Reverse input shutting-off clutch

Abstract

To provide a reverse input shutting-off clutch that facilitates manufacturing or assembling, can stably perform lock operation when reverse input torque is added, and can release a reverse input shutting-off function when needed.SOLUTION: When input torque is added, a cam receiver 2 integrated with an input shaft 1 presses a spacer 5 slidably fitted in an eccentric hole 2a. The spacer 5 is supported by an Oldham joint 7 to revolve, thereby integrally rotating an eccentric cam 4 and an output shaft 3. With respect to reverse input torque, the spacer 5 is regulated in revolving and swiveling motion, and two rolling bearings 17 and 18 of a braking mechanism 8 receive a preload to generate braking force to rotations of the input shaft 1, thereby stably locking the output shaft 3. A lock releasing mechanism 9 is provided, which moves a positioning member 16 positioning the rolling bearings 17 and 18 in an axial direction to make the input shaft 1 abut on the eccentric cam 4 so as to transmit rotations, thereby releasing a reverse input shutting-off function.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a locking type reverse input cut-off clutch which transmits the rotation of an input side member to an output side member when an input torque is applied, and locks the output side member against a reverse input torque to prevent the input side member from rotating. [Background technology]

[0002] In industrial machinery, when a part or the like is positioned by a motor-driven positioning device, even after the part or the like is moved to a stop position and the rotation of the motor is stopped, current is passed through the motor so that the positioning device will hold the part or the like in the stop position even if it is subjected to an external force, which consumes power. If a locking reverse input cutoff clutch is incorporated into such a positioning device, the positioning device can hold the part or the like in the stop position by locking against the force applied by the part or the like after positioning is completed, so that power can be saved by cutting off current to the motor as soon as positioning is completed. Another advantage is that even if the positioning device suddenly stops due to a power outage or the like, the positioning device is held in the stop position by the action of the reverse input cutoff clutch, ensuring safety.

[0003] An example of such a lock type reverse input cutoff clutch is described in Patent Document 1. This reverse input cutoff clutch is provided with a torque transmission means between an input member and an output member that rotate around the same axis, which transmits the rotation of the input member to the output member with a slight angular delay, a fixed outer ring having a cylindrical surface on the inner circumference is disposed on the radial outside of the output member, and a plurality of cam surfaces are provided on the outer circumference of the output member, forming wedge-shaped spaces that gradually narrow on both sides in the circumferential direction between the inner circumference cylindrical surface of the fixed outer ring and each cam surface of the output member, and incorporating a pair of rollers and a spring that presses the rollers into the narrow part of the wedge-shaped space in each of these wedge-shaped spaces, and connecting a retainer having a column portion inserted on both sides in the circumferential direction of each wedge-shaped space to rotate integrally with the input member. Here, the radial direction is a direction perpendicular to the common axis of the input member and the output member, and the circumferential direction is a direction along a circumference that goes around the axis. The direction along the axis is also called the axial direction. The definitions of these directions are the same in the following description.

[0004] However, the reverse input cut-off clutch of Patent Document 1 mentioned above has the drawback that complex processing (forming a cam surface) is required when manufacturing the output side member, and that it is time-consuming to incorporate small parts such as rollers and springs into the multiple wedge-shaped spaces during assembly.

[0005] In response to this, the inventors of the present invention have devised a reverse input cutoff clutch having a structure as shown in Figures 8 and 9 (Patent Application No. 2015-107078). In this reverse input cutoff clutch, an input shaft 51 and an output shaft 53 through which a fixed shaft 55 passes are arranged coaxially, a cylindrical eccentric cam 54 having an eccentric axis parallel to the axis of the output shaft 53 is provided on the input shaft 51, a cylindrical cam receiver 52 which slides against the inner peripheral surface of a housing (fixed member) 57 is provided on the input shaft 51, a circular eccentric hole 52a having the same eccentric axis as the eccentric axis of the eccentric cam 54 is formed in the cam receiver 52, the eccentric cam 54 is inserted into the eccentric hole 52a, a cylindrical spacer 56 is slidably fitted between the inner peripheral surface of the eccentric hole 52a and the outer peripheral surface of the eccentric cam 54, and an Oldham joint (swivel support mechanism) 58 which supports the spacer 56 non-rotatable but revolvable is provided between the spacer 56 and the housing 57.

[0006] The housing 57 has a lid 59 fitted onto the inner periphery at one end and a lid portion 57a ​​at the other end. The Oldham joint 58 has a connecting member 60 disposed between the spacer 56 and the lid portion 57a ​​of the housing 57, so that the connecting member 60 slides between the spacer 56 and the lid portion 57a ​​of the housing 57.

[0007] When input torque is applied to the input shaft 51, the cam receiver 52 receiving a couple of forces from the input shaft 51 presses the spacer 56, and the spacer 56 slides up and down guided by a connecting member 60 constituting an Oldham joint 58, while at the same time the connecting member 60 slides left and right guided by a housing 57, causing the spacer 56 to revolve without rotating on its axis, and the eccentric cam 54 fitted on the inner periphery of the spacer 56 and the output shaft 53 to rotate together. At this time, the cam receiver 52 rotates in a braked state due to the sliding resistance against the housing 57.

[0008] On the other hand, when a reverse input torque is applied to the output shaft 53, the eccentric cam 54 integral with the output shaft 53 presses the cam receiver 52 via the spacer 56. However, this pressing force is not a couple force, but a translational force acts on the cam receiver 52 and the spacer 56. As a result, the connecting member 60 of the Oldham joint 58 cannot slide, and the revolutionary motion of the spacer 56 is restricted, causing the output shaft 53 to be locked.

[0009] Compared to conventional locking clutches that incorporate multiple small rollers and springs, this reverse input cut-off clutch eliminates the need for complex processing when manufacturing the parts and reduces the number of parts, making it easier to manufacture and assemble. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] Japanese Patent Application Publication No. 2-271116 Summary of the Invention [Problem to be solved by the invention]

[0011] 8 and 9, when a reverse input torque is applied to the output shaft 53, the force transmitted from the output shaft 53 to the cam receiver 52 via the eccentric cam 54 and the spacer 56 does not rotate the cam receiver 52 and the input shaft 51, as described above. Also, the input side member consisting of the input shaft 51 and the cam receiver 52 and the output side member consisting of the output shaft 53 and the eccentric cam 54 are assembled so as to be in contact with each other, and although the frictional force between the input side member and the output side member tends to rotate the input side member, the design is such that the braking force due to the sliding resistance of the cam receiver 52 against the housing 57 is greater than the frictional force, thereby preventing the output side member and the input side member from rotating together.

[0012] However, when used under conditions in which input shaft 51 rotates at high speed due to motor drive or the like, the outer peripheral surface of cam receiver 52 and the inner peripheral surface of housing 57 will wear during use, increasing the gap between them and reducing the sliding resistance (braking force) of cam receiver 52, causing the frictional force between the input side member and the output side member to rotate the input side member (to rotate together with the output side member), which may result in a locking failure of output shaft 53.

[0013] Furthermore, since there is no mechanism for releasing the function that locks the output side member against reverse input torque (hereinafter referred to as the "reverse input blocking function"), there is a drawback that if a device incorporating this reverse input blocking clutch is brought to an emergency stop due to a power outage or the like, it is not possible to operate the device by moving the output side member manually, for example.

[0014] Therefore, an object of the present invention is to provide a reverse input cut-off clutch that is easy to manufacture and assemble, can stably perform locking operation when reverse input torque is applied, and can release the reverse input cut-off function as necessary. [Means for solving the problem]

[0015] In order to solve the above-mentioned problems, the present invention provides a transmission comprising an input shaft and an output shaft arranged to rotate about the same axis, a cylindrical eccentric cam having an eccentric axis parallel to the axis of the output shaft and provided on the output shaft to rotate integrally with the output shaft, a cam receiver provided on the input shaft to receive the eccentric cam in a circular eccentric hole having the same eccentric axis as the eccentric axis of the eccentric cam and to rotate integrally with the input shaft, a cylindrical spacer slidably fitted between an inner peripheral surface of the eccentric hole of the cam receiver and an outer peripheral surface of the eccentric cam, a fixed member which rotatably supports the input shaft and the output shaft, a rotation support mechanism which is provided between the spacer and the fixed member and supports the spacer non-rotatable but revolvable, and a braking mechanism which applies a brake to the rotation of an input side member consisting of the input shaft and the cam receiver, and when an input torque is applied to the input shaft, a couple of forces act on the cam receiver from the input shaft, In a reverse input blocking clutch in which the spacer revolves around the eccentric cam, causing the eccentric cam and the output shaft to rotate together, and when a reverse input torque is applied to the output shaft, a translational force acts from the output shaft to the cam receiver and the spacer via the eccentric cam, restricting the revolving motion of the spacer and locking the output shaft, the braking mechanism employs a configuration (configuration 1) in which two rolling bearings are arranged to radially sandwich a positioning portion of a positioning member supported by the fixed member, the positioning member positions the radially outer rolling bearing between the input side member, and the positioning member moves in the axial direction toward the eccentric cam to abut the input side member against the eccentric cam via the radially outer rolling bearing so as to transmit rotation, thereby providing an unlocking mechanism to prevent the output shaft from locking.

[0016] According to the above configuration 1, the number of parts can be reduced and manufacturing and assembly can be facilitated compared to conventional locking types incorporating multiple small rollers and springs. Also, even when used under conditions where the input shaft is driven by a motor, the preload applied to the rolling bearing of the braking mechanism does not change during use and the braking force against the rotation of the input side member is kept constant, so that when a reverse input torque is applied to the output shaft, the output shaft can be stably locked by the action of restricting the revolutionary motion of the spacer and the braking force of the braking mechanism.

[0017] Furthermore, since an unlocking mechanism is provided which releases the reverse input blocking function, even when a device incorporating this reverse input blocking clutch is stopped in an emergency, the unlocking mechanism can be activated and a reverse input torque applied to rotate both the output side member and the input side member consisting of the output shaft and eccentric cam, thereby easily changing the position of the device and improving the operability of the device in a stopped state.

[0018] In the above configuration 1, the unlocking mechanism may be one in which the positioning member is connected to an operating member that is screwed to the fixed member so as to be unable to rotate relative to the fixed member and to move together with the fixed member in the axial direction, and the positioning member is moved in the axial direction by rotating the operating member (configuration 2). Alternatively, the positioning member may be biased in the axial direction away from the eccentric cam by a positioning spring disposed between the fixed member and the positioning member, and the positioning member is moved in a direction approaching the eccentric cam by pressing the positioning member from the side opposite to the positioning spring with an unlocking tool (configuration 3).

[0019] In any of the above configurations 1 to 3, the axial contact surfaces of the input member and the eccentric cam may be opposed to each other with sticky oil interposed therebetween, or may be formed with interlocking projections and recesses (configuration 4). In this way, when the unlocking mechanism is operated to apply reverse input torque, friction between the input member and the eccentric cam increases, and the output member can be rotated together with the input member more reliably. Effect of the Invention

[0020] As described above, the reverse input cutoff clutch of the present invention is easier to manufacture and assemble than conventional locking types, and can stably perform the locking operation when reverse input torque is applied. Also, since the reverse input cutoff function can be released as needed by the lock release mechanism, a device incorporating this reverse input cutoff clutch can be easily operated manually from the output side even in the event of an emergency stop, etc. [Brief description of the drawings]

[0021] [Figure 1] FIG. 1 is a cross-sectional plan view of a reverse input cutoff clutch according to a first embodiment in a used state; [Diagram 2] FIG. 2 is an exploded perspective view of the reverse input cutoff clutch of FIG. [Diagram 3] a is a cross-sectional view taken along line III-III in FIG. 1, and b is a cross-sectional view corresponding to a that explains the clutch operation. [Figure 4] FIG. 2 is a cross-sectional plan view illustrating the operation of the lock release mechanism corresponding to FIG. 1; [Diagram 5] FIG. 11 is a cross-sectional plan view of a reverse input cutoff clutch according to a second embodiment in use; [Figure 6] FIG. 6 is an exploded perspective view of a main part of the reverse input cutoff clutch of FIG. [Figure 7] FIG. 6 is a cross-sectional plan view illustrating the operation of the lock release mechanism corresponding to FIG. 5 . [Figure 8] A cross-sectional plan view of a reverse input cutoff clutch on which the present invention is based. [Figure 9] FIG. 9 is an exploded perspective view of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Hereinafter, an embodiment of the present invention will be described with reference to Fig. 1 to Fig. 7. Fig. 1 to Fig. 4 show a first embodiment (Fig. 1 and Fig. 4 show a state in which the clutch is connected to a motor M). This reverse input cutoff clutch is basically composed of a cylindrical input shaft 1, a cylindrical cam receiver 2 integrally formed with a flange portion on one end side of the input shaft 1, an output shaft 3 having the other end side fitted into the inner circumference of the input shaft 1, a cylindrical eccentric cam 4 integrally formed with the center portion in the axial direction of the output shaft 3, a cylindrical spacer 5 slidably fitted between the inner circumference surface of the cam receiver 2 and the outer circumference surface of the eccentric cam 4, a housing (fixed member) 6 that rotatably supports the input shaft 1 and the output shaft 3, an Oldham joint (rotation support mechanism) 7 that is disposed between the spacer 5 and the housing 6 and supports the spacer 5 so that it cannot rotate on its own axis but can revolve around it, a braking mechanism 8 that brakes the rotation of an input side member consisting of the input shaft 1 and the cam receiver 2, and a lock release mechanism 9 that releases the reverse input cutoff function by bringing the input side member into contact with the eccentric cam 4 in the axial direction as described later.

[0023] The input shaft 1 and the output shaft 3 are arranged to rotate about the same axis, and the cam receiver 2 integral with the input shaft 1 also has the same axis as the axis of the input shaft 1. On the other hand, the eccentric cam 4 integral with the output shaft 3 has an eccentric axis parallel to the axis of the output shaft 3, and the cam receiver 2 has an eccentric axis identical to that of the eccentric cam 4, and is formed with a circular eccentric hole 2a that receives the spacer 5 and the eccentric cam 4.

[0024] The housing 6 has a lid portion 6b at one end of a cylindrical portion 6a through which the output shaft 3 passes, a joint member 10 serving as a connecting part with the motor M is fitted to the other end of the cylindrical portion 6a, and the cam receiver 2, the eccentric cam 4, and the spacer 5 are housed inside. The housing 6 is connected to the motor M by a bolt 11 that passes through the lid portion 6b, the cylindrical portion 6a, the joint member 10, and the outer periphery of the motor M, and a nut 12 that is screwed onto the bolt 11. The lid portion 6b has a plurality of protrusions 6c provided at equal intervals in the circumferential direction on its outer periphery, and the protrusions 6c have through holes formed therein for fixing the housing 6 to an external member E with a bolt 13.

[0025] The joint member 10 has a shape in which a first annular portion 10a that fits into the other end of the cylindrical portion 6a of the housing 6 and a second annular portion 10b that fits into the outer periphery of one end of the motor M are connected by a plurality of column portions 10c extending in the axial direction, and a bolt 11 for connecting the motor M is passed through each column portion 10c, and a radially penetrating window 10d is formed between adjacent column portions 10c in the circumferential direction.

[0026] The housing 6 rotatably supports the output shaft 3 via a rolling bearing 14 assembled between the cover 6b at one end and the output shaft 3. At the other end, a plurality of operating members 15 constituting a part of the unlocking mechanism 9 are screwed to a male thread 6d formed on the outer periphery of the cylindrical portion 6a, and the input shaft 1 is rotatably supported via two rolling bearings 17, 18 assembled between a positioning member 16 to which the operating members 15 are attached and the input shaft 1. In this example, the rolling bearings 14, 17, 18 are deep groove ball bearings. A gap is provided between the inner circumferential surface of the cylindrical portion 6a of the housing 6 and the outer circumferential surface of the cam receiver 2, so that the input side member does not slide against the housing 6.

[0027] The input shaft 1 has a recess on the other end surface into which the motor shaft of the motor M is inserted, and is connected to the motor shaft so as to be rotatable together with the motor shaft by a key that fits into a key groove 1a provided on the inner circumference of the recess. An annular groove 1b is provided on the outer circumference axially inward from the key groove 1a, and an annular spring bearing 19 that fits into the annular groove 1b supports a coil-shaped preload spring (preload member) 20 that biases the inner ring of the radially inner rolling bearing 18 axially inward. A plurality of groove-shaped oil reservoirs 1c extending in the axial direction are provided on the inner circumference of the portion excluding the recess on the other end side, and sticky oil filled in the oil reservoirs 1c flows into between the flange portion at one end of the input shaft 1 and the eccentric cam 4.

[0028] Furthermore, a plurality of hooks 1d, which extend axially outward and have their tips bent radially inward, are provided at equal intervals around the periphery of the flange of the input shaft 1, and the outer ring of the radially outer rolling bearing 17 is snap-fitted onto the inner periphery of a positioning portion formed by these plurality of hooks 1d. This positioning portion of the input shaft 1 positions the radially outer rolling bearing 17 together with the aforementioned plurality of operating members 15 and positioning member 16.

[0029] The operating member 15 has a shape that forms a portion of the circumference of a cylinder and consists of a main body portion 15a with a female thread portion formed on the inner circumference at one end, an attachment portion 15b that protrudes inward from the other end of the main body portion 15a, and a convex portion 15c that protrudes from the inner surface of the attachment portion 15b.

[0030] The positioning member 16 has a cylindrical portion 16a disposed radially inside the joint member 10, and a plurality of hooks 16b extending axially inward with tips bent radially to both sides are provided at equal intervals in the circumferential direction on the inner peripheral portion of the cylindrical portion 16a, and the inner ring of the rolling bearing 17 on the radially outer side is snap-fitted onto the outer peripheral side of the positioning portion formed by the plurality of hooks 16b. In addition, recesses 16c into which the protrusions 15c of the operating member 15 are fitted are provided at multiple points on the outer peripheral surface of the flange formed on the other end side of the cylindrical portion 16a.

[0031] Each operating member 15 is fixed by fitting a convex portion 15c of the mounting portion 15b into a concave portion 16c on the outer periphery of the positioning member 16 with the mounting portion 15b of each operating member 15 inserted inward through a window 10d of the joint member 10 and the female thread portion of the main body portion 15a screwed into the male thread portion 6d of the housing 6. As a result, the positioning member 16 is supported by the housing 6 in a connected state so as to be unable to rotate relative to each operating member 15 and to move integrally with the operating member 15 in the axial direction.

[0032] The braking mechanism 8 includes the above-mentioned positioning member 16, two rolling bearings (hereinafter also simply referred to as "bearings") 17, 18, and a preload spring 20. The two bearings 17, 18 are arranged on the outside and inside so as to sandwich the positioning portion of the positioning member 16 in the radial direction.

[0033] The radially outer bearing 17 is positioned by snap-fitting its outer ring into a positioning portion of the input shaft 1 and its inner ring into a positioning portion of the positioning member 16. Meanwhile, the radially inner bearing 18 is positioned by its outer ring abutting the inwardly bent portions of the hooks 16b of the positioning member 16 and its inner ring abutting one end of a preload spring 20. A preload is applied to the radially inner bearing 18 by the elastic force of the preload spring 20, and also to the radially outer bearing 17 via the radially inner bearing 18 and the positioning member 16, thereby increasing the rotational torque of each bearing 17, 18 and braking the rotation of the input side member.

[0034] In addition, a disk-shaped connecting member 21 that constitutes part of the Oldham joint 7, as described below, is disposed at a position axially sandwiched between the cover portion 6b of the housing 6 and an inward flange-like connecting portion 5a provided at one end of the spacer 5.

[0035] The Oldham joint 7 is configured such that a first concave-convex fitting portion is provided on the axially opposing surfaces of the connecting member 21 and the connecting portion 5a of the spacer 5, the first fitting portion extending in the radial direction of the spacer 5 and fitting slidably into each other, and a second fitting portion is provided on the axially opposing surfaces of the connecting member 21 and the cover portion 6b of the housing 6, the second fitting portion extending in a direction perpendicular to the first fitting portion and fitting slidably into each other.

[0036] Here, the first concave-convex fitting portion consists of a recess 5b formed to extend radially on the outer surface (axially opposing surface) of the connecting portion 5a of the spacer 5, and a protrusion 21a formed on the inner surface (axially opposing surface) of the connecting member 21 and adapted to slidably fit into the recess 5b of the spacer 5.

[0037] In addition, the second concave-convex fitting portion consists of a convex portion 21b formed on the outer surface of the connecting member 21 (the axially opposing surface with the lid portion 6b of the housing 6) so as to extend in a direction perpendicular to the convex portion 21a on the inner surface of the connecting member 21, and a concave portion 6e formed on the inner surface of the lid portion 6b of the housing 6 (the axially opposing surface with the connecting member 21) into which the convex portion 21b of the connecting member 21 fits slidably.

[0038] As described above, the spacer 5 is supported non-rotatably but revolvably relative to the housing 6 by this Oldham joint 7. The connecting portion 5a of the spacer 5 and the connecting member 21 are respectively provided with center holes 5c and 21c through which the output shaft 3 passes, and the holes 5c and 21c are both formed to have a size such that they do not interfere with the output shaft 3 when the spacer 5 revolves and the connecting member 21 moves parallel to the axis.

[0039] As shown in Fig. 4, the unlocking mechanism 9 rotates a plurality of operating members 15 screwed to the housing 6 from the state shown in Fig. 1, moves a positioning member 16 integrally connected to the operating members 15 in the axial direction toward the eccentric cam 4, and brings the flange portion of the input shaft 1 into contact with the eccentric cam 4 via a rolling bearing 17 on the radially outer side so as to be capable of transmitting rotation, thereby rotating both the output side member and the input side member consisting of the output shaft 3 and the eccentric cam 4 when a reverse input torque is applied to the output shaft 3 as described below, thereby preventing the output shaft 3 from being locked (releasing the reverse input blocking function). However, normally, as shown in Fig. 1, the operating members 15 and the positioning member 16 are located closer to the motor M than in Fig. 4 (the unlocking mechanism 9 is not in operation), and there is an axial gap between the flange portion of the input shaft 1 and the eccentric cam 4.

[0040] This reverse input cutoff clutch has the above-mentioned configuration, and compared to a conventional lock type clutch incorporating a plurality of small rollers and springs, it has a smaller number of parts and can be easily manufactured and assembled.

[0041] Next, the operation of the reverse input cutoff clutch will be described. First, in normal operation when the unlocking mechanism 9 is not in operation, when a counterclockwise input torque is applied to the input shaft 1 from the state shown in Fig. 3(a), the cam receiver 2 receives a couple of forces from the input shaft 1 and presses the spacer 5 slidably fitted into its eccentric hole 2a, as shown in Fig. 3(b), and the spacer 5 moves upward while being guided by the connecting member 21 constituting the Oldham joint 7, and at the same time, the connecting member 21 moves leftward while being guided by the cover portion 6b of the housing 6, so that the spacer 5 revolves counterclockwise without rotating on its axis relative to the housing 6. Then, with the revolution of the spacer 5, the eccentric cam 4 slidably fitted into the inner periphery of the spacer 5 rotates eccentrically, and the output shaft 3 integral with the eccentric cam 4 rotates.

[0042] On the other hand, when a reverse input torque is applied to the output shaft 3, the eccentric cam 4 integral with the output shaft 3 presses the cam receiver 2 via the spacer 5. However, this pressing force is not a couple force, but a translational force acts on the cam receiver 2 and the spacer 5. As a result, the connecting member 21 of the Oldham joint 7 cannot slide, and the orbital movement of the spacer 5 is restricted.

[0043] At this time, a frictional force acts on the input shaft 1 from the output side member (output shaft 3 and eccentric cam 4) via the sticky oil. However, by adjusting the preload of the two rolling bearings 17, 18 so that the braking force of the braking mechanism 8 is greater than this frictional force, it is possible to prevent the output side member and the input side member from rotating together due to this frictional force.

[0044] That is, in this reverse input cutoff clutch, the output shaft 3 can be reliably locked against reverse input torque by the action of restricting the revolutionary motion of the spacer 5 and the braking force of the braking mechanism 8.

[0045] Here, the input side member rotates smoothly supported by the rolling bearings 17, 18 without sliding against the housing 6 in response to the input torque, and the preload applied to the rolling bearings 17, 18 does not change during use, so the braking force against the rotation of the input side member is kept constant.

[0046] Therefore, this reverse input cut-off clutch is free from the risk of locking failure due to wear of the input side member and housing 6, which is a problem with the structures of Figures 8 and 9 described above, and can perform stable locking operation for a long period of time, and can also be used under conditions in which the input shaft 1 rotates at high speed due to the drive of the motor M.

[0047] In addition, in the event of an emergency or the like when it becomes necessary to move the input side from the output side, as shown in Figure 4, the operating member 15 of the lock release mechanism 9 can be rotated to bring the flange portion of the input shaft 1 into contact with the eccentric cam 4 so that rotation can be transmitted thereto, so that the frictional force acting on the input shaft 1 from the eccentric cam 4 via the sticky oil becomes greater than the braking force of the braking mechanism 8, and a reverse input torque can be applied to the output shaft 3 to rotate the output side member together with the input side member (integrally or with a certain degree of slippage).

[0048] Therefore, for example, if a device incorporating this reverse input cut-off clutch is brought to an emergency stop due to a power outage or the like, the flange portion of the input shaft 1 can be abutted against the eccentric cam 4 by the lock release mechanism 9 as described above, and a reverse input torque can be manually applied to rotate both the output side member and the input side member, thereby moving the device to a position suitable for restarting, and enabling the restart work to be carried out efficiently.

[0049] 5 to 7 show the second embodiment (FIGS. 5 and 7 show the state of use when connected to a motor M). This embodiment is based on the first embodiment, with the configuration of the lock release mechanism and related members changed. The differences from the first embodiment will be described below.

[0050] In the second embodiment, as shown in Fig. 5 (when the unlocking mechanism 22 is not in operation) and Fig. 6, the number of bolts 11 and nuts 12 for connection to the motor M is reduced from four in the first embodiment to three. Although this change is not directly related to the change in the unlocking mechanism, the joint member 10 is also changed to a shape in which the first annular portion 10a and the second annular portion 10b each have three pillar portions 10c that are butted against each other and through which the bolts 11 are passed.

[0051] Among the members related to the lock release mechanism 22, the positioning member 16 has a plurality of protruding portions that protrude radially from the flange of the cylindrical portion 16a, and a circular hole 16d is provided on the axially inner surface of each protruding portion. A plurality of coil-shaped positioning springs 23 have one end abutting against the first annular portion 10a of the joint member 10 and the other end inserted into the circular hole 16d of the positioning member 16, and bias the positioning member 16 toward the motor M (in the axial direction away from the eccentric cam 4). As a result, the positioning member 16 positions the rolling bearings 17 and 18 in a state where it is pressed against the second annular portion 10b of the joint member 10. In addition, the operating member 15 and the male thread portion 6d of the cylindrical portion 6a of the housing 6 in the first embodiment are eliminated.

[0052] As shown in Figure 7, this unlocking mechanism 22 involves inserting a flat unlocking tool 24 with a forked portion at its tip end through window 10d of joint member 10 between positioning member 16 and second annular portion 10b of joint member 10, and using the unlocking tool 24 to press positioning member 16 from the side opposite positioning spring 23, thereby moving positioning member 16 in a direction approaching eccentric cam 4 against the elastic force of positioning spring 23.

[0053] Therefore, in this second embodiment, as in the first embodiment, the flange portion of the input shaft 1 is brought into contact with the eccentric cam 4 in a manner capable of transmitting rotation by the action of the unlocking mechanism 22, and then a reverse input torque is applied to the output shaft 3 to rotate the output side member together with the input side member, thereby preventing the output shaft 3 from being locked.

[0054] In each of the above-described embodiments, in order to ensure that the unlocking mechanism operates reliably, sticky oil is interposed between the axial contact surfaces of the flange portion of the input shaft 1 and the eccentric cam 4 to increase the frictional force when the two members come into contact; however, instead of this, it is also possible to form projections and recesses on the contact surfaces of the two members so that they mesh with each other.

[0055] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, not by the above meaning, and is intended to include all modifications within the scope and meaning equivalent to the claims.

[0056] For example, the swivel support mechanism is not limited to the Oldham joint of each embodiment, but may be any mechanism that has the function of supporting the spacer between the spacer and a fixed member such as a housing so as to be non-rotatable but revolvable. [Explanation of symbols]

[0057] 1 Input shaft 2 Cam holder 2a eccentric hole 3 Output shaft 4 Eccentric Cam 5 Spacer 6 Housing (fixing member) 7 Oldham joint (swivel support mechanism) 8 Braking mechanism 9, 22 Unlocking mechanism 10 Joint material 14, 17, 18 Rolling bearings 15 Operating member 16 Positioning member 20 Preload spring (preload member) 21 Connecting members 23 Positioning spring 24 Unlocking tool Medium motor

Claims

1. the eccentric cam is provided on the input shaft so as to rotate integrally with the input shaft, the eccentric cam having an eccentric axis parallel to the axis of the output shaft, the eccentric cam being provided on the input shaft so as to receive the eccentric cam in a circular eccentric hole having the same eccentric axis as the eccentric axis of the eccentric cam and to rotate integrally with the input shaft, a cylindrical spacer slidably fitted between an inner peripheral surface of the eccentric hole of the cam receiver and an outer peripheral surface of the eccentric cam, a fixed member which rotatably supports the input shaft and the output shaft, a rotation support mechanism which is provided between the spacer and the fixed member and which supports the spacer non-rotatably but revolvably, and a braking mechanism which applies a brake to rotation of an input side member consisting of the input shaft and the cam receiver, When an input torque is applied to the input shaft, a force couple acts on the cam receiver from the input shaft, causing the spacer to revolve, and the eccentric cam and the output shaft to rotate together. When a reverse input torque is applied to the output shaft, a translational force acts on the cam receiver and the spacer from the output shaft via the eccentric cam, and the revolutionary motion of the spacer is restricted, thereby locking the output shaft, The braking mechanism includes two rolling bearings disposed radially between a positioning portion of a positioning member supported by the fixed member, the positioning member positions the radially outer rolling bearing between the positioning member and the input member, A reverse input cut-off clutch characterized in that an unlocking mechanism is provided that prevents the output shaft from locking by moving the positioning member in the axial direction toward the eccentric cam and abutting the input side member against the eccentric cam via the radially outer rolling bearing so as to be able to transmit rotation.

2. 2. The reverse input cut-off clutch according to claim 1, wherein the positioning member is connected to an operating member that is screw-connected to the fixed member so as to be unable to rotate relative to the fixed member and to move integrally therewith in the axial direction, and the positioning member is moved axially by rotating the operating member.

3. 2. The reverse input cut-off clutch according to claim 1, characterized in that the positioning member is urged in the axial direction away from the eccentric cam by a positioning spring arranged between the positioning member and the fixed member, and the positioning member is moved in the direction approaching the eccentric cam by pressing the positioning member from the side opposite the positioning spring with an unlocking tool.

4. 4. A reverse input cut-off clutch as claimed in claim 1, wherein the axial contact surfaces of the input member and the eccentric cam face each other with sticky oil therebetween, or have projections and recesses that mesh with each other.

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