BALL DRIVE

Abstract

A ball screw drive of the present disclosure comprises a nut, a lead screw, several balls, and at least one redirection that circulates the balls. An outer circumferential surface of the lead screw is provided with at least one recess that is radially recessed inwards and accommodates the redirection. On an inner circumferential surface of the recess, two lead screw openings are provided in an outer circumferential raceway, and the lead screw openings are open towards the redirection. The redirection comprises a pair of redirection openings that open in an outer circumferential surface of the redirection and are connected to the lead screw openings, a circumferential groove surface that is connected to each of the two redirection openings and has an interior space that forms a circumferential path, and a pair of tongues that are arranged radially outside the circumferential groove surface and project towards the redirection openings.One tip of the tongue is arranged radially outside a virtual spiral that connects the centers of the multiple balls rolling on the track.

Description

Area

[0001] The present disclosure relates to a ball screw drive. background

[0002] A ball screw drive comprises a nut, a lead screw inserted into the nut, several balls arranged between the nut and the lead screw, and a recirculating component. An inner circumferential raceway is formed on an inner surface of the nut. An outer circumferential raceway, opposite the inner circumferential raceway, is formed on an outer surface of the lead screw. A helical raceway is formed between the inner and outer circumferential raceways. The several balls are arranged on this raceway and move helically along it. The recirculating component then returns the ball, which has moved from one end of the raceway to the other, to one end of the raceway. An example of a recirculating component is a deflector that returns the balls around a projection.

[0003] In a ball screw drive, as described in the following patent literature, a recess is formed on the outer circumferential surface of the spindle screw, which is radially recessed inwards. The redirector is inserted into the recess and fastened to the spindle screw. The redirector has a radially outward-facing outer diameter surface and a circumferential groove surface that extends radially inwards from the outer diameter surface. The circumferential groove surface is an S-shaped groove, which, viewed from the radial outside, has an S-shape. The ball moves radially inwards within the S-shaped groove surface of the redirector and slides over the thread of a nut. Citation list for patent literature

[0004] Patent Literature 1: JP 2004-225770 A Summary: Technical Task

[0005] However, in the deflector described in the aforementioned patent literature, the ball, when moving radially inwards, can become trapped between the S-shaped groove surface (circulating groove surface) and the inner circumferential running surface of the nut. Therefore, smooth rolling of the ball is not guaranteed. Furthermore, if the ball becomes trapped, a groove shoulder of the S-shaped groove surface (circulating groove surface) can be damaged.

[0006] The present disclosure was made in consideration of the above, and one objective of the present disclosure is to provide a ball screw drive capable of rolling balls smoothly and preventing deflection breakage. Solution to the task

[0007] A ball screw drive according to one embodiment of the present disclosure comprises: a nut having an inner circumferential raceway on an inner circumferential surface; a screw inserted into the nut having an outer circumferential raceway on an outer circumferential surface; several balls arranged on a raceway between the outer circumferential raceway and the inner circumferential raceway; and at least one deflector that circulates the several balls. The outer circumferential surface of the screw is provided with at least one recess that extends radially inward and accommodates the deflector. The recess has an inner circumferential surface that is provided with two screw openings in the outer circumferential raceway, the two screw openings being open toward the deflector.The deflector comprises: a pair of deflector openings that open in an outer circumferential surface of the deflector and are connected to the two spindle screw openings; a circumferential groove surface connected to each of the two deflector openings and having an interior that forms a circumferential path; and a pair of tongues that are arranged radially outside the circumferential groove surface and project in the direction of the pair of deflector openings. Each pair of tongues has a tip that is arranged radially outside a virtual spiral that connects the centers of the multiple balls rolling on the raceway.

[0008] According to the present disclosure, a ball that has entered a deflection opening from an outer circumferential raceway comes into contact with a tongue tip. The tip of the tongue is in contact with a portion of the ball on a radially outer side of the ball's center. As a result, the ball's path changes to a radially inner side, and the ball reliably moves radially inward. This prevents the ball from becoming jammed between the circumferential groove surface and the inner circumferential raceway of the nut, ensuring smooth rolling of the ball. Furthermore, it prevents fracture of the groove shoulder of the circumferential groove surface.

[0009] In a preferred aspect of the ball screw drive described above, each pair of tongues has a radially inward-facing inner surface. The inner surface is inclined such that it gradually points radially inward with increasing distance from the tip.

[0010] According to the configuration above, after the ball comes into contact with the tip of the tongue, it is guided radially inwards along an inclined surface. Therefore, the ball moves smoothly radially inwards.

[0011] In a preferred embodiment of the ball screw drive described above, the tip is arranged on the inner circumferential running surface of the nut.

[0012] According to the configuration above, the distance between the tongue tip and the inner circumferential running surface is small. Therefore, the ball is prevented from being caught by the tip of the tongue (movement stopped).

[0013] Furthermore, the circumferential groove surface of the ball screw drive described above is an S-shaped groove surface. The S-shaped groove surface comprises: a helical section located near each of the two deflection openings and extending along a spiral direction corresponding to the raceway, and a curved section adjacent to the helical section that gradually deviates from the spiral direction. The apex of the curved section is located radially outward with respect to the helical section.

[0014] Furthermore, the circumferential groove surface of the ball screw drive described above is an S-shaped groove surface. The S-shaped groove surface comprises: a helical section located near each of the two deflection openings and extending along a spiral direction corresponding to the raceway, and a curved section adjacent to the helical section that gradually deviates from the spiral direction. The apex of the curved section is located radially outward.

[0015] In a preferred aspect of the ball screw drive described above, the circumferential groove surface is an S-shaped groove surface. Viewed from the radial outside of the spindle screw, the recess and the deflection in a cutting direction that intersects an axial direction have a length that is greater than a length in the axial direction parallel to the spindle screw.

[0016] According to the configuration above, the ratio of the S-shaped groove area increases in one direction of intersection. In other words, the degree of curvature of the S-shaped groove surface becomes smoother. Therefore, the ball moves smoothly on the S-shaped groove surface.

[0017] Furthermore, the circumferential groove surface of the ball screw drive described above extends in a reverse spiral direction, which is opposite to the spiral direction in which the raceway extends.

[0018] In a preferred aspect of the ball screw drive described above, the outer circumferential running surface has a thread height that is greater than the thread height of the inner circumferential running surface.

[0019] According to the configuration above, it is difficult for the ball to ride on the groove shoulder of the outer circumferential raceway because the height of a screw thread on the outer circumferential raceway increases. Furthermore, according to the configuration above, the bottom of the outer circumferential raceway is deep. Therefore, when the ball moves from the outer circumferential raceway to the circumferential groove surface of the redirector, the step (amount of radial movement) between the outer circumferential raceway and the circumferential groove surface of the redirector is small. On the other hand, when the redirector is provided in the nut, the bottom of the inner circumferential raceway is shallow, so the step (amount of radial movement) between the inner circumferential raceway and the circumferential groove surface of the redirector is large. Therefore, according to the present disclosure, the radial movement of the ball is suppressed, and the ball moves frictionlessly on the circumferential groove surface.

[0020] In a preferred aspect of the ball screw drive described above, the circumferential groove surface further comprises: a pair of inlet / outlet groove surfaces arranged at both ends in an extension direction of the circumferential groove surface, wherein the pair of inlet / outlet groove surfaces extends circumferentially from the pair of deflection openings, and a concave surface in which the multiple balls sink radially inwards, wherein the concave surface is arranged between the pair of inlet / outlet groove surfaces.

[0021] According to the configuration above, the ball rolling on an inlet / outlet groove surface abuts the inner circumferential running surface of the nut when a radially outward load acts on the deflector. Therefore, radial outward movement of the deflector is restricted, and the deflector can be prevented from disengaging from the recess.

[0022] In a preferred aspect of the ball screw drive described above, the circumferential groove surface encloses a concave area in which the multiple balls sink radially inwards. The concave area is linear in the axial direction.

[0023] In a conventional concave surface, viewed axially, a concave shape is formed, with the central portion being more deeply recessed radially inwards in the S-shaped direction than both ends in the S-shaped direction in which the concave surface extends. Furthermore, since the concave surface of the above configuration is linear in the axial direction, the angle of deflection upon entry of the ball into the concave surface is small. Therefore, the rolling of the ball is frictionless.

[0024] In a preferred aspect of the ball screw drive described above, the pair of deflection openings has a groove shape that is larger than the groove shape of the two spindle screw openings.

[0025] According to the configuration above, one edge of the deflector opening does not move into a spindle screw opening, even if the deflector moves radially outward. Therefore, contact between the edge of the deflector opening and the ball is prevented. Advantageous effects of the invention

[0026] In the ball screw drive of the present disclosure, smooth rolling of the ball is ensured. Furthermore, breakage of the groove shoulder of the circumferential groove surface is prevented. Brief description of the drawings Fig. Figure 1 is a cross-sectional view of a brake caliper according to one embodiment. Fig. Figure 2 is a perspective view of a deflector and a recess of a ball screw drive according to this embodiment. Fig. Figure 3 is an enlarged view of the radial outside of the recess and deflector according to the embodiment. Fig. Figure 4 is a cross-sectional view, schematically showing a cross-section along the center of an S-shaped grooved surface. Fig. Figure 5 is a diagram showing an opening (threaded screw opening) on ​​an outer circumferential running surface, as seen from the recess, which is provided on a second opposite surface of the recess. Fig. 6 is a diagram showing a state in which the deflector moves from one state to Fig. 5 radially outwards. Fig. 7 is an enlarged view showing part of the depression and deflector on the lower left. Fig. 3 is enlarged. Fig. Figure 8 is a cross-sectional view along line VIII-VIII in the Fig. 7. Fig. Figure 9 is a cross-sectional view of a ball screw drive of comparison example 1, taken along a central section of a groove width of an S-shaped groove surface. Fig. Figure 10 is a diagram that represents a deflector of comparison example 2 in an abstract way. Fig. Figure 11 is a schematic representation of the deflector according to the exemplary embodiment in an abstract manner. Fig. Figure 12 is a schematic representation of a deflector according to modification 1, viewed from the radial outside. Fig. Figure 13 is a schematic cross-sectional view of a deflector according to modification 2 along a circumferential groove surface. Fig. Figure 14 is a schematic cross-sectional view of a deflector according to modification 3 along a circumferential groove surface. Fig. Figure 15 is a schematic cross-sectional view of a deflector according to modification 4 along a circumferential groove surface. Fig. Figure 16 is a schematic view of a deflector according to modification 5 as seen from the radial outside. Fig. Figure 17 is a schematic view of a deflector according to modification 6 as seen from the radial outside. Description of the embodiments

[0027] The present disclosure is described in detail below with reference to the drawings. It should be noted that the present invention is not limited to the following embodiment (hereinafter referred to as the embodiment) for carrying out the present invention. Furthermore, the components in the following embodiment include components that can be readily assumed by those skilled in the art, components that are essentially the same, and components within a so-called equivalent range. In addition, the components disclosed in the following embodiment can be suitably combined with one another.

[0028] Fig. Figure 1 is a cross-sectional view of a brake caliper according to one embodiment. As shown in Fig. As shown in Figure 1, a brake caliper 100 is a device that encloses a wheel (not shown) and a brake disc 101, which follows the wheel between two brake pads 102 and 103 to suppress rotational movement of the wheel. The brake caliper 100 comprises a brake disc 101, two brake pads 102 and 103, an electric actuator 104 that actuates the brake pad 102, and a housing 120.

[0029] The electric actuator 104 comprises a motor (not shown) that generates a rotary motion, a reduction gear 110 that decelerates the rotary motion, and a ball screw drive 1 that converts the rotary motion into a linear motion. In the following description, a direction parallel to an axis O1 of a spindle screw 2 of the ball screw drive 1 is referred to as the axial direction. In the axial direction, a direction in which the brake disc 101 is arranged as seen from the ball screw drive 1 is referred to as a first direction X1, and a direction opposite to the first direction X1 is referred to as a second direction X2.

[0030] The reduction gear 110 is a planetary gear mechanism. The reduction gear 110 comprises an input shaft 111, a sun gear 112, a ring gear 113, several planet gears 114, several transmission shafts 115 and a carrier 116.

[0031] The rotational motion of the motor is transmitted to the input shaft 111. The input shaft 111 extends in the axial direction. An axis O2 of the input shaft 111 lies on an extension line of the axis O1. The sun gear 112 passes through the input shaft 111 and is rotationally fixed to it. The ring gear 113 is an internal gear centered on the axis O2. An outer circumferential surface of the ring gear 113 is connected to the housing 120.

[0032] The planet gear 114 is arranged between the sun gear 112 and the ring gear 113 and meshes with both. The transmission shaft 115 passes through the planet gear 114. The planet gear 114 is rotatably mounted about the transmission shaft 115.

[0033] The support 116 is an annular component centered on axis O1. An outer circumferential surface of the support 116 is connected to a bearing 117. Therefore, the support 116 is rotatably mounted by the housing 120. A connecting section 10 of the spindle screw 2 is inserted into a central section of the support 116. The support 116 and the connecting section 10 are splined. Therefore, the support 116 and the connecting section 10 are coupled in such a way that they cannot rotate relative to each other. Furthermore, the transmission shaft 115 is positioned eccentrically to the radial outer surface of the central section of the support 116.

[0034] As described above, the sun gear 112 rotates around axis O2 when the rotary motion from the motor (not shown) is transmitted to the input shaft 111. The planetary gear 114 rotates around axis O2 while rotating around the transmission shaft 115. As a result, the carrier 116 and the spindle screw 2 rotate around axis O1. The rotational speed of the spindle screw 2 is reduced more than the rotational speed of the input shaft 111.

[0035] The ball screw drive 1 consists of the spindle screw 2, a nut 3, a ball 4 (in Fig. 1 not shown, see Fig. 4) and several deflectors 5 (in Fig. (1 is only one shown). The spindle screw 2 comprises the connecting section 10 connected to the support 116 and a spindle screw body 11, which is arranged in the first direction X1 with respect to the connecting section 10 and inserted into the nut 3. An outer circumferential surface of the spindle screw body 11 is provided with an outer circumferential running surface 13 extending in a helical direction and with several recesses 14 (in Fig. (1 is only one shown), which are radially recessed inwards.

[0036] The nut 3 is cylindrical with a base. Therefore, the nut 3 comprises a cylindrical nut body 6 and a cover 7 that closes an opening in the nut body 6. An inner circumferential raceway 6a, opposite the outer circumferential raceway 13, is provided on an inner circumferential surface of the nut body 6. A helical raceway 8 is formed between the outer circumferential raceway 13 and the inner circumferential raceway 6a. Several balls 4 are arranged in the raceway 8.

[0037] An outer circumferential surface 6b of the nut body 6 rests against a support surface 121 of the housing 120. Both the outer circumferential surface 6b and the support surface 121 of the nut body 6 are circular and centered on the axis O1. A tiny clearance is provided between the support surface 121 and the outer circumferential surface 6b of the nut body 6, allowing the nut 3 to slide. In other words, the support surface 121 supports the nut 3 so that it can slide axially. Furthermore, a rotation stop (not shown) is provided on the outer circumferential surface 6b of the nut body 6. The rotation stop prevents the nut 3 from rotating around the axis O1.

[0038] The cover 7 closes the opening of the nut body 6 in the first direction X1. A surface 7a of the cover 7 facing the first direction X1 is in contact with the brake pad 102.

[0039] When the nut 3 moves in the first direction X1 due to the rotation of the spindle screw 2, the brake pad 102 moves in the first direction X1. The brake pad 102 presses against the brake disc 101 in the first direction X1, and the brake disc 101 comes into contact with the brake pad 103. This clamps the brake disc 101 between the brake pads 102 and 103, restricting the rotation of the wheel (not shown).

[0040] The deflector 5 is a recirculating device that guides the ball 4, which has moved along one track in the raceway 8, back along one track. A deflector 5 is attached to a recess 14. In the present disclosure, a method for attaching the deflector 5 to the recess 14 is not particularly restricted. In other words, the deflector 5 may or may not be attached to the recess 14. Therefore, in the present disclosure, the deflector 5 can be loosely inserted into the recess 14. Alternatively, the deflector 5 can be provided with a fastening aid that fits into the recess 14. Alternatively, the deflector 5 can be bonded to the recess 14. Furthermore, the deflector 5 can be attached to the recess 14 by crimping. Whether the deflector 5 is attached as described above or not is not particularly restricted.

[0041] Viewed axially, the multiple deflectors 5 (multiple recesses 14) are arranged in different directions from the axis O1. This ensures that a load acting from the nut 3 via the ball 4 onto the spindle screw 2 is distributed evenly in the circumferential direction. It is even better if the multiple deflectors 5 are arranged at equal intervals in the circumferential direction.

[0042] Fig. Figure 2 is a perspective view of the deflector and the recess of the ball screw drive according to the embodiment. As in Fig. As shown in Figure 2, the deflector 5 comprises an S-shaped groove surface 21, a pair of deflector openings 32 and 32 that are open in the S-shaped groove surface 21, and a pair of tongues 40 and 40 that project towards the deflector openings 32. Details of the recess 14 and the deflector 5 are described below.

[0043] Fig. Figure 3 is an enlarged view of the recess and deflector according to the embodiment, seen from the radial outside. The following describes how in Fig. Figure 3 shows a direction orthogonal to axis O1 when viewed from the radial outside, designated as the cutting direction Y. Furthermore, a direction parallel to a virtual line Z extending along track 8 is designated as the spiral direction. As shown in Fig. As shown in Figure 3, the recess 14 has an inner circumferential surface 14b. The inner circumferential surface 14b has a pair of first opposite surfaces 15 and 15 and a pair of second opposite surfaces 16 and 16.

[0044] The first opposite surface 15 is a surface that extends in the cutting direction Y from the radial outside. The pair of first opposite surfaces 15 and 15 are axially opposite each other. The first opposite surface 15 extends linearly from the radial outside.

[0045] The second opposite surface 16 is a surface extending in the axial direction. The pair of second opposite surfaces 16 and 16 are opposite each other in the cutting direction Y. The pair of second opposite surfaces 16 is parallel to the axial direction (see axis O1). The length of the first opposite surface 15 from one end to the other in the cutting direction Y is longer than the length of the second opposite surface 16 from one end to the other in the axial direction.

[0046] The deflector 5 is point-symmetric with respect to a center point C (see Fig. 3) The deflector 5 has an outer circumferential surface 24, which forms a ring shape around the center point C. The outer circumferential surface 24 has a pair of first lateral surfaces 25 and 25, which face the pair of first opposite surfaces 15 and 15, and a pair of second lateral surfaces 26 and 26, which face the pair of second opposite surfaces 16 and 16.

[0047] An outer shape (outer circumferential surface 24) of the deflector 5 is identical to an inner shape (inner circumferential surface 14b) of the recess 14. Therefore, the first side surface 25 extends linearly in the cutting direction Y, similar to the first opposite surface 15. Similar to the second opposite surface 16, the second side surface 26 extends linearly in the axial direction. The length from one end to the other in the cutting direction Y of the first side surface 25 is longer than the length from one end to the other in the axial direction of the second side surface 26. The bottom surface 5a of the deflector 5 is in contact with the bottom surface 14a of the recess 14 (see Fig. 4). Floor area 5a and floor area 14a are flat surfaces.

[0048] As described above, the recess 14 and the deflector 5 are rectangular when viewed from the radial outside. Furthermore, the length of the recess 14 and the deflector 5 in the cutting direction Y is longer than its length in the axial direction.

[0049] To describe the shapes of the recess 14 and the deflector 5 in more detail, the first opposite surface 15 of the recess 14 is inclined with respect to the cutting direction Y and runs parallel to the spiral direction (see the virtual line Z). Likewise, the first side surface 25 of the deflector 5 is oriented parallel to the spiral direction. In other words, the first opposite surface 15 and the first side surface 25 are parallel to a screw thread 13a. Viewed from the radial outside, the recess 14 and the deflector 5 are parallelograms.

[0050] Furthermore, the screw thread 13a of the outer circumferential running surface 13 of the spindle screw 2 is cut out in a region that overlaps with the recess 14. For this purpose, a portion of the screw thread 13a is designed as a thin section 18 with a small thickness H. The thickness H is a thickness in an orthogonal direction to the helix direction.

[0051] If the first opposing surface 15 extends in the cutting direction Y, a section with a large thickness H and a section with a small thickness H are created in the thin section 18. The section with the small thickness H has relatively low strength, and the screw thread 13a is easily deformed. On the other hand, in the present embodiment, the first opposing surface 15 and the first side surface 25 are parallel to the screw thread 13a. In other words, the thickness H of the thin section 18 is uniform over the entire direction in which the thin section 18 extends. Therefore, in the thin section 18 of the present embodiment, there is no section with relatively low strength, and deformation of the screw thread 13a (thin section 18) is suppressed.Furthermore, the second opposite surface 16 and the second side surface 26 of the present embodiment are inclined with respect to the axial direction and run parallel to the orthogonal direction orthogonal to the spiral direction (see virtual line Z).

[0052] Next, the S-shaped groove surface 21 is described. A direction of extension in which the S-shaped groove surface 21 extends (direction along a virtual line W passing through the center of a groove width of the S-shaped groove surface 21 in Fig. The S-shaped groove surface 21, which runs in the S-shape (3), is referred to as an S-shaped direction. The S-shaped groove surface 21 is a circumferential groove surface whose interior forms a circumferential path. Therefore, when the ball 4 moves on the S-shaped groove surface 21, it returns along one track. Furthermore, the S-shaped groove surface 21 is S-shaped when viewed from its radial outer surface. In other words, the S-shaped groove surface 21 comprises a central groove surface 30, which is arranged along a central section of the S-shaped groove surface 21 in the S-shaped direction; two inlet / outlet groove surfaces 31, which are arranged along the S-shaped direction at both ends of the S-shaped groove surface 21; and a curved groove surface 33, which connects the central groove surface 30 and the inlet / outlet groove surfaces 31. Furthermore, the deflector opening 32, which is open in the inlet / outlet groove surface 31 in the cutting direction, is provided on the second side surface 26 of the deflector 5.

[0053] The central groove surface 30 and the inlet / outlet groove surface 31 are linearly shaped, and the balls 4 roll frictionlessly. Furthermore, the inlet / outlet groove surface 31 is connected to the outer circumferential running surface 13 of the spindle screw 2 via the deflection opening 32. The inlet / outlet groove surface 31 extends in a spiral direction and is parallel (linear) to the outer circumferential running surface 13. Therefore, the ball 4 enters the inlet / outlet groove surface 31 frictionlessly from the outer circumferential running surface 13. Since the inlet / outlet groove surface 31 extends in a spiral direction, it can be referred to as the spiral section.

[0054] The curved groove surface 33 (see virtual line W1 of the virtual line W in Fig. 3) is curved and arc-shaped when viewed from the radial direction. In other words, a central part of the groove width of the curved groove surface 33 deviates significantly from the spiral direction (see virtual line Z) as it approaches the central groove surface 30. Therefore, when the ball 4 rolls on the curved groove surface 33, it deviates from the spiral direction. Since the curved groove surface 33 is curved, it can be referred to as a curved region.

[0055] As described above, the length of the deflector 5 in the transverse direction Y is greater than its length in the axial direction. Therefore, the length of the central groove surface 30 in the cutting direction Y is also relatively long. Consequently, the S-shaped degree of curvature of the S-shaped groove surface 21 (curved groove surface 33) is S-shaped when viewed from the radial outside (see virtual line W1 in the virtual line W in Fig. 3) gently (small curvature). Accordingly, the ball 4 rolls gently on the S-shaped groove surface 21 (curved groove surface 33).

[0056] Furthermore, one groove shoulder 31a of the inlet / outlet groove surface 31 is largely cut out in the axial direction. This one groove shoulder 31a in the axial direction is oriented in the direction in which the center point C of the deflector 5 is located relative to the center (virtual line W) of the groove width of the inlet / outlet groove surface 31. Therefore, this one groove shoulder 31a is offset radially inward in the axial direction compared to the other groove shoulder 31b in the axial direction (see Fig. 8).

[0057] Fig. Figure 4 is a cross-sectional view that schematically shows a cross-section along the center of the S-shaped groove surface. A virtual line K1 in Fig. 4 is a line that extends the outer circumferential running surface 13 of the spindle screw 2 in the circumferential direction. Fig. Figure 4 shows only a part of the several spheres 4 to make the S-shaped groove surface 21 clearly visible.

[0058] As in Fig. As shown in Figure 4, the central groove surface 30 and the curved groove surface 33 are arranged radially inside the virtual line K1. The two curved groove surfaces 33 are inclined in the direction of the central section of the central groove surface 30 in the S-shaped direction, so that they are arranged gradually radially inwards. In other words, a cross-sectional shape obtained by cutting the central groove surface 30 and the curved groove surface 33 along the S-shaped direction is a concave shape. Therefore, the central groove surface 30 and the curved groove surface 33 are concave surfaces, and the balls 4, which roll on the central groove surface 30 and the curved groove surface 33, sink radially inwards.

[0059] To describe the movement of sphere 4 in detail, sphere 4 moves radially inwards when it approaches the central section of the central groove surface 30 from one of the two curved groove surfaces 33 in an S-shaped direction (see sphere 4A of the in Fig. 4 balls (4) are shown. The ball 4A moves radially outwards as it approaches the other curved groove surface 33 from the central part of the central groove surface 30 in an S-shaped direction. As a result, the ball 4 slides over a screw thread 6c of the inner circumferential running surface 6a. In the present embodiment, a motion R1 is a radial motion as the ball 4 rolls on the S-shaped groove surface 21 (the central groove surface 30 and the curved groove surface 33).

[0060] In the nut 3 of the present embodiment, height L1 is the height of the thread 6c of the inner circumferential running surface 6a. Height L2 is the height of the screw thread 13a of the outer circumferential running surface 13. The height L2 of the screw thread 13a of the outer circumferential running surface 13 is greater than the height L1 of the screw thread 6c (L2 > L1). Therefore, it is difficult for the ball 4 to run on the groove shoulder 13c of the outer circumferential running surface 13. The height is the distance (the depth) from the groove bottom to the groove shoulder.

[0061] As in Fig. As shown in Figure 4, the inlet / outlet groove surface 31 extends circumferentially from the deflector opening 32. In other words, the groove base of the inlet / outlet groove surface 31 is at a constant distance from the axis O1. In other words, unlike the concave surface (central groove surface 30 and curved groove surface 33), the inlet / outlet groove surface 31 of the present embodiment is not inclined such that it is positioned radially inward toward the central section in the S-shaped direction. Therefore, even when the ball 4 rolls on the inlet / outlet groove surfaces 31 and approaches the central section of the central groove surface 30 in the S-shaped direction (see ball 4B under the in Figure 4), it does not move radially inward. Fig. 4 balls shown 4). When a radially outward-directed load acts on the deflector 5, the ball 4B rolls on the inlet / outlet groove surface 31 and abuts the inner circumferential running surface 6a of the nut 3. Therefore, the radially outward movement of the deflector 5 is restricted, and the deflector 5 does not disengage from the recess 14.

[0062] In the present embodiment, the groove base of the inlet / outlet groove surface 31 is arranged radially inside the virtual line K1. Therefore, when a radially outward-directed load acts on the deflector 5, the deflector 5 moves slightly radially outward. The ball 4B, which rolls on the inlet / outlet groove surface 31, then also moves slightly radially outward and abuts the inner circumferential running surface 6a of the nut 3. Consequently, the radially outward movement of the deflector 5 is limited to a small amount of movement, and the deflector 5 does not disengage from the recess 14.

[0063] Fig. Figure 5 is a diagram, viewed from the recess, showing an opening (screw opening) in the outer circumferential running surface, which is provided on the second opposite surface of the recess. As in Fig. As shown in Figure 5, a spindle screw opening 13b of the outer circumferential running surface 13 is provided in the second opposite surface 16 of the inner circumferential surface 14b of the recess 14. The spindle screw opening 13b lies next to the deflection opening 32 in the rolling direction (S-shaped direction) of the ball 4 (see Figure 5). Fig. 2 to 4) of the deflector 5.

[0064] As in Fig. As shown in Figure 5, viewed in the rolling direction of the ball 4, the groove shape of the inlet / outlet groove surface 31 of the S-shaped groove surface 21 is larger than the groove shape of the outer circumferential running surface 13. In other words, viewed in the rolling direction of the ball 4, the groove shape of the deflector opening 32 is also larger than the groove shape of the spindle screw opening 13b. In other words, the spindle screw opening 13b is located within the deflector opening 32. Therefore, the deflector opening 32 is deeper than the spindle screw opening 13b and has a greater groove width.

[0065] For this reason, as in Fig. As shown in Figure 4, the inlet / outlet groove surface 31 is arranged radially within the virtual line K1 (outer circumferential running surface 13). Because the inlet / outlet groove surface 31 is arranged radially within the virtual line K1, the load exerted by the nut 3 on the inlet / outlet groove surface 31 via the ball 4 is reduced, and the deformation of the deflector 5 is suppressed.

[0066] Fig. 6 is a diagram showing a state in which the deflector is in a different position relative to the state in Fig. 5 has moved radially outwards. Since the groove shape of the deflector opening 32 is larger than the groove shape of the spindle screw opening 13b, the deflector opening 32 does not move inwards into the spindle screw opening 13b, even if the deflector 5 is moved radially outwards, as in Fig. 6 shown. In other words, it prevents the ball 4, which moves from the outer circumferential running surface 13 to the inlet / outlet groove surface 31, from being caught by an edge of the deflector opening 32.

[0067] Next, details of tongue 40 are described. As in Fig. As shown in Figure 2, the deflector 5 has an outer diameter surface 20 that projects radially outwards. The outer diameter surface 20 is located radially outside the groove shoulder 13c of the outer circumferential running surface 13. The tongue 40 comprises a base 41 with a semicircular column shape that projects radially outwards from the outer diameter surface 20, and a tongue body 42 that projects from the base 41 towards the deflector opening 32. Furthermore, two tongues 40 are axially spaced apart. The screw thread 6c of the nut 3 is located between the two tongues 40.

[0068] As in Fig. As shown in Figure 3, the tongue 40 extends in a spiral direction. Although not specifically shown, the tongue 40 is located within the inner circumferential running surface 6a of the nut 3. Furthermore, the tongue 40 is separated from the inner circumferential running surface 6a of the nut 3 and is not in contact with it.

[0069] A central section of the tongue body 42 in the lateral direction (orthogonal direction) overlaps the virtual line Z. A length H2 of the tongue body 42 in the lateral direction (orthogonal direction) decreases towards the deflector opening 32 and has a conical shape. A tip 43 of the tongue body 42 is arranged radially outside the inlet / outlet groove surface 31 (more precisely, radially outside a section of the inlet / outlet groove surface 31 that is closer to the curved groove surface 33). The central part of the tongue body 42 in the spiral direction is arranged radially outside the curved groove surface 33. Furthermore, the base 44 of the tongue body 42 is arranged radially outside the central groove surface 30 (in particular, radially outside a section of the central groove surface 30 that is closer to the curved groove surface 33).

[0070] As in Fig. As shown in Figure 4, the tip 43 of the tongue body 42 is arranged radially outside the groove shoulder 6e of the inner circumferential running surface 6a. Therefore, the step L3 between the groove bottom of the inner circumferential running surface 6a and the tip 43 is small. Furthermore, the tongue body 42 has a radially inwardly directed inner diameter surface 45. The inner diameter surface 45 is inclined such that it is arranged radially inward from the tip 43 toward the base 44.

[0071] According to the tongue 40 described above, the ball 4, which enters the S-shaped groove surface 21 from the deflector opening 32, comes into contact with the tip 43 of the tongue body 42 on the inlet / outlet groove surface 31. As a result, the ball 4, which has moved in a spiral direction, changes its direction towards a radially inner side (see arrow A1 in Figure 1). Fig. 4) The ball 4 then moves radially inwards away from the tongue body 42. Therefore, the ball 4 moves radially inwards compared to the case where the tongue 40 is not present. Since the step L3 of the tip 43 is small, the ball 4 moves smoothly without getting stuck upon contact with the tip 43.

[0072] The ball 4, which moves radially inwards into the tongue body 42, is guided by the inner diameter surface 45 and gradually positioned on the radially inner side. Therefore, the ball 4 moves along the concave surface (the central groove surface 30 and the curved groove surface 33). This reliably prevents contact between the ball 4 and the thread 6c of the inner circumferential running surface 6a.

[0073] The effects of the ball screw drive 1 according to the embodiment are described below. The effects of the ball screw drive 1 comprise a first effect, a second effect, and a third effect. The second and third effects are described using comparative examples.

[0074] The first effect occurs when the ball 4 changes its path on the S-shaped groove surface 21. As an example, the present description describes a case in which the ball 4 changes its path from the groove surface 21. Fig. 3 spindle screw opening 13b arranged on the lower left enters the deflector opening 32.

[0075] Fig. Figure 7 is an enlarged view showing part of the depression and deflector in the lower left. Fig. 3 is enlarged. Fig. Figure 8 is a cross-sectional view along line VIII-VIII in Fig. 7. As in Fig. As shown in Figure 7, the ball 4, which has entered the S-shaped groove surface 21 from the deflector opening 32, moves in a spiral direction (virtual line Z) along the inlet / outlet groove surface 31. Then the ball 4 begins to rotate from the virtual line Z on the curved groove surface 33 in the second direction X2 (see W1 in the virtual line W in Figure 7). Fig. 7) Then the ball 4 moves on the central groove surface 30 in a direction that is inclined by 01° to the second direction X2 with respect to the spiral direction.

[0076] As described above, when rolling on the curved groove surface 33 and the central groove surface 30, the ball 4 receives a pressure load in the second direction X2 (see arrow A3 in Fig. 7) A part of the S-shaped groove surface 21, which pushes the ball 4 in the second direction X2, is a one-sided groove surface (hereinafter referred to as the “guide surface 28”) which is arranged in the first direction X1 with respect to the virtual line W.

[0077] At both ends of the curved groove surface 33 and the central groove surface 30 in the S-shaped direction, the magnitude of the depression in the radially inward direction is small (see Fig. 4) If the tongue 40 is not present, as in the case of the Fig. In Figure 8, the sphere 4D shown is located within the inner circumferential running surface 6a of the nut 3 and bears against this surface. A portion of the inner circumferential running surface 6a that is in contact with the sphere 4D is a one-sided grooved surface (hereinafter referred to as the counter surface 6d) that is oriented in the second direction X2 with respect to the central part of the groove width of the inner circumferential running surface 6a.

[0078] Therefore, it is likely that the ball 4D will be jammed between a portion of the guide surface 28 near the groove shoulder 31b of the S-shaped groove surface 21 (hereinafter referred to as the "guide contact section 29") and a portion of the counter surface 6d (counter contact section 6f) near the groove shoulder 6e. In other words, there is a high probability that the rolling of the ball 4 will be impeded or that the groove shoulder 31b or the groove shoulder 6e will be damaged.

[0079] On the other hand, according to the present embodiment, the sphere 4E is similar to the one in Fig. The ball 4E, shown in Figure 8, is in contact with the tip 43 of the tongue body 42, and the ball 4E moves radially inwards. Therefore, the ball 4E does not collide with the counter surface 6d (counter-contact section 6f), and it is prevented that the ball 4E is clamped between the guide contact section 29 and the counter-contact section 6f. As described above, according to the embodiment, the first effect is shown to ensure smooth rolling of the ball 4 and also to prevent breakage of the groove shoulder 31b.

[0080] The second effect is related to the fact that the deflector 5 is mounted on the spindle screw 2. Therefore, in comparative example 1, the deflector 5 is located in the nut 3.

[0081] Fig. Figure 9 is a cross-sectional view along a central section of a groove width of an S-shaped groove surface of a ball screw drive according to comparative example 1. As in Fig. Figure 9 shows a ball screw drive 1001 of comparative example 1 comprising a spindle screw 1002 and a nut 1003. The ball screw drive 1001 differs from the embodiment in that a deflector 1005 is provided on the nut 1003.

[0082] Furthermore, the height L11 of a screw thread 1006c of an inner circumferential running surface 1006a of the nut 1003 is equal to L1 in the embodiment. A height L12 of a screw thread 1013a of an outer circumferential running surface 1013 of the spindle screw 1002 is the same as L2 in the embodiment. A virtual line K2 in Fig. 9 is a line that extends the inner circumferential running surface 1006a in the circumferential direction.

[0083] When a ball 1004 moves on an S-shaped groove surface 1021 of the deflector 1005, the amount of movement R2 is a radial amount of movement of the ball 1004. The amount of movement R2 in the radial direction is the amount of movement for the ball 1004 to exceed the height L12 of the screw thread 1013a of the outer circumferential running surface 1013 in order to avoid contact with the screw thread 1013a. In the inner circumferential running surface 1006a of Comparative Example 1, the screw thread 1006c has a height L11, which is small. Therefore, the bottom of the inner circumferential running surface 1006a is flat, and the step between the bottom of the inner circumferential running surface 1006a and the deepest section of the S-shaped groove surface 1021 is large. In other words, according to comparison example 1, the amount of motion R2 by which the ball 1004 moves in the radial direction is large.

[0084] On the other hand, as in Fig. As shown in Figure 4, the height L2 of the screw thread 13a is large on the outer circumferential running surface 13 according to the embodiment. Therefore, the bottom of the outer circumferential running surface 13 is deep, and the step between the bottom of the outer circumferential running surface 13 and the deepest section of the S-shaped groove surface 21 is small. In other words, the amount of movement R1 by which the ball 4 moves in the radial direction is smaller than the amount of movement R2 of Comparative Example 1.

[0085] As described above, the step size (radial movement) of the S-shaped groove surface 1021 of Comparative Example 1 is large. On the other hand, the step size of the S-shaped groove surface 21 of the embodiment is small. Therefore, the inclination of the S-shaped groove surface 21 in the depth direction (radial direction) is gentle, and flatness is ensured. In other words, the embodiment exhibits the second effect, namely that the ball 4, which rolls on the S-shaped groove surface 21, moves uniformly.

[0086] The third effect is related to the fact that the length of the deflector 5 (recess 14) in the transverse direction Y is greater than its axial length. Therefore, in comparative example 2, a circular deflector is provided which is the same length in the cutting direction Y and in the axial direction.

[0087] Fig. Figure 10 is a diagram that abstractly represents a deflector according to the comparative example 2. Fig. Figure 11 is a diagram that illustrates the deflector according to the embodiment in an abstract manner. As in Fig. As shown in Figure 10, the deflector 2005 of comparison example 2 has a circular outer shape. According to the deflector 2005 of comparison example 2, the angle θ11, at which the ball rotates along an S-shaped groove surface 2021 in the axial direction, is relatively large. Furthermore, according to the deflector 2005 of comparison example 2, the angle θ12, at which the ball rotates along the S-shaped groove surface 2021 in the radial direction, is relatively large.

[0088] As in Fig. As shown in Figure 11, the deflector 5 is longer in the cutting direction than in the axial direction according to the embodiment. Therefore, the angle θ13 in which the ball rotates along the S-shaped groove surface 21 in the axial direction is small, and the inclination is gentler than in Comparative Example 2. Furthermore, the angle θ14 in which the ball rotates along the S-shaped groove surface 21 in the radial direction is also small, and the inclination is gentler than that of Comparative Example 2. Therefore, according to the embodiment, the third effect is shown, and the ball 4 rolls more smoothly on the S-shaped groove surface 21.

[0089] At the in Fig. In contrast to the deflector 2005 shown in Comparative Example 2, it is also necessary to rotate the deflector after mounting it in the recess to ensure that the S-shaped groove surface 21 and an outer circumferential running surface (not shown) are continuous. On the other hand, according to the embodiment, the recess 14 and the deflector 5 are parallelograms (quadrilaterals) when viewed from the radial outside. In other words, the recess 14 and the deflector 5 are not circular. Therefore, the S-shaped groove surface 21 and the outer circumferential running surface 13 only become continuous once the deflector 5 is inserted into the recess 14. Consequently, it is not necessary to adjust the orientation of the deflector 5 by rotating it after it has been mounted in the recess 14.

[0090] As described above, the ball screw drive 1, according to the embodiment, comprises the nut 3, which is provided with the inner circumferential raceway 6a on its inner circumferential surface; the spindle screw 2 inserted into the nut 3, which is provided with the outer circumferential raceway 13 on its outer circumferential surface; the multiple balls 4, which are arranged on the raceway 8 between the outer circumferential raceway 13 and the inner circumferential raceway 6a; and at least one deflector 5, which allows the balls 4 to circulate. At least one recess 14 is provided on the outer circumferential surface of the spindle screw 2, which is radially recessed inwards and receives the deflector 5. Two spindle screw openings 13b of the outer circumferential raceway 13 are provided on the inner circumferential surface 14b of the recess 14, opening towards the deflector 5.The deflector 5 comprises a pair of deflector openings 32 and 32, which open in the outer circumferential surface 24 of the deflector 5 and are connected to the spindle screw openings 13b, the circumferential groove surface (S-shaped groove surface 21), which is connected to each of the two deflector openings 32 and 32 and has an interior that forms a circumferential path, and a pair of tongues 40 and 40, which are arranged radially outside the circumferential groove surface (S-shaped groove surface 21) and project towards the deflector openings 32. The tip 43 of the tongue 40 is radially outside a virtual spiral E (see . Fig. 4) arranged, connecting the centers of the several balls 4 rolling in the track 8.

[0091] In the ball screw drive 1 described above, the ball 4 is prevented from being jammed between the circumferential groove surface (S-shaped groove surface 21) and the inner circumferential running surface 6a. Therefore, smooth rolling of the ball 4 and the prevention of breakage of the deflection 5 can be achieved.

[0092] Furthermore, according to this embodiment, the tongue 40 has a radially inwardly directed inner diameter surface 45. The inner diameter surface 45 is inclined such that it is gradually positioned radially inward away from the tip 43.

[0093] Accordingly, ball 4 moves uniformly radially inwards.

[0094] According to this embodiment, the tip 43 is arranged on the inner circumferential surface 6a of the nut 3.

[0095] In this arrangement, as the ball 4 moves radially inwards from the inlet / outlet groove surface 31 into the tongue body 42, it rolls gently away without being caught by the tip 43.

[0096] The circumferential groove surface according to the embodiment is the S-shaped groove surface 21, which is formed in an S-shape. The S-shaped groove surface 21 has the helical region, which is arranged near the deflector opening 32 and extends along the helical direction in which the raceway 8 extends, and a curved region that adjoins the helical region and gradually deviates from the helical direction. The tip 43 is arranged radially outwards with respect to the helical region.

[0097] According to the embodiment, the circumferential groove surface is the S-shaped groove surface 21. Viewed from the radial outside of the spindle screw 2, the length of the recess 14 and the deflector 5 in the cutting direction Y crossing the axial direction is greater than the length in the axial direction parallel to the spindle screw 2.

[0098] According to this shape, the ratio of the S-shaped groove surface 21 in the cutting direction Y increases, and the movement of the ball 4 on the S-shaped groove surface 21 becomes uniform.

[0099] Furthermore, according to the embodiment, the height L2 of the screw thread 13a on the outer circumferential running surface 13 is greater than the height L1 of the screw thread 6c on the inner circumferential running surface 6a.

[0100] Accordingly, it is difficult for the ball 4 to run on the groove shoulder 13c of the outer circumferential running surface 13. Furthermore, the inclination of the S-shaped groove surface 21 in the radial direction is gentle, and the movement of the ball 4 on the S-shaped groove surface 21 becomes frictionless.

[0101] Furthermore, according to the embodiment, the circumferential groove surface (S-shaped groove surface 21) has a pair of inlet / outlet groove surfaces 31 and 31, which are arranged at both ends in the extension direction of the circumferential groove surface (S-shaped groove surface 21) and extend in the circumferential direction from the deflector opening 32, and a concave surface (central groove surface 30 and curved groove surface 33), where the ball 4 sinks radially inwards, which is arranged between the pair of inlet / outlet groove surfaces 31 and 31.

[0102] According to this embodiment, the ball 4 rolling on the inlet / outlet groove surface 31 comes into contact with the inner circumferential running surface 6a even when a radially outward-directed load acts on the deflector 5. Therefore, the radially outward movement of the deflector 5 is limited, and the deflector 5 does not disengage from the recess 14.

[0103] Furthermore, according to the embodiment, the deflection opening 32 of the S-shaped groove surface 21 is provided on the outer circumferential surface 24 of the deflector 5. The spindle screw opening 13b of the outer circumferential running surface 13 is provided on the inner circumferential surface 14b of the recess 14 and extends to the deflection opening 32. The groove shape of the deflection opening 32 is larger than the groove shape of the spindle screw opening 13b.

[0104] Even when the deflector 5 moves radially outwards, the edge of the deflector opening 32 does not penetrate the interior of the spindle screw opening 13b. Therefore, the edge of the deflector opening 32 does not touch the ball 4.

[0105] Although the ball screw drive according to the embodiment described above, the present disclosure is not limited to the ball screw drive shown in the embodiment. For example, the ball screw drive of the present disclosure can be applied to a device other than the electric actuator 104 and the brake caliper 100.

[0106] Furthermore, in this embodiment, the inner circumferential surface 14b of the recess 14 and the outer circumferential surface 24 of the deflector 5 are parallelograms, but the present disclosure may have a shape other than a parallelogram. Accordingly, in the present disclosure, the inner circumferential surface 14b of the recess 14 and the outer circumferential surface 24 of the deflector 5 may, for example, have a quadrilateral or an elliptical shape. The pair of first opposing surfaces 15 and 15 and the pair of first side surfaces 25 and 25 extend in the spiral direction, but may also extend in the cutting direction Y. The second opposing surface 16 and the second side surface 26 extend in the direction orthogonal to the spiral direction (see virtual line Z), but may also extend in the axial direction.If the recess 14 and the deflector 5 have a quadrilateral shape, a rectangle, a square, a parallelogram, a rhombus, and a trapezoid are included. Furthermore, one corner of the quadrilateral shape may be curved and is not particularly restricted.

[0107] Furthermore, the S-shaped groove surface 21 is shown by way of example as a circumferential groove surface of the embodiment, but the present disclosure is not limited to this shape. Fig. Figure 12 is a schematic view of a deflector according to modification 1 as seen from the radial outside. Within the scope of the present disclosure, as in the case of the Fig. In the deflector 205 of modification 1 shown in Figure 12, a circumferential groove surface 221 extends in a reverse spiral direction Z1 opposite to the spiral direction Z. According to modification 1, an inlet / outlet groove surface 231 of the circumferential groove surface 221 also extends in the reverse spiral direction Z1.

[0108] In the S-shaped groove surface 21 of the embodiment, the central groove surface 30 and the inlet / outlet groove surface 31 are straight, but a curved section may be partially provided. Furthermore, according to the exemplary embodiment, the central section of the groove width of the deflector opening 32 (see virtual line W in Fig. 3) and the central portion of the groove width of the outer circumferential running surface 13 is arranged such that they coincide in the spiral direction. However, in the present disclosure, the central portion of the groove width of the deflector opening 32 and the central portion of the groove width of the outer circumferential running surface 13 cannot coincide in the spiral direction (they may diverge in the axial direction). Moreover, although the inlet / outlet groove surface 31 of the embodiment extends in the spiral direction, the inlet / outlet groove surface of the present disclosure cannot extend in the spiral direction. In other words, the inlet / outlet groove surface can extend in the cutting direction Y or in the reverse spiral direction Z1 (see inlet / outlet groove surface 231 in Fig. 12).

[0109] Furthermore, the S-shaped groove surface (circulating groove surface) 21 of the embodiment has the inlet / outlet groove surface 31, the distance of which from the axis O1 is constant, but the circumferential groove surface of the present disclosure cannot have the inlet / outlet groove surface 31. Fig. Figure 13 is a schematic cross-sectional view of a deflector according to modification 2, taken along a circumferential groove surface. In the present disclosure, a circumferential groove surface 321, as in the one described in Fig. The deflector 305 shown in Figure 13 according to modification 2 has only a concave surface in which the ball 4 sinks radially inwards.

[0110] Note that the concave surface in the present disclosure is a concave surface 321A (see virtual line in Fig. 13) includes the surface which is flat (linear) in the axial direction, in addition to the concave surface which is recessed in the direction of axis O1, as shown in modification 2. The concave surface 321A, which has a planar shape, is also arranged radially within the virtual line K1 (extension line of the outer circumferential running surface 13). In other words, the ball 4 can be threaded via the thread 6c (see Fig. 4) the mother 3 slide. The in Fig. The virtual line K321 shown in Figure 13 is a trajectory of the center of the sphere 4, which rolls on the outer circumferential running surface 13 and the circumferential groove surface 321. The Fig. The virtual line K321A shown in Figure 13 is a trajectory of the center of the sphere 4, which rolls on the outer circumferential running surface 13 and the concave surface 321A. A Fig. The virtual line K8 shown in Figure 13 is a line resulting from the extension of the trajectory of the center of the sphere 4 as it rolls on the outer circumferential running surface 13 (track 8). As shown in Figure 13, the virtual line K8 is a line resulting from the extension of the trajectory of the center of the sphere 4 as it rolls on the outer circumferential running surface 13 (track 8). Fig. As shown in Figure 13, the angle of curvature θ321A at the entry into the concave surface 321A from the outer circumferential running surface 13 is smaller than the angle of curvature θ0321 at the entry into the circumferential groove surface 321 from the outer circumferential running surface 13. Therefore, the ball 4 can roll (enter) the concave surface 321A without friction.

[0111] Furthermore, in the present disclosure, the height L1 of the screw thread 6c of the inner circumferential running surface 6a can be equal to or greater than the height L2 of the screw thread 13a of the outer circumferential running surface 13. In addition, the deflector 5 of the exemplary embodiment is longer in the cutting direction Y than in the axial direction. However, the deflector 5 of the present disclosure can be longer in the axial direction.

[0112] Furthermore, the material and manufacturing process for the deflector are not particularly restricted in the present disclosure. For example, the deflector can be made from a resin material such as nylon 66 resin. In addition, the deflector can be manufactured by a metal powder injection molding process. Moreover, the deflector of the present embodiment consists of a single component, but can also be formed from two or more components. If the deflector consists of two or more components, its division plane is not particularly limited. The deflector can be divided into two parts on the inner circumferential side and the outer circumferential side, or in the first direction X1 and the second direction X2.

[0113] Regarding the radial position of the tip 43 of the tongue 40, in the present embodiment the tip 43 is arranged on the inner circumferential surface 6a of the nut 3, but the present disclosure is not limited to this, as long as the ball 4 can be guided radially inwards. In other words, it is sufficient if the tip 43 is radially outside the virtual spiral E (see Fig. 4) is arranged, connecting the centers D of the balls 4 rolling on the track 8. If the tip 43 is arranged radially outside the virtual spiral E, the tip 43 touches the ball 4 at a position radially outside the center D. This is because the path of the ball 4 can be changed radially inwards.

[0114] Furthermore, the two tongues 40 are separated from each other in the present revelation, but a distance Q (see Fig. 12) The gap between the tongue bodies 42 can be smaller than the diameter of the ball 4. This prevents the ball 4 from falling (being trapped) in a gap between the tongue bodies 42. In other words, the ball 4 moves smoothly from the inner diameter surface 45 of one tongue body 42 to the inner diameter surface 45 of the other tongue body 42.

[0115] Regarding the position of the tip 43 of the tongue body 42, in the present embodiment the tip 43 is arranged radially outside the spiral region (inlet / outlet groove surface 31), but the present disclosure is not limited thereto. The position in which the ball 4 is trapped in the S-shaped groove surface 21 is not constant. Therefore, the tip 43 of the present disclosure may be arranged closer to the deflector opening 32 than at a predetermined position where the ball 4 is trapped in the S-shaped groove surface 21. In other words, the present disclosure is not particularly limited, and the tip 43 of the tongue 40 may be arranged radially outside with respect to the curved region (curved groove surface 33) or at the end of the central groove surface 30 in the S-shaped direction. Modifications are described below.

[0116] Fig. Figure 14 is a schematic cross-sectional view of a deflector according to modification 3 along a circumferential groove surface. A deflector 405 according to modification 3 comprises a pair of tongues 440. A tip 443 of a tongue body 442 of the tongue 440 is in contact with a virtual line N1. The virtual line N1 is a straight line passing through the axis O1 of the spindle screw 2 and a groove bottom 432N of a deflector opening 432. According to this tongue 440, the ball 4, which has entered the deflector opening 432, is immediately guided radially inwards. Therefore, the possibility of the ball 4 being trapped is extremely low. Furthermore, when the tip 443 crosses the virtual line N1, the ball 4 is prevented from contacting the inner circumferential surface 6a, and the load-bearing capacity of the ball screw drive decreases. Therefore, according to modification 3, there is no possibility of the load-bearing capacity of the ball screw drive becoming small.As described above, in the present disclosure it is desirable that the tip 443 does not cross the virtual line N1.

[0117] Fig. Figure 15 is a schematic cross-sectional view of a deflector according to modification 4 along a circumferential groove surface. A deflector 505 according to modification 4 comprises a pair of tongues 540. A tip 543 of a tongue body 542 of the tongue 540 is in contact with a virtual line N2. The virtual line N2 extends linearly along a second side surface 526 of the deflector 505. Also in the tongue 540 according to modification 4, the tip 543 is positioned closer to the deflector opening 532 than in the embodiment. Therefore, the possibility of the ball 4 becoming jammed is low.

[0118] Fig. Figure 16 is a schematic view of a deflector according to modification 5, seen from the radial outside. As in Fig. As shown in Figure 16, a deflector 605 of modification 5 comprises a pair of tongues 640 (only one is shown). Viewed from the radial outside, the deflector 605 has a circumferential (spiral) length N3 from the axis O1 to a second side surface 626. One in Fig. The virtual line N4 shown in Figure 16 extends linearly in the axial direction and is located at a position where its distance from the axis O1 in the circumferential (spiral) direction is half that of N3. In modification 5, a tip 643 of a tongue body 642 is in contact with the virtual line N3 when viewed from the radial outside. Therefore, the tip 643 of modification 5 is further from the deflector opening 632 than the tip 443 of modification 3 and the tip 543 of modification 4, and the present disclosure may have a tongue similar to the tongue 640.

[0119] Although modifications 3 to 5 have been described above, in the present disclosure the tip of the tongue can be located between the virtual line N1 (see Fig. 14) and the virtual line N2 (see Fig. 15) or between the virtual line N2 (see Fig. 15) and the virtual line N4 (see Fig. 16) be arranged. The tongue mentioned above also ensures smooth rolling of the ball and prevents breakage of the groove shoulder of the circumferential groove surface.

[0120] Furthermore, according to the embodiment, the tongue pair 40 and 40 is arranged such that they are spaced apart from each other in the axial direction (see Fig. 2, Fig. 3, etc.). In other words, a space is provided between the pair of tongues 40 and 40, but the pair of tongues 40 and 40 may be joined together in the present revelation. Fig. Figure 17 is a schematic view of a deflector according to modification 6, viewed from the radial outside. More precisely, as in Fig. As shown in Figure 17, the present disclosure may include a deflector 705 with a wall 750 connecting a pair of tongues 740 and 740. According to the deflector 705 of modification 6, the ball 4 is prevented from falling out (moving radially outward) between the pair of tongues 740 and 740. This prevents the ball 4 from coming into contact with the groove shoulder 6e (see Figure 17). Fig. 8) comes into contact with the mother 3.

[0121] As in Fig.As shown in Figure 17, in the present disclosure, an inner circumferential side surface 733a, located on the inner circumferential side, can have an arc shape (R-shape) when viewed from the radial outside in a curved groove surface 733 (curved region W1) of the S-shaped groove surface 721. Accordingly, it is less likely that the ball 4 will be engaged by the inner circumferential side surface 733a, and frictionless rolling of the ball 4 is ensured.

[0122] It should be noted that the present disclosure may be a combination of the following configurations. (1) A ball screw drive comprises: a nut which has an inner circumferential running surface on an inner circumferential surface, a spindle screw which is inserted into the nut and has an outer circumferential running surface on an outer circumferential surface, several balls arranged on a raceway between the outer circumferential running surface and the inner circumferential running surface, and at least one deflector that allows the multiple balls to circulate. The outer circumferential surface of the spindle screw is provided with at least one recess that is radially recessed inwards and accommodates the deflector. The recess has an inner circumferential surface which is provided with two spindle screw openings in the outer circumferential running surface, and the two spindle screw openings are open in the direction of the deflector. The deflector includes: a pair of deflection openings that open in an outer circumferential surface of the deflector and are connected to the two spindle screw openings, a circumferential groove surface connected to each of the two deflection openings and having an interior that forms a circumferential path, and a pair of tongues arranged radially outside the circumferential groove surface and projecting towards the pair of deflection openings. Each pair of tongues has a tip that is arranged radially outside a virtual spiral connecting the centers of the several balls rolling on the track. (2) The ball screw drive according to (1), in which the tongue has a radially inward directed inner diameter surface and the inner diameter surface is inclined in such a way that it is gradually sunken radially inwards with increasing distance from the tip. (3) The ball screw drive according to (1) or (2), in which the tip is located on the inner circumferential running surface of the nut. (4) The ball screw drive according to one of points (1) to (3), at which The circumferential groove surface is an S-shaped groove surface that is formed in an S-shape. The S-shaped grooved surface comprises: a spiral-shaped area located near the deflector opening and extending along a spiral direction in which the raceway extends, and a curved area that borders the spiral area and gradually deviates from the spiral direction. The tip is positioned radially outwards in relation to the spiral area. (5) The ball screw drive according to any of points (1) to (3), wherein the circumferential groove surface is an S-shaped groove surface formed in an S-shape. The S-shaped groove surface comprises: a spiral-shaped area located near the deflector opening and extending along a spiral direction in which the raceway extends, and a curved area that borders the spiral area and gradually deviates from the spiral direction. The tip is positioned radially outside the curved area. (6) The ball screw drive according to one of points (1) to (5), at which The circumferential groove surface is an S-shaped groove surface that is formed in an S-shape. Viewed from the radial outside of the spindle screw, the recess and the deflector have a length in a cutting direction that intersects an axial direction that is greater than a length in the axial direction parallel to the spindle screw. (7) The ball screw drive according to one of points (1) to (3), at which the circumferential groove surface extends in a reverse spiral direction, which is opposite to the spiral direction in which the raceway extends. (8) The ball screw drive according to one of points (1) to (7), at which The outer circumferential running surface has a thread height that is greater than the thread height of the inner circumferential running surface. (9) The ball screw drive according to one of points (1) to (8), at which the circumferential groove area comprises: a pair of inlet / outlet groove surfaces arranged at both ends in a direction of extension of the circumferential groove surface and extending in a circumferential direction from the deflector openings, and A concave surface in which the multiple spheres sink radially inwards. The concave surface is located between the pair of inlet / outlet groove surfaces. (10) The ball screw drive according to one of points (1) to (8), at which the circumferential groove surface has a concave surface in which the multiple spheres sink radially inwards, and The concave surface is linear when viewed in the axial direction. (11) The ball screw drive according to one of points (1) to (10), at which The deflection opening has a groove shape that is larger than the groove shape of the spindle screw. Reference symbol list 1, 1001 BALL WINDING DRIVE 2, 1002 SPINDLE SCREW 3, 1003 MOTHER 4, 1004 BALLS 5, 205, 305, 405, 505, 605, 705, 1005, 2005 DIVERTER 6 BODY 6a, 1006a INNER CIRCUMFERENTIAL RUNNING AREA 6c, 1006c SCREW THREAD 6e Grooved Shoulder 6f COUNTER-CONTACT SECTION 8 CAREER 11 spindle screw bodies 13 Outer Circumferential Running Surface 13a SCREW THREAD 13b Spindle Screw Opening 13c Grooved Shoulder 14. IN-DEPTH STUDY 15 FIRST OPPOSITE SURFACES 16 SECOND OPPOSITE SURFACES 18 THIN PART 20 OUTER DIAMETER AREA 21, 1021, 2021 S-shaped groove surface (circumferential groove surface) 25 FIRST SIDE 26 SECOND SIDE 29 MANAGEMENT CONTACT SECTION 30 CENTRAL GROOVED SURFACE 31 Inlet / Outlet Groove Surface 32 Diverter Opening 33 Curved Grooved Surface 40 Tongue 100 brake calipers 104 ELECTRIC ACTUATOR 120 HOUSINGS QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP 2004-225770 A

[0004]

Claims

[1] A ball screw drive comprising: a nut which has an inner running surface on an inner circumferential surface; a spindle screw which is inserted into the nut and has an outer circumferential running surface on an outer circumferential surface; several balls arranged on a raceway between the outer circumferential running surface and the inner circumferential running surface; and at least one deflector that allows the multiple balls to circulate, wherein the outer circumferential surface of the spindle screw is provided with at least one recess that is radially recessed inwards and accommodates the deflector, the recess has an inner circumferential surface which is provided with two spindle screw openings in the outer circumferential running surface, wherein the two spindle screw openings are open towards the deflector, The deflector includes: a pair of deflection openings that open in an outer circumferential surface of the deflector and are connected to the two spindle screw openings, a circumferential groove surface connected to each of the two deflection openings and having an interior that forms a circumferential path, and a pair of tongues arranged radially outside the circumferential groove surface and projecting towards the pair of deflection openings, and wherein each pair of tongues has a tip that is arranged radially outside a virtual spiral connecting the centers of the multiple balls rolling on the track. [2] The ball screw drive according to claim 1, wherein each pair of tongues has a radially inwardly directed inner diameter surface, and the inner diameter surface is inclined in such a way that it gradually shifts radially inwards with increasing distance from the tip. [3] The ball screw drive according to claim 1 or 2, wherein the tip is arranged on the inner circumferential running surface of the nut. [4] The ball screw drive according to one of claims 1 to 3, wherein the circumferential groove surface is an S-shaped groove surface that is formed in an S-shape, the S-shaped grooved surface includes: a spiral area located near each of the pair of deflection openings and extending along a spiral direction in which the raceway extends, and a curved area adjacent to the spiral area and gradually deviating from the spiral direction, and the tip is located radially outside the spiral area. [5] The ball screw drive according to one of claims 1 to 3, wherein the circumferential groove surface is an S-shaped groove surface that is formed in an S-shape, the S-shaped grooved surface includes: a spiral-shaped area located near each of the pair of deflection openings and extending along a spiral direction in which the raceway extends, and a curved area adjacent to the spiral area and gradually deviating from the spiral direction, and The tip is located radially outside the curved area. [6] The ball screw drive according to any one of claims 1 to 5, wherein the circumferential groove surface is an S-shaped groove surface, which is formed in an S-shape, and Viewed from the radial outside of the spindle screw, the recess and the deflector in a cutting direction that crosses an axial direction have a length that is greater than a length in the axial direction parallel to the spindle screw. [7] The ball screw drive according to one of claims 1 to 3, wherein the circumferential groove surface extends in a reverse spiral direction which is opposite to a spiral direction in which the raceway extends. [8] The ball screw drive according to any one of claims 1 to 7, wherein the outer circumferential running surface has a thread height that is greater than a thread height of the inner circumferential running surface. [9] The ball screw drive according to any one of claims 1 to 8, wherein the circumferential groove surface comprises: a pair of inlet / outlet groove surfaces arranged at both ends in a direction of extension of the circumferential groove surface, wherein the pair of inlet / outlet groove surfaces extends in a circumferential direction from the pair of deflector openings, and a concave surface in which the multiple spheres sink radially inwards, the concave surface being arranged between the pair of inlet / outlet groove surfaces. [10] The ball screw drive according to any one of claims 1 to 8, wherein the circumferential groove surface has a concave surface in which the multiple spheres sink radially inwards, and The concave surface is linear when viewed in the axial direction. [11] The ball screw drive according to any one of claims 1 to 10, wherein the pair of deflection openings has a groove shape that is larger than the groove shape of the two spindle screw openings.

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