Cam clutch

Abstract

To provide a cam clutch that has a simple structure and can be easily switched between operation modes with a small force.SOLUTION: A cam clutch comprises: first energization means 150 for energizing a plurality of cams 136 arranged between an inner ring 110 and an outer ring 120 which are relatively rotatably and coaxially arranged so that the cams are rotated in an engagement direction; and second energization means 155 for energizing the cams so as to be rotated in a disengaging direction with an energization force of a different magnitude from the energization force applied by the first energization means 150. The cam clutch is configured to be switchable between operation modes by changing the energization force applied by one of the first energization means 150 and the second energization means 155 that has a greater energization force on the same cam to be relatively smaller than the energization force applied by the other energization means by switching means 170.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a cam clutch. [Background technology]

[0002] Some types of clutches that control the transmission and interruption of rotational force are configured with an inner ring and an outer ring, a number of cams as engaging elements arranged between the inner ring and the outer ring, and a biasing means for biasing the cams in the meshing direction.For example, some are also known that are configured with a switching means that is configured to change the operating mode of the clutch by forcibly tilting the cam.

[0003] For example, in Patent Document 1 or Patent Document 2, forward rotation sprags and reverse rotation sprags as engaging elements are arranged between an inner ring and an outer ring while being biased in the meshing direction by a biasing means, and the forward rotation sprags and reverse rotation sprags can be tilted in the meshing release direction by moving a switching means in the axial direction. In these two-way clutches, when torque is input to the inner or outer ring, one of the forward and reverse sprags becomes a wedge and bites into the inner or outer ring, enabling torque transmission. On the other hand, by moving the switching means axially to tilt the forward and reverse sprags in the disengagement direction against the biasing force of the biasing means, it is possible to allow them to rotate freely in both forward and reverse directions. Furthermore, by providing a switching means in a one-way clutch, it is possible to realize a free mode that permits relative rotation of the inner and outer rings in both forward and reverse directions. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 6-017851 [Patent Document 2] JP 2008-121867 A Summary of the Invention [Problem to be solved by the invention]

[0005] In a clutch equipped with a switching means, the sprags are firmly supported by the torque received from the inner and outer rings during torque transmission, and therefore an extremely large force is required for the switching means to press the sprags circumferentially and tilt them in the disengagement direction, and operating the switching means during torque transmission may result in damage to the sprags and / or the switching means.

[0006] In particular, in a two-way clutch that can switch between driving and idling in both the forward and reverse directions, when torque is applied to the inner or outer ring, elastic deformation occurs in the sprags and the inner and outer rings, respectively. As a result, a rotational angle difference (windup) occurs between the inner and outer rings, and when the load is removed, the windup returns to zero. During torque transmission when one of the forward and reverse sprags meshes with the inner and outer rings, the other sprag continues to slide and contact with the outer and inner rings, and maintains a state of meshing standby. Therefore, when the torque is released, one of the sprags tilts in the meshing release direction and transitions to an idling state, but at this time, before the meshing of one sprag is released, the other sprag tilts in the meshing direction and begins to mesh with the outer and inner rings, which may result in "meshing" where all the cams mesh simultaneously. As described above, in the two-way clutch, because meshing occurs due to wind-up, even if the rotation of the inner or outer ring is stopped and the torque is removed, all of the sprags are meshed with high surface pressure, so a large force is required to press the sprags circumferentially using the switching means to incline them in the meshing release direction.

[0007] The present invention has been made in light of the above circumstances, and has an object to provide a cam clutch that has a simple structure and is capable of easily switching operation modes with little force. [Means for solving the problem]

[0008] The present invention solves the above-mentioned problems by providing a cam clutch comprising an inner ring and an outer ring arranged coaxially and rotatably relative to each other, a plurality of cams arranged between the inner ring and the outer ring, a first biasing means for biasing the cam to rotate in an engagement direction, and a switching means configured to forcibly rotate the cam to switch operating modes, the cam clutch further comprising a second biasing means for biasing the cam to rotate in a disengagement direction with a biasing force different in magnitude from the biasing force applied by the first biasing means, the switching means having a cam posture changing section configured to be able to change the biasing force applied by one of the first and second biasing means, which has a larger biasing force on the same cam, to be smaller than the biasing force applied by the other biasing means. Effect of the Invention

[0009] According to the invention of claim 1, it is possible to switch between the locked mode and the free mode by changing the balance between the biasing force in the meshing direction by the first biasing means and the biasing force in the release direction by the second biasing means, which act on the same cam, rather than directly pressing the cam to tilt it. Therefore, the force required to switch the operation mode only needs to be large enough to elastically deform the biasing means, and the operation mode can be easily switched with a small force using a simple structure. In addition, it is possible to easily operate the switching means even during torque transmission without stopping the rotation of the inner and outer rings when switching the operation mode.

[0010] According to the invention as defined in claim 2, there is no variation in the rotational operation of each of the multiple cams, and stable operation can be achieved. According to the invention of claim 3, by linking the rotational movements of the first cam and the second cam, which have different meshing directions, it is possible to rotate either one of the first cam and the second cam in the meshing direction in conjunction with the rotation of the other cam in the meshing release direction, so that when one cam is meshed with the inner ring and the outer ring, the other cam can be maintained apart from the inner ring or the outer ring. This makes it possible to reliably prevent meshing from occurring.

[0011] According to the invention of claims 4 to 6, by changing the biasing force of the first biasing means, the biasing force of the second biasing means rotates the cam in the disengagement direction and away from the inner or outer ring, making it possible to operate the switching means more easily with less force.

[0012] According to the invention of claim 7, at least one of the first biasing means and the second biasing means is common to each of the multiple cams, making it possible to reduce the number of parts and to avoid variations in the behavior of the cams.

[0013] According to the invention of claim 8, by selectively rotating either one or both of the first cam and the second cam, it is possible to switch between four operating modes: a bidirectional locked mode in which torque can be transmitted in both the forward and reverse directions, a forward direction locked mode in which torque can be transmitted only in the forward direction, a reverse direction locked mode in which torque can be transmitted only in the reverse direction, and a bidirectional free mode in which the motor rotates freely in both the forward and reverse directions. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is an exploded perspective view showing a configuration of a cam clutch according to a first embodiment of the present invention. [Diagram 2] 2 is a cross-sectional perspective view of the cam clutch shown in FIG. 1 in an assembled state, taken along a plane including a rotation axis. [Diagram 3] FIG. 4 is an exploded perspective view showing the configuration of a cam mechanism. [Figure 4] 3 is a plan view showing the cam clutch shown in FIG. 2 with a portion of the configuration thereof omitted, as viewed from one axial end side. FIG. [Diagram 5] 1A and 1B are diagrams showing the configuration of a cam, in which (a) is a plan view seen from one axial end side, and (b) is a side view. [Figure 6] 2 is a side view showing a state in which the operation mode of the cam clutch shown in FIG. 1 is switched from a bidirectional free mode to a bidirectional locked mode. FIG. [Figure 7] 2 is a diagram illustrating a schematic state when the operation mode of the cam clutch illustrated in FIG. 1 is in a bidirectional free mode. FIG. [Figure 8A] 2 is a diagram illustrating a schematic state when the operation mode of the cam clutch illustrated in FIG. 1 is in a bidirectional lock mode. FIG. [Figure 8B] 2 is a diagram illustrating a schematic state when the inner ring is rotated in the forward direction when the operating mode of the dog clutch illustrated in FIG. 1 is in a bidirectional lock mode. FIG. [Figure 9] FIG. 6 is a cross-sectional perspective view cut along a plane including a rotation axis, showing a configuration of a cam mechanism in a cam clutch according to a second embodiment of the present invention. [Figure 10A] FIG. 11 is a schematic diagram showing, with some parts omitted, the configuration of a cam clutch according to a second embodiment of the present invention, and is a plan view seen from one axial end side when the operation mode of the cam clutch is in a bidirectional lock mode. [Figure 10B] FIG. 11 is a plan view illustrating a state in which the operation mode of the cam clutch according to the second embodiment of the present invention is in a bidirectional free mode. [Figure 11] FIG. 11 is a perspective view showing the configuration of a second biasing means in a cam clutch according to a third embodiment of the present invention, together with some cams. [Figure 12A] FIG. 11 is a schematic diagram showing, with some parts omitted, the configuration of a cam clutch according to a third embodiment of the present invention, and is a plan view seen from one axial end side when the operation mode of the cam clutch is in a bidirectional free mode. [Figure 12B] FIG. 11 is a plan view illustrating a meshing standby state when the operation mode of the cam clutch according to the third embodiment of the present invention is in a bidirectional lock mode. [Figure 13] FIG. 11 is a perspective view showing the configuration of a cam clutch according to a fourth embodiment of the present invention, with a part cut away. [Figure 14A] 14 is a side view showing a state when the operation mode of the cam clutch shown in FIG. 13 is in a bidirectional free mode. FIG. [Figure 14B] 14 is a plan view showing a schematic state of the cam clutch shown in FIG. 13 when the operation mode is in a bidirectional free mode. FIG. [Figure 15A] 14 is a side view showing a state when the operation mode of the cam clutch shown in FIG. 13 is in a forward rotation direction lock mode. FIG. [Figure 15B] 14 is a plan view showing a meshing standby state when the operation mode of the cam clutch shown in FIG. 13 is in a forward rotation direction lock mode. FIG. [Figure 16A] 14 is a side view showing a state when the operation mode of the cam clutch shown in FIG. 13 is in a reverse direction lock mode. FIG. [Figure 16B] 14 is a plan view showing a meshing standby state when the operation mode of the cam clutch shown in FIG. 13 is in a reverse direction lock mode. FIG. [Figure 17A] 14 is a side view showing a state when the operation mode of the cam clutch shown in FIG. 13 is in a bidirectional lock mode. FIG. [Figure 17B] 14 is a diagram showing a schematic diagram of an engagement standby state when the operation mode of the cam clutch shown in FIG. 13 is in a bidirectional lock mode. FIG. [Figure 18] FIG. 13 is a perspective view showing the configuration of a cam clutch according to a fifth embodiment of the present invention, with a portion cut away. [Figure 19A] 19 is a diagram showing a portion of a cross section taken along a plane including the rotation axis, illustrating a state when the operating mode of the cam clutch shown in FIG. 18 is in a locked mode in which torque is transmitted in both directions between the outer ring and the first inner ring. [Figure 19B] 19 is a diagram showing a part of a cross section cut along a plane including a rotation axis, illustrating a state when the operation mode of the cam clutch shown in FIG. 18 is in a bidirectional free mode. FIG. [Figure 19C]19 is a diagram showing a portion of a cross section taken along a plane including the rotation axis, illustrating a state when the operating mode of the cam clutch shown in FIG. 18 is in a locked mode in which torque can be transmitted in both directions between the outer ring and the second inner ring. [Figure 20] FIG. 11 is a plan view showing another example of a cam clutch according to the present invention, as viewed from one axial end side. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] [First embodiment] As shown in FIG. 1, the cam clutch 100 according to the first embodiment of the present invention includes an inner ring 110, an outer ring 120, a cam mechanism 130 that transmits and cuts off torque between the inner ring 110 and the outer ring 120, and a switching means 170 configured to be able to switch the operating mode of the cam clutch 100. As shown in FIG. 2, in an assembled state of the cam clutch 100, the inner ring 110 and the outer ring 120 are disposed on the same rotation axis so as to be relatively rotatable, and the cam mechanism 130 is disposed between the inner ring 110 and the outer ring 120.

[0016] As shown in FIG. 3, the cam mechanism 130 includes a plurality of cams 136, a cage ring 140 that holds each of the plurality of cams 136, a first biasing means 150 that biases each of the plurality of cams 136 to rotate in the meshing direction, and a second biasing means 155 that biases each of the plurality of cams 136 to rotate in the disengagement direction with a biasing force of a different magnitude than the biasing force applied by the first biasing means 150.

[0017] As shown in FIG. 4, the multiple cams 136 include first cams 136a and second cams 136b whose meshing directions with respect to the inner ring 110 and the outer ring 120 are different from each other. In this embodiment, adjacent first cams 136a and second cams 136b form cam pairs 135 and are arranged in multiple pairs at a predetermined interval in the circumferential direction on the same circumference. The arrangement of the first cams 136a and the second cams 136b in the cam mechanism 130 is not particularly limited, but by arranging the first cams 136a and the second cams 136b so that they are alternately arranged, it is possible to rotate the first cams 136a and the second cams 136b simultaneously by a common switching means, and it is possible to avoid the structure of the cam clutch 100 becoming complicated and large-sized. In addition, the first cams 136a and the second cams 136b do not need to be arranged alternately on the same circumference, and the number of the first cams 136a and the second cams 136b may be the same or different.

[0018] The first cam 136a is configured to frictionally engage with the inner ring 110 and the outer ring 120 when the inner ring 110 is rotated in the forward direction (clockwise in Figure 4) or the outer ring 120 is rotated in the reverse direction (counterclockwise in Figure 4), and is configured to tilt in a direction such that it disengages from the inner ring 110 and becomes non-contact when the inner ring 110 is rotated in the reverse direction or the outer ring 120 is rotated in the forward direction. Therefore, the second cam 136b is configured to frictionally engage with the inner ring 110 and the outer ring 120 when the inner ring 110 is rotated in the reverse direction or the outer ring 120 is rotated in the forward direction, and to tilt in a direction such that it disengages from the inner ring 110 and becomes non-contact when the inner ring 110 is rotated in the forward direction or the outer ring 120 is rotated in the reverse direction.

[0019] In this embodiment, the first cam 136a and the second cam 136b have, for example, the same outer shape, and the first cam 136a is turned upside down and used as the second cam 136b. Hereinafter, the first cam 136a and the second cam 136b may be simply referred to as cam 136, except when they are particularly distinguished from each other. Note that the first cam 136a and the second cam 136b may have different outer shapes, but by having the same outer shape, it is possible to reduce the number of parts.

[0020] As shown in FIGS. 5(a) and 5(b), the cam 136 in this embodiment has a rotation shaft portion 137 provided so as to protrude axially outward on each of both end faces extending along a plane perpendicular to the center of rotation. A notch 139a is formed in a side surface portion continuing to the inner ring side engagement surface on the mesh release direction side (clockwise direction in FIG. 5(a)) of the contact point of cam 136 with inner ring 110. Also, a step 139b configured to be engageable with a connecting portion 156b of a torsion spring constituting second biasing means 155 described later is formed in a side surface portion continuing to the inner ring side engagement surface on the meshing direction side (counterclockwise direction in FIG. 5(a)) of the contact point.

[0021] As shown in FIG. 3, the cage ring 140 is composed of a pair of annular plate members 141 and rod-shaped spacer members 145 that connect the annular plate members 141 at a predetermined interval in the axial direction. Each annular plate member 141 is formed with a holding hole 142 that rotatably holds the rotary shaft portion 137 of the cam 136 and an insertion hole 143 through which a cam position changing portion 171 of the switching means 170 is inserted. The spacer members 145 are arranged at predetermined intervals in the circumferential direction on the same circumference so as to be positioned between the first cam 136a and the second cam 136b of each of the plurality of cam pairs 135.

[0022] In this embodiment, the first biasing means 150 is formed of a leaf spring, and is provided corresponding to each cam 136. Specifically, as also shown in Fig. 5(a), the first biasing means 150 is disposed in a position in which the bent portion is located at the other axial end side in the notch portion 139a of the cam 136, and one piece-like portion continuous with the bent portion is fixed to the cam 136 as a fixed piece. The other piece-like portion continuous with the bent portion is formed as a movable piece, and is adapted to come into contact with a cam position changing portion 171 of the switching means 170.

[0023] The second biasing means 155 is formed of a torsion spring and is provided corresponding to each cam 136. Specifically, as shown in FIG. 5(b), the torsion spring has two coil-shaped winding parts 156a and a connecting part 156b that is configured to extend linearly in the axial direction and connects one end of each of the winding parts 156a to each other, and the winding parts 156a are fitted onto the rotary shaft part 137 at one end side and the other end side of the cam 136 in the axial direction, and the connecting part 156b is engaged with the step part 139b of the cam 136 to be attached. The other end of each winding part 156a is supported by a second biasing means support part 144 formed on the annular plate-shaped member 141 of the cage ring 140 as shown in FIG. 4. With this configuration, it is possible to avoid contact with the inner ring 110 when the cam 136 is lifted up.

[0024] The switching means 170 is provided so as to be movable in the axial direction between a first fixed position and a second fixed position which is located on one axial end side of the first fixed position. As shown in Figures 1 and 2, the switching means 170 is composed of a plurality of columnar cam position-changing portions 171 arranged between the inner ring 110 and the outer ring 120 and formed to extend in the axial direction, and a pair of annular plate-shaped fixing members 175 fixed to each of both end faces of each cam position-changing portion 171, and is arranged in a state where the cam position-changing portion 171 is inserted into the insertion hole 143 of the cage ring 140 so that it is positioned between adjacent cam pairs 135 and is axially movably inserted therein.

[0025] The cam posture change portion 171 is configured so that its cross-sectional shape changes in the axial direction, and thereby it is possible to change the biasing force of one of the first biasing means 150 and the second biasing means 155, whichever has a larger biasing force on the same cam 136, so that it becomes relatively smaller than the biasing force of the other biasing means.

[0026] In this embodiment, the cam position changing portion 171 is configured so that the biasing force of the first biasing means 150 against the cam 136 can be changed by axial movement of the switching means 170. Specifically, by axially moving the switching means 170 from a first fixed position to a second fixed position at one axial end side, the first biasing means 150 can be changed to a state in which it can be biased with a biasing force larger than that of the second biasing means 155, in other words, the biasing force of the second biasing means 155 can be changed to be smaller than that of the first biasing means 150. 1 and 2, the cam position changer 171 has a rectangular column-shaped biasing force imparting portion 172, a biasing force changing portion 173 connected to one end of the biasing force imparting portion 172, and a rectangular column-shaped biasing force release portion 174 connected to one end of the biasing force changing portion 173 and having a smaller radial dimension than the biasing force imparting portion 172. The biasing force changing portion 173 is formed such that its radially inner surface extends at an angle radially outward toward one axial end.

[0027] The cam clutch 100 according to this embodiment is equipped with a cam interlocking member 160 that transmits the rotation of one of the first cam 136a and the second cam 136b in the cam pair 135 to the other cam, thereby rotating the first cam 136a and the second cam 136b in conjunction with each other. As shown in FIG. 3, the cam interlocking member 160 has a circular base portion 161 having the same outer diameter dimension as the circular plate member 141 in the cage ring 140, and one end face of the base portion 161 has claw portions 162 that are configured to extend circumferentially and protrude in the axial direction and are formed at predetermined intervals in the circumferential direction. As shown in Figure 4, the cam interlocking member 160 is fitted onto the spacer member 145 so that the claw portion 162 is positioned between adjacent pairs of cams 135, thereby restricting radial movement, and the other end face of the base portion 161 is abutted against the inner surface of the annular plate member 141 of the cage ring 140 at one end side and the other end side of the cam 136.

[0028] In the above-mentioned cam clutch 100, as shown by the dashed line in Fig. 6, when the switching means 170 is in the first fixed position, as shown in Fig. 7, the movable piece of the first biasing means 150 contacts the biasing force changing portion 173 of the cam position changing portion 171, and the biasing force of the first biasing means 150 is smaller than the biasing force of the second biasing means 155, or the biasing force of the first biasing means 150 is released. Therefore, both the first cam 136a and the second cam 136b are biased to rotate in the mesh release direction, and both the first cam 136a and the second cam 136b are in a non-contact state separated from the outer circumferential surface of the inner ring 110. Therefore, the operation mode of the cam clutch 100 is a bidirectional free mode that allows the inner ring 110 and the outer ring 120 to rotate relative to each other in both forward and reverse directions.

[0029] As shown by the solid line in FIG. 6, when the switching means 170 is moved from the first fixed position to the second fixed position at one end in the axial direction, the cam position changing portion 171 presses the first biasing means 150 in the compression direction as shown in FIG. 8A. As a result, the biasing force of the first biasing means 150 becomes greater than the biasing force of the second biasing means 155, and the first cam 136a and the second cam 136b are biased to rotate in the meshing direction. Therefore, the first cam 136a and the second cam 136b come into sliding contact with the inner ring 110 and the outer ring 120, and either the first cam 136a or the second cam 136b is immediately in a meshing standby state in which it can be engaged with the inner ring 110 and the outer ring 120. Therefore, the operation mode of the cam clutch 100 is switched to a bidirectional lock mode that prohibits the relative rotational movement of the inner ring 110 and the outer ring 120 in both forward and reverse directions.

[0030] For example, as shown in Fig. 8B, when the inner ring 110 is rotated in the normal direction (clockwise in Fig. 8B), the first cam 136a rotates in the meshing direction so as to frictionally engage with the inner ring 110 and the outer ring 120. The rotation of the first cam 136a presses the claw portion 162 of the cam interlocking member 160 in the circumferential direction, causing the cam interlocking member 160 to rotate. As a result, the claw portion 162 of the cam interlocking member 160 presses the second cam 136b so as to rotate in the meshing release direction. The same is true when the outer ring 120 is rotated in the reverse direction (counterclockwise in Fig. 8). On the other hand, when the inner ring 110 is rotated in the reverse direction or the outer ring 120 is rotated in the forward direction, the second cam 136b rotates in the meshing direction so as to frictionally engage with the inner ring 110 and the outer ring 120, and in conjunction with this, the first cam 136a rotates in the disengagement direction due to the action of the cam interlocking member 160.

[0031] As described above, according to the above-mentioned cam clutch 100, the cam 136 is not directly pressed to rotate, but the balance between the biasing force in the meshing direction by the first biasing means 150 and the biasing force in the disengagement direction by the second biasing means 155 acting on the same cam 136 is changed, so that the operation mode can be switched between the bidirectional free mode and the bidirectional locked mode. Therefore, the force required for switching the operation mode is only large enough to elastically deform the first biasing means 150, and the operation mode can be easily switched with a small force with a simple structure. In addition, the switching means 170 can be easily operated even during torque transmission without stopping the rotation of the inner ring 110 and the outer ring 120 when switching the operation mode. In particular, when switching from the bidirectional locked mode to the bidirectional free mode, the biasing force of the first biasing means 150 is reduced, so that the biasing force of the second biasing means 155 causes the cam 136 to rotate in the disengagement direction and move away from the inner wheel 110 or the outer wheel 120, making it possible to operate the switching means 170 more easily with less force.

[0032] Furthermore, as one of the first cam 136a and the second cam 136b rotates in the meshing direction, the other cam can be rotated in the disengagement direction by the action of the cam interlocking member 160, so that when one cam is meshed with the inner ring 110 and the outer ring 120, the other cam can be maintained apart from the inner ring 110 or the outer ring 120. This makes it possible to reliably prevent jamming from occurring.

[0033] In the above cam clutch 100 according to the first embodiment, the first urging means 150 and the second urging means 155 are provided corresponding to each of the multiple cams 136. However, the first urging means 150 may be an elastic body capable of urging the first cam 136a and the second cam 136b to rotate in the meshing direction, and the second urging means 155 may be an elastic body capable of urging the first cam 136a and the second cam 136b to rotate in the meshing release direction. For example, at least one of the first urging means 150 and the second urging means 155 may be configured as a common urging means for the first cam 136a and the second cam 136b.

[0034] [Second embodiment] The cam clutch of the second embodiment of the present invention has a similar configuration to the cam clutch 100 of the first embodiment, except that a garter spring common to the first cam 136a and the second cam 136b is used as the first biasing means 150 instead of the leaf spring in the cam clutch 100 of the first embodiment.

[0035] As shown in FIG. 9, a garter spring as a first biasing means 150 is mounted in a mounting groove 138 formed to extend in the circumferential direction on the outer ring side engagement surface of each of the first cam 136a and the second cam 136b.

[0036] Cam position changer 171 of switching means 170 in this embodiment is formed so that the radially outer surface of biasing force changer 173 extends at an inclination radially inward toward one end (see FIG. 10B).

[0037] In the cam clutch according to the second embodiment, for example, when the switching means 170 is in the first fixed position, as shown in Fig. 10A, the first biasing means 150 contacts the radially outer surface of the biasing force release portion 174 of the cam position changing portion 171, and the biasing force of the first biasing means 150 is greater than the biasing force of the second biasing means 155. Therefore, both the first cam 136a and the second cam 136b are biased to rotate in the meshing direction, and both the first cam 136a and the second cam 136b are in sliding contact with the inner ring 110 and the outer ring 120, and either one of the first cam 136a and the second cam 136b is in a meshing standby state in which it can immediately engage with the inner ring 110 and the outer ring 120. Therefore, the operation mode of the cam clutch is a bidirectional lock mode that prohibits the relative rotation of the inner ring 110 and the outer ring 120 in both forward and reverse directions.

[0038] When the switching means 170 is moved from the first fixed position to the second fixed position at one axial end side, the cam position changing portion 171 presses the first biasing means 150 in the radially expanding direction, as shown in Fig. 10B. As a result, the biasing force of the first biasing means 150 becomes smaller than the biasing force of the second biasing means 155, or the biasing force of the first biasing means 150 is released, and both the first cam 136a and the second cam 136b are biased to rotate in the mesh release direction. Therefore, the first cam 136a and the second cam 136b are separated from the outer circumferential surface of the inner ring 110 and are in a non-contact state, and therefore the operation mode of the cam clutch 100 is switched to a bidirectional free mode that allows the inner ring 110 and the outer ring 120 to rotate relative to each other in both forward and reverse directions.

[0039] [Third embodiment] The cam clutch of the third embodiment of the present invention has a similar configuration to the cam clutch 100 of the first embodiment, except that a ribbon-shaped leaf spring common to the first cam 136a and the second cam 136b is used as the second biasing means 155 instead of the torsion spring in the cam clutch 100 of the first embodiment.

[0040] As shown in FIG. 11, the ribbon-shaped leaf spring as the second biasing means 155 comprises a pair of annular portions 157 extending parallel to each other in the circumferential direction, and a plurality of connecting portions 158 connecting the annular portions 157 in the axial direction at predetermined intervals, and is arranged so that the connecting portions 158 are positioned between the first cam 136a and the second cam 136b constituting the cam pair 135. The connecting portion 158 has a first leaf spring portion 159a that is formed so as to be convex radially outward and that urges the first cam 136a to rotate in the disengagement direction, and a second leaf spring portion 159b that is formed so as to be convex radially outward and that urges the second cam 136b to rotate in the disengagement direction.

[0041] In the cam clutch according to the third embodiment, for example, when the switching means 170 is in the first fixed position, as shown in Fig. 12A, the movable piece of the first biasing means 150 contacts the biasing force changing portion 173 of the cam position changing portion 171, and the biasing force of the first biasing means 150 is smaller than the biasing force of the second biasing means 155, or the biasing force of the first biasing means 150 is released. Therefore, both the first cam 136a and the second cam 136b are biased to rotate in the mesh release direction, and both the first cam 136a and the second cam 136b are in a non-contact state separated from the outer circumferential surface of the inner ring 110. Therefore, the operation mode of the cam clutch 100 is a bidirectional free mode that allows the relative rotational movement of the inner ring 110 and the outer ring 120 in both forward and reverse directions.

[0042] When the switching means 170 is moved from the first fixed position to the second fixed position at one axial end side, the cam position changing portion 171 presses the first biasing means 150 in the compression direction, as shown in Fig. 12B. As a result, the biasing force of the first biasing means 150 becomes larger than the biasing force of the second biasing means 155, i.e., the biasing force of the second biasing means 155 becomes smaller relative to the biasing force of the first biasing means 150, and the first cam 136a and the second cam 136b are biased to rotate in the meshing direction. Therefore, the first cam 136a and the second cam 136b come into sliding contact with the inner ring 110 and the outer ring 120, and either the first cam 136a or the second cam 136b is immediately brought into a meshing standby state in which it can engage with the inner ring 110 and the outer ring 120. Therefore, the operation mode of the cam clutch 100 is switched to a bidirectional lock mode in which the relative rotational movement of the inner ring 110 and the outer ring 120 is prohibited in both the forward and reverse directions.

[0043] In the above second and third embodiments, either one of the first urging means 150 or the second urging means 155 is configured by a urging means common to each of the multiple cams 136. However, both the first urging means and the second urging means may be configured by a urging means common to each of the multiple cams 136. By having at least one of the first urging means and the second urging means common to each of the multiple cams 136, it is possible to reduce the number of parts and to prevent variations in the behavior of the cams 136.

[0044] The above has described the present invention as being applied to a two-way clutch, but the present invention may also be applied to a selectable clutch whose operating modes can be switched between four operating modes including a forward direction lock mode and / or a reverse direction lock mode that prohibits relative rotational movement of the inner and outer rings in either the forward or reverse direction.

[0045] [Fourth embodiment] As shown in FIG. 13, the cam clutch of the fourth embodiment of the present invention has a configuration similar to that of the cam clutch 100 of the first embodiment, except that it has a first switching means 170a that changes the biasing force of one of the first biasing means 150 and the second biasing means 155 applied to the first cam 136a, and a second switching means 170b that changes the biasing force of one of the first biasing means 150 and the second biasing means 155 applied to the second cam 136b.

[0046] The first switching means 170a and the second switching means 170b are provided so as to be movable in the axial direction independently of each other between a first fixed position and a second fixed position which is located on one axial end side of the first fixed position.

[0047] The first switching means 170a is composed of a plurality of columnar first cam position change portions 171a arranged between the inner ring 110 and the outer ring 120 and formed to extend in the axial direction, and a pair of approximately annular plate-shaped first fixing members 175a fixed to each of both end faces of each of the first cam position change portions 171a. The first fixing member 175a has an annular plate portion 176a and a plurality of inward protruding pieces 176b formed to protrude radially inward from the inner peripheral edge of the annular plate portion 176a. The inward protruding pieces 176b are formed to be lined up at predetermined intervals in the circumferential direction, and the first cam position changing portions 171a are fixed to the inward protruding pieces 176b to be lined up on the same circumference. The first cam position changing portion 171a has a configuration similar to that of the cam position changing portion 171 in the cam clutch 100 according to the first embodiment. That is, in this embodiment, the first cam position changing portion 171a is configured to change the first biasing means 150 to a state in which the first cam 136a can be biased with a biasing force larger than that of the second biasing means 155 by the axial movement of the first switching means 170a, in other words, to change the biasing force of the second biasing means 155 to be smaller than that of the first biasing means 150. The first cam position changing portion 171a is disposed in a state in which it is inserted into the insertion hole 143 of the cage ring 140 so as to be positioned between adjacent cam pairs 135 and is movable in the axial direction.

[0048] The second switching means 170b is composed of a plurality of columnar second cam position change portions 171b arranged between the inner ring 110 and the outer ring 120 and formed to extend in the axial direction, and a pair of approximately annular plate-shaped second fixing members 175b fixed to each of both end faces of each of the second cam position change portions 171b. The second fixed member 175b has an annular plate portion 177a having an outer diameter dimension that allows it to be fitted to the radially inner side of the first fixed member 175a, and a plurality of outwardly protruding pieces 177b formed to protrude radially outward from the outer periphery of the annular plate portion 177a so as to be fitted between the inwardly protruding pieces 176b of the first fixed member 175a via gaps. The outwardly protruding pieces 177b are formed to be aligned at predetermined intervals in the circumferential direction, and the second cam position changing portion 171b is fixed to each outwardly protruding piece 177b so as to be aligned on the same circumference as the first cam position changing portion 171a. In this embodiment, like the first cam position changing portion 171a, the second cam position changing portion 171b is configured to change the first biasing means 150 to a state in which it can bias the second cam 136b with a biasing force greater than that of the second biasing means 155 by axial movement of the second switching means 170b, in other words, to change the biasing force of the second biasing means 155 to be smaller than the biasing force of the first biasing means 150. The second cam position changing portion 171b is disposed in a state in which it is inserted into the insertion hole 143 of the cage ring 140 so as to be positioned between adjacent cam pairs 135 and is axially movably inserted therein.

[0049] In the cam clutch according to the fourth embodiment, when the first switching means 170a and the second switching means 170b are both in the first fixed position as shown in Fig. 14A, the movable piece of the first urging means 150 for the first cam 136a and the movable piece of the first urging means 150 for the second cam 136b contact the urging force changing portion 173 of the first cam position changing portion 171a and the urging force changing portion 173 of the second cam position changing portion 171b, respectively, as shown in Fig. 14B, and the urging force of the first urging means 150 is smaller than the urging force of the second urging means 155, or the urging force of the first urging means 150 is released. Therefore, both the first cam 136a and the second cam 136b are urged to rotate in the mesh release direction, and both the first cam 136a and the second cam 136b are in a non-contact state separated from the outer circumferential surface of the inner ring 110. Therefore, the operation mode of the cam clutch is a bidirectional free mode that allows relative rotational movement of the inner ring 110 and the outer ring 120 in both forward and reverse directions.

[0050] As shown in Fig. 15A, when only the first switching means 170a is moved from the first fixed position to the second fixed position at one axial end side, the first cam position changing portion 171a presses the first biasing means 150 against the first cam 136a in the compression direction as shown in Fig. 15B. As a result, the biasing force of the first biasing means 150 becomes larger than the biasing force of the second biasing means 155, i.e., the biasing force of the second biasing means 155 becomes smaller relative to the biasing force of the first biasing means 150, and the first cam 136a is biased to rotate in the meshing direction. Therefore, the first cam 136a comes into sliding contact with the inner ring 110 and the outer ring 120, and when the inner ring 110 is rotated in the forward direction (clockwise in FIG. 15B) or the outer ring 120 is rotated in the reverse direction (counterclockwise in FIG. 15B), the first cam 136a immediately enters an engagement standby state in which it can engage with the inner ring 110 and the outer ring 120. Therefore, the operation mode of the cam clutch is switched to a forward rotation direction lock mode that prohibits the relative rotational movement of the inner ring 110 and the outer ring 120 in the forward rotation direction.

[0051] On the other hand, as shown in Fig. 16A, when only the second switching means 170b is moved from the first fixed position to the second fixed position at one axial end side, the second cam position changing portion 171b presses the first biasing means 150 against the second cam 136b in the compression direction as shown in Fig. 16B. As a result, the biasing force of the first biasing means 150 becomes larger than the biasing force of the second biasing means 155, that is, the biasing force of the second biasing means 155 becomes smaller relative to the biasing force of the first biasing means 150, and the second cam 136b is biased to rotate in the meshing direction. Therefore, the second cam 136b comes into sliding contact with the inner ring 110 and the outer ring 120, and when the inner ring 110 is rotated in the reverse direction (counterclockwise in FIG. 16B) or the outer ring 120 is rotated in the forward direction (clockwise in FIG. 16B), the second cam 136b immediately enters an engagement standby state in which it can engage with the inner ring 110 and the outer ring 120. Therefore, the operation mode of the cam clutch is switched to a reverse direction lock mode that prohibits the relative rotational movement of the inner ring 110 and the outer ring 120 in the reverse direction.

[0052] 17A, when the first switching means 170a and the second switching means 170b are both moved from the first fixed position to the second fixed position at one end in the axial direction, the biasing force of the first biasing means 150 becomes larger than the biasing force of the second biasing means 155, i.e., the biasing force of the second biasing means 155 becomes smaller relative to the biasing force of the first biasing means 150, and the first cam 136a and the second cam 136b are biased to rotate in the meshing direction, as shown in FIG. 17B. Therefore, the first cam 136a and the second cam 136b come into sliding contact with the inner ring 110 and the outer ring 120, and either the first cam 136a or the second cam 136b is immediately in a meshing standby state in which it can be engaged with the inner ring 110 and the outer ring 120. Therefore, the operation mode of the cam clutch is switched to a bidirectional lock mode that prohibits the relative rotation of the inner ring 110 and the outer ring 120 in both forward and reverse directions.

[0053] As described above, with the cam clutch, by selectively rotating either or both of the first cam 136a and the second cam 136b, it is possible to switch between four operating modes: a bidirectional locked mode in which torque can be transmitted in both the forward and reverse directions, a forward direction locked mode in which torque can be transmitted only in the forward direction, a reverse direction locked mode in which torque can be transmitted only in the reverse direction, and a bidirectional free mode in which the clutch idles in both the forward and reverse directions.

[0054] [Fifth embodiment] As shown in FIG. 18, the cam clutch according to the fifth embodiment of the present invention has a first cam mechanism 131a and a second cam mechanism 131b, and is configured so that its operating mode can be switched between a bidirectional lock mode in which torque is transmitted between the inner and outer wheels by the first cam mechanism 131a, a bidirectional lock mode in which torque is transmitted between the inner and outer wheels by the second cam mechanism 131b, and a bidirectional free mode in which torque transmission is blocked in both the forward and reverse directions.

[0055] In the cam clutch of this embodiment, a first inner ring 110a and a second inner ring 110b having the same configuration are arranged side by side in the axial direction, and an outer ring 120 is arranged coaxially with the first inner ring 110a and the second inner ring 110b so as to be rotatable relative to the first inner ring 110a and the second inner ring 110b. A first cam mechanism 131a is arranged between the first inner ring 110a and the outer ring 120, and a second cam mechanism 131b is arranged between the second inner ring 110b and the outer ring 120. Although not shown in the figure, a first outer ring and a second outer ring having the same configuration may be arranged side by side in the axial direction, and an inner ring may be arranged coaxially with the first outer ring and the second outer ring so as to be rotatable relative to the first outer ring and the second outer ring, and a first cam mechanism and a second cam mechanism may be arranged between the inner ring and the first outer ring and between the inner ring and the second outer ring, respectively.

[0056] The first cam mechanism 131a and the second cam mechanism 131b have the same configuration as the cam mechanism 130 in the cam clutch 100 according to the first embodiment, and as shown in FIG. 19A, the first cam mechanism 131a and the second cam mechanism 131b are arranged in such a manner that the leaf spring serving as the first biasing means 150 is convex toward the axially outward side.

[0057] The cam position changer 171 of the switching means 170 in this embodiment has a one-end biasing force imparting portion 172a, a first biasing force changer 173a connected to the other axial end of the one-end biasing force imparting portion 172a, a biasing force releaser 174 connected to the other axial end of the first biasing force changer 173a, a second biasing force changer 173b connected to the other axial end of the biasing force releaser 174, and an other-end biasing force imparting portion 172b connected to the other axial end of the second biasing force changer 173b. The one-end biasing force imparting portion 172a and the other-end biasing force imparting portion 172b are prismatic and have the same radial dimension as each other. The biasing force releaser 174 is prismatic and is configured to have a smaller radial dimension than the one-end biasing force imparting portion 172a and the other-end biasing force imparting portion 172b. The first biasing force changer 173a is configured so that its radially inner surface extends at an incline radially outward toward the other axial end. The second biasing force changer 173b is configured so that its radially inner surface extends at an incline radially inward toward the other axial end. Reference numeral 178 in Fig. 19A denotes a cylindrical extension portion for fixing the cam position changer 171 to a fixing member 175 on one axial end side.

[0058] In the cam clutch according to the fifth embodiment, for example, when the switching means 170 is in the first fixed position, as shown in Fig. 19A, the first biasing means 150 in the first cam mechanism 131a is in contact with the outer surface of the one-end side biasing force applying portion 172a of the cam position changing portion 171, and the biasing force of the first biasing means 150 is greater than the biasing force of the second biasing means 155. Therefore, both the first cam 136a and the second cam 136b in the first cam mechanism 131a are biased to rotate in the meshing direction, and both the first cam 136a and the second cam 136b are in sliding contact with the first inner ring 110a and the outer ring 120, and either the first cam 136a or the second cam 136b is in a meshing standby state in which it can immediately engage with the first inner ring 110a and the outer ring 120. On the other hand, the first biasing means 150 in the second cam mechanism 131b is not in contact with the cam position changing portion 171, and the biasing force of the first biasing means 150 is released. Therefore, both the first cam 136a and the second cam 136b in the second cam mechanism 131b are biased to rotate in the mesh release direction, and the first cam 136a and the second cam 136b are in a non-contact state separated from the outer circumferential surface of the second inner ring 110b. Therefore, the operation mode of the cam clutch is set to a bidirectional lock mode in which the relative rotational movement of the first inner ring 110a and the outer ring 120 is prohibited in both the forward and reverse directions.

[0059] 19B, when the switching means 170 is moved from the first fixed position to the second fixed position at one axial end side, all of the first biasing means 150 in the first cam mechanism 131a and the second cam mechanism 131b are out of contact with the cam attitude changing portion 171, and the biasing force of the first biasing means 150 is released. Therefore, the first cam 136a and the second cam 136b in the first cam mechanism 131a and the second cam mechanism 131b are both biased to rotate in the mesh release direction, and the first cam 136a and the second cam 136b are in a non-contact state separated from the outer circumferential surfaces of the first inner ring 110a and the second inner ring 110b. Therefore, the operating mode of the cam clutch is switched to a bidirectional free mode which allows relative rotational movement between the first inner ring 110a and the outer ring 120 and between the second inner ring 110b and the outer ring 120 in both forward and reverse directions.

[0060] 19C, when the switching means 170 is moved from the first fixed position to the third fixed position which is further toward one axial end side than the second fixed position, the first biasing means 150 in the first cam mechanism 131a comes out of contact with the cam attitude changing portion 171, and the biasing force of the first biasing means 150 is released. Therefore, both the first cam 136a and the second cam 136b in the first cam mechanism 131a are biased to rotate in the mesh release direction, and the first cam 136a and the second cam 136b are separated from the outer circumferential surface of the first inner ring 110a and come into a non-contact state. On the other hand, the first biasing means 150 in the second cam mechanism 131b comes into contact with the outer surface of the other-end biasing force imparting portion 172b of the cam position changing portion 171, and the biasing force of the first biasing means 150 becomes larger than the biasing force of the second biasing means 155, that is, the biasing force of the second biasing means 155 becomes smaller relative to the biasing force of the first biasing means 150. As a result, both the first cam 136a and the second cam 136b in the second cam mechanism 131b are biased to rotate in the meshing direction, and both the first cam 136a and the second cam 136b come into sliding contact with the second inner ring 110b and the outer ring 120, and the first cam 136a and the second cam 136b are in a meshing standby state in which they can immediately engage with the second inner ring 110b and the outer ring 120. Therefore, the operation mode of the cam clutch is switched to a bidirectional lock mode in which the relative rotational movement of the second inner ring 110b and the outer ring 120 is prohibited in both the forward and reverse directions.

[0061] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above embodiments, and various design modifications can be made without departing from the present invention described in the claims. For example, in the cam clutch according to each of the above embodiments, a configuration including two types of cams, a first cam and a second cam, which have different meshing directions, has been described, but as shown in FIG. 20, a configuration including only one type of cam 136 may be used. In this cam clutch, for example, when the switching means 170 is in the first fixed position, the biasing force of the first biasing means 150 is smaller than the biasing force of the second biasing means 155, or the biasing force of the first biasing means 150 is released, and the cam 136 is in a non-contact state separated from the outer circumferential surface of the inner ring 110. When the switching means 170 is moved from the first fixed position to the second fixed position at one end in the axial direction, the biasing force of the first biasing means 150 is larger than the biasing force of the second biasing means 155, in other words, the biasing force of the second biasing means 155 becomes smaller relative to the biasing force of the first biasing means 150. Therefore, the cam 136 immediately enters an engagement standby state in which it can engage with the inner ring 110 and the outer ring 120. In this way, by applying the present invention to a one-way clutch, it is possible to cause it to function as a selectable clutch that can realize a bidirectional free mode. In the illustrated embodiment, the configuration does not include an interlocking member, but it is also possible to use an interlocking member that interlocks the rotational movements of all of the cams. With such a configuration, there is no variation in the rotational movements of each of the multiple cams, and it is possible to achieve stable operation. [Explanation of symbols]

[0062] 100 ··· Cam clutch 110... Inner circle 110a First inner ring 110b Second inner ring 120 Outer ring 130 Cam mechanism 131a First cam mechanism 131b Second cam mechanism 135 Cam pair 136 Cam 136a First Cam 136b Second cam 137 Rotating shaft portion 138 .... Mounting groove 139a... Notch 139b ··· Stepped section 140 ··· Cage ring 141 Annular plate member 142... Holding hole 143 ... Through hole 144 ... Second biasing means support part 145 Spacer member 150...first biasing means 155...Second biasing means 156a ··· Winding section 156b... Connection part 157 Circular ring 158... Connecting part 159a First leaf spring part 159b Second leaf spring part 160 Cam linkage member 161 ... Base part 162 ... Claw part 170 ··· Switching means 170a First switching means 170b Second switching means 171 Cam position change section 171a First cam position change section 171b Second cam position change section 172 .... Force applying section 172a... One end side biasing portion 172b ... other end side biasing force applying portion 173 .... Force changing section 173a 1st force changing section 173b Second force changing section 174 ··· Force release part 175 Fixing member 175a First fixing member 175b Second fixing member 176a ··· Circular plate 176b ··· Inner protrusion 177a ··· Circular plate 177b ··· Outer protrusion 178 ··· Extension Department

Claims

1. A cam clutch including an inner ring and an outer ring arranged coaxially and relatively rotatably, a plurality of cams arranged between the inner ring and the outer ring, a first biasing means for biasing the cams to rotate in a meshing direction, and a switching means configured to forcibly rotate the cams to switch an operation mode, a second biasing means for biasing the cam so as to rotate in a mesh release direction with a biasing force different in magnitude from the biasing force of the first biasing means, The cam clutch is characterized in that the switching means has a cam position changing portion configured to be able to change the biasing force by one of the first and second biasing means, which has a larger biasing force on the same cam, to be relatively smaller than the biasing force by the other biasing means.

2. 2. The cam clutch according to claim 1, further comprising a cam interlocking member for interlocking the rotational movements of all the cams.

3. The cam includes a first cam and a second cam having mutually different meshing directions, 3. The cam clutch according to claim 2, wherein the cam interlocking member is configured such that, when one of the first cam and the second cam rotates in an engagement direction, the other cam rotates in a disengagement direction.

4. the switching means is provided so as to be movable in the axial direction with the cam position changing portion positioned between adjacent cams, 3. The cam clutch according to claim 1, wherein the cam position changing portion is configured so that the biasing force of the first biasing means against the cam can be changed by axial movement of the switching means.

5. The biasing force of the first biasing means is smaller than the biasing force of the second biasing means for the same cam, 5. The cam clutch according to claim 4, wherein the cam position changing portion is configured to be able to change the state in which the first biasing means can be biased with a biasing force larger than the biasing force of the second biasing means.

6. The biasing force of the first biasing means is greater than the biasing force of the second biasing means for the same cam, 5. The cam clutch according to claim 4, wherein the cam attitude changing portion is configured to be able to change the first biasing means to a state in which it can be biased with a biasing force smaller than the biasing force of the second biasing means or to a state in which the biasing force against the cam is released.

7. 3. A cam clutch according to claim 1, wherein at least one of said first biasing means and said second biasing means is common to each of said plurality of cams.

8. 4. The cam clutch according to claim 3, wherein the switching means includes a first switching means for changing the biasing force of one of the first biasing means and the second biasing means applied to the first cam, and a second switching means for changing the biasing force of one of the first biasing means and the second biasing means applied to the second cam.

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