TW201723349A - Ball screw type driving unit and movable body floating unit - Google Patents

Abstract

A ball screw type driving unit includes a connector (7) that connects a nut (3) and a movable body in an axial direction having a plurality of balls (7) in between. The connector (7) includes a rolling body arrangement groove (72) that arranges the plurality of balls (71) in a circumferential direction of a screw shaft (2). The rolling body arrangement groove (72) is formed in either a non-circular viewed in the axial direction or a circular having a center does not match an axial center (C) of the ball screw (2) viewed in the axial direction.

Description

Ball screw drive unit and movable body floating unit

The present invention relates to a ball screw type driving device and a movable body floating unit. The present application claims priority based on Japanese Patent Application No. 2015-177619, filed on Sep. 2011.

Patent Document 1 discloses a ball screw type driving device. The ball screw type drive device includes a nut member that is movably supported by the guide portion. The movable body is reciprocally driven along the guide portion via the nut member by the reciprocal rotation of the screw shaft screwed to the nut member. The ball screw type drive device is a first bolt bearing that is fixed to the movable body by the circumferential direction and is movably fitted to the mounting hole of the nut member, and a first thrust bearing that is interposed between the movable body and the nut member, and The nut member is supported to be movable in the radial direction with respect to the movable body and absorbs vibration when the screw shaft rotates, via the second thrust bearing between the nut member and the mounting bolt. [Prior Art Document] [Patent Document] [Patent Document 1] Japanese Patent Laid-Open No. 2011-2047

[Problem to be Solved by the Invention] The ball screw type drive device having the above configuration has a thrust bearing between the nut member and the movable body. Therefore, the mounting bolt fixed to the movable body is inserted into the mounting hole of the nut member, and the rotation of the nut member is restricted by the mounting bolt (refer to paragraph 0023 of Patent Document 1). However, if the rotation of the thrust bearing is restricted by the mounting bolt, the mounting bolt and the nut member are restrained, and the vibration at the time of the rotation of the screw shaft is directly transmitted to the movable body via the nut member and the mounting bolt. As described above, in the above configuration, the floating function of the thrust bearing is meaningless, and the possibility of vibration when the screw shaft rotates cannot be absorbed. The present invention provides a ball screw type driving device and a movable body floating unit that can restrict the rotation of the nut member and absorb the vibration transmitted to the screw shaft of the movable body. [Technical means for solving the problem] According to a first aspect of the present invention, a ball screw type driving device includes: a screw shaft having a spiral rolling element rolling groove on an outer peripheral surface; and a nut member having the inner circumferential surface and the above a rolling element load rolling groove facing the spiral rolling groove; a plurality of first rolling elements interposed between the rolling element rolling groove and the rolling element load rolling groove; and a movable body which can be combined with the nut a member that moves together to support the movable body in an axial direction in which the screw shaft extends; and a connector that connects the nut member and the movable body via a plurality of second rolling elements in the axial direction . The connector has a rolling element arrangement groove in which the plurality of second rolling elements are arranged in the circumferential direction of the screw shaft. The rolling element arrangement groove is formed in a non-circular shape as viewed in the axial direction, or is formed in a circular shape in which the center does not coincide with the axial center of the screw shaft as viewed in the axial direction. According to the second aspect of the present invention, the flange member can be integrally formed in the nut member. The rolling element arrangement groove may include: a first rolling element arrangement groove disposed on one side of the axial direction of the flange portion; and a second rolling element arrangement groove disposed in the axial direction of the flange portion The other side. The connector has a pair of plate members that sandwich the flange portion via the plurality of second rolling elements disposed in the first rolling element arrangement groove and the second rolling element arrangement groove, and the pair of plate members At least one of the attachment portions may be detachably attached to the movable body. According to a third aspect of the present invention, the connector can be attached to the mounting plate of the movable body. The rolling element arrangement groove may include a first rolling element arrangement groove disposed on one surface of the mounting plate in the axial direction, and a second rolling element arrangement groove disposed on the other surface of the mounting plate in the axial direction. The connector has a pair of plate members sandwiching the mounting plate via the plurality of second rolling elements disposed in the first rolling element arrangement groove and the second rolling element arrangement groove, and at least the pair of plate members Either the attachment portion that is detachably attached to the nut member may be attached. According to a fourth aspect of the present invention, each of the first rolling element arrangement groove and the second rolling element arrangement groove is in contact with the second rolling element at a specific contact angle with respect to a radial direction of the screw shaft. The contact angle between the first rolling element arrangement groove and the second rolling element arrangement groove may be set to a bevel type of the front combination. According to a fifth aspect of the invention, the contact angle α between the first rolling element arrangement groove and the second rolling element arrangement groove satisfies a relationship of 45° < α < 90°. According to a sixth aspect of the present invention, a movable body floating unit provided in a ball screw type driving device includes: a screw shaft having a spiral rolling element rolling groove on an outer circumferential surface; and a nut member having the inner circumferential surface and the above a rolling element load rolling groove facing the spiral rolling groove; a plurality of first rolling elements interposed between the rolling element rolling groove and the rolling element load rolling groove; and a movable body which can be combined with the nut a member that moves together to support the movable body in an axial direction in which the screw shaft extends; and a connector that connects the nut member and the movable body via a plurality of second rolling elements in the axial direction . The connector has a rolling element arrangement groove in which the plurality of second rolling elements are arranged in the circumferential direction of the screw shaft. The rolling element arrangement groove is formed in a non-circular shape as viewed in the axial direction or a circular shape in which the center and the axis of the screw shaft do not coincide with each other as viewed from the axial direction. [Effects of the Invention] According to the ball screw type driving device and the movable body floating unit described above, the rotation of the nut member can be restricted, and the vibration transmitted to the screw shaft of the movable body can be absorbed.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. (First Embodiment) Fig. 1 is a plan view showing a ball screw type driving device 1 according to a first embodiment of the present invention. Figure 2 is a cross-sectional view taken along line A-A of Figure 1. As shown in FIGS. 1 and 2, the ball screw type driving device 1 includes a screw shaft 2, a nut member 3, balls 4 (first rolling elements), a movable body 5, a guide portion 6, and a connector 7. As shown in FIG. 2, the screw shaft 2 has a spiral ball rolling groove 21 (rolling element rolling groove) on the outer peripheral surface 2a. Both ends of the screw shaft 2 are rotatably supported via a bearing 9 with respect to the base portion 8 of the ball screw type driving device 1 as shown in Fig. 1 . One end of the screw shaft 2 is connected to the motor 10. The motor 10 is supported by a support member 12 that is fixed to the base portion 8. The motor 10 rotates the screw shaft 2 about its axis C. As shown in FIG. 2, the nut member 3 has a spiral ball load rolling groove 31 (rolling element load rolling groove) on the inner peripheral surface 3b. The ball load rolling groove 31 faces the ball rolling groove 21. When the ball rolling groove 21 faces the ball load rolling groove 31, the ball load rolling path 13 is formed in the opposing portion. The balls 4 are interposed between the ball rolling grooves 21 and the ball load rolling grooves 31. The balls 4 are rolled in the ball load rolling path 13 in a state where a load is applied. The nut member 3 has a rolling element circulation component (not shown) such as a return pipe. The rolling element circulation part has a rolling element circulation path and connects one end of the ball load rolling path 13 to the other end. If one end of the ball load rolling path 13 is connected to the other end, an infinite loop path of the balls 4 is formed. That is, after the ball 4 rolls to the other end (end) of the ball load rolling path 13, it moves in the rolling element circulation component, and is again introduced to one end (starting) of the ball load rolling path 13. As shown in FIG. 1, the movable body 5 is a movable platform in which a bracket 5a is arranged in a rectangular shape in the center. A plurality of screw holes 5a1 are provided in the bracket 5a, and are fixed to the platform portion of the movable body 5 by bolts (not shown). As shown in Fig. 2, a connector 7 to be described later is connected to the bracket 5a. The movable body 5 moves together with the nut member 3 via the connector 7. As shown in FIG. 1, the guide portion 6 supports the movable body 5 so as to be movable in the axial direction (hereinafter referred to as an axial direction) in which the screw shaft 2 extends. The guide portion 6 has a linear guide 61 and a rail 62. The linear guide 61 is provided with a plurality of threaded holes 61a. The linear guide 61 is disposed at four corners of the movable body 5, and is fixed to the movable body 5 by a bolt (not shown) screwed to the screw hole 61a. The rails 62 are disposed on both sides of the screw shaft 2 in plan view and extend in parallel with the screw shaft 2. The linear guide 61 is engaged with the rail 62 via a ball (rolling element) (not shown), and guides the movable body 5 along the rail 62. As shown in FIG. 2, the connector 7 connects the nut member 3 and the movable body 5 in the axial direction via a plurality of balls 71 (second ball rolling elements). The connector 7 has a rolling element arrangement groove 72 in which the balls 71 are disposed in the circumferential direction of the screw shaft 2. The nut member 3 is integrally provided with a plate-shaped flange portion 32. The connector 7 has a pair of plate members 73a and 73b sandwiching the flange portion 32 via the balls 71. The rolling element arrangement groove 72 of the present embodiment is formed by a concave rolling element arrangement surface 33 provided in the flange portion 32 and a concave rolling element arrangement surface 74 provided in the pair of plate members 73a and 73b. At least one of the pair of plate members 73a and 73b (both in the present embodiment) has a mounting hole 75 (mounting portion) that is detachably attached to the movable body 5. The mounting hole 75 penetrates the pair of plate members 73a and 73b in the axial direction. The bracket 5a of the movable body 5 has a screw hole 5a2 at a position opposed to the mounting hole 75. In the threaded hole 5a2, the bolt 76 is screwed. The bolts 76 are disposed to be inserted into the mounting holes 75, and the pair of plate members 73a and 73b are fastened in the axial direction. Thereby, the pair of plate members 73a and 73b are detachably attached to the movable body 5. Next, the configuration of the connector 7 will be described in detail with reference to Figs. 3 to 6 . Fig. 3 is a perspective view of a nut member 3 including a connector 7 according to the first embodiment of the present invention. Fig. 4 is a perspective view showing the removal of the nut member 3 of the plate members 73a and 73b according to the first embodiment of the present invention. Fig. 5 is a view of the rolling element arrangement groove 72 according to the first embodiment of the present invention as seen from the axial direction. Fig. 6 is an enlarged cross-sectional view of an essential part of the connector 7 according to the first embodiment of the present invention. As shown in FIG. 3, the pair of plate members 73a and 73b are formed in a disk shape. An opening 77 through which the screw shaft 2 is inserted is provided at the center of the pair of plate members 73a and 73b. The outer peripheral surface 78A of the pair of plate members 73a and 73b is formed in a circular shape. On the other hand, the inner circumferential surface 78B (opening 77) of the pair of plate members 73a and 73b is formed in an elliptical shape. The pair of plate members 73a and 73b are provided with a cut surface 80 extending in the radial direction (hereinafter referred to as a radial direction) of the screw shaft 2, and each of them is divided into two (see FIG. 4). As shown in FIG. 4, the rolling element arrangement groove 72 includes a first rolling element arrangement groove 72a disposed on one of the axial side faces 32A of the flange portion 32, and a second rolling element arrangement groove 72b disposed in the convex portion. The other side 32B of the axial direction of the edge portion 32. As shown in FIG. 6, the one-side side 32A includes one axial surface 32a of the flange portion 32 and one corner portion 32b of the flange portion 32 in the axial direction. Further, the other surface side 32B includes the other surface 32c in the axial direction of the flange portion 32 and the other corner portion 32d in the axial direction of the flange portion 32. The first rolling element arrangement groove 72a of the present embodiment is disposed at one corner portion 32b of the flange portion 32 in the axial direction. Further, the second rolling element arrangement groove 72b of the present embodiment is disposed at the other corner portion 32d of the flange portion 32 in the axial direction. The flange portion 32 is formed in an elliptical shape as viewed in the axial direction as shown in Fig. 5 . Therefore, the rolling element arrangement groove 72 (the first rolling element arrangement groove 72a and the second rolling element arrangement groove 72b) is formed in an elliptical shape when viewed in the axial direction. Specifically, the rolling element arrangement groove 72 is formed in an elliptical shape whose center coincides with the axis C of the screw shaft 2. Further, the rolling element arrangement groove 72 is formed such that the long axis of the elliptical shape is set along the vertical axis extending in the vertical direction, and the short axis of the elliptical shape is set along the horizontal axis extending in the horizontal direction. The rolling element arrangement groove 72 has a line symmetry shape with respect to the vertical axis, and is also a line symmetrical shape with respect to the horizontal axis. The rolling element arrangement groove 72 of the present embodiment is formed in an elliptical shape having a length of about 1.2 to 1.5 times with respect to the length of the short axis. As shown in FIG. 6, the first rolling element arrangement groove 72a and the second rolling element arrangement groove 72b are in contact with the balls 71 at a specific contact angle with respect to the radial direction of the screw shaft 2. The contact angle between the first rolling element arrangement groove 72a and the second rolling element arrangement groove 72b is set to an oblique angle type of the front surface combination. The contact angle of the bevel type of the front side combination is a contact angle between the line L1 connecting the contact points of the balls 71 and the rolling element arrangement surfaces 33 and 74 in the first rolling element arrangement groove 72a, and the second rolling element arrangement groove. The straight line L2 of the contact point between the connecting ball 71 and the rolling element arrangement faces 33, 74 in 72b gradually approaches the flange portion 32, and the distance between the points of action with respect to the flange portion 32 gradually decreases. When the contact angle between the first rolling element arrangement groove 72a and the second rolling element arrangement groove 72b is α, the following relational expression (1) is satisfied. 45°<α<90° (1) That is, the contact angle α=45° is the same as the critical value of the rigidity (constraint) of the axial direction of the connector 7 and the rigidity (constraint) in the radial direction, and the contact angle α is for improvement. The axial rigidity is preferably greater than 45°. Further, the contact angle α = 90° is not an axial type but a critical value of the thrust type, and the contact angle α is preferably less than 90°. The contact angle α between the first rolling element arrangement groove 72a and the second rolling element arrangement groove 72b is preferably set to have a specific margin with respect to the above-described critical value. For example, it is preferable to satisfy the following relational expression (2). 50°<α<85° (2) In the present embodiment, the contact angle α between the first rolling element arrangement groove 72a and the second rolling element arrangement groove 72b is set to, for example, 60°. Next, the operation of the ball screw type driving device 1 configured as described above and the action of the connector 7 will be described. As shown in FIG. 1, the screw shaft 2 is rotated by the motor 10. When the screw shaft 2 rotates, the nut member 3 that is engaged with the screw shaft 2 via the balls 4 moves in the axial direction. The holder 5a of the movable body 5 is coupled to the nut member 3 via the connector 7. The movable body 5 is guided in the axial direction by the guide portion 6, and moves in the axial direction together with the nut member 3. When the ball screw type driving device 1 is operated, the screw shaft 2, the nut member 3, and the processing accuracy of the balls 4 cause vibration in the radial direction (hereinafter, referred to as vibration when the screw shaft 2 rotates). Figure 6 is schematically represented by the symbol F1). Here, the connector 7 connects the nut member 3 and the movable body 5 in the axial direction via a plurality of balls 71. According to this configuration, the nut member 3 and the movable body 5 can be rigidly coupled in the axial direction, and the vibration at the time of rotation of the screw shaft 2 can be absorbed by the contact point of the balls 71 in the rolling element arrangement groove 72 in the radial direction. In other words, the connector 7 can restrain the movable body 5 in the axial direction to improve the positional accuracy, and the movable body 5 can be placed in a floating state in the radial direction, and the vibration when the screw shaft 2 is rotated can be prevented from being transmitted to the movable body 5. The connector 7 has a rolling element arrangement groove 72 in which a plurality of balls 71 are disposed in the circumferential direction of the screw shaft 2. The rolling element arrangement groove 72 is formed in a non-circular shape (elliptical shape) as viewed in the axial direction as shown in FIG. According to this configuration, the rotation of the nut member 3 can be restricted only by the constraint of the balls 71. In other words, even if the screw shaft 2 rotates, since the rolling element arrangement groove 72 is non-circular, the balls 71 cannot roll in the circumferential direction of the screw shaft 2, and as a result, the nut member 3 does not rotate. Therefore, the rotational torque of the nut member 3 can be received only by the balls 71. Therefore, the rotation of the nut member 3 can be restricted only by the balls 71 without the bolts as in the previous rotation, and the floating function according to the contact variation of the balls 71 can be prevented, and can be absorbed and transmitted to the movable body 5. Vibration when the screw shaft 2 rotates. Further, as shown in FIG. 5, the rolling element arrangement groove 72 has a line symmetry with respect to a vertical axis extending in the vertical direction orthogonal to the axial direction, and a horizontal axis extending in a horizontal direction orthogonal to the axial direction. It is also a line symmetrical shape. According to this configuration, since the contact stress of the plurality of balls 71 is balanced in the vertical direction and the horizontal direction, the anisotropy (deviation) of the restraining force of the balls 71 in the vertical direction and the horizontal direction can be suppressed. Therefore, the deviation of the vibration when the screw shaft 2 is rotated can be suppressed. Further, the rolling element arrangement groove 72 is elliptical as viewed in the axial direction. According to this configuration, the plurality of balls 71 can receive the rotational torque of the nut member 3 as a whole. For example, when the rolling element arrangement groove 72 is formed into a polygonal shape, the load on the rotational torque of the balls 71 disposed at the corner portion of the polygon is increased. However, since there are no corners in the elliptical shape, a plurality of balls 71 can be formed. The rotation torque is roughly equal to the whole. Therefore, the life of the components of the plurality of balls 71 can be extended, and the maintenance frequency or the frequency of replacement can be reduced. Further, in the present embodiment, as shown in FIG. 2, the connector 7 has one of the flange portions 32 sandwiched by the plurality of balls 71 disposed in the first rolling element arrangement groove 72a and the second rolling element arrangement groove 72b. The plate members 73a and 73b and the pair of plate members 73a and 73b have attachment holes 75 detachably attached to the movable body 5. According to this configuration, the flange portion 32 can be sandwiched by the plurality of balls 71 disposed in the first rolling element arrangement groove 72a and the second rolling element arrangement groove 72b, and can be connected to the movable body 5. In other words, since the pair of plate members 73a and 73b can realize the structure in which only the balls 71 are in contact with the flange portion 32 (nut member 3), the floating function of the contact change by the balls 71 is not impaired, and absorption can be absorbed. Vibration when the screw shaft 2 rotates. Further, as shown in FIG. 6, each of the first rolling element arrangement groove 72a and the second rolling element arrangement groove 72b is in contact with the balls 71 at a specific contact angle with respect to the radial direction of the screw shaft 2. The contact angle between the first rolling element arrangement groove 72a and the second rolling element arrangement groove 72b is set to a bevel type of the front combination. According to this configuration, the pitch of the nut member 3 can be absorbed (shown schematically in FIG. 6 by the symbol F2). In other words, since the bevel type of the front side combination has a small distance between the points of action with respect to the flange portion 32, the ball 71 can be changed by the contact point, and the angle of the direction between the nut members 3 can be changed. Therefore, the vibration caused by the pitching of the nut member 3 may not be transmitted to the movable body 5. Further, the contact angle α between the first rolling element arrangement groove 72a and the second rolling element arrangement groove 72b satisfies the relationship of 45° < α < 90°. That is, when the contact angle α is larger than 45°, the rigidity of the axial direction of the connector 7 is higher than the rigidity in the radial direction, and the nut member 3 and the movable body 5 can be rigidly coupled in the axial direction, and the movement of the movable body 5 in the axial direction can be improved. Precision. Further, when the contact angle α is less than 90°, the connector 7 can be formed into a bevel type as described above, and the vibration in the radial direction (indicated by the symbol F1) in addition to the rotation of the screw shaft 2 can also absorb the nut. The vibration caused by the pitching of the member 3 (shown by the symbol F2). As described above, the ball screw type driving device 1 includes the screw shaft 2 having the spiral ball rolling groove 21 on the outer peripheral surface 2a, and the nut member 3 having the ball rolling groove 21 on the inner peripheral surface 3b. a spiral ball bearing rolling groove 31; a plurality of balls 4 interposed between the ball rolling groove 21 and the ball load rolling groove 31; the movable body 5 movable together with the nut member 3; and guiding The portion 6 supports the movable body 5 so as to be movable in the axial direction in which the screw shaft 2 extends. The ball screw type driving device 1 has a connector 7 that couples the nut member 3 and the movable body 5 via a plurality of balls 71 in the axial direction. The connector 7 has a rolling element arrangement groove 72 in which a plurality of balls 71 are disposed in the circumferential direction of the screw shaft 2. The rolling element arrangement groove 72 is formed to be non-circular (elliptical) when viewed in the axial direction. According to this configuration, the rotation of the nut member 3 can be restricted, and the vibration transmitted to the screw shaft of the movable body 5 can be absorbed. (Second embodiment) Next, a second embodiment of the present invention will be described. In the following description, the same or equivalent components as those of the above-described embodiments are denoted by the same or equivalent reference numerals, and the description thereof will be omitted or omitted. Fig. 7 is a cross-sectional view showing a ball screw type driving device 1A according to a second embodiment of the present invention. Fig. 8 is a view of the rolling element arrangement groove 72A according to the second embodiment of the present invention as seen from the axial direction. As shown in Fig. 7, the ball screw type driving device 1A of the second embodiment differs from the above-described embodiment in that it has a movable body floating unit 100 that is detachably attached. The movable body floating unit 100 has a connector 7 that couples the nut member 3 and the movable body 5 via a plurality of balls 71 in the axial direction. The connector 7 of the second embodiment has a mounting plate 101 that is detachably attached to the movable body 5, and a pair of plate members 102a and 102b that sandwich the mounting plate 101 via a plurality of balls 71. The rolling element arrangement groove 72A in which the plurality of balls 71 are disposed is formed by the concave rolling element arrangement surface 103 provided on the mounting plate 101 and the concave rolling element arrangement surface 104 provided on the pair of plate members 102a and 102b. . The mounting plate 101 has a mounting hole 105 that penetrates in the axial direction. A bore 105a is formed in the mounting hole 105. The bolts 76 screwed into the screw holes 5a2 of the bracket 5a of the movable body 5 are inserted into the mounting holes 105. The mounting plate 101 is detachably attached to the movable body 5 by bolts 76. Further, the mounting plate 101 has a through hole 106 that penetrates in the axial direction. The bolts 107 that connect the pair of plate members 102a and 102b are inserted into the through holes 106. The plate member 102a has a through hole 108 penetrating in the axial direction at a position facing the through hole 106. A through hole 108a is formed in the through hole 108. The plate member 102b has a screw hole 109 at a position opposed to the through hole 106. A bolt 107 is screwed into the threaded hole 109. The bolts 107 are disposed to be inserted through the through holes 106 and 108, and the pair of plate members 102a and 102b are fastened in the axial direction. Thereby, the pair of plate members 102a and 102b are connected. Further, the through hole 106 is formed to be larger than the diameter of the bolt 107, and is configured such that the bolt 107 does not contact the mounting plate 101. At least one of the pair of plate members 102a and 102b (the plate member 102a in the present embodiment) has a screw hole 109 (mounting portion) that is detachably attached to the nut member 3. A bolt 110 is screwed into the threaded hole 109. The flange portion 32 of the nut member 3 is provided with an insertion hole 111 through which the bolt 110 is inserted. A through hole 111a is formed in the insertion hole 111. The bolt 110 fastens the plate member 102a and the flange portion 32 in the axial direction. Thereby, the plate member 102a is detachably attached to the nut member 3. The rolling element arrangement groove 72A includes a first rolling element arrangement groove 72a disposed on one surface 101a of the mounting plate 101 in the axial direction, and a second rolling element arrangement groove 72b disposed on the other surface 101b of the mounting plate 101 in the axial direction. . The first rolling element arrangement groove 72a and the second rolling element arrangement groove 72b are not of the above-described bevel type, and the plurality of balls 71 are arranged in a thrust type. As shown in FIG. 8, the rolling element arrangement groove 72A (the first rolling element arrangement groove 72a and the second rolling element arrangement groove 72b) is formed in a polygonal shape as viewed in the axial direction. Specifically, the rolling element arrangement groove 72A is formed in a quadrangular shape in which the position of the center of gravity coincides with the axis C of the screw shaft 2 . Further, the rolling element arrangement groove 72A is formed such that a short side is set along a vertical axis extending in the vertical direction, and a rectangular shape of a long side is set along a horizontal axis extending in the horizontal direction. The rolling element arrangement groove 72A is formed in a rectangular shape having a length of about 1.2 to 1.5 times with respect to the length of the short side. The corner 72A1, which is the intersection of the short side and the long side of the rectangle, is attached with a specific curvature to be bent. According to the movable body floating unit 100 having the above configuration, as in the above-described embodiment, the vibration transmitted to the screw shaft 2 of the movable body 5 can be absorbed. In other words, as shown in FIG. 7, the connector 7 connects the nut member 3 and the movable body 5 via a plurality of balls 71 in the axial direction. According to this configuration, the nut member 3 and the movable body 5 can be rigidly coupled in the axial direction, and the vibration at the time of rotation of the screw shaft 2 can be absorbed by the contact point of the balls 71 in the rolling element arrangement groove 72 in the radial direction. Further, as shown in FIG. 8, since the rolling element arrangement groove 72A is non-circular (quadrilateral), the ball 71 cannot be rolled in the circumferential direction of the screw shaft 2, and the rotation of the nut member 3 can be restricted only by the constraint of the balls 71. Therefore, the floating function according to the contact change of the balls 71 is not impaired, and the vibration transmitted to the screw shaft 2 of the movable body 5 can be absorbed. Further, in the second embodiment, as shown in Fig. 7, the connector 7 has a mounting plate 101 that is detachably attached to the movable body 5, and a pair of plate members 102a and 102b that are disposed via the first The plurality of balls 71 of the rolling element arrangement groove 72a and the second rolling element arrangement groove 72b sandwich the mounting plate 101; and the plate member 102a has a screw hole 109 that is detachably attached to the nut member 3. According to this configuration, the mounting plate 101 can be sandwiched by the plurality of balls 71 disposed in the first rolling element arrangement groove 72a and the second rolling element arrangement groove 72b, and the nut member 3 and the movable body 5 can be detachably coupled. Therefore, the arrangement of the movable body floating unit 100 can be easily performed with respect to the conventional ball screw type driving device. Further, the rolling element arrangement groove 72A of the second embodiment is disposed on one surface 101a and the other surface 101b of the mounting plate 101 in the axial direction. According to this configuration, the processing of the rolling element arrangement groove 72A becomes easy. In other words, when the rolling element arrangement groove 72 is disposed in the corner portions 32b and 32d (see FIG. 6) of the flange portion 32 as in the above-described embodiment, it is necessary to form a groove by a cam grinding machine or the like. However, the second embodiment is as follows. In the case where the rolling element arrangement groove 72A is formed with respect to the plate surface of the mounting plate 101, since it can be formed by a general processing machine such as a ball end mill, a quadrangular groove as shown in Fig. 8 can be easily formed. According to the second embodiment, the movable body floating unit 100 provided in the ball screw type driving device 1A includes a screw shaft 2 having a spiral ball rolling groove 21 on the outer peripheral surface 2a, and a nut member 3 therein. The circumferential surface 3b has a ball-shaped rolling groove 31 that is spirally opposed to the ball rolling groove 21; a plurality of balls 4 interposed between the ball rolling groove 21 and the ball load rolling groove 31; and the movable body 5, which can The nut member 3 is moved together; and the guide portion 6 supports the movable body 5 so as to be movable in the axial direction in which the screw shaft 2 extends. The movable body floating unit 100 has a connector 7 that couples the nut member 3 and the movable body 5 via a plurality of balls 71 in the axial direction. The connector 7 has a rolling element arrangement groove 72A in which a plurality of balls 71 are disposed in the circumferential direction of the screw shaft 2. The rolling element arrangement groove 72A is formed to be non-circular (quadrilateral) as viewed in the axial direction. According to this configuration, the rotation of the nut member 3 can be restricted, and the vibration transmitted to the screw shaft of the movable body 5 can be absorbed. Hereinabove, the preferred embodiments of the present invention have been described with reference to the drawings, but the present invention is not limited to the above embodiments. The shapes, combinations, and the like of the respective constituent members shown in the above-described embodiments are merely examples, and various modifications can be made based on design requirements and the like without departing from the scope of the present invention. Fig. 9 is a view showing the rolling element arrangement groove 72B according to another embodiment of the present invention as seen from the axial direction. The rolling element arrangement groove 72B shown in FIG. 9 includes a first rolling element arrangement groove 72a and a second rolling element arrangement groove 72b having the same shape (wave shape) repeated in the circumferential direction of the screw shaft 2 by a specific number of cycles. The period of the first rolling element arrangement groove 72a and the period of the second rolling element arrangement groove 72b are shifted from each other by a half cycle. According to this configuration, the structure of the above-described embodiment (see FIGS. 5 and 8 ) that coincides with the period of the first rolling element arrangement groove 72 a and the period of the second rolling element arrangement groove 72 b can greatly reduce the number of balls. The anisotropy (deviation) caused by the binding force of 71. Fig. 10 is a view showing the rolling element arrangement groove 72C according to another embodiment of the present invention as seen from the axial direction. The rolling element arrangement groove 72C shown in Fig. 10 is formed in a circular shape when viewed in the axial direction, but the center C1 of the circle does not coincide with the axis C of the screw shaft 2. As described above, when the center C1 of the rolling element arrangement groove 72C is offset from the axis C of the screw shaft 2, even if it is circular, the balls 71 cannot roll in the circumferential direction of the screw shaft 2. Therefore, as in the above embodiment, the rotation of the nut member 3 can be restricted only by the constraint of the balls 71. Further, for example, in the above-described embodiment, the rolling element arrangement groove is one line, but the rolling element arrangement groove may be a plurality of rows, and the diameter of the second rolling element may be reduced (preferably smaller than the first one). Rolling body). When the number of the second rolling elements increases and the diameter of the second rolling elements decreases, the contact stress of Hertz increases, and the rotation of the nut member 3 can be preferably restricted. In the above-described embodiment, the ball is exemplified as the second rolling element. However, as the second rolling system, the contact point may be changed. For example, a spherical roller having a thicker center and a thinner center may be used. Further, for example, in the first embodiment, the rolling element arrangement groove is disposed in a bevel type, but may be arranged in a thrust type as in the second embodiment. In this case, the rolling element arrangement groove is disposed on one of the axial direction and the other surface of the flange portion. Further, the shape of the rolling element arrangement groove of the first embodiment may be a polygon (a quadrangle or another polygon) as shown in Fig. 8, and may be shaped as shown in Fig. 9, or as shown in Fig. 10. It is generally circular and offsets the center. Further, for example, in the second embodiment, the rolling element arrangement grooves are arranged in a thrust type, but they may be arranged in a bevel type as in the second embodiment. For example, the shape and arrangement of the grooves can be changed as in the case of the prior art, that is, the second embodiment can change the contact angle as in the first embodiment. Moreover, the shape of the rolling element arrangement groove of the second embodiment can be elliptical as shown in FIG. 5, and can be a polygon other than the quadrilateral shown in FIG. 8, and can be shaped as shown in FIG. It may also be circular as shown in FIG. 10 and offset in the center. [Industrial Applicability] According to the above-described ball screw type driving device and the movable body floating unit, the rotation of the nut member can be restricted, and the vibration transmitted to the screw shaft of the movable body can be absorbed.

1‧‧‧Ball screw drive
1A‧‧‧Ball screw drive
2‧‧‧Screw shaft
2a‧‧‧outer surface
3‧‧‧ nut components
3b‧‧‧ inner circumference
4‧‧‧Roads (1st rolling element)
5‧‧‧ movable body
5a‧‧‧ bracket
5a1‧‧‧Threaded holes
5a2‧‧‧Threaded holes
6‧‧‧Guidance Department
7‧‧‧Connector
8‧‧‧Base Department
9‧‧‧ bearing
10‧‧‧ motor
12‧‧‧Support components
13‧‧‧Ball load rolling path
21‧‧‧Roll rolling groove (rolling element rolling groove)
31‧‧‧Ball load rolling groove (rolling element load rolling groove)
32‧‧‧Flange
32A‧‧‧One side
32a‧‧‧ side
32B‧‧‧The other side
32b‧‧‧ corner
32c‧‧‧The other side
32d‧‧‧Other corner
33‧‧‧Roller body configuration surface
61‧‧‧Linear guide
61a‧‧‧Threaded holes
62‧‧‧ Track
71‧‧‧ balls (second rolling element)
72‧‧‧Roller body configuration slot
72A‧‧‧ rolling element configuration slot
72A1‧‧‧ corner
72a‧‧‧1st rolling element configuration slot
72B‧‧‧ rolling element configuration slot
72b‧‧‧2nd rolling element configuration slot
72C‧‧‧ rolling element configuration slot
73a‧‧‧A pair of plate members
73b‧‧‧A pair of plate members
74‧‧‧Roller body configuration surface
75‧‧‧Mounting hole (mounting part)
76‧‧‧Bolts
77‧‧‧ openings
78A‧‧‧ outer perimeter
78B‧‧‧ inner circumference
80‧‧‧ cut face
100‧‧‧ movable body floating unit
101‧‧‧Installation board
101a‧‧‧ side
101b‧‧‧The other side
102a‧‧‧A pair of plate members
102b‧‧‧A pair of plate members
103‧‧‧ rolling element configuration surface
104‧‧‧Roller body configuration surface
105‧‧‧Mounting hole (mounting part)
105a‧‧‧镗孔
106‧‧‧through holes
107‧‧‧Bolts
108‧‧‧through holes
108a‧‧‧镗孔
109‧‧‧Threaded holes
110‧‧‧ bolt
111‧‧‧ inserted through hole
111a‧‧‧镗孔
AA‧‧‧arrow
C‧‧‧Axis
C1‧‧ Center
F1‧‧ symbol
F2‧‧‧ symbol
L1‧‧‧ Straight line
L2‧‧‧ Straight line α‧‧‧ contact angle

Fig. 1 is a plan view showing a ball screw type driving device according to a first embodiment of the present invention. Figure 2 is a cross-sectional view taken along line A-A of Figure 1 of the present invention. Fig. 3 is a perspective view of a nut member including a coupler according to the first embodiment of the present invention. Fig. 4 is a perspective view showing the removal of the nut member 3 of the plate member according to the first embodiment of the present invention. Fig. 5 is a view showing the rolling element arrangement groove of the first embodiment of the present invention as seen from the axial direction. Fig. 6 is an enlarged cross-sectional view of an essential part of a connector according to a first embodiment of the present invention. Fig. 7 is a cross-sectional view showing a ball screw type driving device according to a second embodiment of the present invention. Fig. 8 is a view showing the rolling element arrangement groove of the second embodiment of the present invention as seen from the axial direction. Fig. 9 is a view showing a rolling element arrangement groove according to another embodiment of the present invention as seen from the axial direction. Fig. 10 is a view showing a rolling element arrangement groove according to another embodiment of the present invention as seen from the axial direction.

2‧‧‧Screw shaft

3‧‧‧ nut components

7‧‧‧Connector

32‧‧‧Flange

33‧‧‧Roller body configuration surface

71‧‧‧ balls (second rolling element)

72‧‧‧Roller body configuration slot

72a‧‧‧1st rolling element configuration slot

72b‧‧‧2nd rolling element configuration slot

73a‧‧‧A pair of plate members

73b‧‧‧A pair of plate members

75‧‧‧Mounting hole (mounting part)

77‧‧‧ openings

C‧‧‧Axis

Claims (6)

A ball screw type driving device comprising: a screw shaft having a spiral rolling element rolling groove on an outer circumferential surface; and a nut member having a spiral rolling body load on the inner circumferential surface opposite to the rolling element rolling groove a rolling groove; a plurality of first rolling elements interposed between the rolling element rolling groove and the rolling element load rolling groove; a movable body movable together with the nut member; and a guiding portion available for the screw shaft The extending body axially supports the movable body; and the connector that connects the nut member and the movable body via a plurality of second rolling elements in the axial direction; and the connector has a rolling element arrangement groove. The plurality of second rolling elements are disposed in a circumferential direction of the screw shaft; the rolling element arrangement groove is formed in a non-circular shape as viewed in the axial direction, or is formed in a center from the axial direction and does not coincide with an axis of the screw shaft Round shape. The ball screw type drive device according to claim 1, wherein the nut member is integrally provided with a plate-shaped flange portion, and the rolling element arrangement groove includes: a first rolling element arrangement groove disposed on the flange portion One of the axial direction side faces; and the second rolling element arrangement groove disposed on the other side of the axial direction of the flange portion; and the connector has a pair of plate members that are disposed on the first rolling element Arranging the plurality of second rolling elements of the groove and the second rolling element arrangement groove to sandwich the flange portion; and at least one of the pair of plate members has a mounting portion that is detachably attached to the movable body . The ball screw type drive device according to claim 1, wherein the connector has a mounting plate that is detachably attached to the movable body, and the rolling element arrangement groove includes a first rolling element arrangement groove that is disposed in the mounting plate. One of the axial direction surfaces; and the second rolling element arrangement groove disposed on the other surface of the mounting plate in the axial direction; and the connector has a pair of plate members that are disposed in the first rolling element arrangement groove And the plurality of second rolling elements of the second rolling element arrangement groove sandwich the mounting plate; and at least one of the pair of plate members has a mounting portion that is detachably attached to the nut member. The ball screw type driving device according to claim 2 or 3, wherein each of the first rolling element arrangement groove and the second rolling element arrangement groove has a specific contact angle with respect to a radial direction of the screw shaft and the second The rolling element is in contact with each other; and the contact angle between the first rolling element arrangement groove and the second rolling element arrangement groove is set to a bevel type of the front surface combination. The ball screw type driving device according to claim 4, wherein a contact angle α between the first rolling element arrangement groove and the second rolling element arrangement groove satisfies a relationship of 45° < α < 90°. A movable body floating unit provided in a ball screw type driving device, comprising: a screw shaft having a spiral rolling element rolling groove on an outer peripheral surface; and a nut member having a rolling body with the rolling element on an inner circumferential surface a rolling element load rolling groove having a spiral direction opposite to the groove; a plurality of first rolling elements interposed between the rolling element rolling groove and the rolling element load rolling groove; and a movable body movable together with the nut member a guide portion that supports the movable body in an axial direction in which the screw shaft extends, and a connector that connects the nut member and the movable body via a plurality of second rolling elements in the axial direction; The connector has a rolling element arrangement groove in which the plurality of second rolling elements are arranged in the circumferential direction of the screw shaft, and the rolling element arrangement groove is formed in a non-circular shape as viewed from the axial direction or formed from the axial direction. It is a circle that is inconsistent with the axis of the screw shaft described above.