JP7573943B2 - Ratchet Type Clutch - Google Patents

Description

The present invention relates to a torque transmission direction switching ratchet clutch used as a torque transmission device in vehicles, industrial machinery, etc.

Conventionally, there is a clutch using a ratchet mechanism that can switch the torque transmission direction by switching between a state in which rotation in only one or the opposite direction is locked with respect to the rotation direction of the inner ring member relative to the outer ring member or the outer ring member relative to the inner ring member, a state in which rotation in both one and the opposite direction is locked simultaneously, and a state in which rotation in neither one or the opposite direction is locked (see, for example, Patent Documents 1 and 2).

The clutches described in Patent Documents 1 and 2 use an external device such as an actuator to displace an annular member that can change the engagement state of the ratchet mechanism by displacing the member, thereby switching the direction of rotational transmission between the inner and outer rings, i.e., the direction of torque transmission.

Special table 2016-508582 publication JP 2021-038755 A

In recent years, there has been remarkable development in motorized control in vehicles, and the components of various devices installed in vehicles have become more complex, with the weight and installation space of these various devices increasing proportionately. When switching the torque transmission direction with an external device such as an actuator, as in the clutches of Patent Documents 1 and 2, is used as a component of a transmission, there is a risk that the weight of the entire transmission and the installation space required on the vehicle will increase. This could make it difficult to achieve the strict requirements for weight reduction and space saving in recent years.

The present invention was made in consideration of these circumstances, and aims to provide a torque transmission direction switching ratchet clutch that can suppress an increase in the weight of the entire device in which it is incorporated as a component, and an increase in the space required for arranging the device.

In order to solve the above problems, the ratchet clutch according to the present invention comprises:
A first annular member;
a second annular member arranged coaxially with and rotatable relative to the first annular member;
a ratchet mechanism capable of engaging the first annular member with the second annular member so as to transmit torque;
a switching mechanism capable of switching a torque transmission direction between the first annular member and the second annular member,
The ratchet mechanism includes a tooth portion provided on the first annular member;
a first claw member provided on the second annular member and meshing with the tooth portion to lock the relative rotation of the first annular member with respect to the second annular member in a first rotation direction;
a second pawl member provided on the second annular member, paired with the first pawl member, and meshing with the tooth portion to lock the relative rotation of the first annular member with respect to the second annular member in a second rotation direction,
the switching mechanism includes a third annular member that is coaxial with the first and second annular members and is rotatable relative to the first and second annular members;
The third annular member is formed with a limiting portion capable of limiting engagement between the first claw member, the second claw member, or both of the first claw member and the tooth portion by contacting the first claw member, the second claw member, or both of the second claw member, and the tooth portion;
the limiting portion switches between contact and non-contact with one or both of the first claw member and the second claw member by rotation of the third annular member,
the third annular member has a peripheral surface that faces the first claw member and the second claw member in a radial direction,
the limiting portion is a protrusion formed on the circumferential surface and contacting the first claw member and the second claw member to displace the first claw member and the second claw member in a direction away from meshing with the tooth portion,
the protrusion has a circumferential length longer than a circumferential length between the tips of the first claw member and the second claw member that form a pair,
The apex of the protrusion is located radially on the non-meshing direction side of the apex of the tooth .

The present invention provides a torque transmission direction switching ratchet clutch that can suppress an increase in the overall weight of the device in which it is incorporated as a component and an increase in the space required for arranging the device.

FIG. 1 is a front view, partially cut away, of a torque transmission direction switching ratchet clutch according to an embodiment of the present invention as viewed from the axial direction. FIG. 2 is a cross-sectional view taken along line 2-2 of FIG. FIG. 3 is a partial enlarged view of a torque transmission direction switching ratchet clutch, and FIGS. 3(a), 3(b), 3(c) and 3(d) show a first state, a second state, a third state and a fourth state, respectively, of the torque transmission direction switching ratchet clutch.

The torque transmission direction switching ratchet clutch according to an embodiment of the present invention will be described below with reference to the drawings. The torque transmission direction switching ratchet clutch according to this embodiment will be described as an example used as a component part of a vehicle transmission. In the following description, the torque transmission direction switching ratchet clutch may be abbreviated to "ratchet clutch."

First, the directions related to the torque transmission direction switching ratchet clutch in this embodiment are defined. In this embodiment, the "center axis C" refers to the center axis of the ratchet clutch, i.e., the center axis of the outer ring and the inner ring, and the axial direction, radial direction, and circumferential direction refer to the axial direction, radial direction, and circumferential direction relative to the center axis C. Regarding the axial direction, in Figs. 1 and 3, the direction toward the front of the paper is one axial direction, and the direction toward the back of the paper is the other axial direction, and in Fig. 2, the left side of the paper is one axial direction, and the right side of the paper is the other axial direction. Regarding the circumferential direction, in Figs. 1 and 3, the direction rotating clockwise toward the paper is one circumferential direction, and the direction rotating counterclockwise toward the paper is the other circumferential direction.

For the sake of convenience, the direction of rotation of a ratchet clutch will be described as the direction of rotation of the inner ring relative to the outer ring, but the rotation of the outer ring and the rotation of the inner ring are relative to each other. For example, if the inner ring can rotate clockwise, the outer ring can also rotate counterclockwise. Even if the inner ring and the outer ring rotate in the same direction, if the rotational speeds of the outer ring and the inner ring are different, the outer ring and the inner ring can be said to rotate in one direction relative to each other.

FIG. 1 is a front view, partially cut away, of a torque transmission direction switching ratchet clutch according to an embodiment of the present invention as viewed from the axial direction.
FIG. 2 is a cross-sectional view taken along line 2-2 of FIG.

The torque transmission direction switching ratchet clutch 1 according to this embodiment has an annular outer ring 3, an annular inner ring 5 spaced radially inward from the outer ring 3, coaxial with the central axis C of the outer ring 3 and rotatable relative to the outer ring 3, and a torque transmission mechanism that enables torque transmission between the outer ring 3 and the inner ring 5. The torque transmission mechanism in this embodiment is a ratchet mechanism.

The outer ring 3 is composed of a cylindrical main body 17 having a predetermined length in the axial direction, and an annular portion 19 that protrudes radially inward from the other axial side portion of the main body 17 and extends around the entire circumference in the circumferential direction. The main body 17 and the annular portion 19 on the inner circumference side are integrally formed. A plurality of claw mechanisms, which will be described later, are held in the annular portion 19. A plurality of protrusions 21 that protrude radially outward and extend in the axial direction are provided at predetermined intervals in the circumferential direction on the outer peripheral surface of the main body 17 of the outer ring 3. These protrusions 21 are fitted into fitting portions of an outer member (not shown), thereby fixing the outer ring 3 to the outer member so as not to rotate relative to the outer member.
In the following description, for convenience, the portion of the main body 17 that extends axially further to one side than the annular portion 19 in the outer ring 3 will be referred to as the "cylindrical portion 23" of the outer ring 3 (see FIG. 2).

As shown in FIG. 1, the inner peripheral portion of the annular portion 19 of the outer ring 3 is provided with a first claw member 31 and a second claw member 37 that is adjacent to the other circumferential side of the first claw member 31 and pairs with the first claw member 31. The first claw member 31 and the second claw member 37 constitute a claw mechanism. That is, the annular portion 19 of the outer ring 3 is provided with a claw mechanism including the first claw member 31 and the second claw member 37 that are arranged in sequence from one circumferential side to the other circumferential side when viewed from one axial side. A plurality of such claw mechanisms are provided at predetermined intervals in the circumferential direction on the annular portion 19 of the outer ring 3. The first claw member 31 has a claw portion 29 extending from the cylindrical portion 27 toward one circumferential side, and the second claw member 37 has a claw portion 35 extending from the cylindrical portion 33 toward the other circumferential side. In this embodiment, three claw mechanisms are provided at equal intervals in the circumferential direction, but only one claw mechanism is shown in FIG. 1.

The inner ring 5 is disposed radially inward of the annular portion 19 of the outer ring 3. A large number of teeth 13 are formed on the outer periphery of the inner ring 5 at equal intervals around the entire circumference. Each tooth 13 protrudes radially outward and extends in the direction of the central axis C. The inner circumferential surface of the annular portion 19 of the outer ring 3 and the outer periphery of the inner ring 5, i.e., the teeth 13, face each other radially across a predetermined space. The teeth 13 form ratchet teeth with which the first pawl member 31 and the second pawl member 37 mesh. Specifically, the side surface on the other circumferential side of each tooth 13 forms a first meshing portion 13a that meshes with the first pawl member 31, and the side surface on one circumferential side of each tooth 13 forms a second meshing portion 13b that meshes with the second pawl member 37.

The inner peripheral surface of the inner ring 5 is provided with splines 11 around the entire circumference. An output or input shaft member (not shown) is spline-fitted to the inner peripheral side of the inner ring 5 via the splines 11.

The first claw member 31 is held by a holding portion 39 formed on the inner peripheral portion of the annular portion 19 of the outer ring 3 so that the claw portion 29 can swing radially around the cylindrical portion 27. The holding portion 39 is a recess that opens on one axial end face and the inner peripheral surface of the annular portion 19. The holding portion 39 is provided with a coil spring 41 that constantly biases the claw portion 29 of the first claw member 31 radially inward, i.e., toward the outer peripheral surface of the inner ring 5. For example, in FIG. 1, when the inner ring 5 rotates counterclockwise, the claw portion 29 of the first claw member 31 meshes with the first meshing portion 13a of the tooth portion 13 of the inner ring 5. On the other hand, when the inner ring 5 rotates clockwise, the claw portion 29 of the first claw member 31 is pushed radially outward by the tooth portion 13 of the inner ring 5 against the biasing force of the spring 41, allowing the inner ring 5 to rotate. As a result, the first claw member 31 locks the rotation of the inner ring 5 in the other circumferential direction, while allowing the inner ring 5 to rotate in one circumferential direction.

The second claw member 37 is held by a holding portion 43 formed on the inner peripheral portion of the annular portion 19 of the outer ring 3 so that the claw portion 35 can swing radially around the cylindrical portion 33. The holding portion 43 is a recess that opens on one axial end face and the inner peripheral surface of the annular portion 19. The holding portion 43 is provided with a coil spring 45 that constantly biases the claw portion 35 of the second claw member 37 radially inward, i.e., toward the outer peripheral surface of the inner ring 5. For example, in FIG. 1, when the inner ring 5 rotates clockwise, the claw portion 35 of the second claw member 37 meshes with the second meshing portion 13b of the tooth portion 13 of the inner ring 5. On the other hand, when the inner ring 5 rotates counterclockwise, the claw portion 35 of the second claw member 37 is pushed radially outward by the tooth portion 13 of the inner ring 5 against the biasing force of the spring 45, allowing the inner ring 5 to rotate. As a result, the second pawl member 37 locks the rotation of the inner ring 5 in one circumferential direction and allows the rotation of the inner ring 5 in the other circumferential direction.
In this way, the first pawl member 31 and the second pawl member 37 held by the holding portions 39, 43 of the outer ring 3, the springs 41, 45, and the inner ring 5 on which the teeth portion 13 is formed form a ratchet mechanism.

An annular plate 51 is arranged coaxially with the outer ring 3 on the inner peripheral side of the cylindrical portion 23 of the outer ring 3. The annular plate 51 faces the axial end face of the annular portion 19 of the outer ring 3, the axial end faces of the first and second claw members 31 and 37 that form a plurality of pairs, and the axial end of the inner ring 5. The annular plate 51 is held in the cylindrical portion 23 of the outer ring 3 so as to be rotatable relative to the outer ring 3 and the inner ring 5 about the central axis C. A circumferential groove 53 is formed in the inner peripheral surface of the cylindrical portion 23 of the outer ring 3 adjacent to the axial end of the annular plate 51. A retaining ring 55 is fitted into the circumferential groove 53. The axial movement of the annular plate 51 is restricted by the axial end face of the annular portion 19 of the outer ring 3 and the retaining ring 55.

A thick portion 57 that protrudes to the other axial direction is formed around the entire circumference of the inner diameter side of the annular plate 51. The thick portion 57 is located radially inward of the annular portion 19 of the outer ring 3, that is, radially inward of the pair of first and second claw members 31, 37. The thick portion 57 also protrudes to the other axial direction to an axial position corresponding to the axial middle portion of the first and second claw members 31, 37. The end face on the other axial side of the thick portion 57 axially faces the end of one axial side of the inner ring 5. With this configuration, the outer peripheral surface of the thick portion 57 faces the axial one side portion of the inner peripheral surface of the annular portion 19 of the outer ring 3, the axial one side portion of the inner diameter side surface of the first claw member 31, and the axial one side portion of the inner diameter side surface of the second claw member 37 through a predetermined space.

As shown in FIG. 1, the outer peripheral surface of the thick portion 57 is provided with a plurality of convex portions 59 at predetermined intervals in the circumferential direction, which protrude radially outward and extend over a predetermined range in the circumferential direction. In this embodiment, three convex portions 59 are provided at equal intervals in the circumferential direction in correspondence with the claw mechanism portion. The top of the convex portion 59 is located slightly radially outward from the top of the tooth portion 13 of the inner ring 3, extends along the inner peripheral surface of the annular portion 19 of the outer ring 3, and faces the inner peripheral surface of the annular portion 19 in the radial direction with a small gap therebetween. In other words, the top of the convex portion 59 is not in contact with the inner peripheral surface of the annular portion 19 of the outer ring 3. Both circumferential ends of the top of the convex portion 59 are smoothly continuous with the outer peripheral surface of the thick portion 57 via the inclined surfaces 61, respectively. With this configuration, the first claw member 31 and the second claw member 37 are smoothly pushed up from the outer circumferential surface of the thick portion 57 to the top of the protrusion 59 by the rotation of the annular plate 51.

When the top of the protrusion 59 is positioned on the inner diameter side of the first claw member 31 due to the rotation of the annular plate 51, it comes into contact with the inner diameter side surface of the first claw member 31 and pushes and holds the inner diameter side surface of the first claw member 31 on the outer diameter side of the toothed portion 13 of the inner ring 5. As a result, the protrusion 59 limits the engagement between the first claw member 31 and the toothed portion 13. Similarly, when the top of the protrusion 59 is positioned on the inner diameter side of the second claw member 37, it comes into contact with the inner diameter side surface of the second claw member 37 and pushes and holds the inner diameter side surface of the second claw member 37 on the outer diameter side of the toothed portion 13 of the inner ring 5. As a result, the protrusion 59 limits the engagement between the second claw member 37 and the toothed portion 13.

The annular plate 51 changes the circumferential position of the protrusion 59 of the thick portion 57 relative to the pawl mechanism by rotating in one circumferential direction or the other. This changes the combined state of contact or non-contact of the protrusion 59 with the pawl mechanism, i.e., the pair of the first and second pawl members 31 and 37. Specifically, the annular plate 51 switches between four combined states of contact or non-contact of the protrusion 59 with the pawl mechanism, thereby switching the torque transmission direction of the ratchet clutch 1. In other words, the annular plate 51 constitutes a torque transmission direction switching mechanism. These four combined states and the torque transmission direction of the ratchet clutch 1 will be described later.

The annular plate 51 is connected to a drive mechanism (not shown) in a transmission (not shown) in which the ratchet clutch 1 is incorporated, and is rotated by the drive mechanism. The drive mechanism in the transmission to which the annular plate 51 is connected can be, for example, a linear motion mechanism, a rotary mechanism, or a combination of a linear motion mechanism and a rotary mechanism. Such a drive mechanism can be, for example, a worm gear (not shown) for switching gears in the transmission. As shown in FIG. 1, a plurality of plate fixing holes 63 are provided on one axial end face of the annular plate 51, and, for example, a worm wheel (not shown) of a worm gear (not shown) is connected to the annular plate 51 using these plate fixing holes 63. That is, the annular plate 51 is fixed concentrically to the worm wheel (not shown). In this way, the annular plate 51 can be controlled to rotate in conjunction with, for example, a worm gear (not shown) in the transmission.

In this way, the annular plate 51 is connected to a rotating mechanism (not shown) in a transmission (not shown) in which the ratchet clutch 1 is incorporated, and is driven and controlled by the rotating mechanism, so there is no need to provide a separate device outside the transmission for driving the annular plate 51.

Next, the operation of the ratchet clutch 1 will be described.
Figure 3 is a partially enlarged view of the ratchet clutch 1, and Figures 3(a), 3(b), 3(c), and 3(d) respectively show a first state, a second state, a third state, and a fourth state of the ratchet clutch 1. Each state of the ratchet clutch 1 will be described below. Note that the following description is for one pawl mechanism, but the other pawl mechanisms are similar.

The first state of the ratchet clutch 1, that is, the first combination state of the contact or non-contact of the radial protrusion 59 of the annular plate 51 with the claw mechanism, is a state in which the protrusion 59 does not contact either the first claw member 31 or the second claw member 37 and faces the inner circumferential surface of the annular portion 19 of the outer ring 3, as shown in FIG. 3(a). In other words, the first claw member 31 and the second claw member 37 are located between the protrusions 59 adjacent to each other in the circumferential direction and face the outer circumferential surface of the thick portion 57 of the annular plate 51 in the radial direction. In FIG. 3(a), the inclined surface 61 at one circumferential end of the protrusion 59 is located near the other circumferential side of the tip of the claw portion 35 of the second claw member 37. In this state, the first claw member 31 and the second claw member 37 are engaged with the teeth 13 of the inner ring 5 by the biasing forces of the springs 41 and 45, respectively. Therefore, in this state, the inner ring 5 is locked against rotation in either one circumferential direction or the other circumferential direction relative to the outer ring 3. In other words, if the inner ring 5 is the input side, the inner ring 5 is locked against the outer ring 3 in both one circumferential direction and the other circumferential direction.

When the annular plate 51 rotates a predetermined angle in one circumferential direction from the first state shown in FIG. 3(a), the claw portion 35 of the second claw member 37 rides up onto the top of the convex portion 59 via the slope 61 on one circumferential side of the convex portion 59, and faces the top of the convex portion 59 in the radial direction, and the ratchet clutch 1 switches to the second state shown in FIG. 3(b).

The second state of the ratchet clutch 1, that is, the second combination state of the contact or non-contact of the protrusion 59 with the claw mechanism, is a state in which the protrusion 59 contacts the inner diameter side surface of the second claw member 37 and does not contact the first claw member 31, as shown in FIG. 3(b). In FIG. 3(b), the inclined surface 61 at one circumferential end of the protrusion 59 is located in the middle between the pair of the first claw member 31 and the second claw member 37. In this state, the radial protrusion 59 contacts the second claw member 37 with the spring 45 compressed, and pushes up and holds the inner diameter side surface of the second claw member 37 to the outer diameter side beyond the toothed portion 13 of the inner ring 5, limiting the engagement between the second claw member 37 and the toothed portion 13 of the inner ring 5. Meanwhile, the first claw member 31 is engaged with the toothed portion 13 of the inner ring 5 by the biasing force of the spring 41. Therefore, in this state, the inner ring 5 can rotate in one circumferential direction relative to the outer ring 3, and rotation in the other circumferential direction is locked. In other words, if the inner ring 5 is the input side, torque is transmitted from the inner ring 5 to the outer ring 3 in the other circumferential direction, but torque is not transmitted in one circumferential direction.

When the annular plate 51 rotates a predetermined angle in one circumferential direction from the second state shown in FIG. 3(b), in addition to the claw portion 35 of the second claw member 37, the claw portion 29 of the first claw member 31 rides up onto the top of the convex portion 59 via the slope 61 on one circumferential side of the convex portion 59, and faces the top of the convex portion 59 in the radial direction, and the ratchet clutch 1 switches to the third state shown in FIG. 3(c).

3(c), the third state of the ratchet clutch 1, that is, the third combination state of the contact or non-contact of the protrusion 59 with the pawl mechanism, is a state in which the protrusion 59 is in contact with the inner diameter side surface of the first pawl member 31 and the inner diameter side surface of the second pawl member 37. In this state, the inclined surface 61 at one circumferential end of the protrusion 59 is located on one circumferential side of the tip of the pawl portion 29 of the first pawl member 31, and the inclined surface 61 at the other circumferential end of the protrusion 59 is located on the other circumferential side of the tip of the pawl portion 35 of the second pawl member 37. In this way, the apex of the protrusion 59 has a circumferential length that is longer than the circumferential length of the claw mechanism, i.e., the circumferential length from one circumferential end of the first claw member 31 to the other circumferential end of the paired second claw member 37, specifically, the circumferential length from the tip of the claw portion 29 of the first claw member 31 to the tip of the claw portion 35 of the paired second claw member 37.

In this state, the protrusion 59 contacts the first claw member 31 with the spring 41 compressed, pushing up and holding the inner diameter side surface of the first claw member 31 on the outer diameter side of the teeth 13 of the inner ring 5, restricting the engagement between the first claw member 31 and the teeth 13 of the inner ring 5, and contacts the second claw member 37 with the spring 45 compressed, pushing up and holding the inner diameter side surface of the second claw member 37 on the outer diameter side of the teeth 13 of the inner ring 5, restricting the engagement between the second claw member 37 and the teeth 13 of the inner ring 5. Therefore, in this state, the inner ring 5 is not locked in either the rotation in one circumferential direction or the rotation in the other circumferential direction relative to the outer ring 3, and can rotate in either the one circumferential direction or the other circumferential direction. In other words, if the inner ring 5 is the input side, torque is not transmitted from the inner ring 5 to the outer ring 3 in either the one circumferential direction or the other circumferential direction.

When the annular plate 51 rotates a predetermined angle in one circumferential direction from the third state shown in FIG. 3(c), the claw portion 35 of the second claw member 37 is displaced from a position radially facing the top of the protrusion 59 to a position radially facing the outer circumferential surface of the thick portion 57 via the inclined surface 61 on the other circumferential side of the protrusion 59, and the ratchet clutch 1 switches to the fourth state shown in FIG. 3(d).

The fourth state of the ratchet clutch 1, that is, the fourth combination state of the contact or non-contact of the protrusion 59 with the claw mechanism, is a state in which the protrusion 59 contacts the inner diameter side surface of the first claw member 31 and does not contact the paired second claw member 37, as shown in FIG. 3(d). In FIG. 3(d), the inclined surface 61 at the other circumferential end of the protrusion 59 is located in the middle between the paired first claw member 31 and second claw member 37. In this state, the protrusion 59 contacts the first claw member 31 with the spring 41 compressed, and pushes up and holds the inner diameter side surface of the first claw member 31 to the outer diameter side beyond the toothed portion 13 of the inner ring 5, limiting the engagement between the first claw member 31 and the toothed portion 13 of the inner ring 5. Meanwhile, the second claw member 37 is engaged with the toothed portion 13 of the inner ring 5 by the biasing force of the spring 45. Therefore, in this state, the inner ring 5 can rotate in the other circumferential direction relative to the outer ring 3, and rotation in one circumferential direction is locked. In other words, if the inner ring 5 is the input side, torque is transmitted from the inner ring 5 to the outer ring 3 in one circumferential direction, but not in the other circumferential direction.

In this way, the ratchet clutch 1 of this embodiment switches from the first state to the fourth state each time the annular plate 51 rotates a predetermined angle in one circumferential direction. That is, the torque transmission direction of the ratchet clutch 1 switches. When the ratchet clutch 1 rotates a predetermined angle in the same circumferential direction from the fourth state, it returns to the first state. In other words, the annular plate 51 can rotate in only one circumferential direction, not just repeatedly rotate in one and the other circumferential directions as in the past, so that the torque transmission direction can be arbitrarily set. And in the ratchet clutch 1 of this embodiment, as described above, the annular plate 51 is driven and controlled by a drive mechanism (not shown) such as a linear mechanism or a rotation mechanism in the transmission in which the ratchet clutch 1 is incorporated, so there is no need to provide a separate device for driving the annular plate 51 outside the transmission. Therefore, according to this embodiment, it is possible to suppress an increase in the weight of the entire device in which the ratchet clutch 1 is incorporated as a component and an increase in the space required for arranging the device. If the device in which the ratchet clutch 1 is incorporated as a component, as in this embodiment, is a vehicle transmission, it is possible to prevent an increase in the weight of the entire transmission and an increase in the installation space required in the vehicle.

The ratchet-type clutch 1 of the present invention is not limited to the above embodiment, and can be modified. For example, the pawl mechanism may be provided on the inner ring side, and the teeth that mesh with the pawl mechanism may be provided on the inner peripheral surface of the outer ring. In this case, the annular plate, which is the torque transmission direction switching mechanism, has an inner peripheral surface that is disposed radially outward of the pawl mechanism, and a protrusion that limits the meshing between the pawl member of the pawl mechanism and the teeth is provided on the inner peripheral surface of the annular plate. In addition, although three pawl mechanisms are provided in the above embodiment, the number of pawl mechanisms can be changed as appropriate depending on the torque capacity to be transmitted. Furthermore, the multiple pawl mechanisms may or may not be provided at equal intervals in the circumferential direction.

REFERENCE SIGNS LIST 1 Ratchet clutch 3 Outer ring 5 Inner ring 19 Annular portion 23 Cylindrical portion 31 First claw member 37 Second claw member 51 Annular plate 55 Retaining ring 59 Convex portion 61 Slope 63 Plate fixing hole

Claims (3)

A first annular member;
a second annular member arranged coaxially with and rotatable relative to the first annular member;
a ratchet mechanism capable of engaging the first annular member with the second annular member so as to transmit torque;
a switching mechanism capable of switching a torque transmission direction between the first annular member and the second annular member,
The ratchet mechanism includes a tooth portion provided on the first annular member;
a first claw member provided on the second annular member and meshing with the tooth portion to lock the relative rotation of the first annular member with respect to the second annular member in a first rotation direction;
a second pawl member provided on the second annular member, paired with the first pawl member, and meshing with the tooth portion to lock the relative rotation of the first annular member with respect to the second annular member in a second rotation direction,
the switching mechanism includes a third annular member that is coaxial with the first and second annular members and is rotatable relative to the first and second annular members;
The third annular member is formed with a limiting portion capable of limiting engagement between the first claw member, the second claw member, or both of the first claw member and the tooth portion by contacting the first claw member, the second claw member, or both of the second claw member, and the tooth portion;
the limiting portion switches between contact and non-contact with one or both of the first claw member and the second claw member by rotation of the third annular member,
the third annular member has a peripheral surface that faces the first claw member and the second claw member in a radial direction,
the limiting portion is a protrusion formed on the circumferential surface and contacting the first claw member and the second claw member to displace the first claw member and the second claw member in a direction away from meshing with the tooth portion,
the protrusion has a circumferential length longer than a circumferential length between the tips of the first claw member and the second claw member that form a pair,
A ratchet clutch , characterized in that the apex of the convex portion is located radially on the non-engagement direction side of the apex of the tooth portion . A plurality of pairs of the first claw members and the second claw members are provided in a circumferential direction,
2. The ratchet clutch according to claim 1 , wherein a plurality of said protrusions are provided corresponding to the number of pairs of said first pawl members and said second pawl members. 3. The ratchet clutch according to claim 1, wherein the third annular member is driven by a drive mechanism of an apparatus in which the ratchet clutch is incorporated as a component part.

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