Nut and ball screw device

Abstract

To provide a nut having excellent operability.SOLUTION: The nut includes a nut main body and a circulation component. The nut main body has: an inner peripheral raceway surface provided on an inner peripheral surface; a housing portion formed by recessing a part of an outer peripheral surface of the nut main body; a bearing surface forming a bottom surface of the housing portion; and a through hole penetrating through the bearing surface and the inner peripheral surface of the nut main body. The circulation component has: a circulation component main body disposed on the housing portion and the through hole; and an arm portion kept into contact with the bearing surface. The circulation component main body includes: a first opening opened toward a raceway; and a ball passage extending from the first opening along a tangential line of a virtual circle formed by connecting centers of a plurality of balls rolling on the raceway. An inner surface of the ball passage has: an inner peripheral-side rolling surface disposed at an inner peripheral side with respect to the tangential line; and an outer peripheral-side rolling surface disposed at an outer peripheral side with respect to the tangential line. At least a part close to the first opening of the outer peripheral-side rolling surface is a groove surface. The groove surface is continued to an edge portion of the inner peripheral raceway surface cut out by the through hole.SELECTED DRAWING: Figure 14

Description

[Technical Field]

[0001] The present disclosure relates to a nut and a ball screw device. [Background technology]

[0002] The ball screw device includes a nut, a screw shaft that passes through the nut, and a plurality of balls that roll on a raceway between the nut and the screw shaft. The nut includes a nut body and a circulating part. The circulating part circulates the balls that have moved from one end of the raceway to the other end of the raceway back to the one end of the raceway.

[0003] One example of a recirculating part is a middle deflector. The middle deflector is generally disposed in a recess provided on the outer peripheral surface of the nut body. As a method for fixing such a middle deflector, the following patent document discloses a method in which a through hole extending axially from the end face of the nut body is provided in each of the nut body and the middle deflector. A pin is then inserted into the through hole. As a result, the middle deflector is caught on the pin and does not come off the nut body. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-289302 Summary of the Invention [Problem to be solved by the invention]

[0005] The balls are transferred between the nut's return path and the circulating part, or between the track and the circulating part. Hereinafter, the transfer of balls with the circulating part may be referred to as operability. There has been a demand for a nut with excellent operability.

[0006] The present disclosure has been made in view of the above, and aims to provide a nut and a ball screw device with excellent operability. [Means for solving the problem]

[0007] To achieve the above object, a nut according to one embodiment of the present disclosure includes a cylindrical nut body that is inserted through a screw shaft, and a circulatory component that is assembled to the nut body. The nut body has an inner circumferential raceway surface that faces the outer circumferential raceway surface of the screw shaft, a housing portion formed by recessing a portion of the outer circumferential surface of the nut body, a seating surface that forms the bottom surface of the housing portion, and a through-hole that penetrates the seating surface and the inner circumferential surface of the nut body and cuts out a portion of the inner circumferential raceway surface. The circulatory component includes a circulatory component body that is disposed in the housing portion and the through-hole, and an arm that extends from the circulatory component body and abuts against the seating surface. The circulatory component body includes a first opening that opens toward a raceway between the outer circumferential raceway surface and the inner circumferential raceway surface, and a ball passage that extends from the first opening along a tangent to an imaginary circle that connects the centers of multiple balls that roll on the raceway. The inner surface of the ball passage has an inner rolling surface located inward of the tangent line and an outer rolling surface located outward of the tangent line. At least a portion of the outer rolling surface near the first opening is a groove surface. The groove surface is continuous with the edge of the inner raceway surface cut out by the through hole.

[0008] According to the invention, when a ball passes through the first opening, it rolls continuously between the groove surface and the inner circumferential raceway surface. This allows for smooth transfer of the ball between the ball passage and the raceway. Furthermore, with a groove surface, the sum of the curvatures with the ball is smaller than when the outer circumferential rolling surface is flat. In other words, the contact ellipse between the groove surface and the ball becomes larger, reducing the surface pressure. This suppresses wear on the groove surface.

[0009] In a preferred embodiment of the nut, the ball passage has a curved portion for changing the direction of movement of the balls, and the outer circumferential rolling surface is flat at the curved portion.

[0010] Normally, the speed at which the ball moves slows down at curved sections of the ball passage, making it easy for the ball to become stuck. If the surface surrounding the curved section includes a grooved surface, the ball moves along the grooved surface, reducing the degree of freedom in which the ball can move. On the other hand, if the surface surrounding the curved section includes a flat surface, the degree of freedom in which the ball can move increases. Therefore, the ball is less likely to become stuck in the curved section. As a result, the ball moves smoothly through the curved section. In addition, the generation of contact noise caused by balls coming into contact with each other is also suppressed.

[0011] In a preferred embodiment of the nut, the circulation component body has a second opening, which is an opening of the ball passage, provided on the opposite side to the first opening, and the outer circumferential rolling surface is a groove surface extending from the first opening to the second opening.

[0012] According to the above configuration, the second opening is also provided with a groove surface, which allows smooth transfer of balls between the ball passage and the return path.

[0013] In a preferred embodiment of the nut, the groove shape of the edge of the groove surface is larger than the groove shape of the edge of the inner circumferential raceway surface.

[0014] Even if the circulation device is misaligned in the axial direction, the groove surface is unlikely to be positioned inside the inner raceway surface, which means that the balls are prevented from coming into contact with the edges of the groove surface, which would impair smooth ball transfer.

[0015] In a preferred embodiment of the nut, the circulation component body has a second opening, which is an opening of the ball passage and is provided on the opposite side to the first opening, and the second opening is chamfered.

[0016] This allows smooth delivery of balls between the ball passage and the return path.

[0017] In a preferred embodiment of the nut, the circulating component is formed by joining an inner component and an outer component separated by a separating surface extending along the ball passage when viewed from an axial direction parallel to the screw shaft. The groove surface is provided in the outer component.

[0018] According to the present disclosure, it is easier to form the groove surface than to form the groove surface on the inner peripheral side part, which makes it easier to manufacture the circulating part.

[0019] In a preferred embodiment of the nut, the circulating part is formed by joining an inner part and an outer part which are divided by a dividing surface extending along the ball passage when viewed from an axial direction parallel to the screw shaft. The groove surface is provided in the inner part.

[0020] According to the above configuration, the load acting on the groove surface toward the outer periphery acts on the inner periphery component, not on the outer periphery component, thereby preventing the outer periphery component from separating from the inner periphery component.

[0021] In a preferred embodiment of the nut, the nut body is arranged on both sides of the accommodating portion in the axial direction parallel to the screw shaft and has a pair of side surfaces facing each other. The accommodating portion is arch-shaped when viewed from the axial direction. A direction parallel to the seating surface when viewed from the axial direction is the seating surface direction. A direction perpendicular to the seating surface and in which the seating surface faces is a first vertical direction. The circulating part has a rib that protrudes from the arm portion in the first vertical direction and extends in the seating surface direction along the side surface, and a crimped portion formed by crimping at least a portion of the rib toward the side surface. The pair of side surfaces are provided with recesses that are grooves extending in the seating surface direction, face the rib in the axial direction, and into which the crimped portion fits.

[0022] According to this configuration, when a load acts on the circulative component in the first vertical direction, the crimped portion is caught in the recessed portion, and therefore the circulative component does not shift in position in the first vertical direction. In other words, the circulative component does not come off the nut body.

[0023] In a preferred embodiment of the nut, the through hole penetrates a central portion of the seat in the seat direction. The seat has a first seat located on one side of the through hole in the seat direction and a second seat located on the other side of the through hole in the seat direction. The arm portion has a first arm portion extending from the circulation component body in one side of the seat direction and abutting against the first seat surface, and a second arm portion extending from the circulation component body in the other side of the seat direction and abutting against the second seat surface. The rib and the crimping portion are provided on each of the first arm portion and the second arm portion.

[0024] If the contact point between the circulating part and the seating surface is only on one side, from the through hole toward the seating surface, the circulating part may tilt. Incidentally, a tilted circulating part means that a part of the circulating part body falls into the through hole, causing the arm portion to float above the seating surface. Furthermore, if the circulating part tilts, the tongue becomes misaligned. Therefore, balls are not scooped up smoothly. On the other hand, according to the above configuration, the circulating part has a first arm portion and a second arm portion. In other words, the circulating part contacts the seating surface on both sides of the through hole toward the seating surface. Therefore, the posture of the circulating part is stable, and balls are scooped up smoothly. Furthermore, since the crimping portions are provided on each arm portion and there are many crimping points, the circulating part can be firmly prevented from coming loose.

[0025] In a preferred embodiment of the nut, the circulating part is formed by joining an inner part and an outer part which are divided by a dividing surface extending along the ball passage when viewed from the axial direction, the inner part has the first arm portion, and the outer part has the second arm portion.

[0026] Even if the connection between the inner and outer components is released, the inner and outer components each have one arm, so the inner and outer components will not fall out of the through hole or come off the nut body.

[0027] In a preferred embodiment of the nut, the circulatory part is formed by joining an inner part and an outer part divided by a dividing surface extending along the ball passage when viewed from the axial direction. The outer part has an outer divided surface extending along the dividing surface, and the first arm portion and the second arm portion. The inner part has an inner divided surface extending along the dividing surface. One of the inner divided surface and the outer divided surface is provided with a protrusion that protrudes toward the seating surface and extends in the axial direction. The other of the inner divided surface and the outer divided surface is provided with a groove that is recessed toward the seating surface and extends in the axial direction, into which the protrusion fits.

[0028] Furthermore, even if the connection between the inner and outer peripheral components were to be released, the outer peripheral component would have two arms. Therefore, the outer peripheral component would not fall into the through hole or separate from the nut body. On the other hand, the inner peripheral component would not shift in position in a direction parallel to the perpendicular to the seating surface because the ridges are caught in the grooves. Therefore, the inner peripheral component would not fall into the through hole.

[0029] In a preferred embodiment of the nut, the dividing surface has an inclined surface that is parallel to the tangent line when viewed from the axial direction and is positioned on one side of the seating surface direction as it approaches the first vertical direction, and a vertical surface that is positioned on one side of the seating surface direction relative to the inclined surface and extends in the first vertical direction. The protrusion and the groove are provided on the vertical surface. The inclined surface restricts movement of the inner peripheral part in a direction that releases the engagement between the protrusion and the groove.

[0030] According to this configuration, even if the joining between the inner peripheral part and the outer peripheral part is released, the engagement between the protrusion and the groove is not released, and therefore the inner peripheral part does not fall out of the through hole.

[0031] In a preferred embodiment of the nut, the pair of side surfaces include a first side surface located on one side of the circulating component in the axial direction and a second side surface located on the other side of the circulating component in the axial direction. The rib includes a first rib extending along the first side surface and a second rib extending along the second side surface. The crimped portion includes a first crimped portion that is part of the first rib and crimped toward the first side surface, and a second crimped portion that is part of the second rib and crimped toward the second side surface.

[0032] According to this configuration, since there are many crimped portions that catch on the nut body, the circulating part can be firmly prevented from coming off.

[0033] In addition, in order to achieve the above-mentioned object, a ball screw device according to one aspect of the present disclosure includes the nut, a screw shaft passing through the nut, and a plurality of balls arranged between the nut and the screw shaft.

[0034] According to the ball screw device of the present disclosure, when the ball is transferred between the ball passage and the raceway, the behavior of the ball is stabilized and the transfer is smooth. [Effects of the Invention]

[0035] According to the nut and ball screw device of the present disclosure, a pin for fixing the circulating part is not required, and an increase in the number of parts is suppressed. [Brief explanation of the drawings]

[0036] [Figure 1] FIG. 1 is a side view of the ball screw device of the first embodiment as viewed from a direction perpendicular to the axial direction. [Figure 2] FIG. 2 is a cross-sectional view of the nut of the first embodiment cut in the axial direction. [Figure 3A] 3A is a cross-sectional view of the nut body taken along line III-III in FIG. 1 and viewed from the direction of the arrows. [Figure 3B] FIG. 3B is a view seen from the direction of arrow IIIB in FIG. 3A. [Figure 4] FIG. 4 is a side view seen from the direction of arrow IV in FIG. 3A. [Figure 5] FIG. 5 is a side view seen from the direction of arrow V in FIG. 3A. [Figure 6] FIG. 6 is an enlarged view of the middle deflector and its surroundings in FIG. [Figure 7] FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. [Figure 8] FIG. 8 is a perspective view of the middle deflector of the first embodiment before crimping, viewed from a first vertical direction. [Figure 9] FIG. 9 is a perspective view of the middle deflector of the first embodiment before crimping, viewed from a second vertical direction. [Figure 10] FIG. 10 is a cross-sectional view taken along line XX in FIG. [Figure 11] FIG. 11 is a cross-sectional view taken along line XI-XI in FIG. [Figure 12] FIG. 12 is a side view seen from the direction of arrow XII in FIG. [Figure 13] FIG. 13 is a perspective view of the inner peripheral side part of the first embodiment. [Figure 14] FIG. 14 is an enlarged view of the vicinity of the first opening shown in FIG. [Figure 15] FIG. 15 is a perspective view of the outer peripheral side part of the first embodiment. [Figure 16A] FIG. 16A is a view seen from the direction of arrow XVI in FIG. [Figure 16B] FIG. 16B is a diagram showing a state in which the middle deflector is displaced in the axial direction from the state in FIG. 16A. [Figure 16C] FIG. 16C is a diagram showing a state in which the middle deflector is displaced in the vertical direction from the state in FIG. 16A. [Figure 17A] FIG. 17A is a perspective view showing a preparation step of the assembling method of the first embodiment. [Figure 17B] FIG. 17B is a side view of the state before crimping in the crimping step of the assembling method of the first embodiment, as viewed from the second seating surface direction. [Figure 17C]17C is a side view of the state after crimping in the crimping step of the assembling method of the first embodiment, as viewed from the second seating surface direction. FIG. [Figure 17D] FIG. 17D is a plan view showing the crimping step of the first embodiment as viewed from the first vertical direction. [Figure 17E] FIG. 17E is a perspective view showing a state in which crimping is performed with two jigs in the crimping step of the first embodiment. [Figure 18] FIG. 18 is a side view of the nut of the second embodiment, seen from the second bearing surface direction, in a state before the rib is crimped. [Figure 19] FIG. 19 is a side view of the nut of the second embodiment after the rib has been crimped, as viewed from the second bearing surface direction. [Figure 20] FIG. 20 is a side view of the nut of the third embodiment, seen from the second bearing surface direction, in a state before the rib is crimped. [Figure 21] FIG. 21 is a side view of the nut of the third embodiment after the rib has been crimped, as viewed from the second bearing surface direction. [Figure 22] FIG. 22 is a perspective view of the middle deflector of the fourth embodiment as viewed from the second axial direction. [Figure 23] FIG. 23 is an enlarged view of the gap between the second side surface and the second opposing surface in the nut of the fourth embodiment, viewed from the first vertical direction. [Figure 24A] FIG. 24A is a perspective view of the middle deflector of the fifth embodiment. [Figure 24B] FIG. 24B is a perspective view of the outer peripheral side part of the fifth embodiment. [Figure 25] FIG. 25 is a side view of the middle deflector of the sixth embodiment as viewed from the first axis direction. [Figure 26] FIG. 26 is a cross-sectional view of the middle deflector of the sixth embodiment taken along a plane extending in the seating direction and vertical direction. [Figure 27] FIG. 27 is a side view of the middle deflector of the seventh embodiment as viewed from the first axis direction. [Figure 28] FIG. 28 is a perspective view of an inner peripheral side part of the middle deflector of the eighth embodiment. [Figure 29] FIG. 29 is a perspective view of an outer peripheral side part of the middle deflector of the eighth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0037] The following detailed description of the preferred embodiments of the present invention will be given with reference to the accompanying drawings. The present disclosure is not limited to the content of the following description. The components described below include those that can be easily imagined by a person skilled in the art and those that are substantially the same. Furthermore, the components described below can be combined as appropriate.

[0038] (Embodiment 1) Fig. 1 is a side view of a ball screw device of embodiment 1 as viewed from a direction perpendicular to the axial direction. As shown in Fig. 1, the ball screw device 100 includes a nut 101, a screw shaft 102 that penetrates the nut 101, and a plurality of balls 103 (see Fig. 2) that are arranged between the nut 101 and the screw shaft 102. The screw shaft 102 is a cylindrical component made of steel. A spiral outer circumferential raceway surface 102a is provided on the outer circumferential surface of the screw shaft 102. Hereinafter, the direction parallel to the axis O of the screw shaft 102 will be referred to as the axial direction.

[0039] The ball screw device 100 is a device that converts rotational motion into linear motion and linear motion into rotational motion. In this embodiment, an inner ring 104 is provided on the outer peripheral surface of a nut 101. The inner ring 104 is disposed on the outer peripheral surface of the nut 101 near the axial end. Hereinafter, the direction in which the inner ring 104 is disposed as viewed from the axial center of the nut 101 will be referred to as a first axial direction (one axial direction) X1. The opposite direction of the first axial direction X1 will be referred to as a second axial direction (the other axial direction) X2.

[0040] The inner ring 104 is a component of a bearing that rotatably supports the nut 101. An outer peripheral raceway 105 on which balls roll is provided on the outer peripheral surface of the inner ring 104. Thus, in this embodiment, the nut 101 is rotatably supported in a housing or the like (not shown), and the screw shaft 102 moves linearly in the axial direction. In other words, the ball screw device 100 of this embodiment is designed to convert rotational motion into linear motion. Note that this embodiment illustrates a nut integrally formed with the inner ring, but the present disclosure may also apply to a nut that is not integrally formed with the inner ring. Furthermore, the present disclosure may also be applied to a ball screw device that converts linear motion into rotational motion.

[0041] Fig. 2 is a cross-sectional view taken along the axial direction of the nut of embodiment 1. As shown in Fig. 2, the nut 101 includes a nut body 1, and a middle deflector (circulation device) 30 and an end deflector 110 assembled to the nut body 1.

[0042] The nut body 1 is a cylindrical part made of steel. A spiral inner raceway surface 3 is provided on an inner circumferential surface 2 of the nut body 1. A spiral raceway 106 is formed between the inner raceway surface 3 and the outer raceway surface 102a. A plurality of balls 103 are arranged on this raceway 106. When the nut 101 rotates, the balls 103 roll on the inner raceway surface 3 and the outer raceway surface 102a and move in a spiral direction along the raceway 106.

[0043] A first accommodating portion (accommodating portion) 5 recessed radially inward from the outer circumferential surface 4 of the nut body 1 is provided near the end in the second axial direction X2 on the outer circumferential surface 4 of the nut body 1. A second accommodating portion 7 recessed in the second axial direction X2 is provided on an end face 6 of the nut body 1 in the first axial direction X1. The nut body 1 also has a return passage 8 that penetrates in the axial direction and connects the first accommodating portion 5 and the second accommodating portion 7. The middle deflector 30 is accommodated in the first accommodating portion 5. The end deflector 110 is accommodated in the second accommodating portion 7.

[0044] When the ball screw device 100 is driven, the ball 103 that has moved along the raceway 106 in the second axial direction X2 is picked up by the middle deflector 30 and guided to the return path 8. The ball 103 rolls along the return path 8 in the first axial direction X1 and enters the inside of the end deflector 110. The end deflector 110 then circulates the ball 103 to the end of the raceway 106 in the first axial direction X1. Furthermore, when the rotation direction of the nut 101 is reversed, the end deflector 110 scoops up the ball 103 from the raceway 106, and the middle deflector 30 circulates the ball 103 in the rolling path. This allows the ball 103 to continue rolling along the raceway 106.

[0045] In this embodiment, the middle deflector 30 and the end deflector 110 are provided as two circulation components, but in the present disclosure, both may be middle deflectors (circulation components). Next, the nut body 1 and the middle deflector 30 will be described in detail.

[0046] Fig. 3A is a cross-sectional view of the nut body taken along line III-III in Fig. 1, and the cross section is viewed from the direction of the arrow. As shown in Fig. 3A, the nut body 1 has a first accommodating portion 5, a seating surface 10 forming the bottom surface of the first accommodating portion 5, a through-hole 17 penetrating the seating surface 10, and a pair of side surfaces 20 (only one of which is shown in Fig. 3A) arranged on both axial sides of the first accommodating portion 5.

[0047] The first accommodating portion 5 is a space that is bow-shaped when viewed from the axial direction. The bow shape is a shape that is formed by combining an arc portion that overlaps with the outer peripheral surface 4 of the nut body 1 and a straight portion (a straight portion connecting both ends of the arc portion) that overlaps with the seating surface 10 when viewed from the axial direction.

[0048] The seating surface 10 is a surface against which the middle deflector 30 abuts (seats). When viewed from the axial direction, the seating surface 10 is a plane perpendicular to an imaginary line K1 extending radially from the axis O. Hereinafter, the direction in which the seating surface 10 extends when viewed from the axial direction (a direction perpendicular to the imaginary line K1 and the axial direction) will be referred to as the seating surface direction. Meanwhile, the direction parallel to the imaginary line K1 (a direction perpendicular to the seating surface) will be referred to as the vertical direction. Among the vertical directions, the direction in which the seating surface 10 faces will be referred to as the first vertical direction Z1. The opposite direction to the first vertical direction Z1 will be referred to as the second vertical direction Z2. In this embodiment, the seating surface 10 (first housing portion 5) extends in a direction perpendicular to the axis O when viewed from the outer periphery (see FIG. 4).

[0049] The through hole 17 extends vertically and penetrates the seat 10 and the inner peripheral surface 2 of the nut body 1. The through hole 17 also penetrates the center of the seat 10 in the seat direction. Therefore, the seat 10 is divided into a first seat 11 that is located on one side of the through hole 17 in the seat direction, and a second seat 12 that is located on the other side of the through hole 17 in the seat direction. Hereinafter, with regard to the seat direction, the direction in which the first seat 11 is located as viewed from the through hole 17 will be referred to as the first seat direction Y1. Furthermore, the direction opposite to the first seat direction Y1 will be referred to as the second seat direction Y2.

[0050] FIG. 3B is a view from the direction of arrow IIIB in FIG. 3A. As shown in FIG. 3B, the inner circumferential surface 18 of the through hole 17 has a side surface 18a disposed in the second bearing surface direction Y2 relative to the through hole 17. A notch 18b is formed in the side surface 18a. An edge 18c of the inner circumferential raceway surface 3 cut out by the through hole 17 is formed in the first vertical direction Z1 of the notch 18b. The edge 18c also serves as a corner where the side surface 18a and the inner circumferential raceway surface 3 intersect. The edge 18c serves as an entrance and exit for the inner circumferential raceway surface 3 when the ball 103 moves from the raceway 106 to the middle deflector 30. Furthermore, the edge 18c in this embodiment is chamfered. This allows for smooth transfer of the ball 103. Note that the present disclosure also allows for the edge 18c to be unchamfered.

[0051] 4 is a side view seen from the direction of arrow IV in FIG. 3A. As shown in FIG. 4, the through hole 17 has a rectangular shape when seen from the first vertical direction Z1. The through hole 17 penetrates the center of the seat 10 in the axial direction. The axial length L1 of the through hole 17 is shorter than the axial length L2 of the seat 10. Therefore, the seat 10 has extended seat surfaces 13 that form the edge portions 17a of the through hole 17 and are adjacent to both sides of the through hole 17 in the axial direction. Note that, although the four corners of the through hole 17 in this embodiment are right-angled, they may also be rounded corners. The through hole 17 is not limited to a rectangular shape.

[0052] The expandable seat 13 has a first expandable seat 14 arranged in a first axial direction X1 relative to the through hole 17, and a second expandable seat 15 arranged in a second axial direction X2 relative to the through hole 17. The first expandable seat 14 and the second expandable seat 15 each extend in the seat direction, and both ends are connected to the first seat 11 and the second seat 12.

[0053] The extended seating surface 13 does not need to be continuous in the seating direction as in the embodiment, as long as the middle deflector 30 can abut (sit on) it. Therefore, the present disclosure may also be an extended seating surface in which a portion in the seating direction is cut out and is not continuous in the seating direction.

[0054] As shown in FIG. 4 , the pair of side surfaces 20 have a first side surface 20a disposed in a first axial direction X1 relative to the seat surface 10 and a second side surface 20b disposed in a second axial direction X2 relative to the seat surface 10. The first side surface 20a and the second side surface 20b face each other in the axial direction. Details of the pair of side surfaces 20 will be described below, but technical content common to both the first side surface 20a and the second side surface 20b will be mainly described as "side surface 20." Technical content provided on the first side surface 20a or the second side surface 20b will be mainly described separately.

[0055] As shown in Fig. 3A, the side surface 20 is arch-shaped. Therefore, the side surface 20 has an arc-shaped outer peripheral edge portion 21. The side surface 20 is provided with a recess 22 that is recessed in the axial direction from the side surface 20 and extends toward the bearing surface. One end of the recess 22 extends to the outer peripheral edge portion 21. Therefore, the recess 22 opens toward the first accommodating portion 5 and toward the outer peripheral side of the nut body 1.

[0056] Two recesses 22 are provided on one side surface 20. One of the two recesses 22 is positioned further from the through hole 17 in the first seating direction Y1, and opens in the first seating direction Y1 by cutting out the outer peripheral edge portion 21. The other of the two recesses 22 is positioned further from the through hole 17 in the second seating direction Y2, and opens in the second seating direction Y2 by cutting out the outer peripheral edge portion 21. In other words, the two recesses 22 provided on one side surface 20 are separated into one and the other in the seating direction by the through hole 17 as a boundary.

[0057] 5 is a side view seen from the direction of arrow V in FIG. 3A. The recess 22 is spaced apart from the seating surface 10 in the first vertical direction Z1. The cross-sectional shape of the recess 22 is triangular. Therefore, the inner surface of the recess 22 has a first inclined surface 23 that moves away from the first storage portion 5 in the first vertical direction Z1, and a second inclined surface 24 that moves closer to the first storage portion 5 in the first vertical direction Z1.

[0058] Hereinafter, the recess 22 provided on the first side surface 20a will be referred to as the first recess 22a, and the recess 22 provided on the second side surface 20b will be referred to as the second recess 22b. The first inclined surface 23 and the second inclined surface 24 provided on the first recess 22a will be referred to as the first inclined surface 23a and the second inclined surface 24a. The first inclined surface 23 and the second inclined surface 24 provided on the second recess 22b will be referred to as the first inclined surface 23b and the second inclined surface 24b.

[0059] 3A, the first side surface 20a is provided with an opening 8a which is an entrance / exit for the return path 8, and a positioning hole 26. The positioning hole 26 is a hole recessed from the first side surface 20a in the first axial direction X1. The positioning hole 26 also opens toward the outer peripheral surface 4 of the nut body 1. The inner surface of the positioning hole 26 has a pair of opposing surfaces 26a which sandwich the positioning hole 26 from the seating surface direction, a side surface 26b which is disposed in the first axial direction X1 relative to the positioning hole 26, and a bottom surface 26c which is disposed in the second vertical direction Z2 relative to the positioning hole 26. Next, the middle deflector 30 will be described.

[0060] FIG. 6 is an enlarged view of the middle deflector and its surroundings in FIG. 1. The middle deflector 30 is a metal component manufactured by metal powder injection molding, cutting, forging, or other methods. As shown in FIG. 6, the middle deflector 30 is disposed in the first housing 5. Therefore, when viewed from the outer periphery, the middle deflector 30 extends in the same direction as the first housing 5 (seat 10) (a direction perpendicular to the axis O; see FIG. 4). The middle deflector 30 includes a deflector body (circulation component body) 31, an arm 50 protruding from the deflector body 31 toward the seat, a rib 60 protruding from the arm 50 in the first vertical direction Z1, and a crimped portion 70 formed by crimping a portion of the rib 60. The crimped portion 70 is generated by crimping the rib 60 when the middle deflector 30 is attached to the nut body 1. Therefore, the crimped portion 70 is not shown in the drawings showing the middle deflector 30 before assembly.

[0061] Fig. 7 is a cross-sectional view taken along line VII-VII in Fig. 6. As shown in Fig. 7, a ball passage 34 through which the ball 103 passes is provided inside the deflector body 31. The deflector body 31 also has a main body portion 32 disposed in the first housing portion 5 and a scooping portion 33 disposed in the through-hole 17. A second opening 37 connecting the ball passage 34 and the return path 8 is provided in the main body portion 32. A first opening 33a connecting the ball passage 34 and the track 106 is provided in the scooping portion 33.

[0062] The ball passage 34 extends along a tangent line (hereinafter referred to as imaginary line K2) to an imaginary circle C formed by connecting the centers of the balls 103 on the raceway 106. The portion of the first opening 33a on the outer periphery side of the imaginary line K2 is continuous with a notch 18b provided in the side surface 18a. The scooping portion 33 is provided with a tongue 35 that scoops up the ball 103 from the raceway 106 in the tangential direction.

[0063] The outer peripheral surface 32a of the main body 32 in the first vertical direction Z1 is arc-shaped. When viewed from the axial direction, the outer peripheral surface 32a of the main body 32 overlaps with the outer peripheral surface 4 of the nut body 1. In other words, the distance from the axis O to the outer peripheral surface 32a of the middle deflector 30 is the same as the outer diameter of the nut body 1. Therefore, the middle deflector 30 does not protrude from the first accommodating portion 5.

[0064] Fig. 8 is a perspective view of the middle deflector of embodiment 1 before crimping, viewed from a first vertical direction. Fig. 9 is a perspective view of the middle deflector of embodiment 1 before crimping, viewed from a second vertical direction. Fig. 10 is a cross-sectional view taken along line XX in Fig. 6. Fig. 11 is a cross-sectional view taken along line XI-XI in Fig. 6. Fig. 12 is a side view taken along arrow XII in Fig. 6.

[0065] As shown in FIGS. 8 and 9, the main body 32 has a first opposing surface 36 as a side surface facing the first axial direction X1. The first opposing surface 36 faces the first side surface 20a. A second opening 37 is provided in the first opposing surface 36. As shown in FIG. 10, the second opening 37 is axially continuous (adjacent) with the opening 8a of the return path 8. This allows the ball 103 to move from the ball passage 34 to the return path 8, or from the return path 8 to the ball passage 34. To facilitate the transfer of the ball 103, the opening 8a and the second opening 37 are round-chamfered. Note that, in the present disclosure, the chamfering of the opening 8a and the second opening 37 may be square-chamfered instead of round-chamfered.

[0066] As shown in Figures 8 and 9, the first opposing surface 36 is provided with a positioning protrusion 38 that protrudes in the first axial direction X1. The positioning protrusion 38 has a rectangular prism shape. As shown in Figure 6, the positioning protrusion 38 is inserted into the positioning hole 26. The positioning protrusion 38 abuts against a pair of opposing surfaces 26a of the positioning hole 26. This prevents the middle deflector 30 from shifting in the seating surface direction from a predetermined assembly position.

[0067] 11, the tip surface 38a of the positioning protrusion 38 is spaced apart from the side surface 26b of the positioning hole 26. In other words, a gap S10 is formed between the tip surface 38a and the side surface 26b. As a result, if the positioning protrusion 38 is manufactured to protrude more than a predetermined amount, the manufacturing error is absorbed by the gap S10. In other words, it is possible to prevent the positioning protrusion 38 from hitting the side surface 26b of the positioning hole 26, which would cause the first side surface 20a and the first opposing surface 36 to separate from each other.

[0068] Note that the separation between the first side surface 20a and the first opposing surface 36 leads to separation between the opening 8a of the return path 8 and the second opening 37 of the ball passage 34, preventing smooth delivery of the ball 103. Therefore, to ensure smooth delivery of the ball 103, it is desirable that the first side surface 20a and the first opposing surface 36 are in contact with each other.

[0069] Furthermore, the bottom surface 38b of the positioning protrusion 38 is spaced apart from the bottom surface 26c of the positioning hole 26. That is, a gap S11 is formed between the bottom surfaces 38b and 26c. With this, if the positioning protrusion 38 is manufactured so that its vertical thickness is greater than a predetermined amount, the manufacturing error is absorbed by the gap S11. This prevents the positioning protrusion 38 from contacting (catching on) the bottom surface 26d of the positioning hole 26, preventing the middle deflector 30 from seating (contacting) on ​​the seating surface 10.

[0070] Additionally, the positioning protrusion 38 and the positioning hole 26 are provided only in the first axial direction X1 with respect to the middle deflector 30. Therefore, when the middle deflector 30 is disposed in the first accommodating section 5, it is possible to avoid the positioning protrusion 38 being erroneously disposed facing the second axial direction X2 (with the second opening 37 facing the second axial direction).

[0071] 7, the length L3 of the main body 32 in the seating direction is longer than the length L4 of the scooping portion 33 in the seating direction. Therefore, the main body 32 has a seating surface 40 that faces the second vertical direction Z2 and abuts (sits on) against the seating surface 10. The seating surface 40 also has a first seating surface 41 that abuts against the first seating surface 11 and a second seating surface 42 that abuts against the second seating surface 12. In other words, the middle deflector 30 has seating surfaces 40 on both sides of the through-hole 17 in the seating direction.

[0072] 11, the axial length L5 of the main body 32 is longer than the axial length L6 of the scooping portion 33. Therefore, the seating surface 40 has an extended seating surface 43 arranged axially relative to the scooping portion 33. The extended seating surface 43 has a first extended seating surface 44 arranged in the first axial direction X1 relative to the scooping portion 33 and a second extended seating surface 45 arranged in the second axial direction X2 relative to the scooping portion 33. The first extended seating surface 44 abuts against the first extended seating surface 14 of the seating surface 10. The second extended seating surface 45 abuts against the second extended seating surface 15.

[0073] As shown in FIG. 11 , the main body 32 has a second opposing surface 46 as a side surface facing the second axial direction X2. The second opposing surface 46 faces the second side surface 20b. The second opposing surface 46 is flat. Due to tolerances, the axial length L5 of the main body 32 is slightly smaller than the axial width L7 of the first housing portion 5. That is, a small gap (not shown) is generated between the first side surface 20a and the first opposing surface 36, or between the second side surface 20b and the second opposing surface 46, or between both. This allows the middle deflector 30 to be securely housed in the first housing portion 5.

[0074] 7, the arm 50 has a first arm 51 extending from the main body 32 in the first seating direction Y1 and a second arm 52 extending from the main body 32 in the second seating direction Y2. The first arm 51 has a first arm seating surface 53 as a side surface facing the second vertical direction Z2. The second arm 52 has a second arm seating surface 54 as a side surface facing the second vertical direction Z2. The first arm seating surface 53 abuts against the first seating surface 11. The second arm seating surface 54 abuts against the second seating surface 12.

[0075] Next, the ribs 60 will be described. As shown in Fig. 6, the ribs 60 are provided on both the first arm portion 51 and the second arm portion 52. Therefore, in the following description, the ribs 60 provided on the second arm portion 52 will be described, and a description of the ribs 60 on the first arm portion 51 will be omitted.

[0076] 8, the rib 60 is a protrusion that protrudes from a plane 55 of the second arm portion 52 facing the first vertical direction Z1 and extends linearly in the seating direction. The length of the rib 60 in the seating direction is the same as that of the second arm portion 52. An end of the rib 60 in the first seating direction Y1 is connected to the main body portion 32 (deflector main body 31). Hereinafter, the end of the rib 60 that is connected to the main body portion 32 will be referred to as a base portion 60a, and the opposite end will be referred to as a tip portion 60b.

[0077] The rib 60 has a first rib 61 extending along the edge of the flat surface 55 in the first axis direction X1 and a second rib 62 extending along the edge of the flat surface 55 in the second axis direction X2. The first rib 61 extends along the first side surface 20a and is adjacent to the first recess 22a in the axial direction (see FIG. 17B). The second rib 62 extends along the second side surface 20b and is adjacent to the second recess 22b in the axial direction (see FIG. 17B).

[0078] 6, the crimped portion 70 is formed by crimping the rib 60 extending along the side surface 20 to the side surface 20. The crimped portion 70 is provided only at the tip end portion 60b of the rib 60. The crimped portion 70 has a first crimped portion 71 provided on the first rib 61 and a second crimped portion 72 provided on the second rib 62.

[0079] 12, the first crimped portion 71 fits into the first recess 22a. The first crimped portion 71 has a shape that follows the inner surface of the first recess 22a. Specifically, the first crimped portion 71 is inclined toward the first axial direction X1 as it extends from the plane 55 in the first vertical direction Z1. A side surface 71a of the first crimped portion 71 facing the first axial direction X1 abuts against the first inclined surface 23a. An end surface 71b of the first crimped portion 71 facing the first vertical direction Z1 abuts against the second inclined surface 24a.

[0080] The second crimped portion 72 fits into the second recess 22b. The second crimped portion 72 has a shape that follows the inner surface of the second recess 22b. Specifically, the second crimped portion 72 is inclined so as to be located in the second axial direction X2 as it extends from the plane 55 in the first vertical direction Z1. A side surface 72a of the second crimped portion 72 facing the second axial direction X2 abuts against the first inclined surface 23b. An end surface 72b of the second crimped portion 72 facing the first vertical direction Z1 abuts against the second inclined surface 24b. As described above, the first crimped portion 71 and the second crimped portion 72 are inclined so as to be axially spaced apart from each other as they extend in the first vertical direction Z1.

[0081] As shown in FIGS. 8 and 9, the middle deflector 30 of this embodiment is formed by assembling two components (an inner peripheral component 81 and an outer peripheral component 82) separated along a dividing surface 80. As shown in FIG. 7, the dividing surface 80 extends in the axial direction. When viewed from the axial direction, the dividing surface 80 is parallel to a tangent to the imaginary circle C (see imaginary line K2). Specifically, the dividing surface 80 of this embodiment overlaps the edge of the outer peripheral side of the ball passage 34. Therefore, the dividing surface 80 is inclined toward the first vertical direction Z1 as it extends in the first seating surface direction Y1. Hereinafter, of the two components constituting the middle deflector 30, the one located on the inner peripheral side of the dividing surface 80 will be referred to as the inner peripheral component 81, and the one located on the outer peripheral side of the dividing surface 80 will be referred to as the outer peripheral component 82.

[0082] The components of the middle deflector 30 are divided into an inner part 81 and an outer part 82, with a dividing surface 80 as the boundary line. In this embodiment, the inner part 81 has a first arm portion 51, a tongue 35, and an extended seating surface 43 (see FIG. 9 ). On the other hand, the outer part 82 has a second arm portion 52. Hereinafter, the end face of the inner part 81 extending along the dividing surface 80 will be referred to as an inner part dividing surface 83. Also, the end face of the outer part 82 extending along the dividing surface 80 will be referred to as an outer part dividing surface 84.

[0083] Fig. 13 is a perspective view of the inner part of the first embodiment. As shown in Fig. 13, an inner divided surface 83 of the inner part 81 is provided with a passage groove surface 85 that is a C-shaped or U-shaped concave surface recessed in the second vertical direction Z2. The internal space of the passage groove surface 85 serves as the ball passage 34. The ball passage 34 has a straight portion 34a that extends linearly along the imaginary line K2 and a curved portion 34b that curves from the straight portion 34a in the axial direction. Thus, the passage groove surface 85 also has a straight portion and a curved portion corresponding to the ball passage 34.

[0084] The passage groove surface 85 has an inner peripheral rolling surface 85a disposed on the inner peripheral side of the ball passage 34 (imaginary line K2), and a pair of side surfaces 85b that sandwich the ball passage 34 (imaginary line K2). Although not particularly shown, the inner peripheral rolling surface 85a has a gothic arc shape or a circular arc shape.

[0085] The inner peripheral part 81 has a side surface 81a facing the first axial direction X1 and an end surface 81b facing the second seating surface direction Y2. The side surface 81a is a part of the first opposing surface 36. One end 85c in the longitudinal direction along which the passage groove surface 85 extends reaches the first opposing surface 36. As a result, a second opening 37 is provided in the first opposing surface 36.

[0086] The other longitudinal end 85d of the passage groove surface 85 reaches the end face 81b. As a result, the first opening 33a is provided at the end face 81b. The first opening 33a is also cut out in a portion other than the end face 81b (see FIG. 14). Therefore, the portion provided at the end face 81b is a part of the first opening 33a that is located on the outer circumferential side of the imaginary line K2.

[0087] Fig. 14 is an enlarged view of the vicinity of the first opening shown in Fig. 7. As shown in Fig. 14, the end face 81b faces the side face 18a of the inner circumferential surface 18 of the through hole 17. Although not shown, a small gap is provided between the end face 81b and the side face 18a. The portion of the first opening 33a that is provided on the end face 81b is continuous with the notch 18b in the side face 18a. This allows the ball passage 34 to be continuous with the notch 18b (inner circumferential raceway surface 3).

[0088] Fig. 15 is a perspective view of the outer periphery side part of embodiment 1. As shown in Fig. 15, the outer periphery side divided surface 84 of the outer periphery side part 82 is flat. In addition, a protrusion 89 that protrudes toward the inner periphery side part 81 (in the second vertical direction Z2) is provided on a part of the outer periphery side divided surface 84.

[0089] 16A is a view seen from the direction of arrow XVIA in FIG. 14. As shown in FIG. 16A, the surface of the protrusion 89 in the second vertical direction Z2 forms a groove surface 89a. While the groove surface 89a has a Gothic arc shape in this embodiment, it may have a circular arc shape in the present disclosure. The protrusion 89 is inserted into the passage groove surface 85 of the inner peripheral side part 81. Both side surfaces 89c of the protrusion 89 abut against a pair of side surfaces 85b of the passage groove surface 85. This makes it less likely that the inner peripheral side part 81 and the outer peripheral side part 82 will be joined together with misalignment in the axial direction.

[0090] As shown in FIG. 14, the groove surface 89a is located on the outer periphery side of the imaginary line K2 and serves as a wall surface covering the outer periphery side of the ball passage 34. The protrusion 89 is located at the other longitudinal end 85d of the passage groove surface 85. The groove surface 89a forms the outer periphery rolling surface 86 closest to the first opening 33a. An edge 89b of the groove surface 89a (a portion of the groove surface 89a located at the end in the second seating surface direction Y2) is continuous with (adjacent to) the edge 18c of the inner circumferential raceway surface 3. As a result, the ball 103 traveling from the raceway 106 toward the ball passage 34 rolls on the groove surface 89a immediately after passing through the first opening 33a.

[0091] FIG. 16B shows a state in which the middle deflector is displaced axially from the state shown in FIG. 16A. FIG. 16C shows a state in which the middle deflector is displaced vertically from the state shown in FIG. 16A. For clarity, the chamfered portion of the edge 18c of the inner raceway surface 3 is not shown in FIGS. 16B and 16C. As shown in FIG. 16A, the groove shape of the edge 89b of the groove surface 89a is larger than the groove shape of the edge 18c of the inner raceway surface 3. In other words, the edge 89b of the groove surface 89a has a larger radius of curvature than the edge 18c of the inner raceway surface 3. Therefore, as shown in FIG. 16B, even if the middle deflector 30 is displaced axially, the edge 89b of the groove surface 89a does not enter inside the edge 18c of the inner raceway surface 3. 16C, even if the middle deflector 30 is displaced vertically, the edge 89b of the groove surface 89a does not enter the inside of the edge 18c of the inner circumferential raceway surface 3. This prevents the ball 103 from coming into contact with the edge 89b of the groove surface 89a, which would hinder the transfer of the ball 103. The edge 89b of the groove surface 89a is chamfered (see FIG. 15). This allows the ball 103 to be transferred smoothly. However, the present disclosure also allows the edge 89b to be non-chamfered.

[0092] As shown in FIG. 16A, the outer peripheral rolling surface 86 is covered by a portion of the outer peripheral divided surface 84 except for a portion (groove surface 89a) of the ball passage 34 near the first opening 33a. Hereinafter, the portion of the outer peripheral divided surface 84 that covers the outer peripheral side of the ball passage 34 (see the portion between the two dashed lines in FIG. 15) will be referred to as the plane 86a. From the above, the outer peripheral rolling surface 86 that covers the ball passage 34 from the outer peripheral side is composed of the plane 86a and the groove surface 89a. The groove surface 89a protrudes less in the second vertical direction from the edge 89b toward the first seating surface direction Y1. Therefore, there is no step between the groove surface 89a and the plane 86a, allowing the balls to roll smoothly.

[0093] The inner peripheral side part 81 and the outer peripheral side part 82 are manufactured separately. Then, the inner peripheral side divided surface 83 and the outer peripheral side divided surface 84 are joined together to integrate the inner peripheral side part 81 and the outer peripheral side part 82. Examples of joining methods include thermal welding and adhesive bonding.

[0094] 7, an end portion of the divided surface 80 in the first seating surface direction Y1 extends in the first vertical direction Z1. In other words, a stepped surface 87 extending in the first vertical direction Z1 and facing the second seating surface direction is provided at an end portion of the inner divided surface 83 in the first seating surface direction Y1. On the other hand, an end surface 88 extending in the first vertical direction Z1 and facing the first seating surface direction Y1 is provided at an end portion of the outer divided surface 84 in the first seating surface direction Y1. The stepped surface 87 and the end surface 88 abut against each other. Therefore, when the inner divided surface 81 and the outer divided surface 82 are joined together, they are prevented from being misaligned in the seating surface direction.

[0095] Next, a description will be given of an assembly method S for assembling the middle deflector 30 to the nut body 1. The assembly method S includes a preparation step S1 and a crimping step S2.

[0096] FIG. 17A is a perspective view showing a preparation step of the assembly method of the first embodiment. The preparation step S1 is a step of seating the middle deflector 30 on the seating surface 10 of the nut body 1. Specifically, as shown in FIG. 17A, first, the middle deflector 30 is placed in the first vertical direction Z1 of the first housing portion 5 of the nut body 1. The middle deflector 30 is oriented so that the seating surface 40 (not shown in FIG. 17A) and the scooping portion 33 face toward the first housing portion 5. The positioning protrusion 38 of the middle deflector 30 points in the first axial direction X1. Note that the middle deflector 30 of this embodiment has the positioning protrusion 38. However, if the middle deflector 30 does not have the positioning protrusion 38, it is confirmed that the second opening 37 faces the first axial direction X1 instead of the positioning protrusion 38.

[0097] Next, the middle deflector 30 is moved in the second vertical direction Z2 (see arrow A1 in FIG. 17A ) and inserted into the first housing portion 5. The position of the middle deflector 30 is also adjusted in the axial and seating directions so that the scooping portion 33 is inserted into the through hole 17 and the positioning protrusion 38 is inserted into the positioning hole 26. After the scooping portion is inserted into the through hole 17 and the positioning protrusion 38 is inserted into the positioning hole 26, the middle deflector 30 is further moved in the second vertical direction Z2, and the seating surface 40 of the middle deflector 30 abuts against the seating surface 10. As a result, the middle deflector 30 is seated on the seating surface 10, and the preparation step S1 is completed.

[0098] 17B is a side view of the state before crimping, as viewed from the second bearing surface direction, in the crimping step of the assembly method of Embodiment 1. The crimping step S2 is a step of crimping the rib 60 with a jig 120. As shown in FIG. 17B, the amount of axial gap between the first rib 61 and the second rib 62 is L8.

[0099] The jig 120 includes a head 121 inserted between the first rib 61 and the second rib 62, and a grip 122 disposed on the first vertical direction Z1 of the head 121. A tip 123 is provided on the end of the head 121 in the second vertical direction Z2. The axial width of the tip 123 narrows toward the second vertical direction Z2.

[0100] The tip portion 123 has a tip surface 124 facing the second vertical direction Z2, a first pressing surface 125 facing the first axial direction X1, and a second pressing surface 126 facing the second axial direction X2. The axial width L9 of the tip surface 124 is smaller than the separation distance L8 between the first rib 61 and the second rib 62.

[0101] The axial width of the first pressing surface 125 and the second pressing surface 126 gradually increases toward the first vertical direction Z1, reaching a maximum of L10. The maximum axial width L10 of the first pressing surface 125 and the second pressing surface 126 is greater than the separation distance L8 between the first rib 61 and the second rib 62.

[0102] In the method of crimping using the jig 120, first, the tip portion 123 of the jig 120 is inserted between the first rib 61 and the second rib 62 from the first vertical direction Z1 (see arrow A2 in FIG. 17B). As a result, although not particularly shown, the tip surface 124 is inserted between the first rib 61 and the second rib 62, the first pressing surface 125 abuts against the first rib 61, and the second pressing surface 126 abuts against the second rib 62. In addition, the tip surface 124 is in a state of being lifted (separated) from the flat surface 55 of the arm portion 50.

[0103] 17C is a side view of the state after crimping, as viewed from the second bearing surface direction, in the crimping step of the assembling method of Embodiment 1. Then, as shown in FIG. 17C, the jig 120 is pressed in the second vertical direction Z2 until the tip end surface 124 abuts against the flat surface 55. As a result, the first rib 61 is crimped in the first axial direction X1 by the first pressing surface 125. Furthermore, the second rib 62 is crimped in the second axial direction X2 by the second pressing surface 126.

[0104] The crimped portion of the first rib 61 is inclined toward the first recess 22a disposed in the first axial direction X1, forming the first crimped portion 71. The first crimped portion 71 is compressed in the axial direction between the inner surface of the first recess 22a and the first pressing surface 125, and assumes a shape that conforms to the inner surface of the first recess 22a. That is, the first crimped portion 71 has a side surface 71a that extends along the first inclined surface 23a and an end surface 71b that extends along the second inclined surface 24a.

[0105] Similarly, the crimped portion of the second rib 62 inclines toward the second recess 22b disposed in the second axial direction X2, forming the second crimped portion 72. The second crimped portion 72 is compressed in the axial direction between the inner surface of the second recess 22b and the second pressing surface 126, and assumes a shape that conforms to the inner surface of the first recess 22a. That is, the second crimped portion 72 has a side surface 72a extending along the first inclined surface 23b and an end surface 72b extending along the second inclined surface 24b.

[0106] Then, once the first crimped portion 71 and the second crimped portion 72 are formed, the jig 120 is removed in the first vertical direction Z1, and the crimping step S2 is completed.

[0107] 17D is a plan view of the crimping step of embodiment 1 as viewed from the first vertical direction. As shown in FIG. 17D, in the crimping step S2, the portion crimped by the jig 120 is not the entire rib 60 but the tip end 60b of the rib 60. This is because the base 60a of the rib 60 is connected to the deflector body 31 and is therefore less likely to tilt. Furthermore, if the base 60a of the rib 60 is crimped forcibly, the deflector body 31 may be deformed.

[0108] When the tip 60b of the rib 60 is crimped, the first crimped portion 71 and the second crimped portion 72 form a generally V-shape when viewed from the first vertical direction Z1. That is, the first crimped portion 71 and the second crimped portion 72 are inclined in the axial direction by an increasing amount toward the tip 60b. Note that not only the crimped tip 60b but also the central portion of the rib 60 in the seating surface direction is slightly inclined in the axial direction.

[0109] Meanwhile, during the crimping operation, a load acts on the middle deflector 30 in a direction in which the rib 60 escapes from the load from the jig 120 (see arrows A3 and A4). More specifically, when the rib 60 of the first arm portion 51 is crimped, a load acts on the middle deflector 30 in the second seating direction Y2 (see arrow A3). On the other hand, when the rib 60 of the second arm portion 52 is crimped, a load acts on the middle deflector 30 in the first seating direction Y1 (see arrow A4). Therefore, the positioning protrusion 38 may be deformed, and the middle deflector 30 may become misaligned.

[0110] Fig. 17E is a perspective view showing a state in which two jigs are used for crimping in the crimping step of embodiment 1. Therefore, in the crimping step S2, as shown in Fig. 17E, it is desirable to prepare two jigs 120 and crimp the rib 60 of the first arm portion 51 and the rib 60 of the second arm portion 52 simultaneously. In this way, the load acting on the first arm portion 51 (see arrow A3 in Fig. 17D) and the load acting on the second arm portion 52 (see arrow A4 in Fig. 17D) are opposed to each other and offset each other. This prevents deformation of the positioning protrusion 38.

[0111] Furthermore, the inner peripheral side component 81 having the first arm portion 51 and the outer peripheral side component 82 having the second arm portion 52 are in contact with each other at the step surface 87 and the end surface 88 (see FIG. 7). Therefore, even if the first arm portion 51 and the second arm portion 52 are simultaneously crimped with the two jigs 120, the joining between the inner peripheral side component 81 and the outer peripheral side component 82 will not be released.

[0112] Next, the effects of the ball screw device 100 of the first embodiment will be described. In the first embodiment, when a load acts on the middle deflector 30 in the first vertical direction Z1, the crimped portion 70 gets caught in the recess 22. Therefore, the middle deflector 30 does not shift in position in the first vertical direction Z1. In other words, the middle deflector 30 does not come off the nut body 1. Furthermore, in this embodiment, the base 60a of the rib 60 is connected to the deflector body 31, and the rib 60 and the crimped portion 70 have high rigidity and are unlikely to tilt. Therefore, even if a load acts on the middle deflector 30 in the first vertical direction Z1 and the crimped portion 70 gets caught on the second inclined surface 24, the crimped portion 70 is unlikely to deform (and is even less likely to tilt). This also prevents the middle deflector 30 from shifting in position in the first vertical direction Z1.

[0113] Furthermore, the crimping portion 70 is provided on each of the first arm portion 51 and the second arm portion 52. That is, according to the first embodiment, there are more crimping points (crimping portions 70) than when the crimping portion 70 is provided on only one of the two arm portions 50. Therefore, the middle deflector 30 is more securely prevented from coming off. Furthermore, one of the two arm portions 50 is provided on the inner peripheral side component 81, and the other is provided on the outer peripheral side component 82. Therefore, even if the connection between the inner peripheral side component 81 and the outer peripheral side component 82 is released, the inner peripheral side component 81 and the outer peripheral side component 82 will not come off the nut body 1.

[0114] Furthermore, the crimping portion 70 has a first crimping portion 71 and a second crimping portion 72 for each arm portion 50. That is, there are more crimping points (crimping portions 70) than when one crimping portion 70 is provided for each arm portion 50. This makes it possible to more firmly prevent the middle deflector 30 from coming off.

[0115] If the middle deflector 30 abuts against the seat 10 only on one side of the through-hole 17 in the axial direction of the seating surface, the deflector body 31 may fall into the through-hole 17, causing the middle deflector 30 to tilt. As a result, the tongue 35 may become misaligned, preventing the ball 103 from being smoothly scooped up. On the other hand, the middle deflector 30 of this embodiment has, as the seating surface 40, a first seating surface 41 and a first arm seating surface 53 disposed in the first seating surface direction Y with respect to the through-hole 17, and a second seating surface 42 and a second arm seating surface 54 disposed in the second seating surface direction Y2 with respect to the through-hole 17. In other words, the middle deflector 30 has the seating surfaces 40 on both sides of the through-hole 17 in the seating surface direction. Therefore, the deflector body 31 does not fall into the through-hole 17, and the posture of the middle deflector 30 is stable. As a result, the ball 103 can be picked up smoothly.

[0116] Furthermore, the middle deflector 30 has an extended seating surface 43 that abuts against the extended seating surface 13 of the seat 10. This further stabilizes the posture of the middle deflector 30. Furthermore, the extended seating surface 43 is provided on the inner peripheral part 81. Therefore, even if the joint between the inner peripheral part 81 and the outer peripheral part 82 is released, the extended seating surface 43 catches on the extended seating surface 13, preventing the inner peripheral part 81 from falling into the through hole 17.

[0117] Furthermore, the dividing plane 80 between the inner peripheral part 81 and the outer peripheral part 82 extends in the axial direction along the ball passage 34. If the dividing plane were perpendicular to the axial direction (a plane extending both in the seating surface direction and perpendicularly), the tongue would be divided in the axial direction, resulting in a decrease in the strength of the tongue. In other words, in this embodiment, the ball passage 34 is cut in the axial direction, so that the inner peripheral part 81 is configured without dividing the tongue 35. As a result, the strength of the tongue 35 is maintained.

[0118] Furthermore, in this embodiment, near the first opening 33a, the edge 89b of the groove surface 89a and the edge 18c of the inner circumferential raceway surface 3 are adjacent to each other, and the ball 103 rolls continuously on the groove surface 89a and the inner circumferential raceway surface 3. In other words, it is possible to prevent the ball 103 from getting caught on the side surface 18a of the inner circumferential surface 18, preventing the ball 103 from moving smoothly. This allows the ball 103 to be smoothly transferred between the raceway 106 and the ball passage 34.

[0119] Furthermore, the sum of the curvatures of the groove surface 89a and the ball 103 is smaller than the sum of the curvatures of the flat surface 86a and the ball 103. In other words, the groove surface 89a increases the contact ellipse, and the surface pressure acting on the groove surface 89a decreases. This reduces wear and damage to the groove surface 89a.

[0120] Furthermore, in this embodiment, the outer peripheral rolling surface 86 is a flat surface 86a at the curved portion 34b of the ball passage 34 (see FIG. 13). If the outer peripheral rolling surface 86 were a grooved surface 89a instead of a flat surface 86a, the balls would move along the grooved surface, reducing the degree of freedom of their movement. On the other hand, in this embodiment, the flat surface 86a is the outer peripheral rolling surface 86, increasing the degree of freedom of the balls 103. This increases the space within the curved portion 34b in which the balls 103 can move, reducing the likelihood of the balls 103 becoming clogged. As a result, the balls 103 move smoothly through the curved portion 34b. Furthermore, the generation of contact noise caused by the balls 103 coming into contact with each other is also reduced.

[0121] As described above, the ball screw device 100 of the first embodiment includes a nut 101, a screw shaft 102 that penetrates the nut 101, and a plurality of balls 103 that are arranged between the nut 101 and the screw shaft 102. The nut 101 includes a cylindrical nut body 1 that is penetrated by the screw shaft 102, and a circulation part (middle deflector 30) that is assembled to the nut body 1. The nut body 1 has an inner circumferential raceway surface 3 that is provided on its inner circumferential surface 2 and faces an outer circumferential raceway surface 102a of the screw shaft 102, a housing portion (first housing portion 5) that is formed by recessing a portion of the outer circumferential surface 4 of the nut body 1, a seating surface 10 that forms the bottom surface of the housing portion, and a through hole 17 that penetrates the seating surface 10 and the inner circumferential surface 2 of the nut body 1 and cuts out a portion of the inner circumferential raceway surface 3. The circulation component (middle deflector 30) has a circulation component main body (deflector main body 31) disposed in the accommodation section and through-hole 17, and an arm portion 50 extending from the circulation component main body toward the seat surface 10 and abutting against the seat surface 10. The circulation component main body (deflector main body 31) has a first opening 33a that opens toward a raceway 106 between the outer circumferential raceway surface 102a and the inner circumferential raceway surface 3, and a ball passage 34 that extends from the first opening 33a along a tangent (imaginary line K2) to an imaginary circle C formed by connecting the centers of multiple balls 103 rolling on the raceway 106. The inner surface of the ball passage 34 has an inner circumferential rolling surface 85a disposed on the inner circumferential side of the tangent (imaginary line K2) and an outer circumferential rolling surface 86 disposed on the outer circumferential side of the tangent. At least a portion of the outer circumferential rolling surface 86 near the first opening 33a forms a groove surface 89a. The groove surface 89 a is continuous with the edge portion 18 c of the inner circumferential raceway surface 3 cut out by the through hole 17 .

[0122] According to the first embodiment, the balls 103 are smoothly transferred between the raceway 106 and the ball passage 34. Furthermore, the surface pressure acting on the outer circumferential rolling surface 86 (groove surface 89a) is reduced, and breakage and damage to the outer circumferential rolling surface 86 (groove surface 89a) is suppressed.

[0123] Furthermore, the ball passage 34 of the first embodiment has a curved portion 34b that changes the moving direction of the ball 103. The outer circumferential rolling surface 86 has a flat surface 86a at the curved portion 34b.

[0124] According to the first embodiment, the balls 103 move smoothly along the curved portion 34b, and the generation of contact noise caused by the balls 103 coming into contact with each other is also suppressed.

[0125] Furthermore, the groove shape of the edge portion 89b of the groove surface 89a in the first embodiment is larger than the groove shape of the inner circumferential raceway surface 3.

[0126] According to the first embodiment, the positional deviation of the middle deflector 30 is absorbed. This prevents the ball 103 from coming into contact with the edge 89b of the groove surface 89a, which would impair smooth delivery of the ball 103.

[0127] The circulation component body (deflector body 31) of the first embodiment has a second opening 37, which is an opening of the ball passage 34 and is provided on the opposite side to the first opening 33a. The second opening 37 is chamfered.

[0128] According to the first embodiment, the ball 103 can be smoothly transferred between the ball passage 34 and the return path 8.

[0129] The circulation component (middle deflector 30) of the first embodiment is formed by joining an inner peripheral component 81 and an outer peripheral component 82, which are separated by a separation surface 80 extending along the ball passage 34 when viewed from an axial direction parallel to the screw shaft 102. The groove surface 89a is provided in the outer peripheral component 82.

[0130] According to the first embodiment, the groove surface 89a can be formed more easily than when the groove surface 89a is formed in the inner peripheral side part 81. Therefore, the circulation part (middle deflector 30) can be manufactured more easily.

[0131] Moreover, in the first embodiment, the nut body 1 has a pair of side surfaces 20 that are arranged on both axial sides of the accommodation portion (first accommodation portion 5) and that face each other. The accommodation portion (first accommodation portion 5) is arch-shaped when viewed in the axial direction. The direction parallel to the seating surface 10 when viewed in the axial direction is the seating surface direction. The direction perpendicular to the seating surface 10 and in which the seating surface 10 faces is the first vertical direction Z1. The circulating part has a rib 60 that protrudes from the arm portion 50 in the first vertical direction Z1 and extends along the side surface 20 in the seating surface direction, and a crimped portion 70 formed by crimping at least a portion of the rib 60 toward the side surface 20. The pair of side surfaces 20 are provided with recesses 22 that are grooves that extend in the seating surface direction, face the rib 60 in the axial direction, and into which the crimped portion 70 fits.

[0132] According to the first embodiment, the crimped portion 70 is caught on the inner surface of the recess 22, and the circulation part (middle deflector 30) does not come off the nut body 1.

[0133] In the first embodiment, the through hole 17 penetrates through the center of the seat 10 in the seat direction. The seat 10 has a first seat 11 disposed on one side of the through hole 17 in the seat direction, and a second seat 12 disposed on the other side of the through hole 17 in the seat direction. The arm 50 has a first arm 51 extending from the circulation component main body (deflector main body 31) in one side of the seat direction and abutting against the first seat 11, and a second arm 52 extending from the circulation component main body in the other side of the seat direction and abutting against the second seat 12. The rib 60 and the crimping portion 70 are provided on each of the first arm 51 and the second arm 52.

[0134] According to the first embodiment, the deflector body 31 does not fall off into the through-hole 17. This stabilizes the posture of the middle deflector 30, allowing for smooth scooping of the ball 103. In addition, the number of crimped portions (crimped portions 70) provides a strong prevention of the middle deflector 30 from coming off.

[0135] The circulation component (middle deflector 30) of the first embodiment is formed by joining an inner component 81 and an outer component 82, which are separated by a separation surface 80 extending along the ball passage 34 when viewed in the axial direction. The inner component 81 has a first arm portion 51. The outer component 82 has a second arm portion 52.

[0136] The inner peripheral side part 81 and the outer peripheral side part 82 each have one arm part 50. Therefore, even if the connection between the inner peripheral side part 81 and the outer peripheral side part 82 is released, the inner peripheral side part 81 and the outer peripheral side part 82 will not fall into the through hole 17 or come off the nut body 1.

[0137] In addition, in the first embodiment, the pair of side surfaces 20 have a first side surface 20a located on one side of the circulation component (middle deflector 30) in the axial direction, and a second side surface 20b located on the other side of the circulation component in the axial direction. The rib 60 has a first rib 61 extending along the first side surface 20a and a second rib 62 extending along the second side surface 20b. The crimped portion 70 has a first crimped portion 71 that is part of the first rib 61 and is crimped toward the first side surface 20a, and a second crimped portion 72 that is part of the second rib 62 and is crimped toward the second side surface 20b.

[0138] According to the first embodiment, there are many crimped portions (crimped portions 70), and the middle deflector 30 is more securely prevented from coming off.

[0139] The ball screw device 100 of the first embodiment has been described above. Next, other embodiments in which the nut of the first embodiment is partially modified will be described. In the nut 101 of the first embodiment, a small gap (not shown) is generated between the first side surface 20a and the first opposing surface 36, or between the second side surface 20b and the second opposing surface 46, or between both, from the standpoint of tolerance. If the gap between the first side surface 20a and the first opposing surface 36 were large, the second opening 37 of the ball passage 34 would be separated from the opening 8a of the return path 8, preventing smooth transfer of the ball 103. Below, second to fourth embodiments in which this point has been improved will be described. Note that the following description will focus on changes from the first embodiment.

[0140] (Embodiment 2) Fig. 18 is a side view of the nut of embodiment 2 before the rib is crimped, viewed from the second bearing surface direction. Fig. 19 is a side view of the nut of embodiment 2 after the rib is crimped, viewed from the second bearing surface direction. As shown in Fig. 18, the middle deflector 30A of embodiment 2 differs from the middle deflector 30 of embodiment 1 in that it includes a first rib 61A and a second rib 62A that have different axial thicknesses. Note that while Fig. 18 shows only the ribs of the second arm portion, the first arm portion 51 also has a first rib 61A and a second rib 62A.

[0141] An axial thickness L12 of the second rib 62A is smaller than an axial thickness L11 of the first rib 61A. When the first rib 61A is crimped with a jig 120 (see FIG. 17B, etc.), a first crimped portion 71A is generated as shown in FIG. 19. When the second rib 62A is crimped with a jig 120 (see FIG. 17B, etc.), a second crimped portion 72A is generated.

[0142] When the first rib 61A and the second rib 62A are simultaneously crimped with the jig 120, the second rib 62A, which has a smaller axial thickness and less rigidity, begins to collapse (deform) earlier than the first rib 61A. The crimped portion of the second rib 62A (the second crimped portion 72A) contacts and presses against the inner surface of the recess 22 earlier than the crimped portion of the first rib 61A (the first crimped portion 71A). Therefore, a reaction force (see arrow A5) acts on the middle deflector 30A against the pressure of the second crimped portion 72A. The middle deflector 30A then moves in the first axial direction X1, and the first opposing surface 36 comes into contact with the first side surface 20a.

[0143] As described above, according to the second embodiment, the second opening 37 of the ball passage 34 and the opening 8a of the return passage 8 are continuous (adjacent), and the delivery of the ball 103 becomes smooth.

[0144] (Embodiment 3) Fig. 20 is a side view of the nut of embodiment 3 before the rib is crimped, viewed from the second seating surface direction. Fig. 21 is a side view of the nut of embodiment 3 after the rib is crimped, viewed from the second seating surface direction. As shown in Fig. 20, the middle deflector 30B of embodiment 3 differs from the middle deflector 30 of embodiment 1 in that it includes a first rib 61B and a second rib 62B instead of the first rib 61 and the second rib 62.

[0145] The first rib 61B has a first crimping surface 61a facing the second axial direction X2. The second rib 62B has a second crimping surface 62a facing the first axial direction X1. The first crimping surface 61a and the second crimping surface 62a face each other. The first crimping surface 61a is an inclined surface that is inclined toward the first side surface 20a (toward the first axial direction X1) as it extends in the first perpendicular direction Z1.

[0146] When the first crimping surface 61a is crimped with the jig 120, part of the crimping load (load in the first axial direction X1) acting on the first crimping surface 61a is converted into a load in the second vertical direction Z2. That is, the load in the first axial direction X1 acting on the first rib 61B is reduced. Furthermore, the base side of the first rib 61B (the portion closer to the arm portion 50) has a large axial thickness and high rigidity. For these reasons, the first rib 61B is less likely to deform than the second rib 62B. Therefore, when the first rib 61B and the second rib 62B are crimped simultaneously with the jig 120, the first rib 61B collapses slower than the second rib 62B. Therefore, the crimped portion of the second rib 62B (second crimping portion 72B) abuts against the inner surface of the recess 22 before the first rib 61B and further presses the inner surface of the recess 22. As a result, the second crimping portion 72B receives a reaction force (see arrow A7) from the inner surface of the recess 22, the middle deflector 30B moves in the first axial direction X1, and the first opposing surface 36 comes into contact with the first side surface 20a.

[0147] As described above, according to the third embodiment, the second opening 37 of the ball passage 34 and the opening 8a of the return passage 8 are continuous (adjacent), and the delivery of the ball 103 becomes smooth.

[0148] (Embodiment 4) Fig. 22 is a perspective view of the middle deflector of embodiment 4 as viewed from the second axial direction. Fig. 23 is an enlarged view of the gap between the second side surface and the second opposing surface of the nut of embodiment 4 as viewed from the first vertical direction. As shown in Fig. 22, the middle deflector 30C of embodiment 4 differs from the middle deflector 30 of embodiment 1 in that a plurality of protrusions 47 are provided on the second opposing surface 46.

[0149] The protrusion 47 is a protrusion formed integrally with the middle deflector 30C. The protrusion 47 is hemispherical. Therefore, a cross section of the protrusion 47 cut along a plane extending in the seating direction and perpendicular to the seating direction is circular. The amount of protrusion of the protrusion 47 in the axial direction is greater than the minute axial gap (tolerance) that occurs between the first housing portion 5 and the middle deflector 30C.

[0150] As shown in FIG. 23, when the middle deflector 30C of the fourth embodiment is inserted into the first housing portion 5, the protrusion 47 is pressed against the second side surface 20b, and the tip of the protrusion 47 is crushed. As a result, the middle deflector 30C is pressed in the first axial direction X1 (see arrow A8 in FIG. 23), and the first opposing surface 36 abuts against the first side surface 20a. As described above, according to the fourth embodiment, the second opening 37 of the ball passage 34 and the opening 8a of the return path 8 are continuous (adjacent), thereby enabling smooth transfer of the ball 103. Note that while the present embodiment has a plurality of protrusions 47, the present disclosure is only required to have at least one protrusion 47. Furthermore, the shape of the protrusion 47 is not limited to a hemisphere and may be a cylinder, a prism, a pyramid, or a frustum, and is not particularly limited.

[0151] Although the second to fourth embodiments have been described above, the present disclosure may combine the technical contents of the second to fourth embodiments. That is, the present disclosure may apply all of the second to fourth embodiments. Alternatively, the present disclosure may apply two of the second to fourth embodiments selectively.

[0152] (Embodiment 5) Fig. 24A is a perspective view of the middle deflector of the fifth embodiment. Fig. 24B is a perspective view of the outer peripheral part of the fifth embodiment. The middle deflector 30D of the fifth embodiment differs from the middle deflector 30 of the first embodiment in that the length of the arm portion 50D in the seating direction is longer than the length of the rib 60 in the seating direction. That is, the tip end 50a of the arm portion 50D of the fifth embodiment protrudes outward in the seating direction beyond the tip end 60b of the rib 60. This middle deflector 30D increases the contact area with the seating surface 10, making the posture of the middle deflector 30D more stable.

[0153] The middle deflector 30D of the fifth embodiment differs from the middle deflector 30 of the first embodiment in that the positioning protrusions 38 are provided on both the first opposing surface 36 and the second opposing surface 46 (not shown in FIG. 24A, see FIGS. 11 and 12). Although not specifically shown, the nut body 1 also has positioning holes 26 on each of the first side surface 20a and the second side surface 20b. This allows the middle deflector 30D to more firmly position the nut body 1 in the seating direction. Furthermore, the present disclosure does not necessarily have to have the extended seating surface 43 (see FIG. 9) as in the middle deflector 30D of the fifth embodiment.

[0154] Furthermore, according to the fifth embodiment, the positioning protrusions 38 are provided on both the first opposing surface 36 and the second opposing surface 46, and there is a possibility that the middle deflector 30 may be placed in the first storage section 5 in an incorrect orientation. Therefore, in the middle deflector 30D of the fifth embodiment, it is preferable to provide a mark on the outer peripheral surface of the deflector body (circulation component body) 31 indicating the assembly direction of the deflector body (circulation component body) 31 relative to the first storage section (storage section) 5.

[0155] 24B , the protrusion 89D of the fifth embodiment differs from the middle deflector 30 of the first embodiment in that it extends from the first opening 33a to the second opening 37. That is, the outer circumferential rolling surface 86 of the fifth embodiment is a groove surface 89a extending from the first opening 33a to the second opening 37. An edge 89b of the groove surface 89a on one side of the longitudinal direction of the ball passage 34 is disposed in the first opening 33a. An edge 89d of the groove surface 89a on the other side of the longitudinal direction of the ball passage 34 is disposed in the second opening 37.

[0156] According to this, although the balls 103 are more likely to become clogged than in the first embodiment, the balls 103 are transferred more smoothly between the ball passage 34 and the return path 8. Also, the area of ​​the groove surface 89a of the outer-circumferential rolling surface 86 is increased. That is, the number of areas where the surface pressure is small increases, and wear and damage to the outer-circumferential rolling surface 86 (groove surface 89a) can be suppressed. Also, the area of ​​contact between the side surface 89c of the protrusion 89D and the pair of side surfaces 85b increases. Therefore, it is possible to prevent the inner-circumferential side component 81 and the outer-circumferential side component 82 from being joined in a misaligned state.

[0157] (Embodiment 6) Fig. 25 is a side view of the middle deflector of embodiment 6 as seen from the first axial direction. Fig. 26 is a cross-sectional view of the middle deflector of embodiment 6 cut along a plane extending in the seating direction and vertical direction. As shown in Fig. 25, the middle deflector 30E of embodiment 6 differs from the middle deflector 30 of embodiment 1 in that it has an inner peripheral side part 81E and an outer peripheral side part 82E instead of the inner peripheral side part 81 and the outer peripheral side part 82.

[0158] When viewed from the axial direction, the dividing surface 90 between the inner peripheral side component 81E and the outer peripheral side component 82E includes an inclined surface 91 extending along the ball passage 34, a horizontal surface 92 extending in the first seating surface direction Y1 from the radially outer end of each end of the inclined surface 91, and a vertical surface 93 extending in the second vertical direction Z2 from the first seating surface direction Y1 of the horizontal surface 92. In addition, a fitting portion 94 is provided on the vertical surface 93.

[0159] Hereinafter, of the inner divided surface 83E of the inner part 81E, the portion located on the slope 91 will be referred to as the inner divided surface 91a, the portion located on the horizontal surface 92 will be referred to as the inner divided surface 93a, and the portion located on the vertical surface 93 will be referred to as the inner divided surface 91b, the portion located on the horizontal surface 92 will be referred to as the outer divided surface 93b, and the portion located on the vertical surface 93 will be referred to as the outer divided surface 93b.

[0160] The inclined surface 91 is inclined toward the first seating surface direction Y1 as it extends in the first vertical direction Z1. The inclined surface 91 overlaps the center of the ball passage 34 when viewed axially. Therefore, as shown in FIG. 26 , the inner inclined surface 91a and the inner lateral surface 92a of the inner part 81E are provided with a C-shaped (groove) inner rolling surface 85a that opens in the first vertical direction Z1. The outer inclined surface 91b and the outer lateral surface 92b of the outer part 82E are provided with an outer rolling surface 86 that opens in the second vertical direction Z2. The entire outer rolling surface 86 is a grooved surface 89a from the first opening 33a to the second opening 37. Therefore, the inner divided surface 83E and the outer divided surface 84E are provided with grooved surfaces (the inner rolling surface 85a and the grooved surface 89a). Therefore, the balls 103 roll in the ball passages 34 more smoothly than in the first embodiment.

[0161] The horizontal surface 92 is parallel to the seating surface 10. The vertical surface 93 is parallel to the vertical direction. The fitting portion 94 has a protrusion 95 and a groove 96. The protrusion 95 protrudes from the inner vertical surface 93a in the first seating surface direction Y1. The groove 96 is recessed from the outer vertical surface 93b in the first seating surface direction Y1. The protrusion 95 and the groove 96 each extend in the axial direction. The protrusion 95 is inserted into the groove 96 in the axial direction and fits into it.

[0162] The inner peripheral part 81E of the sixth embodiment has a tongue 35 and an inner peripheral rolling surface 85a. The outer peripheral part 82E has an outer peripheral rolling surface 86 and two arm portions 50.

[0163] As described above, the middle deflector 30E of the sixth embodiment is formed by joining an inner part 81E and an outer part 82E, which are divided by a dividing surface 90 extending along the ball passage 34 when viewed in the axial direction. The inner part 81E has a tongue 35 that scoops up the balls 103 from the raceway 106, an inner rolling surface 85a that surrounds the inner side of the ball passage 34, and an inner divided surface 83E that extends along the dividing surface. The outer part 82E has an outer rolling surface 86 that surrounds the outer side of the ball passage 34, two arms 50, and an outer divided surface 84E that extends along the dividing surface 90. One of the inner divided surface 83E and the outer divided surface 84E of the outer part 82E is provided with a protrusion 95 that protrudes toward the seating surface and extends in the axial direction. The other of the inner divided surface 83E and the outer divided surface 84E of the outer part 82E is provided with a groove 96 that is recessed toward the seating surface and extends in the axial direction, into which the protrusion 95 fits.

[0164] According to the middle deflector 30E of the sixth embodiment, similar to the first embodiment, the middle deflector 30E has a crimped portion (not shown in FIGS. 25 and 26 ) and is therefore not displaced in the first vertical direction Z1. Furthermore, even if the inner peripheral part 81E and the outer peripheral part 82E are disengaged from each other, the outer peripheral part 82E has two arms 50 and is therefore not displaced in the vertical direction. On the other hand, although the inner peripheral part 81E does not have arms 50, the protrusions 95 are caught in the grooves 96, and are not displaced in the second vertical direction Z2. In other words, the inner peripheral part 81E is prevented from falling into the through hole 17. Furthermore, the tongue 35 is integrally formed on the inner peripheral part 81E without being separated. Therefore, the strength of the tongue 35 is maintained, and the ball 103 is smoothly scooped up.

[0165] Furthermore, when the bond between the inner peripheral part 81E and the outer peripheral part 82E is released and the inner peripheral part 81E slides in the axial direction, it comes into contact with the edge 17a of the through hole 17 (see FIG. 4). This prevents the protrusion 95 from sliding in the axial direction and disengaging from the groove 96. Furthermore, the outer peripheral inclined surface 91b is disposed in the second seating surface direction Y2 of the groove 96. This prevents the inner peripheral part 81E from moving in the second seating surface direction Y2 and disengaging from the groove 96. As a result, the inner peripheral part 81E is restricted from moving in the direction that would release the engagement. Therefore, the inner peripheral part 81E does not separate from the outer peripheral part 82E and does not fall out of the through hole 17. In the outer peripheral part 82E of embodiment 6, the entire outer peripheral rolling surface 86 is a groove surface 89a, but in the present disclosure, as in embodiment 1, the groove surface 89a may be provided only in the portion close to the first opening 33a, and the remaining portion of the outer peripheral rolling surface 86 may be flat.

[0166] (Embodiment 7) FIG. 27 is a side view of the middle deflector of the seventh embodiment as viewed from the first axial direction. The middle deflector 30F of the seventh embodiment differs from the middle deflectors 30 of the other embodiments in that it does not have a dividing surface 80. That is, the middle deflector 30F is formed as a single unit. Such a middle deflector 30F can be manufactured using a 3D printer. As with the other embodiments, the middle deflector 30F also has a crimped portion (not shown in FIG. 27) that restricts misalignment in the first vertical direction Z1. Note that, in this embodiment as well, a groove surface 89a is provided on the outer periphery of the first opening.

[0167] (Embodiment 8) Fig. 28 is a perspective view of an inner peripheral side part of the middle deflector of embodiment 8. Fig. 29 is a perspective view of an outer peripheral side part of the middle deflector of embodiment 8. As shown in Fig. 28, the middle deflector 30G of embodiment 8 differs from the middle deflector 30 of embodiment 1 in that a groove surface 89a is provided in an inner peripheral side part 81G.

[0168] As shown in FIG. 28, the inner peripheral part 81G has a pair of side surfaces 85b. The pair of side surfaces 85b are provided with a pair of protrusions 89G that protrude toward the ball passage 34. The pair of protrusions 89G are arranged closer to the first opening 33a in the longitudinal direction of the pair of side surfaces 85b. The protrusions 89G have an arc surface 89e that forms an arc shape when viewed from the direction of the imaginary line K2 (see FIGS. 7 and 13). Furthermore, the cross-sectional shape of the arc surface 89e (the cross-sectional shape cut in a direction perpendicular to the imaginary line K2) becomes larger as it approaches the first opening 33a. Therefore, the pair of surfaces 89e cooperate with each other to form the groove surface 89a.

[0169] 29, the outer peripheral divided surface 84 of the outer peripheral part 82G is flat. A part of the outer peripheral divided surface 84G forms a flat surface 86a that covers the outer peripheral side of the ball passage 34. Therefore, the outer peripheral rolling surface 86 of this embodiment is composed of the groove surface 89a and the flat surface 86a.

[0170] As described above, according to the middle deflector 30G of the eighth embodiment, the shape of the outer peripheral side part 82G is simplified, making it easier to manufacture the outer peripheral side part 82G. Furthermore, although a load from the ball 103 acts on the groove surface 89a, the groove surface 89a is provided on the inner peripheral side part 81G. Therefore, the load acting on the outer peripheral side part 82G in the outer circumferential direction is reduced compared to other embodiments. Therefore, separation between the inner peripheral side part 81G and the outer peripheral side part 83G is suppressed. Note that, in this embodiment, the pair of protrusions 89G is provided only on the first opening of the pair of side surfaces 85b. However, in the present disclosure, the pair of protrusions 89G (groove surfaces 89a) may be provided on the pair of side surfaces 85b from the first opening 33a to the second opening 37.

[0171] Although each embodiment has been described above, the present disclosure is not limited to the middle deflector 30 and the first housing portion 5 (seat surface 10) extending in a direction perpendicular to the axis O (see FIG. 4 ) when viewed from the outer periphery. For example, the middle deflector 30 and the first housing portion 5 (seat surface 10) may extend in a direction parallel to the track 106. In other words, when viewed from the outer periphery, they may be inclined in a direction other than perpendicular to the axis O, and are not particularly limited. Furthermore, when the middle deflector 30 and the seat surface 10 are arranged at an angle, the through hole 17 may be inclined in the same direction as the seat surface 10.

[0172] Furthermore, in the embodiment, the crimping portions 70 (first crimping portion 71, second crimping portion 72) are provided on both axial sides of the arm portion 50, but in the present disclosure, the crimping portions 70 may be provided on only one axial side of the arm portion 50. Furthermore, in the embodiment, the crimping portions 70 are provided on both the first arm portion 51 and the second arm portion 52, but the crimping portions 70 may be provided on only one of the first arm portion 51 and the second arm portion 52.

[0173] Although the outer peripheral surface 32a of the middle deflector 30 in the embodiment is arc-shaped, the outer peripheral surface 32a of the middle deflector 30 in the present disclosure does not have to be arc-shaped. Also, in the present disclosure, the distance from the axis O to the outer peripheral surface 32a of the middle deflector 30 may be smaller than the outer diameter of the nut body 1.

[0174] Furthermore, although the expandable seat surface 13 in the embodiment has a first expandable seat surface 14 and a second expandable seat surface 15, the present disclosure may also be an expandable seat surface 13 consisting of either the first expandable seat surface 14 or the second expandable seat surface 15.

[0175] The present disclosure may also be implemented as a combination of the following configurations. (1) The nut body has a cylindrical shape and is inserted into a screw shaft, and a circulating part assembled to the nut body. The nut body has an inner circumferential raceway surface provided on its inner circumferential surface and facing an outer circumferential raceway surface of the screw shaft, an accommodating section formed by recessing a portion of the outer circumferential surface of the nut body, a seat surface forming a bottom surface of the accommodating section, and a through hole that penetrates the seat surface and the inner circumferential surface of the nut body and cuts out a portion of the inner circumferential raceway surface. The circulating part has a circulating part body that is placed in the accommodating section and the through hole, and an arm portion that extends from the circulating part body and abuts against the seat surface. The ring component body is provided with a first opening that opens toward the raceway between the outer peripheral raceway surface and the inner peripheral raceway surface, and a ball passage that extends from the first opening along a tangent to an imaginary circle formed by connecting the centers of a plurality of balls that roll on the raceway, and the inner surface of the ball passage has an inner peripheral rolling surface that is located on the inner side of the tangent, and an outer peripheral rolling surface that is located on the outer side of the tangent, and at least a portion of the outer peripheral rolling surface that is closer to the first opening is a groove surface, and the groove surface is continuous with the edge portion of the inner peripheral raceway surface that is cut out by the through hole. (2) The nut according to (1), wherein the ball passage has a curved portion that changes the direction of movement of the ball, and the outer circumferential rolling surface is flat at the curved portion. (3) The nut described in (1) has a second opening, which is an opening of the ball passage and is provided on the opposite side of the first opening, and the outer rolling surface is a groove surface from the first opening to the second opening. (4) The nut according to any one of (1) to (3), wherein the groove shape of the edge of the groove surface is larger than the groove shape of the edge of the inner circumferential raceway surface. (5) The nut described in any one of (1) to (4) has a second opening, which is an opening of the ball passage and is provided on the opposite side of the first opening, and the second opening is chamfered. (6) The nut according to any one of (1) to (5), wherein the circulating part is formed by joining an inner part and an outer part which are divided by a dividing surface extending along the ball passage when viewed from an axial direction parallel to the screw axis, and the groove surface is provided on the outer part. (7) The nut according to any one of (1) to (5), wherein the circulating part is formed by joining an inner part and an outer part which are divided by a dividing surface extending along the ball passage when viewed from an axial direction parallel to the screw axis, and the groove surface is provided on the inner part. (8) The nut body is arranged on both sides of the accommodating portion in the axial direction parallel to the screw axis and has a pair of side surfaces facing each other, the accommodating portion is arch-shaped when viewed from the axial direction, the direction parallel to the seating surface when viewed from the axial direction is the seating surface direction, the direction perpendicular to the seating surface and the direction in which the seating surface faces is a first vertical direction, the circulating part has a rib protruding from the arm portion in the first vertical direction and extending along the side surface in the seating surface direction, and a crimped portion formed by crimping at least a part of the rib toward the side surface, and the pair of side surfaces are provided with grooves extending in the seating surface direction, facing the rib in the axial direction, and recesses into which the crimped portion fits. A nut described in any one of (1) to (7). (9) The through hole penetrates the center of the seat in the seat direction, and the seat has a first seat positioned on one side of the seat direction relative to the through hole, and a second seat positioned on the other side of the seat direction relative to the through hole, and the arm portion has a first arm portion extending from the circulating part main body in one side of the seat direction and abutting the first seat surface, and a second arm portion extending from the circulating part main body in the other side of the seat direction and abutting the second seat surface, and the rib and the crimping portion are provided on each of the first arm portion and the second arm portion. (10) The nut described in (9) above, wherein the circulating part is formed by joining an inner part and an outer part which are divided by a dividing surface extending along the ball passage when viewed from the axial direction, and the inner part has the first arm portion, and the outer part has the second arm portion. (11) The nut described in (9) above, wherein the circulating part is formed by joining an inner part and an outer part which are divided by a dividing surface extending along the ball passage when viewed from the axial direction, the outer part having an outer divided surface extending along the dividing surface, the first arm portion and the second arm portion, the inner part having an inner divided surface extending along the dividing surface, one of the inner divided surface and the outer divided surface having a protrusion which protrudes toward the seat surface and extends in the axial direction, and the other of the inner divided surface and the outer divided surface having a groove which is recessed toward the seat surface and extends in the axial direction and into which the protrusion fits. (12) The dividing surface is parallel to the tangent when viewed from the axial direction, and has an inclined surface that is positioned on one side of the seating surface direction as it approaches the first vertical direction, and a vertical surface that is positioned on one side of the seating surface direction relative to the inclined surface and extends in the first vertical direction, the protrusion and the groove are provided on the vertical surface, and the movement of the inner peripheral side part in a direction that releases the engagement between the protrusion and the groove is restricted by the inclined surface. (13) A nut described in any one of (8) to (12), wherein the pair of side surfaces have a first side surface positioned on one side of the axial direction relative to the circulating part and a second side surface positioned on the other side of the axial direction relative to the circulating part, the rib has a first rib extending along the first side surface and a second rib extending along the second side surface, and the crimping portion has a first crimping portion that is part of the first rib and crimped toward the first side surface, and a second crimping portion that is part of the second rib and crimped toward the second side surface. (14) A ball screw device comprising a nut according to any one of (1) to (13), a screw shaft passing through the nut, and a plurality of balls arranged between the nut and the screw shaft. [Explanation of symbols]

[0176] 1 Nut body 5 First storage section (storage section) 8 Return 10 Seat 11 First seat 12 Second seat 13 Extended seat 14 First Extended Seat 15 Second extended seat 17 Through hole 18 Inner surface 18b Notch 18c edge 20 Side 20a First side 20b 2nd side 22 recess 22a First recess 22b Second recess 23, 23a, 23b 1st slope 24, 24a, 24b 2nd slope 26 Positioning holes 30, 30A, 30B, 30C, 30D, 30E, 30F, 30G Middle deflector (circulation device) 31 Deflector body (circulation part body) 32 Main body 33 Scooping section 33a 1st opening 34 Ball Passage 36 First opposing surface 37 Second Opening 38 Positioning protrusion 40 seating surface 41 First seating surface 42 Second seating surface 43 Extended seating surface 44 First extended seating surface 45 Second extended seating surface 46 Second opposing surface 47 Convex part 50, 50D arm 51 1st arm 52 2nd arm 53 First seating surface for arm 54 Second seating surface for arm 60 Ribs 61, 61A, 61B First rib 61a First crimping surface 62, 62A, 62B Second rib 62a Second crimping surface 70 Crimping part 71, 71A, 71B First crimping part 72, 72A, 72B Second crimping part 80, 90 split plane 81, 81E, 81G Inner parts 82, 82E, 82G Outer periphery parts 83, 83E Inner circumferential side dividing surface 84, 84E Outer peripheral division surface 85 Groove surface for passage 85a Inner rolling surface 86 Outer circumferential rolling surface 86a plane 87 Step surface 88 End face 89 Protrusion 89a Groove surface 89b Edge 91 Slope 91a Inner slope 91b Outer slope 92 Side 92a Inner side 92b Outer periphery side 93 Vertical 93a Inner vertical surface 93b Outer circumferential vertical surface 94 Fitting part 95 protrusion 96 Groove 100 Ball screw device 101 Nut 102 screw shaft 103 Ball 120 Jig

Claims

1. a cylindrical nut body that is passed through by the screw shaft; a circulation part assembled to the nut body; Equipped with The nut body is an inner peripheral raceway surface provided on the inner peripheral surface and facing an outer peripheral raceway surface of the screw shaft; An accommodating portion formed by recessing a part of the outer peripheral surface of the nut body; a seat surface forming a bottom surface of the storage portion; a through hole that penetrates the seat surface and the inner peripheral surface of the nut body and cuts out a part of the inner peripheral raceway surface; and The circulating part is a circulation component body disposed in the accommodation portion and the through hole; an arm portion extending from the circulation component body and abutting against the seating surface; and The circulating part body is a first opening that opens toward a raceway between the outer circumferential raceway surface and the inner circumferential raceway surface; a ball passage extending from the first opening along a tangent to an imaginary circle connecting the centers of the balls rolling on the raceway; Equipped with The inner surface of the ball passage is an inner rolling surface disposed on the inner circumferential side of the tangent line; an outer circumferential rolling surface disposed on the outer circumferential side of the tangent line; and At least a portion of the outer circumferential rolling surface close to the first opening is a groove surface, the groove surface is continuous with an edge portion of the inner circumferential raceway surface that is cut out by the through hole, the ball passage has a curved portion that changes the direction of movement of the ball; The outer circumferential rolling surface is flat at the bent portion. nut.

2. a cylindrical nut body that is passed through by the screw shaft; a circulation part assembled to the nut body; Equipped with The nut body is an inner peripheral raceway surface provided on the inner peripheral surface and facing an outer peripheral raceway surface of the screw shaft; An accommodating portion formed by recessing a part of the outer peripheral surface of the nut body; a seat surface forming a bottom surface of the storage portion; a through hole that penetrates the seat surface and the inner peripheral surface of the nut body and cuts out a part of the inner peripheral raceway surface; and The circulating part is a circulation component body disposed in the accommodation portion and the through hole; an arm portion extending from the circulation component body and abutting against the seating surface; and The circulating part body is a first opening that opens toward a raceway between the outer circumferential raceway surface and the inner circumferential raceway surface; a ball passage extending from the first opening along a tangent to an imaginary circle connecting the centers of the balls rolling on the raceway; Equipped with The inner surface of the ball passage is an inner rolling surface disposed on the inner circumferential side of the tangent line; an outer circumferential rolling surface disposed on the outer circumferential side of the tangent line; and At least a portion of the outer circumferential rolling surface close to the first opening is a groove surface, the groove surface is continuous with an edge portion of the inner circumferential raceway surface that is cut out by the through hole, the circulating component is formed by joining an inner peripheral component and an outer peripheral component that are divided at a dividing surface that extends along the ball passage when viewed in an axial direction parallel to the screw shaft, The groove surface is provided on the outer peripheral side component. nut.

3. a cylindrical nut body that is passed through by the screw shaft; a circulation part assembled to the nut body; Equipped with The nut body is an inner peripheral raceway surface provided on the inner peripheral surface and facing an outer peripheral raceway surface of the screw shaft; An accommodating portion formed by recessing a part of the outer peripheral surface of the nut body; a seat surface forming a bottom surface of the storage portion; a through hole that penetrates the seat surface and the inner peripheral surface of the nut body and cuts out a part of the inner peripheral raceway surface; and The circulating part is a circulation component body disposed in the accommodation portion and the through hole; an arm portion extending from the circulation component body and abutting against the seating surface; and The circulating part body is a first opening that opens toward a raceway between the outer circumferential raceway surface and the inner circumferential raceway surface; a ball passage extending from the first opening along a tangent to an imaginary circle connecting the centers of the balls rolling on the raceway; Equipped with The inner surface of the ball passage is an inner rolling surface disposed on the inner circumferential side of the tangent line; an outer circumferential rolling surface disposed on the outer circumferential side of the tangent line; and At least a portion of the outer circumferential rolling surface close to the first opening is a groove surface, the groove surface is continuous with an edge portion of the inner circumferential raceway surface that is cut out by the through hole, the circulating component is formed by joining an inner peripheral component and an outer peripheral component that are divided at a dividing surface that extends along the ball passage when viewed in an axial direction parallel to the screw shaft, The groove surface is provided on the inner peripheral side part. nut.

4. a cylindrical nut body that is passed through by the screw shaft; a circulation part assembled to the nut body; Equipped with The nut body is an inner peripheral raceway surface provided on the inner peripheral surface and facing an outer peripheral raceway surface of the screw shaft; An accommodating portion formed by recessing a part of the outer peripheral surface of the nut body; a seat surface forming a bottom surface of the storage portion; a through hole that penetrates the seat surface and the inner peripheral surface of the nut body and cuts out a part of the inner peripheral raceway surface; and The circulating part is a circulation component body disposed in the accommodation portion and the through hole; an arm portion extending from the circulation component body and abutting against the seating surface; and The circulating part body is a first opening that opens toward a raceway between the outer circumferential raceway surface and the inner circumferential raceway surface; a ball passage extending from the first opening along a tangent to an imaginary circle connecting the centers of the balls rolling on the raceway; Equipped with The inner surface of the ball passage is an inner rolling surface disposed on the inner circumferential side of the tangent line; an outer circumferential rolling surface disposed on the outer circumferential side of the tangent line; and At least a portion of the outer circumferential rolling surface close to the first opening is a groove surface, the groove surface is continuous with an edge portion of the inner circumferential raceway surface that is cut out by the through hole, The nut body is arranged on both sides of the accommodating portion in an axial direction parallel to the screw shaft and has a pair of side surfaces facing each other, The housing portion has an arch shape when viewed from the axial direction, A direction parallel to the seat surface when viewed from the axial direction is a seat surface direction, a direction perpendicular to the seat surface and in which the seat surface faces is a first vertical direction; The circulating part is a rib protruding from the arm portion in the first vertical direction and extending along the side surface toward the seat surface; a crimped portion formed by crimping at least a portion of the rib toward the side surface; and The pair of side surfaces are provided with recesses, which are grooves extending in the seating surface direction, facing the ribs in the axial direction, and into which the crimping portion is inserted, The through hole penetrates a central portion of the seat surface in the seat surface direction, The seating surface is a first seating surface disposed on one side of the through hole in the seating surface direction; a second seating surface disposed on the other side of the through hole in the seating surface direction; and The arm portion is a first arm portion extending from the circulation component body in one direction toward the seating surface and abutting against the first seating surface; a second arm portion extending from the circulation component body in the other direction in the seating surface direction and abutting against the second seating surface; and the rib and the crimping portion are provided on the first arm portion and the second arm portion, respectively; the circulating component is formed by joining an inner peripheral component and an outer peripheral component that are divided at a dividing surface that extends along the ball passage when viewed from the axial direction, the inner peripheral side component has the first arm portion, The outer peripheral part has the second arm portion. nut.

5. a cylindrical nut body that is passed through by the screw shaft; a circulation part assembled to the nut body; Equipped with The nut body is an inner peripheral raceway surface provided on the inner peripheral surface and facing an outer peripheral raceway surface of the screw shaft; An accommodating portion formed by recessing a part of the outer peripheral surface of the nut body; a seat surface forming a bottom surface of the storage portion; a through hole that penetrates the seat surface and the inner peripheral surface of the nut body and cuts out a part of the inner peripheral raceway surface; and The circulating part is a circulation component body disposed in the accommodation portion and the through hole; an arm portion extending from the circulation component body and abutting against the seating surface; and The circulating part body is a first opening that opens toward a raceway between the outer circumferential raceway surface and the inner circumferential raceway surface; a ball passage extending from the first opening along a tangent to an imaginary circle connecting the centers of the balls rolling on the raceway; Equipped with The inner surface of the ball passage is an inner rolling surface disposed on the inner circumferential side of the tangent line; an outer circumferential rolling surface disposed on the outer circumferential side of the tangent line; and At least a portion of the outer circumferential rolling surface close to the first opening is a groove surface, the groove surface is continuous with an edge portion of the inner circumferential raceway surface that is cut out by the through hole, The nut body is arranged on both sides of the accommodating portion in an axial direction parallel to the screw shaft and has a pair of side surfaces facing each other, The housing portion has an arch shape when viewed from the axial direction, A direction parallel to the seat surface when viewed from the axial direction is a seat surface direction, a direction perpendicular to the seat surface and in which the seat surface faces is a first vertical direction; The circulating part is a rib protruding from the arm portion in the first vertical direction and extending along the side surface toward the seat surface; a crimped portion formed by crimping at least a portion of the rib toward the side surface; and The pair of side surfaces are provided with recesses, which are grooves extending in the seating surface direction, facing the ribs in the axial direction, and into which the crimping portion is inserted, The through hole penetrates a central portion of the seat surface in the seat surface direction, The seating surface is a first seating surface disposed on one side of the through hole in the seating surface direction; a second seating surface disposed on the other side of the through hole in the seating surface direction; and The arm portion is a first arm portion extending from the circulation component body in one direction toward the seating surface and abutting against the first seating surface; a second arm portion extending from the circulation component body in the other direction in the seating surface direction and abutting against the second seating surface; and the rib and the crimping portion are provided on the first arm portion and the second arm portion, respectively; the circulating component is formed by joining an inner peripheral component and an outer peripheral component that are divided at a dividing surface that extends along the ball passage when viewed from the axial direction, The outer peripheral part is an outer peripheral dividing surface extending along the dividing surface; the first arm portion and the second arm portion; and the inner part has an inner dividing surface extending along the dividing surface, a protrusion protruding toward the bearing surface and extending in the axial direction is provided on one of the inner peripheral divided surface and the outer peripheral divided surface, The other of the inner peripheral divided surface and the outer peripheral divided surface is provided with a groove portion that is recessed toward the seat surface and extends in the axial direction, and into which the protrusion is fitted. nut.

6. The dividing surface is A slope that is parallel to the tangent line when viewed from the axial direction and is positioned toward one side of the seat surface direction as it extends toward the first vertical direction; a vertical surface disposed on one side of the inclined surface in the seating direction and extending in the first vertical direction; and The vertical surface is provided with the protrusion and the groove, The inclined surface restricts the movement of the inner peripheral part in a direction in which the engagement between the protrusion and the groove is released. The nut according to claim 5.

7. The pair of side surfaces are: a first side surface disposed on one side of the circulating component in the axial direction; a second side surface disposed on the other side of the circulation component in the axial direction; and The rib is a first rib extending along the first side; a second rib extending along the second side; and The crimped portion is a first crimped portion that is a part of the first rib and is crimped toward the first side surface; a second crimped portion that is a part of the second rib and is crimped toward the second side surface; have The nut according to claim 4.

8. The pair of side surfaces are: a first side surface disposed on one side of the circulating component in the axial direction; a second side surface disposed on the other side of the circulation component in the axial direction; and The rib is a first rib extending along the first side; a second rib extending along the second side; and The crimped portion is a first crimped portion that is a part of the first rib and is crimped toward the first side surface; a second crimped portion that is a part of the second rib and is crimped toward the second side surface; have The nut according to claim 5.

9. The circulation component body has a second opening which is an opening of the ball passage and is provided on the opposite side of the first opening, The outer circumferential rolling surface is a groove surface extending from the first opening to the second opening. The nut according to any one of claims 1 to 8.

10. The groove shape of the edge of the groove surface is larger than the groove shape of the edge of the inner circumferential raceway surface. The nut according to any one of claims 1 to 8.

11. The circulation component body has a second opening which is an opening of the ball passage and is provided on the opposite side of the first opening, The second opening is chamfered. The nut according to any one of claims 1 to 8.

12. A nut according to any one of claims 1 to 5, a screw shaft that passes through the nut; a plurality of balls disposed between the nut and the screw shaft; A ball screw device comprising:

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