which the plurality of electrode layers having been baked on the metal foil, when the material is moved out of the gap between the lower roll and the upper roll for consolidating, a concentrated load may be generated at the work W. In that case, chipping or crackling may be caused at the material. 
     Furthermore, the present inventors have found that, it is remarkably effective to maintain the gap to the consolidation gap until the rear edge R of the work W has arrived at a position of a second predetermined distance toward the narrowest position of the gap, and to set the gap larger than the consolidation gap (and larger than the thickness of the work W) at a timing when the rear edge R of the work W has arrived at the position of the second predetermined distance toward the narrowest position of the gap, in order to prevent the chipping or crackling at the material (at the edge of the material). Preferably, the second predetermined distance is also selected within a range of 0.001 mm to 3.000 mm, more preferably within a range of 1 mm to 3 mm, although it may depend on the type and/or the thickness of the material. 
     In the present embodiment, when the rear edge R of the work W (see  FIG.  7   ) passes through the detection positon of the position sensor  52  as well, the output of the position sensor  52  is changed depending on a change of the thickness of the work W. Through the detection of the change, it is possible to detect when the rear edge R of the work W arrives at the detection position of the position sensor  52 . 
     Based on these findings, the controlling device  35  of the present embodiment controls the electric motors  13  of the electric lifting apparatuses  10  based on the detection results by the position sensor  52  and the feed speed of the work W by the feed rolls  51  obtained in advance in such a manner that the gap is maintained to the consolidation gap until the rear edge R of the work W has arrived at the position of the second predetermined distance toward the narrowest position of the gap, and that the gap is set larger than the consolidation gap at a timing when the rear edge R of the work W has arrived at the position of the second predetermined distance toward the narrowest position of the gap. 
     In addition, in the present embodiment, since the lower roll  23  and the upper roll  24  are driven by servomotors, it is possible to synchronize them to the feed roils  51  with high precision. Thereby, it is possible to achieve a feed control of the work W with high precision. Furthermore, when a thermal process is added to the lower roll  23  and the upper roll  24 , the lower roll  23  and the upper roll  24  may be thermally deformed (in particular, diameters thereof may be changed). However, for example by using a temperature detection by a temperature sensor, an appropriate compensation control can be carried out. 
     [Operation of Roll Press Machine  50 ] 
     According to the roll press machine  50  of the present embodiment, it is detected by the position sensor  52  that the front edge F of the work W has arrived at the detection position of the position sensor  52 . Then, based on the predetermined basic distance C, the first predetermined distance and the feed speed of the work W, the controlling device  35  controls the electric motors  13  of the electric lifting apparatuses  10  in such a manner that the gap is adjusted to the consolidation gap with high precision at a timing when the front edge F of the work W has passed through the narrowest position of the gap by the first predetermined distance. In other words, until the front edge F of the work W has passed through the narrowest position of the gap by the first predetermined distance, the gap is maintained larger than the consolidation gap (and larger than the thickness of the work W). 
     Thus, it is possible to effectively prevent generation of the concentrated load when the work W is supplied into the gap, and thus it is possible to effectively prevent generation of the chipping or crackling at the front edge portion of the work W. 
     In addition, according to the roll press machine  50  of the present embodiment, it is detected by the position sensor  52  that the rear edge R of the work W has arrived at the detection position of the position sensor  52 . Then, based on the predetermined basic distance C, the second predetermined distance and the feed speed of the work W, the controlling device  35  controls the electric motors  13  of the electric lifting apparatuses  10  in such a manner the gap is maintained to the consolidation gap until the rear edge R of the work W has arrived at the position of the second predetermined distance toward the narrowest position of the gap, and that the gap is set larger than the consolidation gap at a timing when the rear edge R of the work W has arrived at the position of the second predetermined distance toward the narrowest position of the gap. 
     Thus, it is possible to effectively prevent generation of the concentrated load when the work W is moved out of the gap, and thus it is possible to effectively prevent generation of the chipping or crackling at the rear edge portion of the work W. 
     In the roll press machine  50  of the present embodiment as well, it is effective to set the consolidation gap to a constant value within a range of 70% to 90% of the thickness of the work W before the consolidation. Alternatively, it is also effective to set the feed speed of the work W to a value within a range of 1 mm/sec to 100 mm/sec and to carry out a cycling operation by fluctuating the consolidation gap within a range of 70% to 110% of the thickness of the work W before the consolidation with a frequency of 1 Hz to 10 Hz (1 to 10 times a second). In the latter case, it is possible to reduce power consumption with respect to a compression rate, at which the material is compressed by the press-forming (consolidating), by about 10%, as described above. 
     [Structure of Roll Press Machine  150 ] 
     Next,  FIG.  8    is a schematic view of a roll press machine  150 , which is a variation of the roll press machine  50  according to the second embodiment of the present invention. In the roll press machine  150 , components described below are added to the roll press machine  20  of the first embodiment. In  FIG.  8    as well, except for the lower roll  23  and the upper roll  24 , the components of the roll press machine  20  of the first embodiment are not shown. In addition, in the present variation as well, each of the lower roll  23  and the upper roll  24  is configured to be driven by a servomotor. 
     As shown in  FIG.  8   , the added components in the present variation are: feed rolls  151  as a work supplying device that supplies a work W through the gap between the lower roll  23  and the upper roll  24 ; and a position sensor  152  configured to detect a position of a front edge of the work W supplied into the gap by the feed rolls  151 . The position sensor  152  is connected to the controlling device  35 . The feed rolls  151  are also configured to be driven by servomotors. 
     In the roll press machine  50  shown in  FIG.  7   , the feed rolls  51  are disposed on an upstream side of the lower roll  23  and the upper roll  24  as seen in a work supplying direction. In contrast, in the roll press machine  150  of the present variation, the feed rolls  151  are disposed on a downstream side of the lower roll  23  and the upper roll  24 . 
     Specifically, the position sensor  152  of the present variation as well as the position sensor  52  shown in  FIG.  7    is a non-contact type displacement gauge disposed at a position of a predetermined basic distance C away from the narrowest position of the gap (corresponding to axes of the lower roll  23  and the upper roll  24 ). When the front edge F of the work W (see  FIG.  8   ) passes through a detection positon of the position sensor  152 , an output of the position sensor  152  is changed depending on a change of the thickness of the work W. Through the detection of the change, it is possible to detect when the front edge F of the work W arrives at the detection position of the position sensor  152 . That is to say, it is possible to detect a position of the front edge F of the work W. 
     On the other hand, if the feed speed of the work W by the feed rolls  151  is obtained, the front edge F of the work W arrives at the narrowest position of the gap at a timing when a time period obtained by dividing the predetermined basic distance C by the feed speed has passed after the front edge F of the work W arrived at the detection position of the position sensor  152 . The feed speed of the work W may be obtained from information about a driving system for the feed rolls  151 , or may be measured by an encoder  153  provided on the feed rollers  151 . 
     As described above for the roll press machine  50  of the second embodiment, the present inventors have found that, at a press-forming for the material in which the plurality of electrode layers having been applied on the metal foil, when the material is supplied as a work W into the gap between the lower roll and the upper roll for consolidating, a concentrated load may be generated at a front edge of the work W. In that case, chipping or crackling may be caused at the material (at the front edge of the material). Furthermore, the present inventors have found that, it is remarkably effective to set the gap to the consolidation gap only after the front edge F of the work W has passed through the narrowest position of the gap by a first predetermined distance, i.e., to maintain the gap larger than the consolidation gap (and larger than the thickness of the work W) until the front edge F of the work W has passed through the narrowest position of the gap by the first predetermined distance, in order to prevent the chipping or crackling at the material (at the front edge of the material). Preferably, the first predetermined distance is selected within a range of 0.001 mm to 3.000 mm, more preferably within a range of 1 mm to 3 mm, although it may depend on the type and/or the thickness of the material. 
     Based on these findings, the controlling device  35  of the present variation controls the electric motors  13  of the electric lifting apparatuses  10  based on the detection results by the position sensor  152  and the feed speed of the work W by the feed rolls  151  obtained in advance in such a manner that the gap is set to the consolidation gap at a timing when the front edge F of the work W has passed through the narrowest position of the gap by the first predetermined distance, i.e., the gap is maintained larger than the consolidation gap (and larger than the thickness of the work W) until the front edge F of the work W has passed through the narrowest position of the gap by the first predetermined distance. 
     In addition, as described above for the roll press machine  50  of the second embodiment, the present inventors have also found that, at a press-forming for the material in which the plurality of electrode layers having been applied on the metal foil, when the material is moved out of the gap between the lower roll and the upper roll for consolidating, a concentrated load may be generated at the work W. In that case, chipping or crackling may be caused at the material. Furthermore, the present inventors have found that, it is remarkably effective to maintain the gap to the consolidation gap until the rear edge R of the work W has arrived at a position of a second predetermined distance toward the narrowest position of the gap, and to set the gap larger than the consolidation gap (and larger than the thickness of the work W) at a timing when the rear edge R of the work W has arrived at the position of the second predetermined distance toward the narrowest position of the gap, in order to prevent the chipping or crackling at the material (at the edge of the material). Preferably, the second predetermined distance is also selected within a range of 0.001 mm to 3.000 mm, more preferably within a range of 1 mm to 3 mm, although it may depend on the type and/or the thickness of the material. 
     In the present variation, when the rear edge R of the work W (see  FIG.  8   ) passes through the detection positon of the position sensor  152  as well, the output of the position sensor  152  is changed depending on a change of the thickness of the work W. Through the detection of the change, it is possible to detect when the rear edge R of the work W arrives at the detection position of the position sensor  152 . 
     Based on these findings, the controlling device  35  of the present variation controls the electric motors  13  of the electric lifting apparatuses  10  based on the detection results by the position sensor  152  and the feed speed of the work W by the feed rolls  151  obtained in advance in such a manner that the gap is maintained to the consolidation gap until the rear edge R of the work W has arrived at the position of the second predetermined distance toward the narrowest position of the gap, and that the gap is set larger than the consolidation gap at a timing when the rear edge R of the work W has arrived at the position of the second predetermined distance toward the narrowest position of the gap. 
     In addition, in the present variation as well, since the lower roll  23  and the upper roll  24  are driven by servomotors, it is possible to synchronize them to the feed roils  151  with high precision. Thereby, it is possible to achieve a feed control of the work W with high precision. 
     In particular, according to the present variation, since the feed rolls  151  are disposed on the downstream side of the lower roll  23  and the upper roll  24 , the work having been consolidated and hardened comes into contact with the feed rolls  51  to be fed by the same. Thus, it is possible to give a sufficient nip pressure to the work W. Therefore, it is remarkably prevented that a slip is generated between the feed rolls  51  and the work W, so that it is possible to achieve a feed control of the work W with higher precision. 
     Furthermore, in the case of the roll press machine  50  shown in  FIG.  7   , there is concern that the work W having relatively low hardness before the consolidation may be undesirably damaged by the feed rolls  51 . However, according to the present variation, it is possible to remove such concern. 
     Moreover, in the present variation as well, when a thermal process is added to the lower roll  23  and the upper roll  24 , the lower roll  23  and the upper roll  24  may be thermally deformed (in particular, diameters thereof may be changed). However, for example by using a temperature detection by a temperature sensor, an appropriate compensation control can be carried out. 
     [Operation of Roll Press Machine  150 ] 
     According to the roll press machine  150  of the present variation as well as the roll press machine  50  of the second embodiment, it is detected by the position sensor  152  that the front edge F of the work W has arrived at the detection position of the position sensor  152 . Then, based on the predetermined basic distance C, the first predetermined distance and the feed speed of the work W, the controlling device  35  controls the electric motors  13  of the electric lifting apparatuses  10  in such a manner that the gap is adjusted to the consolidation gap with high precision at a timing when the front edge F of the work W has passed through the narrowest position of the gap by the first predetermined distance. In other words, until the front edge F of the work W has passed through the narrowest position of the gap by the first predetermined distance, the gap is maintained larger than the consolidation gap (and larger than the thickness of the work W). 
     Thus, it is possible to effectively prevent generation of the concentrated load when the work W is supplied into the gap, and thus it is possible to effectively prevent generation of the chipping or crackling at the front edge of the work W. 
     In addition, according to the roll press machine  150  of the present variation as well as the roll press machine  50  of the second embodiment, it is detected by the position sensor  152  that the rear edge R of the work W has arrived at the detection position of the position sensor  152 . Then, based on the predetermined basic distance C, the second predetermined distance and the feed speed of the work W, the controlling device  35  controls the electric motors  13  of the electric lifting apparatuses  10  in such a manner the gap is maintained to the consolidation gap until the rear edge R of the work W has arrived at the position of the second predetermined distance toward the narrowest position of the gap, and that the gap is set larger than the consolidation gap at a timing when the rear edge R of the work W has arrived at the position of the second predetermined distance toward the narrowest position of the gap. 
     Thus, it is possible to effectively prevent generation of the concentrated load when the work W is moved out of the gap, and thus it is possible to effectively prevent generation of the chipping or crackling at the rear edge of the work W. 
     In the roll press machine  150  of the present variation as well, it is effective to set the consolidation gap to a constant value within a range of 70% to 90% of the thickness of the work W before the consolidation. Alternatively, it is also effective to set the feed speed of the work W to a value within a range of 1 mm/sec to 100 mm/sec and to carry out a cycling operation by fluctuating the consolidation gap within a range of 70% to 110% of the thickness of the work W before the consolidation with a frequency of 1 Hz to 10 Hz (1 to 10 times a second). In the latter case, it is possible to reduce power consumption with respect to a compression rate, at which the material is compressed by the press-forming (consolidating), by about 10%, as described above. 
     [Load Control of Roll Press Machine  50 ,  150 ] 
     As described above, in the roll press machine  50  or  150  as well as in the roll press machine  20 , the lower roll supporting bodies  22  are placed on the second moving bodies  18  of the electric lifting apparatuses  10  via the load cells  21 . By using a change of load values detected by the load cells  21 , it is possible to control the electric motors  13  of the electric lifting apparatuses  10 . 
     The method of controlling the electric motors  13  of the electric lifting apparatuses  10  described above with reference to  FIGS.  7  and  8    uses the detection of the front edge position and the rear edge position of the work W by the position sensor  52  or  152 . Herein, in principle, when there is distortion and/or application unevenness at the front edge portion and the rear edge portion of the work W, a position detection error by the position sensor  52  or  152  may be increased, and thus there may be possibility that the electric motors  13  of the electric lifting apparatuses  10  are not properly controlled. 
     In contrast, the change of load values detected by the load cells  21  is generated by the work W actually coming into contact with the lower roll  23  and/or the upper roll  24 . Thus, according to a method of using this to control the electric motors  13  of the electric lifting apparatuses  10 , even when there is distortion and/or application unevenness at the front edge portion and the rear edge portion of the work W, adverse effects that might be caused thereby are small. 
     More specifically, the present inventors have found that, at a press-forming for the material in which the plurality of electrode layers having been applied on the metal foil, when the material is supplied as a work W into the gap between the lower roll and the upper roll for consolidating, a concentrated load may be generated at a front edge of the work W. In that case, chipping or crackling may be caused at the material (at the front edge of the material). Furthermore, the present inventors have found that, it is remarkably effective to start reducing the gap to the consolidation gap only after the load cells  21  have detected a predetermined load increase per unit time, i.e., to maintain the gap larger than the consolidation gap (but smaller than the thickness of the work W (before the consolidation)) until the load cells  21  have detected a predetermined load increase per unit time, in order to prevent the chipping or crackling at the material (at the front edge of the material). 
     According to the results of the experiments carried out by the present inventors, when the material in which the plurality of electrode layers having been applied on the metal foil is used as a work W, it is effective to set the predetermined load increase per unit time to a value within a range of 100 N/msec to 1000 N/msec, preferably within a range of 100 N/msec to 200 N/msec. 
     Based on these findings, as shown in  FIG.  9   , while the feed rolls  51  or  151  (an example of work supplying device) are driven, the controlling device  35  of the roll press machine  50  or  150  controls the electric motors  13  of the electric lifting apparatuses  10  in such a manner that the gap starts being reduced to the consolidation gap at a timing when the load cells  21  have detected the predetermined load increase per unit time (see  FIG.  9  ( b ) ) (while the feed rolls  51  or  151  continue to be driven) (a state wherein the gap has finished being reduced is shown in  FIG.  9  ( c ) ), i.e., the gap is maintained larger than the consolidation gap (but smaller than the thickness of the work W (before the consolidation)) (see  FIG.  9  ( a ) ) until the load cells  21  have detected the predetermined load increase per unit time. 
     In addition, the present inventors have also found that, at a press-forming for the material in which the plurality of electrode layers having been applied on the metal foil, when the material is moved out of the gap between the lower roll and the upper roll for consolidating, a concentrated load may be generated at the work W. In that case, chipping or crackling may be caused at the material. Furthermore, the present inventors have found that, it is remarkably effective to maintain the gap to the consolidation gap until the load cells  21  have detected a predetermined load decrease per unit time, and to start returning the gap to the original state larger than the consolidation gap (but smaller than the thickness of the work W (before the consolidation)) at a timing when the load cells  21  have detected a predetermined load decrease per unit time, in order to prevent the chipping or crackling at the material (at the edge of the material). 
     According to the results of the experiments carried out by the present inventors, when the material in which the plurality of electrode layers having been applied on the metal foil is used as a work W, it is effective to set the predetermined load decrease per unit time to a value within a range of 100 N/msec to 1000 N/msec, preferably within a range of 100 N/msec to 200 N/msec. 
     Based on these findings, as shown in  FIG.  9   , while the feed rolls  51  or  151  (an example of work supplying device) are driven, the controlling device  35  of the roll press machine  50  or  150  controls the electric motors  13  of the electric lifting apparatuses  10  in such a manner that the gap is maintained to the consolidation gap until the load cells  21  have detected the predetermined load decrease per unit time (see  FIG.  9  ( d ) ), and that the gap starts being returned to the original state larger than the consolidation gap (but smaller than the thickness of the work W (before the consolidation)) at a timing when the load cells  21  have detected the predetermined load decrease per unit time (see  FIG.  9 ( e ) ) (while the feed rolls  51  or  151  continue to be driven) (a state wherein the gap has finished being returned is shown in  FIG.  9  ( e ) ). 
     [Effect of Load Control of Roll Press Machine  50  or  150 ] 
     According to the roll press machine  50  or  150 , when a front edge of a work W arrives at the gap between the lower roll  23  and the upper roll  24  while the feed rolls  51  or  151  are driven, load values detected by the load cells  21  are increased. Then, at a timing when the load cells  21  have detected the predetermined load increase per unit time, the controlling device  35  of the roll press machine  50  or  150  controls the electric motors  13  of the electric lifting apparatuses  10  in such a manner that the gap starts being reduced to the consolidation gap. The gap is maintained larger than the consolidation gap (but smaller than the thickness of the work W (before the consolidation)) until the load cells have detected the predetermined load increase per unit time. 
     By carrying out this control wherein the gap starts being reduced to the consolidation gap at a timing when (only after) the load cells  21  have detected the predetermined load increase per unit time when the work W is supplied into the gap, it is possible to cause a so-called biting of the work W to precede the control. Thereby, it is possible to effectively prevent generation of the concentrated load when the work W is supplied into the gap, and thus it is possible to effectively prevent generation of the chipping or crackling at the front edge portion of the work W. 
     In addition, according to the roll press machine  50  or  150 , when the rear edge of the work W approaches the narrowest position between the lower roll  23  and the upper roll  24  (but has not still passed through the narrowest position) while the feed rolls  51  or  151  are driven, the load values detected by the load cells  21  are decreased. Then, at a timing when the load cells  21  have detected the predetermined load decrease per unit time, the controlling device  35  of the roll press machine  50  or  150  controls the electric motors  13  of the electric lifting apparatuses  10  in such a manner that the gap starts being returned to the original state larger than the consolidation gap (but smaller than the thickness of the work W (before the consolidation)). The gap is maintained to the consolidation gap until the load cells  21  have detected the predetermined load decrease per unit time. 
     By carrying out this control wherein the gap starts being returned to the original state larger than the consolidation gap at a timing when the load cells  21  have detected the predetermined load decrease per unit time when the rear edge of the work W approaches the narrowest position of the gap (but has not still passed through the narrowest position), it is possible to cause this control to precede a so-called moving-out of the work W. Thereby, it is possible to effectively prevent generation of the concentrated load when the work W is moved out of the gap, and thus it is possible to effectively prevent generation of the chipping or crackling at the rear edge portion of the work W. 
     When the above load control is used as well, it is effective to set the consolidation gap to a constant value within a range of 70% to 90% of the thickness of the work W before the consolidation. Alternatively, it is also effective to set the feed speed of the work W to a value within a range of 1 mm/sec to 100 mm/sec and to carry out a cycling operation by fluctuating the consolidation gap within a range of 70% to 110% of the thickness of the work W before the consolidation with a frequency of 1 Hz to 10 Hz (1 to 10 times a second). In the latter case, it is possible to reduce power consumption with respect to a compression rate, at which the material is compressed by the press-forming (consolidating), by about 10%, as described above. 
     As a load sensor which detects loads of the lower roll  23  and/or the upper roll  24 , any other load sensor may be arranged and used at a suitable place, not limited to the load cells  21 . 
     [Structure of Roll Press Machine  60 ] 
     Next,  FIG.  8    is a schematic view of a roll press machine  60  according to a third embodiment of the present invention.  FIG.  11    is a schematic side view of the roll press machine  60  of the present embodiment.  FIG.  12    is a section view taken along line XII-XII of  FIG.  11   . In the roll press machine  60  of the present embodiment, sizes of some components (the lower roll supporting bodies  22 , the upper roll supporting bodies  25 , the roll frame  26 , and the like: see  FIGS.  2  and  9   ) of the roll press machine  50  of the second embodiment are changed, a supporting manner of the upper roll supporting bodies  25  is changed, and backup rolls described below and the like are added. 
     In  FIGS.  10  to  12   , except for the lower roll supporting bodies  22 , the lower roll  23 , the upper roll  24 , the upper roll supporting bodies  25 , the roll frame  26 , the third sliding guides  27 , the feed rolls  51  and the encoder  53 , the components of the roll press machine  50  of the second embodiment are not shown. 
     As shown in  FIGS.  10  to  12   , main components added in the present embodiment are three pairs of upper backup rolls and three pairs of lower backup rolls, i.e., six pairs of backup rolls in total. 
     The present inventors have found that, for a control of maintaining uniform thickness precision of a press-formed work with high precision, it is effective to provide upper-roll backup rolls on an upper surface side of the upper roll  24  to counterbalance an upward deforming (deflecting) force of the upper roll  24  (involving the upper roll supporting bodies  25  and the roll frame  26  which support the upper roll  24 ) produced by a reaction force from a work W at a press-forming, and to provide lower-roll backup rolls on an lower surface side of the lower roll  23  to counterbalance an downward deforming (deflecting) force of the lower roll  23  (involving the lower roll supporting bodies  22  which support the lower roll  23 ) produced by a reaction force from the work W at the press-forming. 
     In addition, the present inventors have found that, as seen in a direction of an axis of the upper roll  24 , the upward deforming (deflecting) force of the upper roll  24  and displacement of the upper roll  24  that may be caused by this force may be different between in a one side area, in a middle area and in the other side area. Similarly, the present inventors have found that, as seen in a direction of an axis of the lower roll  23 , the downward deforming (deflecting) force of the lower roll  23  and displacement of the lower roll  23  that may be caused by this force may be different between in a one side area, in a middle area and in the other side area. Based on these, the present inventors have further found that, it is effective to provide a pair of an upper-roll backup roll and a lower-roll backup roll for each of the one side area, the middle area and the other side area as seen in the directions of the axes of the upper roll  24  and the lower roll  23 , and to independently control a gap between the upper-roll backup roll and the lower-roll backup roll for each pair. 
     Furthermore, the present inventors have found that, it is effective to provide a pair of upper-roll backup rolls on both sides with respect to the axis of the upper roll  24  in a plan view, on the upper surface side of the upper roll  24 , in order to counterbalance the upward deforming force of the upper roll  24  in a well-balanced manner. Similarly, the present inventors have found that, it is effective to provide a pair of lower-roll backup rolls on both sides with respect to the axis of the lower roll  23  in a plan view, on the lower surface side of the lower roll  23 , in order to counterbalance the downward deforming force of the lower roll  23  in a well-balanced manner. 
     Based on these findings, in the roll press machine  60  of the present embodiment, a pair of upper-roll backup rolls is provided for each of the one side area, the middle area and the other side area as seen in the direction of the axis of the upper roll  24 , and a pair of lower-roll backup rolls is provided for each of the one side area, the middle area and the other side area as seen in the direction of the axis of the lower roll  23 . 
     Specifically, in the roll press machine  60  of the present embodiment: a pair of lower-roll one side backup rolls  61   a ,  61   b , each of which and the lower roll  23  roll on each other, is arranged on the lower surface side of the lower roll  23  in the one side area as seen in the direction of the axis of the lower roll  23  (the left side area of  FIG.  12   ); a pair of lower-roll middle backup rolls  62   a ,  62   b , each of which and the lower roll  23  also roll on each other, is arranged on the lower surface side of the lower roll  23  in the middle area as seen in the direction of the axis of the lower roll  23  (the middle area of  FIG.  12   ); and a pair of lower-roll other side backup rolls  63   a ,  63   b , each of which and the lower roll  23  also roll on each other, is arranged on the lower surface side of the lower roll  23  in the other side area as seen in the direction of the axis of the lower roll  23  (the right side area of  FIG.  12   ). 
     In addition, in the roll press machine  60  of the present embodiment: a pair of upper-roll one side backup rolls  64   a ,  64   b , each of which and the upper roll  24  roll on each other, is arranged on the upper surface side of the upper roll  24  in the one side area as seen in the direction of the axis of the upper roll  24  (the left side area of  FIG.  12   ); a pair of upper-roll middle backup rolls  65   a ,  65   b , each of which and the upper roll  24  also roll on each other, is arranged on the upper surface side of the upper roll  24  in the middle area as seen in the direction of the axis of the upper roll  24  (the middle area of  FIG.  12   ); and a pair of upper-roll other side backup rolls  66   a ,  66   b , each of which and the upper roll  24  also roll on each other, is arranged on the upper surface side of the upper roll  24  in the other side area as seen in the direction of the axis of the upper roll  24  (the right side area of  FIG.  12   ). 
     The pair of lower-roll one side backup rolls  61   a ,  61   b  is supported in common by a lower-roll one side backup roll supporting housing  61   h  in such a manner that each of the pair of lower-roll one side backup rolls  61   a ,  61   b  is rotatable. The pair of lower-roll middle backup rolls  62   a ,  62   b  is supported in common by a lower-roll middle backup roll supporting housing  62   h  in such a manner that each of the pair of lower-roll middle backup rolls  62   a ,  62   b  is rotatable. The pair of lower-roll other side backup rolls  63   a ,  63   b  is supported in common by a lower-roll other side backup roll supporting housing  63   h  in such a manner that each of the pair of lower-roll other side backup rolls  63   a ,  63   b  is rotatable. 
     The pair of upper-roll one side backup rolls  64   a ,  64   b  is supported in common by a upper-roll one side backup roll supporting housing  64   h  in such a manner that each of the pair of upper-roll one side backup rolls  64   a ,  64   b  is rotatable. The pair of upper-roll middle backup rolls  65   a ,  65   b  is supported in common by a upper-roll middle backup roll supporting housing  65   h  in such a manner that each of the pair of upper-roll middle backup rolls  65   a ,  65   b  is rotatable. The pair of upper-roll other side backup rolls  66   a ,  66   b  is supported in common by a upper-roll other side backup roll supporting housing  66   h  in such a manner that each of the pair of upper-roll other side backup rolls  66   a ,  66   b  is rotatable. 
     In addition, in the roll press machine  60  of the present embodiment, an electric lifting apparatus  70  is provided as a one side backup rolls adjusting apparatus for causing the lower-roll one side backup roll supporting housing  61   h  and the upper-roll one side backup roll supporting housing  64   h  to move relative to each other, to control a gap between the lower-roll one side backup rolls  61   a ,  61   b  and the upper-roll one side backup rolls  64   a ,  64   b.    
     Similarly, in the roll press machine  60  of the present embodiment, the same electric lifting apparatus  70  is provided as a middle backup rolls adjusting apparatus for causing the lower-roll middle backup roll supporting housing  62   h  and the upper-roll middle backup roll supporting housing  65   h  to move relative to each other, to control a gap between the lower-roll middle backup rolls  62   a ,  62   b  and the upper-roll middle backup rolls  65   a ,  65   b.    
     Furthermore, in the roll press machine  60  of the present embodiment, the same electric lifting apparatus  70  is provided as another side backup rolls adjusting apparatus for causing the lower-roll other side backup roll supporting housing  63   h  and the upper-roll other side backup roll supporting housing  66   h  to move relative to each other, to control a gap between the lower-roll other side backup rolls  63   a ,  63   b  and the upper-roll other side backup rolls  66   a ,  66   b.    
     In the present embodiment, as shown in  FIG.  11   , the upper-roll one side backup roll supporting housing  64   h , the upper-roll middle backup roll supporting housing  65   h  and the upper-roll other side backup roll supporting housing  66   h  are fixed to the roll frame  26 . On the other hand, the upper roll supporting bodies  25  are supported by the roll frame  26  in such a manner that the upper roll supporting bodies  25  are movable up and down by about 1 mm above an anti-drop block  26   c . Specifically, each of the pair of upper roll supporting bodies  25  is provided with pairs of opposite fourth sliding parts  25   s  which are slidably movable relative to the opposite third sliding guides  27 . 
     With respect to the upper-roll one side backup roll supporting housing  64   h , the upper-roll middle backup roll supporting housing  65   h  and the upper-roll other side backup roll supporting housing  66   h , the lower-roll one side backup roll supporting housing  61   h , the lower-roll middle backup roll supporting housing  62   h  and the lower-roll other side backup roll supporting housing  63   h  are independently movable up and down by means of the respective corresponding electric lifting apparatuses  70 . 
     In addition, as shown in  FIG.  11   , each of the lower-roll one side backup roll supporting housing  61   h , the lower-roll middle backup roll supporting housing  62   h  and the lower-roll other side backup roll supporting housing  63   h  is provided with pairs of opposite fourth sliding parts  61   s ,  62   s ,  63   s  which are slidably movable relative to the opposite third sliding guides  27  provided on the roll frame  26 . 
     On the other hand, in the roll press machine  60  of the present embodiment, as shown in  FIG.  10   , the dimension of the consolidated (press-formed) work W in the one side area is measured by a non-contact type distance measuring device  67   a  configured to measure a distance to an upper surface of the one side area of the work W and another non-contact type distance measuring device  67   b  configured to measure a distance to a lower surface of the one side area of the work W. 
     Similarly, the dimension of the consolidated (press-formed) work W in the middle area is measured by a non-contact type distance measuring device  68   a  configured to measure a distance to an upper surface of the middle area of the work W and another non-contact type distance measuring device  68   b  configured to measure a distance to a lower surface of the middle area of the work W. 
     Furthermore, the dimension of the consolidated (press-formed) work W in the other side area is measured by a non-contact type distance measuring device  69   a  configured to measure a distance to an upper surface of the other side area of the work W and another non-contact type distance measuring device  69   b  configured to measure a distance to a lower surface of the other side area of the work W. 
     Then, based on the above respective measurement results, the electric lifting apparatus  70  as the one side backup rolls adjusting apparatus, the electric lifting apparatus  70  as the middle backup rolls adjusting apparatus and the electric lifting apparatus  70  as the other side backup rolls adjusting apparatus are respectively independently controlled by the controlling device  35 . 
     Each of the electric lifting apparatuses  70  of the present embodiment has a similar configuration to that of the electric lifting apparatus  10  configured to cause the lower roll supporting body  22  to move up and down. 
     The different points between them are that the electric lifting apparatus  70  does not have the quadrangular prism  12   e  and the frame ceiling plate  12   g , and that the upper surfaces of the inside frame wall  12   b  and the outside frame wall  12   d  of the electric lifting apparatus  70  are fixed to the lower surface of the roll frame  26 . 
     The other structure of the electric lifting apparatus  70  is substantially the same as the electric lifting apparatus  10 . In the electric lifting apparatus  70 , the same components as those of the electric lifting apparatus  10  are shown by the same reference numerals, and detailed explanation thereof is omitted. 
     Herein, the sizes (dimensions) of the various components of the electric lifting apparatus  70  may be different from those of the corresponding components of the electric lifting apparatus  10 . Assume that a lifting force (pressing force) of the electric lifting apparatus  70  is 200 kN as a nominal value (600 kN for the three left, middle and right ones), a diameter of each roll is 450 mm and a width of each roll is 500 mm. Under this assumption, as an example, a size of the frame bottom plate  12   a  is 15 cm×90 cm in a plan view, and a thickness thereof is about 10 cm, a wall thickness of each of the inside frame wall  12   b  and the outside frame wall  12   d  is about 6 cm, and a height thereof is about 30 cm, a wall thickness of the central frame wall  12   c  is about 6 cm, and a height thereof is about 15 cm. Furthermore, as an example, the motor side pulley  13   p  and the threaded-shaft side pulley  11   p  have a diameter of about 8 cm to 12 cm in common, the motor side pulley  13   p  and the threaded-shaft side pulley  11   p  have a width (thickness) of about 4 cm in common, a width of the belt  14  is slightly narrower than this width and is about 3.5 cm for example, a length of the belt  14  depends on a distance between the axis x of the threaded shaft  11   a  and the output shaft  13   s  of the electric motor  13  and is about 70 to 80 cm for example. In some cases, a reduction gear may be formed by increasing the number of teeth of the threaded-shaft side pulley  11   p  with respect to the number of teeth of the motor side pulley  13   p.    
     According to the above dimensional example, the whole size of the roll press machine  60  is within 180 cm in height×150 cm in width (×90 cm in depth). 
     [Operation of Roll Press Machine  60 ] 
     According to the roll press machine  60  of the present embodiment, each electric lifting apparatus  70  configured to function as a backup rolls adjusting apparatus is compact enough to achieve the configuration (layout) wherein independent backup rolls adjusting apparatuses (electric lifting apparatuses  70 ) are arranged at the three locations, i.e., in the one side area, in the middle area and in the other side area. 
     Then, by controlling the respective electric lifting apparatuses  70  independently, it is possible to finely counterbalance (compensate for) the deforming forces of the upper roll  24  and the lower roll  23  that may be different between in the one side area (the left side area of  FIG.  12   ), in the middle area (the middle area of  FIG.  12   ) and in the other side area (the right side area of  FIG.  12   ), as seen in the directions of the axes of the upper roll  24  and the lower roll  23 . 
     Specifically, in the roll press machine  60  of the present embodiment, the dimension of the consolidated work W in the one side area, the dimension of the consolidated work W in the middle area and the dimension of the consolidated work W in the other side area are actually measured by means of the three sets of the non-contact type distance measuring devices  67   a ,  67   b ,  68   a ,  68   b ,  69   a ,  69   b . Then, based on these measurement results, the electric lifting apparatus  70  as the one side backup rolls adjusting apparatus, the electric lifting apparatus  70  as the middle backup rolls adjusting apparatus and the electric lifting apparatus  70  as the other side backup rolls adjusting apparatus are respectively independently controlled by the controlling device  35  in such a manner that the above dimensions are within an acceptable error range. 
     In addition, in the roll press machine  60  of the present embodiment, in each backup rolls adjusting apparatus (each electric lifting apparatus  70 ), the rotational force of the output shaft  13   s  of the electric motor  13  is used as the rotational force of the threaded shaft  11   a  of the ball screw  11 , and the second moving body  18  moves linearly in the direction perpendicular to the direction of the axis x when the first moving body  15  fixed to the nut  11   d  of the ball screw  11  moves linearly in the direction of the axis x. Thereby, the movement of the second moving body  18  can be controlled with high precision by the electric motor  13 . That is to say, each backup rolls adjusting apparatus (each electric lifting apparatus  70 ) can be controlled with high precision. 
     [Variation of Roll Press Machine  60 ] 
     At least at the time of filing the present application, the present invention includes a manner in which the lower-roll middle backup rolls  62   a ,  62   b , the upper-roll middle backup rolls  65   a ,  65   b , the lower-roll middle backup roll supporting housing  62   h , the upper-roll middle backup roll supporting housing  65   h  and the middle backup rolls adjusting apparatus (the middle electric lifting apparatus  70 ) are not adopted. This manner falls within the scope of claims. 
     To the contrary, if the upper roll  24  and the lower roll  23  are longer in the directions in the axes thereof, the present invention includes a manner adopting two or more sets, each set consisting of: the lower-roll middle backup rolls  62   a ,  62   b ; the upper-roll middle backup rolls  65   a ,  65   b ; the lower-roll middle backup roll supporting housing  62 ; the upper-roll middle backup roll supporting housing  65   h ; and the middle backup rolls adjusting apparatus (one electric lifting apparatus  70 ). This manner also falls within the scope of claims. 
     [First Variation of Electric Lifting Apparatus] 
     In the above embodiments, the rotational force of the output shaft  13   s  of the electric motor  13  is transferred to the threaded shaft  11   a  via the motor side pulley  13   p , the threaded-shaft side pulley  11   p  and the belt  14 . 
     However if it is allowed that the size of the electric lifting apparatus is large to some extent, such as when the width of the rolls is large, the output shaft  13   s  of the electric motor  13  and the threaded shaft  11   a  may be arranged on a straight line. Such a variation is shown in  FIG.  13   . In this variation, the output shaft  13   s  of the electric motor  13  and the threaded shaft  11   a  are coupled to each other via a coupling  13   c.    
     In the present first variation, the size of the electric lifting apparatus is larger than those of the above described electric lifting apparatuses  10 ,  70 , but maintenance performance thereof is better. 
     At least at the time of filing the present application, even in the case wherein the motor side pulley  13   p , the threaded-shaft side pulley  11   p  and the belt  14  are used, it is not intended to limit to the manner wherein the output shaft  13   s  of the electric motor  13  and the threaded shaft  11   a  are arranged in the vertical direction, i.e., it is not excluded that the output shaft  13   s  of the electric motor  13  and the threaded shaft  11   a  are arranged in a horizontal direction (right and left direction). 
     In addition, the outside bearing  11   c  configured to support the threaded shaft  11   a  of the ball screw  11  may be buried in the outside frame wall  12   d , instead of in the central frame wall  12   c . In this case, the central frame wall  12   c  may be omitted, which may make the electric lifting apparatus more compact. 
     [Structure of Second Variation of Electric Lifting Apparatus] 
       FIG.  14    is a schematic front view showing a roll press machine including a second variation of the electric lifting apparatus,  FIG.  15    is a schematic side view of the roll press machine shown in  FIG.  14   , and  FIG.  16    is a section view taken along line XVI-XVI of the roll press machine shown in  FIG.  14   . 
     As shown in  FIG.  14   , the electric lifting apparatus  110  of the second variation includes a ball screw  111 . The ball screw  111  has: a threaded shaft  111   a  having an axis x; a pair of bearings  111   b ,  111   c  provided at both end parts of the threaded shaft  111   a  and configured to support the threaded shaft  111   a  in such a manner that the threaded shaft  111   a  is rotatable around the axis x; and a nut  111   d  threadedly engaged with the threaded shaft  111   a  via a plurality of rolling elements (not shown) in such a manner that the nut  111   d  moves linearly in a direction of the axis x when the threaded shaft  111   a  rotates. 
     As well as the axis x of the threaded shaft  11   a  of the electric lifting apparatus  10 , the axis x of the threaded shaft  111   a  is also parallel to the axis of the lower roll  23  (one side roll) and the axis of the upper roll  24  (the other side roll). The bearing  111   c  (two juxtaposed bearings) on the roll side (on the inner side) is buried in (supported by) an inside frame wall  112   c . The bearing  111   b  on the opposite side (on the outer side) is buried in (supported by) an outside frame wall  112   b . The inside frame wall  112   c  and the outer frame wall  112   b  are erected on an upper surface of a plate-like frame bottom plate  112   a.    
     With reference to  FIGS.  14  and  15    (and further with reference to  FIG.  2   ), a lower surface of the frame bottom plate  112   a  is supported by a lower part  26   a  of a roll frame  26 . In addition, an electric motor mounting plate  112   f , which has a L-shaped section, is fixed to an upper surface of the frame bottom plate  112   a  inner than the inside frame wall  112   c.    
     A frame  112  is formed by the frame bottom plate  112   a , the outside frame wall  112   b , the inside frame wall  112   c , a central frame wall  112   d  described below and the electric motor mounting plate  112   f . These components of the frame  112  may be integrally formed, or may be separately formed and subsequently fixed to each other. 
     As shown in  FIG.  14   , an electric motor  113  having an output shaft  113   s  being rotatable (preferably a servomotor) is fixed to the electric motor mounting plate  112   f . The output shaft  113   s  of the electric motor  113  is aligned on a straight line along the axis x of the threaded shaft  111   a  of the ball screw  111 . In the present variation, the output shaft  113   s  of the electric motor  113  and the threaded shaft  11   a  are coupled to each other via a coupling  113   c.    
     A first moving body  115  is fixed to the nut  111   d  of the ball screw  111  and is movable integrally with the nut  111   d . The first moving body  115  has a first sliding surface  115   t  inclined at a predetermined angle with respect to a plane (a horizontal plane in the present variation) including the direction of the axis x of the threaded shaft  111   a.    
     In addition, as clearly seen from  FIG.  14   , the threaded shaft  111   a  extends through the first moving body  115  in the direction of the axis x. The pair of bearings  111   b ,  111   c  is arranged on both sides of the first moving body  115 . 
     A first sliding guide  116 , which extends in parallel with the direction of the axis x, is provided on the upper surface of the frame bottom plate  112   a . The first moving body  115  is provided with a first sliding part  115   s  which is slidably movable relative to the first sliding guide  116 . Slidable surfaces of the first sliding guide  116  and the first sliding part  115   s  extend in parallel with the direction of the axis x of the threaded shaft  111   a  in a plan view. 
     In the present variation, as shown in  FIG.  15   , the first sliding part  115   s  extends in parallel with the direction of the axis x of the threaded shaft  111   a , but in a position offset therefrom in a plan view. In addition, as shown in  FIG.  15   , the first sliding surface  115   t  also extends in parallel with the direction of the axis x of the threaded shaft  111   a , but in a position offset therefrom in a plan view. The first sliding surface  115   t  and the first sliding part  115   s  are arranged in such a manner they are almost overlapped with each other in a plan view. 
     In addition, the electric lifting apparatus  110  has a second moving body  118  arranged to be movable linearly in a direction (a vertical direction in the present variation) perpendicular to the direction of the axis x with respect to the frame  112 . The second moving body  118  has a second sliding surface  118   t , which is slidably movable relative to the first sliding surface  115   t . Thereby, the second moving body  118  is caused to move linearly in the above perpendicular direction by a sliding movement between the first sliding surface  115   t  and the second sliding surface  118   t  when the nut  111   d  and the first moving body  115  moves linearly in the direction of the axis x. 
     In addition, in the present variation, as shown in  FIG.  15   , the first sliding surface  115   t  and the second sliding surface  118   t  are arranged in such a manner that they are almost overlapped with the slidable surfaces of the first sliding guide  116  and the first sliding part  115   s  in a plan view. That is to say, the second sliding surface  118   t  extends in parallel with the direction of the axis x of the threaded shaft  111   a , but in a position offset therefrom in a plan view. Furthermore, in the present variation, as shown in  FIG.  16   , the whole second moving body  118  extends in parallel with the direction of the axis x of the threaded shaft  111   a , but in a position offset therefrom in a plan view. 
     As a specific structural example, the pair of the first sliding surface  115   t  and the second sliding surface  118   t  may be provided by a general linear guide. That is to say, with reference to  FIG.  15   , the first sliding surface  115   t  may be provided as a concave surface, whose section has a concave shape, of a member which is called “block” of the linear guide, and the second sliding surface  118   t  may be provided as a lower surface, whose section has a rectangular shape, of a member which is called “rail” of the linear guide. For example, a commercially available linear guide may be disassembled, and subsequently a “block” thereof may be fixed to an upper surface of a main body of the first moving body  115  and a “rail” thereof may be fixed to a lower surface of a main body of the second moving body  118 , which may result in that the pair is arranged. 
     As shown in  FIGS.  14  to  16   , the second moving body  118  is provided with a second sliding part  118   s  which extends in the perpendicular direction (the direction perpendicular to the direction of the axis x, i.e., the vertical direction in the present variation), and the second sliding part  118   s  is slidably movable relative to a second sliding guide  119  which extends in the same direction. The second sliding guide  119  is fixed to a central frame wall  112   d  fixed to an upper surface of the frame bottom plate  112   a . In addition, in the present variation, a load cell  21  is provided on an upper surface of the second moving body  118 . 
     The roll press machine shown in  FIGS.  14  to  16    includes a pair of the above described electric lifting apparatuses  110 . As shown in  FIG.  16   , in the pair of electric lifting apparatuses  110 , the frame bottom plate  112   a  and the central frame wall  112   d  are arranged as common members. Each of the second sliding guides  119  is fixed on each of the left and right sides of the central frame wall  112   d.    
     In the roll press machine shown in  FIGS.  14  to  16    as well as in the roll press machine  20  shown in  FIGS.  1  and  2   , a pair of lower roll supporting bodies  22  (one side roll supporting parts) are respectively supported by the pair of second moving bodies  118  of the pair of electric lifting apparatuses  110 . Each of the pair of lower roll supporting bodies  22  is placed on the corresponding second moving body  118  via the load cell  21 . The pair of lower roll supporting bodies  22  has bearings configured to support a lower roll  23  in such a manner that the lower roll  23  is rotatable. 
     An upper roll  24  is arranged opposite to the lower roll  23 . A press forming (consolidating) of a work W is carried out by using a gap formed between the lower roll  23  and the upper roll  24 . 
     The upper roll  24  is supported by a pair of upper roll supporting bodies  25  (the other side roll supporting parts) in such a manner that the upper roll  24  is rotatable. Each of the pair of upper roll supporting bodies  25  is fixed to each of a pair of roll frames  26  provided on a base  140 , for example via bolt screws or the like not shown from outside. 
     As a dimensional example of each element, when a lifting force (pressing force) of the electric lifting apparatus  110  is 300 kN as a nominal value (600 kN for a pair of right and left ones) and a diameter of each roll is 450 mm, a size of the frame bottom plate  112   a  is 110 cm (length seen in  FIG.  14   )×50 cm (length seen in  FIG.  15   ) in a plan view, and a thickness thereof is about 5 cm. 
     In the electric lifting apparatus  110  of the second variation as well as in the electric lifting apparatus  10 , the predetermined angle of the first sliding surface  115   t  may be selected within a range of 5.7 degrees to 11.3 degrees. The “5.7 degrees” is the solution of tan θ=1/10. The “11.3 degrees” is the solution of tan θ=1/5. Thus, a leverage ratio (lever mechanism ratio) of 5 to 10 times can be achieved. 
     Through the practical verification experiments carried out by the present inventors, it has been confirmed that the electric lifting apparatus  110  of the second variation is effectively operable within the above angle range. 
     A moving stroke of the second moving body  118  may be 1 mm, which is enough for an application as described below (an application in which a material consisting of a plurality of electrode layers having been baked on a metal foil is used as a work W). 
     A moving speed of the second moving body  118  may be 10 mm/sec, for example, which corresponds to a moving speed of the first moving body  115  (i.e., the nut  111   d ) of 50 mm/sec when the leverage ratio is 5 times, or a moving speed of the first moving body  115  (i.e., the nut  111   d ) of 100 mm/sec when the leverage ratio is 10 times. Such a moving speed of the nut  111   d  can be achieved by a commercially available general electric motor  113  and a commercially available general ball screw  111 . In particular, when the electric motor  113  is a servomotor, a control with higher precision and higher responsivity can be achieved. 
     [Operation of Electric Lifting Apparatus  110 ] 
     Next, an operation of the electric lifting apparatus  110  of the second variation is explained. 
     When the electric motor  113  is driven in a desired manner (for example, the electric motor  113  may be controlled by the controlling device  35  as described above), the output shaft  113   s  of the electric motor  113  rotates. Subsequently, via the coupling  113   c , a rotational force of the output shaft  113   s  is transferred to a rotational force of the threaded shaft  111   a . Subsequently, a rotation of the threaded shaft  111   a  is converted to a linear movement of the nut  111   d  in the direction of the axis x by a converting function of the ball screw  11   l  between the rotational movement and the linear movement. 
     Thereby, the first moving body  115  fixed to the nut  111   d  moves linearly in the direction of the axis x. Herein, the linear movement of the first moving body  115  in the direction of the axis x is smoothly achieved because of an interaction between the first sliding guide  116  and the first sliding part  115   s  (a facilitating action of a smooth sliding movement). 
     Subsequently, when the nut  111   d  and the first moving body  115  move linearly in the direction of the axis x, the second moving body  118  moves linearly in the direction perpendicular to the direction of the axis x, by a sliding movement between the first sliding surface  115   t  and the second sliding surface  118   t . Herein, the linear movement of the second moving body  118  is smoothly achieved because of an interaction between the second sliding guide  119  and the second sliding part  118   s  (a facilitating action of a smooth sliding movement). 
     Herein, as shown in  FIG.  16   , since the pair of second moving bodies  118  are arranged in a well-balanced manner with respect to the pair of threaded shafts  111   a , the linear movement (horizontal movement) of the pair of first moving bodies  115  can be converted to the linear movement (up and down movement) of the pair of second moving bodies  18  in a well-balanced manner, and a load (reaction force) received by the second moving bodies  118  can be also supported by the base  140  via the first moving bodies  115   t  and so on in a well-balanced manner. 
     In addition, when the electric motor  113  is driven in a desired manner, the movement of the second moving body  118  can be controlled in a desired manner with high precision. In particular, when the electric motor  113  is a servomotor, a control with higher precision and higher responsivity can be achieved. 
     [Effects of Electric Lifting Apparatus  110 ] 
     As described above, according to the electric lifting apparatus  110  of the second variation as well, the rotational force of the output shaft  113   s  of the electric motor  113  is used as the rotational force of the threaded shaft  111   a  of the ball screw  111 , and the second moving body  118  moves linearly in the direction perpendicular to the direction of the axis x when the first moving body  115  fixed to the nut  111   d  of the ball screw  111  moves linearly in the direction of the axis x. Thereby, the movement of the second moving body  118  can be controlled with high precision by the electric motor  113 . 
     In addition, according to the electric lifting apparatus  110  of the second variation as well, since the threaded shaft  111   a  extends through the first moving body  115  in the direction of the axis x and the pair of bearings  111   b ,  111   c  is arranged on the both sides of the first moving body  115 , the whole electric lifting apparatus  110  is compact. 
     In addition, according to the electric lifting apparatus  110  of the second variation, since the output shaft  113   s  of the electric motor  113  and the threaded shaft  111   a  are coupled in a simple manner via the coupling  113   c , maintenance performance thereof is better. 
     Furthermore, since a hydraulic system is not adopted, i.e., since there is no concern about pollution of the surrounding by oil, the electric lifting apparatus  110  of the second variation is also suitable to be displaced in a glove box. 
     In addition, according to the electric lifting apparatus  110  of the second variation as well, the frame  112  is provided with the first sliding guide  116  which extends in parallel with the direction of the axis x, and the first moving body  115  is provided with the first sliding part  115   s  which is slidably movable relative to the first sliding guide  116 . Thereby, because of the interaction therebetween (the facilitating action of the smooth sliding movement), the movement of the first moving body  115  in the direction of the axis x is more smoothly achieved. 
     In addition, according to the electric lifting apparatus  110  of the second variation as well, the frame  112  is provided with the second sliding guide  119  which extends perpendicularly to the direction of the axis x, and the second moving body  118  is provided with the second sliding part  118   s  which is slidably movable relative to the second sliding guide  119 . Thereby, because of the interaction therebetween (the facilitating action of the smooth sliding movement), the movement of the second moving body  118  in the direction perpendicular to the direction of the axis x is more smoothly achieved. 
     In addition, according to the electric lifting apparatus  110  of the second variation, the first sliding part  115   s  extends in parallel with the direction of the axis x of the threaded shaft  111   a  but in the position offset therefrom in a plan view, the first sliding surface  115   t  also extends in parallel with the direction of the axis x of the threaded shaft  111   a  but in the position offset therefrom in a plan view, the first sliding surface  115   t  and the first sliding part  115   s  are arranged in such a manner they are almost overlapped with each other in a plan view, and the whole second moving body  118  extends in parallel with the direction of the axis x of the threaded shaft  111   a  but in the position offset therefrom in a plan view. Thereby, the whole combination of the first sliding surface  115   t , the first sliding part  115   s  and the second moving body  118  can be arranged in a position offset from the electric motor  113 , which can contribute to making the apparatus layout more compact. 
     In addition, in the roll press machine shown in  FIGS.  14  to  16   , the pair of second sliding guides  119  of the pair of electric lifting apparatuses  110  are supported by the common frame wall  112   d . This also contributes to making the apparatus layout more compact. 
     [Third Variation of Electric Lifting Apparatus] 
       FIG.  17    is a schematic side view of a third variation of the electric lifting apparatus. 
     In the third variation, as shown in  FIG.  17   , instead of the one first sliding surface  115   t  in the second variation, two first sliding surfaces  215   t  are provided. Each of the two first sliding surfaces  215   t  extends in the direction of the axis x of the threaded shaft  111   a , as well as the first sliding surface  115   t.    
     Correspondingly, in the third variation, as shown in  FIG.  17   , instead of the one second sliding surface  118   t  in the second variation, two second sliding surfaces  218   t  are provided. Each of the two second sliding surfaces  218   t  also extends in the direction of the axis x of the threaded shaft  111   a , as well as the second sliding surface  118   t.    
     Furthermore, in the third variation, as shown in  FIG.  17   , instead of the one first sliding part  115   s  in the second variation, two first sliding parts  215   s  are provided. Each of the two first sliding parts  215   s  also extends in the direction of the axis x of the threaded shaft  111   a , in the same way as the first sliding part  115   s.    
     Correspondingly, in the third variation, as shown in  FIG.  17   , instead of the one first sliding guide  116  in the second variation, two first sliding guides  216  are provided. Each of the two first sliding guides  216  also extends in the direction of the axis x of the threaded shaft  111   a , as well as the first sliding guide  116 .