Cam and one-way cam clutch

Abstract

To provide a cam and a one-way cam clutch that have a high degree of freedom in designing a cam center of a gravity position, and excellent responsibility while achieving reduction in weight and manufacturing cost.SOLUTION: In a cam 130 arranged between an inner ring 110 and an outer ring 120 and configured to contact the inner ring 110 and the outer ring 120 by applying a moment in a meshing direction by an annular spring 160, a plurality of cam plates 131 having the same outer contour shape and arranged in parallel in a swing axis direction is integrally connected by a connection pin 135 extending in the swing axis direction. The annular spring 160 is configured to be mountable between the adjacent cam plates 131 and / or at an outside the plurality of cam plates 131 in the swing axis direction. One-way cam clutch 100 has such a cam 130 as an engaging element.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a cam that is provided in an annular space between an inner ring and an outer ring and transmits or interrupts torque between the inner ring and the outer ring, and to a one-way cam clutch that uses the cam as an engagement element. [Background technology]

[0002] A one-way cam clutch is a clutch in which a cam engages between the input and output shafts in one direction to transmit torque, but does not engage in the other direction and spins freely. Taking advantage of this characteristic, it is used in many industrial machines.

[0003] Some types of one-way cam clutches are designed to transmit and block torque from the driving side to the driven side by engaging and disengaging multiple cams (sprags) located in the annular space between the inner and outer rings depending on the relative movement of the inner and outer rings. A known one-way cam clutch of this type has a configuration in which a spring mounting groove extending in the circumferential direction is formed on the inner ring side engagement surface or the outer ring side engagement surface of each of a plurality of cams, and an annular spring is fitted into the spring mounting groove of each of the plurality of cams, thereby applying a moment in the direction in which the cams engage (see, for example, Patent Document 1).

[0004] FIG. 11 is a perspective view showing a configuration example of a conventional cam. The cam 230 is configured such that a spring mounting groove 236 is formed in an outer ring side engagement surface 233, and the biasing force of an annular spring is biased radially inward. 12, the spring mounting groove 236 is formed by two straight grooves 237, 237, and is configured so that the angle of the apex 238 sandwiched by the bottom surfaces of the straight grooves 237, 237 is an obtuse angle. The apex 238 in the spring mounting groove 236 is formed at a position offset toward the meshing direction of the cam 230 with respect to the oscillation shaft, so that the annular spring is always in contact with the apex 238. The spring mounting groove 236 is formed, for example, by using a disk cutter when cutting a steel material such as a round wire that has been machined to a predetermined outer circumferential contour shape to a predetermined thickness. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 9-177840 Summary of the Invention [Problem to be solved by the invention]

[0006] Therefore, in one-way cam clutches, centrifugal force is used to minimize energy loss. From this perspective, the design of the center of gravity position in the cross section perpendicular to the axis of the cam is an important factor, and the shape of each cam needs to be designed according to the performance (application) required of the one-way cam clutch. However, because conventional cams are composed of a single member, the design of the center of gravity position in a cross section perpendicular to the axis of the cam must be carried out by changing the material, shape, size, etc. of the cam, which results in significant constraints on the design of the center of gravity position. Furthermore, in the above-mentioned one-way cam clutch, because of the structure in which multiple cams are restrained by annular springs, it is necessary to machine a spring mounting groove for each of the multiple cams, which increases the processing burden. In addition, the spring mounting grooves must be machined using a dedicated groove processing machine, which increases the manufacturing cost.

[0007] The present invention has been made based on the above circumstances, and aims to provide a cam and one-way cam clutch that achieves weight reduction and reduced manufacturing costs, while offering a high degree of design freedom in the position of the cam center of gravity and excellent responsiveness. [Means for solving the problem]

[0008] The present invention relates to a cam that is arranged in an annular space between an inner ring and an outer ring and is configured to contact the inner ring and the outer ring by applying a moment in the meshing direction by an annular spring, the cam comprising a plurality of cam plates that have the same outer peripheral contour shape and are arranged in parallel in the oscillation axis direction, and a connecting pin that is provided to extend in the oscillation axis direction and connects each of the plurality of cam plates to each other, and the annular spring is configured to be mountable between adjacent cam plates and / or on the outer side of the plurality of cam plates in the oscillation axis direction. The connecting pin is provided so that the center of gravity of the cam is formed at a position offset in the meshing direction or the disengaging direction with respect to a normal line at a contact point between the outer ring side engagement surface of the cam and the raceway surface of the outer ring. Thereby, the above-mentioned problems are solved.

[0009] The present invention also solves the above problem by providing a one-way cam clutch comprising an inner ring and an outer ring arranged coaxially and rotatably relative to each other, a plurality of engaging elements arranged circumferentially in an annular space between the inner ring and the outer ring, and an annular spring that urges the plurality of engaging elements in a meshing direction with the inner ring and the outer ring, wherein each of the plurality of engaging elements is constituted by the above-mentioned cam, and the annular spring is mounted between adjacent cam plates in each of the plurality of engaging elements and / or on the outside of the plurality of cam plates in the axial direction of oscillation. Effect of the Invention

[0010] According to the cam described in claim 1, the position of the center of gravity in the cross section perpendicular to the oscillation axis of the cam can be adjusted by adjusting the position and size of the connecting pins that connect adjacent cam plates, thereby improving the design freedom of the cam center of gravity position and making it possible to flexibly respond to the outer peripheral contour shape of the cam according to the required performance. In addition, since the space where there is no cam plate can be used as the mounting portion for the annular spring, there is no need to machine annular spring mounting grooves during the cam manufacturing process. Also, since each cam plate can be made simultaneously with the pin holes by punching out sheet material, the processing burden is reduced, thereby improving productivity and reducing manufacturing costs. Furthermore, since the portion supporting the annular spring does not have any excess material (unnecessary portion), it is possible to reduce the weight.

[0011] According to the configuration described in claim 2, it is possible to avoid any deviation in the relative positional relationship (attitude of the cam plates) of multiple cam plates, thereby avoiding any difference in the degree of meshing of each cam plate. According to the configuration of claim 3, the connecting pin also serves as a biasing force receiving portion that receives the biasing force from the annular spring, so there is no need to provide a member that constitutes the biasing force receiving portion separately from the connecting member that connects the cam plates, which allows for weight reduction and cost reduction. Also, since it is only necessary to perform simple hole processing on the cam plates, the processing burden can be reduced, and in this respect, too, productivity can be improved and manufacturing costs can be reduced. According to the configuration of the present invention, since the biasing force from the annular spring can be appropriately applied in the meshing direction of the cam, the attitude of the cam can be stably maintained. According to the configuration of the present invention, since the biasing means support plate does not come into contact with the inner ring and the outer ring, it is possible to reduce friction loss.

[0012] According to the one-way cam clutch described in claim 6, by using the cam having the above-mentioned configuration as an engaging element, it is possible to achieve weight reduction and reduced manufacturing costs while obtaining excellent responsiveness and the desired torque transmission performance. [Brief description of the drawings]

[0013] [Figure 1] 1 is a cross-sectional view taken in a direction perpendicular to a rotation axis, illustrating a schematic configuration of a portion of an example of a one-way cam clutch according to the present invention. FIG. [Diagram 2] 2 is a cross-sectional view taken along a rotation axis of the one-way cam clutch shown in FIG. 1. [Diagram 3] 2 is a perspective view showing a configuration of a cam in the one-way cam clutch shown in FIG. 1. [Figure 4] FIG. 4 is an exploded perspective view of the cam shown in FIG. 3. [Diagram 5]4 is a plan view of the cam shown in FIG. 3 as viewed from the swing axis direction. [Figure 6A] 2 is a cross-sectional view showing a schematic state (posture) of a cam when the one-way cam clutch shown in FIG. 1 is engaged. [Figure 6B] 2 is a cross-sectional view showing a schematic state (posture) of a cam during idling of the one-way cam clutch shown in FIG. 1. FIG. [Figure 7] FIG. 11 is a perspective view showing another example of the configuration of the cam of the present invention. [Figure 8] FIG. 8 is an exploded perspective view of the cam shown in FIG. [Figure 9] 8 is a cross-sectional view of the cam shown in FIG. 7 taken in a direction perpendicular to the oscillation axis. [Figure 10] FIG. 11 is a perspective view showing still another configuration example of the cam of the present invention. [Figure 11] FIG. 11 is a perspective view showing a configuration example of a conventional cam. [Figure 12] 12 is a cross-sectional view of the cam shown in FIG. 11 taken in a direction perpendicular to the oscillation axis. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] As shown in Figures 1 and 2, the one-way cam clutch 100 of the present invention comprises an inner ring 110 and an outer ring 120 which are arranged on the same axis so as to be rotatable relative to each other, a plurality of cams 130 which are arranged circumferentially in the annular space between a raceway surface 111 of the inner ring 110 and a raceway surface 121 of the outer ring 120 and serve as engaging elements for transmitting and blocking torque between the inner ring 110 and the outer ring 120, a cam cage 150 which holds each of the plurality of cams 130 so that they can swing freely at positions arranged at predetermined intervals in the circumferential direction, and annular springs 160 which bias each of the plurality of cams 130 in the direction of engagement with the inner ring 110 and the outer ring 120.

[0015] 3 and 4, each of the multiple cams 130 is composed of two cam plates 131 arranged in parallel in the oscillation axis direction, and a connecting pin 135 that is provided to extend in the oscillation axis direction and connects each of the two cam plates 131 to each other. With this configuration, it is possible to adjust the position of the center of gravity of the cam 130 in a cross section perpendicular to the oscillation axis by adjusting the position and size of the connecting pin 135, thereby improving the design freedom of the center of gravity of the cam 130 and making it possible to flexibly accommodate the outer peripheral contour shape of the cam 130 according to the required performance. In this embodiment, as shown in FIG. 5, the position of the connecting pin 135 is set so that the center of gravity G of the cam 130 is formed at a position offset in the meshing direction with respect to the normal H at the contact point C between the outer wheel side engagement surface 133 of the cam 130 and the raceway surface 121 of the outer wheel 120.

[0016] Each cam plate 131 has the same outer peripheral contour shape. This eliminates the difference in the degree of meshing between the cam plates 131, making it possible to reduce friction loss. It also makes it possible to improve productivity and reduce manufacturing costs. As shown in Fig. 5, the cam plate 131 has an inner ring side engagement surface 132 that abuts against the raceway surface 111 of the inner ring 110, and an outer ring side engagement surface 133 that abuts against the raceway surface 121 of the outer ring 120. The cross-sectional shape of the inner ring side engagement surface 132 is, for example, an arc, and the cross-sectional shape of the outer ring side engagement surface 133 is a curve that includes an arc-shaped portion with a smaller radius of curvature than the inner ring side engagement surface 132. Note that in Fig. 5, the raceway surface 111 of the inner ring 110 and the raceway surface 121 of the outer ring 120 are shown as parallel planes for the sake of convenience.

[0017] A pin hole 134 is formed in the cam plate 131 so as to penetrate therethrough in the thickness direction, and a connecting pin 135 is press-fitted into the pin hole 134 so that the two cam plates 131 are fixed together. With this configuration, it is possible to prevent deviations in the relative positional relationship (attitude of cam plate 131) between the two cam plates 131, and therefore to prevent differences in the degree of meshing between the cam plates 131. Also, since each cam plate 131 can be made simultaneously with pin holes 134 by punching out a plate material, also in this respect, it is possible to reduce the processing burden, improve productivity, and reduce manufacturing costs. In this embodiment, for example, a cylindrical connecting pin is used as the connecting pin 135, and therefore the pin hole 134 has a circular opening shape and is configured to have a hole diameter of a uniform size in the thickness direction.

[0018] Thus, each cam 130 is configured so that the annular spring 160 can be mounted between the two cam plates 131. That is, in the cam 130 of this embodiment, the space where there are no cam plates 131 can be used as a mounting portion for the annular spring 160, so machining of an annular spring mounting groove is not required in the manufacturing process of the cam 130, which reduces the processing burden and improves productivity while reducing manufacturing costs. In the cam 130 of this embodiment, the connecting pin 135 is configured to come into contact with the annular spring 160 and receive the biasing force from the annular spring 160. Since the connecting pin 135 also serves as a biasing force receiving portion that receives the biasing force from the annular spring 160, there is no need to provide a member that configures the biasing force receiving portion separately from the connecting member that connects the cam plates 131, making it possible to reduce weight and costs. Also, since the portion that supports the annular spring 160 is configured to have no excess material (unnecessary portion), it is possible to reduce weight.

[0019] In the one-way cam clutch 100 of this embodiment, for example, an annular garter spring is used as the annular spring 160, and when each of the multiple cams 130 is placed in the housing of the cam cage 150, the garter spring is attached from the outer ring side engagement surface 133 side of the cam 130, thereby biasing each of the multiple cams 130 radially inward (see FIG. 6A). By restraining each of the multiple cams 130 with the garter spring, all of the cams 130 are stably held without variation in posture (inclination).

[0020] Thus, in the above-mentioned one-way cam clutch 100, as shown in FIG. 6A, the inner ring engagement surface 132 of the cam 130 is in contact with the raceway surface 111 of the inner ring 110 and the outer ring side engagement surface 133 of the cam 130 is in contact with the raceway surface 121 of the outer ring 120 due to the biasing force F1 from the annular spring 160, and when the outer ring 120 rotates in one direction (counterclockwise in FIG. 6A), the inner ring side engagement surface 132 of the cam 130 frictionally engages with the raceway surface 111 of the inner ring 110 and the outer ring side engagement surface 133 of the cam 130 frictionally engages with the raceway surface 121 of the outer ring 120, thereby transmitting torque between the inner ring 110 and the outer ring 120. On the other hand, as shown in Fig. 6B, when outer race 120 rotates in the other direction (clockwise in Fig. 6B), cam 130 receives a predetermined centrifugal force F2, and cam 130 swings against the rotation moment due to the biasing force F1 of annular spring 160, and cam 130 is lifted up relative to inner race 110 by centrifugal force F2. As a result, inner race side engagement surface 132 of cam 130 and raceway surface 111 of inner race 110 are brought into a non-contact state, and torque transmission between inner race 110 and outer race 120 is interrupted. This makes it possible to prevent wear of inner race side engagement surface 132 and outer race side engagement surface 133 of cam 130 during high-speed idling.

[0021] 7 and 8 are diagrams showing other configuration examples of the cam. The cam 130 further includes a biasing means support plate 140 configured to come into contact with the annular spring and receive the biasing force from the annular spring. In Figures 7 and 8, the same components as those in Figures 3 to 5 are denoted by the same reference numerals, and the description thereof will be omitted.

[0022] The biasing means support plate 140 has a pin hole 141 that penetrates in the thickness direction, and a connecting pin 135 that connects the two cam plates 131, 131 is pressed into the pin hole 141, thereby fixing the biasing means support plate 140 integrally with the two cam plates 131, 131.

[0023] As shown in FIG. 9, the biasing means support plate 140 has a planar shape, for example, in which a part of a disk is cut out by two planes perpendicular to the disk and intersect so that the apex angle is an obtuse angle, and the apex sandwiched between the two planes forms a biasing force receiving portion that receives the biasing force from the annular spring 160.

[0024] In this embodiment, the biasing means support plate 140 is disposed between the two cam plates 131, 131, and is configured so that the annular spring can be attached between the two cam plates 131, 131. By providing the biasing means support plate 140, it is possible to cause the biasing force from the annular spring to act appropriately in the meshing direction of the cam 130. In addition, the biasing means support plate 140 is positioned inside the outer peripheral edge of the cam plate 131, so that the biasing means support plate 140 does not come into contact with the inner ring 110 and the outer ring 120, making it possible to reduce friction loss.

[0025] Although one embodiment of the present invention has been described in detail above, the present invention is not limited to the above embodiment, and various design modifications can be made without departing from the present invention described in the claims. For example, in the above embodiment, the annular spring is configured to be mounted between two cam plates, but the connecting pin may be arranged so that its end protrudes from the outer end face of the cam plate, and the annular spring may be configured to be mounted on the outside of the cam plate in the axial direction of its oscillation. Furthermore, although the two cam plates are configured to be connected by one connecting pin, they may be configured to be connected by two or more connecting pins. Furthermore, the number of cam plates is not limited to two, and may be three or more. An example of the configuration of a cam with three cam plates is shown in Fig. 10. In this cam 130, the space between two adjacent cam plates 131, 131 can be used as a mounting portion for annular springs, and therefore, two annular springs can be mounted. This makes it possible to reliably impart to the cam 130 an urging force suitable for the required function.

[0026] In the above embodiment, the cross-sectional shape of the connecting pin and the opening shape of the pin hole are circular, but the cross-sectional shape of the connecting pin and the opening shape of the pin hole are not limited to circular, and may be, for example, polygonal, elliptical, or oval, as long as they are easy to manufacture. When the cross-sectional shape of the connecting pin and the opening shape of the pin hole are polygonal, it is possible to more reliably obtain the anti-rotation function that prevents the relative rotation of the two cam plates. In addition, the connecting pin does not need to be cylindrical with a uniform outer diameter in the axial direction, and may have a portion with a different outer diameter. The connecting pin is configured as a separate member from the cam plate, but may be configured integrally with one of the cam plates. Furthermore, in the above embodiment, the annular spring is provided to urge each of the multiple cams radially inward, but the annular spring may be configured to urge each of the multiple cams radially outward. Also, the annular spring is not limited to a garter spring as long as it urges each of the multiple cams in a direction to mesh with the inner and outer rings.

[0027] In addition, in the above embodiment, the cam is configured as a disengage type, but it may be configured as an engage type in which the center of gravity of the cam is designed so that the cam engages by centrifugal force. Furthermore, the one-way cam clutch of the present invention may be configured without including a retainer (cam cage). [Explanation of symbols]

[0028] 100 ··· One-way cam clutch 110... Inner circle 111 ... Raceway surface 120 Outer ring 121 ... raceway surface 130,230 ··· Cam 131 Cam plate 132 Inner ring side engagement surface 133,233 Outer ring engagement surface 134 Pin hole 135 ··· Connecting pin 236 Spring mounting groove 237 Straight groove 238 ... top 140 .... Biasing means support plate 141 Pin hole 150 ··· Cam cage 160 ··· Annular spring

Claims

1. A cam is disposed in an annular space between an inner ring and an outer ring, and configured to come into contact with the inner ring and the outer ring by applying a moment in a meshing direction by an annular spring, a plurality of cam plates each having the same outer peripheral contour shape and arranged in parallel in a swing axis direction; and a connecting pin extending in the swing axis direction and connecting each of the plurality of cam plates to each other, The annular spring is configured to be mountable between adjacent cam plates and / or on the outer side of the plurality of cam plates in the swing axial direction, The connecting pin is arranged so that the center of gravity of the cam is formed at a position biased in the engagement direction or the disengagement direction with respect to the normal at the point of contact between the outer ring side engagement surface of the cam and the raceway surface of the outer ring.

2. Each of the plurality of cam plates is formed with a pin hole penetrating in a thickness direction, 2. The cam according to claim 1, wherein the plurality of cam plates are fixed together by press-fitting the connecting pin into the pin hole.

3. 3. The cam according to claim 1, wherein the connecting pin is configured to come into contact with the annular spring and receive a biasing force from the annular spring.

4. a biasing means support plate fixed integrally to an adjacent cam plate by the connecting pin; 3. The cam according to claim 1, wherein the biasing means support plate is configured to come into contact with the annular spring and receive a biasing force from the annular spring.

5. 5. The cam according to claim 4, wherein said biasing means support plate is located inside the outer periphery of the cam plate.

6. A one-way cam clutch comprising an inner ring and an outer ring arranged coaxially and rotatably relative to each other, a plurality of engaging elements arranged in a circumferential direction in an annular space between the inner ring and the outer ring, and an annular spring that biases the plurality of engaging elements in a meshing direction with the inner ring and the outer ring, A one-way cam clutch, characterized in that each of the plurality of engaging elements is constituted by a cam as set forth in any one of claims 1 to 5, and the annular spring is attached between adjacent cam plates in each of the plurality of engaging elements and / or on the outer side of the plurality of cam plates in the axial direction of oscillation.

Images