Abstract:
A supporting device according to the embodiment comprises a linear guide and a mounting base configured to move linearly, guided by the linear guide, a movable portion mounted on the mounting base, a servomotor having a ball screw which causes the mounting base to move the movable portion linearly, and a plurality of wedges located between the movable portion and the mounting base in front of and/or at the back of the movable portion and configured to adjust inclinations of the movable portion in an up-down direction and in a left-right direction within a horizontal plane.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is based upon and claims the benefit of priority from prior Japanese Patent Application No. 2005-112504, filed Apr. 8, 2005, the entire contents of which are incorporated herein by reference.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to a movable portion supporting device for supporting a movable die and a die clamping unit, in an injection molding machine or the like in which a liquid resin is injected into injection molding dies to form a molded product.  
         [0004]     2. Description of the Related Art  
         [0005]      FIGS. 8 and 9  show an example of an injection molding machine in which a liquid resin is injected into injection molding dies to form a molded product. This injection molding machine comprises a die clamping frame  41 , a stationary portion  43 , a movable portion  45 , and a movable die  46 . The stationary portion  43  is provided on the upper surface of the frame  41  and fitted with a stationary die  42 . The movable portion  45  is attached to the stationary portion  43  for advance and retreat by tie bars  44 . The movable die  46  is provided on the movable portion  45  for advance and retreat with respect to the stationary die  42 .  
         [0006]     Slide plates  47 , which are formed of a belt-shaped steel plate with low frictional resistance each, are provided individually on the opposite sides, left and right, of the upper surface of the die clamping frame  41 . The slide plates  47  support the movable portion  45  for linear movement in a Z-axis direction by means of wedge holders  48 . Further, hydraulic cylinders  49  are located individually on the opposite sides of die clamping frame  41 . Respective rods  50  of the cylinders  49  are coupled individually to the opposite side portions of the wedge holders  48  that support the movable portion  45 . In a die clamping operation, the hydraulic cylinders  49  cause the movable portion  45  to move the movable die  46 , whereby a die clamping force for the stationary die  42  can be obtained.  
         [0007]     The wedge holders  48  extend in the die opening and closing direction and are fixed. The holders  48  receive a moment to urge the movable portion  45  to fall, thereby keeping the movable portion  45  parallel to the stationary portion  43  as the dies are opened or closed.  
         [0008]     The respective rods  50  of the hydraulic cylinders  49  are coupled to the lower end part of the movable portion  45 . If the movable portion  45  is moved by the cylinders  49 , thereby clamping the movable die  46  to the stationary die  42 , therefore, the movable portion  45  inclines in an up-down direction. If the pair of hydraulic cylinders  49  are driven with a time lag, moreover, the movable portion  45  inclines in a left-right direction (vertical direction of  FIG. 8 ). If the hydraulic cylinders  49  move the movable portion  45  with a strong force so that the movable die  46  is clamped to the stationary die  42 , furthermore, the outer peripheral edge of the movable portion  45  is deformed toward the stationary portion  43 . On the other hand, the outer peripheral edge of the stationary portion  43  is deformed toward the movable portion  45 . Thus, each of the stationary and movable portions  43  and  45  is deformed substantially into the shape of a circular arc as viewed both laterally and flat.  
         [0009]     In consideration of these circumstances, a technique is proposed such that wedges are used as means for adjusting the stationary and movable portions  43  and  45  to be parallel to each other, thereby smoothing die opening and closing strokes to prevent breakage or abrasion of the dies.  
         [0010]     More specifically, as also shown in  FIGS. 10 and 11 , first wedges  51   a  and  51   b  are located on respective lower surfaces  48   a  of the left- and right-hand wedge holders  48 , respectively, in front of the movable portion  45 . Further, second wedges  52   a  and  52   b  are located at the back of the movable portion  45 . The first wedges  51   a  and  51   b  and the second wedges  52   a  and  52   b  are inserted between the slide plates  47  and the wedge holders  48 . By adjusting the depth of insertion of the first wedges  51   a  and  51   b  , therefore, the movable portion  45  can be inclined in a rotation direction around the Z-axis and a rotation direction around an X-axis. Likewise, by adjusting the depth of insertion of the second wedges  52   a  and  52   b  , the movable portion  45  can be inclined in the rotation direction around the Z-axis and the rotation direction around the X-axis. Thus, the movable portion  45  and the stationary portion  43  can be kept parallel to each other to smooth the die opening and closing strokes and protect the dies. Furthermore, the sliding resistance between the movable portion  45  and the tie bars  44  can be regulated by simultaneously adjusting the depths of insertion of the first wedges  51   a  and  51   b  and the second wedges  52   a  and  52   b  and moving the movable portion  45  up and down in the direction of a Y-axis.  
         [0011]     Further, third wedges  53   a  and  53   b are located on respective side surfaces  48   b  of the left- and right-hand wedge holders  48 , respectively, in front of the movable portion  45 , and fourth wedges  54   a  and  54   b  at the back. The third wedges  53   a  and  53   b and the fourth wedges  54   a  and  54   b  are inserted between the slide plates  47  and the wedge holders  48 . By adjusting the depth of insertion of the third wedges  53   a  and  53   b , therefore, the movable portion  45  can be inclined in a rotation direction around the Y-axis. Likewise, by adjusting the depth of insertion of the fourth wedges  54   a  and  54   b , the movable portion  45  can be inclined in the rotation direction around the Y-axis. Thus, the parallelism with the stationary portion  43  can be maintained to smooth the die opening and closing strokes and protect the dies.  
         [0012]     In the injection molding machine described above, the movable portion  45  can be inclined in the rotation direction around the X-axis by adjusting the depth of insertion of the first wedges  51   a  and  51   b . At the same time, however, the movable portion  45  also moves in the Y-axis direction, so that its height changes inevitably. Thus, in the aforementioned arrangement, the movement of the movable portion  45  in the Y-axis direction and the X-axis rotation thereof cannot be adjusted independently of each other.  
         [0013]     This invention has been made in consideration of these circumstances, and its object is to provide a supporting device for a movable portion and a die clamping unit, configured so that a movable portion can be easily, independently adjusted in an up-down direction and a left-right direction.  
       BRIEF SUMMARY OF THE INVENTION  
       [0014]     A supporting device for a movable portion according to an aspect of the present invention comprises: a linear guide and a mounting base configured to move linearly, guided by the linear guide; the movable portion mounted on the mounting base; a servomotor having a ball screw which causes the mounting base to move the movable portion linearly; and a plurality of adjusting mechanism located between the movable portion and the mounting base in front of and/or at the back of the movable portion and configured independently to adjust inclinations of the movable portion in an up-down direction and in a left-right direction within a horizontal plane.  
         [0015]     In a supporting device for a movable portion according to another aspect of the invention, the adjusting mechanisms are wedges which are inserted between the movable portion and the mounting base and serve to adjust the inclinations of the movable portion in the up-down direction and in the left-right direction within the horizontal plane, depending on the depth of the insertion.  
         [0016]     In a supporting device for a movable portion according to a further aspect of the invention, the adjusting mechanisms include wedges which are inserted between the movable portion and the mounting base and serve to adjust the inclinations of the movable portion in the up-down direction and in the left-right direction within the horizontal plane, depending on the depth of the insertion, and elastic pressure members which are opposed to the wedges and elastically press the movable portion toward the mounting base.  
         [0017]     In a supporting device for a movable portion according to a further aspect of the invention, the wedges include first and second wedges which are located individually in front and at the back of the movable portion and serve to adjust the inclination of the movable portion in the up-down direction and third wedge which are located in front or at the back of the movable portion and serve to adjust the inclination of the movable portion and in the left-right direction within the horizontal plane.  
         [0018]     A supporting device for a movable portion according to an additional aspect of the invention includes die clamping means having a stationary portion fitted with a stationary die and a movable portion attached to the stationary portion by a tie bar and configured to move the movable portion to advance or retreat a movable die fixed to the movable portion with respect to the stationary die, thereby generating a die clamping force, comprising: a linear guide and a mounting base configured to move linearly, guided by the linear guide; the movable portion mounted on the mounting base; a servomotor having a ball screw which causes the mounting base to move the movable portion linearly; and a plurality of adjusting mechanism located between the movable portion and the mounting base in front of and/or at the back of the movable portion and configured independently to adjust inclinations of the movable portion in an up-down direction and in a left-right direction within a horizontal plane.  
         [0019]     A supporting device for a movable portion according to another aspect of the invention has the movable portion which is mounted on a mounting base configured to move linearly, guided by a linear guide, and is supported for linear movement by a servomotor having a ball screw, comprising a plurality of adjusting mechanism located between the movable portion and the mounting base in front of and/or at the back of the movable portion and configured independently to adjust inclinations of the movable portion in an up-down direction and in a left-right direction within a horizontal plane.  
         [0020]     Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter. 
     
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING  
       [0021]     The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention, and together with the general description given above and the detailed description of the embodiments given below, serve to explain the principles of the invention.  
         [0022]      FIG. 1  is a side view of a die clamping unit of a hybrid injection molding machine according to a first embodiment of the invention;  
         [0023]      FIG. 2  is a plan view of the die clamping unit of the embodiment;  
         [0024]      FIG. 3  is a sectional view of the embodiment taken along line A-A of  FIG. 1 ;  
         [0025]      FIG. 4A  is a plan view of a wedge mechanism of the embodiment;  
         [0026]      FIG. 4B  is a side view of the wedge mechanism of the embodiment;  
         [0027]      FIG. 5A  is a plan view of the wedge mechanism of the embodiment;  
         [0028]      FIG. 5B  is a side view of the wedge mechanism of the embodiment;  
         [0029]      FIG. 6  is a side view of a first elastic pressure member of the embodiment;  
         [0030]      FIG. 7  is a plan view of a second elastic pressure member of the embodiment;  
         [0031]      FIG. 8  is a plan view of a die clamping unit of a conventional injection molding machine;  
         [0032]      FIG. 9  is a side view of the die clamping unit of the conventional injection molding machine;  
         [0033]      FIG. 10  is a view taken in the direction of arrow B of  FIG. 8 ; and  
         [0034]      FIG. 11  is a view taken in the direction of arrow C of  FIG. 8 . 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0035]     An embodiment of this invention will now be described with reference to the accompanying drawings.  
         [0036]     FIGS.  1  to  7  show a first embodiment, in which  FIG. 1  is a side view of a die clamping unit of a hybrid injection molding machine,  FIG. 2  is a plan view, and  FIG. 3  is a sectional view taken along line A-A of  FIG. 1 .  
         [0037]     As shown in FIGS.  1  to  3 , a die clamping frame  1  is provided with a stationary portion  2  and a movable portion  3 . A stationary die  4  is attached to the stationary portion  2 . The movable portion  3  is fitted with a movable die  5 , which faces the stationary die  4 . A plurality of tie bars  6  protrude from the stationary portion  2 . The tie bars  6  support the movable portion  3  for advance and retreat with respect to the stationary portion  2 .  
         [0038]     A pair of linear guides  7 , left and right, are provided on the die clamping frame  1 . The linear guides  7  individually support a pair of mounting bases  8  for linear movement. A separate movable portion supporting member  9  is movably mounted on each mounting base  8 . The movable portion  3  is fixed to the supporting members  9 . Thus, the mounting bases  8  are guided individually by the linear guides  7  as they move linearly. The movable portion  3  and the movable portion supporting members  9  are integral with one another and are guided by the tie bars  6  as they move linearly.  
         [0039]     Servomotors  10  are located individually on the left- and right-hand sides of the die clamping frame  1 . The respective rotating shafts of the servomotors  10  are provided individually with thread portions  11  that extend parallel to the pair of linear guides  7 . A nut portion  12  is threadedly fitted on each thread portion  11 , thereby forming a ball screw  13 . The nut portion  12  of each ball screw  13  is fixed to a mounting portion  14  that protrudes integrally outward from each mounting base  8 .  
         [0040]     When rotary motions of the servomotors  10  are converted into linear motions by the ball screws  13 , therefore, the mounting bases  8  linearly move, guided by the linear guides  7 . Further, the movable portion  3  and the movable portion supporting members  9  on the mounting bases  8  also linearly move in a body, guided by the tie bars  6 .  
         [0041]     First wedges  15  and second wedges  16  are provided between the mounting bases  8  and the movable portion supporting members  9 . They serve as adjustment mechanisms for adjusting vertical inclinations of the supporting members  9  with respect to the mounting bases  8 . Further, third wedges  17  are provided as adjusting mechanisms for adjusting transverse inclinations.  
         [0042]     The first to third wedges  15  to  17  have basically the same construction shown in  FIGS. 4 and 5 . Each wedge body  18  is provided with an insert portion  19  that has a slope  19   a.  A raised portion  20  is provided integrally on the proximal end part of the insert portion  19 . First and second threaded holes  21  and  22  are bored through the raised portion  20 . A first bolt  23  is screwed in the first threaded hole  21 . The distal end of the bolt  23  abuts against a sidewall of each supporting member  9 . A second bolt  24  is screwed in the second threaded hole  22 . A threaded portion  24   a  of the bolt  24  is screwed in a threaded hole  24   b  in the sidewall of the supporting member  9 .  
         [0043]     Thus, if the first and second bolts  23  and  24  are loosened and screwed in, respectively, as shown in  FIG. 4 , the wedge body  18  advances with respect to the movable portion supporting member  9 . If the second and first bolts  24  and  23  are loosened and screwed in, respectively, as shown in  FIG. 5 , on the other hand, the wedge body  18  retreats with respect to the supporting member  9 .  
         [0044]     As shown in FIGS.  1  to  3 , moreover, the first wedges  15  are provided between the left- and right-hand mounting bases  8  and the movable portion supporting members  9  in front of the movable portion  3 . Further, the second wedges  16  are provided between the mounting bases  8  and the supporting members  9  at the back of the movable portion  3 . Accordingly, the vertical inclinations of the supporting members  9  with respect to the mounting bases  8  can be adjusted by the first and second wedges  15  and  16 . Furthermore, each third wedge  17  is provided between a vertical surface  8   a  of each mounting base  8  and a vertical surface  9   a  of each supporting member  9 . The third wedges  17  are located at right angles to the first and second wedges  15  and  16 . Thus, the transverse inclinations of the supporting members  9  with respect to the mounting bases  8  can be adjusted by the third wedges  17 .  
         [0045]     A first elastic pressure member  25  is provided on the upper surface of each movable portion supporting member  9  that faces each first wedge  15 . The pressure member  25  elastically presses the supporting member  9  toward each mounting base  8 . As shown in  FIG. 6 , a spring holder  26  is fixed to the mounting base  8 . The spring holder  26  is provided with a spring storage portion  27  in the form of a vertical depression that faces the upper surface of the supporting member  9 . The spring storage portion  27  contains a pressure piston  28  and a plurality of coned disc springs  29 . The springs  29  are kept compressed by a lid  30  that closes the spring storage portion  27 . Thus, the pressure piston  28  elastically presses a load receiving surface  9   b  of the supporting member  9  by means of the elastic force of the springs  29 . In consequence, the left- and right-hand supporting members  9  are downwardly pressed against their corresponding mounting bases  8  by the springs  29 .  
         [0046]     Further, a second elastic pressure member  31  is provided on the front part of each mounting base  8 . The pressure member  31  elastically presses each movable portion supporting member  9  rearward or toward its corresponding third wedge  17  so as to face the wedge  17 . As shown in  FIG. 7 , moreover, an L-shaped patch  32  is fixed to the mounting base  8 . The patch  32  is provided with the load receiving surface  9   b  that faces the front face of the supporting member  9 .  
         [0047]     Each movable portion supporting member  9  is provided with a spring storage portion  33  in the form of a longitudinal depression. The spring storage portion  33  contains a pressure piston  34  and a plurality of coned disc springs  35 . The springs  35  are kept compressed by a lid  36  that closes the spring storage portion  33 . Thus, the pressure piston  34  elastically presses the load receiving surface  9   b  of the supporting member  9  by means of the elastic force of the springs  35 . In consequence, the left- and right-hand supporting members  9  are transversely pressed against their corresponding mounting bases  8  by the springs  35 .  
         [0048]     The first and second elastic pressure members  25  and  31  are arranged in pairs, left and right, between the mounting bases  8  and the movable portion supporting members  9 . They serve to absorb vertical and transverse deformations, if any, of the movable portion  3 . Thus, while the movable portion  3  is allowed to move linearly by means of linear guides  7 , it is elastically supported in the left-right and up-down directions by the pressure members  25  and  31  in the vicinity of the linear guides  7 . If the movable portion  3  is subjected to any deformations, the deformations are absorbed, so that their influences on the movable portion  3 , stationary and movable dies  4  and  5 , and linear guides  7  can be reduced.  
         [0049]     The following is a description of the operation of the die clamping unit of the injection molding machine constructed in this manner.  
         [0050]     The inclination of the movable portion supporting members  9  in an up-down direction α with respect to the mounting bases  8  can be adjusted by the first and second wedges  15  and  16 . If the first and second bolts  23  and  24  are loosened and screwed in, respectively, the wedge bodies  18  advance with respect to the movable portion supporting members  9 . If the second and first bolts  24  and  23  are loosened and screwed in, respectively, in contrast with this, the wedge bodies  18  retreat with respect to the supporting members  9 .  
         [0051]     Thus, the inclination of the movable portion supporting members  9  in the up-down direction a can be adjusted by the first and second wedges  15  and  16 . Likewise, the left- and right-hand third wedges  17  can adjust the inclination of the supporting members  9  in a left-right direction β with respect to the mounting bases  8  as the first and second bolts  23  and  24  are loosened or tightened. Further, the position of the movable portion  3  can be adjusted at right angles to the linear guides  7 . More specifically, the vertical and transverse inclinations of the supporting members  9  can be independently adjusted by the first, second, and third wedges  15 ,  16  and  17 .  
         [0052]     Each third wedge  17  is located between the vertical surface  8   a  of each mounting base  8  and the vertical surface  9   a  of each movable portion supporting member  9  so as to extend at right angles to the first and second wedges  15  and  16 . Even if the third wedges  17  are moved for adjustment, therefore, the movable portion  3  never moves in the up-down direction. Thus, only the inclination of the movable portion supporting members  9  in the left-right direction b with respect to the mounting bases  8  can be adjusted.  
         [0053]     Then, in clamping the stationary die  4  on the stationary portion  2  and the movable die  5  on the movable portion  3 , the left- and right-hand servomotors  10  are driven simultaneously. Rotary motions of the servomotors  10  are converted into linear motions by the ball screws  13 . With these linear motions, the mounting bases  8  move linearly, guided by the linear guides  7 . Further, the movable portion  3  and the movable portion supporting members  9  on the mounting bases  8  linearly move in a body, guided by the tie bars  6 . Then, the dies  4  and  5  are clamped.  
         [0054]     If a given amount of liquid resin is injected through an injection nozzle of the injection molding machine (not shown) after the stationary die  4  and the movable die  5  are clamped, it is filled into a cavity between the dies  4  and  5 . When filling the liquid resin is completed, an injection press process is started. More specifically, a high-pressure die clamping force is generated so that the liquid resin in the cavity is pressed at high pressure. Thereafter, dwelling and cooling processes are performed, whereupon a molded product is completed.  
         [0055]     If the high-pressure die clamping force is generated by the servomotors  10 , in this case, the movable portion  3  inclines in the up-down direction a and then in the left-right direction b. Thereupon, the outer peripheral edge of the movable portion  3  is deformed toward the stationary portion  2 , and the movable portion  3  is deformed substantially into the shape of a circular arc as viewed laterally or flat.  
         [0056]     As this is done, the inclination of the movable portion  3  in the up-down direction a is absorbed by elastic deformation of the first elastic pressure member  25 . Further, the inclination of the movable portion  3  in the left-right direction b is absorbed by elastic deformation of the second elastic pressure member  31 . Thus, the movable portion supporting members  9  incline in the up-down and left-right directions. Since the supporting members  9  are independent of the mounting bases  8 , however, there is no possibility of any load acting on the mounting bases  8 . Even if the supporting members  9  incline in the up-down and left-right directions, therefore, no load can act on the mounting bases  8  that are supported for linear motion by the linear guides  7 . Thus, the mounting bases  8  can smoothly slide with respect to the guides  7 .  
         [0057]     According to the present embodiment, the movable portion  3  can be easily adjusted in the left-right and up-down directions. Further, the movable portion  3  can be independently adjusted in the up-down and left-right directions. Furthermore, the linear guides  7  and the mounting bases  8  can be protected, so that the life of the device can be lengthened.  
         [0058]     Although the movable portion  3  and the movable portion supporting members  9  are provided independently of one another in the embodiment described above, they may be formed integrally. Further, the respective positions of each third wedge  17  and its corresponding second elastic pressure member  31  may be replaced with each other.  
         [0059]     Furthermore, each second elastic pressure member  31  may be elevated in position so that the upper part of each movable portion supporting member  9  is elastically pressed toward the back of the movable portion  3 . In this case, a vertical moment is generated such as to press the supporting member  9  downward. Thus, the first elastic pressure members  25  that elastically press the supporting members  9  toward the mounting bases  8  may be omitted.  
         [0060]     Although the die clamping unit of the injection molding machine has been described herein, this invention may be also applied to a die-casting machine, press machine, etc.  
         [0061]     This invention is not limited directly to the embodiment described above, and its components may be embodied in modified forms without departing from the scope or spirit of the invention. Further, various inventions may be formed by suitably combining a plurality of components described in connection with the foregoing embodiment. For example, some of the components according to the foregoing embodiment may be omitted. Furthermore, components according to different embodiments may be combined as required.  
         [0062]     Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.