Nut and ball screw device

Abstract

To provide a nut having high positioning accuracy of a circulation component.SOLUTION: The nut includes a nut main body and a circulation component. The nut main body has a housing portion, a bearing surface, a through hole, a pair of side surfaces, and a return passage. The circulation component has: a circulation component main body disposed on the housing portion and the through hole; and an arm portion extending in a bearing surface direction from the circulation component main body and kept into contact with the bearing surface. The pair of side surfaces have: a first side surface provided with an opening of the return passage; and a second side surface disposed on the other side in an axial direction with respect to the circulation component. The circulation component main body has: a ball passage in which balls roll; a first opposite surface opposed to the first side surface; and a second opposite surface opposed to the second side surface. At least one of the first side surface and the second side surface is axially recessed and provided with a positioning hole opened on an outer peripheral surface of the nut main body. One or both opposed to the side surface provided with the positioning hole, of the first opposite surface and the second opposite surface is provided with a positioning projection to be inserted to the positioning hole.SELECTED DRAWING: Figure 11A

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] According to the invention of the above-mentioned patent document, the circulating part is positioned (fixed) to the nut via a pin. In other words, the positioning of the circulating part depends on the accuracy of the pin and the accuracy of the through hole. For this reason, the positioning accuracy of the circulating part relative to the nut is low. If the circulating part is misaligned, the entrance and exit of the ball passage of the nut will be misaligned with the entrance and exit of the return passage of the nut, preventing smooth transfer of the balls. In addition, the balls will not be scooped up smoothly by the tongue. For these reasons, there is a need for the development of a nut that allows for high positioning accuracy of the circulating part.

[0006] The present disclosure has been made in consideration of the above, and aims to provide a nut and a ball screw device that have high positioning accuracy for circulating parts. [Means for solving the problem]

[0007] To achieve the above object, a nut according to a first aspect of the present disclosure includes a cylindrical nut body that is inserted through a screw shaft and a circulatory component assembled to the nut body. The nut body includes a recess on the outer peripheral surface of the nut body, a bow-shaped receiving portion when viewed from an axial direction parallel to the screw shaft, a seat forming the bottom of the receiving portion, a through-hole penetrating the seat and the inner peripheral surface of the nut body, a pair of opposing side surfaces disposed on both sides of the receiving portion in the axial direction, and a return path extending in the axial direction. The direction parallel to the seating surface when viewed from the axial direction is the seating surface direction. The circulatory component includes a circulatory component body disposed in the receiving portion and the through-hole, and an arm extending from the circulatory component body in the seating surface direction and abutting against the seating surface. The pair of side surfaces includes a first side surface disposed on one side of the circulatory component in the axial direction and provided with an opening for the return path, and a second side surface disposed on the other side of the circulatory component in the axial direction. The circulatory component body has a ball passage in which balls roll, a first opposing surface in which an opening of the ball passage is provided and which faces the first side surface, and a second opposing surface which faces the second side surface. At least one of the first side surface and the second side surface is provided with a positioning hole that is recessed in the axial direction and opens into the outer peripheral surface of the nut body. One or both of the first opposing surface and the second opposing surface that faces the side surface in which the positioning hole is provided is provided with a positioning protrusion that is inserted into the positioning hole.

[0008] According to the above-described invention, the arm portion of the circulative component abuts against the seating surface. Therefore, the circulative component is positioned at a predetermined assembly position in the vertical direction of the seating surface. Furthermore, the positioning protrusion abuts against the inner surface of the positioning hole. Therefore, the circulative component is positioned at a predetermined assembly position in the seating surface direction. Furthermore, since the circulative component is positioned directly relative to the nut without the need for other components, the positioning accuracy is high.

[0009] To achieve the above object, a nut according to a second aspect 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 includes a recess on the outer peripheral surface of the nut body, a bow-shaped receiving portion when viewed from an axial direction parallel to the screw shaft, a seat that forms the bottom of the receiving portion, a through-hole that penetrates the seat and the inner peripheral surface of the nut body, a pair of opposing side surfaces that are disposed on both sides of the receiving portion in the axial direction, and a return path that extends in the axial direction. The direction parallel to the seating surface when viewed from the axial direction is the seating surface direction. The circulatory component includes a circulatory component body that is disposed in the receiving portion and the through-hole, and an arm that extends from the circulatory component body in the seating surface direction and abuts against the seating surface. The pair of side surfaces includes a first side surface that is disposed on one side of the circulatory component in the axial direction and a second side surface that is disposed on the other side of the circulatory component in the axial direction. The circulatory component body has a ball passage in which balls roll, a first opposing surface opposing the first side surface, and a second opposing surface opposing the second side surface. The first side surface is provided with a positioning hole that is recessed in the axial direction and opens into the outer peripheral surface of the nut body. The first opposing surface is provided with a positioning protrusion that protrudes in the axial direction and is inserted into the positioning hole. An opening for the return path is provided on a first surface of the inner surface of the positioning hole that faces the other side in the axial direction. An opening for the ball passage is provided on a second surface of the side surface of the positioning protrusion that faces the first surface.

[0010] According to the above invention, the arm portion of the circulating part abuts against the seating surface. Therefore, the circulating part is positioned at a predetermined assembly position in the vertical direction of the seating surface. Furthermore, the positioning protrusion of the circulating part abuts against the inner surface of the positioning hole. Therefore, the circulating part is positioned at a predetermined assembly position in the direction of the seating surface. Since the circulating part is positioned directly relative to the nut without the intervention of other parts, the positioning accuracy is high. Furthermore, the opening of the return path and the opening of the ball passage are provided in the positioned positioning hole (first surface) and positioning protrusion (second surface). Therefore, the coaxiality of the opening of the return path and the opening of the ball passage is high, and balls can be transferred more smoothly.

[0011] In a preferred embodiment of the nut, at least one of the first side surface and the second side surface is provided with a positioning hole recessed in the axial direction and opening onto the outer peripheral surface of the nut body, and one or both of the first opposing surface and the second opposing surface facing the side surface with the positioning hole provided with a positioning protrusion to be inserted into the positioning hole.

[0012] According to this configuration, the positioning protrusion abuts against the inner surface of the positioning hole, and the circulating part is positioned at a predetermined assembly position in the seating direction, thereby further improving positioning accuracy.

[0013] In a preferred embodiment of the nut, 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 in the first vertical direction and extending along the side surface toward the seating 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 toward the seating surface, face the ribs in the axial direction, and fit the crimped portion.

[0014] According to this configuration, when a load acts on the circulative part in the first vertical direction, the crimped portion is caught in the recessed portion, and therefore the circulative part does not move in the first vertical direction. In other words, the circulative part does not come off the nut body.

[0015] 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.

[0016] 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, when 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.

[0017] In a preferred embodiment of the nut, the rib has a first rib extending along the first side surface and a second rib extending along the second side surface, and the crimped portion has 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.

[0018] According to the above configuration, the crimping portion has a first crimping portion that hooks into the recess on the first side surface and a second crimping portion that hooks into the recess on the second side surface, and since there are many crimping points, the circulating part can be firmly prevented from coming loose.

[0019] In a preferred embodiment of the nut, the thickness of the second rib in the axial direction is smaller than the thickness of the first rib in the axial direction.

[0020] When the first rib and the second rib are crimped simultaneously, the second rib, which has a smaller axial thickness, begins to collapse (deform) earlier than the first rib. The crimped portion of the second rib (the second crimped portion) then contacts the recess before the first rib does, further pressing the recess. As a result, the second rib receives a reaction force from the inner surface of the recess, causing the circulation component to move toward the first side surface. This causes the first opposing surface to contact the first side surface, connecting the ball passage and the return path. This allows the balls to move smoothly.

[0021] In a preferred embodiment of the nut, the first rib has a first crimping surface facing the other side of the axial direction and crimped to form the first crimped portion, the first crimping surface being inclined toward the first side surface as it extends in the first vertical direction.

[0022] When the inclined surface (first crimping surface) is crimped with a jig, part of the crimping load (load in the direction of the first side) is converted into a load perpendicular to the seat surface. In other words, the load acting on the first rib in the direction of the first side is reduced. Furthermore, the base side of the first rib (the portion closer to the arm) is thick, making it highly rigid and less likely to deform. Therefore, when the first rib and the second rib are crimped simultaneously, the first rib collapses (deforms) slower than the second rib. Therefore, the crimped portion of the second rib (second crimping portion) contacts the recess before the first rib and further presses the recess. As a result, the second rib receives a reaction force from the inner surface of the recess, causing the circulation component to move toward the first side. Therefore, the first opposing surface and the first side contact each other, connecting the ball passage and the return path. This allows for smooth ball movement.

[0023] In a preferred embodiment of the nut, the nut body has another end face facing the other side in the axial direction, and a through hole that penetrates the other end face and the second side face in the axial direction and is coaxial with the return path.

[0024] According to the above configuration, the cutting tool can be inserted into the through-hole and the tip of the cutting tool can be brought into contact with the first side surface, that is, the first side surface can be cut (the return path can be formed). This makes it easy to form the return path.

[0025] In a preferred embodiment of the nut, the second opposing surface is recessed toward one side in the axial direction and is provided with a hole adjacent to the through hole in the axial direction. A pin is inserted into the through hole. One end of the pin in the axial direction is inserted into the hole.

[0026] According to this configuration, when a load acts on the circulating part in the bearing surface direction and the vertical direction, the inner surface of the hole catches on the pin, and therefore the circulating part does not shift in position in the bearing surface direction and the vertical direction.

[0027] In a preferred embodiment of the nut, the pin is fitted into the through hole.

[0028] According to this configuration, the pin does not fall out of the through hole.

[0029] In a preferred embodiment of the nut, the second opposing surface is provided with at least one protrusion that protrudes toward the other side in the axial direction and abuts against the second side surface, and the protrusion is crushed between the circulation component body and the second side surface.

[0030] According to the above configuration, when the circulation part is placed in the storage part, the convex part is crushed between the circulation part and the second side surface, and the circulation part is placed closer to the first side surface. In other words, the circulation part is placed closer to the first side surface, and the first opposing surface and the first side surface abut. As a result, the ball passage and the return path are continuous, and the movement of the balls is smooth.

[0031] In a preferred embodiment of the nut, the seating surface is an edge of the through hole and has an extended seating surface disposed in the axial direction relative to the through hole. The circulation component body has an extended seating surface abutting against the extended seating surface.

[0032] According to this configuration, the number of portions that come into contact with the seating surface increases, and the posture of the circulation component becomes more stable, thereby allowing the balls to be scooped up more smoothly.

[0033] To achieve the above object, a ball screw device according to a first aspect of the present disclosure includes a nut, a screw shaft penetrating the nut, and a plurality of balls arranged between the nut and the screw shaft. The nut includes a cylindrical nut body penetrated by the screw shaft and a circulatory component assembled to the nut body. The nut body includes a recess provided on the outer peripheral surface of the nut body, a bow-shaped accommodation portion when viewed from an axial direction parallel to the screw shaft, a seat forming the bottom of the accommodation portion, a through-hole penetrating the seat and the inner peripheral surface of the nut body, a pair of side surfaces arranged on both sides of the accommodation portion in the axial direction and facing each other, and a return path extending in the axial direction. The direction parallel to the seat direction when viewed from the axial direction is the seat direction. The circulatory component includes a circulatory component body arranged in the accommodation portion and the through-hole, and an arm portion extending from the circulatory component body in the seat direction and abutting the seat. The pair of side surfaces include a first side surface located on one side of the circulating component in the axial direction and having an opening for the return path, and a second side surface located on the other side of the circulating component in the axial direction. The circulating component body has a ball passage in which balls roll, a first opposing surface having an opening for the ball passage and facing the first side surface, and a second opposing surface facing the second side surface. At least one of the first side surface and the second side surface is provided with a positioning hole that is recessed in the axial direction and opens into the outer peripheral surface of the nut body. One or both of the first opposing surface and the second opposing surface that faces the side surface having the positioning hole is provided with a positioning protrusion that is inserted into the positioning hole.

[0034] To achieve the above object, a ball screw device according to a second aspect of the present disclosure includes a nut, a screw shaft penetrating the nut, and a plurality of balls arranged between the nut and the screw shaft. The nut includes a cylindrical nut body penetrated by the screw shaft and a circulatory component assembled to the nut body. The nut body includes a recess provided on the outer peripheral surface of the nut body, a bow-shaped accommodation portion when viewed from an axial direction parallel to the screw shaft, a seat forming the bottom of the accommodation portion, a through-hole penetrating the seat and the inner peripheral surface of the nut body, a pair of side surfaces arranged on both sides of the accommodation portion in the axial direction and facing each other, and a return path extending in the axial direction. The direction parallel to the seat direction when viewed from the axial direction is the seat direction. The circulatory component includes a circulatory component body arranged in the accommodation portion and the through-hole, and an arm portion extending from the circulatory component body in the seat direction and abutting the seat. The pair of side surfaces have a first side surface located on one side of the circulatory component in the axial direction and a second side surface located on the other side of the axial direction relative to the circulatory component. The circulatory component body has a ball passage in which balls roll, a first opposing surface facing the first side surface, and a second opposing surface facing the second side surface. The first side surface is provided with a positioning hole that is recessed in the axial direction and opens into the outer peripheral surface of the nut body. The first opposing surface is provided with a positioning protrusion that protrudes in the axial direction and is inserted into the positioning hole. A first surface of the inner surface of the positioning hole facing the other side in the axial direction is provided with an opening for the return path. A second surface of the side surface of the positioning protrusion that faces the first surface is provided with an opening for the ball passage.

[0035] According to the ball screw devices of the first and second aspects, the circulating part is positioned without any other parts being involved, and therefore the positioning accuracy is high. [Effects of the Invention]

[0036] According to the nut and ball screw device of the present disclosure, the positioning accuracy of the circulating parts is high, which allows smooth delivery of balls. [Brief explanation of the drawings]

[0037] [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 3] 3 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 4] FIG. 4 is a side view seen from the direction of arrow IV in FIG. [Figure 5] 5 is a side view seen from the direction of arrow V in FIG. [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 11A] FIG. 11A is a cross-sectional view taken along line XIA-XIA in FIG. [Figure 11B] 11B is a cross-sectional view taken along line XIB-XIB 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 showing a preparation step of the assembling method of the first embodiment. [Figure 14] FIG. 14 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 15] FIG. 15 is a side view of the state after crimping, as viewed from the second seating surface direction, in the crimping step of the assembling method of the first embodiment. [Figure 16] FIG. 16 is a plan view showing the crimping step of the first embodiment as viewed from the first vertical direction. [Figure 17] FIG. 17 is a perspective view showing a state in which two jigs are used for crimping 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 24] FIG. 24 is a perspective view of the middle deflector 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 view of the middle deflector and its periphery according to the eighth embodiment, viewed from the outer periphery side. [Figure 29] FIG. 29 is a perspective view of the middle deflector of the eighth embodiment before crimping, as viewed from the first axial direction. [Figure 30]FIG. 30 is a view of the first side surface of the eighth embodiment as viewed from the second axis direction. [Figure 31] FIG. 31 is a cross-sectional view taken along line XXXI-XXXI in FIG. [Figure 32] FIG. 32 is a view of the middle deflector and its periphery according to the ninth embodiment, viewed from the outer periphery side. [Figure 33] FIG. 33 is a perspective view of the middle deflector of the ninth embodiment before crimping, as viewed from the first axial direction. [Figure 34] FIG. 34 is a perspective view of the nut body of the ninth embodiment as viewed from the second axial direction. [Figure 35] FIG. 35 is a cross-sectional view taken along line XXXI-XXXI in FIG. [Figure 36] FIG. 36 is a cross-sectional view taken along line XXXVI-XXXVI in FIG. [Figure 37] FIG. 37 is a cross-sectional view taken along line XXXVII-XXXVII in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0038] 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.

[0039] (Embodiment 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. 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.

[0040] 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.

[0041] 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.

[0042] Fig. 2 is an axial cross-sectional view 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] Fig. 3 is a cross-sectional view of the nut body taken along line III-III in Fig. 1, viewed from the direction of the arrow. As shown in Fig. 3, 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. 3) arranged on both axial sides of the first accommodating portion 5.

[0048] 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.

[0049] 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).

[0050] 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.

[0051] 4 is a side view seen from the direction of arrow IV in FIG. 3. 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. 3, 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. 3. 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] As shown in Fig. 3, the first side surface 20a is provided with an opening 8a which is an entrance and exit of 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. The ball passage 34 extends in the tangent direction (see imaginary line K2) of an imaginary circle C formed by connecting the centers of the balls 103 on the track 106. The scooping portion 33 is provided with a tongue 35 that scoops up the ball 103 from the track 106.

[0062] 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.

[0063] 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. 11A is a cross-sectional view taken along line XIA-XIA in Fig. 6. Fig. 11B is a cross-sectional view taken along line XIB-XIB in Fig. 6. Fig. 12 is a side view taken from the direction of arrow XII in Fig. 6.

[0064] 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. The first opposing surface 36 is provided with an opening 37, which is an entrance and exit for the ball passage 34. As shown in FIG. 10, the 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 openings 8a and 37 are round-chamfered (see FIGS. 2 and 10). Note that, in the present disclosure, the chamfering of the openings 8a and 37 may be square-chamfered instead of round-chamfered.

[0065] 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 square pillar shape. As shown in FIG. 6, the positioning protrusion 38 is inserted into the positioning hole 26.

[0066] As shown in Figures 11A and 11B, the positioning protrusion 38 has a tip surface 38a (not shown in Figure 11A, see Figure 11B) facing the first axial direction X1, a bottom surface 38b facing the second vertical direction Z2 toward the seating surface, and a pair of side surfaces 38c (not shown in Figure 11B, see Figure 11A) facing the seating surface direction.

[0067] As shown in FIG. 11A , a pair of side surfaces 38c of the positioning protrusion 38 abuts against a pair of opposing surfaces 26a of the positioning hole 26. Therefore, the middle deflector 30 is restricted from shifting from a predetermined assembly position in the first seating direction Y1 or the second seating direction Y2. The pair of side surfaces 38c and the pair of opposing surfaces 26a are linear in the vertical direction. That is, the pair of side surfaces 38c and the pair of opposing surfaces 26a are in surface contact with each other. This prevents the middle deflector 30 from tilting around the positioning protrusion 38. In the present disclosure, the pair of side surfaces 38c may have an interference with the pair of opposing surfaces 26a. That is, the positioning protrusion 38 may be sandwiched between the pair of opposing surfaces 26a. Alternatively, a small gap due to tolerance may exist between the pair of side surfaces 38c and the pair of opposing surfaces 26a. The pair of side surfaces 38c and the pair of opposing surfaces 26a are not limited to being linear. For example, the pair of side surfaces 38c may be arc-shaped and may be in line contact with the pair of opposing surfaces 26a. Even with such a shape, the middle deflector 30 will not shift in the seating direction from the predetermined assembly position.

[0068] 11B, 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.

[0069] 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 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.

[0070] 11A and 11B, 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 surface 38b and the bottom surface 26c. As a result, 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.

[0071] 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. This prevents the middle deflector 30 from being erroneously placed with the positioning protrusion 38 facing the second axial direction X2 (with the opening 37 facing the second axial direction) when the middle deflector 30 is placed in the first accommodating section 5.

[0072] 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.

[0073] 11B, 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.

[0074] As shown in FIG. 11B, 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. In other words, 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.

[0075] 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.

[0076] 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.

[0077] 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.

[0078] 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. 14). 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. 14).

[0079] 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.

[0080] 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.

[0081] 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.

[0082] As shown in FIGS. 8 and 9, the middle deflector 30 of this embodiment is formed by assembling two parts (an inner peripheral part 81 and an outer peripheral part 82) separated along a dividing plane 80. As shown in FIG. 7, the dividing plane 80 extends in the axial direction. When viewed from the axial direction, the dividing plane 80 is parallel to a tangent to the imaginary circle C (see imaginary line K2). In other words, the dividing plane 80 is inclined toward the first vertical direction Z1 as it extends toward the first bearing surface direction Y1. Hereinafter, of the two parts constituting the middle deflector 30, the one located on the inner peripheral side of the dividing plane 80 will be referred to as the inner peripheral part 81, and the one located on the outer peripheral side of the dividing plane 80 will be referred to as the outer peripheral part 82.

[0083] 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.

[0084] The dividing surface 80 overlaps the outer periphery side of the ball passage 34. For this reason, as shown in FIG. 11B , an inner dividing surface 83 of the inner part 81 is provided with an inner rolling surface 85, which is a C-shaped or U-shaped groove that opens in the first vertical direction Z1. On the other hand, an outer dividing surface 84 of the outer part 82 is flat. A part of the outer dividing surface 84 forms an outer rolling surface 86 that covers the inner rolling surface 85 from the first vertical direction Z1. Note that, because the outer dividing surface 84 is flat, the outer part 82 can be easily manufactured.

[0085] 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.

[0086] 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.

[0087] 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.

[0088] FIG. 13 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. 13, 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. 13) 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 checked whether the opening 37, instead of the positioning protrusion 38, faces the first axial direction X1.

[0089] Next, the middle deflector 30 is moved in the second vertical direction Z2 (see arrow A1 in FIG. 13 ) and inserted into the first storage section 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.

[0090] Fig. 14 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. 14, the amount of axial gap between the first rib 61 and the second rib 62 is L8.

[0091] 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.

[0092] The tip portion 123 has a tip surface 124 facing the second perpendicular direction Z2, a first pressing surface 125A facing the first axial direction X1, and a second pressing surface 125B 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.

[0093] The axial width of the first pressing surface 125A and the second pressing surface 125B gradually increases toward the first vertical direction Z1, reaching a maximum of L10. The maximum axial width L10 of the first pressing surface 125A and the second pressing surface 125B is greater than the separation distance L8 between the first rib 61 and the second rib 62.

[0094] 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. 14). As a result, although not particularly shown, the tip surface 124 is inserted between the first rib 61 and the second rib 62, with the first pressing surface 125A abutting against the first rib 61 and the second pressing surface 125B abutting 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.

[0095] 15 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. 15, the jig 120 is pressed in the second vertical direction Z2 until the tip 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 125A. Furthermore, the second rib 62 is crimped in the second axial direction X2 by the second pressing surface 125B.

[0096] The crimped portion of the first rib 61 is inclined toward the first recess 22a disposed in the first axial direction X1 to form 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 125A, 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.

[0097] 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 125B, 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.

[0098] 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.

[0099] Fig. 16 is a plan view of the crimping step of the first embodiment as viewed from the first vertical direction. As shown in Fig. 16, 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 forcibly crimped, the deflector body 31 may be deformed.

[0100] 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.

[0101] 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.

[0102] Fig. 17 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. 17, 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. 16) and the load acting on the second arm portion 52 (see arrow A4 in Fig. 16) are opposed to each other and offset each other. This prevents deformation of the positioning protrusion 38.

[0103] 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.

[0104] 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.

[0105] 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.

[0106] 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.

[0107] 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.

[0108] 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.

[0109] 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.

[0110] 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 component (middle deflector 30) that is assembled to the nut body 1. The nut body 1 includes a recess provided on the outer peripheral surface 4 of the nut body 1 and has a bow-shaped accommodation portion (first accommodation portion 5) when viewed from an axial direction parallel to the screw shaft 102, a seating surface 10 that forms the bottom surface of the accommodation portion, a through-hole 17 that penetrates the seating surface 10 and the inner peripheral surface 2 of the nut body 1, a pair of side surfaces 20 that are arranged on both axial sides of the accommodation portion (first accommodation portion 5) and face each other, and a return path 8 that extends in the axial direction. The direction parallel to the seating surface when viewed from the axial direction is the seating surface direction. The circulation component (middle deflector 30) includes a circulation component body (deflector body 31) disposed in the accommodation section and through-hole 17, and an arm portion 50 extending from the circulation component body toward the seating surface and abutting the seating surface. The pair of side surfaces 20 includes a first side surface 20a disposed on one side of the circulation component in the axial direction (first axial direction X1) and provided with an opening 8a of the return path 8, and a second side surface 20b disposed on the other side of the circulation component in the axial direction (second axial direction X2). The circulation component body (deflector body 31) includes a ball passage 34 through which the ball 103 rolls, a first opposing surface 36 provided with an opening 37 of the ball passage 34 and facing the first side surface 20a, and a second opposing surface 46 facing the second side surface 20b. At least one of the first side surface 20a and the second side surface 20b is provided with a positioning hole 26 recessed in the axial direction and opening to the outer peripheral surface 4 of the nut body 1. Positioning protrusions 38 to be inserted into the positioning holes 26 are provided on one or both of the first opposing surface 36 and the second opposing surface 46 that face the side surface 20 on which the positioning holes 26 are provided.

[0111] According to the first embodiment, the arm portion 50 and the positioning protrusion 38 position the middle deflector 30 without causing deviation from the predetermined assembly position in the bearing surface direction and the direction perpendicular to the bearing surface. Furthermore, the middle deflector 30 is positioned directly on the nut body 1 without using any other parts. This results in extremely high positioning accuracy. As a result, the ball 103 is smoothly transferred between the ball passage 34 and the return passage 8. Furthermore, the tongue 35 is positioned at a predetermined position, allowing the ball 103 to be smoothly scooped up.

[0112] In the first embodiment, the direction parallel to the perpendicular line (imaginary line K1) to the seat surface and in which the seat surface 10 faces is the first vertical direction Z1. The seat has ribs 60 that protrude from the arms 50 in the first vertical direction Z1 and extend along the side surfaces 20 toward the seat surface, and crimped portions 70 formed by crimping at least a portion of the rib 60 toward the side surfaces. The pair of side surfaces 20 are provided with recesses 22 that are grooves that extend toward the seat surface, face the ribs 60 in the axial direction, and into which the crimped portions 70 fit.

[0113] According to the first embodiment, the circulation part (middle deflector 30) does not come off from the nut body 1. Furthermore, a pin for fixing the circulation part (middle deflector 30) is not required, which prevents an increase in the number of parts.

[0114] 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.

[0115] 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.

[0116] 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.

[0117] 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.

[0118] Moreover, the seat surface 10 in the first embodiment is the edge portion 17a of the through hole 17, and has an extended seat surface 13 arranged in the axial direction relative to the through hole 17. The circulation part body (deflector body 31) has an extended seat surface 43 that abuts against the extended seat surface 13.

[0119] According to the first embodiment, the number of portions that come into contact with the seating surface 10 increases, further stabilizing the posture of the middle deflector 30. In addition, the inner peripheral side part 81 can be prevented from falling off into the through hole 17.

[0120] The ball screw device 100 of the first embodiment has been described above. The present disclosure may also be directed to a ball screw device in which the side of the outer circumferential surface of the scooping portion 33 of the middle deflector 30 facing the seating surface is abutted against the inner circumferential surface of the through hole 17, thereby positioning the middle deflector 30 in the seating surface direction. 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, between the second side surface 20b and the second opposing surface 46, or between both of them, due to tolerance considerations. If the gap between the first side surface 20a and the first opposing surface 36 were large, the 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. The following description will focus on changes from the first embodiment.

[0121] (Embodiment 2) Fig. 18 is a side view of the nut of embodiment 2 before the rib is crimped, as viewed from the second bearing surface direction. Fig. 19 is a side view of the nut of embodiment 2 after the rib is crimped, as 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.

[0122] 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. 14, 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. 14, etc.), a second crimped portion 72A is generated.

[0123] 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.

[0124] As described above, according to the second embodiment, the 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.

[0125] (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.

[0126] 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.

[0127] 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.

[0128] As described above, according to the third embodiment, the 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.

[0129] (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.

[0130] 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.

[0131] 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 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.

[0132] 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.

[0133] (Embodiment 5) 24 is a perspective view of a middle deflector 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 50D in the seating direction is longer than the length of the rib 60 in the seating direction. That is, the tip 50a of the arm 50D of the fifth embodiment protrudes outward in the seating direction beyond the tip 60b of the rib 60. This middle deflector 30D increases the contact area with the seat 10, making the posture of the middle deflector 30D more stable.

[0134] 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. 24, see FIGS. 11B 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 require the middle deflector 30D of the fifth embodiment to have an extended seating surface 43 (see FIG. 9).

[0135] 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.

[0136] (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.

[0137] 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.

[0138] 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.

[0139] The inclined surface 91 is inclined toward the first bearing 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 of the inner part 81E is provided with a C-shaped inner rolling surface 85 that opens in the first vertical direction Z1. The outer inclined surface 91b of the outer part 82E is provided with a C-shaped outer rolling surface 86 that opens in the second vertical direction Z2. Therefore, the inner divided surface 83E and the outer divided surface 84E each have a groove surface (the inner rolling surface 85 and the outer rolling surface 86). Therefore, the ball 103 rolls more smoothly in the ball passage 34 than in the first embodiment.

[0140] 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.

[0141] The inner peripheral part 81E of the sixth embodiment has a tongue 35 and an inner peripheral rolling surface 85. The outer peripheral part 82E has an outer peripheral rolling surface 86 and two arm portions 50.

[0142] As described above, the middle deflector 30E of the sixth embodiment has a crimped portion (not shown in FIGS. 25 and 26) similar to the first embodiment, and therefore does not shift in position in the first vertical direction Z1. Furthermore, even if the inner part 81E and the outer part 82E are disengaged from each other, the outer part 82E has two arms 50 and therefore does not shift in position in the vertical direction. On the other hand, although the inner part 81E does not have arms 50, the protrusion 95 is caught in the groove 96, and therefore does not shift in position in the second vertical direction Z2. In other words, the inner part 81E is prevented from falling into the through hole 17. Furthermore, the tongue 35 is integrally formed on the inner part 81E without being separated. Therefore, the strength of the tongue 35 is maintained, and the ball 103 is smoothly scooped up.

[0143] 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.

[0144] (Embodiment 7) FIG. 27 is a side view of the middle deflector of the seventh embodiment as viewed from the first axis 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. Furthermore, 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.

[0145] (Embodiment 8) Fig. 28 is a view of the middle deflector of embodiment 8 and its periphery viewed from the outer periphery side. Fig. 29 is a perspective view of the middle deflector of embodiment 8 before crimping viewed from the first axial direction. Fig. 30 is a view of the first side surface of embodiment 8 viewed from the second axial direction. Fig. 31 is a cross-sectional view taken along line XXXI-XXXI in Fig. 28.

[0146] As shown in FIG. 28 , the nut 101G of the eighth embodiment includes a middle deflector 130 and a nut body 1G, similar to the first embodiment. However, the middle deflector 130 of the eighth embodiment differs from the middle deflector 30 of the first embodiment in that it has a cylindrical protrusion 138 instead of the positioning protrusion 38. The nut body 1G of the eighth embodiment also differs from the nut body 1 of the first embodiment in that it has a cylindrical protrusion hole 126 instead of the positioning hole 26. Furthermore, the middle deflector 130 of the eighth embodiment differs from the other embodiments in that it does not have a dividing surface 80, as in the seventh embodiment, and is formed as a whole as an integral part. The integrated middle deflector 130 has been described in the seventh embodiment, so a description thereof will be omitted. The cylindrical protrusion 138 and the cylindrical protrusion hole 126 will be described below.

[0147] As shown in Figure 29, the middle deflector 130 has a cylindrical protrusion 138. The cylindrical protrusion 138G protrudes from the first opposing surface 36 in the first axial direction X1. The cylindrical protrusion 138 is cylindrical in shape. The internal space of the cylindrical protrusion 138 forms part of the ball passage 34. The cylindrical protrusion 138 has a tip surface 138a facing the first axial direction X1, a bottom surface 138b facing the seating surface direction in the second vertical direction Z2, and a pair of side surfaces 138c facing the seating surface direction. An opening of the ball passage 34 is provided in the tip surface 138a.

[0148] As shown in Figure 30, the cylindrical-projection hole 126 is a hole recessed from the first side surface 20a in the first axial direction X1. The cylindrical-projection hole 126 also opens toward the outer peripheral surface 4 of the nut body 1. The inner surface of the cylindrical-projection hole 126 has a pair of opposing surfaces 126a that sandwich the cylindrical-projection hole 126 from the seating surface direction, a side surface 126b that is disposed in the first axial direction X1 relative to the cylindrical-projection hole 126, and a bottom surface 126c that is disposed in the second vertical direction Z2 relative to the cylindrical-projection hole 126. An opening 8a of the return path 8 is provided in the side surface 126b.

[0149] 31, the cylindrical protrusion 138 is inserted into the cylindrical-protrusion hole 126. When viewed in the axial direction, the cylindrical protrusion 138 and the cylindrical-protrusion hole 126 have the same substantially rectangular shape. A pair of side surfaces 138c of the cylindrical protrusion 138 abut against a pair of opposing surfaces 126a of the cylindrical-protrusion hole 126. This prevents the middle deflector 130 from shifting from a predetermined assembly position in the first seating surface direction Y1 or the second seating surface direction Y2.

[0150] The pair of side surfaces 138c and the pair of opposing surfaces 126a are linear in the vertical direction. Therefore, the pair of side surfaces 138c and the pair of opposing surfaces 126a are in surface contact with each other. This prevents the middle deflector 130 from tilting around the cylindrical protrusion 138.

[0151] Furthermore, the ends of the cylindrical protrusion 138 and the cylindrical protrusion hole 126 in the second vertical direction Z2 are located further in the second vertical direction Z2 than the opening 8a of the return path 8 and the opening 37 of the ball passage 34. Therefore, the vertical lengths of the cylindrical protrusion 138 and the cylindrical protrusion hole 126 are greater than those of the positioning protrusion 38 and the positioning hole 26 of the first embodiment. That is, according to the eighth embodiment, the contact area between the pair of side surfaces 138c and the pair of opposing surfaces 126a is large. This further strengthens the middle deflector 130 to prevent it from shifting in position toward the seat surface or tilting around the cylindrical protrusion 138.

[0152] Furthermore, the cylindrical protrusion 138 and the cylindrical protrusion hole 126 have the same length in the seating surface direction. Therefore, the pair of side surfaces 138c do not have an interference with the pair of opposing surfaces 126a. Note that, in the present disclosure, the pair of side surfaces 138c may have an interference with the pair of opposing surfaces 126a. Alternatively, there may be a minute gap due to tolerance between the pair of side surfaces 138c and the pair of opposing surfaces 126a. Note that, in the present disclosure, the pair of side surfaces 138c and the pair of opposing surfaces 126a are not limited to being linear.

[0153] The bottom surface 138b of the cylindrical protrusion 138 and the bottom surface 126c of the cylindrical-protrusion hole are linear in the seating surface direction. The bottom surface 138b of the cylindrical protrusion 138 abuts against the bottom surface 126c of the cylindrical-protrusion hole. Therefore, the middle deflector 130 of the eighth embodiment is positioned in the vertical direction not only by the combination of the arm portion 50 and the seating surface 10 but also by the combination of the bottom surface 138b of the cylindrical protrusion 138 and the bottom surface 126c of the cylindrical-protrusion hole 126.

[0154] Although not specifically shown, a minute gap is provided between the tip surface 138a of the cylindrical protrusion 138 and the side surface 126b of the cylindrical protrusion hole 126. This allows the minute gap to absorb any manufacturing error even if the cylindrical protrusion 138 is manufactured to protrude more than the specified amount. This prevents the first side surface 20a and the first opposing surface 36 from separating, which would cause the tongue 35 to deviate from its specified position. On the other hand, a minute gap allows for smooth delivery of the ball 103.

[0155] According to the nut 101G of the eighth embodiment described above, the opening 37 of the ball passage 34 and the opening 8a of the return path 8 are provided in a positioning configuration (the cylindrical protrusion hole 126 and the cylindrical protrusion 138), resulting in high positioning accuracy. In other words, the opening 37 of the ball passage 34 and the opening 8a of the return path 8 have high coaxiality, which allows for smoother delivery of the ball 103.

[0156] As described above, in the nut 101G of the eighth embodiment, the first opposing surface 36 of the middle deflector 130 is provided with a cylindrical protrusion 138 whose interior forms part of the ball passage 34. The first side surface 20a of the nut body 1G is provided with a cylindrical protrusion hole 126 that is recessed in the axial direction, opens to the outer peripheral surface 4 of the nut body 1G, and into which the cylindrical protrusion 138 is inserted. The cylindrical protrusion 138 has an opening 37 of the ball passage 34 in a tip surface 138a of the side surface facing one side in the axial direction (first axial direction X1). The cylindrical protrusion hole 126 has an opening 8a of the return passage 8 in a side surface 126b of the inner surface facing the tip surface 138a.

[0157] According to the eighth embodiment, the cylindrical protrusion 138 abuts against the inner surface of the cylindrical protrusion hole 126, and the middle deflector 130 is positioned at a predetermined assembly position in the seating direction. Furthermore, the middle deflector 130 is positioned directly with respect to the nut body 1G without the need for any other components, resulting in high positioning accuracy. Furthermore, the opening 37 of the ball passage 34 and the opening 8a of the return passage 8 are provided in the positioning components (the cylindrical protrusion hole 126 and the cylindrical protrusion 138), resulting in high coaxiality. Therefore, the delivery of the ball 103 is performed more smoothly.

[0158] The eighth embodiment has been described above. The middle deflector 130 of the eighth embodiment has an arm portion 50 that abuts against the seat surface 10, and is positioned at a predetermined assembly position in the vertical direction. Therefore, in the present disclosure, the bottom surface 138b of the cylindrical protrusion 138 does not need to abut against the bottom surface 126c of the cylindrical-protrusion hole 126. In other words, a gap (see gap S11 in FIGS. 11A and 11B) for absorbing manufacturing errors may be provided between the bottom surface 138b of the cylindrical protrusion 138 and the bottom surface 126c of the cylindrical-protrusion hole.

[0159] In addition, in the present embodiment, a minute gap is provided between the tip surface 138a of the cylindrical protrusion 138 and the side surface 126b of the cylindrical protrusion hole 126, but in the present disclosure, the tip surface 138a and the side surface 126b may be brought into contact with each other to perform axial positioning. Furthermore, the gap provided between the tip surface 138a of the cylindrical protrusion 138 and the side surface 126b of the cylindrical protrusion hole 126 does not need to be minute as long as smooth transfer of the ball 103 can be ensured.

[0160] Furthermore, while the middle deflector 130 of the eighth embodiment has been described as being integrally formed as a whole, the present disclosure may also be applicable to a deflector consisting of two parts (an inner peripheral part and an outer peripheral part) as shown in the first and sixth embodiments. Furthermore, in the case of a deflector consisting of two parts (an inner peripheral part and an outer peripheral part), the cylindrical projections may be provided separately on the inner peripheral part and the outer peripheral part, respectively. This allows the inner peripheral part and the outer peripheral part to be positioned in the bearing surface direction. Next, a nut 101H of a ninth embodiment will be described.

[0161] (Embodiment 9) Fig. 32 is a view of the middle deflector of embodiment 9 and its periphery viewed from the outer periphery side. Fig. 33 is a perspective view of the middle deflector of embodiment 9 before crimping, viewed from the first axial direction. Fig. 34 is a perspective view of the nut body of embodiment 9, viewed from the second axial direction. Fig. 35 is a cross-sectional view taken along line XXXI-XXXI in Fig. 32. Fig. 36 is a cross-sectional view taken along line XXXVI-XXXVI in Fig. 32. Fig. 37 is a cross-sectional view taken along line XXXVII-XXXVII in Fig. 32.

[0162] As shown in FIG. 32, the nut 101H of the ninth embodiment includes a middle deflector 230 and a nut body 1H, similar to the first embodiment. However, the middle deflector 230 of the ninth embodiment differs from the middle deflector 30 of the first embodiment in that it further includes a cylindrical protrusion 238 in addition to the positioning protrusion 38. The nut body 1H of the ninth embodiment also differs from the nut body 1 of the first embodiment in that it includes a cylindrical protrusion hole 226 in addition to the positioning hole 26. The nut body 1H of the ninth embodiment differs from the nut body 1 of the first embodiment in that it is provided with a through-hole 240. The middle deflector 230 of the ninth embodiment differs from the middle deflector 30 of the first embodiment in that it is provided with a hole 250. Furthermore, the nut 03 of the ninth embodiment differs from the nut 101 of the first embodiment in that it includes a pin 260. The differences will be explained below.

[0163] As shown in FIG. 33, the middle deflector 230 includes a cylindrical protrusion 238. The cylindrical protrusion 238 is a protrusion that protrudes from the first opposing surface 36 in the first axial direction X1. The cylindrical protrusion is provided on an inner peripheral component. The cylindrical protrusion 238 is cylindrical. The internal space of the cylindrical protrusion 238 forms a part of the ball passage 34. The cylindrical protrusion 238 has a tip surface (second surface) 238a that faces the first axial direction X1. An opening 37 of the ball passage 34 is provided in the tip surface 238a.

[0164] The outer peripheral surface 239 of the cylindrical projection 238 has a circular shape with the center of the opening 37 of the ball passage 34 as a reference. The cylindrical projection 238 has a wall portion cut out from the internal space in the first vertical direction Z1. Therefore, the outer peripheral surface 239 of the cylindrical projection 238 has a C-shape when viewed from the axial direction, and faces the first seating surface direction, the second seating surface direction, and the second vertical direction. Note that, in the present disclosure, a projection that covers the first vertical direction of the cylindrical projection 238 may be provided on the outer peripheral part.

[0165] As shown in FIG. 34, the cylindrical-projection hole 226 is a hole recessed from the first side surface 20a in the first axial direction X1. The cylindrical-projection hole 226 also opens toward the outer peripheral surface 4 of the nut body 1. As shown in FIG. 35, the inner surface of the cylindrical-projection hole 226 has a pair of opposing surfaces 226a that sandwich the cylindrical-projection hole 226 from the seating surface direction, a side surface 226b that is disposed in the first axial direction X1 relative to the cylindrical-projection hole 226, and a bottom surface 226c that is disposed in the second vertical direction Z2 relative to the cylindrical-projection hole 226. An opening 8a of the return path 8 is provided in the side surface 226b. The bottom surface 226c has a circular shape (arcuate shape) with the center O8 of the return path 8 as the reference.

[0166] As shown in Fig. 35, the cylindrical protrusion 238 is inserted into the cylindrical protrusion hole 226. A portion of the outer peripheral surface 239 of the cylindrical protrusion 238 facing the seating surface direction (see points 239a and 239b in Fig. 35) abuts against the pair of opposing surfaces 226a. This prevents the middle deflector 230 from shifting from a predetermined assembly position in the first seating surface direction Y1 or the second seating surface direction Y2.

[0167] An arc-shaped portion of the outer circumferential surface 239 of the cylindrical protrusion 238 facing the second seating surface direction Y2 (see the portion between points 239a and 239b in FIG. 35) abuts against the bottom surface 226c of the cylindrical-protrusion hole 226. Therefore, the middle deflector 230 of the ninth embodiment is vertically positioned not only by the combination of the arm portion 50 and the seating surface 10, but also by the combination of the outer circumferential surface 239 of the cylindrical protrusion 238 and the bottom surface 226c of the cylindrical-protrusion hole 226. Furthermore, the abutting portions (the outer circumferential surface 239 and the bottom surface 226c) have an arc-shaped shape. This provides a high degree of coaxiality between the opening 37 of the ball passage 34 and the opening 8a of the return passage 8. This allows for smooth delivery of the ball 103.

[0168] Although not specifically shown, the tip surface 238a of the cylindrical protrusion 238 abuts against the side surface 226b of the cylindrical protrusion hole 226. Therefore, the opening 37 of the ball passage 34 and the opening 8a of the return path 8 are continuous (adjacent) in the axial direction without any gap, allowing for smooth delivery of the ball 103.

[0169] In addition, in the ninth embodiment, similar to the eighth embodiment, the opening 37 of the ball passage 34 and the opening 8a of the return path 8 are provided with a positioning configuration (the cylindrical protrusion hole 226 and the cylindrical protrusion 238). Therefore, the opening 37 of the ball passage 34 and the opening 8a of the return path 8 have a high degree of coaxiality, which allows for smoother delivery of the ball 103.

[0170] As shown in Fig. 34, the through hole 240 is a circular hole that axially penetrates the other end face 241 and the second side face 20b of the nut body 1G. As shown in Fig. 36, the through hole 240 has the same diameter as the cylindrical-projection hole 226 and is coaxial with it. Therefore, when a cutting tool (not shown) is applied to the other end face 241 from the second axial direction X2 to form the through hole 240, the cylindrical-projection hole 226 can also be formed at the same time.

[0171] The hole 250 of the middle deflector 230 is a recess provided in the second opposing surface 46. As shown in FIG. 37, the hole 250 is provided in the inner peripheral part 81. The hole 250 has a circular shape at the center O8 of the return path 8. Therefore, as shown in FIG. 36, the hole 250 is adjacent to the through hole 240 in the axial direction.

[0172] The pin 260 has a cylindrical shape. The pin 260 is inserted into the through-hole 240 and fits into the inner circumferential surface of the through-hole 240. A protrusion 261 that protrudes in the first axial direction X1 is provided on an end face of the pin 260 in the first axial direction X1. The protrusion 261 is inserted into the hole 250 of the middle deflector 230. As shown in FIG. 37 , the protrusion 261 has a circular shape and abuts against the inner surface of the hole 250. As a result, when a load acts on the middle deflector 230 in the vertical direction and the bearing surface direction, the inner surface of the hole 250 catches on the protrusion 261, and displacement of the middle deflector 230 is suppressed.

[0173] 32, the cylindrical protrusion 238 and the hole 250 are provided on the inner peripheral side component 81. On the other hand, the positioning protrusion 38 is provided on the outer peripheral side component 82. Therefore, even if the joining between the inner peripheral side component 81 and the outer peripheral side component 82 is released, they will not become misaligned.

[0174] As described above, the nut body 1H of embodiment 9 has the other end face 241 facing the other axial direction, and a through hole 240 that penetrates the other end face 241 and the second side face 20b in the axial direction and is coaxial with the return path 8.

[0175] According to the through hole 240 described above, a cutting tool (not shown) can be inserted into the through hole 240 from the second axis direction X2 of the other end surface 241, and the tip of the cutting tool can be brought into contact with the first side surface 20a to perform cutting. This makes it easy to form the return path 8 on the first side surface 20a.

[0176] Furthermore, the second opposing surface 46 of the middle deflector 230 of the ninth embodiment is recessed on one side in the axial direction and provided with a hole 250 adjacent to the through hole 240 in the axial direction. A pin 260 is inserted into the through hole 240. One axial end of the pin 260 is inserted into the hole 250.

[0177] According to the above configuration, when a load acts on the middle deflector 230 in the vertical direction and the bearing surface direction, the inner surface of the hole 250 catches on the protrusion 261, and displacement of the middle deflector 230 is suppressed.

[0178] In the ninth embodiment, the pin 260 is fitted into the through-hole 240 .

[0179] According to this configuration, the pin 260 does not come off the through-hole 240 .

[0180] In the ninth embodiment, the axial position of the pin 260 fitted into the through-hole 240 may be disposed closer to the first axial direction X1 so as to apply a load that presses the middle deflector 230 in the first axial direction X1. This allows the first opposing surface 36 of the middle deflector 230 to come into contact with the first side surface 20a (or the tip surface 238a and the side surface 226b) of the first accommodating portion 5, thereby facilitating the transfer of the ball 103.

[0181] Furthermore, in the ninth embodiment, the middle deflector 230 is fixed by two components, the crimping portion 70 and the pin 260. However, in the present disclosure, the middle deflector 230 may be fixed by only one of the crimping portion 70 and the pin 360. When the middle deflector 230 is fixed by the crimping portion 70, the pin 260 is not inserted into the through-hole 240, leaving the through-hole 240 hollow. Although the pin 260 is fitted into the through-hole 240, the method for fixing the pin 260 is not limited thereto. For example, the pin 260 may be fixed by adhesive or by fitting the protrusion 261 into the hole 250. Furthermore, although the cylindrical protrusion 238 in the ninth embodiment has a cutout and is C-shaped, it may also be cylindrical and is not particularly limited thereto. Furthermore, in the present disclosure, the outer diameter of the pin 260 is not limited to being the same as the inner diameter of the through-hole 240 into which it is fitted. For example, the outer diameter of pin 260 may be larger than the inner diameter of through hole 240, and pin 260 may have an interference. Alternatively, there may be a small gap due to tolerance between the outer peripheral surface of pin 260 and the inner peripheral surface of through hole 240. Furthermore, pin 260 may be a spring pin.

[0182] 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.

[0183] 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.

[0184] 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.

[0185] 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.

[0186] The present disclosure may also be implemented as a combination of the following configurations. (1) The nut body has a cylindrical nut body that is inserted into a screw shaft, and a circulatory component that is assembled to the nut body. The nut body has a recess provided on the outer peripheral surface of the nut body, an accommodating portion that is arch-shaped when viewed from an axial direction parallel to the screw shaft, a seat that forms the bottom surface of the accommodating portion, a through hole that penetrates the seating surface and the inner peripheral surface of the nut body, a pair of side surfaces that are arranged on both sides of the accommodating portion in the axial direction and that face each other, and a return path that extends in the axial direction. The direction that is parallel to the seating surface when viewed from the axial direction is the seating surface direction. The circulatory component has a circulatory component main body that is inserted into the accommodating portion and the through hole, and an arm portion that extends from the circulatory component main body in the seating surface direction and abuts against the seating surface. The nut has a first side that is positioned on one side of the axial direction relative to the circulating part and has an opening for the return path, and a second side that is positioned on the other side of the axial direction relative to the circulating part, and the circulating part body has a ball passage in which balls roll, a first opposing surface that is positioned on the other side of the axial direction relative to the circulating part and has an opening for the ball passage, and a second opposing surface that is positioned on the other side of the circulating part, and at least one of the first side and the second side has a positioning hole that is recessed in the axial direction and opens onto the outer peripheral surface of the nut body, and one or both of the first opposing surface and the second opposing surface that faces the side with the positioning hole is provided with a positioning protrusion that is inserted into the positioning hole. (2) The nut body has a cylindrical shape and is inserted into a screw shaft, and a circulatory component assembled to the nut body. The nut body has a recess provided on the outer peripheral surface of the nut body, an accommodating portion that is arch-shaped when viewed from an axial direction parallel to the screw shaft, a seating surface that forms the bottom surface of the accommodating portion, a through hole that penetrates the seating surface and the inner peripheral surface of the nut body, a pair of side surfaces that are arranged on both sides of the accommodating portion in the axial direction and that face each other, and a return path that extends in the axial direction. The direction that is parallel to the seating surface when viewed from the axial direction is the seating surface direction. The circulatory component has a circulatory component main body that is arranged in the accommodating portion and the through hole, and an arm portion that extends from the circulatory component main body in the seating surface direction and abuts against the seating surface. The pair of side surfaces form the circulatory component. 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 circulating part body has a ball passage in which balls roll, a first opposing surface facing the first side surface, and a second opposing surface facing the second side surface; the first opposing surface has a cylindrical protrusion whose interior is part of the ball passage; the first side surface has a cylindrical protrusion hole that is recessed in the axial direction and opens into the outer peripheral surface of the nut body, and into which the tubular protrusion is inserted; the tip surface of the side of the cylindrical protrusion facing one side of the axial direction has an opening for the ball passage; and the side of the cylindrical protrusion hole that faces the tip surface has an opening for the return path. (3) A nut as described in (2), wherein at least one of the first side surface and the second side surface is provided with a positioning hole recessed in the axial direction and opening onto the outer peripheral surface of the nut body, and one or both of the first opposing surface and the second opposing surface that faces the side surface on which the positioning hole is provided is provided with a positioning protrusion that is inserted into the positioning hole. (4) The circulating part is in a direction perpendicular to the seat surface, and the direction in which the seat surface faces is a first vertical direction, and has a rib protruding from the arm portion in the first vertical direction and extending along the side surface toward the seat surface, and 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 grooves extending toward the seat surface, facing the rib in the axial direction, and recesses into which the crimped portion fits.A nut described in any one of (1) to (3). (5) 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. (4) A nut as described in. (6) The rib has a first rib extending along the first side surface and a second rib extending along the second side surface, and the crimped portion has a first crimped portion that is part of the first rib and is crimped toward the first side surface, and a second crimped portion that is part of the second rib and is crimped toward the second side surface. (4) A nut as described in (5). (7) The nut according to (6), wherein the thickness of the second rib in the axial direction is smaller than the thickness of the first rib in the axial direction. (8) The nut according to (6) or (7), wherein the first rib faces the other side of the axial direction and has a first crimping surface that is crimped when generating the first crimped portion, and the first crimping surface is inclined so as to approach the first side surface as it moves in the first vertical direction. (9) The nut body has another end face facing the other side in the axial direction, and a through hole that penetrates the other end face and the second side face in the axial direction and is coaxial with the return path. A nut described in any one of (1) to (8). (10) The nut described in (9) above, wherein the second opposing surface is recessed on one side in the axial direction and has a hole adjacent to the through hole in the axial direction, a pin is inserted into the through hole, and one end of the pin in the axial direction is inserted into the hole. (11) The nut according to (10), wherein the pin is fitted into the through hole. (12) A nut described in any one of (1) to (11), wherein the second opposing surface has at least one protrusion that protrudes in the other axial direction and abuts against the second side surface, and the protrusion is crushed between the circulation part body and the second side surface. (13) A nut described in any one of (1) to (12), wherein the seating surface is an edge portion of the through hole and has an extended seating surface arranged in the axial direction relative to the through hole, and the circulation part body has an extended seating surface abutting the extended seating 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]

[0187] 1, 1G, 1H 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 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, 130, 230 Middle deflector (circulation device) 31 Deflector body (circulation part body) 32 Main body 33 Scooping section 34 Ball Passage 36 First opposing surface 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 Inner parts 82, 82E Outer periphery parts 83, 83E Inner peripheral side dividing surface 84, 84E Outer peripheral division surface 85 Inner rolling surface 86 Outer circumferential rolling surface 87 Step surface 88 End face 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, 101G, 101H nuts 102 screw shaft 103 Ball 120 Jig 126b, 226b side 126, 226 Cylindrical protrusion hole 138, 238 cylindrical projection 138a, 238a Tip surface 240 through holes 250 holes 260 pins 261 Convex

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 A recess provided on the outer peripheral surface of the nut body, the recess having a bow shape when viewed from an axial direction parallel to the screw axis; a seat surface forming a bottom surface of the storage portion; a through hole penetrating the seat surface and the inner peripheral surface of the nut body; a pair of side surfaces that are arranged on both sides of the accommodation portion in the axial direction and that face each other; a return path extending in the axial direction; and A direction parallel to the seat surface when viewed from the axial direction is a seat surface direction, 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 toward the seat surface and abutting against the seat surface; and The pair of side surfaces are a first side surface disposed on one side of the circulation component in the axial direction and having an opening for the return path; a second side surface disposed on the other side of the circulation component in the axial direction; and The circulating part body is a ball passage in which the ball rolls; a first opposing surface, the first opposing surface being provided with an opening for the ball passage and facing the first side surface; a second opposing surface opposing the second side surface; and At least one of the first side surface and the second side surface is provided with a positioning hole recessed in the axial direction and opening onto the outer peripheral surface of the nut body, a positioning protrusion to be inserted into the positioning hole is provided on one or both of the first opposing surface and the second opposing surface that faces the side surface on which the positioning hole is provided; The nut body is another end surface facing the other side in the axial direction; a through hole that axially penetrates the other end surface and the second side surface and is coaxial with the return path; have 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 A recess provided on the outer peripheral surface of the nut body, the recess having a bow shape when viewed from an axial direction parallel to the screw axis; a seat surface forming a bottom surface of the storage portion; a through hole penetrating the seat surface and the inner peripheral surface of the nut body; a pair of side surfaces that are arranged on both sides of the accommodation portion in the axial direction and that face each other; a return path extending in the axial direction; and A direction parallel to the seat surface when viewed from the axial direction is a seat surface direction, 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 toward the seat surface and abutting against the seat surface; and 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 circulating part body is a ball passage in which the ball rolls; a first opposing surface opposing the first side surface; a second opposing surface opposing the second side surface; and a cylindrical projection having an interior that forms a part of the ball passage is provided on the first opposing surface; The first side surface is provided with a cylindrical protrusion hole that is recessed in the axial direction, opens to the outer peripheral surface of the nut body, and into which the cylindrical protrusion is inserted, an opening of the ball passage is provided on a tip end surface of the side surface of the cylindrical projection that faces one side in the axial direction; An opening of the return path is provided on the side of the inner surface of the cylindrical projection hole that faces the tip end surface. nut.

3. At least one of the first side surface and the second side surface is provided with a positioning hole recessed in the axial direction and opening onto the outer peripheral surface of the nut body, One or both of the first and second opposing surfaces that face the side surface on which the positioning hole is provided is provided with a positioning protrusion that is inserted into the positioning hole. The nut according to claim 2.

4. The circulating part is a direction perpendicular to the seat surface and in which the seat surface faces is a first vertical direction; 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 that are grooves extending in the seating surface direction, that face the ribs in the axial direction, and that receive the crimped portions. The nut according to any one of claims 1 to 3.

5. 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 nut according to claim 4.

6. 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.

7. The thickness of the second rib in the axial direction is smaller than the thickness of the first rib in the axial direction. The nut according to claim 6.

8. the first rib has a first crimping surface facing the other side of the axial direction and crimped when generating the first crimped portion; The first crimping surface is inclined so as to approach the first side surface as it extends in the first perpendicular direction. The nut according to claim 6.

9. The nut body is another end surface facing the other side in the axial direction; a through hole that axially penetrates the other end surface and the second side surface and is coaxial with the return path; have The nut according to claim 2.

10. The second opposing surface is recessed toward one side in the axial direction and is provided with a hole adjacent to the through hole in the axial direction, A pin is inserted into the through hole, One end of the pin in the axial direction is inserted into the hole. The nut according to claim 1 or claim 9.

11. The pin is fitted into the through hole. The nut according to claim 10.

12. The second opposing surface is provided with at least one protrusion that protrudes toward the other side in the axial direction and abuts against the second side surface, The protrusion is crushed between the circulatory component body and the second side surface. The nut according to claim 1 or 2.

13. the seating surface is an edge of the through hole and has an expanded seating surface disposed in the axial direction relative to the through hole; The circulable part body has an extended seating surface that abuts against the extended seating surface. The nut according to claim 1 or 2.

14. Nut and a screw shaft that passes through the nut; a plurality of balls disposed between the nut and the screw shaft; Equipped with The nut is 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 A recess provided on the outer peripheral surface of the nut body, the recess having a bow shape when viewed from an axial direction parallel to the screw axis; a seat surface forming a bottom surface of the storage portion; a through hole penetrating the seat surface and the inner peripheral surface of the nut body; a pair of side surfaces that are arranged on both sides of the accommodation portion in the axial direction and that face each other; a return path extending in the axial direction; and A direction parallel to the seat surface when viewed from the axial direction is a seat surface direction, 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 toward the seat surface and abutting against the seat surface; and The pair of side surfaces are a first side surface disposed on one side of the circulation component in the axial direction and having an opening for the return path; a second side surface disposed on the other side of the circulation component in the axial direction; and The circulating part body is a ball passage in which the ball rolls; a first opposing surface, the first opposing surface being provided with an opening for the ball passage and facing the first side surface; a second opposing surface opposing the second side surface; and At least one of the first side surface and the second side surface is provided with a positioning hole recessed in the axial direction and opening onto the outer peripheral surface of the nut body, a positioning protrusion to be inserted into the positioning hole is provided on one or both of the first opposing surface and the second opposing surface that faces the side surface on which the positioning hole is provided; The nut body is another end surface facing the other side in the axial direction; a through hole that axially penetrates the other end surface and the second side surface and is coaxial with the return path; have Ball screw device.

15. Nut and a screw shaft that passes through the nut; a plurality of balls disposed between the nut and the screw shaft; Equipped with The nut is 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 A recess provided on the outer peripheral surface of the nut body, the recess having a bow shape when viewed from an axial direction parallel to the screw axis; a seat surface forming a bottom surface of the storage portion; a through hole penetrating the seat surface and the inner peripheral surface of the nut body; a pair of side surfaces that are arranged on both sides of the accommodation portion in the axial direction and that face each other; a return path extending in the axial direction; and A direction parallel to the seat surface when viewed from the axial direction is a seat surface direction, 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 toward the seat surface and abutting against the seat surface; and 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 circulating part body is a ball passage in which the ball rolls; a first opposing surface opposing the first side surface; a second opposing surface opposing the second side surface; and a cylindrical projection having an interior that forms a part of the ball passage is provided on the first opposing surface; The first side surface is provided with a cylindrical protrusion hole that is recessed in the axial direction, opens to the outer peripheral surface of the nut body, and into which the cylindrical protrusion is inserted, an opening of the ball passage is provided on a tip end surface of the side surface of the cylindrical projection that faces one side in the axial direction; An opening of the return path is provided on the side of the inner surface of the cylindrical projection hole that faces the tip end surface. Ball screw device.

Images