JP2016061350A - Roller cam mechanism, rotation transmission device and steer-by-wire type steering device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motion conversion mechanism which can place a large axial load on a clearance between a first disc and a second disc, and can easily position the first disc and the second disc in parallel with each other.SOLUTION: A roller cam mechanism has a first disc 2 and a second disc 3, and a plurality of rollers 4 which are arranged between an axial rear face 2b of the first disc 2 and an axial front face 3a of the second disc 3. A first cam face 6 is arranged at the axial rear face 2b of the first disc 2, a second cam face 7 is arranged at the axial front face 3a of the second disc 3, and the rollers 4 rollingly contact with the first cam face 6 and the second cam face 7 so that the relative movement of the rollers in an axial direction is converted into the relative rotation of the first disc 2 and the second disc 3 when the first disc 2 and the second disc 3 relatively move in the axial direction.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a roller cam mechanism that converts axial relative movement into relative rotation, a rotation transmission device using the roller cam mechanism, and a steer-by-wire vehicle steering device.

  Conventionally, as a rotation transmission device used for switching between a state in which rotation is transmitted from an input shaft to an output shaft and a state in which transmission of the rotation is interrupted, a motion conversion mechanism that converts relative movement in the axial direction into relative rotation is provided. Many used ones are used (for example, Patent Documents 1 and 2), and a ball cam mechanism is generally known as such a motion conversion mechanism.

  The ball cam mechanism includes a first disc and a second disc that are arranged opposite to each other in the axial direction, and a gap in the circumferential direction between the axial rear surface of the first disc and the axial front surface of the second disc. And a plurality of balls provided. A first cam groove is formed on the rear surface in the axial direction of the first disk, and the first cam groove gradually becomes deeper in one circumferential direction from the position of each ball. A second cam groove that is gradually deepened in the other circumferential direction is provided. The ball is incorporated between the first cam groove and the second cam groove. In the ball cam mechanism, when the first disk and the second disk are relatively moved in the axial direction, the ball rolls along the first cam groove and the second cam groove, so that the first disk and the second disk are relatively moved. Rotate.

  Further, in the ball cam mechanism described in Patent Document 2, in order to prevent wear and indentation, surface hardening treatment is performed on the ball and the member that the ball contacts (that is, the first disk and the second disk on which the ball is in rolling contact). Yes.

JP 2009-293679 A JP 2006-349108 A

  By the way, since the ball cam mechanism as described above uses a ball as a rolling element that converts the relative movement of the first disk and the second disk in the axial direction into relative rotation, a shaft is interposed between the first disk and the second disk. When a directional load is applied, a large surface pressure is generated at the contact portion between the first disk and the ball, and a large surface pressure is also generated at the contact portion between the second disk and the ball. Therefore, the ball cam mechanism has a problem that the magnitude of the axial load that can be loaded (load capacity) is relatively small. Also, since the ball has a shape that can roll in any direction, the contact position of the ball with the inner surface of the cam groove is difficult to stabilize. Therefore, the ball cam mechanism has a problem that the first disk or the second disk is easily inclined with respect to the direction perpendicular to the axis, and it is difficult to position the first disk and the second disk in parallel.

  The problem to be solved by the present invention is to provide a motion conversion mechanism capable of applying a large axial load between the first disk and the second disk and easily positioning the first disk and the second disk in parallel. It is to be.

In order to solve the above problems, the present invention provides a roller cam mechanism having the following configuration.
A first disk and a second disk which are arranged opposite to each other in the axial direction and are provided so as to be relatively rotatable;
A plurality of rollers spaced circumferentially between an axial rear surface of the first disk and an axial front surface of the second disk;
A first cam surface that is gradually displaced forward in the axial direction from the position of each roller toward one circumferential direction is provided on the rear surface in the axial direction of the first disk.
A second cam surface that is gradually displaced axially rearward from the position of each roller toward the other circumferential direction is provided on the front surface in the axial direction of the second disk.
The roller is configured to convert the relative movement in the axial direction into relative rotation between the first disk and the second disk when the first disk and the second disk are relatively moved in the axial direction. In rolling contact with the cam surface and the second cam surface;
Roller cam mechanism.

  In this case, since the roller is used as a rolling element that converts the relative movement of the first disk and the second disk in the axial direction into the relative rotation, the roller is disposed between the first disk and the second disk rather than the conventional ball cam mechanism. The surface pressure generated when an axial load is applied is small. Therefore, a large axial load can be applied between the first disk and the second disk. Further, since the roller has a shape that rolls in a certain direction, the contact position of the roller with respect to the cam surface becomes stable. Therefore, in the roller cam mechanism, the first disk and the second disk are not easily inclined with respect to the direction perpendicular to the axis, and it is easy to position the first disk and the second disk in parallel.

  Preferably, a roller holder is provided between the rear surface in the axial direction of the first disk and the front surface in the axial direction of the second disk so as to keep the circumferential intervals of the plurality of rollers constant.

  In this way, since the roller retainer keeps the intervals in the circumferential direction of the plurality of rollers constant, the axial displacement of each roller when the plurality of rollers roll can be made uniform. Therefore, when the first disk and the second disk rotate relative to each other, the parallelism between the first disk and the second disk can be stably maintained.

  The roller holder has a plurality of partial cylindrical portions that are opposed to each other in the circumferential direction with the rollers interposed therebetween and are formed in a circular arc shape along the outer periphery of the rollers, and the partial cylindrical portions. It is preferable to employ one comprising a connecting portion to be connected.

  In this case, since the partial cylindrical portion of the roller retainer maintains the orientation of the roller, when the roller rolls, the orientation of the center line of the roller is relative to the radial direction of the first disc and the second disc. Inclination can be prevented. Therefore, when the first disk and the second disk rotate relative to each other, it becomes possible to maintain the parallelism of the first disk and the second disk more stably.

  An outer diameter side flange extending in the circumferential direction so as to contact and guide the outer diameter side end surface of the roller to an outer diameter side end portion of at least one of the first cam surface and the second cam surface. It is preferable to provide a part.

  In this way, the movement range of the roller toward the outer diameter side is restricted by the outer diameter side flange, so that when the first disk and the second disk rotate relative to each other, the position of one of the rollers is the other roller. It is possible to reliably prevent a situation in which the first disk and the second disk are not parallel due to being shifted to the outer diameter side of the position.

  In this case, of the first cam surface and the second cam surface, the inner diameter side end surface of the roller is disposed on the inner diameter side end portion of the cam surface having the outer diameter side flange portion on the outer diameter side end portion. It is preferable to provide an inner diameter side flange that extends in the circumferential direction at the facing position.

  In this way, by restricting the movement range of both ends of the roller by the outer diameter side flange and the inner diameter side flange, it is possible to prevent the roller from being inclined with respect to the radial direction of the first disk and the second disk. It becomes possible to do. Therefore, when the first disk and the second disk rotate relative to each other, the parallelism between the first disk and the second disk can be stably maintained.

  It is preferable that the rollers are arranged at three locations at intervals in the circumferential direction.

  In this way, since the support between the first disk and the second disk becomes a three-point support, it is possible to receive an axial load equally by all the rollers, and any one of the rollers locally A situation where wear occurs can be prevented.

In the present invention, the following structure is provided as a rotation transmission device using the roller cam mechanism.
Outer ring,
An inner ring disposed inside the outer ring and supported to be rotatable relative to the outer ring;
A pair of engagement elements incorporated so as to oppose each other in the circumferential direction between an inner circumference of the outer ring and an outer circumference of the inner ring;
A first division supported so as to be relatively rotatable between an engagement position for engaging the pair of engagement elements between the outer ring and the inner ring and an engagement release position for releasing the engagement of the engagement elements. A cage and a second split cage;
An axial movement device for relatively moving the first divided holder and the second divided holder in the axial direction;
When the first split cage and the second split cage move relative to each other in the axial direction, the relative movement in the axial direction is converted into relative rotation between the first split cage and the second split cage. A rotation transmission device having a motion conversion mechanism for
A rotation transmission device using the roller cam mechanism as the motion conversion mechanism.

Moreover, in this invention, the thing of the following structures is provided as a vehicle steering device using said rotation transmission device.
A steering wheel,
A steering actuator that moves the pair of wheels so that the directions of the pair of left and right wheels change according to the steering angle of the steering wheel;
A steer-by-wire vehicle having a rotation transmission device that interrupts rotation transmission between the steering wheel and the steering actuator when normal, and transmits rotation between the steering wheel and the steering actuator when abnormal Steering device for
A steer-by-wire vehicle steering apparatus using the rotation transmission apparatus as the rotation transmission apparatus.

  Since the roller cam mechanism of the present invention uses a roller as a rolling element that converts the relative movement of the first disk and the second disk in the axial direction into relative rotation, the first disk and the second disk are more than the conventional ball cam mechanism. The surface pressure generated when an axial load is applied between them is small. Therefore, a large axial load can be applied between the first disk and the second disk. Further, since the roller has a shape that rolls in a certain direction, the contact position of the roller with respect to the cam surface becomes stable. Therefore, in this roller cam mechanism, the first disk and the second disk are not easily inclined with respect to the direction perpendicular to the axis, and it is easy to position the first disk and the second disk in parallel.

Sectional drawing which shows the roller cam mechanism of embodiment of this invention Sectional view along the line II-II in FIG. Enlarged view of the vicinity of the roller in FIG. Sectional view along line IV-IV in FIG. Sectional view along line VV in FIG. Sectional view along line VI-VI in FIG. The figure which shows the state which the roller shown in FIG. 3 rolled and moved on the 1st cam surface and the 2nd cam surface Sectional view along line VIII-VIII in FIG. Sectional view along line IX-IX in FIG. Sectional view along line XX in FIG. Sectional drawing which shows the example of the rotation transmission apparatus using the roller cam mechanism shown in FIG. Sectional drawing along the XII-XII line of FIG. Sectional drawing which expands and shows the vicinity of a pair of engaging element which opposes the circumferential direction on both sides of the elastic member of FIG. Sectional view along the line XIV-XIV in FIG. Sectional view along line XV-XV in FIG. FIG. 11 is a schematic diagram showing an example of a steer-by-wire vehicle steering device using the rotation transmission device shown in FIG.

  FIG. 1 shows a roller cam mechanism 1 according to an embodiment of the present invention. The roller cam mechanism 1 includes a first disk 2 and a second disk 3 that are disposed opposite to each other in the axial direction, a plurality of rollers 4 provided between the first disk 2 and the second disk 3, and And a roller holder 5 that holds the plurality of rollers 4.

  The first disk 2 is formed in an annular shape, and a first cam surface 6 is formed on the axial rear surface 2b. The second disk 3 is also formed in an annular shape, and a second cam surface 7 is formed on the front surface 3a in the axial direction. The roller 4 is provided between the axial rear surface 2b of the first disk 2 and the axial front surface 3a of the second disk 3, and is in rolling contact with both the first cam surface 6 and the second cam surface 7. Yes. The roller holder 5 is also provided between the axial rear surface 2 b of the first disk 2 and the axial front surface 3 a of the second disk 3. The first disk 2 and the second disk 3 are supported coaxially by a support portion (not shown) (for example, the outer peripheral portion of the input shaft 25 shown in FIG. 11) so as to be relatively rotatable on the same axis and relatively movable in the axial direction.

  As shown in FIG. 2, the rollers 4 are arranged at three locations at equal intervals in the circumferential direction. Each roller 4 has a conical shape in which the outer diameter gradually increases from the inner diameter side to the outer diameter side of the first disk 2 and the second disk 3. In this way, when the roller 4 is rolled in a state in which the direction of the center line of the roller 4 is held in the radial direction of the first disk 2 and the second disk 3, the first disk 2 and the second disk 3 Since the moving distance of the roller 4 on the outer diameter side is longer than the moving distance of the roller 4 on the inner diameter side, the roller 4 is smoothly revolved around the center O of the first disk 2 and the second disk 3. Therefore, it is possible to suppress slippage between the outer periphery of the roller 4 and the first cam surface 6 and the second cam surface 7.

  As shown in FIG. 3 and FIG. 6, when a conical roller 4 is employed, the roller 4 having a conical surface having an apex at the position of the center O of the first disk 2 and the second disk 3 is employed. can do. By doing so, it is possible to effectively reduce the slip when the roller 4 rolls on the first cam surface 6 and the second cam surface 7. The conical roller 4 is a virtual roller having a vertex at the position of the center O of the first disk 2 and the second disk 3 from the inner diameter side to the outer diameter side of the first disk 2 and the second disk 3. It is also possible to employ one having a substantially conical surface on the outer periphery that is asymptotic to a conical surface (ie, a virtual conical surface having the same shape as the outer peripheral surface of the roller 4 shown in FIG. 6).

  As shown in FIGS. 4 and 5, the roller retainer 5 includes a plurality of partial cylindrical portions 8 that are opposed to each other in the circumferential direction with the rollers 4 interposed therebetween, and an annular shape that connects the partial cylindrical portions 8. It consists of a connecting part 9. The partial cylindrical portion 8 is formed in a circular arc shape so as to follow the outer periphery of the roller 4, and by guiding the outer periphery of the roller 4 with this partial cylindrical portion 8, the direction of the center line of each roller 4 is set to the first direction. The disk 2 and the second disk 3 are held parallel to the radial direction. If the roller cage 5 is integrally formed with a synthetic resin in which reinforcing fibers are blended, weight reduction and economic efficiency can be improved. Further, when the roller cage 5 is formed of metal, the direction of the center line of the roller 4 is securely held even when a significantly large axial load is applied between the first disk 2 and the second disk 3, It is possible to prevent the roller 4 from being inclined with respect to the radial direction of the first disk 2 and the second disk 3.

  As shown in FIGS. 4 and 5, the first cam surface 6 is gradually displaced forward in the axial direction (upward in the figure) from the contact position of the roller 4 in one circumferential direction (leftward in the figure). It is formed to do. Further, the second cam surface 7 is formed so as to gradually displace from the contact position of the roller 4 in the axial direction rearward (downward in the drawing) toward the other circumferential direction (rightward in the drawing).

  As the first cam surface 6 as described above, the cross-sectional shape along the circumferential direction of the first disk 2 is inclined with respect to the direction perpendicular to the axis (the direction parallel to the axial rear surface 2b of the first disk 2 in the figure). It is possible to adopt a shape having a straight line. Similarly, the second cam surface 7 has a cross-sectional shape along the circumferential direction of the second disk 3 inclined with respect to a direction perpendicular to the axis (a direction parallel to the axial front surface 3a of the second disk 3 in the drawing). The thing of the shape used as a straight line is employable.

  The first cam surface 6 has an inclination with respect to the direction perpendicular to the axis in the inner diameter side cross section of the first disk 2 shown in FIG. 5, and the direction perpendicular to the axis in the outer diameter side cross section of the first disk 2 shown in FIG. It is made into the shape which becomes larger than the magnitude | size of the inclination with respect to. Further, the second cam surface 7 also has an inclination with respect to the direction perpendicular to the axis in the inner diameter side section of the second disk 3 shown in FIG. 5 in the axis in the outer diameter side section of the second disk 3 shown in FIG. The shape is larger than the inclination with respect to the perpendicular direction.

  As shown in FIGS. 4 and 5, the second cam surface 7 is a plane perpendicular to the axis of the second disk 3 (here, the axial rear surface 3 b) with the roller 4 in contact with the second cam surface 7. The axial distance h from the center of the roller 4 to the center of the roller 4 is constant regardless of the radial position, and as shown in FIGS. 8 and 9, the contact position of the roller 4 with respect to the second cam surface 7 has changed. Sometimes, the axial distance h ′ from the plane perpendicular to the axis (axial rear surface 3b) of the second disk 3 to the center of the roller 4 is formed to be constant regardless of the radial position.

  Similarly, the first cam surface 6 also has an axial direction from the plane perpendicular to the axis (front surface 2a in the axial direction) of the first disk 2 to the center of the roller 4 with the roller 4 being in contact with the first cam surface 6. Even when the distance is constant regardless of the radial position and the contact position of the roller 4 with respect to the first cam surface 6 changes, the roller 4 from the plane perpendicular to the axis (the axial front surface 2a) of the first disk 2 changes. It is formed so that the axial distance to the center is constant regardless of the radial position.

  As shown in FIG. 6, the first cam surface 6 has a shape in which a section along the radial direction of the first disk 2 is gradually displaced forward in the axial direction from the inner diameter side toward the outer diameter side. Further, the second cam surface 7 has a shape in which a cross section along the radial direction of the second disk 3 is gradually displaced rearward in the axial direction from the inner diameter side toward the outer diameter side. The first cam surface 6 and the second cam surface 7 are in line contact with the outer periphery of the roller 4 in a state where the first disk 2 and the second disk 3 are arranged in parallel.

As shown in FIGS. 6 and 10, the second cam surface 7 has a constant inclination angle θ ₂ with respect to the direction perpendicular to the axis in the cross section along the radial direction of the second disk 3 regardless of the position in the circumferential direction. It is formed as follows. Similarly, the first cam surface 6 is also formed such that the inclination angle θ ₁ with respect to the direction perpendicular to the axis in the cross section along the radial direction of the first disk 2 is constant regardless of the position in the circumferential direction.

  As shown in FIGS. 6 and 10, a first outer diameter side flange extending in the circumferential direction so as to contact and guide the outer diameter side end surface of the roller 4 at the outer diameter side end portion of the first cam surface 6. The first cam surface 6 is provided with a first inner diameter side flange 11 that extends in the circumferential direction at a position facing the inner diameter side end surface of the roller 4. Similarly, a second outer diameter side flange 12 extending in the circumferential direction so as to contact and guide the outer diameter side end surface of the roller 4 is provided at the outer diameter side end portion of the second cam surface 7. At the end on the inner diameter side of the second cam surface 7, a second inner diameter side flange 13 extending in the circumferential direction at a position facing the inner diameter side end face of the roller 4 is provided. The outer diameter side end surface of the roller 4 is a convex spherical surface.

  An operation example of the roller cam mechanism 1 will be described. In the state shown in FIGS. 4 and 5, when an axial load is applied between the first disk 2 and the second disk 3, the first cam surface 6 and the second cam are loaded. As the roller 4 rolls between the surfaces 7, the first disk 2 and the second disk 3 move relative to each other in the axial direction and approach each other. At this time, as shown in FIGS. 8 and 9, the first disk 2 moves relative to the roller 4 in one circumferential direction (rightward in the drawing) according to the rotation amount of the roller 4, and at the same time, 2 The disc 3 moves relative to the roller 4 in the other circumferential direction (leftward in the figure). For this reason, the first disk 2 and the second disk 3 rotate relative to each other in accordance with the amount of relative movement in the axial direction. In this way, the roller cam mechanism 1 converts the relative movement of the first disk 2 and the second disk 3 in the axial direction into the relative rotation of the first disk 2 and the second disk 3.

  The roller cam mechanism 1 uses the roller 4 as a rolling element that converts the relative movement of the first disk 2 and the second disk 3 in the axial direction into relative rotation, so that the first disk 2 and the second disk 3 are larger than the conventional ball cam mechanism. The surface pressure generated when an axial load is applied between the two disks 3 is small. Therefore, a large axial load can be applied between the first disk 2 and the second disk 3. Further, the surface hardening process of the first disk 2 and the second disk 3 can be omitted, and the cost is low.

  Further, unlike the ball, the roller 4 has a shape that rolls in a certain direction, so that the contact position of the roller 4 with respect to the cam surfaces 6 and 7 becomes stable. Therefore, in this roller cam mechanism 1, the first disk 2 or the second disk 3 is not easily inclined with respect to the direction perpendicular to the axis, and it is easy to position the first disk 2 and the second disk 3 in parallel.

  Further, the roller cam mechanism 1 has a roller holder 5 that keeps the circumferential intervals of the plurality of rollers 4 constant, so that when the plurality of rollers 4 roll, the circumferential movement distance of each roller 4 is increased. It is always equal and the axial displacement of each roller 4 is uniform. Therefore, when the first disk 2 and the second disk 3 rotate relative to each other, it is possible to stably maintain the parallelism of the first disk 2 and the second disk 3.

  Further, in this roller cam mechanism 1, since the partial cylindrical portion 8 of the roller holder 5 holds the orientation of the roller 4, when the roller 4 rolls, the orientation of the center line of the roller 4 is the first disk 2 and Inclination with respect to the radial direction of the second disk 3 can be prevented. Therefore, when the first disk 2 and the second disk 3 rotate relative to each other, it is possible to maintain the parallelism of the first disk 2 and the second disk 3 more stably.

  Further, the roller cam mechanism 1 has a first outer diameter side flange portion 10 and a second outer diameter side flange portion 12 that restrict the movement range of the roller 4 toward the outer diameter side. When the second disk 3 rotates relatively, it is ensured that the position of one of the rollers 4 is shifted to the outer diameter side of the position of the other roller 4 and the first disk 2 and the second disk 3 become non-parallel. It is possible to prevent.

  The roller cam mechanism 1 includes a first outer diameter side flange 10 and a second outer diameter side flange 12, and a first inner diameter side flange 11 and a second inner diameter side flange 13, which are rollers 4. By restricting the movement range of both ends of the first and second discs, the roller 4 is prevented from being inclined with respect to the radial direction of the first disc 2 and the second disc 3. Therefore, when the first disk 2 and the second disk 3 rotate relative to each other, it is possible to stably maintain the parallelism of the first disk 2 and the second disk 3.

  Further, in this roller cam mechanism 1, the rollers 4 are arranged at three positions at intervals in the circumferential direction, and the support between the first disk 2 and the second disk 3 is supported at three points. 4 can receive an axial load equally, and it is possible to prevent any one of the rollers 4 from being locally worn.

  In the above-described embodiment, the example in which the conical roller 4 is employed to reduce the slip with respect to the first cam surface 6 and the second cam surface 7 has been described. However, the cylindrical roller 4 or the needle roller 4 is used. May be adopted.

  In the above embodiment, an example in which three rollers 4 are used has been described. However, the number of rollers 4 may be two, and an axial load applied between the first disk 2 and the second disk 3. If the size of the roller 4 is remarkably large, the number of rollers 4 may be four or more.

  FIG. 11 shows a rotation transmission device 20 using the roller cam mechanism 1 described above. The rotation transmission device 20 is a clutch that switches between a state where rotation is transmitted from the input side to the output side and a state where transmission of the rotation is interrupted. The rotation transmission device 20 includes an outer ring 21, an inner ring 22 disposed inside the outer ring 21, and cylindrical engagement members 23 a and 23 b incorporated between the inner periphery of the outer ring 21 and the outer periphery of the inner ring 22, It has the engagement element holder | retainer 24 which hold | maintains these engagement elements 23a and 23b. An input shaft 25 is connected to the inner ring 22, and an output shaft 26 is connected to the outer ring 21. The input shaft 25 and the output shaft 26 are arranged on the same axis.

  The input shaft 25 and the inner ring 22 are serrated and fitted so that both rotate integrally. The input shaft 25 and the inner ring 22 may be formed as a seamless integral member.

  The output shaft 26 and the outer ring 21 are formed as a seamless integral member so that both rotate integrally. The output shaft 26 and the outer ring 21 may be formed as separate members, and both may be connected by serration fitting or the like. A rolling bearing 27 is incorporated between the outer ring 21 and the inner ring 22 to support the inner ring 22 so as to be rotatable relative to the outer ring 21. A rolling bearing 29 that rotatably supports the output shaft 26 is incorporated in an end portion on the output shaft 26 side of the cylindrical housing 28 that accommodates the constituent members of the rotation transmitting device 20.

  As shown in FIGS. 12 and 13, a plurality of cam surfaces 30 a and 30 b are provided on the outer periphery of the inner ring 22 at equal intervals in the circumferential direction. The cam surfaces 30a and 30b are composed of a front cam surface 30a and a rear cam surface 30b disposed rearward in the forward rotation direction of the inner ring 22 with respect to the front cam surface 30a. A cylindrical surface 31 is provided on the inner periphery of the outer ring 21 so as to face the cam surfaces 30a and 30b in the radial direction.

  The pair of engagement elements 23a and 23b are incorporated between the cam surfaces 30a and 30b and the cylindrical surface 31 so as to face each other in the circumferential direction with the elastic member 32 interposed therebetween. Of the pair of engaging elements 23a and 23b, the engaging element 23a on the front side in the forward rotation direction is incorporated between the front cam surface 30a and the cylindrical surface 31, and the engaging element 23b on the rear side in the normal rotation direction is connected with the rear cam surface 30b. It is incorporated between the cylindrical surfaces 31. The elastic member 32 presses each engagement element 23a, 23b in a direction in which the distance between the pair of engagement elements 23a, 23b is increased.

  The front cam surface 30a is formed such that the radial distance from the cylindrical surface 31 gradually decreases from the position of the engagement element 23a toward the front in the forward rotation direction. The rear cam surface 30b is formed such that the radial distance between the rear cam surface 30b and the cylindrical surface 31 gradually decreases from the position of the engaging element 23b toward the rear in the forward rotation direction. In the figure, the front cam surface 30a and the rear cam surface 30b are formed so as to be separate planes inclined in opposite directions, but the front cam surface 30a and the rear cam surface 30b are in a single plane forward rotation. It is also possible to form on the same plane so that the front portion in the direction is the front cam surface 30a and the rear portion is the rear cam surface 30b. Further, the front cam surface 30a and the rear cam surface 30b can be curved surfaces. However, if the front cam surface 30a and the rear cam surface 30b are flat as shown in the figure, the processing cost can be reduced.

  As shown in FIGS. 11 to 13, the engaging cage holder 24 is a first division that supports one engaging member 23 a of the pair of engaging members 23 a and 23 b that are opposed to each other in the circumferential direction with the elastic member 32 therebetween. It consists of a cage 24A and a second split cage 24B that supports the other engaging element 23b. The first divided holder 24 </ b> A is formed integrally with the first disk 2 of the roller cam mechanism 1. The second divided holder 24 </ b> B is formed integrally with the second disk 3 of the roller cam mechanism 1. The first split holder 24 </ b> A and the second split holder 24 </ b> B have a pair of engagement elements such that the distance between the pair of engagement elements 23 a and 23 b changes according to the relative rotation of the first disk 2 and the second disk 3. 23a and 23b are individually supported.

  24 A of 1st division | segmentation holder | retainers have the some disk part 33a arrange | positioned at intervals in the circumferential direction, and the 1st disk 2 which connects the edge parts of these pillar parts 33a. Similarly, the 2nd division | segmentation holder | retainer 24B also has the some pillar part 33b arrange | positioned at intervals in the circumferential direction, and the 2nd disk 3 which connects the edge parts of these pillar parts 33b.

  The column part 33a of the first divided holder 24A and the column part 33b of the second divided holder 24B are provided with a pair of engaging elements 23a, 23b facing each other in the circumferential direction with the elastic member 32 therebetween from both sides in the circumferential direction. It is inserted between the inner periphery of the outer ring 21 and the outer periphery of the inner ring 22 so as to be sandwiched.

  The first disk 2 and the second disk 3 are supported on the outer periphery of the input shaft 25 so as to be relatively rotatable. As a result, the first split cage 24A and the second split cage 24B increase the distance between the pair of engagement elements 23a and 23b, thereby engaging each engagement element 23a between the cylindrical surface 31 and the cam surfaces 30a and 30b. , 23b and the distance between the pair of engagement elements 23a, 23b is reduced to release the engagement of the engagement elements 23a, 23b between the cylindrical surface 31 and the cam surfaces 30a, 30b. It can move between the disengagement positions. The first disk 2 is supported in the axial direction by an annular projection 35 fixedly provided on the outer periphery of the input shaft 25 via a thrust bearing 34, thereby restricting movement in the axial direction.

  As shown in FIG. 14, a spring holder 36 is fixed to the side surface of the inner ring 22. The spring holder 36 has a stopper piece 37 positioned between both pillar portions 33a and 33b that face each other in the circumferential direction with the pair of engaging elements 23a and 23b interposed therebetween. In the stopper piece 37, when both the pillar portions 33a and 33b are moved in the direction of narrowing the distance between the pair of engaging elements 23a and 23b, the edges on both sides of the stopper piece 37 receive the pillar portions 33a and 33b. This prevents the elastic member 32 between the pair of engagement elements 23a and 23b from being excessively compressed and broken, and also relates each engagement to the inner ring 22 when the distance between the pair of engagement elements 23a and 23b is narrowed. It is possible to make the positions of the couplers 23a and 23b constant.

  As shown in FIG. 15, the spring holder 36 includes a spring holding piece 38 that holds the elastic member 32. The spring holding piece 38 is formed integrally with the stopper piece 37 so as to extend in the axial direction between the inner circumference of the outer ring 21 and the outer circumference of the inner ring 22. The spring holding piece 38 is disposed so as to face the spring support surface 39 (see FIG. 13) formed between the front cam surface 30a and the rear cam surface 30b on the outer periphery of the inner ring 22 in the radial direction. A concave portion 40 for accommodating the elastic member 32 is formed on the surface of the spring holding piece 38 facing the spring support surface 39. The elastic member 32 is a coil spring. The spring holding piece 38 restricts the movement of the elastic member 32 by the recess 40, thereby preventing the elastic member 32 from dropping in the axial direction from between the inner periphery of the outer ring 21 and the outer periphery of the inner ring 22. .

  As shown in FIG. 11, the rotation transmission device 20 includes an axial movement device 41 that relatively moves the first divided holder 24A and the second divided holder 24B in the axial direction, and the first divided holder 24A. Roller cam as a motion conversion mechanism for converting the relative movement in the axial direction into the relative rotation of the first divided holder 24A and the second divided holder 24B when the second divided holder 24B moves in the axial direction. Mechanism 1. The axial direction moving device 41 includes an armature 42 connected to the second divided holder 24B, a rotor 43 disposed so as to face the armature 42 in the axial direction, and an electromagnet 44 that attracts the armature 42 to the rotor 43 by energization. It consists of.

  The armature 42 includes an annular disk portion 45 and a cylindrical portion 46 that is integrally formed so as to extend in the axial direction from the outer periphery of the disk portion 45. The cylindrical portion 46 of the armature 42 is fitted to the outer periphery of the second split holder 24B with a tight margin, and by this fitting, the armature 42 moves integrally with the second split holder 24B in the axial direction. In this way, it is connected to the second divided holder 24B. The armature 42 is supported by a cylindrical surface 47 provided on the outer periphery of the input shaft 25 so as to be rotatable and movable in the axial direction. Here, the armature 42 is supported so as to be movable in the axial direction at two locations separated in the axial direction (that is, the inner circumference of the armature 42 and the inner circumference of the second disk 3), so that the posture of the armature 42 is perpendicular to the axis. Is prevented from tilting.

  The rotor 43 is disposed between the armature 42 and the electromagnet 44. Further, the rotor 43 is supported on the outer periphery of the input shaft 25 so as not to move relative to either the axial direction or the circumferential direction by fitting to the outer periphery of the input shaft 25 with a tightening margin. The rotor 43 and the armature 42 are made of a ferromagnetic metal.

  The armature 42 is urged in a direction away from the rotor 43 by the force of the elastic member 32. That is, the force by which the elastic member 32 shown in FIG. 12 presses each engagement element 23a, 23b in the direction in which the distance between the pair of engagement elements 23a, 23b is increased is the first divided holder 24A and the second divided holder 24B. To communicate. The circumferential force received by the first divided holder 24A and the second divided holder 24B is the direction in which the first and second disks 2 and 3 are separated in the axial direction by the roller cam mechanism 1 shown in FIG. However, since the first disk 2 is restricted from moving forward in the axial direction by the thrust bearing 34 and the annular protrusion 35, the force of the elastic member 32 causes the second disk 3 to move rearward in the axial direction. Acts as an energizing force. Here, since the armature 42 is fixed to the second divided holder 24 </ b> B integral with the second disk 3, the armature 42 is eventually rotated by the force transmitted from the elastic member 32 via the roller cam mechanism 1. It is in a state of being biased in a direction away from 43.

  An operation example of the rotation transmission device 20 will be described.

  As shown in FIG. 11, when energization of the electromagnet 44 is stopped, the rotation transmission device 20 is in an engaged state in which rotation is transmitted between the outer ring 21 and the inner ring 22. That is, the armature 42 is separated from the rotor 43 by the force of the elastic member 32 when the energization to the electromagnet 44 is stopped. Further, at this time, the front engaging element 23a in the forward rotation direction causes the inner circumference of the outer ring 21 by the force of the elastic member 32 that presses the engaging elements 23a and 23b in the direction in which the distance between the pair of engaging elements 23a and 23b increases. Between the cylindrical surface 31 of the inner ring 22 and the front cam surface 30 a on the outer periphery of the inner ring 22, and the engagement element 23 b on the rear side in the normal rotation direction is connected to the cylindrical surface 31 of the outer ring 21 and the inner ring 22. It is in the state of waiting for engagement with the rear cam surface 30b on the outer periphery. In this state, when the inner ring 22 rotates in the forward direction, the engagement element 23b on the rear side in the forward rotation direction engages between the cylindrical surface 31 and the rear cam surface 30b, and from the inner ring 22 via the engagement element 23b. The rotation is transmitted to the outer ring 21. When the inner ring 22 rotates in the reverse rotation direction, the forward engagement element 23a in the forward rotation direction engages between the cylindrical surface 31 and the front cam surface 30a, and rotates from the inner ring 22 to the outer ring 21 via the engagement element 23a. Communicate.

  On the other hand, when the electromagnet 44 is energized, the rotation transmission device 20 is in the disengaged state (idling state) in which the rotation transmission between the outer ring 21 and the inner ring 22 is blocked. That is, when the electromagnet 44 is energized, the armature 42 is attracted to the rotor 43, and in conjunction with the operation of the armature 42, the second disk 3 of the second divided holder 24B is moved to the first of the first divided holder 24A. It moves in the axial direction toward the disk 2. At this time, the roller 4 of the roller cam mechanism 1 rolls along the first cam surface 6 and the second cam surface 7, whereby the first divided holder 24 </ b> A and the second divided holder 24 </ b> B rotate relative to each other. . Then, due to the relative rotation of the first divided holder 24A and the second divided holder 24B, a pair of the column portion 33a of the first divided holder 24A and the column portion 33b of the second divided holder 24B are paired. Each of the engagement elements 23a and 23b is pressed in a direction in which the distance between the engagement elements 23a and 23b is reduced, and as a result, the engagement state of the front engagement element 23a in the forward rotation direction (the forward engagement element 23a and the forward rotation direction) There is a minute gap between the cylindrical surfaces 31, but when the inner ring 22 rotates in the reverse direction, the engagement element 23a immediately engages between the cylindrical surface 31 and the front cam surface 30a) and the normal rotation direction. Engagement standby state of the rear engagement element 23b (there is a minute gap between the rear engagement element 23b in the forward rotation direction and the cylindrical surface 31, but when the inner ring 22 rotates in the forward rotation direction, the engagement element 23b is immediately Engage between the cylindrical surface 31 and the rear cam surface 30b. State) is also released state. In this state, even if rotation is input to the inner ring 22, the rotation is not transmitted from the inner ring 22 to the outer ring 21, and the inner ring 22 idles.

  The rotation transmission device 20 is used in, for example, a vehicle steering device shown in FIG. This vehicle steering device is a steer-by-wire vehicle steering device that converts the steering angle of the steering wheel 50 by the driver into an electrical signal and steers the left and right wheels 51 based on the electrical signal.

  The vehicle steering apparatus includes a steering wheel 50, a steering actuator 52 that moves the pair of wheels 51 so that the directions of the pair of left and right wheels change according to the steering angle of the steering wheel 50, the steering wheel 50, and the steering And a rotation transmission device 20 incorporated in the middle of the rotation transmission path between the actuators 52. The rotation transmission device 20 interrupts transmission of rotation between the steering wheel 50 and the steering actuator 52 when normal, and transmits rotation between the steering wheel 50 and the steering actuator 52 when there is an abnormality such as power loss. Functions as a backup clutch. A reaction force actuator 53 that applies a steering reaction force to the steering wheel 50 in accordance with the behavior of the vehicle is connected to the steering wheel 50.

  In the rotation transmitting device 20, the input shaft 25 is connected to the shaft 55 on the steering wheel 50 side via the shaft coupling 54, and the output shaft 26 is connected to the shaft 57 on the steering actuator 52 side via the shaft coupling 56. ing.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

DESCRIPTION OF SYMBOLS 1 Roller cam mechanism 2 1st disk 2b Axial rear surface 3 2nd disk 3a Axial front surface 4 Roller 5 Roller retainer 6 First cam surface 7 Second cam surface 8 Partial cylindrical part 9 Connection part 10 First outside Diameter side flange 11 First inner diameter side flange 12 Second outer diameter side flange 13 Second inner diameter side flange 21 Outer ring 22 Inner rings 23a, 23b Engagement element 24A First division holder 24B Second division Cage 41 Axial moving device 50 Steering wheel 51 Wheel 52 Steering actuator

Claims (8)

A first disk (2) and a second disk (3) which are arranged opposite to each other in the axial direction and provided so as to be relatively rotatable;
A plurality of rollers (4) spaced circumferentially between an axial rear surface (2b) of the first disk (2) and an axial front surface (3a) of the second disk (3); Have
On the axial rear surface (2b) of the first disk (2), there is a first cam surface (6) that is gradually displaced axially forward from the position of each roller (4) toward one circumferential direction. Provided,
A second cam surface (7) that gradually displaces axially rearward from the position of each roller (4) toward the other circumferential direction on the axial front surface (3a) of the second disk (3). Provided,
When the first disk (2) and the second disk (3) move relative to each other in the axial direction, the roller (4) moves in the axial direction relative to the first disk (2) and the second disk. Rolling contact with the first cam surface (6) and the second cam surface (7) so as to convert to the relative rotation of (3),
Roller cam mechanism.   Between the axial rear surface (2b) of the first disk (2) and the axial front surface (3a) of the second disk (3), the circumferential intervals of the plurality of rollers (4) are kept constant. The roller cam mechanism according to claim 1, further comprising a roller holder.   The roller holder (5) has a plurality of partial cylindrical portions that are opposed to each other in the circumferential direction with the rollers (4) interposed therebetween, and are formed in a circular arc shape along the outer periphery of the roller (4). The roller cam mechanism according to claim 2, comprising: (8) and a connecting portion (9) for connecting the partial cylindrical portions (8).   An outer diameter side end surface of the roller (4) at an outer diameter side end portion of at least one cam surface (6, 7) of the first cam surface (6) and the second cam surface (7). The roller cam mechanism according to any one of claims 1 to 3, further comprising an outer diameter side flange portion (10, 12) extending in a circumferential direction so as to contact and guide the roller.   Of the first cam surface (6) and the second cam surface (7), the inner diameter of the cam surface (6, 7) having the outer diameter side flange (10, 12) at the outer diameter side end. The roller cam mechanism according to claim 4, wherein an inner diameter side flange (11, 13) extending in a circumferential direction at a position facing the inner diameter side end face of the roller (4) is provided at an end on the side.   The roller cam mechanism according to any one of claims 1 to 5, wherein the roller (4) is disposed at three positions at intervals in the circumferential direction. An outer ring (21),
An inner ring (22) disposed inside the outer ring (21) and supported to be rotatable relative to the outer ring (21);
A pair of engagement elements (23a, 23b) incorporated so as to oppose each other in the circumferential direction between the inner periphery of the outer ring (21) and the outer periphery of the inner ring (22);
An engagement position for engaging the pair of engagement elements (23a, 23b) between the outer ring (21) and the inner ring (22), and an engagement release for releasing engagement of the engagement elements (23a, 23b) A first split holder (24A) and a second split holder (24B) supported so as to be rotatable relative to each other;
An axial movement device (41) for relatively moving the first divided holder (24A) and the second divided holder (24B) in the axial direction;
When the first split holder (24A) and the second split holder (24B) move relative to each other in the axial direction, the relative movement in the axial direction is changed between the first split holder (24A) and the second split holder (24A). A rotation transmission device having a motion conversion mechanism (1) that converts the relative rotation of the split cage (24B).
A rotation transmission device using the roller cam mechanism according to any one of claims 1 to 6 as the motion conversion mechanism (1). A steering wheel (50);
A steering actuator (52) for moving the pair of wheels (51) so that the directions of the pair of left and right wheels (51) change according to the steering angle of the steering wheel (50);
When normal, the transmission of rotation between the steering wheel (50) and the steering actuator (52) is cut off, and when abnormal, the rotation is transmitted between the steering wheel (50) and the steering actuator (52). In a steer-by-wire vehicle steering apparatus having a rotation transmission device (20) that
A steer-by-wire vehicle steering device using the rotation transmission device according to claim 7 as the rotation transmission device (20).

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