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 particularly relates to an invention devised to prevent the deflection of a ball screw shaft with a simple and compact configuration, suppress vibration and noise, and cope with high speed operation.

Background Art

[0002] As those disclosing the configurations of a ball screw shaft support structure and an actuator, for example, there are Patent Document 1 and Patent Document 2. The anti-vibration and stabilization device for a long lead screw described in Patent Document 1 prevents the deflection of the long lead screw (ball screw shaft) of the actuator by supporting it with support rollers and suppresses vibration. The support rollers are rotatably attached to support components, and the support components are constantly biased toward the slider side of the actuator by springs. Lower pressure rollers are rotatably attached to both sides in the width direction of the support components. Inclined surfaces are provided on both sides in the traveling direction of the slider. When the slider approaches the support components, the inclined surfaces of the slider cause the support components, and thus the support rollers, to be retracted downward against the elastic force of the springs via the lower pressure rollers.

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

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, the above conventional configuration has the following problems. That is, in the anti-vibration stabilization device of the long lead screw described in Patent Document 1, not only is a support roller rotatably attached to support the long lead screw to the support parts, but also a downward pressure roller that slidably contacts the inclined surface of the slider is attached. There was a problem that the support parts and the surrounding configuration were complicated. In addition, in the driving member movement mechanism of a machine tool or the like described in Patent Document 2, since the shaft runout prevention device is installed at a position beside the ball screw shaft where buffering with the moving drive block can be avoided, there is a problem that the configuration in the vicinity of the driving member movement mechanism becomes large-sized in the lateral direction.

[0006] The present invention has been made based on such points, and its object is to provide a ball screw shaft support structure and an actuator that can prevent the deflection of the ball screw shaft with a simple and compact configuration, suppress vibration and noise, and cope with high speed.

Means for Solving the Problems

[0007] The ball screw shaft support structure according to claim 1 of the present invention for solving the above problems includes a ball screw shaft, a ball screw nut movably screwed onto the ball screw shaft, and a support member that is detachably installed on the ball screw shaft and 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 by the approach of the ball screw nut. Ball screw nut side inclined surfaces are provided on both sides along the axial direction of the ball screw shaft on the ball screw nut side, and a buffer material for the inclined surface is installed on the ball screw nut side inclined surface. Further, the ball screw shaft support structure according to claim 2 is characterized in that, in the ball screw shaft support structure according to claim 1, the support member is composed of a support member main body and a receiving member for receiving the ball screw shaft. Further, the ball screw shaft support structure according to claim 3 is characterized in that, in the ball screw shaft support structure according to claim 2, a support member side roller is provided on the support member main body, and the support member is separated from the ball screw shaft by rolling the support member side roller along the ball screw nut side inclined surface. Further, the ball screw shaft support structure according to claim 4 is characterized in that, in the ball screw shaft support structure according to claim 2 or claim 3, a buffer material for the receiving member is inserted between the support member main body and the receiving member. Further, the ball screw shaft support structure according to claim 5 is characterized in that, in the ball screw shaft support structure according to any one of claims 1 to 4, a buffer mechanism for buffering the approaching movement of the support member with respect to the ball screw shaft is provided. Further, the actuator according to claim 6 is characterized in that one support member of the ball screw shaft support structure according to any one of claims 1 to 5 is installed. Further, the actuator according to claim 7 is characterized in that a plurality of support members of the ball screw shaft support structure according to any one of claims 1 to 5 are installed.

Advantages of the Invention

[0008] As described above, according to the ball screw shaft support structure described in claim 1 of the present invention, a ball screw shaft, a ball screw nut movably screwed onto the ball screw shaft, and an elastic means detachably installed on the ball screw shaft and pressed against the ball screw shaft by the elastic means and separated from the ball screw shaft against the biasing force of the elastic means by the approach of the ball screw nut, and ball screw nut side inclined surfaces are provided on both sides along the axial direction of the ball screw shaft on the ball screw nut side, and a buffer material for the inclined surface is installed on the ball screw nut side inclined surface. Therefore, it is possible to prevent the deflection of the ball screw shaft, suppress vibration and noise, and operate at high speed with a simple and compact configuration. In particular, by using the ball screw nut side inclined surface, the separation and contact operation of the support member can be made smooth. Further, according to the ball screw shaft support structure described in claim 2, in the ball screw shaft support structure described in claim 1, since the support member is composed of a support member main body and a receiving member for receiving the ball screw shaft, it is possible to prevent the deflection of the ball screw shaft, suppress vibration and noise, and operate at high speed with a simple configuration. Further, according to the ball screw shaft support structure described in claim 3, in the ball screw shaft support structure described in claim 2, a support member side roller is provided on the support member main body, and the support member is separated from and contacted with the ball screw shaft by rolling the support member side roller along the ball screw nut side inclined surface, so that the operation of the support member can be made smooth. Further, according to the ball screw shaft support structure described in claim 4, in the ball screw shaft support structure described in claim 2 or claim 3, a buffer material for the receiving member is inserted 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. Further, according to the ball screw shaft support structure described in claim 5, in the ball screw shaft support structure described in any one of claims 1 to 4, a buffer mechanism for buffering the approaching operation of the support member with respect to the ball screw shaft is provided, so that the deflection of the ball screw shaft can be prevented with a simple and compact configuration, vibration and noise can be suppressed, and it can operate at high speed. In particular, the buffer mechanism can suppress the sudden movement of the support member and prevent noise. Further, according to the actuator described in claim 6, since one support member of the ball screw shaft support structure described in any one of claims 1 to 5 is installed, the deflection of the ball screw shaft can be prevented with a simple and compact configuration, vibration and noise can be suppressed, and it can operate at high speed. Further, according to the actuator described in claim 7, since a plurality of support members of the ball screw shaft support structure described in any one of claims 1 to 5 are installed, even when the ball screw shaft is long, the deflection of the ball screw shaft can be prevented with a simple and compact configuration, vibration and noise can be suppressed, and it can operate at high speed.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Embodiments for Carrying Out the Invention

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

[0011] In addition, a ball screw shaft 9 is installed inside the base 3. Also, as shown in Fig. 1, there is a bearing portion 8a on the front end side (lower left side in Fig. 1) of the base 3, and a bearing portion 8b on the rear end side (upper right side in Fig. 2) of the base 3. The ball screw shaft 9 is supported by these bearing portions 8a, 8b. A spiral groove 9a is formed on the ball screw shaft 9.

[0012] As shown in FIGS. 1 and 2, a slider 11 is installed on the base 3 so as to be movable in the left-right direction. End caps 13, 13 are installed at both ends in the front-rear direction (the direction from the lower left to the upper right in FIG. 1) on one side in the width direction of the slider 11 (the upper left side in FIG. 1). Further, end caps 15, 15 are installed at both ends in the front-rear direction (the direction from the lower left to the upper right in FIG. 1) on the other side in the width direction of the slider 11 (the lower right side in FIG. 1) (the end cap on the rear end side is not shown). Return paths (not shown) are formed in the end caps 13, 15. Non-load circulation paths (not shown) are formed on both sides in the width direction (the direction from the upper left to the lower right in FIG. 1) within the slider 11. Further, guide grooves (not shown) are formed on both side surfaces in the width direction (the direction from the upper left to the lower right in FIG. 1) of the slider 11.

[0013] Steel balls (not shown) roll and circulate in the space between one non-load circulation path (not shown) within the slider 11, the return path of one end cap 13, the return path of the other end cap 13, and the guide groove 7 of one guide rail 5 and one guide groove (not shown) of the slider 11. Also, steel balls (not shown) roll and circulate in the space between the other non-load circulation path (not shown) within the slider 11, the return path of one end cap 15, the return path of the other end cap 15, and the guide groove 7 of the other guide rail 5 and the other guide groove (not shown) of the slider 11. With such a configuration, the slider 11 is movable with respect to the base 3.

[0014] Further, 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 includes 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 through the ball screw nut 31. A spiral groove 39 is formed on the inner peripheral surface of the ball screw nut body 33. Further, a no-load circulation path (not shown) is formed in the ball screw nut body 33, and return paths (not shown) are formed in the end caps 35 and 37.

[0015] Steel balls 41 are rolling and circulating in the no-load circulation path (not shown) of the ball screw nut body 33, the return paths (not shown) of the end caps 35 and 37, and the space between the spiral groove 39 of the ball screw nut body 33 and the 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] As shown in FIG. 2, on both sides in the width direction (both sides in the paper surface direction in FIG. 2) of the front end side (left side in FIG. 2) on the lower side of the slider 11, resin-made front rollers 21, 21 are rotatably installed as ball screw nut side rollers (the front roller 21 on the front side in FIG. 2 is not shown). Further, on both sides in the width direction (both sides in the paper surface direction in FIG. 2) of the rear end side (right side in FIG. 2) on the lower side of the slider 11, resin-made rear rollers 23, 23 are rotatably installed as ball screw nut side rollers (the rear roller 23 on the front side in FIG. 2 is not shown). Further, 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] Also, for example, as shown in FIGS. 2 and 4, a support member accommodating recess 51 is formed in the base 3. A ball screw shaft support structure 47 is installed in the support member accommodating recess 51. First, the ball screw shaft support structure 47 has a support member support member 50. The support member support member 50 has a base 53 for the support member. Support member base mounting plates 54, 54 are fixed to both front and rear end sides of the base 53 for the support member. 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 base 53 for the support member by fixing screws 58. The support member support member 50 has support member guide columns 55, 55. The support member guide columns 55, 55 are erected at both ends in the front-rear direction (left-right direction in FIG. 2) of the base 53 for the support member. The guide columns 55, 55 are fixed to the base 53 for the support member by fixing screws 56, 56. As shown in FIG. 2, a base accommodating hole 49 for the support member is formed at the bottom of the support member accommodating recess 51, and the base 53 for the support member is installed in the base accommodating hole 49 for the support member. 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, the base 53 for the support member, and thus the support member support member 50, is fixed to the base 3. Also, the support member support member 50 has a coil spring 65 as elastic means. The coil spring 65 is disposed between a support member 61, which will be described later, and the base 53 for the support member. Also, a U-shaped leaf spring 57, which is a part of a buffer mechanism to be described later, is installed at the center in the front-rear direction (left-right direction in FIG. 2) of the base 53 for the support member.

[0018] The above ball screw shaft support structure 47 has a support member 61. The above support member 61 is installed inside the support member accommodation recess 51 and above the base 53 for the support member. As shown in FIG. 5, the support member 61 has a support member main body 62, and guide through holes 63, 63 are formed at both ends in the front-rear direction (the direction from the lower left to the upper right in FIG. 5) of the support member main body 62. Slide bearings 64, 64 are press-fitted into the guide through holes 63, 63, and the support member guide struts 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 vertical direction along the support member guide struts 55, 55. Also, as shown in FIG. 2, a coil spring 65 as the above-described elastic means is stretched between the support member 61 and the base 53 for the support member. The support member 61 is constantly pressed and biased toward the ball screw shaft 9 side (the upper side in FIG. 2) by the coil spring 65. As described above, the support member support member 50 is composed of the base 53 for the support member, the base mounting plates 54, 54 fixed to the base 53 for the support member, the support member guide struts 55, 55, and the coil spring 65 that elastically supports the support member main body 62.

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

[0020] As shown in Fig. 2, when the slider 11 moves toward the support member 61 side and the front rollers 21, 21 roll onto the rear buffers 77, 77 of the rear inclined surfaces 73, 73, the support member 61 is pressed and biased downward in Fig. 6 against the elastic force of the coil spring 65. Also, when the slider 11 moves toward the support member 61 side from the side opposite to the direction shown in Fig. 2 and the rear rollers 23, 23 roll onto the front buffers 75, 75 of the front inclined surfaces 71, 71, the support member 61 is also pressed and biased 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 at the center on 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 includes, for example, a receiving member 83 made of POM (polyoxymethylene) and a buffer 87 for the receiving member 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 buffer 87 for the receiving member. Through holes 88, 88 with seat grooves are formed in the receiving member 83, 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 female screw portions 67, 67 formed in the support portion recess 79. The buffer 87 for the receiving member is fastened and fixed together with the receiving member 83 by the bolts 89, 89. Also, set screws 84, 84 are screwed in from the lower surface side of the support member main body 62 into the female screw portions 67, 67 formed in the support portion recess 79. By adjusting the screwing positions of the set screws 84, 84, excessive crushing of the buffer 87 for the receiving member is prevented, and the height of the receiving member 83 is adjusted. On the upper surface side of the receiving member 83, a recess 85 for receiving the ball screw shaft 9 is formed. Both sides in the width direction of the recess 85 of the receiving member 83 (in FIG. 5) are planar sliding portions 86, 86. As shown in FIG. 2, when the support member 61 is pressed and biased upward in FIG. 2 by the elastic force of the coil spring 65, 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 portion 81, and the deflection of the ball screw shaft 9 is prevented. Also, in front of the receiving member 83, a front inclined surface 82a that is substantially continuous with the front inclined surfaces 71, 71 of the front side of the support member main body 62 is formed, and behind the receiving member 83, a rear inclined surface 82b that is substantially continuous with the rear inclined surfaces 73, 73 of the rear side of the support member main body 62 is formed.

[0022] The felt-made buffer material 87 for the receiving member is for alleviating the impact when the receiving member 83 collides with the ball screw shaft 9. Also, on the lower surface side of the support member main body 62, for example, buffer materials 91, 91 made of low-rebound rubber for the support member are installed. These buffer materials 91, 91 for the support member alleviate the impact when the support member 61 collides with the base 53 for the support member. 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, the front buffer materials 75, 75 and the rear buffer materials 77, 77 installed on the front inclined surfaces 71, 71 and the rear inclined surfaces 73, 73 of the support member main body 62.

[0023] Also, as shown in FIG. 2, a U-shaped leaf spring 57, which is part of a buffer mechanism described later, is installed at the center in the front-rear direction (left-right direction in FIG. 2) of the base 53 for the support member, and is fixed to the base 53 for the support member by fixing screws 96, 96. Further, as shown in FIGS. 3 and 5, contact members 93, 93, which are part of a buffer mechanism described later, are fixed to both sides in the width direction (left-right direction in FIG. 3) of the support member 61. The support member 61 is inserted between both ends of the leaf spring 57 via the contact members 93, 93. A buffer mechanism 95 is constituted by the leaf spring 57 and the contact members 93, 93. The upward movement of the support member 61, that is, the operation of approaching the ball screw shaft 9, is buffered by the buffer mechanism 95.

[0024] Next, the operation according to this first embodiment will be described. When the ball screw shaft 9 is rotated and driven by the motor 43, the slider 11 moves forward and backward in the front-rear direction. In a state where the slider 11 is separated from the support member 61, as shown in FIG. 2, the support member 61 is pressed and biased 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 concave portion 85 of the receiving member 83 of the support portion 81, preventing the ball screw shaft 9 from deflecting.

[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 buffer materials 77, 77 on the rear inclined surfaces 73, 73 and start to roll. Thereby, the support member 61 is pressed and biased toward the side opposite to the ball screw shaft 9 (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 concave portion 85 of the receiving member 83 is released. The impact when the front rollers 21, 21 collide with the rear buffer materials 77, 77 is alleviated by the rear buffer materials 77, 77. FIG. 8 shows a state where the slider 11 further approaches the support member 61 side, and the support member 61 is further pressed and biased toward the side opposite to the ball screw shaft 9 (lower side in FIG. 8). When the slider 11 further moves to the left side in FIG. 8, the front rollers 21, 21 contact and roll on the rear inclined surfaces 82b, 82b of the receiving member 83, then contact and roll on the sliding portions 86, 86 of the receiving member 83, and further contact and roll on the front inclined surfaces 82a, 82a of the receiving member 83.

[0026] As shown in FIG. 9, when the slider 11 moves right above the support member 61, the front rollers 21, 21 separate from the receiving member 83, but the sliding portions 86, 86 of the receiving member 83 of the support member 61 are in 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 biased to the lowest position. The impact when the support member 61 collides with the base 53 for the support member is mitigated by the cushioning materials 91, 91 for the support member.

[0027] Next, when the slider 11 passes above the support member 61, the rear rollers 23, 23 of the slider 11 contact and roll on the rear inclined surfaces 82b, 82b, the sliding portions 86, 86, and the front inclined surfaces 82a, 82a of the receiving member 83, and then, via the front cushioning materials 75, 75 of the front inclined surfaces 71, 71, the support member 61 is pressed and biased against the elastic force of the coil spring 65 to the side of the anti-ball screw shaft 9 (lower side in FIG. 10). However, the pressing and biasing are gradually released as the slider 11 moves. Then, as shown in FIG. 10, when the slider 11 is moved to the left side in FIG. 10, again the support member 61 is pressed and biased 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 concave portion 85 of the receiving member 83 of the support portion 81, and the deflection of the ball screw shaft 9 is prevented. The impact when the receiving member 83 contacts the ball screw shaft 9 again is mitigated by the cushioning material 87 for the receiving member. In addition, the sudden upward movement when the support member 61 returns upward is mitigated because the leaf spring 57 of the buffer mechanism 95 contacts the contact member 93 and becomes a resistance, thereby preventing the generation of noise.

[0028] Also, the same applies when the slider 11 approaches and passes through the support member 61 from the side opposite to the direction shown in FIG. 2. In this case, the rear rollers 23, 23 of the slider 11 abut against the front side cushioning materials 75, 75 of the front side inclined surfaces 71, 71 of the support member 61 and roll, so that the support member 61 is pushed down against the biasing force of the coil spring 65. Also, the ball screw shaft support structure 47 can be attached to and detached from the support member housing recess 51 as one unit.

[0029] Next, the effects of this first embodiment will be described. First, the deflection of the ball screw shaft 9 can be prevented with a simple and compact configuration, and vibration and noise can be suppressed to cope with high speed operation. That is, the support member 61 having the receiving member 83 for supporting the ball screw shaft 9 is constantly biased toward the ball screw shaft 9 by the coil spring 65, and is configured to be appropriately pushed down by the cooperation of the front rollers 21, 21 and the rear rollers 23, 23 of the slider 11, the front side inclined surfaces 71, 71 and the rear side inclined surfaces 73, 73 of the support member 61. Also, since the cushioning material 87 for the receiving member is inserted 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 configuration. Also, since the receiving member 83 is detachably installed, it is easy to replace. Also, since the cushioning material 87 for the receiving member is made of felt, the configuration is simple and its cushioning effect and sound absorption effect are high. Also, since the cushioning materials 91, 91 for the support member are installed on the lower surface side of the support member 61, the impact when the support member 61 collides with the support member base 53 can be mitigated. Also, since the support member 61 is moved up and down by the cooperation of the front rollers 21, the rear rollers 23, the front side inclined surfaces 71, 71, and the rear side inclined surfaces 73, 73, the up and down movement of the support member 61 can be made smooth. In addition, since the front side inclined surfaces 71, 71 and the rear side inclined surfaces 73, 73 are provided with the front side buffer members 75, 75 and the rear side buffer members 77, 77, the impact when the front rollers 21 or the rear rollers 23 collide can be mitigated. Since the buffer members 91, 91 for the support members, the front side buffer members 75, 75, and the rear side buffer members 77, 77 are made of, for example, low-rebound rubber, a high buffer effect can be obtained with a simple configuration. In addition, since the buffer mechanism 95 is provided, a rapid rise of the support member 61 can be suppressed, the impact on the ball screw shaft 9 can be mitigated, and noise can be prevented. Further, since the buffer mechanism 95 is constituted by the leaf spring 57 and the contact members 93, 93, its configuration is also simple. In addition, since one support member 61 is installed in the actuator 1, its configuration is also simple.

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

[0031] The front side inclined surface member 103 is, for example, 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 as shown in FIG. 11(b). 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, whereby the support member 61 is pushed downward. Also, as shown in FIG. 5, a front side buffer material 75 and a rear side buffer material 77 are installed on the front side inclined surface 71 and the rear side inclined surface 73 of the support member main body 62, but buffer materials (not shown) may also be installed on the inclined surface 107 and the inclined surface 109. Moreover, there may be a case where buffer materials are not installed on the front side inclined surface 71 and the rear side inclined surface 73 of the support member main body 62, and buffer materials (not shown) are installed on the inclined surface 107 and the inclined surface 109. Note that the same reference numerals are given to the configurations common to those in the first embodiment, and the description thereof is omitted.

[0033] Next, a third embodiment of the present invention will be described with reference to FIG. 12. As shown in FIG. 12, the actuator 201 has front side inclined surface members 103, 103 and rear side inclined surface members 105, 105 installed below the slider 11 in the same manner as in the case of the second embodiment described above. A ball screw shaft support structure 203 is installed in the support member housing 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 has a support member main body 205. Guide through holes 207, 207 are formed at both ends of the support member main body 205 in the front-rear direction (the direction from the lower left to the upper right in FIG. 12(a)). Slide bearings 209, 209 are press-fitted into the guide through holes 207, 207, and support member guide posts 55, 55 are arranged so as to penetrate these slide bearings 209, 209 and are in sliding contact with the slide bearings 209, 209.

[0035] Support member side rollers 211 and 211 are rotatably installed at both ends of the support member main body 205 in the width direction (the direction from the upper left to the lower right in FIG. 12(a)). In the case of this third embodiment, the support member side rollers 211 and 211 abut against the inclined surfaces 107 of the front inclined surface member 103 and the inclined surfaces 109 of the rear inclined surface member 105 installed on the slider 11 and roll, so that the support member 204 is pressed downward and biased. Also, it is conceivable to install a buffer material (not shown) on the inclined surface 107 and the inclined surface 109. In addition, components that are common to those in the first embodiment are denoted by the same reference numerals and their descriptions are omitted.

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

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

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

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

[0040] The buffer mechanism 403 has a damper attachment member 405. As shown in FIG. 14(a), stepped through holes 407, 407 are provided at the center of the damper attachment member 405. The damper attachment 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. Also, as shown in FIG. 14(a), dampers 411, 411 are installed at both ends in the front-rear direction of the damper attachment member 405. The damper 411 has a cylinder 413 and a rod 415. Oil (not shown) is enclosed in the cylinder 413, and a piston (not shown) is fixed to the end of the rod 415 on the inner 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 relatively moved with respect to the rod 415. At this time, the movement of the support member 61 is buffered by the resistance of the oil (not shown) in the cylinder 413, and thus the movement of the cylinder 413 and, by extension, the support member 61 is buffered.

[0041] Next, referring to FIG. 15, a sixth embodiment of the present invention will be described. In this sixth embodiment, a ball screw shaft support structure 501 as shown in FIG. 15 is used. This ball screw shaft support structure 501 has substantially the same configuration as the ball screw shaft support structure 47 in the above-described first and second embodiments, but a buffer mechanism 503 is installed on the base 53 for the support member. The above-described buffer mechanism 503 has a rectangular plate 505 fixed to the base 53 for the support member. Dampers 507, 507, 507, 507 (the damper 507 at the left end in Fig. 15(a) is not shown) are installed at each corner of this plate 505. The damper 507 has the same configuration as the damper 411 in the fifth embodiment described above, and includes 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 vertical movement of the support member 61 in Fig. 15 is cushioned by the damper 507.

[0042] Next, a seventh embodiment of the present invention will be described with reference to Fig. 16. In the case of the first embodiment, the configuration in which one ball screw shaft support structure 47 is provided at one location in the axial direction was described as an example. However, in the case of the actuator 701 according to this seventh embodiment, the ball screw shaft support structures 47, 47 are respectively installed at two locations in the axial direction. Note that other configurations are the same as those in the first embodiment, and the same reference numerals are given to the same parts in the drawings and their descriptions are omitted.

[0043] In the case of this seventh embodiment, the same operations and effects as those in the first embodiment are achieved. However, in the case of this seventh embodiment, even if the ball screw shaft 9 is longer than that in the first embodiment, it is possible to prevent the ball screw shaft 9 from bending, suppress vibration and noise, and operate at high speed.

[0044] Note that the present invention is not limited to the first to seventh embodiments. First, in the case of the first to seventh embodiments, the case where one or two support members are provided was described, but it is not limited thereto, and the case where three or more support members are provided is also conceivable. In addition, as the material of the receiving member, various cases with good slidability such as oil-impregnated sintered materials in addition to POM are conceivable. In addition to felt and low-rebound rubber, the material of the cushioning material can be various cases such as other fabrics, rubber, resin, gel-like materials, porous materials such as sponges, etc. In addition to resin, the material of the roller can be various cases such as rubber, oil-impregnated sintered materials, etc. Also, the base for the support member can be integrated with the base of the actuator, and the support member guide column can be directly fixed to the base. In addition, the illustrated configuration is merely an example.

Industrial Applicability

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

Explanation of Reference Numerals

[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 buffer mechanism) 61 Support member 65 Coil spring (elastic means) 71 Front inclined surface 73 Rear inclined surface 81 Support part 83 Receiving member 87 Cushioning material for the receiving member 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 onto the ball screw shaft, a support member detachably installed on the ball screw shaft and pressed against the ball screw shaft by elastic means, and separated from the ball screw shaft against the biasing force of the elastic means by the approach of the ball screw nut, comprising: both sides along the axial direction of the ball screw shaft on the ball screw nut side are provided with ball screw nut side inclined surfaces, and an inclined surface buffer material is installed on the ball screw nut side inclined surface, characterized in that it is a ball screw shaft support structure.

2. In the ball screw shaft support structure according to Claim 1, the support member is composed of a support member main body and a receiving member for receiving the ball screw shaft, characterized in that it is a ball screw shaft support structure.

3. In the ball screw shaft support structure according to Claim 2, a support member side roller is provided on the support member main body, and the support member is separated from the ball screw shaft by rolling the support member side roller along the ball screw nut side inclined surface, characterized in that it is a ball screw shaft support structure.

4. In the ball screw shaft support structure according to Claim 2 or Claim 3, a buffer material for the receiving member is inserted between the support member main body and the receiving member, characterized in that it is a ball screw shaft support structure.

5. In the ball screw shaft support structure according to any one of Claims 1 to 4, a buffer mechanism for buffering the approaching movement of the support member with respect to the ball screw shaft is provided, characterized in that it is a ball screw shaft support structure.

6. An actuator, characterized in that one support member of the ball screw shaft support structure according to any one of Claims 1 to 5 is installed.

7. An actuator, characterized in that a plurality of support members of the ball screw shaft support structure according to any one of Claims 1 to 5 are installed.

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