JP2023003335A - Nut device spacer - Google Patents

Abstract

To provide a nut device spacer capable of regulating rotations in a holder.SOLUTION: Nut device spacers are interposed between a plurality of nut portions disposed in a cylindrical holder. On one of an inner peripheral surface of the holder and an outer peripheral surface of the nut portion, a projecting portion projecting out in a diametrical direction is provided. On the other of the inner peripheral surface of the holder and the outer peripheral surface of the nut portion, a recessed portion is provided, which depresses in the diametrical direction and is fitted with the projecting portion. The nut device spacer is provided with an annular spacer body, and a spacer recessed portion or a spacer projecting portion corresponding to the projecting portion or the recessed portion provided on the inner peripheral surface of the holder, on an outer peripheral surface of the spacer.SELECTED DRAWING: Figure 7

Description

The present invention relates to a nut device spacer.

A ball screw device is a device that efficiently converts rotary motion into linear motion or linear motion into rotary motion. The nut of the ball screw device disclosed in the following patent document is a nut device composed of a plurality of parts. This nut device includes a plurality of nut portions, a cylindrical holder, and a nut device spacer (hereinafter sometimes simply referred to as a "spacer") arranged between the nuts. The nut portion has an annular shape. Further, the inner peripheral surface of the nut portion is provided with an inner peripheral raceway surface of one turn and a circulation portion that connects the start point and the end point of the inner peripheral raceway surface. The plurality of nut portions and the plurality of spacers are arranged inside the holder while being alternately arranged in the axial direction along which the screw shaft extends. A nut fixing component is fixed to the end surface of the holder, and the nut portion and the spacer do not drop out of the inside of the holder.

JP 2016-142376 A JP 2009-35216 A

In the above nut device, the phase of the spacer is not positioned with respect to the holder. Therefore, the spacer may rotate inside the holder, causing noise and vibration.

The present disclosure has been made in view of the above problems, and an object of the present disclosure is to provide a nut device spacer capable of restricting rotation.

In order to achieve the above object, a nut device spacer according to a first aspect of the present disclosure is a nut device spacer interposed between a plurality of nut portions arranged in a cylindrical holder. One of the inner peripheral surface of the holder and the outer peripheral surface of the nut portion is provided with a convex portion protruding in the radial direction. The other of the inner peripheral surface of the holder and the outer peripheral surface of the nut portion is provided with a concave portion which is recessed in the radial direction and into which the convex portion is fitted. The nut device spacer includes an annular spacer main body, and an outer peripheral surface of the spacer provided with a spacer concave portion or an interval corresponding to the convex portion or the concave portion provided on the inner peripheral surface of the holder. A seat projection is provided.

The nut device spacer is fixed to the holder so that the spacer concave portion (or spacer convex portion) fits into the convex portion (or concave portion) of the holder so as not to rotate. Therefore, the generation of noise and vibration is suppressed. Moreover, since the projection (or recess) for fixing the nut portion is used, no special processing or the like is required for the holder. Therefore, manufacturing of the nut device is facilitated.

A nut device according to a second aspect of the present disclosure is a nut device spacer interposed between a plurality of nut portions arranged in a cylindrical holder. The nut portion has an annular nut body and a nut holding hole that axially penetrates the nut body and into which a rod member is inserted. The nut device spacer has an annular spacer main body and a spacer holding hole that passes through the spacer main body in the axial direction and into which the rod member is inserted. A plurality of the spacer holding holes are provided while being separated from each other in the circumferential direction.

The nut member and the nut device spacer are connected by a rod member. Therefore, if at least one of the plurality of nut members can be fixed to the holder, the spacer will not rotate within the holder, thereby suppressing noise and vibration. Further, a plurality of spacer holding holes of the spacer are provided in the circumferential direction. Therefore, the second rod-like members for connecting with the nut portions arranged on both sides in the axial direction of the spacer are fitted in different spacer holding holes. As a result, the S groove of the nut portion arranged on one side in the axial direction with respect to the spacer and the S groove of the nut portion arranged on the other side in the axial direction are arranged in different directions when viewed from the center of the screw shaft. can. From the above, the phase of the nut portion can be managed.

As a desirable aspect of the spacer for a nut device of the first aspect and the second aspect, it has an S-groove recess formed by recessing a part of the spacer main body in the axial direction. The S-groove concave portion overlaps with the S-groove provided in the nut portion when viewed from the axial direction.

Within the holder, the nut portion receives an axial load from an axially arranged nut device spacer. On the other hand, when the ball rolls in the S groove of the nut portion, it is separated from the outer circumference raceway surface of the screw shaft. That is, the portion of the nut body that overlaps the S groove is not supported by the screw shaft via the balls, and has low support rigidity. Therefore, there is a possibility of deformation when a high load acts. According to the above configuration, the portion of the nut body provided with the S-groove overlaps with the S-groove concave portion of the spacer, so that it does not receive an axial load from the spacer. Therefore, deformation of the nut body can be suppressed.

The nut device spacer of the present disclosure is restricted from rotating within the holder.

FIG. 1 is an axial cross-sectional view of the ball screw device of Embodiment 1. FIG. 2 is a perspective view of the holder of Embodiment 1. FIG. FIG. 3 is a perspective view of the nut portion of Embodiment 1. FIG. 4 is a sectional view taken along line IV-IV in FIG. 1. FIG. 5 is a cross-sectional view taken along line VV of FIG. 1. FIG. 6 is a sectional view taken along the line VI-VI of FIG. 1. FIG. 7 is a perspective view of the spacer of Embodiment 1. FIG. 8 is a cross-sectional view taken along line VIII-VIII of FIG. 1. FIG. 9 is a cross-sectional view of a holder and a nut portion in a nut device according to Modification 1. FIG. 10 is a cross-sectional view of a holder and a spacer in a nut device according to Modification 1. FIG. FIG. 11 is a perspective view of a holder of modification 2. FIG. FIG. 12 is a cross-sectional view of a nut device having three nut portions in Modification 2, cut so as to overlap the first nut portion. FIG. 13 is a cross-sectional view of a nut device having three nut portions in Modification 2, cut so as to overlap with the second nut portion. FIG. 14 is a cross-sectional view of a nut device having three nut portions in Modification 2, cut so as to overlap with the third nut portion. FIG. 15 is a cross-sectional view of a nut device having two nut portions in Modification 2, cut so as to overlap the first nut portion. FIG. 16 is a cross-sectional view of a nut device having two nut portions in Modification 2, cut so as to overlap the second nut portion. FIG. 17 is a cross-sectional view of a nut device having four nut portions in Modification 2, cut so as to overlap the first nut portion. FIG. 18 is a cross-sectional view of a nut device having four nut portions in Modification 2, cut so as to overlap the second nut portion. FIG. 19 is a cross-sectional view of a nut device having four nut portions in Modification 2, cut so as to overlap the third nut portion. FIG. 20 is a cross-sectional view of a nut device having four nut portions in Modification 2, cut so as to overlap the fourth nut portion. FIG. 21 is an axial cross-sectional view of the ball screw device of Embodiment 2. FIG. 22 is a side view of the holder of Embodiment 2 as seen from the first direction. FIG. FIG. 23 is an exploded perspective view of a nut portion, a spacer, and a rod-shaped member according to Embodiment 2; FIG. 24 is an exploded perspective view of the nut portion, the spacer, and the rod-shaped member of Modification 3. FIG. 25 is a perspective view of a spacer according to Modification 4. FIG. 26 is a side view of a spacer according to Modification 4. FIG. FIG. 27 is an axial cross-sectional view of the ball screw device of Embodiment 3. FIG. 28 is a side view of the holder of Embodiment 3 as viewed from the first direction. FIG. 29 is an exploded perspective view of a nut portion, a spacer, and a rod-shaped member according to Embodiment 3. FIG.

Hereinafter, the present disclosure will be described in detail with reference to the drawings. The present disclosure is not limited by the following modes for carrying out the invention (hereinafter referred to as embodiments). In addition, components in the following embodiments include those that can be easily assumed by those skilled in the art, those that are substantially the same, and those that fall within a so-called equivalent range. Furthermore, the constituent elements disclosed in the following embodiments can be combined as appropriate.

(Embodiment 1)
FIG. 1 is an axial cross-sectional view of the ball screw device of Embodiment 1. FIG. 2 is a perspective view of the holder of Embodiment 1. FIG. FIG. 3 is a perspective view of the nut portion of Embodiment 1. FIG. 4 is a sectional view taken along line IV-IV in FIG. 1. FIG. 5 is a cross-sectional view taken along line VV of FIG. 1. FIG. 6 is a sectional view taken along the line VI-VI of FIG. 1. FIG. 7 is a perspective view of the spacer of Embodiment 1. FIG. 8 is a cross-sectional view taken along line VIII-VIII of FIG. 1. FIG.

As shown in FIG. 1 , a ball screw device 100 according to Embodiment 1 includes a nut device 101 , a screw shaft 102 having an outer peripheral raceway surface 102 a provided on its outer peripheral surface, and a plurality of balls 103 . In the following description, the direction parallel to the screw shaft 102 is called the axial direction.

In the ball screw device 100 of this embodiment, the nut device 101 is rotatably fixed to a housing (not shown). Rotational motion generated by a motor (not shown) is transmitted to the nut device 101 , and the nut device 101 rotates around the central axis O of the screw shaft 102 . As a result, the one end 102b of the screw shaft 102 moves in the first direction X1 or the second direction X2 pointed by the other end 102c of the screw shaft 102. It should be noted that the method of using the ball screw device 100 described above is just an example, and the screw shaft 102 is used so that the rotational motion from the motor is transmitted and the nut device 101 moves in the first direction X1 or the second direction X2. good too. Alternatively, it may be used to convert linear motion to rotary motion.

As shown in FIG. 1, the nut device 101 includes a holder 1, a plurality of nut portions 2 accommodated inside the holder 1, a plurality of spacers 3 disposed between the nut portions 2, and Lid portions 4 and 5 are provided to prevent the nut portion 2 and the spacer 3 from coming off.

As shown in FIG. 2 , the holder 1 includes a cylindrical holder body 10 and projections 11 . The inner peripheral surface 12 and the outer peripheral surface 13 of the holder body 10 are circular when viewed from the axial direction. That is, the holder body 10 has a cylindrical shape. The convex portion 11 is a protrusion provided on the inner peripheral surface 12 of the holder body 10 and extends in the axial direction. The convex portion 11 has a quadrangular shape when viewed from the axial direction. Therefore, the convex portion 11 has a pair of side surfaces 11a, 11a facing in the circumferential direction. The axial length of the convex portion 11 is shorter than the axial length of the holder body 10 . Therefore, the end portion of the inner peripheral surface 12 of the holder main body 10 in the first direction X1 is a circular first fitting portion 14 in which the convex portion 11 is not provided. In addition, the end portion of the inner peripheral surface 12 of the holder main body 10 in the second direction X2 is a circular second fitting portion 15 in which the convex portion 11 is not provided.

As shown in FIG. 1, in the embodiment, three nut portions 2 are provided. Hereinafter, they are referred to as a first nut portion 2A, a second nut portion 2B, and a third nut portion 2C in order from the first direction X1 to the second direction X2. Next, the details of the first nut portion 2A, the second nut portion 2B, and the third nut portion 2C will be described. be. Therefore, the first nut portion 2A is taken as a representative example, and the description of the second nut portion 2B and the third nut portion 2C is omitted.

As shown in FIG. 3 , the nut portion 2 includes an annular nut body 20 , an inner raceway surface 21 , an S groove 22 and a recess 23 . The nut body 20 has circular inner and outer peripheral surfaces when viewed from the axial direction. The inner raceway surface 21 is a spiral groove facing the outer raceway surface 102 a of the screw shaft 102 . A track on which the balls 103 roll is formed between the inner raceway surface 21 and the outer raceway surface 102a. In addition, the inner circumference raceway surface 21 is for one turn. The S groove 22 is a circulation part that returns the balls 103 that have reached the end point of the inner raceway surface 21 to the starting point of the inner raceway surface 21 . In addition, according to the S groove 22, the thickness of the nut body 20 in the axial direction can be made thinner than when the top type is adopted. Further, the outer peripheral surface of the nut body 20 can be polished, so that the nut body 20 can be fitted to the holder 1 with high accuracy. The recess 23 is a space formed by recessing a portion of the outer peripheral surface of the nut body 20 radially inward.

The concave portion 23 has a rectangular shape when viewed from the axial direction, and has the same cross-sectional shape as the convex portion 11 . A pair of side surfaces 23a, 23a extending in the radial direction are provided on both sides of the recess 23 in the circumferential direction. Three recesses 23 in this embodiment are provided corresponding to the number of nut portions 2 . The three recesses 23 are arranged at intervals of 120°. Therefore, the three recesses 23 are arranged so as to be spaced apart from each other in the circumferential direction.

One recess 23 of the three recesses 23 is arranged at a point-symmetrical position with respect to the S groove 22 about the central axis O, that is, at a position rotated 180° from the S groove 22 . Therefore, the S grooves 22 are arranged so as not to overlap each of the recesses 23 when viewed from the central axis O (in different phases). If the S groove 22 and the recessed portion 23 are in the same phase, the thickness between the S groove 22 and the recessed portion 23 becomes small, and the strength may be extremely weakened. Therefore, the nut portion 2 of this embodiment has sufficient strength.

Hereinafter, among the three recesses 23, the recess 23 that is 180 degrees out of phase with the S groove is referred to as a first recess 23A. When the nut portion 2 is viewed from the first direction X1, the nut portion 2 is called a second recess portion 23B and a third recess portion 23C in the order of arrangement in the counterclockwise direction (see arrow A in FIG. 2) from the first recess portion 23A.

Next, the relationship between each nut portion 2 and the holder 1 will be described with reference to FIGS. 4 to 6. FIG. In addition, in order to clarify the direction in which the S groove 22 is arranged in each nut portion 2 as viewed from the central axis O, a dot is attached to the region overlapping the S groove 22 .

As shown in FIGS. 4 to 6 , the convex portion 11 of the holder 1 is fitted into the concave portion 23 of each nut portion 2 . A pair of side surfaces 23a, 23a of each recess 23 are in contact with a pair of side surfaces 11a, 11a of the projection 11. As shown in FIG. Therefore, each nut portion 2 is fixed to the holder 1 so as not to rotate.

Also, the recesses 23 of the respective nut portions 2 into which the projections 11 are fitted are different. Specifically, as shown in FIG. 4, the projection 11 of the holder 1 is fitted into the second recess 23B of the first nut portion 2A. As shown in FIG. 5, the convex portion 11 of the holder 1 is fitted into the first concave portion 23A of the second nut portion 2B. As shown in FIG. 6, the projection 11 of the holder 1 is fitted into the third recess 23C of the third nut portion 2C. Therefore, each of the first nut portion 2A, the second nut portion 2B, and the third nut portion 2C has a different concave portion 23 into which the convex portion 11 is fitted. Therefore, the S grooves 22 of each nut portion 2 are arranged at intervals of 120°, and are in different directions when viewed from the central axis O. As shown in FIG.

As shown in FIG. 1 , the spacer 3 is arranged between the nut portions 2 and is for adjusting the axial position of the nut portion 2 . The spacer 3 may be made of an elastic material or the thickness of the spacer 3 may be adjusted so that each nut portion 2 may be preloaded, and there is no particular limitation in the present disclosure. As shown in FIG. 7 , the spacer 3 includes an annular spacer main body 30 and one spacer recess 31 . The spacer main body 30 has a flat plate shape. In the present disclosure, the shape of the spacer main body 30 is not particularly limited, and may be conical, such as a so-called disc spring. The spacer recess 31 is a space formed by recessing the outer peripheral portion of the spacer main body 30 . The spacer concave portion 31 has the same shape as the convex portion 11 when viewed from the axial direction, and has a square shape. A pair of side surfaces 31a, 31a extending in the radial direction are provided on both sides of the spacer recess 31 in the circumferential direction. As shown in FIG. 8 , the protrusion 11 of the holder 1 is fitted in the spacer recess 31 . A pair of side surfaces 31a, 31a of the spacer recess 31 are in contact with a pair of side surfaces 11a, 11a of the projection 11. As shown in FIG. Therefore, each spacer 3 is non-rotatably fixed to the holder 1 .

As shown in FIG. 1, the lids 4 and 5 are disk-shaped parts. The outer diameters of the lids 4 and 5 are slightly larger than the inner diameter of the holder body 10 . The lid portions 4 and 5 are press-fitted into the first fitting portion 14 and the second fitting portion 15 of the holder main body 10 and integrated with the holder 1 .

As described above, the spacer 3 of the first embodiment is a nut device spacer interposed between the plurality of nut portions 2 arranged in the tubular holder 1 . One of the inner peripheral surface 12 of the holder 1 and the outer peripheral surface of the nut body 20 is provided with a convex portion 11 protruding in the radial direction. The other of the inner peripheral surface 12 of the holder 1 and the outer peripheral surface of the nut body 20 is provided with a concave portion 23 which is recessed in the radial direction and into which the convex portion 11 is fitted. In addition, in this embodiment, the protrusion 11 is provided on the inner peripheral surface 12 of the holder 1 and the recess 23 is provided on the outer peripheral surface of the nut body 20 . The spacer 3 is provided with an annular spacer main body 30 and a spacer concave portion 31 corresponding to the convex portion 11 provided on the inner peripheral surface of the holder 1 on the outer peripheral surface of the spacer 3 .

According to the spacer 3 of Embodiment 1, the spacer concave portion 31 is fitted into the convex portion 11 of the holder 1 and fixed to the holder 1 so as not to rotate. Therefore, the generation of noise and vibration is suppressed. In addition, since the convex portion 11 for fixing the nut portion 2 is used, no special processing or the like is required for the holder 1 . Therefore, manufacturing of the nut device 101 is facilitated.

Although the first embodiment has been described above, the present disclosure is not limited to the first embodiment. Although the holder 1 of Embodiment 1 is provided with the convex portion 11, the spacer of the present disclosure can be applied even if the holder 1 is provided with the concave portion. In addition, there is a nut device 101 in which the projection 11 is detachable. In Modification 1, a spacer applied to a nut device 101 in which a recess 23 is provided in the holder 1 will be described below. Modification 2 describes a case where the projection 11 is applied to a removable nut device 101 .

(Modification 1)
9 is a cross-sectional view of a holder and a nut portion in a nut device according to Modification 1. FIG. 10 is a cross-sectional view of a holder and a spacer in a nut device according to Modification 1. FIG. As shown in FIG. 9, the holder 41 of the nut device 101A of Modification 1 is different from the holder 1 of Embodiment 1 in that it does not have one protrusion 11 (see FIG. 2). Further, the holder 41 differs from the holder 1 of the first embodiment in that it has three recesses 43, 44, and 45. As shown in FIG. The three recesses 43, 44, 45 are arranged at intervals of 120°. On the other hand, the nut portion 42 of the nut device 101A of Modification 1 is different from the nut portion 2 of Embodiment 1 in that it does not have three recesses (see FIG. 3). Further, the nut portion 42 is different from the nut portion 2 of the first embodiment in that it has a convex portion 46 .

In Modification 1, as shown in FIG. 9 , the convex portion 46 of the first nut portion 42 of the three nut portions 42 is fitted into the concave portion 43 of the holder 41 . Although not shown, the projection 46 of the second nut portion 42 is fitted into the recess 44 of the holder 41 . Although not shown, the projection 46 of the third nut portion 42 is fitted into the recess 45 of the holder 41 . As a result, the positions of the S grooves 22 of the respective nut portions 42 can be set in different directions when viewed from the central axis O. As described above, even with the nut device 101A of Modification 1, the phase of each nut portion 2 can be managed.

As shown in FIG. 10 , the spacer 3A according to Modification 1 includes a spacer main body 30 and a spacer projection 32 . The spacer convex portion 32 protrudes radially outward from the outer peripheral portion of the spacer main body 30 . The spacer protrusion 32 has the same shape as the recesses 43 , 44 , 45 of the holder 41 . By fitting the spacer protrusion 32 into one of the recesses 43, 44, and 45 of the holder 41 (in the drawing, the state of fitting into the recess 43 is shown), the rotation of the spacer 3 is prevented. Regulated.

(Modification 2)
FIG. 11 is a perspective view of a holder of modification 2. FIG. FIG. 12 is a cross-sectional view of a nut device having three nut portions in Modification 2, cut so as to overlap the first nut portion. FIG. 13 is a cross-sectional view of a nut device having three nut portions in Modification 2, cut so as to overlap with the second nut portion. FIG. 14 is a cross-sectional view of a nut device having three nut portions in Modification 2, cut so as to overlap with the third nut portion. FIG. 15 is a cross-sectional view of a nut device having two nut portions in Modification 2, cut so as to overlap the first nut portion. FIG. 16 is a cross-sectional view of a nut device having two nut portions in Modification 2, cut so as to overlap the second nut portion. FIG. 17 is a cross-sectional view of a nut device having four nut portions in Modification 2, cut so as to overlap the first nut portion. FIG. 18 is a cross-sectional view of a nut device having four nut portions in Modification 2, cut so as to overlap the second nut portion. FIG. 19 is a cross-sectional view of a nut device having four nut portions in Modification 2, cut so as to overlap the third nut portion. FIG. 20 is a cross-sectional view of a nut device having four nut portions in Modification 2, cut so as to overlap the fourth nut portion.

As shown in FIG. 11 , the nut device 101B of Modification 2 includes a holder 51 instead of the holder 1 . It should be noted that the nut portion 2 of Modification 2 is the same as that of Embodiment 1, and the description thereof is omitted.

As shown in FIG. 11 , the holder 51 includes a cylindrical holder main body 52 and a rod member 53 . An inner peripheral surface 54 of the holder main body 52 is provided with a concave portion 55 for convex portion. The convex concave portion 55 extends in the axial direction and has a quadrangular shape when viewed from the axial direction. Four convex recesses 55 are provided. The four convex recesses 55 are arranged at intervals of 90°.

The rod-shaped member 53 is a quadrangular prism-shaped component. The rod-shaped member 53 is fitted in the concave portion 55 for convex portion. The cross-sectional shape of the rod-like member 53 is larger than the concave portion 55 for convex portion of the holder 51 . In other words, as shown in FIG. 12 , the radially outer half of the rod-shaped member 53 is fitted in the protrusion concave portion 55 , and the radially inner half of the rod-shaped member 53 is radially wider than the inner peripheral surface of the holder body 52 . protrude inward. Therefore, the concave portion 55 for convex portion and the rod-like member 53 cooperate to form a convex portion. Both ends of the rod-like member 53 in the axial direction are in contact with the lids 4 and 5 (see FIG. 1) press-fitted into the holder 51 and do not move in the axial direction.

Moreover, although the rod-like member 53 shown in FIG. 11 is continuous in the axial direction, a plurality of rod-like members divided in the axial direction may be used. In other words, the rod-shaped member 53 may be divided into four in the axial direction and fitted into each of the four concave portions 55 for convex portions.

According to the configuration described above, the phases of the nut portions 2 can be appropriately managed according to the number of the nut portions 2 . The arrangement (phase) of the nut portions 2 corresponding to the number of the nut portions 2 will be described below with reference to FIGS. 12 to 20. FIG.

First, the case where the nut device 101B has three nut portions 2 (the case where the first nut portion 2A, the second nut portion 2B, and the third nut portion 2C are provided) will be described. For the convenience of explanation, the four concave portions 55 for convex portions are referred to as a concave portion 55A for a first convex portion, a concave portion 55B for a second convex portion, a concave portion 55C for a third convex portion, and a concave portion 55D for a fourth convex portion. .

As shown in FIGS. 12 to 14, the rod-like member 53 is used while being continuous in the axial direction. The rod-shaped member 53 is fitted into the recess 55A for the first projection of the holder main body 52 . As shown in FIG. 12, the bar member 53 is fitted into the second recess 23B of the first nut portion 2A. As shown in FIG. 13, the rod-like member 53 is fitted into the first concave portion 23A of the second nut portion 2B. As shown in FIG. 14, the rod-shaped member 53 is fitted into the third recess 23C of the third nut portion 2C. As a result, the S grooves 22 of each nut portion 2 are arranged at intervals of 120°.

Next, the case where the nut device 101B has two nut portions 2 (the case where the first nut portion 2A and the second nut portion 2B are provided) will be described. As shown in FIGS. 15 and 16, the rod-shaped member 53 uses a first rod-shaped member 53A and a second rod-shaped member 53B divided into two. As shown in FIG. 15, the first rod-shaped member 53A is fitted into the recess 55A for the first projection. As shown in FIG. 16, the second rod-shaped member 53B is fitted into the recess 55C for the third projection. Therefore, the positions of the first rod-shaped member 53A and the second rod-shaped member 53B are arranged to differ by 180°.

As shown in FIG. 15, the first rod member 53A is fitted into the first concave portion 23A of the first nut portion 2A. As shown in FIG. 16, the first concave portion 23A of the second nut portion 2B is fitted. As a result, the S grooves 22 of each nut portion 2 are arranged at 180° intervals and evenly arranged in the circumferential direction. The end surface of the first rod member 53A in the second direction X2 abuts the end surface of the second nut portion 2B in the first direction X1 (see the phantom line in FIG. 16). The end surface of the second rod-shaped member 53B in the first direction X1 contacts the end surface of the first nut portion 2A in the second direction X2 (see the phantom line in FIG. 15). Therefore, the first rod-shaped member 53A and the second rod-shaped member 53B do not move in the axial direction.

Next, the case where the nut device 101B has four nut portions 2 (the case where the first nut portion 2A, the second nut portion 2B, the third nut portion 2C, and the fourth nut portion 2D are provided) will be described. As shown in FIGS. 17 to 20, the rod-shaped member 53 uses a first rod-shaped member 53A, a second rod-shaped member 53B, a third rod-shaped member 53C, and a fourth rod-shaped member 53D divided into four. As shown in FIG. 17, the first rod-shaped member 53A is fitted into the recess 55A for the first projection. As shown in FIG. 18, the second rod-shaped member 53B is fitted into the recess 55B for the second projection. As shown in FIG. 19, the third rod-shaped member 53C is fitted into the recess 55C for the third projection. As shown in FIG. 20, the fourth rod-shaped member 53D is fitted into the recess 55D for the fourth projection. That is, the first rod-shaped member 53A, the second rod-shaped member 53B, the third rod-shaped member 53C, and the fourth rod-shaped member 53D are arranged at intervals of 90°.

As shown in FIG. 17, the first rod member 53A is fitted into the first concave portion 23A of the first nut portion 2A. As shown in FIG. 18, the second rod member 53B is fitted into the first concave portion 23A of the second nut portion 2B. As shown in FIG. 19, the third rod member 53C is fitted into the first concave portion 23A of the third nut portion 2C. As shown in FIG. 20, the fourth rod member 53D is fitted into the first concave portion 23A of the fourth nut portion 2D. As a result, the S grooves 22 of each nut portion 2 are arranged at intervals of 90°.

In the nut device 101B described above, the same spacer 3 (see FIG. 7) as in the first embodiment is used. As described above, the spacer 3 has one spacer recess 31 . When there is one rod-like member 53 (when there are three nut portions 2 , see FIGS. 12 to 14), the spacer concave portion 31 is fitted to the rod-like member 53 . When there are two rod-shaped members 53 (when there are two nut portions 2, see FIGS. 15 and 16), the spacer concave portion 31 is fitted to the first rod-shaped member 53A or the second rod-shaped member 53B. When there are four rod-shaped members 53 (when there are four nut portions 2, see FIGS. 17 to 20), the spacer recesses 31 are formed in the rod-shaped members that fit into the recesses 23 of the nut portions 2 adjacent in the axial direction. Mate. Thereby, the rotation of the spacer 3 is restricted.

In the following second embodiment, a spacer with a different nut device will be described.

(Embodiment 2)
FIG. 21 is an axial cross-sectional view of the ball screw device of Embodiment 2. FIG. 22 is a side view of the holder of Embodiment 2 as seen from the first direction. FIG. FIG. 23 is an exploded perspective view of a nut portion, a spacer, and a rod-shaped member according to Embodiment 2; As shown in FIG. 21, the nut device 101C of the second embodiment includes a cylindrical holder 60, one lid portion 61, a plurality of nut portions 70, a rod-shaped member 80, and a plurality of spacers 90. Prepare.

The holder 60 of the second embodiment includes a holder main body 62, a protrusion 63 protruding radially inward from an end portion in the first direction X1 on an inner peripheral surface 62a of the holder main body 62, and axially penetrating the protrusion 63. A holder holding hole 64 and a female threaded portion 65 provided at the end of the inner peripheral surface 62a of the holder main body 62 in the second direction X2 are provided. Therefore, the holder 60 of the second embodiment differs from the holder 1 of the first embodiment in that it does not have the protrusion 11 (see FIGS. 1 and 2). Further, the holder 60 of the second embodiment differs from the holder 1 of the first embodiment in that it has a projecting portion 63 , a holder holding hole 64 , and a female screw portion 65 .

As shown in FIG. 22, the inner peripheral surface 62a and the outer peripheral surface 62b of the holder body 62 are circular. The projecting portion 63 extends in the circumferential direction along the inner peripheral surface 62a of the holder body 62 and has an annular shape. The holder holding hole 64 has the same cross-sectional shape as the rod-shaped member 80 and has a non-circular shape when viewed from the axial direction.

In this embodiment, the holder main body 62 and the projecting portion 63 are manufactured by processing a single material and are integrated. That is, the holder main body 62 and the projecting portion 63 are inseparable, and the number of parts is reduced. Note that the present disclosure is not limited to the case where the holder main body 62 and the projecting portion 63 are non-separable. In other words, the projecting portion 63 and the holder main body 62 may be separate bodies. According to this, since no projecting portion is provided on the inner peripheral side of the holder main body 62, machining of the inner peripheral side of the holder main body 62 is facilitated. Therefore, the inner diameter of the holder main body 62 can be processed with high precision. Moreover, the manufacture of the holder main body 62 is facilitated, and the cost can be reduced. The protrusion is fixed to the holder main body 62 by forming thread grooves on the inner peripheral surface of the holder main body and the outer peripheral surface of the protrusion, and screwing the protrusion onto the holder main body 62 . Alternatively, a method of fixing the projecting portion to the end surface of the holder main body 62 by tightening with a bolt in the axial direction can be used. Alternatively, a method of press-fitting a projecting portion into the inner peripheral side of the holder main body 62 and fixing by fitting can be used.

As shown in FIG. 21 , the female threaded portion 65 is a thread groove provided in the inner peripheral surface 62 a of the holder body 62 . Then, the screw grooves on the outer peripheral surface of the lid portion 61 are screwed together, and the lid portion 61 is fixed to the holder main body 62 .

As shown in FIG. 23 , the nut portion 70 of Embodiment 2 includes a nut body 71 , an inner circumferential raceway surface 72 , an S groove 73 , and one nut holding hole 74 . The nut portion 70 of the second embodiment differs from the nut portion 2 of the first embodiment in that it does not have a plurality of recesses 23 (see FIG. 3). Further, the nut portion 70 of the second embodiment differs from the nut portion 2 of the first embodiment in that one nut holding hole 74 is provided.

The nut holding hole 74 has the same cross-sectional shape as the rod-shaped member 80 when viewed from the axial direction. The nut holding hole 74 is formed by recessing the outer peripheral surface of the nut body 71 radially inward. The nut holding hole 74 is disposed at a point-symmetrical position with respect to the S groove 73 about the central axis O (a position rotated by 180°). The three nut portions 70 are referred to as a first nut portion 70A, a second nut portion 70B, and a third nut portion 70C in order from the first direction X1 toward the second direction X2.

As shown in FIG. 23 , the spacer 90 of the second embodiment includes a spacer main body 91 and a plurality of spacer holding holes 92 . Therefore, the spacer 90 of the second embodiment differs from the spacer 3 of the first embodiment in that the number of spacer holding holes 92 is not singular but plural (see FIG. 7).

Three spacer retaining holes 92 are provided corresponding to the number of nut portions 70 in this embodiment. The three spacer holding holes 92 are arranged at intervals of 120°. Hereinafter, the three spacer retaining holes 92 are referred to as a first spacer retaining hole 92A, a second spacer retaining hole 92B, and a third spacer retaining hole 92C. The spacer holding hole 92 is formed by denting the outer peripheral surface of the spacer body 91 radially inward. The spacer retaining hole 92 of this embodiment has the same cross-sectional shape as the rod-like member 80 when viewed from the axial direction.

The rod-like member 80 is a component having a non-circular cross-sectional shape, and is divided into five pieces in the axial direction. Hereinafter, they are referred to as a first rod-shaped member 81, a second rod-shaped member 82, a third rod-shaped member 83, a fourth rod-shaped member 84, and a fifth rod-shaped member 85 in order from the first direction X1 toward the second direction X2. Hereinafter, the first rod-shaped member 81 may be referred to as a holder rod-shaped member. Further, the second rod-shaped member 82, the third rod-shaped member 83, the fourth rod-shaped member 84, and the fifth rod-shaped member 85 may be collectively referred to as a nut rod-shaped member.

The first rod-shaped member 81 has an end in the first direction X1 fitted into the holder holding hole 64 of the holder 60, and an end in the second direction X2 fitted into the nut holding hole 74 of the first nut portion 70A. are doing. Thereby, the first nut portion 70A is fixed to the holder 60 so as not to rotate. If the holder holding hole 64 is above the central axis O when viewed from the first direction X1, the S groove 73 of the first nut portion 70A is arranged below the central axis O (see FIG. 22). see dot area).

The second rod-shaped member 82 has a first direction end fitted into the nut holding hole 74 of the first nut portion 70A and a second direction end fitting into the first spacer holding hole 90A of the first spacer 90A. 92A. Thereby, the first spacer 90A is fixed to the holder 60 so as not to rotate.

The third rod-shaped member 83 has an end in the first direction X1 fitted into the third spacer holding hole 92C of the first spacer 90A, and an end in the second direction X2 for the nut of the second nut portion 70B. It fits in the holding hole 74 . Thereby, the second nut portion 70B is fixed to the holder 60 so as not to rotate. Further, when the holder holding hole 64 is above the central axis O as viewed from the first direction X1, the S groove 73 of the second nut portion 70B is arranged on the upper left side of the central axis O (Fig. 22 dot area).

The fourth rod member 84 has an end in the first direction X1 fitted into the nut holding hole 74 of the second nut portion 70B, and an end in the second direction X2 for the third spacer of the second spacer 90B. It fits in the holding hole 92C. Thereby, the second spacer 90B is fixed to the holder 60 so as not to rotate.

The fifth rod-shaped member 85 has a first direction end fitted into the second spacer retaining hole 92B of the second spacer 90B and a second direction end fitting into the nut retaining hole of the third nut portion 70C. 74 is fitted. Thereby, the third nut portion 70C is fixed to the holder 60 so as not to rotate. In addition, when the holder holding hole 64 is located above the central axis O as viewed from the first direction X1, the S groove 73 of the third nut portion 70C is arranged on the upper right side of the central axis O (Fig. 22 dot area).

As shown in FIG. 21, the end surface of the first nut portion 70A in the first direction X1 abuts on the projection of the holder 60. As shown in FIG. Further, the end surface of the third nut portion 70C in the second direction X2 is in contact with the lid portion. Therefore, each nut 70 and the spacer 90 do not come off from the holder main body.

As described above, in the nut device 101C of the second embodiment, the first nut portion 70A, the second nut portion 70B, and the third nut portion 70C are arranged in a phase-shifted state at intervals of 120°. Therefore, the S grooves of each nut portion are arranged at intervals of 120° and are evenly arranged in the circumferential direction.

As described above, the spacer 90 of the second embodiment is a nut device spacer interposed between the plurality of nut portions 70 arranged in the tubular holder 60 . The nut portion 70 has an annular nut body 71 and a nut holding hole 75 that penetrates the nut body 71 in the axial direction and into which one end of the rod-shaped member 80 is inserted. The nut device spacer has an annular spacer main body 91 and a spacer holding hole 92 that passes through the spacer main body 91 in the axial direction and into which the rod-like member 80 is inserted. A plurality of spacer holding holes 92 are provided while being spaced apart from each other in the circumferential direction.

According to the second embodiment, the rotation of each spacer 90 can be restricted while controlling the phase of the nut portion 70 .

FIG. 24 is an exploded perspective view of the nut portion, the spacer, and the rod-shaped member of Modification 3. FIG. In addition, in Embodiment 2, the cross-sectional shape of the rod-shaped member 80 is non-circular, but the present disclosure is not particularly limited. For example, as shown in a nut device 101D of Modified Example 3 of Embodiment 2 in FIG. 24, a cylindrical member may be used as the rod-shaped member 80A. In response to the shape change of the rod-shaped member 80A, the holder holding hole (not shown in FIG. 24), the nut holding hole 75, and the spacer holding hole 93 are formed as circular through holes penetrating in the axial direction. good too.

Further, the rod-shaped member 80 of the second embodiment connects two axially adjacent parts with one rod-shaped member, but the rod-shaped member of the present disclosure connects three axially continuous parts. You may make it Specifically, as shown in FIG. 24, a rod-shaped member 80A of Modification 3 is divided into three in the axial direction, and includes a first rod-shaped member 81A, a second rod-shaped member 82A, and a third rod-shaped member 83A. . The first rod-shaped member 81A passes through a holder holding hole (not shown in FIG. 24), a nut holding hole 75 of the first nut portion 70A, and a spacer holding hole 93B of the first spacer 90A. ing. The second rod member 82A passes through the spacer holding hole 93A of the first spacer 90A, the nut holding hole 75 of the second nut portion 70B, and the spacer holding hole 93A of the second spacer 90B. are doing. The third rod-shaped member 83A passes through the spacer holding hole 93C of the second spacer 90B and the nut holding hole 75 of the third nut portion 70C. Even with such a rod-shaped member 80A, each nut portion 70 and each spacer 90 can be fixed to the holder so as not to rotate while managing the phase of each nut portion 70 .

25 is a perspective view of a spacer according to Modification 4. FIG. 26 is a side view of a spacer according to Modification 4. FIG. Next, an example in which the spacer 90 of the second embodiment is modified will be described. A spacer 95 according to Modification 4 includes a spacer main body 91 , three spacer holding holes 92 , and a plurality of S-groove recesses 96 . Therefore, the spacer 95 of Modification 4 differs from the spacer 90 of the second embodiment in that it includes an S-groove concave portion 96 . The S-groove concave portion 96 is formed by recessing a part of the side surface of the spacer body 91 facing the axial direction.

The S-groove recesses 96 are provided at intervals of 120°. The S-groove recessed portion 96 is provided on both side surfaces of the spacer body 91 (a side surface 91a facing the first direction X1 and a side surface 91b facing the second direction X2). Therefore, the spacer 95 has a total of six S-groove recesses 96 . The S-groove recessed portion 96 is positioned symmetrically about the central axis O with respect to the spacer holding hole 92 (rotated by 180°). Note that the S groove 73 is located at a position rotated 180° from the nut holding hole 74 . Therefore, when the nut portion 70 and the spacer 95 are connected by the bar member 80, the S groove 73 axially overlaps with one of the three S groove concave portions 96 arranged in the circumferential direction.

The S-groove recessed portion 96 extends in the circumferential direction. The angle formed by an imaginary line L1 connecting one end of the S-groove recess 96 in the circumferential direction and the central axis O and an imaginary line L2 connecting the other end in the circumferential direction of the S-groove recess 96 and the central axis O is θ1. . The angle between a virtual line L3 connecting one end of the S groove 73 in the circumferential direction and the central axis O and a virtual line L4 connecting the other end in the circumferential direction of the S groove 73 and the central axis O is θ2. And the angle θ1 is larger than the angle θ2. That is, the circumferential length of the S-groove recess 96 is longer than the circumferential length of the S-groove 73 when viewed from the axial direction. Therefore, when viewed from the axial direction, the S groove 73 is contained within the area of the S groove concave portion 96 (see the virtual line of the S groove 73 in FIG. 26).

As described above, according to Modification Example 4, the nut portion 70 axially adjacent to the spacer 95 receives an axial pressure load from the side surface 91a (or side surface 91b) of the spacer body 91, but the nut portion 70 is A portion of the direction where the S-groove 73 is provided faces the S-groove concave portion 96 and is not subjected to a pressing load.

As described above, the spacer 95 of Modification 4 has the S-groove concave portion 96 formed by recessing a part of the spacer main body 91 in the axial direction. The S-groove recessed portion 96 overlaps the S-groove 73 provided in the nut portion 70 when viewed from the axial direction.

Here, when the balls 103 roll in the S groove 73 in the ball screw device 100, the balls 103 are separated from the outer circumference raceway surface 102a (see FIG. 1) of the screw shaft 102. As shown in FIG. Therefore, the portion of the nut body 71 in the circumferential direction where the S groove 73 is provided is not supported by the screw shaft 102 via the ball 103, and has low support rigidity. Further, according to the spacer 95 of Modification 4, the pressing load does not act on the portion of the nut portion 70 in the circumferential direction where the S groove 73 is provided. Therefore, deformation of the portion of the nut portion 70 in the circumferential direction where the S groove 73 is provided is avoided.

In Embodiment 2, Modification 3, and Modification 4, an example in which the nut is fixed by one rod-shaped member has been described. Next, Embodiment 3 in which the nut is fixed by a plurality of rod-shaped members will be described. .

(Embodiment 3)
FIG. 27 is an axial cross-sectional view of the ball screw device of Embodiment 3. FIG. 28 is a side view of the holder of Embodiment 3 as viewed from the first direction. FIG. 29 is an exploded perspective view of a nut portion, a spacer, and a rod-shaped member according to Embodiment 3. FIG. A nut device 101E of the third embodiment includes a holder 110, a lid portion 111, three nut portions 120, three rod-shaped members 130, and two spacers 140.

The holder 110 of Embodiment 3 includes a holder main body 112 , a projecting portion 113 , a plurality of holder holding holes 114 (see FIG. 25 ), and a female screw portion 115 . Therefore, the holder 110 of the third embodiment differs from the holder 60 of the second embodiment in that it has a plurality of holder holding holes 114 instead of one holder holding hole 64 (see FIG. 21).

As shown in FIG. 25, the holder holding holes 114 of the third embodiment are arranged at intervals of 120° and are equally spaced in the circumferential direction. It is different from the second embodiment in that three are provided. The three holder holding holes 114 are arranged at intervals of 120°. The holder holding hole 114 has a circular shape when viewed from the axial direction, and has the same cross-sectional shape as the rod-shaped member 130 .

The nut portion 120 includes a nut body 121 , an inner raceway surface 122 , an S groove 123 and three nut holding holes 124 . Therefore, the nut portion 120 of the third embodiment differs from the nut portion 70 of the second embodiment in that it has three nut holding holes 124 instead of one nut holding hole 74 (see FIG. 22). . The holder holding holes 114 are arranged at intervals of 120°. It has a circular shape when viewed from the axial direction, and has the same cross-sectional shape as the rod-like member.

The spacer 140 of the third embodiment is the same as the spacer 90 of the second embodiment. The spacer 140 includes an annular spacer main body 141 and three spacer holding holes 142 . The spacer holding holes 142 are arranged at intervals of 120°. The spacer main body 141 has a circular shape when viewed from the axial direction, and has the same cross-sectional shape as the rod-like member.

The rod-shaped member 130 is a columnar component. The axial length of the rod-shaped member 130 is the same as the axial length of the protrusions 113, the three nut portions 120, and the two spacers 140 of the holders 110 arranged in the axial direction. Therefore, the rod-shaped member 130 of Embodiment 3 is longer than the rod-shaped member of Embodiment 2, and is not divided in the axial direction.

Each of the rod-shaped members 130 passes through the nut holding hole 124 of the nut portion 120 and the spacer holding hole 142 of the spacer 140 . An end portion of the rod-shaped member 130 in the first direction is fitted into the holder holding hole 114 of the holder 110 . Thereby, each nut portion 120 and spacer 140 are fixed to the holder 110 so as not to rotate.

Also, the three nut portions 120 (the first nut portion 120A, the second nut portion 120B, and the third nut portion 120C) are arranged in a phase-shifted state at intervals of 120°. Therefore, the S grooves of each nut portion are arranged at intervals of 120° and are evenly arranged in the circumferential direction. Moreover, each nut portion and each spacer are fixed by a plurality of rod-shaped members, and the fixing strength is high.

With the nut device 101E of Embodiment 3 as well, the S grooves 123 can be arranged in different directions when viewed from the central axis O, and the phase of the nut portion 120 can be managed.

In addition, although the case where the number of the nut parts 120 is three was demonstrated in Embodiment 3, you may change the number of the nut parts 120 to two or four in this indication. When the number of nut portions 120 is changed, the bar member 130, the nut holding hole 124, and the holder holding hole 114 are also changed in accordance with the change in the number of the nut portions 120. must be the same number.

Although each embodiment and each modified example have been described above, the shape and size of the S-groove concave portion 96 are not particularly limited in the present disclosure. For example, in the S-groove recessed portion 96 of Modification 4, the inner peripheral side of the side surfaces 91a and 91b of the spacer 95 is recessed, but the outer peripheral side may also be recessed. Further, the S-groove concave portion 96 of the fourth modification may be applied to the spacers 3 and 3A shown in the first embodiment and the first modification. Also, the number of S-groove recesses 96 provided on one side surface may be appropriately changed according to the number of nut portions.

1, 41, 51, 60, 110 holder 2, 42, 70, 120 nut portion 3, 90, 95, 140 spacer (nut device spacer)
4, 5, 111 lid portion 10, 52, 62, 112 holder main body 11, 46 convex portion 20, 71, 121 nut main body 21, 72, 122 inner circumference raceway surface 22, 73, 123 S groove 23, 43, 44, 45 recesses 30, 91, 141 spacer main body 31 recesses for spacers 53, 80, 80A rod-shaped member 55 recesses for projections 63 projections 64, 114 holding holes for holders 74, 124 holding holes for nuts 81, 81A first rod-shaped member Members 82, 82A Second rod-shaped member 83, 83A Third rod-shaped member 84 Fourth rod-shaped member 85 Fifth rod-shaped member 92, 142 Spacer holding hole 96 S-groove recess 100 Ball screw device 101, 101A, 101B, 101C, 101D, 101E nut device 102 screw shaft 103 ball 130 bar member

Claims (3)

A nut device spacer interposed between a plurality of nut portions arranged in a cylindrical holder,
One of the inner peripheral surface of the holder and the outer peripheral surface of the nut portion is provided with a convex portion projecting in a radial direction,
The other of the inner peripheral surface of the holder and the outer peripheral surface of the nut portion is provided with a concave portion that is recessed in the radial direction and into which the convex portion is fitted,
The nut device spacer is
an annular spacer body;
A nut device spacer, wherein an outer peripheral surface of the spacer is provided with a spacer concave portion or a spacer convex portion corresponding to the convex portion or the concave portion provided on the inner peripheral surface of the holder. A nut device spacer interposed between a plurality of nut portions arranged in a cylindrical holder,
The nut portion
a ring-shaped nut body;
a nut holding hole axially penetrating the nut body and into which a rod-shaped member is inserted;
has
The nut device spacer is
an annular spacer body;
having a spacer holding hole that passes through the spacer main body in the axial direction and into which the rod-like member is inserted;
A plurality of the spacer holding holes are provided while being separated from each other in the circumferential direction. having an S-groove recess formed by recessing a part of the spacer body in the axial direction,
The spacer for a nut device according to claim 1 or 2, wherein the S-groove recess overlaps an S-groove provided in the nut portion when viewed from the axial direction.

Images