Ball screw shaft support structure and actuator

Abstract

To provide a ball screw shaft support structure which achieves high flexibility of the installation attitude and can prevent deflection of a ball screw shaft to inhibit vibration and noise and enable high speed action 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 which is threadedly engaged with the ball screw shaft in a movable manner; and a support member which is installed in a manner that the support member can contact with or separate 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 a biasing force of the elastic means by the ball screw nut moving close thereto. The ball screw shaft is made of a magnetic material and the support member is provided with a magnet which attracts the ball screw shaft.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a ball screw shaft support structure and actuator, and in particular to one that has a high degree of freedom in installation position and a simple, compact configuration that can prevent bending of the ball screw shaft and suppress vibration and noise while enabling it to 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] Furthermore, in the ball screw shaft support structure and actuator described in Patent Document 2, a support member is biased by an elastic means to support the ball screw shaft, and when the slider approaches, the support member retracts against the elastic force of the elastic means so as not to impede the movement of the slider. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Utility Model Application Publication No. 7-3936 [Patent Document 2] Patent Publication No. 2021-76195 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the above conventional configuration has the following problems. That is, 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 comes into sliding contact with the inclined surface of the slider is also attached, and there is a problem that the support part and its surrounding structure are complicated. Also, when the long lead screw is installed in an upright orientation or when the support part is installed in an orientation below the long lead screw, the long lead screw is not properly supported and bending cannot be prevented, which results in a problem of limited freedom of installation orientation. Similarly, with the ball screw shaft support structure and actuator described in Patent Document 2, when the ball screw shaft is installed in an upright position or when the ball screw shaft support structure is installed in an orientation below the ball screw shaft, the ball screw shaft is not properly supported, resulting in a problem of limited freedom of installation position.

[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 has a high degree of freedom in installation posture, is capable of preventing bending of the ball screw shaft with a simple and compact configuration, and is capable of suppressing vibration and noise and accommodating higher speeds. [Means for solving the problem]

[0007] In order to solve the above problems, a ball screw shaft support structure according to claim 1 of the present invention comprises a base, a ball screw shaft rotatably installed relative to the base, a ball screw nut movably screwed to the ball screw shaft, and a support member installed between the base and the ball screw shaft so as to be able to approach and releasably contact 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, wherein the ball screw shaft is a magnetic body, and a magnet that attracts the ball screw shaft is provided on the support member. The support member is installed in such a position that it is located above the ball screw shaft. The present invention is characterized in that: Furthermore, 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, a stopper is provided to restrict movement of the support member toward the ball screw shaft. The ball screw shaft support structure according to claim 3 is the ball screw shaft support structure according to claim 2, characterized in that a buffer member is provided between the support member and the stopper. Furthermore, the ball screw shaft support structure according to claim 4 is characterized in that, in the ball screw shaft support structure according to any one of claims 1 to 3, a buffer member is installed between the magnet and the support member. A ball screw shaft support structure according to claim 5 is characterized in that one support member of the ball screw shaft support structure according to any one of claims 1 to 4 is provided. A ball screw shaft support structure according to claim 6 is characterized in that a plurality of support members of the ball screw shaft support structure according to any one of claims 1 to 4 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 base, a ball screw shaft rotatably installed relative to the base, a ball screw nut movably screwed to the ball screw shaft, and a support member installed between the base and the ball screw shaft so as to be able to approach and separate from the ball screw shaft, pressed against the ball screw shaft by elastic means, and separated from the ball screw shaft against the biasing force of the elastic means when the ball screw nut approaches, the ball screw shaft being a magnetic body and the support member being provided with a magnet that attracts the ball screw shaft, so that the ball screw shaft can be installed with a high degree of freedom in its orientation, and the simple and compact structure can prevent the ball screw shaft from bending, suppress vibrations and noise, and operate at high speed. In particular, the cushioning mechanism can suppress abrupt movement of the support member, thereby preventing noise. Furthermore, according to the ball screw shaft support structure of claim 2, in the ball screw shaft support structure of claim 1, a stopper is provided to restrict movement of the support member toward the ball screw shaft, so that a simple configuration can be used to suppress sudden movement of the support member and prevent noise. According to the ball screw shaft support structure of claim 3, in the ball screw shaft support structure of claim 2, a buffer member is installed between the support member and the stopper, so that sudden movement of the support member can be suppressed with a simple configuration, thereby preventing noise. Furthermore, according to the ball screw shaft support structure described in claim 4, in the ball screw shaft support structure described in any one of claims 1 to 3, a buffer member is installed between the magnet and the support member, so that the impact when the receiving member collides with the ball screw shaft can be mitigated with a simple configuration. Furthermore, according to the ball screw shaft support structure of claim 5, one support member of the ball screw shaft support structure of any one of claims 1 to 4 is provided, so that replacement is easy. Furthermore, according to the ball screw shaft support structure described in claim 6, a plurality of support members of the ball screw shaft support structure described in any one of claims 1 to 4 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. Furthermore, according to the actuator of claim 7, in the actuator of claim 5 or claim 6, the support member is installed in an orientation such that it is above the ball screw shaft. Therefore, even if the actuator is installed in a suspended state, the simple and compact configuration prevents bending of the ball screw shaft, suppresses vibration and noise, and allows for high-speed operation. Furthermore, according to the actuator of claim 8, in the actuator of claim 5 or claim 6, the ball screw shaft is installed in an upright position. Therefore, even when the actuator is installed upright, the simple and compact configuration prevents bending of the ball screw shaft, suppresses vibration and noise, and allows for 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 in which a part of the front side of an actuator is removed and the vicinity of a support member is enlarged. [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 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 8] 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 9] 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 10] FIG. 11 is a perspective view of an actuator according to a second embodiment of the present invention. [Figure 11] FIG. 13 is a perspective view of a ball screw shaft support structure according to a third 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 9. Fig. 1 is a perspective view showing the overall configuration of an actuator 1 according to the 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, the actuator 1 has a base 3 having a substantially U-shaped cross section, and the actuator 1 is used in a state in which the base 3 is fixed to a ceiling (not shown) and hung upside down. Guide rails 5, 5 are provided on both the left and right inner 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, a bearing portion 11 is provided at the front end side (upper right side in Fig. 1) of the base 3, and a bearing portion 13 is provided at the rear end side (lower left side in Fig. 1) of the base 3. The ball screw shaft 9 is journaled by these bearing portions 11 and 13. A spiral groove 15 is formed in the ball screw shaft 9.

[0012] As shown in Figs. 1 and 2, the slider 17 is installed on the base 3 so as to be movable in the left-right direction. Guide returns 19, 19 are installed on both ends of the slider 17 in the front-rear direction (direction from the lower left to the upper right in Fig. 1) on one side of the width direction (lower right side in Fig. 1). Guide returns 21, 21 are installed on both ends of the slider 17 in the front-rear direction (direction from the lower left to the upper right in Fig. 1) on the other side of the width direction (upper left side in Fig. 1) (the guide return on the rear end side is not shown). A return path (not shown) is formed in the guide returns 19, 21. Unloaded circulation paths (not shown) are formed on both sides of the slider 17 in the width direction (direction from the upper left to the lower right in Fig. 1). Guide grooves (not shown) are formed on both side surfaces of the slider 17 in the width direction (direction from the upper left to the lower right in Fig. 1).

[0013] Steel balls (not shown) roll and circulate in one unloaded circulation path (not shown) in the slider 17, the return path of the one guide return 19, the return path of the other guide return 19, and the space between the guide groove 7 of the one guide rail 5 and one guide groove (not shown) of the slider 17. Steel balls (not shown) roll and circulate in the other unloaded circulation path (not shown) in the slider 17, the return path of the one guide return 21, the return path of the other guide return 21, and the space between the guide groove 7 of the other guide rail 5 and the other guide groove (not shown) of the slider 17. With this configuration, the slider 17 is movable relative to the base 3.

[0014] As shown in Fig. 2, the slider 17 has a ball screw nut accommodating member 23, and a ball screw nut 25 is fixed in the ball screw nut accommodating member 23. The ball screw nut 25 has a ball screw nut body 27, an end cap 29 on the front end side (left side in Fig. 2), and an end cap 31 on the rear end side (right side in Fig. 2). The ball screw shaft 9 passes through the ball screw nut 25. A spiral groove 33 is formed on the inner peripheral surface of the ball screw nut body 27. An unloaded circulation path (not shown) is formed in the ball screw nut body 27, and a return path (not shown) is formed in the end caps 29 and 31.

[0015] Steel balls 35 roll and circulate in an unloaded circulation path (not shown) of the ball screw nut body 27, in return paths (not shown) of the end caps 29, 31, and in a space between the spiral groove 33 of the ball screw nut body 27 and the spiral groove 15 of the ball screw shaft 9. As shown in FIG. 1, a motor 37 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 37. When the ball screw shaft 9 is rotated and driven, the slider 17 is moved in the front-rear direction (left-right direction in FIG. 2).

[0016] 2, front rollers 39, 39 made of resin, for example, are rotatably installed 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) of the upper side of the slider 17 in FIG. 2 (the front roller 39 on the front side in FIG. 2 is not shown). Rear rollers 41, 41 made of resin, for example, are rotatably installed 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) of the upper side of the slider 17 in FIG. 2 (the rear roller 41 on the front side in FIG. 2 is not shown). Plate-shaped upper surface side sliding members 43, 43 are installed on both ends in the width direction (both sides in the paper surface direction in FIG. 2) of the slider 17 on the upper side of FIG. 2 (the upper surface side sliding member 43 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 45. A ball screw shaft support structure 47 is installed in the support member accommodating recess 45. The ball screw shaft support structure 47 includes a support member support member 49. The support member support member 49 includes a support member base 51. Support member base mounting plates 53, 53 are fixed to both front and rear ends of the support member base 51. Through holes 55, 55 are formed at both ends of the support member base mounting plate 53. The support member base mounting plates 53, 53 are fixed to the support member base 51 by fixing screws 57. The support member support member 49 includes support member guide pillars 59, 59. The support member guide pillars 59, 59 are erected at both ends of the support member base 51 in the front-rear direction (left-right direction in FIG. 2). The support member guide columns 59, 59 are fixed to the support member base 51 by fixing screws 61, 61. As shown in FIG. 2, a support member base accommodating hole 63 is formed in the bottom of the support member accommodating recess 45, and the support member base 51 is placed in the support member base accommodating hole 63. The support member base 51, and therefore the support member support member 49, are fixed to the base 3 by passing a fixing screw 65 through the through hole 55 of the support member base mounting plate 53 and screwing it into the base 3. Further, the support member supporting member 49 has a coil spring 67 as an elastic means. The coil spring 67 is stretched between a support member 71 (to be described later) and the support member base 51. Further, a U-shaped leaf spring 69 which is part of a shock-absorbing mechanism to be described later is provided at the center of the support member base 51 in the front-rear direction (left-right direction in FIG. 2).

[0018] The ball screw shaft support structure 47 includes a support member 71. The support member 71 is installed in the support member accommodating recess 45 on the lower side of the support member base 51 in FIG. 2. As shown in FIG. 5, the support member 71 includes a support member body 73, and guide through holes 75, 75 are formed on both ends of the support member body 73 in the front-rear direction (the direction from the lower left to the upper right in FIG. 5). Slide bearings 77, 77 are press-fitted into the guide through holes 75, 75, and the support member guide pillars 59, 59 are arranged to penetrate the slide bearings 77, 77 and are in sliding contact with the slide bearings 77, 77. The support member 71 is movable in the up-down direction along the support member guide pillars 59, 59. In addition, as shown in FIG. 2, a coil spring 67 is stretched between the support member 71 and the support member base 51 as the elastic means. The support member 71 is constantly pressed and urged toward the ball screw shaft 9 side (the lower side in FIG. 2) by the coil spring 67 . As described above, the support member support member 49 is composed of the support member base 51, the support member base mounting plates 53, 53 fixed to the support member base 51, the support member guide pillars 59, 59, and the coil spring 67 which elastically supports the support member main body 73. Further, support member stoppers 79, 79 are provided on the front and rear end sides of the support member accommodating recess 45 of the base 3. The tip side of the support member stopper 79 is bent to form an engagement portion 81. A buffer member 83 is provided on the engagement portion 81. Stopper engagement portions 85, 85 with which the engagement portions 81, 81 of the support member stoppers 79, 79 engage via the buffer members 83, 83 are provided on both front and rear ends of the support member 71, respectively. The support member stoppers 79, 79 and the stopper engagement portions 85, 85 prevent the support member 71 from being spaced apart from the support member base 51 by more than a predetermined distance.

[0019] Front inclined surfaces 87, 87 are formed on both sides in the width direction (direction from upper left to lower right in FIG. 5) of the front (upper right in FIG. 5) of the upper surface side of the support member main body 73, and rear inclined surfaces 89, 89 are formed on both sides in the width direction (direction from upper left to lower right in FIG. 5) of the rear (lower left in FIG. 5) of the upper surface side of the support member main body 73. The support member 71 has front buffer members 91, 91 and rear buffer members 93, 93 made of, for example, low-resilience rubber. The front buffer members 91, 91 are installed on the front inclined surfaces 87, 87, and the rear buffer members 93, 93 are installed on the rear inclined surfaces 89, 89.

[0020] As shown in Fig. 2, when the slider 17 moves toward the support member 71 and the front rollers 39 roll against the rear buffer members 93 of the rear inclined surfaces 89, the support member 71 is pressed and urged upward in Fig. 6 against the elastic force of the coil spring 67. Also, when the slider 17 moves toward the support member 71 from the side opposite to the direction shown in Fig. 2 and the rear rollers 41 roll against the front buffer members 91 of the front inclined surfaces 87, the support member 71 is pressed and urged upward in Fig. 6 against the elastic force of the coil spring 67.

[0021] Further, the support member 71 has a support portion 95. A support portion recess 97 is formed in the center of the upper surface side of the support member main body 73, and the support portion 95 is installed in this support portion recess 97. The support portion 95 has a receiving member 99 made of, for example, POM (polyoxymethylene). The receiving member 99 is disposed on the lower side in FIG. 2 and is adapted to receive the ball screw shaft 9. The receiving member 99 has through holes 103, 103 with countersunk holes, and the receiving member 99 is detachably fixed in the support portion recess 97 by passing bolts 105, 105 through the through holes 103, 103 and screwing them into female threaded portions 107, 107 formed in the support portion recess 97. The female threaded portions 107, 107 formed in the support portion recess 97 are stepped through holes whose diameters are enlarged on the lower side in FIG. 3, and the height of the receiving member 99 is set by appropriately setting the depth of the stepped portion. A recess 111 for receiving the ball screw shaft 9 is formed on the lower surface side of the receiving member 99. Both sides (in FIG. 5) of the recess 111 of the receiving member 99 in the width direction are formed as flat sliding portions 113, 113. In addition, a front side inclined surface 115 that is approximately continuous with the front side inclined surfaces 87, 87 of the support member main body 73 is formed in front of the receiving member 99, and a rear side inclined surface 117 that is approximately continuous with the rear side inclined surfaces 89, 89 of the support member main body 73 is formed in rear of the receiving member 99. Further, a magnet accommodating portion 119 is formed inside the receiving member 99, and a magnet 121 is accommodated inside this magnet accommodating portion 119. As shown in Fig. 2, when the support member 71 is pressed and urged downward in Fig. 2 by the elastic force of the coil spring 67, the recess 111 of the receiving member 99 of the support portion 95 comes into contact with the vicinity of the center of the ball screw shaft 9, and the ball screw shaft 9 is attracted by the magnet 121, thereby supporting the ball screw shaft 9 and preventing the ball screw shaft 9 from bending. Further, the tip of the coil spring 67 is in contact with the magnet 121 via a magnet cushioning member 123. This serves to reduce the impact when the support portion 95 comes into contact with the ball screw shaft 9.

[0022] A cushioning member 125 for support members made of, for example, low-resilience rubber is provided on the lower surface side of the support member main body 73. These cushioning members 125 for support members cushion the impact when the support member 71 collides with the support member base 51. As described above, the support member 71 is composed of the support member main body 73, the support portion 95 installed on the support member main body 73, and the front side buffer members 91, 91 and rear side buffer members 93, 93 installed on the front side inclined surfaces 87, 87 and the rear side inclined surfaces 89, 89 of the support member main body 73.

[0023] As shown in FIG. 2, a U-shaped leaf spring 69, which is a part of a cushioning mechanism described later, is installed in the center of the support member base 51 in the front-rear direction (left-right direction in FIG. 2), and is fixed to the support member base 51 by fixing screws 127, 127. As shown in FIG. 3 and FIG. 5, abutment members 129, 129, which are a part of a cushioning mechanism described later, are fixed to both sides of the support member 71 in the width direction (left-right direction in FIG. 3). The support member 71 is inserted between both ends of the leaf spring 69 via the abutment members 129, 129. The leaf spring 69 and the abutment members 129, 129 form a cushioning mechanism 131. The cushioning mechanism 131 cushions the upward movement of the support member 71, i.e., the movement of the support member 71 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 37, the slider 17 advances and retreats in the front-rear direction. In a state in which the slider 17 is separated from the support member 71, as shown in Fig. 2, the support member 71 is pressed and urged downward in Fig. 2 by the elastic force of the coil spring 67, and the recess 111 of the receiving member 99 of the support portion 95 is brought into contact with the ball screw shaft 9, and the ball screw shaft 9 is attracted to the support member 71 side by the magnet 121, thereby supporting the vicinity of the center of the ball screw shaft 9 and preventing the ball screw shaft 9 from bending. In addition, support member stoppers 79, 79 are installed on the base 3, and stopper engagement portions 85, 85 are provided on the support member 71, so that the support member 71 is not spaced apart from the support member base 51 by more than a predetermined distance. This prevents a load from being applied to the ball screw shaft 9, allowing the slider 17 to operate smoothly.

[0025] As shown in FIG. 6, when the slider 17 approaches the support member 71 from the right side in FIG. 6, the front rollers 39, 39 come into contact with the rear buffer members 93, 93 of the rear inclined surfaces 89, 89 and start rolling. As a result, the support member 71 is pressed and urged toward the anti-ball screw shaft 9 side (upper side in FIG. 6) against the elastic force of the coil spring 67, and the support of the ball screw shaft 9 by the recess 111 of the receiving member 99 is released. The impact when the front rollers 39, 39 collide with the rear inclined surfaces 89, 89 is mitigated by the rear buffer members 93, 93. FIG. 7 shows a state in which the slider 17 approaches further toward the support member 71, and the support member 71 is further pressed and urged toward the anti-ball screw shaft 9 side (upper side in FIG. 7). When the slider 17 moves further to the left in Figure 7, the front rollers 39, 39 abut against the rear inclined surfaces 117, 117 of the receiving member 99 and roll, then abut against the sliding portions 113, 113 of the receiving member 99 and roll, and further abut against the front inclined surfaces 115, 115 of the receiving member 99 and roll.

[0026] As shown in Fig. 8, when the slider 17 moves directly above the support member 71, the front rollers 39, 39 move away from the receiving member 99, but the sliding parts 113, 113 of the receiving member 99 of the support member 71 come into sliding contact with the upper surface side sliding members 43, 43 of the slider 17. At this time, the support member 71 is pressed and urged furthest toward the anti-ball screw shaft 9 side (upper side in Fig. 8). The impact when the support member 71 collides with the support member base 51 is mitigated by the support member buffer members 125, 125.

[0027] Next, as the slider 17 passes under the support member 71, the rear rollers 41, 41 of the slider 17 roll against the rear inclined surfaces 117, 117, sliding portions 113, 113, and front inclined surfaces 115, 115 of the receiving member 99, and then press and urge the support member 71 toward the anti-ball screw shaft 9 side (upper side in Figure 9) against the elastic force of the coil spring 67 via the front buffer members 91, 91 of the front inclined surfaces 87, 87, but as the slider 17 moves, this pressing and urging is gradually released. Then, as shown in FIG. 9, when the slider 17 is moved to the left in FIG. 9, the support member 71 is again pressed and urged downward in FIG. 9 by the elastic force of the coil spring 67, and the vicinity of the center of the ball screw shaft 9 is attracted and supported by the magnet 121 in the recess 111 of the receiving member 99 of the support portion 95, thereby preventing the ball screw shaft 9 from bending. In addition, the sudden rise of the support member 71 when it returns to the ball screw shaft 9 side (the lower side in FIG. 9) is mitigated by the contact between the leaf spring 69 of the buffer mechanism 131 and the abutment member 129, which creates resistance, thereby preventing the generation of noise. In addition, the magnet buffer member 123 also mitigates the impact when the support part 95 comes into contact with the ball screw shaft 9.

[0028] The same applies when the slider 17 approaches and passes over the support member 71 from the opposite side to the direction shown in Fig. 2. In this case, the rear rollers 41, 41 of the slider 17 come into contact with the front buffer members 91, 91 of the front inclined surfaces 87, 87 of the support member 71 and roll, so that the support member 71 is pressed down against the biasing force of the coil spring 67. Moreover, the ball screw shaft support structure 47 is structured so as to be detachable from the support member accommodating recess 45 as a single unit.

[0029] Next, the effects of the first embodiment will be described. First, even if the actuator 1 is fixed to a ceiling (not shown) and installed in a state of being hung upside down, the simple and compact configuration can prevent bending of the ball screw shaft 9, and can suppress vibration and noise to accommodate higher speeds. That is, the support member 71 having a receiving member 99 that supports the ball screw shaft 9 is constantly urged toward the ball screw shaft 9 by the coil spring 67, and the ball screw shaft 9 is attracted to the support member 71 by the magnet 121, and when the slider 17 approaches the support member 71, the support member 71 is appropriately pushed down by cooperation of the front rollers 39, 39 and rear rollers 41, 41 of the slider 17 and the front inclined surfaces 87, 87 and rear inclined surfaces 89, 89 of the support member 71. In addition, support member stoppers 79, 79 are provided on the base 3, and stopper engagement portions 85, 85 are provided on the support member 71, so that the support member 71 is not spaced apart from the support member base 51 by more than a predetermined distance, preventing load from being applied to the ball screw shaft 9 and enabling the slider 17 to operate smoothly. Moreover, since the receiving member 99 is detachably installed, it can be easily replaced. Moreover, since the support member cushioning members 125, 125 are also provided on the lower surface side of the support member 71, the impact when the support member 71 collides with the support member base 51 can be mitigated. In addition, since the support member 71 is raised and lowered by cooperation of the front roller 39, the rear roller 41, the front inclined surfaces 87, 87, and the rear inclined surfaces 89, 89, the raising and lowering movement of the support member 71 can be made smooth. In addition, front side buffer members 91, 91 and rear side buffer members 93, 93 are provided on the front side inclined surfaces 87, 87 and rear side inclined surfaces 89, 89, so that the impact when the front roller 39 or the rear roller 41 collides can be mitigated. The support member cushioning members 125, 125, the front side cushioning members 91, 91 and the rear side cushioning members 93, 93 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 131 is provided, a sudden rise of the support member 71 can be suppressed, the impact on the ball screw shaft 9 can be reduced, and noise can be prevented. In addition, since the buffer mechanism 131 is composed of the leaf spring 69 and the abutment members 129, 129, the configuration is also simple. Furthermore, since the actuator 1 is provided with one support member 71, the structure is simple.

[0030] Next, a second 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 201 according to this second 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.

[0031] The second embodiment also provides the same actions and effects as the first embodiment, but even if the ball screw shaft 9 is longer than in the first embodiment, the second embodiment prevents bending of the ball screw shaft 9, suppresses vibration and noise, and allows for high-speed operation.

[0032] Next, a third embodiment of the present invention will be described with reference to FIG. In the case of the third embodiment, a support member 301 is provided. The support member 301 has a configuration substantially similar to that of the support member 71 in the first embodiment described above, but a support member stopper 303 and a stopper engagement member 305 are provided. The stopper engagement members 305 are provided on both sides in the width direction of the support member main body 73. The stopper engagement members 305 have an L-shaped cross section, and are formed with protruding portions 307 that protrude from both sides in the width direction of the support member main body 73. The support member stopper 303 is provided on the support member base 51. The tip of the support member stopper 303 extends outward, and a through hole 311 is formed that is penetrated by the protruding portion 307, and a contact portion 313 is provided against which the protruding portion 307 contacts when the support member 71 descends. A buffer member 315 is provided on the side of the abutting portion 313 against which the protruding portion 307 contacts. In the third embodiment, the support member stoppers 79, 79 are not provided. The other configurations are the same as those of the first embodiment, and the same parts in the drawings are given the same reference numerals and their explanation is omitted.

[0033] This third embodiment also achieves the same functions and effects as the first and second embodiments, but instead of support member stoppers 79, 79, a support member stopper 303 and a stopper engagement member 305 are provided, and when the support member 71 is lowered, the protrusion 307 of the stopper engagement member 305 abuts against the abutment portion 313 of the support member stopper 303, and the support member 71 does not move away from the support member base 51 by more than a predetermined distance, so that the slider 17 can be operated smoothly without applying a load to the ball screw shaft 9. In addition, since a cushioning member 315 is provided on the side of the abutment portion 313 against which the protrusion 307 abuts, the cushioning member 315 can absorb the impact generated when the support member 71 descends and the protrusion 307 of the stopper engagement member 305 abuts against the abutment portion 313 of the support member stopper 303, thereby preventing noise and vibration.

[0034] The present invention is not limited to the first to third embodiments. First, in the first to third embodiments, the cases where one or three support members are provided have been described, but this is not limited to this, and cases where two or four or more support members are provided are also contemplated. 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 member may be various other than felt or low-resilience rubber, such as cloth, rubber, resin, gel material, sponge or other porous material. The roller may be made of various materials such as rubber, metal, 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]

[0035] The present invention relates to a ball screw shaft support structure and actuator, and in particular to one that has a high degree of freedom in installation position and a simple, compact configuration that prevents bending of the ball screw shaft, suppresses vibration and noise, and enables high-speed operation, and is suitable for, for example, industrial robots. [Explanation of symbols]

[0036] 1 Actuator 3. Bass 9 Ball screw shaft 17 Slider 25 Ball screw nut 67 Coil spring (elastic means) 71 Support material 79 Support member stopper 83 Cushioning materials 121 Magnet 123 Cushioning materials for magnets 201 Actuator 301 Support material

Claims

1. With the base, A ball screw shaft rotatably installed relative to the base; a ball screw nut movably screwed to the ball screw shaft; a support member disposed between the base and the ball screw shaft so as to be capable of coming into contact with and being separated from the ball screw shaft by an elastic means, and which is pressed against the ball screw shaft by the approach of the ball screw nut against the biasing force of the elastic means; Equipped with The ball screw shaft is made of a magnetic material. The support member is provided with a magnet that attracts the ball screw shaft, A ball screw shaft support structure, characterized in that the support member is installed in an orientation such that it is above the ball screw shaft.

2. 2. The ball screw shaft support structure according to claim 1, A ball screw shaft support structure comprising: a stopper for restricting movement of the support member toward the ball screw shaft.

3. 3. The ball screw shaft support structure according to claim 2, A ball screw shaft support structure, characterized in that a buffer member is installed between the support member and the stopper.

4. In the ball screw shaft support structure according to any one of claims 1 to 3, A ball screw shaft support structure, characterized in that a buffer member is installed between the magnet and the support member.

5. An actuator comprising one support member of the ball screw shaft support structure according to any one of claims 1 to 4.

6. 5. An actuator comprising a plurality of support members of the ball screw shaft support structure according to claim 1.

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