Cam clutch

Abstract

The purpose of the present invention is to provide a cam clutch capable of stabilizing force application to a cam, improving durability and improving operation stability. Specifically, a biasing means for biasing a cam so as to come into contact with an inner ring and an outer ring is configured by a band-shaped spring formed in such a manner that a base having a cam housing part and a cam biasing part forms a circular ring, and the band-shaped spring has an end structure configured so that the cam housing part and the cam biasing part are in contact with the inner ring and the outer ring. The end portions of the base bodies can be pressed against each other in the circumferential direction, and the end portion structures are configured so as to include contact portions which are formed so as to extend in the radial direction and which are in surface contact with any one of an inner ring, an outer ring, and a spacer ring that holds a cam.

Description

Technical Field

[0001] The present invention relates to a cam clutch provided with a band spring. Background Art

[0002] The cam clutch mainly comprises: a plurality of cams arranged between the inner ring and the outer ring; a retainer for retaining the plurality of cams; and a force applying unit for applying force to each cam in the meshing direction relative to the inner ring and the outer ring, and is constructed so as to transmit and cut off the torque from the driving side to the driven side by engaging and disengaging the plurality of cams with the inner ring and the outer ring according to the relative movement of the inner ring and the outer ring.

[0003] For example, Patent Document 1 discloses a wedge-type one-way clutch using an annular strip spring as a biasing unit. The strip spring is formed into an annular shape by rolling up a longitudinal member, and the longitudinal member has a plurality of wedge receiving holes and a tongue portion for biasing the wedge along the longitudinal direction. The wedge receiving hole disposed at the end closest to the longitudinal direction overlaps with the wedge receiving hole adjacent to the other end edge in the longitudinal direction, and the other end in the longitudinal direction located on the outer diameter side abuts against the retainer.

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2015-152138 Summary of the invention

[0006] Generally, in order to urge each of the plurality of cams with an appropriate urging force, it is preferable to keep the strip spring in a perfect circular shape.

[0007] However, in the strip spring structured as described above, the shape is maintained by making the edge of the other end in the longitudinal direction on the outer diameter side contact with the retainer, so there is a case where the strip spring becomes straight and the circumference of the strip spring changes. Therefore, it is impossible to make the tongue part contact with all the wedges at the appropriate position, and there is a possibility that wedges that are not stressed by the tongue part will be generated. In particular, the stress of the wedges held in the wedge receiving hole closest to one end of the longitudinal member and the wedge receiving hole closest to the other end will easily become unstable, causing these wedges to not contribute to the meshing of the inner ring and the outer ring.

[0008] To address this problem, it may be considered to extend the tongue portion so that the wedge block can be urged with an appropriate force. However, as the tongue portion is extended, stress increases and durability decreases.

[0009] Furthermore, in a selectable clutch capable of switching the operation mode, when the belt spring having the above configuration is used, the load on the cam is likely to be uneven, so that the switching thrust required when switching the operation mode increases, or the cam becomes unable to move depending on the contact position of the tongue portion, making it impossible to switch the operation mode itself.

[0010] The present invention has been made based on the above situation, and the technical problem to be solved is to provide a cam clutch that can stabilize the force applied to the cam and can achieve improved durability and improved operational stability.

[0011] The present invention is a cam clutch, comprising: an inner ring and an outer ring, which are configured to be relatively rotatable on the same axis; a plurality of cams, which are configured between the inner ring and the outer ring; a spacer ring, which holds the cam in the circumferential direction; and a force unit, which applies force to the cam so that it contacts the inner ring and the outer ring. The problem can be solved by the following contents, namely, the force unit is composed of a strip spring, which is formed in a manner that a base forms a circular ring, and the base has a cam force unit that applies force to a cam receiving portion and the cam received in the cam receiving portion, and the force unit has an end structure, and the end structure is configured so that the ends of the base can push each other in the circumferential direction, and the end structure includes a contact portion, which is formed in a manner that extends in the radial direction and is in surface contact with any one of the inner ring, the outer ring and the spacer ring.

[0012] According to the invention involved in the technical solution 1, since the circumferential and radial elastic deformation of the force-adding unit can be suppressed to maintain the expected shape, the displacement of the cam force-adding portion relative to the contact position of the cam and the uneven force-adding to the cam can be avoided. Therefore, all cams can be added with appropriate force, which can improve the stability of the cam clutch operation.

[0013] In addition, the cam energizing part refers to the cam energizing part that energizes the cams held in the cam receiving part closest to one end of the base and the cam receiving part closest to the other end of the base, respectively, and there is no need to increase the length or thickness to increase the spring load. Therefore, the durability of the energizing unit can be improved and the service life can be extended, and the expected energizing unit can be manufactured at a cost-effective manner.

[0014] In addition, when the cam clutch is configured as a selectable clutch, the switching thrust required for switching the operation mode can be reduced, thereby achieving miniaturization and cost reduction of the switching power. Furthermore, since the force can be applied in a manner that makes the postures of all cams uniform, the design of applications such as selectable clutches that require cam posture control becomes easier.

[0015] According to the invention involved in Technical Solution 2, by providing a portion whose rigidity is increased by forming a bent portion in parallel with the cam energizing portion in the axial direction, it is possible to further effectively suppress the misalignment of the abutment position of the cam energizing portion relative to the cam and the uneven energizing of the cam.

[0016] According to the invention according to claim 3 , by forming the bent portion so as to be able to abut against any of the inner ring, the outer ring, and the spacer ring, it is possible to ensure higher morphological stability for the urging unit.

[0017] According to the inventions according to the fourth to sixth aspects of the present invention, it is possible to form an end structure capable of applying force to all cams with appropriate force, and to reliably obtain the expected effect.

[0018] In particular, in the end structure involved in the present technical solution 5, since there is no need to bend the two ends of the base, the expected end structure can be achieved only by punching, so it is easy to manufacture and there is no problem of uncertainty in accuracy caused by bending. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a perspective view showing the structure of a cam clutch according to an embodiment of the present invention by partially cutting away.

[0020] Figure 2 Yes means Figure 1 A cross-sectional view perpendicular to the axis of rotation showing the structure of the cam clutch.

[0021] Figure 3 It is a perspective view showing the structure of the force applying unit.

[0022] Figure 4 It is a cross-sectional view schematically showing the contact state between the cam urging portion and the cam.

[0023] Figure 5 It is a perspective view schematically showing the end structure of the force adding unit.

[0024] Figure 6 It is a schematic diagram for explaining the effect of the end structure on the force unit.

[0025] Figure 7It is a diagram schematically showing an end structure of a biasing unit in a cam clutch according to another embodiment of the present invention.

[0026] Figure 8 It is a schematic representation Figure 7 A top view of the end structure is shown.

[0027] Fig. 9 It is a diagram schematically showing an end structure of a biasing unit in a cam clutch according to still another embodiment of the present invention.

[0028] Explanation of symbols

[0029] 100-cam clutch; 110-inner ring; 120-outer ring; 130-cam; 131-reduced diameter portion; 140-spacer ring; 141-main body; 142-cam retaining portion; 150-force unit; 151-base; 151a-one end; 151b-the other end; 152-cam receiving portion; 153-cam force portion; 154-bending portion; 155-end structure; 156-abutment portion; 157-engaging portion; 158-cam pressing portion; 160-elastic body; 170-action mode switching unit; C-rotation axis. DETAILED DESCRIPTION

[0030] Hereinafter, embodiments of the present invention will be described based on the drawings.

[0031] like Figure 1 and Figure 2 As shown, the cam clutch 100 involved in the present invention comprises: an inner ring 110 and an outer ring 120, which are arranged to be relatively rotatable on the same axis; a plurality of cams 130, which are arranged at intervals in the circumferential direction in the annular space between the inner ring 110 and the outer ring 120; a spacer ring 140, which is arranged between the inner ring 110 and the outer ring 120 to be able to rotate on the same axis together with the outer ring 120 and to hold each of the plurality of cams 130; and a force applying unit 150, which applies force to each of the plurality of cams 130 in the meshing direction so that each of the plurality of cams 130 is in contact with the inner ring 110 and the outer ring 120. Figure 1 and Figure 2 C in the figure is the axis of rotation.

[0032] The cam 130 has a reduced diameter portion 131 at the radial center portion and is configured to be substantially in the shape of a gourd (see Figure 4 The cam 130 in this embodiment is configured to rotate the inner ring 110 in the forward direction ( Figure 2 ) or rotate the outer ring 120 in the reverse direction ( Figure 2 The inner ring 110 and the outer ring 120 can be engaged with each other by rotating in the counterclockwise direction.

[0033] In the present embodiment, for example, the plurality of cams 130 are arranged at equal intervals in the circumferential direction. However, the arrangement of the cams 130 is not particularly limited, and the cams 130 may not be arranged at equal intervals in the circumferential direction.

[0034] The spacer ring 140 includes a cylindrical main body portion 141 extending in the axial direction. The main body portion 141 is provided with cam holding portions 142 arranged in the circumferential direction.

[0035] In the present embodiment, the spacer ring 140 is arranged so that the main body 141 is located on the radially outer ring side and can rotate together with the outer ring 120, and is configured to accommodate the head portion on the radially outer side relative to the reduced diameter portion 131 of the cam 130 to hold the cam 130. The spacer ring 140 may also be arranged so that the main body 141 is located on the radially inner ring side, and is configured to accommodate the foot portion on the radially inner side relative to the reduced diameter portion 131 of the cam 130 to hold the cam 130.

[0036] The urging unit 150 is composed of a strip spring. In the present embodiment, the urging unit 150 is disposed between the inner ring 110 and the spacer ring 140 .

[0037] For example Figure 3 As shown, the strip spring in this embodiment is formed by forming a metal thin plate strip-shaped base 151 into a ring. The base 151 has a cam accommodating portion 152 and a cam urging portion 153 for urging the cam 130 accommodated in the cam accommodating portion 152 .

[0038] The cam receiving portion 152 is formed of, for example, a hole having a rectangular opening shape. The cam urging portion 153 is formed such that a sheet-like portion extending from one end edge in the length direction of the cam receiving portion 152 toward the cam receiving portion 152 constitutes a leaf spring. The cam receiving portion 152 and the sheet-like portion constituting the cam urging portion 153 can be formed, for example, by punching, and the cam urging portion 153 can be formed by bending the sheet-like portion.

[0039] Also like Figure 4 As shown, the cam urging portion 153 is configured to abut against one side surface of the head portion of the cam 130 when the cam 130 is accommodated in the cam accommodation portion 152, and urge the cam 130 in the meshing direction.

[0040] The base 151 has curved portions 154 protruding radially outwardly formed on both side edges of the cam receiving portion 152 so as to be axially parallel to the cam urging portion 153. In this embodiment, the curved portions 154 are formed to be able to abut against the inner peripheral surface of the spacer ring 140, for example.

[0041] The curved portion 154 does not need to be formed so as to be able to abut against the inner circumferential surface of the spacer ring 140, and may be formed so as to protrude inwardly in the radial direction. In addition, when the spacer ring 140 is configured to accommodate the foot portion of the cam 130 and hold the cam 130, and the force applying unit 150 is arranged between the outer ring 120 and the spacer ring 140, the curved portion 154 may be formed so as to protrude inwardly in the radial direction and be able to abut against the outer circumferential surface of the spacer ring 140, or may be formed so as to protrude outwardly in the radial direction and be able to abut against the inner circumferential surface of the outer ring 120.

[0042] Furthermore, the urging unit 150 in the cam clutch 100 having the above-described structure has an end structure 155 configured so that the ends of the base body 151 can be pressed against each other in the circumferential direction.

[0043] like Figure 5 As shown, in the present embodiment, one end 151a and the other end 151b of the base 151 are formed to be bent in the same direction in the radial direction, and are formed to be bent into an arc shape at the top end. By configuring the ends of the base 151 to be circumferentially attached to each other, an end structure 155 including a contact portion 156 is formed. The contact portion 156 is formed in a manner extending in the radial direction and is in surface contact with the spacer ring 140.

[0044] like Figure 6 As shown, since the force unit 150 has such an end structure 155, the one end 151a and the other end 151b of the base 151 push each other in the circumferential direction, so that the circumferential movement of the force unit 150 relative to the cam 130 can be suppressed, and the abutment portion 156 makes surface contact with the spacer ring 140, so that the force unit 150 can be restricted in the radial direction. Therefore, the elastic deformation of the force unit 150 in the circumferential and radial directions can be suppressed to maintain the desired shape, so that the displacement of the abutment position of the cam force unit 153 relative to the cam 130 and the uneven force on the cam 130 can be avoided. In particular, it is possible to effectively avoid the force on the cam 130, which is respectively accommodated in the cam accommodation portion 152 closest to one end of the base 151 and the cam accommodation portion 152 closest to the other end of the base 151, from becoming unstable. Therefore, according to the cam clutch 100 having the above-described structure, all the cams 130 can be urged with appropriate urging force, and the stability of the operation of the cam clutch 100 can be improved.

[0045] In addition, since the morphological stability of the force unit 150 can be improved and all cams 130 can be forced with appropriate force, the cam force unit 153, which refers to the cam force unit 153 for a specific cam 130, such as the cam receiving unit 152 closest to one end of the base 151 and the cam receiving unit 152 closest to the other end of the base 151, does not need to be lengthened or thickened to increase the spring load. Therefore, the durability of the force unit 150 can be improved and the service life can be extended, and the desired force unit 150 can be manufactured at a low cost.

[0046] In the cam clutch 100 of the present invention, the end structure 155 of the force adding unit 150 is not limited to the above-mentioned embodiment, and can also be Figure 7 The composition shown or Fig. 9 The composition shown.

[0047] Figure 7 The end structure 155 of the urging unit 150 shown is formed by the following structure, that is, the one end 151a and the other end 151b of the base 151 are connected by the elastic body 160, and the elastic body 160 can abut against the outer peripheral surface of the main body 141 of the spacer ring 140.

[0048] If the end structure 155 involved in this embodiment is described in detail, it is as follows Figure 8 As shown in the figure, the base 151 of the force applying unit 150 is constructed in a substantially ladder shape, and a clamping portion 157 extending outward in the longitudinal direction is formed in a comb-tooth shape at each of the two ends in the longitudinal direction. The elastic body 160 is composed of, for example, a U-shaped leaf spring, and a through hole capable of inserting the clamping portion 157 of the base 151 is formed on each of the movable pieces connected to the two ends of the curved portion. In the present embodiment, the elastic body 160 is configured such that the curved portion protrudes inward in the radial direction, and the abutting portion 156 is formed by the curved portion abutting against the outer peripheral surface of the spacer ring 140. The top end side portion of each movable piece is bent so as to extend in a direction away from each other with respect to the circumferential direction, and is fixed to the outer peripheral surface of the base 151. The engaging portion 157 at one end of the base 151 and the engaging portion 157 at the other end of the base 151 mesh with each other, and the ends of the base 151 are configured to be able to press against each other in the circumferential direction by elastic deformation of the elastic body 160 .

[0049] Even when using a force unit 150 having such an end structure 155, the circumferential and radial elastic deformation of the force unit 150 can be suppressed to maintain the intended shape, and the misalignment of the abutment position of the cam force portion 153 relative to the cam 130 and the uneven force applied to the cam 130 can be avoided.

[0050] In the present embodiment, the elastic body 160 is described as being able to abut against the outer peripheral surface of the spacer ring 140 , but for example, it may be configured to protrude radially outward so as to abut against the inner peripheral surface of the outer ring 120 .

[0051] also, Fig. 9 The end structure 155 of the urging unit 150 shown is formed by arranging one end 151a and the other end 151b of the base 151 so as to overlap in the radial direction. A curved portion 154 protruding toward the radial inward is formed on the one end side of the cam receiving portion 152 closest to the one end in the longitudinal direction of the base 151, and a contact portion 156 connected to the curved portion 154 and contacting the spacer ring 140 is formed. In addition, in the cam receiving portion 152 closest to the other end in the longitudinal direction of the base 151, a cam pressing portion 158 configured to contact the reduced diameter portion 131 of the cam 130 is formed on the other end edge circumferentially opposite to the one end edge in the longitudinal direction where the cam urging portion 153 is formed. The top end portion of the cam pressing portion 158 is formed along the reduced diameter portion 131 of the cam 130 so as not to hinder the rotation of the cam 130. The other end of the base 151 in the longitudinal direction can come into contact with the bent portion 154 formed on one end side of the base 151 in the longitudinal direction.

[0052] In the force unit 150 having such an end structure 155, the abutting portion 156 abuts against the spacer ring 140 located radially outwardly relative to the force unit 150, and the cam pressing portion 158 abuts against the reduced diameter portion 131 of the cam 130 located radially inwardly relative to the force unit 150, so that the force unit 150 can be restricted in the radial direction. In addition, since the other end of the base 151 abuts against the curved portion 154 on one end side of the base 151 in the circumferential direction, the ends of the base 151 can push each other in the circumferential direction. At this time, since the base 151 can move in the circumferential direction while being restricted in the radial direction, the shape stability of the force unit 150 can be maintained.

[0053] Therefore, even when using a force unit 150 having such an end structure 155, the circumferential and radial elastic deformation of the force unit 150 can be suppressed to maintain the intended shape, and the misalignment of the abutment position of the cam force unit 153 relative to the cam 130 and the uneven force on the cam 130 can be avoided.

[0054] In addition, although Fig. 9 The 170 in the figure is an action mode switching unit that is configured to be driven independently of the rotation of the inner ring 110 and the outer ring 120. However, in a cam clutch that does not have an action mode switching unit, the force adding unit 150 may also be configured to have a configuration such as Fig. 9End structure 155 is shown.

[0055] 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 changes can be made without departing from the scope of the present invention described in the concept.

[0056] The present invention can also be applied to a selectable clutch configured to switch the action mode. In this case, the switching thrust required for switching the action mode can be reduced, and the switching power can be miniaturized and cost-effective. In addition, since the force can be applied in a manner that makes the postures of all cams uniform, the design of applications such as selectable clutches that require cam posture control becomes easier.

Claims

1. A cam clutch comprising: an inner ring and an outer ring, which are arranged to be relatively rotatable on the same axis; a plurality of cams, which are arranged between the inner ring and the outer ring; a spacer ring, which holds the cams in the circumferential direction; and a force applying unit, which applies force to the cams so that they contact the inner ring and the outer ring, characterized in that: The urging unit is composed of a strip spring, wherein the strip spring is formed in a manner that a base forms a circular ring, and the base has a cam urging portion for urging a cam receiving portion and the cam received in the cam receiving portion. The force unit has an end structure, and the end structure is configured so that the ends of the base body can push against each other in the circumferential direction. The end structure includes a contact portion that is formed to extend in the radial direction and is in surface contact with any one of the inner ring, the outer ring, and the spacer ring.

2. The cam clutch according to claim 1, characterized in that: A curved portion convex outward in the radial direction or inward in the radial direction is formed on each of the edge portions on both sides of the base body that define the cam receiving portion so as to be parallel to the cam urging portion in the axial direction.

3. The cam clutch according to claim 2, characterized in that: The bent portion is formed so as to be able to come into contact with any one of the inner ring, the outer ring, and the spacer ring.

4. The cam clutch according to claim 1, characterized in that: The two ends of the base in the longitudinal direction are formed to be bent in the same direction in the radial direction, and the top end is formed to be bent in an arc shape. The abutment portion is formed by arranging the end portions of the base body so as to be in contact with each other in the circumferential direction.

5. The cam clutch according to claim 1, characterized in that: The ends of the base body are connected to each other by an elastic body that protrudes radially outward or radially inward, and the abutment portion is formed by the elastic body.

6. The cam clutch according to claim 1, characterized in that: The urging unit is configured such that the ends of the base are arranged to overlap each other in a radial direction to form a ring. A curved portion protruding radially outward or radially inward is formed on one end side of the base body closer to the cam receiving portion closest to one end in the longitudinal direction, and an abutting portion connected to the curved portion and abutting against any one of the inner ring, the outer ring and the spacer ring is formed. The other end of the base in the longitudinal direction is configured to be able to come into contact with the bent portion.

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