Ball screw shaft support structure and actuator

Abstract

To provide a ball screw shaft support structure which prevents deflection of a ball screw shaft to suppress vibration and noise and enable operation at a high speed with a simple and compact structure, and to provide an actuator.SOLUTION: A ball screw shaft support structure includes: a ball screw shaft; a ball screw nut threadedly engaged with the ball screw shaft in a movable manner; and a support member which is installed so as to be movable close to or away from the ball screw shaft, placed in pressure contact with the ball screw shaft by elastic means, and separated from the ball screw shaft against biasing force of the elastic means by the ball screw nut moving close thereto. Ball screw nut side inclined surfaces are provided at both sides along an axial direction of the ball screw shaft on the ball screw nut side, and an inclined surface cushioning material is installed on each ball screw nut side inclined surface.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a ball screw shaft support structure and an actuator, and in particular to a structure that can prevent bending of the ball screw shaft with a simple and compact configuration, and is designed to suppress vibration and noise and accommodate higher speeds. [Background technology]

[0002] For example, Patent Documents 1 and 2 disclose ball screw shaft support structures and actuator configurations. The anti-vibration stabilization device for a long lead screw described in Patent Document 1 supports the long lead screw (ball screw shaft) of an actuator with support rollers to prevent bending of the screw and suppress vibration. The support roller is rotatably attached to a support part, which is normally biased by a spring toward the slider of the actuator. Lower pressure rollers are rotatably attached to both sides of the support part in the width direction. In addition, an inclined surface is provided on both sides of the slider in the moving direction. When the slider approaches the support part, the inclined surface of the slider causes the support part and, ultimately, the support roller to retreat downward against the elastic force of the spring via the lower pressure roller.

[0003] In addition, in the driving member moving mechanism of a machine tool or the like described in Patent Document 2, an anti-shake device is provided beside a ball screw shaft. This anti-shake device is composed of a rotatably installed operating arm and a bearing portion provided at the tip of the operating arm. The operating arm is normally biased toward the ball screw shaft by a coil spring, and the ball screw shaft is supported by the bearing portion. A roller is installed in the bearing portion, and a guide plate is installed on a driving block driven by the ball screw shaft. When the driving block approaches the anti-shake device, the roller abuts against the guide plate, and the bearing portion is moved in a direction away from the ball screw shaft against the elastic force of the coil spring. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Utility Model Application Publication No. 7-3936 [Patent Document 2] Publication number 3-40038 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the above conventional configuration has the following problems. In other words, in the anti-vibration stabilization device for a long lead screw described in Patent Document 1, not only is a support roller rotatably attached to the support part to support the long lead screw, but a lower pressure roller that slides against the inclined surface of the slider is also attached, resulting in the problem that the support part and its surrounding structure are complex. Furthermore, in the drive member moving mechanism of machine tools and the like described in Patent Document 2, the shaft vibration prevention device is installed to the side of the ball screw shaft in a position where it can avoid interference with the moving drive block, which causes the configuration near the drive member moving mechanism to become larger in the horizontal direction, which is a problem.

[0006] The present invention has been made based on these points, and its object is to provide a ball screw shaft support structure and actuator that can prevent bending of the ball screw shaft with a simple and compact configuration, suppress vibration and noise, and accommodate higher speeds. [Means for solving the problem]

[0007] In order to solve the above problem, the ball screw shaft support structure according to claim 1 of the present invention comprises a ball screw shaft, a ball screw nut movably screwed onto the ball screw shaft, and a support member installed so as to be releasable from the ball screw shaft, pressed against the ball screw shaft by elastic means, and moved away from the ball screw shaft against the biasing force of the elastic means as the ball screw nut approaches, characterized in that a ball screw nut side inclined surface is provided on both sides along the axial direction of the ball screw shaft on the ball screw nut side, and an inclined surface cushioning material is installed on the ball screw nut side inclined surface. Furthermore, the ball screw shaft support structure according to claim 2 is the ball screw shaft support structure according to claim 1, characterized in that the support member is composed of a support member main body and a receiving member that receives the ball screw shaft. Furthermore, the ball screw shaft support structure according to claim 3 is the ball screw shaft support structure according to claim 2, characterized in that the support member main body is provided with a support member side roller, and the support member is moved toward and away from the ball screw shaft by rolling the support member side roller along the ball screw nut side inclined surface. Furthermore, the ball screw shaft support structure according to claim 4 is the ball screw shaft support structure according to claim 2 or 3, characterized in that a cushioning material for the receiving member is interposed between the support member main body and the receiving member. Furthermore, the ball screw shaft support structure according to claim 5 is a ball screw shaft support structure according to any one of claims 1 to 4, characterized in that a buffer mechanism is provided to buffer the approaching movement of the support member toward the ball screw shaft. According to a sixth aspect of the present invention, there is provided an actuator including one support member of the ball screw shaft support structure according to any one of the first to fifth aspects. Moreover, an actuator according to a seventh aspect of the present invention is characterized in that a plurality of support members of the ball screw shaft support structure according to any one of the first to fifth aspects of the present invention are provided. Effect of the Invention

[0008] As described above, the ball screw shaft support structure according to claim 1 of the present invention includes a ball screw shaft, a ball screw nut movably screwed to the ball screw shaft, and a support member that is detachably attached to the ball screw shaft, is pressed against the ball screw shaft by elastic means, and is separated from the ball screw shaft against the biasing force of the elastic means when the ball screw nut approaches, and has ball screw nut side inclined surfaces on both sides along the axial direction of the ball screw shaft on the ball screw nut side, and a buffer material is provided on the ball screw nut side inclined surfaces, so that the ball screw shaft can be prevented from bending with a simple and compact structure, vibrations and noise can be suppressed, and the ball screw shaft can be operated at high speed. In particular, the use of the ball screw nut side inclined surfaces can make the attachment and removal operation of the support member smooth. According to the ball screw shaft support structure of claim 2, in the ball screw shaft support structure of claim 1, the support member is composed of a support member main body and a receiving member that receives the ball screw shaft, so that the simple structure prevents bending of the ball screw shaft, suppresses vibration and noise, and enables high-speed operation. According to the ball screw shaft support structure of claim 3, in the ball screw shaft support structure of claim 2, a support member side roller is provided on the support member main body, and the support member is moved toward and away from the ball screw shaft by rolling the support member side roller along the ball screw nut side inclined surface, thereby making it possible to smooth the operation of the support member. Furthermore, according to the ball screw shaft support structure of claim 4, in the ball screw shaft support structure of claim 2 or claim 3, a cushioning material for the receiving member is interposed between the support member main body and the receiving member, so that the impact when the receiving member collides with the ball screw shaft can be mitigated with a simple configuration. According to the ball screw shaft support structure of claim 5, in the ball screw shaft support structure of any one of claims 1 to 4, a buffer mechanism is provided for buffering the approaching movement of the support member to the ball screw shaft, so that the ball screw shaft can be prevented from bending with a simple and compact configuration, vibration and noise can be suppressed, and high-speed operation can be achieved. In particular, the buffer mechanism can suppress abrupt movement of the support member, thereby preventing noise. Furthermore, according to the actuator described in claim 6, one support member of the ball screw shaft support structure described in any one of claims 1 to 5 is installed, so that the simple and compact configuration prevents bending of the ball screw shaft, suppresses vibration and noise, and enables high-speed operation. Furthermore, according to the actuator described in claim 7, a plurality of support members of the ball screw shaft support structure described in any one of claims 1 to 5 are installed, so that even if the ball screw shaft is long, the simple and compact configuration prevents the ball screw shaft from bending, suppresses vibration and noise, and enables high-speed operation. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing a first embodiment of the present invention, and is a perspective view of an actuator. [Diagram 2]FIG. 1 is a diagram showing a first embodiment of the present invention, and is a partial vertical cross-sectional view of an actuator, with an enlarged view of the vicinity of a support member. [Diagram 3] FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2, showing the first embodiment of the present invention. [Figure 4] FIG. 1 is a diagram showing the first embodiment of the present invention, and is a partial perspective view showing an enlarged view of the vicinity of a support member of an actuator. [Diagram 5] FIG. 1 is a diagram showing a first embodiment of the present invention, and is a perspective view of a ball screw shaft support structure. [Figure 6] FIG. 1 is a diagram showing a first embodiment of the present invention, a partial vertical cross-sectional view of an actuator, and an enlarged view of the vicinity of a support member when a slider approaches the support member. [Figure 7] FIG. 1 is a diagram showing a first embodiment of the present invention, a partial perspective view with a part of an actuator removed, and an enlarged view of the vicinity of a support member when a slider approaches the support member. [Figure 8] FIG. 1 shows a first embodiment of the present invention, a partial longitudinal cross-sectional view of the actuator, and an enlarged view of the vicinity of the support member when the roller on the ball screw nut side rides up onto the inclined surface on the support member side and the support member begins to move away from the ball screw shaft. [Figure 9] FIG. 1 is a diagram showing a first embodiment of the present invention, a partial longitudinal cross-sectional view of an actuator, and an enlarged view of the vicinity of the support member in a state where the support member is separated from the ball screw shaft and the receiving member and the lower surface side sliding member provided on the lower surface side of the slider are in sliding contact with each other. [Figure 10] FIG. 1 is a diagram showing a first embodiment of the present invention, a partial vertical cross-sectional view of an actuator, and an enlarged view of the vicinity of a support member in a state immediately after a slider has passed the support member. [Figure 11] 11A is a partial perspective view showing a state in which a part of an actuator is removed, and FIG. 11B is a cross-sectional view taken along line XIb-XIb of FIG. 11A, illustrating a second embodiment of the present invention. [Figure 12]12(a) is a partial perspective view showing a state in which a part of an actuator has been removed, and FIG. 12(b) is a cross-sectional view taken along line XIIb-XIIb of FIG. 12(a), showing a third embodiment of the present invention. [Figure 13] 13(a) is a perspective view of a ball screw shaft support structure, FIG. 13(b) is a view of the ball screw shaft support structure with a portion thereof removed, and FIG. 13(c) is a cross-sectional view taken along XIIIc-XIIIc in FIG. 13(a), showing a fourth embodiment of the present invention. [Figure 14] 14A and 14B are diagrams showing a fifth embodiment of the present invention, in which FIG. 14A is a perspective view of a ball screw shaft support structure, and FIG. 14B is a cross-sectional view taken along line XIVb-XIVb of FIG. 14A. [Figure 15] 15A and 15B are diagrams showing a sixth embodiment of the present invention, in which FIG. 15A is a perspective view of a ball screw shaft support structure, and FIG. 15B is a sectional view taken along line XVb-XVb of FIG. 15A. [Figure 16] FIG. 13 is a perspective view of an actuator according to a seventh embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] A first embodiment of the present invention will be described below with reference to Figs. 1 to 10. Fig. 1 is a perspective view showing the overall configuration of an actuator 1 according to this first embodiment, Fig. 2 is a longitudinal sectional view of a main portion, and Fig. 3 is a sectional view taken along line III-III of Fig. 2. As shown in Figs. 1 to 3, there is a base 3 having a substantially U-shaped cross section. Guide rails 5, 5 are provided on both the left and right inner side surfaces of the base 3. Guide grooves 7, 7 are formed in the guide rails 5, 5, respectively.

[0011] A ball screw shaft 9 is mounted inside the base 3. As shown in Fig. 1, the base 3 has a bearing 8a at its front end (lower left in Fig. 1) and a bearing 8b at its rear end (upper right in Fig. 2). The ball screw shaft 9 is supported by the bearings 8a and 8b. The ball screw shaft 9 has a spiral groove 9a formed therein.

[0012] As shown in Figs. 1 and 2, the slider 11 is installed on the base 3 so as to be movable in the left-right direction. End caps 13, 13 are installed on one side (upper left side in Fig. 1) of the slider 11 in the width direction at both ends in the front-rear direction (direction from lower left to upper right in Fig. 1). End caps 15, 15 are installed on the other side (lower right side in Fig. 1) of the slider 11 in the width direction at both ends in the front-rear direction (direction from lower left to upper right in Fig. 1) (the end cap on the rear end side is not shown). A return path (not shown) is formed in the end caps 13, 15. Unloaded circulation paths (not shown) are formed on both sides in the width direction (direction from upper left to lower right in Fig. 1) of the slider 11. Guide grooves (not shown) are formed on both side surfaces in the width direction (direction from upper left to lower right in Fig. 1) of the slider 11.

[0013] Steel balls (not shown) roll and circulate in one unloaded circulation path (not shown) in the slider 11, the return path of the one end cap 13, the return path of the other end cap 13, and the space between the guide groove 7 of the one guide rail 5 and one guide groove (not shown) of the slider 11. Steel balls (not shown) roll and circulate in the other unloaded circulation path (not shown) in the slider 11, the return path of the one end cap 15, the return path of the other end cap 15, and the space between the guide groove 7 of the other guide rail 5 and the other guide groove (not shown) of the slider 11. With this configuration, the slider 11 is movable relative to the base 3.

[0014] As shown in Fig. 2, the slider 11 has a ball screw nut accommodating member 27, and a ball screw nut 31 is fixed in the ball screw nut accommodating member 27. The ball screw nut 31 has a ball screw nut body 33, an end cap 35 on the front end side (left side in Fig. 2), and an end cap 37 on the rear end side (right side in Fig. 2). The ball screw shaft 9 penetrates the ball screw nut 31. A spiral groove 39 is formed on the inner peripheral surface of the ball screw nut body 33. An unloaded circulation path (not shown) is formed in the ball screw nut body 33, and a return path (not shown) is formed in the end caps 35 and 37.

[0015] Steel balls 41 roll and circulate in an unloaded circulation path (not shown) of the ball screw nut body 33, in return paths (not shown) of the end caps 35, 37, and in a space between a spiral groove 39 of the ball screw nut body 33 and a spiral groove 9a of the ball screw shaft 9. As shown in FIG. 1, a motor 43 is installed on the rear end side (upper right side in FIG. 1) of the base 3. The ball screw shaft 9 is rotated and driven by this motor 43. When the ball screw shaft 9 is rotated and driven, the slider 11 is moved in the front-rear direction (left-right direction in FIG. 2).

[0016] 2, resin-made front rollers 21, 21 are rotatably installed as ball screw nut side rollers on both sides in the width direction (both sides in the paper surface direction in FIG. 2) of the lower front end side (left side in FIG. 2) of the slider 11 (the front roller 21 on the front side in FIG. 2 is not shown). Resin-made rear rollers 23, 23 are rotatably installed as ball screw nut side rollers on both sides in the width direction (both sides in the paper surface direction in FIG. 2) of the lower rear end side (right side in FIG. 2) of the slider 11 (the rear roller 23 on the front side in FIG. 2 is not shown). Plate-shaped lower surface side sliding members 25, 25 are installed on both ends in the width direction (both sides in the paper surface direction in FIG. 2) of the lower side of the slider 11 (the lower surface side sliding member 25 on the front side in FIG. 2 is not shown).

[0017] 2 and 4, the base 3 is formed with a support member accommodating recess 51. The ball screw shaft support structure 47 is installed in the support member accommodating recess 51. The ball screw shaft support structure 47 includes a support member support member 50. The support member support member 50 includes a support member base 53. Support member base mounting plates 54, 54 are fixed to both front and rear ends of the support member base 53. Through holes 52, 52 are formed at both ends of the support member base mounting plate 54. The support member base mounting plates 54, 54 are fixed to the support member base 53 by fixing screws 58. The support member support member 50 includes support member guide pillars 55, 55. The support member guide pillars 55, 55 are erected at both ends of the support member base 53 in the front-rear direction (left-right direction in FIG. 2). The guide posts 55, 55 are fixed to the support member base 53 by fixing screws 56, 56. As shown in FIG. 2, a support member base accommodating hole 49 is formed in the bottom of the support member accommodating recess 51, and the support member base 53 is installed in the support member base accommodating hole 49. The support member base 53, and therefore the support member support member 50, are fixed to the base 3 by passing a fixing screw 59 through the through hole 52 of the support member base mounting plate 54 and screwing it into the base 3. Further, the support member supporting member 50 has a coil spring 65 as an elastic means. The coil spring 65 is stretched between a support member 61 (to be described later) and the support member base 53. Further, a U-shaped leaf spring 57 which is part of a shock-absorbing mechanism to be described later is provided at the center of the support member base 53 in the front-rear direction (left-right direction in FIG. 2).

[0018] The ball screw shaft support structure 47 includes a support member 61. The support member 61 is installed in the support member accommodating recess 51 and above the support member base 53. As shown in FIG. 5, the support member 61 includes a support member body 62, and guide through holes 63, 63 are formed on both ends of the support member body 62 in the front-rear direction (the direction from the lower left to the upper right in FIG. 5). Slide bearings 64, 64 are press-fitted into the guide through holes 63, 63, and the support member guide pillars 55, 55 are arranged to penetrate these slide bearings 64, 64 and are in sliding contact with the slide bearings 64, 64. The support member 61 is movable in the up-down direction along the support member guide pillars 55, 55. In addition, as shown in FIG. 2, a coil spring 65 is stretched between the support member 61 and the support member base 53 as the elastic means. The support member 61 is constantly pressed and urged toward the ball screw shaft 9 side (upper side in FIG. 2) by the coil spring 65 . As described above, the support member support member 50 is composed of the support member base 53, the support member base mounting plates 54, 54 fixed to the support member base 53, the support member guide pillars 55, 55, and the coil spring 65 elastically supporting the support member main body 62.

[0019] On both sides of the front (lower left in FIG. 5) of the upper surface of the support member main body 62 in the width direction (direction from upper left to lower right in FIG. 5), front side inclined surfaces 71, 71 are formed as support member side inclined surfaces, and on both sides of the rear (upper right in FIG. 5) of the upper surface of the support member main body 62 in the width direction (direction from upper left to lower right in FIG. 5), rear side inclined surfaces 73, 73 are formed as support member side inclined surfaces. The support member 61 has, for example, front side cushioning materials 75, 75 and rear side cushioning materials 77, 77 made of low-resilience rubber as cushioning materials for the support member side inclined surfaces. The front side cushioning materials 75, 75 are installed on the front side inclined surfaces 71, 71, and the rear side cushioning materials 77, 77 are installed on the rear side inclined surfaces 73, 73.

[0020] 2, when the slider 11 moves toward the support member 61 and the front rollers 21 roll on the rear cushioning materials 77 of the rear inclined surfaces 73, the support member 61 is pressed and urged downward in Fig. 6 against the elastic force of the coil spring 65. Also, when the slider 11 moves toward the support member 61 from the side opposite to the direction shown in Fig. 2 and the rear rollers 23 roll on the front cushioning materials 75 of the front inclined surfaces 71, the support member 61 is pressed and urged downward in Fig. 6 against the elastic force of the coil spring 65.

[0021] Further, the support member 61 has a support portion 81. A support portion recess 79 is formed in the center of the upper surface side of the support member main body 62, and the support portion 81 is installed in this support portion recess 79. The support portion 81 has a receiving member 83 made of, for example, POM (polyoxymethylene) and a receiving member cushioning material 87 made of, for example, felt. The receiving member 83 is disposed on the upper surface side and is adapted to receive the ball screw shaft 9. The receiving member 83 is detachably installed in the support portion recess 79 via the receiving member cushioning material 87. The receiving member 83 has through holes 88, 88 with countersunk holes, and the receiving member 83 is fixed to the support member main body 62 by passing bolts 89, 89 through the through holes 88, 88 and screwing them into the female threaded portions 67, 67 formed in the support portion recess 79. The receiving member cushioning material 87 is fastened and fixed together with the receiving member 83 by the bolts 89, 89. In addition, set screws 84, 84 are screwed into the female threaded portions 67, 67 formed in the support portion recess 79 from the lower surface side of the support member main body 62, and by adjusting the screwing positions of the set screws 84, 84, the receiving member cushioning material 87 is prevented from being crushed more than necessary and the height of the receiving member 83 is adjusted. A recess 85 for receiving the ball screw shaft 9 is formed on the upper surface side of the receiving member 83. Both widthwise sides (in FIG. 5) of the recess 85 of the receiving member 83 are planar sliding portions 86, 86. As shown in FIG. 2, when the support member 61 is pressed and urged upward in FIG. 2 by the elastic force of the coil spring 65, the recess 85 of the receiving member 83 of the support portion 81 supports the vicinity of the center of the ball screw shaft 9, preventing the ball screw shaft 9 from bending. In addition, a front side inclined surface 82a that is approximately continuous with the front side inclined surfaces 71, 71 of the support member main body 62 is formed in front of the receiving member 83, and a rear side inclined surface 82b that is approximately continuous with the rear side inclined surfaces 73, 73 of the support member main body 62 is formed in rear of the receiving member 83.

[0022] The felt cushioning material 87 for receiving member is intended to reduce the impact when the receiving member 83 collides with the ball screw shaft 9, and also, for example, cushioning materials 91, 91 for supporting member made of low-resilience rubber are provided on the lower surface side of the support member main body 62. These cushioning materials 91, 91 for supporting member reduce the impact when the support member 61 collides with the support member base 53. As described above, the support member 61 is composed of the support member main body 62, the support portion 81 installed on the support member main body 62, and the front side cushioning materials 75, 75 and rear side cushioning materials 77, 77 installed on the front side inclined surfaces 71, 71 and rear side inclined surfaces 73, 73 of the support member main body 62.

[0023] As shown in FIG. 2, a U-shaped leaf spring 57, which is a part of a cushioning mechanism described later, is installed in the center of the support member base 53 in the front-rear direction (left-right direction in FIG. 2), and is fixed to the support member base 53 by fixing screws 96. As shown in FIG. 3 and FIG. 5, abutment members 93, which are a part of a cushioning mechanism described later, are fixed to both sides of the support member 61 in the width direction (left-right direction in FIG. 3). The support member 61 is inserted between both ends of the leaf spring 57 via the abutment members 93. The leaf spring 57 and the abutment members 93 form a cushioning mechanism 95. The cushioning mechanism 95 cushions the upward movement of the support member 61, i.e., the movement of the support member 61 toward the ball screw shaft 9.

[0024] Next, the operation of the first embodiment will be described. When the ball screw shaft 9 is rotated and driven by the motor 43, the slider 11 advances and retreats in the front-rear direction. When the slider 11 is separated from the support member 61, as shown in Fig. 2, the support member 61 is pressed and urged upward in Fig. 2 by the elastic force of the coil spring 65, and the vicinity of the center of the ball screw shaft 9 is supported by the recess 85 of the receiving member 83 of the support part 81, preventing the ball screw shaft 9 from bending.

[0025] As shown in Figs. 6 and 7, when the slider 11 approaches the support member 61 from the right side in Fig. 6, the front rollers 21, 21 come into contact with the rear cushioning materials 77, 77 of the rear inclined surfaces 73, 73 and start rolling. As a result, the support member 61 is pressed and urged toward the anti-ball screw shaft 9 side (lower side in Fig. 6) against the elastic force of the coil spring 65, and the support of the ball screw shaft 9 by the recess 85 of the receiving member 83 is released. The impact when the front rollers 21, 21 collide with the rear cushioning materials 77, 77 is mitigated by the rear cushioning materials 77, 77. Fig. 8 shows a state in which the slider 11 approaches further toward the support member 61, and the support member 61 is further pressed and urged toward the anti-ball screw shaft 9 side (lower side in Fig. 8). When the slider 11 moves further to the left in Figure 8, the front rollers 21, 21 abut against the rear inclined surfaces 82b, 82b of the receiving member 83 and roll, then abut against the sliding portions 86, 86 of the receiving member 83 and roll, and further abut against the front inclined surfaces 82a, 82a of the receiving member 83 and roll.

[0026] 9, when the slider 11 moves directly above the support member 61, the front rollers 21, 21 move away from the receiving member 83, but the sliding parts 86, 86 of the receiving member 83 of the support member 61 come into sliding contact with the lower surface side sliding members 25, 25 of the slider 11. At this time, the support member 61 is pressed and urged most downward. The impact when the support member 61 collides with the support member base 53 is mitigated by the support member cushioning materials 91, 91.

[0027] Next, as the slider 11 passes above the support member 61, the rear rollers 23, 23 of the slider 11 roll against the rear inclined surfaces 82b, 82b, sliding portions 86, 86, and front inclined surfaces 82a, 82a of the receiving member 83, and then press and urge the support member 61 toward the anti-ball screw shaft 9 side (lower side in Figure 10) against the elastic force of the coil spring 65 via the front cushioning materials 75, 75 of the front inclined surfaces 71, 71, but as the slider 11 moves, this pressing and urging is gradually released. 10, when the slider 11 is moved to the left in Fig. 10, the support member 61 is again pressed and urged upward in Fig. 10 by the elastic force of the coil spring 65, and the vicinity of the center of the ball screw shaft 9 is supported by the recess 85 of the receiving member 83 of the support part 81, thereby preventing the ball screw shaft 9 from bending. The impact generated when the receiving member 83 comes into contact with the ball screw shaft 9 again is buffered by the receiving member buffer 87. In addition, the sudden rise of the support member 61 when it returns to the upper side is mitigated by the leaf spring 57 of the buffer mechanism 95 coming into contact with the abutment member 93 and providing resistance, thereby preventing the generation of noise.

[0028] The same applies when the slider 11 approaches and passes over the support member 61 from the opposite side to the direction shown in Fig. 2. In this case, the rear rollers 23, 23 of the slider 11 come into contact with the front cushioning materials 75, 75 of the front inclined surfaces 71, 71 of the support member 61 and roll, so that the support member 61 is pressed down against the biasing force of the coil spring 65. Moreover, the ball screw shaft support structure 47 is structured so as to be detachable from the support member accommodating recess 51 as a single unit.

[0029] Next, the effects of the first embodiment will be described. First, the simple and compact configuration can prevent bending of the ball screw shaft 9, suppressing vibration and noise and enabling higher speeds to be accommodated. That is, the support member 61 having the receiving member 83 that supports the ball screw shaft 9 is constantly biased toward the ball screw shaft 9 by the coil spring 65, and is appropriately pressed down by the cooperation of the front rollers 21, 21 and rear rollers 23, 23 of the slider 11 and the front inclined surfaces 71, 71 and rear inclined surfaces 73, 73 of the support member 61. In addition, since a cushioning material 87 for the receiving member is interposed between the receiving member 83 and the support member main body 62, the impact when the receiving member 83 collides with the ball screw shaft 9 can be mitigated with a simple structure. Moreover, since the receiving member 83 is detachably installed, it can be easily replaced. Moreover, since the cushioning material 87 for the receiving member is made of felt, the structure is simple and the cushioning effect and sound absorbing effect are high. Furthermore, since cushioning materials 91, 91 for the support member are also provided on the lower surface side of the support member 61, it is possible to mitigate the impact when the support member 61 collides with the support member base 53. In addition, since the support member 61 is raised and lowered by cooperation between the front roller 21, the rear roller 23, the front inclined surfaces 71, 71, and the rear inclined surfaces 73, 73, the raising and lowering movement of the support member 61 can be made smooth. In addition, front side cushioning materials 75, 75 and rear side cushioning materials 77, 77 are provided on the front side inclined surfaces 71, 71 and rear side inclined surfaces 73, 73, so that the impact when the front roller 21 or the rear roller 23 collides can be mitigated. The support member cushioning materials 91, 91, the front side cushioning materials 75, 75 and the rear side cushioning materials 77, 77 are made of, for example, low-resilience rubber, and therefore a high cushioning effect can be obtained with a simple structure. In addition, since a buffer mechanism 95 is provided, a sudden rise of the support member 61 is suppressed, and the impact on the ball screw shaft 9 is mitigated and noise is prevented. In addition, since the buffer mechanism 95 is composed of the leaf spring 57 and the abutment members 93, 93, the configuration is also simple. Furthermore, since the actuator 1 is provided with one support member 61, the structure is simple.

[0030] Next, a second embodiment of the present invention will be described with reference to FIG. As shown in FIG. 11, an actuator 101 according to the second embodiment is provided with a ball screw shaft support structure 47 similar to that of the first embodiment described above, but front inclined surface members 103, 103 are provided on the underside of the slider 11 instead of the front rollers 21, 21, and rear inclined surface members 105, 105 are provided instead of the rear rollers 23, 23.

[0031] 11(b), the front side inclined surface member 103 is a member provided with a ball screw nut side inclined surface 107 parallel to the rear side inclined surface 73 of the support member main body 62. The rear side inclined surface member 105 is a member provided with a ball screw nut side inclined surface 109 parallel to the front side inclined surface 71 of the support member main body 62.

[0032] In the case of this second embodiment, the ball screw nut side inclined surface 107 of the front side inclined surface member 103 abuts against the rear side inclined surface 73 of the support member main body 62, or the ball screw nut side inclined surface 109 of the rear side inclined surface member 105 abuts against the front side inclined surface 71 of the support member main body 62, thereby pushing the support member 61 downward. As shown in FIG. 5, a front cushioning material 75 and a rear cushioning material 77 are provided on the front inclined surface 71 and the rear inclined surface 73 of the support member main body 62, but cushioning materials (not shown) may also be provided on the inclined surface 107 and the inclined surface 109. Further, it is also possible to consider a case where no cushioning material is provided on the front inclined surface 71 and the rear inclined surface 73 of the support member main body 62, and a cushioning material (not shown) is provided on the inclined surface 107 and the inclined surface 109. The same components as those in the first embodiment are denoted by the same reference numerals and the description thereof will be omitted.

[0033] Next, a third embodiment of the present invention will be described with reference to FIG. As shown in Figure 12, the actuator 201 has front side inclined surface members 103, 103 and rear side inclined surface members 105, 105 installed on the underside of the slider 11, as in the case of the second embodiment described above, but a ball screw shaft support structure 203 is installed within the support member accommodating recess 51 of the base 3.

[0034] The ball screw shaft support structure 203 includes a support member 204 and a support member support member 50. The support member 204 includes a support member body 205. Guide through holes 207, 207 are formed at both ends in the front-rear direction (the direction from the lower left to the upper right in FIG. 12(a)) of the support member body 205. Slide bearings 209, 209 are press-fitted into the guide through holes 207, 207, and the support member guide pillars 55, 55 are arranged to pass through these slide bearings 209, 209, and are in sliding contact with the slide bearings 209, 209.

[0035] Support member side rollers 211, 211 are rotatably installed on both ends in the width direction (the direction from the upper left to the lower right in FIG. 12(a)) of the support member main body 205. In the case of the third embodiment, the support member side rollers 211, 211 abut against the inclined surface 107 of the front side inclined surface member 103 and the inclined surface 109 of the rear side inclined surface member 105 installed on the slider 11 and roll, so that the support member 204 is pressed downward and urged. Further, a buffer material (not shown) may be provided on the inclined surface 107 and the inclined surface 109. The same components as those in the first embodiment are denoted by the same reference numerals and the description thereof will be omitted.

[0036] Next, a fourth embodiment of the present invention will be described with reference to FIG. In the fourth embodiment, a ball screw shaft support structure 301 as shown in Fig. 13 is used. This ball screw shaft support structure 301 has a configuration substantially similar to the ball screw shaft support structure 47 in the first and second embodiments described above, but a buffer mechanism 303 is provided instead of the buffer mechanism 95.

[0037] The cushioning mechanism 303 is composed of a contact member 305 having an approximately U-shaped cross-sectional shape fixed to the support member base 53, and leaf springs 307, 307 installed on both sides of the width direction (left and right direction in Figure 13 (c)) of the support member main body 62. For example, as shown in FIG. 13(a), the support member 61 is disposed inside the abutment member 305, and the tip sides of the leaf springs 307, 307 abut against the inner side surface of the abutment member 305 to bias it, as shown in FIG. 13(b) and FIG. 13(c).

[0038] According to the buffer mechanism 303, like the buffer mechanism 95 in the first embodiment described above, the upward movement of the support member 61, that is, the movement toward the ball screw shaft 9, is buffered.

[0039] Next, a fifth embodiment of the present invention will be described with reference to FIG. In the fifth embodiment, a ball screw shaft support structure 401 as shown in Fig. 14 is used. This ball screw shaft support structure 401 has a configuration substantially similar to the ball screw shaft support structure 47 in the first and second embodiments described above, but buffer mechanisms 403, 403 are provided on both sides in the width direction of the support member main body 62 (the left-right direction in Fig. 14(b)).

[0040] The buffer mechanism 403 has a damper mounting member 405. As shown in Fig. 14(a), stepped through holes 407, 407 are provided in the center of the damper mounting member 405. The damper mounting member 405 is fixed to the support member main body 62 by passing fixing screws 409, 409 through the stepped through holes 407, 407 and screwing them into the support member main body 62. As shown in Fig. 14(a), dampers 411, 411 are provided at both ends of the damper mounting member 405 in the front-rear direction. The damper 411 has a cylinder 413 and a rod 415. Oil (not shown) is sealed in the cylinder 413, and a piston (not shown) is fixed to the end of the rod 415 on the inside side of the cylinder 413. The lower end of the rod 415 in Fig. 14 is fixed to the base of an actuator (not shown). Therefore, when the support member 61 is moved in the vertical direction in Fig. 14, the cylinder 413 is moved relative to the rod 415. At this time, the movement of the cylinder 413 and, by extension, the support member 61 is buffered by the resistance of the oil (not shown) in the cylinder 413.

[0041] Next, a sixth embodiment of the present invention will be described with reference to FIG. In the sixth embodiment, a ball screw shaft support structure 501 as shown in Fig. 15 is used. This ball screw shaft support structure 501 has a configuration substantially similar to the ball screw shaft support structure 47 in the first and second embodiments described above, but a buffer mechanism 503 is provided on a support member base 53. The buffer mechanism 503 has a rectangular plate 505 fixed to the support member base 53. Dampers 507, 507, 507, 507 (the damper 507 at the left end in FIG. 15(a) is not shown) are provided at each corner of this plate 505. The damper 507 has a similar configuration to the damper 411 in the fifth embodiment described above, and has a cylinder 509 and a rod 511. The cylinder 509 is fixed to the plate 505, and the upper end of the rod 511 in FIG. 15 is fixed to the bottom surface of the support member main body 62. The damper 507 damps the movement of the support member 61 in the vertical direction in FIG.

[0042] Next, a seventh embodiment of the present invention will be described with reference to FIG. In the first embodiment described above, a configuration was given in which one ball screw shaft support structure 47 was provided at one central location in the axial direction, but in the actuator 701 according to the seventh embodiment, ball screw shaft support structures 47, 47 are provided at two locations in the axial direction. Other configurations are the same as those in the first embodiment, and the same parts in the drawings are given the same reference numerals and their explanation is omitted.

[0043] The seventh embodiment also provides the same actions and effects as the first embodiment, but in the seventh embodiment, even if the ball screw shaft 9 is longer than in the first embodiment, deflection of the ball screw shaft 9 is prevented, vibration and noise are suppressed, and the ball screw shaft 9 can be operated at high speed.

[0044] The present invention is not limited to the first to seventh embodiments. First, in the first to seventh embodiments, the case where one or two support members are provided has been described, but the present invention is not limited to this, and three or more support members may be provided. In addition, the material of the receiving member may be various other materials with good sliding properties, such as oil-impregnated sintered materials, in addition to POM. The material of the cushioning material may be various, such as felt or low-resilience rubber, other cloth, rubber, resin, gel material, sponge or other porous material. The roller may be made of various materials such as rubber, oil-impregnated sintered material, etc., in addition to resin. Also, the support member base can be integrated with the actuator base, and the support member guide posts can be fixed directly to the base. Additionally, the configurations shown in the drawings are merely examples. [Industrial Applicability]

[0045] The present invention relates to a ball screw shaft support structure and an actuator, and in particular to a ball screw shaft support structure and actuator that have a simple and compact configuration to prevent bending of the ball screw shaft, suppress vibration and noise, and enable high-speed operation, and is suitable for industrial robots, for example. [Explanation of symbols]

[0046] 1 Actuator 9 Ball screw shaft 11 Slider 21 Front roller 23 Rear roller 31 Ball screw nut 57 Leaf spring (part of the shock absorber mechanism) 61 Support material 65 Coil spring (elastic means) 71 Front slope 73 Rear slope 81 Support Department 83 Supporting member 87 Cushioning material for receiving parts 95 Buffer mechanism 101 Actuator 201 Actuator 303 Buffer mechanism 403 Buffer mechanism 503 Buffer mechanism 701 Actuator

Claims

1. A ball screw shaft; a ball screw nut movably screwed to the ball screw shaft; a support member that is detachably disposed on the ball screw shaft, that is pressed against the ball screw shaft by an elastic means, and that is moved away from the ball screw shaft against the biasing force of the elastic means when the ball screw nut approaches; Equipped with a ball screw nut side inclined surface is provided on both sides along the axial direction of the ball screw shaft on the ball screw nut side, A ball screw shaft support structure characterized in that a cushioning material for an inclined surface is installed on the inclined surface on the ball screw nut side.

2. 2. The ball screw shaft support structure according to claim 1, The support member is composed of a support member body and a receiving member for receiving the ball screw shaft. A ball screw shaft support structure comprising:

3. 3. The ball screw shaft support structure according to claim 2, The support member body is provided with a support member side roller, a support member side roller that rolls along the inclined surface on the ball screw nut side, thereby causing the support member to come into contact with and be separated from the ball screw shaft.

4. In the ball screw shaft support structure according to claim 2 or 3, A ball screw shaft support structure, characterized in that a cushioning material for the receiving member is interposed between the support member body and the receiving member.

5. In the ball screw shaft support structure according to any one of claims 1 to 4, a shock absorbing mechanism for absorbing the approaching movement of the support member to the ball screw shaft,

6. An actuator comprising one support member of the ball screw shaft support structure according to any one of claims 1 to 5.

7. An actuator comprising a plurality of support members of the ball screw shaft support structure according to any one of claims 1 to 5.

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