JP2009121645A - Cam mechanism and driving force transmission device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cam mechanism and a driving force transmission device having the cam mechanism, capable of accurately generating thrust with a simple constitution. <P>SOLUTION: This cam mechanism 15 is composed of a main cam 18 and a pilot cam 19 mutually relatively rotatable on the same axis, and a cam-follower 20 sandwiched by first and second cam grooves 23 and 25 formed in a plurality on these opposed surfaces 22 and 24, respectively. The first cam groove 23 is formed by inclining its forward directional cam part 28a by a first predetermined angle to the peripheral direction, and is formed by inclining its inverse directional cam part 18b by a second predetermined angle to the peripheral direction. The second cam groove 25 is formed by inclining its forward directional cam part 29a by a third predetermined angle different from the first predetermined angle to the peripheral direction, and is formed by inclining its inverse directional cam part 29b by a fourth predetermined angle different from the second predetermined angle to the peripheral direction, when seeing through from one side in the axial direction. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a cam mechanism and a driving force transmission device including the cam mechanism.

  Conventionally, a cylindrical first rotating body that is rotated by input of a driving force, a shaft-shaped second rotating body that is coaxially disposed rotatably in the cylinder of the first rotating body, the first rotating body, and the first rotating body There is a driving force transmission device provided with a clutch mechanism that is provided between two rotating bodies and that couples both of them to transmit torque. In the clutch mechanism used in such a driving force transmission device, each clutch plate is frictionally engaged by the cam mechanism in which axial thrust is generated by the relative rotation of the first rotating body and the second rotating body, and the first The rotating body and the second rotating body are coupled so as to be able to transmit torque. In general, the cam mechanism includes a first cam member and a second cam member that can rotate relative to each other on the same rotation shaft, and a plurality of first cams formed on respective opposing surfaces of the first cam member and the second cam member. The cam follower is sandwiched between the groove and the second cam groove. The first and second cam grooves are the deepest part having the deepest axial depth, and the forward cam part and the reverse cam having a shallower depth along the longitudinal direction from the deepest part to both sides in the circumferential direction. The forward cam portion and the reverse cam portion are formed along the circumferential direction.

As shown in FIG. 6A, in such a cam mechanism 51, the first cam member 52 and the second cam member 53 are in the neutral position (the deepest portion 55 of the first cam groove 54 and the second cam groove 56). The cam follower 58 is positioned at the deepest portions 55 and 57 in a state where the deepest portion 57 is located. In this state, the first cam member 52 and the second cam member 53 are in the closest state, and no axial thrust is generated. In the cam mechanism 51, as shown in FIG. 6B, the first cam member 52 and the second cam member 53 rotate relative to each other, and the cam follower 58 rolls to move the forward cam portions 59a, 60a or reverse. By riding on the directional cam portions 59b and 60b, the first cam member 52 and the second cam member 53 are separated from each other, and axial thrust is generated. Incidentally, since the first cam groove 54 and the second cam groove 56 face each other in a state where the first cam member 52 and the second cam member 53 are relatively rotated, the first cam member 52 and the second cam member 53 are opposed to each other. Due to dimensional variations and the like, the cam follower 58 may move in the first and second cam grooves 54 and 56 as shown in FIG. As a result, for example, one of the plurality of cam followers 58 may move to the deepest portion 55 of the first cam member 52 in a state where the first cam member 52 and the second cam member 53 are relatively rotated. Then, even if the first cam member 52 and the second cam member 53 return to the neutral position, the cam follower 58 does not roll to the deepest portion 57 of the second cam groove 56 as shown in FIG. The first cam member 52 and the second cam member 53 are partially separated from each other, and there is a concern that axial thrust is generated. Therefore, the first cam member 52 and the second cam member 53 are relatively rotated by using a retainer that holds each cam follower 58 at a predetermined interval in the circumferential direction as in the cam mechanism described in Patent Document 1, for example. Thus, the cam followers 58 are prevented from moving relative to each other, and thrust is generated with high accuracy according to the relative rotation amount.
Japanese Utility Model Publication No. 63-150123

  By the way, since the conventional configuration requires a retainer, the number of parts and the number of work steps are increased. Further, although the retainer can prevent the relative movement of the cam followers 58, it cannot prevent all the cam followers from moving in the same direction at the same time. Even if the retainer is used, for example, as shown in FIG. There is a risk of being in a bad state.

  However, if the plurality of cam followers 58 are not held by the retainers, in addition to the case where the plurality of cam followers move in the same direction at the same time, as described above, for example, the plurality of cam followers 58 are rotated in a state where the first and second cam members 53 are relatively rotated. One of the cam followers 58 may move in the first and second cam grooves 54 and 56. As a result, for example, there is a problem that thrust is generated in a state where the first cam member 52 and the second cam member 53 are in the neutral position, and there is a possibility that the thrust cannot be accurately generated according to the relative rotation amount. When such a cam mechanism is used in a driving force transmission device, for example, torque is transmitted in an unintended state, and there is a problem that the transmission torque cannot be controlled with high accuracy.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide a cam mechanism capable of generating thrust accurately with a simple configuration and a driving force transmission device including the cam mechanism. There is to do.

  In order to achieve the above object, according to the first aspect of the present invention, there is provided a first cam member and a second cam member, which are coaxially rotatable relative to each other, and each facing of the first cam member and the second cam member. A plurality of first cam grooves formed on the surface and a cam follower sandwiched between the second cam grooves. The first cam groove includes a deepest portion having a deepest axial depth, and a circumferential portion extending from the deepest portion. A forward cam portion formed on one side of the direction and having a shallow depth along the longitudinal direction; and a reverse cam portion formed on the other side in the circumferential direction from the deepest portion and having a shallow depth along the longitudinal direction; And the second cam groove includes a deepest portion having a deepest axial depth, and a forward cam formed on the other side in the circumferential direction from the deepest portion and having a shallow depth along the longitudinal direction. And the depth formed along the longitudinal direction is formed on one side in the circumferential direction from the deepest portion. The cam follower rides on the forward cam portion or the reverse cam portion by the relative rotation of the first cam member and the second cam member to generate axial thrust. The forward cam portion of the first cam groove is inclined at a first predetermined angle with respect to the circumferential direction, and the reverse cam portion of the first cam groove is The forward cam portion of the second cam groove is inclined at a third predetermined angle different from the first predetermined angle with respect to the circumferential direction, and the second cam groove The reverse direction cam portion is formed so as to be inclined at a fourth predetermined angle different from the second predetermined angle with respect to the circumferential direction.

  According to the above configuration, the forward cam portion of the first cam groove sandwiching the cam follower with the first cam member and the second cam member rotating relative to each other when seen through from one side in the axial direction. The forward cam portion of the second cam portion is formed to be inclined with respect to the circumferential direction at a different angle. Further, the reverse cam portion of the first cam groove and the reverse cam portion of the second cam portion are formed to be inclined with respect to the circumferential direction at different angles. As a result, the first and second cam grooves are opposed to each other in a state where the first cam member and the second cam member are relatively rotated, and the cam follower is located at a position where the first cam groove and the second cam groove intersect. Is pinched. For this reason, the longitudinal direction of the first cam groove and the longitudinal direction of the second cam groove face in different directions with the first cam member and the second cam member rotating relative to each other, and the cam follower cannot move from the intersecting position. Accordingly, as in the conventional case, the cam followers are prevented from relatively moving in a state where the first cam member and the second cam member are rotated relative to each other without using a retainer that holds a plurality of cam followers at a predetermined interval. At the same time, all cam followers are prevented from moving in the same direction at the same time. As a result, for example, the generation of thrust in the neutral position can be reliably prevented, and the thrust can be generated with high accuracy according to the relative rotation amount between the first cam member and the second cam member with a simple configuration. Is possible. Moreover, since it is not necessary to use a retainer, the number of parts and work man-hours can be reduced. Furthermore, since the forward cam portion and the reverse cam portion are formed in the first and second cam grooves, respectively, regardless of the direction of relative rotation between the first cam member and the second cam member. It is possible to generate axial thrust.

  The invention according to claim 2 is characterized in that, in the cam mechanism according to claim 1, the first and second cam grooves are formed so as not to overlap each other in the radial direction. . According to the above configuration, the first and second cam grooves are formed so as not to overlap a plurality of rows (two rows or more) along the radial direction on each facing surface. The first and second cam members can be reduced in size in the radial direction compared to the case where a plurality of rows are formed in the radial direction.

  The gist of the invention described in claim 3 is that, in the cam mechanism according to claim 1 or 2, the forward cam portion and the reverse cam portion are formed linearly. According to the said structure, compared with the case where a forward cam part and a reverse cam part are formed in complicated shapes, such as curve shape, formation of a 1st and 2nd cam groove becomes easy, for example.

  According to a fourth aspect of the present invention, in the cam mechanism according to any one of the first to third aspects, the deepest portion of each of the first and second cam grooves is the outermost radial direction. The summary is as follows.

  The cam mechanism is used, for example, in a driving force transmission device that changes a driving force distribution between main driving wheels and auxiliary driving wheels of a four-wheel drive vehicle. When the vehicle travels, such a driving force transmission device rotates, so that centrifugal force acts on the cam mechanism, and the cam follower tends to move outward in the radial direction. According to the above configuration, the deepest portions of the first and second cam grooves are formed so as to be the outermost radial outsides of the first and second cam grooves. It tries to move to the deepest part of the second cam groove. Therefore, in a state where the first cam and the second cam member are in the neutral position, the cam follower is settled to the deepest portion, and the thrust is prevented from being generated when the first cam and the second cam are not relatively rotated. .

  According to a fifth aspect of the present invention, a cylindrical first rotating member that is rotated by input of a driving force, and a second rotation that is rotatable coaxially with the first rotating member inside the first rotating member. And a clutch mechanism that is disposed between the first rotating member and the second rotating member, and is connected to the first rotating member and the second rotating member so as to transmit torque by being pressed in the axial direction. The cam mechanism according to any one of claims 1 to 4, wherein the cam mechanism is pressed in the axial direction according to relative rotation of the first rotating member and the second rotating member. The gist.

  According to the above configuration, the thrust can be generated with high accuracy by the cam mechanism in accordance with the relative rotation amount between the first cam member and the second cam member. For example, torque is transmitted in an unintended state. Is prevented, and the transmission torque is accurately controlled.

  ADVANTAGE OF THE INVENTION According to this invention, the cam mechanism which can generate a thrust accurately with a simple structure, and the drive force transmission apparatus provided with this cam mechanism can be provided.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of the invention will be described with reference to the drawings.
As shown in FIG. 1A, the driving force transmission device 1 includes a bottomed cylindrical front housing 3 that is rotatably accommodated in a coupling case 2, and is rotatable within the cylinder of the front housing 3. And an axial inner shaft 4 arranged coaxially.

  The front housing 3 as the first rotating member is rotatably supported by the ball bearing 5 with its bottom 3a (left side in the figure) exposed to the outside of the coupling case 2 and its open end 3b. Is fitted with an annular rear housing 6. The inner shaft 4 as the second rotating member is rotatably supported by a needle bearing 7 provided on the inner periphery of the rear housing 6 and a ball bearing 8 provided in a cylinder of the front housing 3. The inside of the cylinder of the front housing 3 is provided by a fitting portion between the front housing 3 and the rear housing 6 and seal members 9 and 10 provided between the inner periphery of the rear housing 6 and the outer periphery of the inner shaft 4. Sealed and lubricating oil is contained in the cylinder.

  The bottom portion 3 a of the front housing 3 is connected to a flange portion (not shown) provided on a propeller shaft (not shown) by a bolt 11. Thereby, the front housing 3 rotates by the input of the driving force which the engine (not shown) which is a drive source generate | occur | produces. Further, a connecting portion (spline fitting portion) 12 (not shown) with a rear differential (not shown) is formed on the inner periphery of the shaft end (right side in the figure) of the inner shaft 4 supported on the needle bearing 7. Yes. That is, when the vehicle is mounted on the driving force transmission device 1, the front housing 3 is connected to the front wheel side which is the main driving wheel, and the inner shaft 4 is connected to the rear wheel side which is the auxiliary driving wheel.

  Further, a main clutch 13 capable of connecting the front housing 3 and the inner shaft 4 so as to be able to transmit torque is provided in the cylinder of the front housing 3, and a pilot clutch is provided in the axial direction of the main clutch 13 and on the rear housing 6 side. 14 are juxtaposed. A cam mechanism 15 is provided between the main clutch 13 and the pilot clutch 14.

  The main clutch 13 serving as a clutch mechanism employs a multi-plate friction clutch in which a plurality of outer clutch plates 16 and inner clutch plates 17 that are provided so as to be movable in the axial direction are alternately arranged. Specifically, each outer clutch plate 16 is spline-fitted to the inner periphery of the front housing 3 and each inner clutch plate 17 is spline-fitted to the outer periphery of the inner shaft 4, so that each outer clutch plate 16 can move in the axial direction and has a corresponding front. The housing 3 or the inner shaft 4 is provided so as to be integrally rotatable. The main clutch 13 connects the front housing 3 and the inner shaft 4 so that torque can be transmitted by the outer clutch plates 16 and the inner clutch plates 17 being pressed in the axial direction and frictionally engaged with each other. It has become.

  As shown in FIG. 1 (b), the cam mechanism 15 is spline-fitted to the outer periphery of the inner shaft 4 so as to be integrally rotatable with the inner shaft 4 and movable in the axial direction. A pilot cam 19 rotatably supported on the inner shaft 4 and a cam follower 20 interposed between the pilot cam 19 and the main cam 18 are provided. The main cam 18 as the first cam member and the pilot cam 19 as the second cam member are both formed in an annular shape. The main cam 18 is disposed on the main clutch 13 side, and the pilot cam 19 is disposed on the rear housing 6 side. The main cam 18 is spline-fitted to the pilot clutch 14 side of the spline groove of the inner shaft 4 to which the inner clutch plate 17 is fitted. The pilot cam 19 is in contact with a needle bearing 21 provided between the pilot cam 19 and the rear cam 6, and is supported so as to be relatively rotatable with a predetermined distance from the rear housing 6.

  A plurality of first cam grooves 23 are formed on the surface 22 of the main cam 18 facing the pilot cam 19. A plurality of second cam grooves 25 are formed on the surface 24 of the main cam 18 facing the pilot cam 19. The first cam groove 23 has the deepest portion 26 with the deepest axial depth, and the first cam groove from the deepest portion 26 when seen through from one axial side (rear housing 6 side). The forward cam portion 28a is formed on one side of the circumferential direction 23 and becomes shallow along the longitudinal direction with a predetermined gradient (8 ° in this embodiment), and the other side in the circumferential direction from the deepest portion 26. And a reverse cam portion 28b (see FIG. 2) whose depth decreases along the longitudinal direction with a predetermined gradient. Further, the second cam groove 25 has a deepest portion 27 having the deepest axial depth and a circumferential direction of the second cam groove 25 from the deepest portion 27 when viewed from one side in the axial direction. A forward cam portion 29a having a predetermined gradient along the longitudinal direction and a depth shallower with a predetermined gradient, and formed on one side in the circumferential direction from the deepest portion 27, with a predetermined depth along the longitudinal direction. It is comprised from the reverse direction cam part 29b (refer FIG. 2) which becomes shallow with a gradient. In the present embodiment, the first and second cam grooves 23 and 25 have a substantially U-shaped cross section in the short direction, and the cam follower 20 can be rolled. The cam follower 20 is sandwiched between the main cam 18 and the pilot cam 19 while being disposed in the first and second cam grooves 23 and 25 facing each other. Accordingly, in the cam mechanism 15, the main cam 18 and the pilot cam 19 rotate relative to each other, whereby the cam follower 20 rides on the forward cam portions 28 a and 29 a or the reverse cam portions 28 b and 29 b, and the main cam 18 and the pilot cam 19 The main cam 18 moves axially toward the main clutch 13 side.

  Further, as shown in FIG. 1A, like the main clutch 13, a plurality of outer clutch plates 30 and inner clutch plates 31 that are provided so as to be movable in the axial direction are alternately arranged in the pilot clutch 14. A multi-plate friction clutch is used. Specifically, each outer clutch plate 30 is splined to the inner periphery of the front housing 3 and the inner clutch plate 31 is splined to the outer periphery of the pilot cam 19, so that each outer clutch plate 30 can move in the axial direction and has a corresponding front. The housing 3 or the pilot cam 19 is provided so as to be rotatable together. The pilot clutch 14 connects the front housing 3 and the pilot cam 19 so that torque can be transmitted by the outer clutch plates 30 and the inner clutch plates 31 being pressed in the axial direction and frictionally engaged with each other. It has become.

  In other words, the pilot cam 19 with the cam follower 20 sandwiched between the main cam 18 and the main cam 18, that is, the inner shaft 4, rotates together with the front cam 3 and the pilot cam when the pilot clutch 14 is not in operation. 19, a rotational difference corresponding to the rotational difference between the front housing 3 and the inner shaft 4 is generated. The pilot clutch 14 is operated to connect the front housing 3 and the pilot cam 19 so that torque can be transmitted, so that the torque based on the rotational difference between the front housing 3 and the inner shaft 4 (pilot cam 19) is cammed. It is transmitted to the mechanism 15.

  That is, in the driving force transmission device 1, the torque based on the rotational difference between the front housing 3 and the inner shaft 4 is transmitted to the cam mechanism 15 by the operation of the pilot clutch 14, and the cam mechanism 15 is connected to the main cam 18 generated by the torque. Based on the rotation difference from the pilot cam 19, the main cam 18 is moved to the axial main clutch 13 side. That is, the cam mechanism 15 converts the torque based on the rotational difference between the front housing 3 and the inner shaft 4 transmitted through the pilot clutch 14 into an axial thrust and amplifies it. When the main cam 18 presses the main clutch 13, the main clutch 13 is operated, that is, the front housing 3 and the inner shaft 4 are connected so as to transmit torque.

  In the present embodiment, the pilot clutch 14 is configured as an electromagnetic clutch using the electromagnet 32 as a drive source. Specifically, the rear housing 6 is formed with an annular groove 33 that opens to the outside of the front housing 3 (on the side opposite to the front housing 3, the right side in FIG. 2), and the electromagnet 32 is disposed inside the annular groove 33. Is housed in. The rear housing 6 is provided with a cylindrical portion 6a extending axially from the inner peripheral portion thereof to the side opposite to the front housing 3, and the electromagnet 32 is supported by a ball bearing 34 provided on the cylindrical portion 6a. 6 (and the front housing 3) are rotatably supported.

  An annular armature 35 is slid in the cylinder of the front housing 3 in the axial direction at a position where the outer clutch plate 30 and the inner clutch plate 31 are sandwiched between the armature 35 and the rear housing 6. The spline is movably fitted. The pilot clutch 14 moves so that the armature 35 is attracted by the electromagnetic force of the electromagnet 32 and sandwiches the outer clutch plates 30 and the inner clutch plates 31 with the rear housing 6. The clutch plate 30 and the inner clutch plate 31 are frictionally engaged.

  As described above, the driving force transmission device 1 can control the operation of the pilot clutch 14 through the power supply to the electromagnet 32. The operation of the main clutch 13, that is, the torque that can be transmitted between the front housing 3 and the inner shaft 4 can be freely controlled through the operation of the pilot clutch 14.

  Next, the first and second cam grooves 23 and 25 formed on the opposed surfaces 22 and 24 of the main cam 18 and the pilot cam 19 will be described. 2A is a partial plan view of the main cam 18, and FIG. 2B is a cross-sectional view of the main cam 18 taken along the alternate long and short dash line in FIG. 2A, that is, along the longitudinal direction of the first cam groove 23. Indicates.

  The plurality of (six in this embodiment) first cam grooves 23 are formed such that their forward cam portions 28a are inclined at a first predetermined angle with respect to the circumferential direction, and their reverse cam portions 28b are circumferential. Inclined by a second predetermined angle with respect to the direction. The plurality of (six in the present embodiment) second cam grooves 25 have a first predetermined angle with respect to the circumferential direction when the forward cam portion 29a is seen through from one side in the axial direction. The reverse cam portion 29b is formed to be inclined at a fourth predetermined angle different from the second predetermined angle with respect to the circumferential direction. More specifically, as shown in FIGS. 2A and 2B, the straight forward cam portion 28a rotates clockwise from the deepest portion 26 in the circumferential direction (when viewed from the axial rear housing 6 side). The straight reverse cam portion 28b is formed to be inclined at the second predetermined angle from the deepest portion 26 to the other side in the circumferential direction (left rotation direction). Yes. In FIG. 2A, the bottom portion of the first cam groove 23 in the short direction is indicated by a one-dot chain line. In the present embodiment, each forward cam portion 28a is inclined at a first predetermined angle with respect to the circumferential direction so as to be directed radially inward, and each reverse cam portion 28b is directed radially inward. The deepest portion 26 is positioned at the outermost radial direction in the first cam groove 23 by being inclined at the second predetermined angle with respect to the circumferential direction. That is, each first cam groove 23 is formed in a substantially V shape. The first cam grooves 23 are formed so as not to overlap a plurality of rows (two or more rows) along the radial direction. The first cam grooves 23 are formed at predetermined intervals along the circumferential direction, and are provided within a predetermined angle range (60 ° in the present embodiment) on the facing surface 22.

  The second cam groove 25 is formed on the facing surface 24 in the same shape as the first cam groove 23. That is, when viewed through from one side in the axial direction, the forward cam portion 29a is formed on the other side in the circumferential direction from the deepest portion 27, and the second cam portion 29a is formed in the circumferential direction so as to go radially inward. It is formed to be inclined at a third predetermined angle (in this embodiment, the same angle as the second predetermined angle) different from the first predetermined angle. In addition, the reverse cam portion 29b is formed on one side in the circumferential direction from the deepest portion 27, and the reverse cam portions 29b are different from the second predetermined angle with respect to the circumferential direction so as to be directed radially inward. Each second cam groove 25 is formed in a substantially V shape by being inclined at 4 predetermined angles (in this embodiment, the same angle as the first predetermined angle). Accordingly, the main cam 18 and the pilot cam 19 are in the neutral position (the position where the deepest portion 26 of the first cam groove 23 and the deepest portion 27 of the second cam groove 25 are opposed to each other) and the forward cam portion 28a. The direction cam part 29a intersects and opposes, and the reverse cam part 28b and the reverse cam part 29b intersect and oppose each other.

Next, the operation of the cam mechanism 15 will be described.
As shown in FIG. 3A, when the main cam 18 and the pilot cam 19 are in the neutral position, the cam follower 20 is located at the deepest portions 26 and 27 of the first and second cam grooves 23 and 25. As shown in FIG. 3B, the main cam 18 and the pilot cam 19 are closest to each other, and no axial thrust is generated. Next, as shown in FIG. 4A, when the main cam 18 rotates relative to the pilot cam 19 in the circumferential direction, the forward cam portions 28a and 29a are inclined at different angles with respect to the circumferential direction. Therefore, the first cam grooves 23 and the second cam grooves 25 face each other in a crossed state. At this time, the cam follower 20 rolls as the main cam 18 and the pilot cam 19 rotate relative to each other, and moves from the deepest portions 26 and 27 to a position where the first cam groove 23 and the second cam groove 25 intersect. It is pinched. As shown in FIG. 4B, the cam follower 20 is located in each of the forward cam portions 28a and 29a of the first and second cam grooves 23 and 25, and the main cam 18 and the pilot cam 19 are separated from each other. Axial thrust is generated. When the main cam 18 rotates relative to the pilot cam 19 in one circumferential direction, the cam follower 20 is positioned in each of the reverse cam portions 28b and 29b of the first and second cam grooves 23 and 25, and The pilot cam 19 is separated and axial thrust is generated.

  When the main cam 18 and the pilot cam 19 are relatively rotated, the longitudinal direction of the first cam groove 23 and the longitudinal direction of the second cam groove 25 are different from each other. It cannot move from the position where the second cam groove 25 intersects (see FIG. 4B). Therefore, as in the conventional case, the cam followers 20 are prevented from moving relative to each other with the first cam member and the second cam member rotating relative to each other without using a retainer that holds a plurality of cam followers at a predetermined interval. In addition, all the cam followers 20 are prevented from moving in the same direction at the same time. As a result, for example, it is possible to prevent the thrust from being generated in the neutral position, and it is possible to generate the thrust accurately with a simple configuration.

  Further, when the vehicle is traveling, the driving force transmission device 1 rotates due to the input of the driving force, so that centrifugal force acts on the cam mechanism 15 and the cam follower 20 tends to move radially outward. Since the deepest portion 26 of the first and second cam grooves 23 and 25 is formed so as to be the outermost radial direction, the cam follower 20 is the deepest portion of the first and second cam grooves 23 and 25 while the vehicle is traveling. Try to move to 26,27. Therefore, when the main cam 18 and the pilot cam 19 are in the neutral position, the cam follower 20 settles at the deepest portion 26, and for example, the generation of thrust when the main cam 18 and the pilot cam 19 are in the neutral position is prevented.

As described above, according to the present embodiment, the following effects can be obtained.
(1) The cam mechanism 15 is sandwiched between a main cam 18 and a pilot cam 19 that are coaxially rotatable relative to each other, and a plurality of first and second cam grooves 23 and 25 formed respectively on the opposing surfaces 22 and 24 thereof. The cam follower 20 is configured. The first cam groove 23 is formed with the forward cam portion 28a inclined at a first predetermined angle with respect to the circumferential direction, and the reverse cam portion 28b is inclined at the second predetermined angle with respect to the circumferential direction. Formed. Further, when the second cam groove 25 is seen through from one side in the axial direction, the forward cam portion 29a is inclined at a third predetermined angle different from the first predetermined angle with respect to the circumferential direction. In addition, the reverse cam portion 29b is formed to be inclined at a fourth predetermined angle different from the second predetermined angle with respect to the circumferential direction. By configuring the cam mechanism 15 in this way, the first and second cam grooves 23 and 25 intersect and face each other in a state where the main cam 18 and the pilot cam 19 are relatively rotated, and the first cam groove 23 and the second cam groove 23 are opposed to each other. The cam follower 20 is clamped at a position where the cam groove 25 intersects. Therefore, when the main cam 18 and the pilot cam 19 are relatively rotated, the longitudinal direction of the first cam groove 23 and the longitudinal direction of the second cam groove 25 face different directions, and the cam follower 20 cannot move from the intersecting position. Therefore, as in the conventional case, the cam followers 20 are prevented from relatively moving while the main cam 18 and the pilot cam 19 are relatively rotated without using a retainer that holds the plurality of cam followers 20 at a predetermined interval. All cam followers 20 are prevented from moving in the same direction at the same time. As a result, for example, it is possible to prevent the thrust from being generated in the neutral position, and the thrust can be generated with high accuracy according to the relative rotation amount between the main cam 18 and the pilot cam 19 with a simple configuration. Moreover, since it is not necessary to use a retainer, the number of parts and the number of work steps can be reduced. Furthermore, since the forward cam portions 28a and 29a and the backward cam portions 28b and 29b are formed in the first and second cam grooves 23 and 25, the main cam 18 and the pilot cam 19 An axial thrust can be generated regardless of the direction of relative rotation.

  (2) Since the first cam grooves 23 are formed so as not to overlap a plurality of rows along the radial direction, the diameter of the main cam 18 is larger than when the first cam grooves 23 are formed in a plurality of rows along the radial direction. The direction can be reduced in size. Similarly, the pilot cam 19 can be reduced in size in the radial direction.

  (3) Since the forward cam portions 28a and 29a and the reverse cam portions 28b and 29b are formed in a straight line, for example, the forward cam portions 28a and 29a and the reverse cam portions 28b and 29b are curved. The first and second cam grooves 23 and 25 can be easily formed as compared with the case where the first and second cam grooves 23 and 25 are formed in a complicated shape.

  (4) The first and second cam grooves 23, 25 are formed such that the deepest portions 26, 27 are on the outermost radial direction. Therefore, when the driving force is input to the driving force transmission device 1 and the centrifugal force acts on the cam mechanism 15 in a state where the main cam 18 and the pilot cam 19 are in the neutral position, the cam follower 20 settles on the deepest portion 26 and The generation of thrust that does not occur can be prevented.

  (5) Since the first and second cam grooves 23 and 25 are formed at predetermined intervals along the circumferential direction, the main cam 18 can be moved in parallel, and the main cam 18 and the pilot cam 19 can be separated.

  (6) Since the thrust can be generated with high accuracy according to the relative rotation amount between the main cam 18 and the pilot cam 19 by the cam mechanism 15, for example, transmission of torque in an unintended state is prevented, and transmission torque is prevented. Can be accurately controlled.

In addition, you may implement this embodiment in the following aspects.
In the present embodiment, each of the forward cam portions 28a and 29a and each of the reverse cam portions 28b and 29b is inclined with respect to the circumferential direction at an angle as shown in FIG. The first and second cam grooves 23 and 25 may be formed by inclining the forward cam portions 41a and 42a and the reverse cam portions 41b and 42b with respect to the circumferential direction at an angle as shown in FIG. Good.

  In the present embodiment, the forward cam portions 28a and 29a and the reverse cam portions 28b and 29b are formed in a straight line, but the forward cam portions 28a and 29a and the reverse cam portions are not limited thereto. 28b and 29b may be formed in a curved shape.

  In the present embodiment, the first and second cam grooves 23 and 25 are formed on the opposing surfaces 22 and 24 so as not to overlap with each other in the radial direction. The cam grooves 23 and 25 may be formed in rows so as to overlap with each other along the radial direction.

  In the present embodiment, the deepest portions 26 and 27 of the first and second cam grooves 23 and 25 are positioned on the outermost radial direction. However, the present invention is not limited to this, and for example, the deepest portions 26 and 27 are the first and second cam grooves The second cam grooves 23 and 25 may be positioned radially inward from the longitudinal ends of the second cam grooves 23 and 25. That is, for example, as shown in FIG. 5B, the first and second cam grooves 43 and 44 may be formed.

  In the present embodiment, the first and second cam grooves 23 and 25 have a substantially U-shaped cross section along the short direction. However, the present invention is not limited thereto, and the cam follower 20 can roll. For example, the cross section in the lateral direction may be V-shaped or U-shaped.

  In the present embodiment, the cam mechanism 15 is used for the driving force transmission device 1, but the present invention is not limited thereto, and relative rotation can be given to the first cam member and the second cam member, and axial thrust is generated. As long as the device needs to be used, it may be used for other devices.

(A) Schematic sectional drawing of a driving force transmission device, (b) A partially enlarged view of (a). (A) The partial top view of the main cam which shows the shape of a 1st cam groove, (b) The partial sectional view of the main cam along the longitudinal direction of a 1st cam groove. (A) The schematic diagram which shows the cam mechanism of the state which is not rotating relatively seen from the axial direction rear housing side, (b) The schematic diagram which shows the cross section along the longitudinal direction of the 2nd cam groove in the state of (a). (A) The schematic diagram which shows the cam mechanism of the state rotated relatively seen from the axial direction rear housing side, (b) The schematic diagram which shows the cross section along the longitudinal direction of the 2nd cam groove in the state of (a). (A), (b) The schematic diagram which shows the cam mechanism of the state which is another relative rotation seen from the axial direction rear housing side. (A)-(d) The schematic diagram which shows the cross section along the circumferential direction of the conventional cam mechanism.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Driving force transmission device, 3 ... Front housing, 4 ... Inner shaft, 13 ... Main clutch, 15 ... Cam mechanism, 18 ... Main cam, 19 ... Pilot cam, 20 ... Cam follower, 22, 24 ... Opposing surface, 23, 43 ... 1st cam groove, 25, 44 ... 2nd cam groove, 26, 27 ... Deepest part, 28a, 29a, 41a, 42a ... Forward direction cam part, 28b, 29b, 41b, 42b ... Reverse direction cam part.

Claims (5)

A first cam member and a second cam member that are coaxially rotatable relative to each other, and a plurality of first cam grooves and second cam grooves respectively formed on opposing surfaces of the first cam member and the second cam member. The first cam groove is formed at the deepest portion having the deepest axial depth and on one side in the circumferential direction from the deepest portion, and has a shallow depth along the longitudinal direction. And a reverse cam portion formed on the other side in the circumferential direction from the deepest portion and having a shallow depth along the longitudinal direction, and the second cam groove has an axial direction The deepest part having the deepest depth, the forward cam part formed on the other side in the circumferential direction from the deepest part, and the depth decreasing along the longitudinal direction, and the longitudinal part formed on the one side in the circumferential direction from the deepest part. A first cam member comprising a reverse cam portion having a shallow depth along the direction. In a cam mechanism for generating the axial thrust by the cam follower by a relative rotation between the second cam member rides on the forward cam portion or said backward cam portion,
The forward cam portion of the first cam groove is formed at a first predetermined angle with respect to the circumferential direction, and the reverse cam portion of the first cam groove is inclined at a second predetermined angle with respect to the circumferential direction. Formed,
The forward cam portion of the second cam groove is formed to be inclined at a third predetermined angle different from the first predetermined angle with respect to the circumferential direction, and the reverse cam portion of the second cam groove is circumferentially formed. A cam mechanism, wherein the cam mechanism is inclined at a fourth predetermined angle different from the second predetermined angle.   2. The cam mechanism according to claim 1, wherein each of the first and second cam grooves is formed so as not to overlap a plurality of rows along a radial direction.   The cam mechanism according to claim 1 or 2, wherein the forward cam portion and the reverse cam portion are linearly formed.   The cam mechanism according to any one of claims 1 to 3, wherein each of the first and second cam grooves is formed such that the deepest portion is the outermost in the radial direction.   A cylindrical first rotating member that is rotated by input of a driving force; a second rotating member that is coaxially rotatable with the first rotating member inside the first rotating member; and the first rotating member; A clutch mechanism that is arranged between the second rotating member and is pressed in the axial direction so as to connect the first rotating member and the second rotating member so as to transmit torque; the first rotating member; A driving force transmission device comprising: the cam mechanism according to any one of claims 1 to 4 that presses the clutch mechanism in an axial direction in accordance with relative rotation of two rotating members.

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