Abstract:
There are provided a rail  10  in which a rolling member rolling surface  11  is formed along the longitudinal direction, a block  20  in which a loaded rolling member rolling surface  27  is formed in an opening  25  comprising a through hole, a plurality of balls  70  disposed and housed between the rolling member rolling surface  11  and the loaded rolling member rolling surface  27  which circulate according to the relative motion of the rail  10  and the block  20 . A sectional shape at right angles to the longitudinal direction of the rail  10  and a sectional shape of the opening  25  are formed into a mutually geometrically similar longitudinal shape. The block  20  is a box type with high rigidity. A contact angle of the ball  70  can be optionally changed by changing the positions alone of the rolling member rolling surface  11  and the loaded rolling member rolling surface  27  to be machined on one type of the block  20  and the rail  10.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The present invention relates to a rolling guide device in which a block and a rail are relatively linearly movably engaged to each other via rows of infinitely circulating rolling members, a manufacturing method thereof, and a driving device including the rolling guide device.  
           [0002]    Heretofore, there has been known a rolling guide device in which a block and a rail are linearly movably engaged to each other via a plurality of rolling members comprising infinitely circulating balls and rollers. To be concrete, as shown in FIG. 8, the rolling guide device comprises a rail  80 , a block  90  having a recess  93  formed on a lower surface thereof in which the rail  80  fits, and a number of rolling members  100  interposed so as to form a row between a rolling member rolling surface  81  of the rail  80  and a loaded rolling member rolling surface  91  of the block  90 .  
           [0003]    Here, the block  90  is provided with rolling member release holes  94  through which the rolling members  100  passed between each pair of the rolling member rolling surface  81  and the loaded rolling member rolling surface  91  are released and returned to an original position again to from an infinite circulation passage of the rolling members  100 .  
           [0004]    Furthermore, when the block  90  is linearly moved relatively along the rail  80 , the rolling members  100  are linearly moved while they rolls between the rolling member rolling surface  81  and the loaded rolling member rolling surface  91 , passed between the rolling member rolling surface  81  and the loaded rolling member rolling surface  91 , returned to the rolling member release hole  94  through a return passage provided in an end plate not shown, and then supplied again between the rolling member rolling surface  81  and the loaded rolling member rolling surface  91 .  
           [0005]    However, for example, in the case that the block  90  is fixed and the rail  80  is moved in the aforesaid rolling guide device, and when a heavy piece is installed at a rail tip portion of the forward side of the rail  80  in FIG. 8 and a moment load is applied thereonto, the load imparts an uneven deformation onto the block  90 , so that a deformation amount (an opening amount of the recess  93 ) is varied on the forward side and the backward side of the block  90  in FIG. 8, which leads to a problem that the position accuracy of the rail  80  is impaired.  
           [0006]    In order to solve this problem, instead of the recess  93 , a through hole may be provided at the center of the block  90  to pass the rail  80  through the inside of the through hole. If constituted in this manner, even in the case that an uneven load is applied onto one side of the rail  80  and the moment load is generated, the recess  93  will not be opened, so that the rail  80  can always securely be held.  
           [0007]    However, even in the rolling guide device constituted in such a manner, machining positions of the opposing rolling member rolling surface  81  and the loaded rolling member rolling surface  91  are required to be changed to various positions (various contact angle positions) in accordance with purposes of use, and hence, the shape of an opening  25  of the block  90  and the external shape of the rail  80  must also be changed in accordance with the above change, thereby causing a complicated problem.  
         SUMMARY OF THE INVENTION  
         [0008]    Therefore, an object of the present invention is to provide a rolling guide device in which even if a large moment is applied to a rail, a block is not deformed, and even if machining positions of a rolling member rolling surface  81  and a loaded rolling member rolling surface  91  are simultaneously changed, the shape itself of the block and the rail is not required to be changed, a manufacturing method thereof, and a driving device including the rolling guide device.  
           [0009]    A first aspect of the present invention is directed to a rolling guide device which comprises a rail in which a rolling member rolling surface is formed along its longitudinal direction, a block in which an opening comprising a through hole is formed, the rail being fitted in this opening, and a rolling member circulation passage including a loaded rolling member rolling surface corresponding to the rolling member rolling surface of the rail is formed, and a plurality of rolling members which are disposed and housed in the rolling member circulation passage and which circulate in accordance with the relative movement of the rail and block, wherein a sectional shape at right angles to the longitudinal direction of the rail and a sectional shape of the opening of the block are formed into a mutually geometrically similar longitudinal shape. In this manner, the opening of the block is made to be a through hole, and therefore, the block is a box type block of high rigidity which will not be deformed, so that it is possible to sufficiently maintain a satisfactory position accuracy of the rail even if a large moment is applied thereonto. In addition, according to the present invention, by appropriately changing the machining positions alone of the rolling member rolling surface and the loaded rolling member rolling surface, it becomes possible to optionally change a contact angle of the rolling members by one type of block and rail. Therefore, even in the case that the purpose of use and the condition of use are different by each user, it is possible to cope with these situations, thereby enabling the manufacture of the rolling guide device easily and at a low price.  
           [0010]    A second aspect of the present invention is directed to the rolling guide device in which the sectional shape at right angles to the longitudinal direction of the rail and the sectional shape of the opening of the block are mutually formed into a curved line with respect to a part in which the rolling member rolling surface and loaded rolling member rolling surface are formed. In this manner, by forming the part of both sectional shapes into a curved line, it is possible to change the contact angle easily by changing the positions of the rolling member rolling surface and the loaded rolling member rolling surface as described above.  
           [0011]    Moreover, a third aspect of the present invention, in the rolling guide device, is to provide a constitution in which the curved line is part of a round shape. If the curved line is a round shape, the relation between the position and the contact angle of the aforesaid rolling member rolling surface and the loaded rolling member rolling surface becomes most important, since the position of each rolling surface can be changed with high accuracy, it is thus possible to change and set the contact angle with high accuracy.  
           [0012]    A fourth aspect of the present invention is directed to the rolling guide device in which the curved line is a part of an ellipse. If the curved line is an ellipse, though the relation of the aforesaid rolling member rolling surface and loaded rolling member rolling surface to the contact angle is not simple as in the case of the aforesaid round shape, it is possible to easily change the contact angle in proportion to the round shape.  
           [0013]    Moreover, a fifth aspect of the present invention is directed to a manufacturing method of a rolling guide device which comprises a process of forming a rolling member rolling surface on a rail along the longitudinal direction, a process of forming a rolling member circulation passage including a loaded rolling member rolling surface corresponding to the rolling member rolling surface of the rail on a block in which an opening comprising a through hole is machined, and a process of inserting the rail into the opening of the block, and disposing and housing, in the rolling member circulation passage, a plurality of rolling members which circulate in accordance with the relative motion of the rail and block, wherein a sectional shape at right angles to the longitudinal direction of the rail and a sectional shape of the opening of the block are machined in advance into a mutually geometrically similar longitudinal shape, and machining positions of both the loaded rolling member rolling surface of the block and the rolling member rolling surface of the rail are appropriately changed, whereby the contact angle of the rolling members to the block and rail is optionally changed.  
           [0014]    Moreover, a sixth aspect of the present invention is directed to a driving device including a rolling guide device which comprises a rail in which a rolling member rolling surface is formed along the longitudinal direction; a block in which an opening comprising a through hole is formed, the rail fits in this opening, and a rolling member circulation passage including a loaded rolling member rolling surface corresponding to the rolling member rolling surface of the rail is formed; and a plurality of rolling members which are disposed and housed in the rolling member circulation passage and which circulate in accordance with the relative motion of the rail and block; wherein a sectional shape at right angles to the longitudinal direction of the rail and a sectional shape of the opening of the block are formed into a mutually geometrically similar longitudinal shape, and there is disposed a linear motor comprising a secondary side arranged on both the main sides of the rail and a primary side arranged in the opening of the block corresponding to this secondary side. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]    [0015]FIG. 1 is a partially cut schematic perspective view of a rolling guide device according to an embodiment of the present invention.  
         [0016]    [0016]FIG. 2 shows a rolling guide device according to an embodiment of the present invention, and FIG. 2 ( a ) is a schematic cross-sectional side view and FIG. 2 ( b ) is a plan view.  
         [0017]    [0017]FIG. 3 is a cross-sectional view of a rolling guide device according to an embodiment of the present invention.  
         [0018]    [0018]FIG. 4 is a cross-sectional view of a rolling guide device in which machining positions alone of a rolling member rolling surface  11  and a loaded rolling member rolling surface  27  are changed.  
         [0019]    [0019]FIG. 5 is a cross-sectional view of the rolling guide device in which machining positions alone of the rolling member rolling surface  11  and the loaded rolling member rolling surface  27  are changed.  
         [0020]    [0020]FIG. 6 is a cross-sectional view showing a driving device according to the present invention.  
         [0021]    [0021]FIG. 7 is a cross-sectional view showing another driving device according to the present invention.  
         [0022]    [0022]FIG. 8 is a cross-sectional view showing a conventional rolling guide device. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0023]    In the following, embodiments of the present invention will be described in detail with reference to the drawings.  
         [0024]    [0024]FIG. 1 to FIG. 3 show a rolling guide device according to an embodiment of the present invention, FIG. 1 is a partially cut schematic perspective view, FIG. 2 ( a ) is a schematic sectional side view, FIG. 2 ( b ) is a plan view, and FIG. 3 is a cross-sectional view. As shown in these drawings, this rolling guide device is constituted of a rail  10 , a block  20 , and a ball (rolling member)  70 .  
         [0025]    A cross section of the rail  10  is a longitudinal shape, and to be concrete, upper and lower surfaces are substantially parallel planes in which both sides are formed into a substantially elliptical shape protruding in an arc-like shape. Moreover, on the top and bottom of the rail  10 , two groove-like rolling member rolling surfaces  11  are formed at right and left, and hence, four groove-like rolling member rolling surfaces  11  are formed in all.  
         [0026]    The block  20  comprises a block body  21  and end plates  23  which are installed on both end faces of the block body  21 . The block body  21  is provided with an opening  25  into which the rail  10  is inserted, and on upper and lower surfaces of this opening  25 , there are formed 4 groove-like loaded rolling member rolling surfaces  27  corresponding to the respective rolling member rolling surfaces  11  of the rail  10 . Between each of the mutually opposing rolling member rolling surfaces  11  and the loaded rolling member rolling surface  27 , a plurality of balls (rolling members)  70  . . . are movably interposed.  
         [0027]    The opening  25  is a through hole and its sectional shape is a longitudinal shape, and detailedly, upper and lower surfaces are substantially parallel planes in which both sides are formed into a substantially elliptical shape protruding like an arc-like shape. That is, a sectional shape at right angles to the longitudinal direction of the rail  10  and a sectional shape of the opening  25  are formed into a mutually geometrically similar longitudinal shape, in the case of this embodiment, an elliptical shape. Therefore, the outer peripheral surface of the rail  10  and the inner peripheral surface of the opening  25  are parallel, and clearance dimensions of both the surfaces are about the same in any part.  
         [0028]    In the block body  21 , two rolling member release holes  51  for releasing the balls in a load area corresponding to the respective loaded rolling member rolling surfaces  27  are formed on top and bottom of the opening  25 , respectively, and hence the four holes  51  are formed in all. On the other hand, on upper and lower surfaces and on both sides of the block  21 , there are provided screw-holes  29  for fixing this block body  21  to other members.  
         [0029]    The end plate  23  is constituted of a rectangular member having about the same shape as the end face of the block body  21 . At the center thereof, there are an opening  53  for passing the rail  10 , and a return passage  55  for forwarding the balls  70  in the load area interposed between the block body  21  and the rail  10  into a rolling member release hole  51  to return the balls to the load area again. In addition, on the outer end face of the end plate  23  is installed a sealing member  57  for preventing dirt from entering the inside and preventing lubricant from leaking from the inside.  
         [0030]    Furthermore, a rolling member circulation passage is defined by the loaded rolling member rolling surface  27  corresponding to the rolling member rolling surface  11  of the rail  10 , the rolling member release hole  51 , and the return passage  55 .  
         [0031]    As a method for machining the loaded rolling member rolling surface  27  in the block  20 , for example, a method can be used in which the opening  25  is perforated in the block  20  by wire cut and the like, and a groove is then formed on the inner surface thereof by grinding only to work the loaded rolling member rolling surface  27 .  
         [0032]    Then, when the rail  10  is moved linearly in its longitudinal direction to the block  20 , the rail  10  smoothly moves as the ball  70  between the rolling member rolling surface  11  of the rail  10  and the loaded rolling member rolling surface  27  of the block  20  moves while rolling.  
         [0033]    In the present invention, since the opening  25  is provided in the block  20  and the rail is passed inside thereof, for example, as shown in FIG. 2 ( a ), the block  20  is fixed to a fixing side member  75 , on the other hand, even if a moving side member  77  is fixed at the tip section of the rail  10  and a moment load is applied to the rail  10 , there does not occur a problem in which the opening  25  is opened and deformed, and the rail  10  always moves smoothly to the same position as in the case where the moving side member  77  is not used, so that it is possible to always maintain satisfactory position accuracy of the moving side member  77 .  
         [0034]    On the other hand, in the present invention, as described above, since the sectional shape at right angles to the longitudinal direction of the rail  10  and the sectional shape of the opening  25  are formed into a mutually geometrically similar ellipse, that is, a longitudinal shape, the clearance dimension of the outer peripheral surface of the rail  10  and the inner peripheral surface of the opening  25  is about the same in any part. Therefore, as shown in FIG. 4 and FIG. 5, even if the same rail and block as the rail  10  and block  20  are used, the machining positions of the rolling member rolling surface  11  and the loaded rolling member rolling surface  27  can be changed to various positions (various positions of a contact angle θ)according to purposes of use. Groove machining of the rolling member rolling surface  11  and the loaded rolling member rolling surface  27  is easy because it can be accomplished by grinding only. That is, according to purposes of use, by changing the machining positions of both the rolling member rolling surface  11  and the loaded rolling member rolling surface  27  appropriately, it is possible to optionally change the contact angle θ (θ 1 , θ 2 ) of the ball  70  to the rail  10  and the block  20 .  
         [0035]    However, in the present embodiment, the sectional shape at right angles to the longitudinal direction of the rail  10  and the sectional shape of the opening  25  of the block  20  are mutually formed into an arc-like shape, that is, a curved line with respect to a part in which the rolling member rolling surface  11  and the loaded rolling member rolling surface  27  are formed.  
         [0036]    In this manner, by forming the part of both sectional shapes into a curved line, it is possible to easily change the contact angle simply by changing the positions of the rolling member rolling surface  11  and the loaded rolling member rolling surface  27  as described above. Incidentally, both or one of the part of rail sectional shape and block sectional shape is a straight line, changing the contact angle is not always easy.  
         [0037]    In the present embodiment, the aforesaid curved line is an arc-like shape, that is, part of a round shape. If the curved line is a round shape, the relation of the position and the contact angle of the aforesaid rolling member rolling surface  11  and loaded rolling member rolling surface  27  becomes most important, since the position of each rolling surface can be changed highly accurately, it is also possible to change and set the contact angle with a high accuracy.  
         [0038]    In addition, the aforesaid curved line may be a part of an elliptical shape. In the case of an ellipse, though the relation of the aforesaid rolling member rolling surface  11  and loaded rolling member rolling surface  27  to the contact angle is not so simple as the case of the aforesaid round shape, it is possible to change the contact angle in proportion to the round shape.  
         [0039]    [0039]FIG. 6 is a transverse sectional view showing a driving device according to the present invention. This driving device is constituted so that magnets (secondary side (secondary conductor))  60 ,  60  are installed so as to be respectively embedded on top and bottom surfaces (principal both surfaces) of the rail  10  of the rolling guide device of the same construction shown in the FIG. 4, and on the other hand, electromagnets (primary side (stator))  61 ,  61  are installed so as to be embedded on top and bottom surfaces of the inner periphery of the opening  25  of the block  20 . A linear motor formed by a pair of the magnet  60  and the magnet  61  of the upper side, and a linear motor formed by a pair of the magnet  60  and the magnet  61  of the lower side are provided at a position vertically symmetrical to the center of the rail  10 . As a linear motor, motors of various construction such as a linear direct current motor and a linear pulse motor can be applied. And, by flowing current to the electromagnets  61 ,  61 , the rail  10  is drive so as to advance and reverse to the block  20 .  
         [0040]    In this embodiment, since the rail  10  is covered by the opening  25  provided in the block  20 , it is possible to provide a position to install the magnet  60  and the electromagnet  16  not only on the upper surface side but also on the lower surface side, that is, on the principal both sides of the rail  10 . Therefore, it is possible to restrain a deformation of a structural member in the radial direction due to magnet attraction, so that thrust is increased by space saving because of two pairs of motors used.  
         [0041]    [0041]FIG. 7 shows an embodiment in which the magnets  60 ,  60  of the inside and outside of the rail  10  shown in FIG. 6 are integrated into one magnet. If the fastening between the rail  10  and the magnet  60  can be securely provided by adhesion or bolting and the like, such means simplifies the construction and reduces the cost.  
         [0042]    Embodiments of the present invention are described in the above, but the present invention is not limited to the aforesaid embodiments, and various modifications are possible within the scope of the claims and the scope of technical idea stated in the specification and drawings. In addition, even in the case of any shape or construction or quality of material or method of use which are not directly stated in the specification and drawings, as long as they demonstrate the action and effect of the present invention, they are within the scope of the technical idea of the present invention.  
         [0043]    For example, in the aforesaid embodiments, the block  20  is used as the fixed side, and the rail  10  is used as the movable side, conversely, the block  20  may be used as the movable side, and the rail  10  may be used as the fixed side.  
         [0044]    Further, in the aforesaid embodiments, the sectional shape at right angles to the longitudinal direction of the rail  10  and the sectional shape of the opening  25  of the block  20  are mutually formed into round shape or a part of an elliptical shape, that is, a curved line, but other curved line may be applicable.  
         [0045]    Furthermore, in the above embodiments, a case is shown in which balls are used as rolling members, but the present invention may be applicable to the case where rollers are used in a similar construction.