Clutch unit

Abstract

Provided is a clutch unit 1 including: an input-side clutch 10 that controls the transmission and blocking of torque which is input through a lever operation; an output-side clutch 20 that, when no lever operation is performed, is set to a locked state that restricts the rotation of an output shaft 2 and blocks reverse input torque which is input to the output shaft 2; and a lock mechanism 30 that restricts the rotation of the output shaft 2 at an axial position different from that of the output-side clutch 20. The lock mechanism 30 restricts the rotation of the output shaft 2 by meshing external teeth 31b of a first lock element 31 that rotates integrally with the output shaft 2 with internal teeth 32a of a second lock element 32 that is restricted from rotating about the axis X of the output shaft 2, and releases the meshing state of the external teeth 31b and the internal teeth 32a when the second gear 32 is moved in the axial direction through a lever operation. The tooth width L2 of the internal teeth 32a of the second lock element 32 is set to be smaller than the tooth width L1 of the external teeth 31b of the first lock element 31.

Description

Clutch unit

[0001] The present invention relates to a clutch unit.

[0002] For example, Patent Document 1 listed below describes a clutch unit that is incorporated into a seat lifter that adjusts the seat height of an automobile seat, and that includes an input clutch that controls the transmission and interruption of torque input by rotating an operating lever (hereinafter simply referred to as "lever operation"), an output clutch consisting of a reverse input interruption clutch, and an output shaft onto which the input and output clutches are fitted, and in which torque input from the input clutch to the output clutch releases the locked state (reverse input interruption state) of the output clutch, causing the output shaft to rotate around its axis.

[0003] More specifically, in the output clutch of the clutch unit, when no torque is input to the input clutch through lever operation, the rollers, which serve as engaging elements disposed in a wedge gap between the outer peripheral surface of an inner ring that rotates integrally with the output shaft and the inner peripheral surface of a stationary member (outer ring) whose rotation is restricted, mesh with both the inner ring and the outer ring (engaging circumferentially with both the inner ring and the outer ring), thereby restricting relative rotation between the inner ring and the outer ring, i.e., rotation of the output shaft. In this locked state, reverse input torque input to the output shaft is not transmitted to the input clutch because rotation of the output shaft is restricted. On the other hand, when torque is input from the input clutch to the output clutch through lever operation, the rollers are pushed out of the wedge gap, thereby entering an unlocked state in which rotation of the inner ring relative to the outer ring is permitted. In the unlocked state, torque input from the input clutch is transmitted to the output shaft via the inner ring, causing the output shaft to rotate.

[0004] JP 2017-109698 A

[0005] As described above, the locked state of the output clutch of the clutch unit is achieved by the roller disposed in the wedge gap between the inner and outer rings engaging with both the inner and outer rings. However, slight slippage may occur between the roller and the inner and / or outer ring, potentially causing the output shaft to rotate unintentionally. If such slight slippage occurs in a driver's seat lifter, the seat height of the driver's seat gradually drops, making it impossible to maintain an appropriate driving position and causing driving problems. Therefore, it is necessary to strengthen the restriction on output shaft rotation when the operating lever is not being operated.

[0006] Therefore, the main object of the present invention is to strengthen the rotation restriction of the output shaft when the operating lever is not operated in a clutch unit that includes an input side clutch that controls the transmission and interruption of torque input by lever operation, and an output side clutch that consists of a reverse input interruption clutch that is released from a locked state that restricts the rotation of the output shaft as torque is input to the input side clutch, allowing the torque to be transmitted to the output shaft.

[0007] The first invention of the present application, which was devised to achieve the above object, comprises an input side clutch that controls the transmission and interruption of torque input by lever operation; an output side clutch that is in a locked state to interrupt reverse input torque input to the output shaft when the lever is not operated; and a locking mechanism that restricts rotation of the output shaft at an axial position different from the output side clutch, wherein the locking mechanism restricts rotation of the output shaft by meshing the external teeth of a first locking element that rotates integrally with the output shaft with the internal teeth of a second locking element whose rotation around the axis of the output shaft is restricted, and the meshed state of the external teeth and internal teeth is released when the second locking element moves in the axial direction of the output shaft in response to lever operation, and is characterized in that the tooth width of the internal teeth of the second locking element is smaller than the tooth width of the external teeth of the first locking element.

[0008] In the clutch unit according to the first aspect of the present invention having the above configuration, a locking mechanism is additionally provided that restricts rotation of the output shaft at a different axial position from the output clutch when there is no lever operation (or associated torque input to the input clutch). This strengthens the restriction on rotation of the output shaft when the operating lever is not being operated, effectively reducing the possibility of the output clutch being unintentionally released from its locked state (unintentional rotation of the output shaft).

[0009] The locking mechanism restricts rotation of the output shaft by meshing (engaging circumferentially around the output shaft) the external teeth of a first locking element, which rotates integrally with the output shaft, with the internal teeth of a second locking element, whose rotation about the output shaft is restricted. The second locking element can be disengaged from the meshed state by axially moving the second locking element in response to lever operation. By making the tooth width (axial length) of the internal teeth of the second locking element, which moves axially in response to lever operation, smaller than the tooth width of the external teeth of the first locking element, which does not move axially, the relative axial movement of the external teeth and the internal teeth required to disengage the meshed state can be reduced. This reduces the amount of operation of the operating lever required to release the meshed state of the first locking element and the second locking element of the locking mechanism, and thus the locked state of the output clutch, thereby enabling the output shaft to rotate with good responsiveness when the lever is operated. The first locking element may be, for example, an external gear having a plurality of teeth (external teeth) formed at equal intervals around the circumference on its outer circumferential surface, and the second locking element may be, for example, an internal gear having a plurality of teeth (internal teeth) formed at equal intervals around the circumference on its inner circumferential surface that can mesh with the external teeth; however, each locking element may be something other than the above-mentioned gears as long as it has teeth that can mesh with the mating locking element.

[0010] In the clutch unit according to the first aspect of the present invention, the external teeth can be formed by stamping (into a predetermined shape) the metal plate that forms the base material of the first locking element, and the internal teeth can be formed by stamping (into a predetermined shape) the metal plate that forms the base material of the second locking element. This reduces the cost of a clutch unit that would otherwise require an additional locking mechanism that restricts rotation of the output shaft by meshing the locking elements together. In this case, the first locking element and the second locking element are preferably arranged so that the punched ends of the external teeth and internal teeth are flush with each other when the lever is not operated. This ensures sufficient meshing between the external teeth and internal teeth, thereby appropriately strengthening the restriction on rotation of the output shaft.

[0011] In the clutch unit according to the first aspect of the present invention, the first locking element can have an integral cylindrical fixing portion that is fixed to the outer peripheral surface of the output shaft, and this fixing portion does not contact any member other than the first locking element in the axial direction of the output shaft. This allows for flexibility in selecting the position when fixing the first locking element to the output shaft, thereby improving the ease of assembly of the locking mechanism and, ultimately, the clutch unit.

[0012] Furthermore, the second invention of the present application, which was devised to achieve the above object, comprises an input side clutch that controls the transmission and interruption of torque input by lever operation; an output side clutch that is in a locked state to interrupt reverse input torque input to the output shaft when the lever is not operated; and a locking mechanism that restricts rotation of the output shaft at an axial position different from the output side clutch, wherein the locking mechanism restricts rotation of the output shaft by meshing external teeth of a first locking element that rotates integrally with the output shaft with internal teeth of a second locking element whose rotation around the axis of the output shaft is restricted, and wherein the first locking element and the second locking element move relatively in the axial direction of the output shaft in response to lever operation, thereby releasing the meshed state of the external teeth and internal teeth, and wherein the external teeth and internal teeth mesh via a radial gap with a gap width of 0.2 to 0.4 mm.

[0013] In the clutch unit according to the second aspect of the present invention having the above configuration, since a locking mechanism that restricts rotation of the output shaft at an axial position different from that of the output clutch when the lever is not operated is additionally provided, the restriction on rotation of the output shaft can be strengthened, effectively reducing the possibility of unintended rotation of the output shaft. In particular, in the locking mechanism having the above configuration, if the external teeth and internal teeth are meshed with each other via a radial gap with a gap width within a range of 0.2 to 0.4 mm, the function of strengthening the restriction on rotation of the output shaft can be appropriately exhibited.

[0014] In the clutch unit according to the second aspect of the present invention, the tooth width (axial dimension) of the external teeth is preferably larger than the tooth width of the internal teeth.

[0015] In addition, in the clutch unit according to the second aspect of the present invention, it is preferable that the external teeth and internal teeth are engaged with each other via a circumferential gap, and in this case, it is preferable that the width of the circumferential gap is equal to or smaller than the width of the radial gap.

[0016] In the clutch unit according to the second aspect of the present invention, the first and second locking elements can be stamped from a metal plate. This reduces the cost of a clutch unit that would otherwise require a locking mechanism. In this case, both locking elements have shear surfaces whose thickness-wise lengths of the metal plate are 70% or more of the thickness of the metal plate. This increases the meshing accuracy of the first and second locking elements. For the same reasons, it is preferable that the external teeth of the first locking element and the internal teeth of the second locking element, which are stamped from a metal plate, have a sag of 40% or less of the thickness of the metal plate at the tooth tips and a sag of 20% or less of the thickness of the metal plate in the region excluding the tooth tips.

[0017] In the clutch units according to the first and second inventions having the above configuration, the output side clutch constituting the clutch unit can be, for example, one that includes a stationary member whose rotation around the central axis of the output shaft is restricted, and a roller arranged in a wedge gap formed between a plurality of cam surfaces provided on the output shaft and the inner surface of the stationary member, and that enters a locked state when the roller engages with the output shaft and the stationary member in the rotational direction of the output shaft.

[0018] From the above, according to the first invention of the present application, in a clutch unit equipped with an input side clutch that controls the transmission and interruption of torque input by lever operation, and an output side clutch consisting of a reverse input interruption clutch, it is possible to strengthen the rotation restriction of the output shaft when the operating lever is not operated, and yet it is possible to make the output shaft rotatable with good responsiveness when the lever is operated.

[0019] In addition, according to the second invention of the present application, in a clutch unit that includes an input side clutch that controls the transmission and interruption of torque input by lever operation, and an output side clutch consisting of a reverse input interruption clutch, it is possible to strengthen the rotation regulation of the output shaft.

[0020] 1 is a schematic longitudinal cross-sectional view of a clutch unit according to an embodiment of the first invention, showing the operation lever in a neutral position (when the lever is not being operated); FIG. 1 is a cross-sectional view taken along arrow A in FIG. 1; FIG. 1 is a cross-sectional view taken along arrow B in FIG. 1; FIG. 1 is a cross-sectional view taken along arrow A in FIG. 1 of the clutch unit when the lever is being operated; FIG. 1 is a cross-sectional view taken along arrow B in FIG. 1 of the clutch unit when the lever is being operated; FIG. 1 is an exploded perspective view of a portion of the clutch unit shown in FIG. 1; FIG. 1 is a plan view and a side view of the lock mechanism when positioned in a locked position; FIG. 1 is a plan view and a side view of the lock mechanism when positioned in an unlocked position; FIG. 1 is a schematic longitudinal cross-sectional view of the lock mechanism when the lever is being operated; FIG. 1 is a perspective view conceptually showing the cross-sectional state of a punched metal plate; FIG. 1 is an enlarged view of a main part of FIG. 1; FIG. 1 is an enlarged view of a main part of a clutch unit that does not employ the configuration of the first invention; FIG. 12 is a schematic longitudinal cross-sectional view of a clutch unit according to an embodiment of the second invention, showing the operation lever when the lever is not present; FIG. 13 is a cross-sectional view taken along arrow A in FIG. 12; FIG. 13 is a cross-sectional view taken along arrow B in FIG. 12 of the clutch unit when the lever is being operated; Fig. 21A is an exploded perspective view of a portion of the clutch unit shown in Fig. 12. Fig. 21B is a plan view and a side view of the locking mechanism positioned at a locked position. Fig. 21C is a plan view and a side view of the locking mechanism positioned at an unlocked position. Fig. 21D is a schematic vertical cross-sectional view of the locking mechanism when the lever is operated. Fig. 21E is a perspective view conceptually showing the state of the processed surface of a metal plate that has been subjected to press punching. Fig. 21F is a schematic cross-sectional view of the metal plate shown in Fig. 21A.

[0021] A first embodiment of the present invention will be described below with reference to FIGS.

[0022] FIG. 1 is a schematic longitudinal cross-sectional view of a clutch unit 1 according to a first embodiment of the present invention, showing the state when an operating lever is in a neutral position (when no lever is being operated). The clutch unit 1 is used, for example, in a seat lifter for adjusting the height of a vehicle seat. The clutch unit 1 includes an output shaft 2 rotatably mounted about an axis X, a housing 3, an operating lever 4, an input clutch 10, an output clutch 20, and a mechanical locking mechanism 30. In the following description, the terms "axial direction," "radial direction," and "circumferential direction" used to indicate directionality refer to a direction parallel to the axis X of the output shaft 2, a radial direction of a circle centered on the axis X, and a circumferential direction of a circle centered on the axis X, respectively. Furthermore, unless otherwise specified, "rotation" in the following description refers to rotation about the axis X of the output shaft 2.

[0023] The output shaft 2 includes a small-diameter portion 2a having a cylindrical outer peripheral surface with a constant diameter, a spline portion 2b on which a spline (male spline) is formed, a large-diameter portion 2c having a cylindrical outer peripheral surface with a diameter larger than that of the small-diameter portion 2a, and a gear portion 2d on which a gear is formed. The small-diameter portion 2a, spline portion 2b, large-diameter portion 2c, and gear portion 2d are arranged in this order from one axial side (the right side of the paper in FIG. 1 , hereinafter also referred to as the input side) to the other axial side (the left side of the paper in FIG. 1 , hereinafter also referred to as the output side). A gear fixing portion 2e having a cylindrical outer peripheral surface with a diameter smaller than that of the small-diameter portion 2a (the smallest diameter of the output shaft 2) is provided at the input-side end of the output shaft 2.

[0024] The housing 3 integrally comprises a stepped cylindrical portion having a small-diameter cylindrical portion 3a fitted onto the outer periphery of the small-diameter portion 2a of the output shaft 2, a medium-diameter cylindrical portion 3b accommodating the input clutch 10 on its inner periphery, and a large-diameter cylindrical portion 3c accommodating the output clutch 20 on its inner periphery, and a mounting flange 3d (see FIG. 2, etc.) provided at the opening edge of the large-diameter cylindrical portion 3c. The mounting flange 3d has bolt holes through which bolts are inserted when bolting the housing 3 (clutch unit 1) to an attachment target such as an external frame. Furthermore, a disk-shaped portion of the housing 3 connecting the small-diameter cylindrical portion 3a and the medium-diameter cylindrical portion 3b has a plurality of (three in this example; see FIG. 2) pillar portions 3e protruding toward the output side and disposed at equal intervals in the circumferential direction within the annular space of the input clutch 10. The pillar portions 3e divide the annular space into arc-shaped spaces and define the circumferential movement limits of the engaging element of the input clutch 10.

[0025] The input clutch 10 and the operating lever 4 will be described in detail with reference to Figures 1, 2, 4, 6, etc. The input clutch 10 controls the transmission and interruption of torque input by, for example, rotating the operating lever 4 disposed on the side of the seat. The input clutch 10 includes an inner ring 11 as an input rotating member, a lever mounting bracket 12, an outer ring 13 as an output rotating member, and a plurality of engaging elements and elastic members disposed between the inner ring 11 and the outer ring 13. The engaging elements and elastic members in the illustrated example are rollers 14 and coil springs 15, respectively, but other known engaging elements and elastic members may also be used. The inner ring 11 and the outer ring 13 are rotatably fitted onto the outer periphery of the small diameter portion 2a of the output shaft 2.

[0026] The operating lever 4 has a lever body 5 and an operating plate 6. The lever body 5 integrally includes a bottomed cylindrical housing portion 5A that houses the input clutch 10 and the locking mechanism 30, and a grip portion 5B that is gripped by an operator (such as a driver of a vehicle).

[0027] As shown in Figure 6, the operation plate 6 is a disk-shaped member having a non-circular center hole 6a, and is rotatably supported relative to the small-diameter cylindrical portion 3a of the housing 3 via a cylindrical support bushing 7 or the like inserted into the center hole 6a so as to be unable to rotate relative to the small-diameter cylindrical portion 3a. The operation plate 6 further has a lever mounting portion 6b attached to the inner peripheral wall surface of the accommodation portion 5A of the lever main body 5, and a plurality of holes 6c (three in the illustrated example) provided radially outward from the center hole 6a and spaced equally apart in the circumferential direction. The holes 6c are formed as elongated holes extending in the circumferential direction.

[0028] The inner ring 11 is an annular member rotatably fitted onto the outer periphery of the small diameter portion 2a of the output shaft 2. The inner ring 11 has a convex portion 11a that protrudes toward the input side, and by fitting this convex portion 11a into a concave portion 12a provided in the lever mounting bracket 12, the inner ring 11 and the lever mounting bracket 12 can rotate together.

[0029] The lever mounting bracket 12 is provided with a plurality of (three in this example) engaging claws 12b protruding toward the input side at equal intervals in the circumferential direction, and each engaging claw 12b is inserted into a corresponding hole 6c (see FIG. 6 ) in the operation plate 6. When the operation lever 4 in the neutral position is rotated, the engaging claws 12b move along the longitudinal direction (circumferential direction) of the hole 6c and are then inserted into the hole 6c so as to come into contact with the peripheral edge of the hole 6c. Therefore, even if the operation lever 4 in the neutral position is rotated, the lever mounting bracket 12 and the inner ring 11 connected thereto will not rotate together with the operation lever 4 until the operation lever 4 is rotated a predetermined amount (until the rotation restriction on the output shaft 2 by the lock mechanism 30 is released by the operation lever 4 rotating a predetermined amount; details will be described later).

[0030] 2, the outer peripheral surface of the inner ring 11 is composed of a plurality of arc portions 11b having a curvature center at the axis X of the output shaft 2 and a plurality of wedge portions 11c protruding radially outward from the arc portions 11b, and in this embodiment, three arc portions 11b and three wedge portions 11c are provided alternately in the circumferential direction. The inner ring 11 is fitted onto the outer periphery of the small diameter portion 2a of the output shaft 2 in a phase-matched state so that the tops of the wedge portions 11c face the column portions 3e of the housing 3 in the radial direction when no torque is input by lever operation.

[0031] The outer ring 13 is rotatably fitted onto the outer periphery of the small diameter shaft portion 2a of the output shaft 2 on the output side of the inner ring 11. The outer ring 13 integrally comprises a large diameter cylindrical portion 13a that houses the inner ring 11 and the like on its inner periphery, a small diameter cylindrical portion 13b that is disposed adjacent to the output side of the inner ring 11, and a disk-shaped connecting portion 13c that connects the output side end of the large diameter cylindrical portion 13a and the input side end of the small diameter cylindrical portion 13b.

[0032] An annular space is defined between the outer peripheral surface of the inner ring 11 and the opposing inner peripheral surface of the large-diameter cylindrical portion 13a of the outer ring 13, and this annular space is divided into three arc-shaped spaces 16 by three pillar portions 3e provided on the housing 3. Each arc-shaped space 16 contains a pair of rollers 14 (14A, 14B) spaced apart in the circumferential direction, and a coil spring 15 interposed between the pair of rollers 14 in a circumferentially compressed and deformed state. The arc-shaped space 16 has a constant-width portion 16a formed by the arc portion 11b on the outer peripheral surface of the inner ring, and a wedge-shaped portion 16b formed by the wedge portion 11c on the outer peripheral surface of the inner ring, whose radial width gradually decreases toward the circumferential outside of the arc-shaped space 16. When the operating lever 4 is not rotated and no torque is input to the inner ring 11 (FIG. 2), the wedge-shaped portions 16b are provided on both circumferential sides of the constant-width portion 16a.

[0033] When the operating lever 4 is in the neutral position and no torque is being input to the inner ring 11, the pair of rollers 14 are pressed into the wedge-shaped portions 16b of the arc-shaped space 16 by the elastic restoring force of the coil spring 15, and are engaged with both the inner ring 11 and the outer ring 13 (engaged in the circumferential direction with both the inner ring 11 and the outer ring 13), as shown in Figure 2. This restricts the relative rotation between the inner ring 11 and the outer ring 13.

[0034] On the other hand, for example, as shown in Figure 4, when torque T is input to the inner ring 11 to rotate the inner ring 11 counterclockwise by rotating the operating lever 4 in one direction while the operating lever 4 is in the neutral position, the wedge portion 11c of the inner ring 11 contacts the adjacent roller 14 (14B) disposed forward in the rotational direction and applies circumferential pressure to the roller 14B. As a result, the roller 14B moves counterclockwise within the arc-shaped space 16 while compressing and deforming the coil spring 15, while the circumferential movement of the roller 14A is restricted by the column portion 3e of the housing 3. The roller 14B, which is directly subjected to the pressure of the inner ring 11, moves counterclockwise within the arc-shaped space 16 while being pressed into the wedge portion 16b of the arc-shaped space 16, i.e., while being engaged with both the inner ring 11 and the outer ring 13 and restricting their relative rotation. Therefore, when the inner ring 11 rotates counterclockwise, the outer ring 13 also rotates counterclockwise together with the inner ring 11.

[0035] After the inner ring 11 has rotated counterclockwise a predetermined amount, when the inner ring 11 rotates clockwise (torque input to rotate the inner ring 11 clockwise occurs), the roller 14B disengages from the wedge-shaped portion 16b of the arc-shaped space 16, and the engagement between the roller 14B and the inner ring 11 and the outer ring 13 is released, so that only the inner ring 11 of the inner ring 11 and outer ring 13 rotates clockwise (the inner ring 11 rotates freely relative to the outer ring 13). In addition, the roller 14B is subjected to an elastic restoring force accumulated in the coil spring 15 and moves clockwise within the arc-shaped space 16 to follow the rotation of the inner ring 11. When the inner ring 11 rotates clockwise a predetermined amount, the input clutch 10 returns to the initial state shown in FIG. 2 .

[0036] When torque is input to the inner ring 11 to rotate the inner ring 11 clockwise by rotating the operating lever 4 in the other direction while the operating lever 4 is in the neutral position, the wedge portion 11c of the inner ring 11 presses the roller 14A, which is disposed adjacent to the inner ring 11 on the front side in the rotational direction, in the circumferential direction. As a result, the outer ring 13 rotates clockwise together with the inner ring 11 in the same manner as described above. In this case, when torque is input to rotate the inner ring 11 counterclockwise, the input clutch 10 returns to its initial state.

[0037] Next, the output clutch 20 will be described mainly with reference to Figures 1, 3, and 5-6. The output clutch 20 is a reverse input cutoff clutch that transmits torque input from the input clutch 10 to the output shaft 2 while cutting off reverse input torque input to the output shaft 2 without transmitting it to the input clutch 10. The output clutch 20, which is this reverse input cutoff clutch, includes an unlocking member 21 that rotates in response to torque input from the input clutch 10 (the outer ring 13, which is the output rotating member), an inner ring 22 that rotates in response to torque from the input clutch 10 input via the unlocking member 21, an outer ring 23 that constitutes a stationary member whose rotation is restricted, a plurality of engaging elements and elastic members disposed between the inner ring 22 and the outer ring 23, and a friction ring 27. The engaging elements and elastic members in the illustrated example are rollers 24 and coil springs 25, respectively.

[0038] The unlocking member 21 is a disk-shaped member fitted onto the outer periphery of the small-diameter cylindrical portion 13b of the outer ring 13 of the input clutch 10 so as to be rotatable integrally with the outer ring 13, and constitutes the input-side rotating member of the output clutch 20. The unlocking member 21 is provided with a hole 21a penetrating it in the axial direction, and a claw 21b is provided at the outer diameter end thereof, protruding toward the output side and positioned radially outside the inner ring 22 (inside the annular space 26 defined between the inner ring 22 and the outer ring 23). In this embodiment, as shown in Figures 3 and 5, six hole portions 21a and claw portions 21b are provided at equal intervals in the circumferential direction. The hole portions 21a are formed as elongated holes extending in the circumferential direction.

[0039] The inner ring 22 is disposed adjacent to the output side of the unlocking member 21 and is spline-fitted to the spline portion 2b of the output shaft 2. Therefore, the inner ring 22 is rotatable integrally with the output shaft 2 and constitutes the output-side rotating member of the output-side clutch 20. The inner ring 22 is provided with six convex portions 22a that protrude toward the input side and are spaced equally apart in the circumferential direction. Each of the convex portions 22a is inserted into an elongated hole 21a formed in the unlocking member 21. When the operating lever 4 is not rotated and no torque is input from the input-side clutch 10 to the unlocking member 21, the convex portion 22a of the inner ring 22 is located in the circumferential center of the hole 21a (see FIG. 3).

[0040] The outer ring 23 is fixed to the inner peripheral surface of the large-diameter cylindrical portion 3c of the housing 3, and integrally includes a large-diameter cylindrical portion 23a that houses the inner ring 22 on its inner periphery, a small-diameter cylindrical portion 23b that is disposed adjacent to the output side of the inner ring 22, and a disk-shaped connecting portion 23c that connects the output end of the large-diameter cylindrical portion 23a to the input end of the small-diameter cylindrical portion 23b. A friction ring 27 formed in a cylindrical shape from a resin material is fixed to the inner periphery of the small-diameter cylindrical portion 23b, and the inner peripheral surface of this friction ring 27 is pressed against the large-diameter portion 2c of the output shaft 2. This applies rotational resistance to the output shaft 2, preventing excessive rotation of the output shaft 2 when the operating lever 4 is rotated.

[0041] The annular space defined between the inner peripheral surface of the large-diameter cylindrical portion 23a of the outer ring 23 and the outer peripheral surface of the inner ring 22 is divided into six arc-shaped spaces 26 by six claws 21b of the unlocking member 21, which are arranged at equal circumferential intervals within the annular space. Each arc-shaped space 26 contains a pair of rollers 24 (24A, 24B) arranged at a distance from each other in the circumferential direction, and a coil spring 25 interposed between the pair of rollers 24 in a state of being compressed and deformed in the circumferential direction.

[0042] The arc-shaped space 26 is formed in a wedge shape with a radial width that gradually decreases from the circumferential center toward both circumferential ends. This arc-shaped space 26 is formed by forming the inner circumferential surface of the large-diameter cylindrical portion 23a of the outer ring 23, which is the stationary side, into a cylindrical surface with a constant diameter, while forming the outer circumferential surface of the inner ring 22, which is the rotating side, into a non-circular cross section. Here, six wedge-shaped portions 22b that protrude radially outward are continuously arranged in the circumferential direction, thereby forming the outer circumferential surface of the inner ring 22 into a non-circular cross section, and a wedge-shaped arc-shaped space 26 is formed between two circumferentially adjacent wedge-shaped portions 22b. The radial width of the arc-shaped space 26 at the circumferential center is larger than the diameter of the roller 24 by a predetermined amount, and the radial width of the arc-shaped space 26 at both circumferential ends is smaller than the diameter of the roller 24 by a predetermined amount.

[0043] Therefore, when the operating lever 4 is not rotated and no torque is input from the input clutch 10 to the unlocking member 21, both of the pair of rollers 24 arranged in the arc-shaped space 26 are engaged with both the inner ring 22 and the outer ring 23 by the elastic restoring force of the coil spring 25. This maintains a locked state in which relative rotation of the inner ring 22 with respect to the outer ring 23, and further, rotation of the output shaft 2, is restricted. In this locked state, even if reverse input torque is input to the output shaft 2, the reverse input torque is not transmitted to the input clutch 10.

[0044] On the other hand, as shown in Figure 5, for example, when the operating lever 4 is rotated in one direction and torque T that rotates the unlocking member 21 counterclockwise is input to the unlocking member 21 via the input clutch 10, the claws 21b of the unlocking member 21 move counterclockwise within the annular space (arcuate space 26) between the inner ring 22 and the outer ring 23. Accordingly, each claw 21b contacts the adjacent roller 24 (roller 24B in Figure 5) disposed forward in the rotation (movement) direction, and applies pressure to the roller 24B in the circumferential direction. When the roller 24B is pressed in the circumferential direction, the coil spring 25 is compressed and deformed in the circumferential direction, and the roller 24B is released from the position in the arcuate space 26 where it is engaged with both the inner ring 22 and the outer ring 23. This releases the engagement (locked state) between the roller 24B and the inner ring 22 and the outer ring 23. Even if a counterclockwise torque T is input to the unlocking member 21, the roller 24A does not engage with the inner ring 22 and the outer ring 23 and rotates freely.

[0045] Furthermore, when the unlocking member 21 rotates counterclockwise, the convex portion 22a of the inner ring 22 inserted into the hole 21a of the unlocking member 21 abuts against the circumferential edge of the hole 21a, as shown in Figure 5. This allows the unlocking member 21 and the inner ring 22, as well as the output shaft 2 spline-fitted with the inner ring 22, to rotate counterclockwise as one unit. Therefore, when the unlocking member 21 subsequently rotates counterclockwise, the roller 24 and the coil spring 25 between the inner and outer rings 22, 23 move circumferentially counterclockwise, and the inner ring 22 and the rotating shaft 2 rotate counterclockwise. As a result, counterclockwise torque is output from the rotating shaft 2.

[0046] After the unlocking member 21 (and the inner ring 22 and output shaft 2) have rotated counterclockwise by a predetermined amount, if torque is input to rotate the unlocking member 21 clockwise, the roller 24B receives a pressure force due to the release of the elastic restoring force accumulated in the coil spring 25, moves clockwise within the arc-shaped space 26, and engages with both the inner ring 22 and the outer ring 23 in the circumferential direction at the peripheral end of the arc-shaped space 26. This causes the output clutch 20 to return to the locked state shown in FIG. 3 in which it can block reverse input torque.

[0047] Next, the locking mechanism 30 will be described mainly with reference to Figures 1 and 6 to 9. The locking mechanism 30 is disposed on the input side of the input clutch 10, and restricts rotation of the output shaft 2 when the operating lever 4 is not being operated (when the operating lever 4 is in the neutral position). The locking mechanism 30 includes a first gear 31 as a first locking element that is provided so as to be rotatable integrally with the output shaft 2, a second gear 32 as a second locking element whose rotation is restricted, a gear bracket 34, an elastic member 35, and an unlocking member 36.

[0048] The first gear 31 has a generally L-shaped cross section and integrally includes a cylindrical portion 31c fixed to the output shaft 2 (the gear fixing portion 2e of the cylindrical portion 31c) and an annular portion 31a extending radially outward from the output-side end of the cylindrical portion 31c. As shown in FIGS. 6 to 8 , a plurality of external teeth 31b are formed at equal intervals in the circumferential direction on the outer diameter end (outer peripheral surface) of the annular portion 31a. The first gear 31 of this embodiment is fixed to the output shaft 2 so as to be rotatable integrally with the output shaft 2 by press-fitting the cylindrical portion 31c into the outer peripheral surface of the gear fixing portion 2e of the output shaft 2. As shown in an enlarged view in FIG. 9 , the cylindrical portion 31c of the first gear 31 does not contact a stepped surface (the input-side end surface of the small-diameter portion 2a) of the output shaft 2 adjacent thereto in the axial direction, and the output-side end surface of the cylindrical portion 31c faces the stepped surface of the output shaft 2 via an axial gap. Furthermore, the annular portion 31b is not in contact with the support bush 7 adjacent thereto in the axial direction, and the output side end face of the annular portion 31b faces the input side end face of the support bush 7 via an axial gap. This allows for flexibility in selecting the position when fixing the first gear 31 to the output shaft 2, thereby improving the ease of assembly of the locking mechanism 30.

[0049] The first gear 31 is a punched part obtained by punching a metal plate of a predetermined thickness into a predetermined shape using a die set in a press machine, and the external teeth 31b are formed during the punching process. That is, the first gear 31 is obtained by, for example, drawing the center of a metal plate to obtain an intermediate product having a cylindrical portion 31c (and annular portion 31a), and then punching the outer diameter end of the annular portion 31a of this intermediate product into a shape corresponding to the external teeth 31b.

[0050] As shown in Figures 6 to 8, the second gear 32 is a disc-shaped member disposed on the outer diameter side of the first gear 31. The inner diameter end of the second gear 32 has a plurality of protrusions (internal teeth) 32a formed at equal intervals in the circumferential direction, which can mesh with the external teeth 31b of the first gear 31. Like the first gear 31, the second gear 32 is a punched part obtained by punching a metal plate of a predetermined thickness into a predetermined shape using a die set in a press, and the internal teeth 32a are formed during the punching process. The thickness (axial dimension) of the second gear 32 is smaller than the thickness of the annular portion 31a of the first gear 31. Therefore, as shown in Figure 11A, the tooth width (axial dimension) L2 of the internal teeth 32a is smaller than the tooth width L1 of the external teeth 31b.

[0051] The gear bracket 34 is a stepped cylindrical member having a small-diameter cylindrical portion 34a that fits around the outer periphery of the support bush 7, and the second gear 32 is fixed to a flange portion 34b provided at the input end of the gear bracket 34. As shown in FIG. 6 , the small-diameter cylindrical portion 34a has a plurality (three) of notches 34c equally spaced around the circumference, and the outer periphery of the flange portion 34b has a plurality (three) of protruding pieces 34d that protrude radially outward and are also equally spaced around the circumference. Protruding portions 7a that protrude outward from the outer periphery of the support bush 7 fit into the notches 34c of the gear bracket 34 via a small gap. This restricts rotation of the gear bracket 34 (and the second gear 32 fixed thereto) while supporting the gear bracket 34 (and the second gear 32 fixed thereto) on the support bush 7 in an axially movable manner.

[0052] The elastic member 35 is interposed between the annular portion 31a of the first gear 31 and the gear bracket 34 in an axially compressed state, and constantly biases the gear bracket 34 (and the second gear 32 fixed thereto) toward the output side. This elastic member 35 may be a wave washer as shown in FIG. 6, a compression coil spring, or the like.

[0053] The unlocking member 36 is a cylindrical member that houses the gear bracket 34 inside, and is fitted and fixed in the center hole 6a of the operation plate 6 so as to be rotatable integrally with the operation plate 6. The unlocking member 36 has three recesses 36a that can individually house three protrusions 34d provided on the flange portion 34b of the gear bracket 34, and each recess 36a is defined between protrusions 36b provided on both sides in the circumferential direction. The recesses 36a and the protrusions 36b are connected via inclined surfaces that are angled with respect to an axis-parallel plane that is parallel to the axis center X (see the side view shown in FIG. 7).

[0054] 1 and 7, when the operating lever 4 is not rotated and is in the neutral position, the protruding piece 34d of the gear bracket 34 is housed in the recess 36a of the lock release member 36. At this time, in the lock mechanism 30, the external teeth 31b of the first gear 31, which is rotatable integrally with the output shaft 2, are engaged with the internal teeth 32a of the second gear 32, whose rotation is restricted. This restricts the rotation of the output shaft 2.

[0055] Next, when the operating lever 4, which was in the neutral position, is rotated a predetermined amount, the unlocking member 36, which is fixed to the operating plate 6 of the operating lever 4 so as to be rotatable integrally with the operating plate 6, also rotates. Meanwhile, because the rotation of the gear bracket 34 is restricted, when the unlocking member 36 rotates, the protruding piece 34d of the gear bracket 34 housed in the recess 36a of the unlocking member 36 rides up onto the input-side end surface of the protruding portion 36b adjacent to the circumferentially outer side of the recess 36a, as shown in FIG. 8 . Accordingly, the second gear 32 (or the gear bracket 34 to which the second gear 32 is fixed) moves entirely toward the input side while compressing and deforming the elastic member 35 interposed between the gear bracket 34 and the first gear 31 in the axial direction. As a result, the second gear 32 (the internal teeth 32a) is positioned closer to the input side than the first gear 31 (the external teeth 31b), as shown in FIG. 9 . This releases the meshed state between the first gear 31 and the second gear 32, i.e., the rotation restriction of the output shaft 2 by the locking mechanism 30 is released.

[0056] Furthermore, when a rotation operation is performed to return the operating lever 4 to the neutral position, the various parts of the locking mechanism 30 operate in the reverse order to that described above, causing the external teeth 31b of the first gear 31 and the internal teeth 32a of the second gear 32 to mesh again, thereby restricting the rotation of the output shaft 2.

[0057] The individual operating modes of the input clutch 10, the output clutch 20, and the locking mechanism 30 that constitute the clutch unit 1 of this embodiment have been described above. An example of the overall operating mode of the clutch unit 1 will now be briefly described.

[0058] For example, when the operating lever 4, which is in the neutral position, is rotated counterclockwise, torque is first input to the unlocking member 36 that constitutes the locking mechanism 30. As a result, the second gear 32 of the locking mechanism 30 moves axially toward the output side, and the meshing state between the external teeth 31b of the first gear 31, which rotates integrally with the output shaft 2, and the internal teeth 32a of the second gear 32, whose rotation has been restricted, is released (see FIG. 9). As a result, the rotation restriction on the output shaft 2 by the locking mechanism 30 is released, and the output shaft 2 becomes rotatable.

[0059] When the operating lever 4 is further rotated counterclockwise, as shown in FIG. 4 , torque T is input to the inner ring 11 of the input clutch 10, causing the inner ring 11 to rotate counterclockwise. The wedge portion 11c of the inner ring 11 to which torque T is input abuts against the roller 14 (14B) disposed adjacent to the inner ring 11 on the forward side in the rotational direction, applying circumferential pressure to the roller 14B. Accordingly, the roller 14B moves counterclockwise within the arc-shaped space 16 while compressing and deforming the coil spring 15. The roller 14B, which directly receives the pressure from the inner ring 11, moves counterclockwise within the arc-shaped space 16 while being pressed into the wedge portion 16b of the arc-shaped space 16, i.e., while engaging with both the inner ring 11 and the outer ring 13 and restricting their relative rotation. As a result, the outer ring 13, which is the output-side rotating member of the input clutch 10, also rotates counterclockwise together with the inner ring 11.

[0060] As described above, when the outer ring 13, which is the output-side rotating member of the input clutch 10, rotates counterclockwise, torque T is input to the unlocking member 21, which is the input-side rotating member of the output clutch 20, causing it to rotate counterclockwise, as shown in FIG. 5 . Accordingly, the claws 21b of the unlocking member 21, which is disposed in the annular space (arc-shaped space 26) between the inner ring 22 and the outer ring 23, move counterclockwise and come into contact with the adjacent roller 24 (roller 24B in FIG. 5 ) disposed forward in the direction of movement, thereby applying circumferential pressure to the roller 24B. This releases the circumferentially engaged state between the roller 24B and the inner ring 22 and the outer ring 23, i.e., the locked state in which transmission of the reverse input torque input to the output shaft 2 to the input clutch 10 is blocked. Of the pair of rollers 24 (24A, 24B), roller 24A rotates freely without engaging with the inner ring 22 and the outer ring 23, even when counterclockwise torque T is input to the unlocking member 21.

[0061] Furthermore, when counterclockwise torque T is input to the unlocking member 21, the convex portion 22a of the inner ring 22 inserted into the hole 21a of the unlocking member 21 abuts against the peripheral edge of the hole 21a. As a result, the counterclockwise torque T input to the unlocking member 21 is received, and the inner ring 22, which is the output-side rotating member of the output-side clutch 20, and further the output shaft 2 spline-fitted with the inner ring 22, rotate counterclockwise as one unit. As a result, counterclockwise torque is output from the rotating shaft 2.

[0062] As described above, the clutch unit 1 of this embodiment is additionally provided with a locking mechanism 30 that restricts rotation of the output shaft 2 at an axial position different from the output clutch 20 when no torque is input to the input clutch 10 due to lever operation. This strengthens the restriction on rotation of the output shaft 2 when the operating lever 4 is not being operated, effectively reducing the possibility that the locked state of the output clutch 20 will be unintentionally released, causing the output shaft 2 to rotate.

[0063] The locking mechanism 30 of this embodiment restricts the rotation of the output shaft 2 by meshing the external teeth 31 b of the first gear 31, which rotates integrally with the output shaft 2, with the internal teeth 32 a of the second gear 32, whose rotation is restricted, and by moving the second gear 32 toward the input side in response to a lever operation, the meshed state between the external teeth 31 b and the internal teeth 32 a is released. At this time, the tooth width L2 of the internal teeth 32 a of the second gear 32, which moves in the axial direction in response to a lever operation, is set smaller than the tooth width L1 of the external teeth 31 b of the first gear 31, whose axial movement is restricted, so that the relative axial movement amount of both gears 31, 32 (the axial movement amount of the second gear 32) required to release the meshed state between the external teeth 31 b and the internal teeth 32 a can be reduced. This makes it possible to reduce the amount of rotational operation of the operating lever 4 required to release the meshed state of the first gear 31 and second gear 32 that make up the locking mechanism 30, and ultimately to release the locked state of the output side clutch 20, allowing the output shaft 2 to rotate with good responsiveness when the lever is operated.

[0064] In this embodiment, both the first gear 31 having the external teeth 31 b and the second gear having the inner surface 32 a are formed by stamping out metal plate, and both the external teeth 31 b and the internal teeth 32 a are formed in conjunction with stamping out the metal plate. This reduces the manufacturing costs of the gears 31 and 32, and thus reduces the cost increase of the clutch unit 1 in which the lock mechanism 30 is additionally provided.

[0065] When a metal plate is punched from its front surface to its back surface with a die, as shown in FIG. 10 , sagging Ma, shear surfaces Mb, and fracture surfaces (not shown) are sequentially formed on the punched surface of the metal plate M from the front surface (the side where the processing starts) to the back surface (the side where the processing ends). The sagging Ma is a smooth, rounded surface formed when the surface of the metal plate M is pulled by the press die. The shear surfaces Mb are smooth surfaces with visible streaks in the thickness direction. The fracture surfaces are rougher surfaces with a greater surface roughness (poorer surface properties) than the shear surfaces Mb. Considering the cost involved, it is not realistic to perform finishing processes on both gears 31 and 32 to remove the sagging Ma that appears on the outer peripheral surface of the annular portion 31 a of the first gear 31, on which the external teeth 31 b are formed, and the sagging Ma that appears on the inner peripheral surface of the second gear 32, on which the internal teeth 32 a are formed, due to the punching process. Therefore, as shown in Figures 9 and 11A, the outer surface of the annular portion 31a of the first gear 31 on which the external teeth 31b are formed, and the inner surface of the second gear 32 on which the internal teeth 32a are formed are surfaces on which a sag Ma is provided at one end of the metal plate in the thickness direction.

[0066] In this case, as shown in FIG. 11A , when there is no lever operation (the operating lever 4 is in the neutral position), the axial positions of the first gear 31 and the second gear 32 are adjusted so that the punching end ends of the external teeth 31b and the internal teeth 32a, i.e., the end ends opposite the side where the sag Ma is formed, are flush with each other. In this case, the meshing allowance ε between the external teeth 31b and the internal teeth 32a in the tooth width direction can be set equal to the tooth width L2 of the internal teeth 32a. On the other hand, for example, as shown in FIG. 11B , if the first gear 31 and the second gear 32 are arranged so that the end end of the first gear 31 where the sag Ma is formed and the end end of the second gear 32 opposite the side where the sag Ma is formed are flush with each other, the meshing allowance ε between the external teeth 31b and the internal teeth 32a in the tooth width direction becomes smaller than the tooth width L2 of the internal teeth 32a. Therefore, by adopting the configuration shown in FIG. 11A, a large meshing allowance ε between the external teeth 31b and the internal teeth 32a can be ensured, and therefore the rotation restriction on the output shaft 2 can be strengthened appropriately.

[0067] Hereinafter, a second embodiment of the present invention will be described with reference to FIGS.

[0068] 12 is a schematic longitudinal cross-sectional view of a clutch unit 101 according to a second embodiment of the present invention, showing the clutch unit 101 when the operating lever is not operated (when the operating lever is in the neutral position). The clutch unit 101 is used, for example, in a seat lifter for adjusting the height of a vehicle seat. The clutch unit 101 includes an output shaft 102 rotatably mounted about an axis X, a housing 103, an operating lever 104, an input clutch 110, an output clutch 120, and a mechanical locking mechanism 130. In the following description, the terms "axial direction," "radial direction," and "circumferential direction" used to indicate directionality refer to a direction parallel to the axis X of the output shaft 102, a radial direction of a circle centered on the axis X, and a circumferential direction of a circle centered on the axis X, respectively. Furthermore, unless otherwise specified, "rotation" in the following description refers to rotation about the axis X of the output shaft 102.

[0069] The output shaft 102 includes a small-diameter portion 102a having a cylindrical outer circumferential surface with a constant diameter, a spline portion 102b having a spline (male spline) formed therein, a large-diameter portion 102c having a cylindrical outer circumferential surface with a larger diameter than the small-diameter portion 102a, and a gear portion 102d having a gear formed therein. The small-diameter portion 102a, spline portion 102b, large-diameter portion 102c, and gear portion 102d are arranged in this order from one axial side (the right side of the paper in FIG. 12 , hereinafter also referred to as the input side) to the other axial side (the left side of the paper in FIG. 12 , hereinafter also referred to as the output side).

[0070] The housing 103 integrally comprises a stepped cylindrical portion having a small-diameter cylindrical portion 103a fitted onto the outer periphery of the small-diameter portion 102a of the output shaft 102, a medium-diameter cylindrical portion 103b accommodating the input clutch 110 on its inner periphery, and a large-diameter cylindrical portion 103c accommodating the output clutch 120 on its inner periphery, and an attachment flange 103d (see FIG. 13 , etc.) provided at the opening edge of the large-diameter cylindrical portion 103c. The attachment flange 103d has bolt holes through which bolts are inserted when bolting the housing 103 (clutch unit 101) to an attachment target such as an external frame. Furthermore, a disk-shaped portion of the housing 103 connecting the small-diameter cylindrical portion 103a and the medium-diameter cylindrical portion 103b has a plurality of (three in this example; see FIG. 13 ) pillars 103e equally spaced circumferentially, protruding toward the output side and positioned within the annular space of the input clutch 110. The pillar portion 103e divides the annular space into arc-shaped spaces and defines the circumferential movement limit of the engaging element of the input clutch 110.

[0071] The input clutch 110 and the operating lever 104 will be described in detail with reference to Figures 12, 13, 15, 17, etc. The input clutch 110 controls the transmission and interruption of torque input by rotating the operating lever 104, which is disposed, for example, on the side of the seat. The input clutch 110 includes an inner ring 111 as an input rotating member, a lever mounting bracket 112, an outer ring 113 as an output rotating member, and a plurality of engaging elements and elastic members disposed between the inner ring 111 and the outer ring 113. The engaging elements and elastic members in the illustrated example are rollers 114 and coil springs 115, respectively. The inner ring 111 and the outer ring 113 are rotatably fitted onto the outer periphery of the small diameter portion 102a of the output shaft 102.

[0072] The operating lever 104 has a lever body 105 and an operating plate 106. The lever body 105 integrally includes a bottomed cylindrical housing portion 105A that houses the input clutch 110 and the locking mechanism 130, and a grip portion 105B that is gripped by an operator (such as a driver of a vehicle).

[0073] 17, the operation plate 106 is a disk-shaped member having a non-circular center hole 106a, and is rotatably supported relative to the small-diameter cylindrical portion 103a of the housing 103 via a cylindrical support bush 107 or the like inserted into the center hole 106a so as to be unable to rotate relative to the operation plate 106. The operation plate 106 further has a lever attachment portion 106b attached to the inner peripheral wall surface of the accommodation portion 105A of the lever main body 105, and a plurality of holes 106c (three in the illustrated example) provided radially outward from the center hole 106a and spaced at equal intervals in the circumferential direction. The holes 106c are formed as elongated holes extending in the circumferential direction.

[0074] The inner ring 111 is an annular member rotatably fitted onto the outer periphery of the small diameter portion 102a of the output shaft 102. The inner ring 111 has a convex portion 111a that protrudes toward the input side, and by fitting this convex portion 111a into a concave portion 112a provided in the lever mounting bracket 112, the inner ring 111 and the lever mounting bracket 112 can rotate together.

[0075] The lever mounting bracket 112 is provided with a plurality of (three in this example) engaging claws 112b protruding toward the input side at equal intervals in the circumferential direction, and each engaging claw 112b is inserted into a corresponding hole 106c (see FIG. 17 ) of the operation plate 106. When the operation lever 104 in the neutral position is rotated, the engaging claws 112b move along the longitudinal direction (circumferential direction) of the hole 106c and are then inserted into the hole 106c so as to come into contact with the peripheral end of the hole 106c. Therefore, even if the operation lever 104 in the neutral position is rotated, the lever mounting bracket 112 and the inner ring 111 connected thereto do not rotate together with the operation lever 104 until the operation lever 104 rotates a predetermined amount (until the lock mechanism 130 releases the restriction on rotation of the output shaft 102 by rotating the operation lever 104 a predetermined amount; the lock mechanism 130 will be described in detail later).

[0076] 13, the outer peripheral surface of the inner ring 111 is composed of a plurality of arc portions 111b having a curvature center at the axis X of the output shaft 102 and a plurality of wedge portions 111c protruding radially outward from the arc portions 111b, and in this embodiment, three arc portions 111b and three wedge portions 111c are provided alternately in the circumferential direction. The inner ring 111 is fitted onto the outer periphery of the small diameter portion 102a of the output shaft 102 in a phase-matched state so that the tops of the wedge portions 111c face the pillar portions 103e of the housing 103 in the radial direction when no torque is input by lever operation.

[0077] The outer ring 113 is rotatably fitted onto the outer periphery of the small diameter shaft portion 102a of the output shaft 102 on the output side of the inner ring 111. The outer ring 113 integrally includes a large diameter cylindrical portion 113a that houses the inner ring 111 and the like on its inner periphery, a small diameter cylindrical portion 113b that is disposed adjacent to the output side of the inner ring 111, and a disk-shaped connecting portion 113c that connects the output side end of the large diameter cylindrical portion 113a and the input side end of the small diameter cylindrical portion 113b.

[0078] An annular space is defined between the outer peripheral surface of the inner ring 111 and the inner peripheral surface of the large-diameter cylindrical portion 113a of the opposing outer ring 113, and this annular space is divided into three arc-shaped spaces 116 by three pillar portions 103e provided on the housing 103. Each arc-shaped space 116 contains a pair of rollers 114 (114A, 114B) spaced apart in the circumferential direction, and a coil spring 115 interposed between the pair of rollers 114 in a state of being compressed and deformed in the circumferential direction. The arc-shaped space 116 has an equal-width portion 116a with a constant radial width formed by the arc portion 111b on the outer peripheral surface of the inner ring, and wedge-shaped portions 116b formed by the wedge portions 111c on the outer peripheral surface of the inner ring, whose radial width gradually decreases toward the outside in the circumferential direction of the arc-shaped space 116; when no torque is input to the inner ring 111 by lever operation (Figure 2), the wedge-shaped portions 116b are provided on both circumferential sides of the equal-width portion 116a.

[0079] 13 , when no torque is input to the inner ring 111, the pair of rollers 114 are pressed into the wedge-shaped portions 116b of the arc-shaped space 116 by the elastic restoring force of the coil spring 115 and are engaged with both the inner ring 111 and the outer ring 113 (engaged with both the inner ring 111 and the outer ring 113 in the circumferential direction). This restricts relative rotation between the inner ring 111 and the outer ring 113.

[0080] 15, for example, when torque T is input to the inner ring 111 to rotate the operating lever 104 in one direction, causing the inner ring 111 to rotate counterclockwise, the wedge portion 111c of the inner ring 111 comes into contact with the roller 114 (114B) disposed adjacent to the inner ring 111 on the front side in the rotational direction, and applies pressure to the roller 114B in the circumferential direction. Accordingly, the roller 114B moves counterclockwise within the arc-shaped space 116 while compressing and deforming the coil spring 115, while the circumferential movement of the roller 114A is restricted by the pillar portion 103e of the housing 103. The roller 114B, which is directly subjected to the pressure of the inner ring 111, moves counterclockwise within the arc-shaped space 116 while being pushed into the wedge-shaped portion 116b of the arc-shaped space 116, i.e., while being engaged with both the inner ring 111 and the outer ring 113 and restricting the relative rotation between them, so that the outer ring 113 also rotates counterclockwise together with the inner ring 111.

[0081] After the inner ring 111 has rotated counterclockwise a predetermined amount, when the inner ring 111 rotates clockwise (torque input to rotate the inner ring 111 clockwise occurs), the roller 114B disengages from the wedge-shaped portion 116b of the arc-shaped space 116, and the engagement between the roller 114B and the inner ring 111 and the outer ring 113 is released, so that only the inner ring 111 rotates clockwise (the inner ring 111 rotates freely relative to the outer ring 113). Furthermore, the roller 114B is subjected to an elastic restoring force accumulated in the coil spring 115, and moves clockwise within the arc-shaped space 116 to follow the rotation of the inner ring 111. When the inner ring 111 rotates clockwise a predetermined amount, the input clutch 110 returns to the initial state shown in FIG. 13 .

[0082] When torque is input to the inner ring 111 to rotate the inner ring 111 clockwise by rotating the operating lever 104 in the other direction, the wedge portion 111c of the inner ring 111 presses the roller 114A, which is disposed adjacent to the inner ring 111 on the front side in the rotational direction, in the circumferential direction. As a result, the outer ring 113 rotates clockwise together with the inner ring 111 in the same manner as described above. In this case, when torque is input to rotate the inner ring 111 counterclockwise, the input clutch 110 returns to its initial state.

[0083] Next, the output clutch 120 will be described mainly with reference to Figures 12, 14, and 16-17. The output clutch 120 is a reverse input cutoff clutch that transmits torque input from the input clutch 110 to the output shaft 102 while cutting off reverse input torque input to the output shaft 102 without transmitting it to the input clutch 110. The output clutch 120, which is this reverse input cutoff clutch, includes an unlocking member 121 that rotates in response to torque input from the input clutch 110 (the outer ring 113, which is the output rotating member), an inner ring 122 that rotates in response to torque from the input clutch 110 input via the unlocking member 121, an outer ring 123 that constitutes a stationary member whose rotation is restricted, a plurality of engaging elements and elastic members disposed between the inner ring 122 and the outer ring 123, and a friction ring 127. The engaging elements and elastic members in the illustrated example are rollers 124 and coil springs 125, respectively.

[0084] The unlocking member 121 is a disk-shaped member fitted onto the outer periphery of the small-diameter cylindrical portion 113b of the outer ring 113 of the input clutch 110 so as to be rotatable integrally with the outer ring 113, and constitutes the input-side rotating member of the output clutch 120. The unlocking member 121 is provided with a hole 121a penetrating the member in the axial direction, and a claw 121b is provided at the outer diameter end thereof, protruding toward the output side and positioned radially outside the inner ring 122 (inside the annular space 126 defined between the inner ring 122 and the outer ring 123). In this embodiment, as shown in FIGS. 14 and 16 , six holes 121a and six claws 121b are provided at equal intervals in the circumferential direction. The hole 121a is formed as an elongated hole extending in the circumferential direction.

[0085] The inner ring 122 is disposed adjacent to the output side of the unlocking member 121 and is spline-fitted to the spline portion 102b of the output shaft 102. Therefore, the inner ring 122 is rotatable integrally with the output shaft 102 and constitutes the output-side rotating member of the output-side clutch 120. The inner ring 122 is provided with six convex portions 122a that protrude toward the input side and are spaced equally apart in the circumferential direction. Each of the convex portions 122a is inserted into an elongated hole 121a formed in the unlocking member 121. When the operating lever 104 is not rotated and no torque is input from the input-side clutch 110 to the unlocking member 121, the convex portion 122a of the inner ring 122 is located in the circumferential center of the hole 121a (see FIG. 3).

[0086] The outer ring 123 is fixed to the inner peripheral surface of the large-diameter cylindrical portion 103c of the housing 103, and integrally includes a large-diameter cylindrical portion 123a that houses the inner ring 122 within its inner periphery, a small-diameter cylindrical portion 123b that is disposed adjacent to the output side of the inner ring 122, and a disk-shaped connecting portion 123c that connects the output end of the large-diameter cylindrical portion 123a to the input end of the small-diameter cylindrical portion 123b. A friction ring 127 formed in a cylindrical shape from a resin material is fixed to the inner periphery of the small-diameter cylindrical portion 123b, and the inner peripheral surface of this friction ring 127 is in pressure contact with the large-diameter portion 102c of the output shaft 102. This provides rotational resistance to the output shaft 102, thereby preventing excessive rotation of the output shaft 102 when the operating lever 104 is rotated.

[0087] The annular space defined between the inner peripheral surface of the large-diameter cylindrical portion 123a of the outer ring 123 and the outer peripheral surface of the inner ring 122 is divided into six arc-shaped spaces 126 by six claws 121b of the unlocking member 121, which are arranged at equal circumferential intervals within the annular space. Each arc-shaped space 126 contains a pair of rollers 124 (124A, 124B) arranged at a distance from each other in the circumferential direction, and a coil spring 125 interposed between the pair of rollers 124 in a circumferentially compressed and deformed state.

[0088] The arc-shaped space 126 is formed in a wedge shape with a radial width that gradually decreases from the circumferential center toward both circumferential ends. This arc-shaped space 126 as a wedge gap is formed by forming the inner circumferential surface of the large-diameter cylindrical portion 123a of the outer ring 123, which is the stationary side, into a cylindrical surface with a constant diameter, while forming the outer circumferential surface of the inner ring 122, which is the rotating side, into a non-circular cross section. Here, six wedge-shaped portions 122b protruding radially outward are continuously arranged in the circumferential direction, thereby forming the outer circumferential surface of the inner ring 122 into a non-circular cross section, and a wedge-shaped arc-shaped space 126 is formed between two circumferentially adjacent wedge-shaped portions 122b. The radial width of the arc-shaped space 126 at the circumferential center is larger than the diameter of the roller 124 by a predetermined amount, and the radial width of the arc-shaped space 126 at both circumferential ends is smaller than the diameter of the roller 124 by a predetermined amount.

[0089] Therefore, when the operating lever 104 is not rotated and no torque is input from the input clutch 110 to the unlocking member 121, both of the pair of rollers 124 arranged in the arc-shaped space 126 are engaged with both the inner ring 122 and the outer ring 123 by the elastic restoring force of the coil spring 125. This maintains a locked state in which bidirectional relative rotation of the inner ring 122 with respect to the outer ring 123, and further, rotation of the output shaft 102, is restricted. In this locked state, even if reverse input torque is input to the output shaft 102, the reverse input torque is not transmitted to the input clutch 110.

[0090] On the other hand, as shown in Figure 16, for example, when the operating lever 104 is rotated in one direction, torque T that rotates the unlocking member 121 counterclockwise is input to the unlocking member 121 via the input clutch 110, causing the claws 121b of the unlocking member 121 to move counterclockwise within the annular space (arc-shaped space 126) between the inner ring 122 and the outer ring 123. As a result, each claw 121b contacts the adjacent roller 124 (roller 124B in Figure 16) disposed forward in the direction of movement, applying pressure to the roller 124B in the circumferential direction. When the roller 124B is pressed in the circumferential direction, the coil spring 125 is compressed and deformed in the circumferential direction, causing the roller 124B to move away from the position in the arc-shaped space 126 where it is engaged with both the inner ring 122 and the outer ring 123, thereby releasing the circumferential engagement (locked state) between the roller 124B and the inner ring 122 and the outer ring 123. Even if a counterclockwise torque T is input to the unlocking member 121, the roller 124A does not engage with the inner ring 122 and the outer ring 123 and rotates freely.

[0091] Furthermore, when the unlocking member 121 rotates counterclockwise, the convex portion 122a of the inner ring 122 inserted into the hole 121a of the unlocking member 121 abuts against the peripheral edge of the hole 121a, as shown in Figure 16. This allows the unlocking member 121 and the inner ring 122, as well as the output shaft 102 spline-fitted with the inner ring 122, to rotate counterclockwise as one unit. Therefore, when the unlocking member 121 subsequently rotates counterclockwise, the roller 124 and the coil spring 125 between the inner and outer rings 122 and 123 move counterclockwise in the circumferential direction, and the inner ring 122 and the rotating shaft 102 rotate counterclockwise. As a result, counterclockwise torque is output from the rotating shaft 102.

[0092] When torque is input to rotate the unlocking member 121 clockwise, the roller 124B receives a pressure force due to the release of the elastic restoring force accumulated in the coil spring 125, moves clockwise within the arc-shaped space 126, and engages with both the inner ring 122 and the outer ring 123 in the circumferential direction at the peripheral end of the arc-shaped space 126. This causes the output clutch 120 to return to a locked state in which reverse input torque is blocked.

[0093] Next, the locking mechanism 130 will be described mainly with reference to Figures 12 and 17 to 20. The locking mechanism 130 is disposed on the input side of the input clutch 110, and restricts rotation of the output shaft 102 when the operating lever 104 is not being operated. The locking mechanism 130 includes a first locking element 131 that is provided so as to be rotatable integrally with the output shaft 102, a second locking element 132 that is disposed radially outward of the first locking element 131 and whose rotation is restricted, an elastic member 135, and an unlocking member 136.

[0094] The first locking element 131 has an annular male gear portion 131a with a plurality of external teeth 131b formed at equal circumferential intervals on its outer diameter end (outer peripheral surface), and is fixed by an appropriate means such as press fitting to the outer peripheral surface of the small diameter portion 102a of the output shaft 102. The first locking element 131 of this type is obtained, for example, by performing a press-punching process on a metal plate of a predetermined thickness to obtain a disk-shaped intermediate product with a plurality of external teeth 131b formed thereon, and then performing a drawing process on the center of this intermediate product to form a cylindrical portion to be fixed to the output shaft 102.

[0095] The second locking element 132 has an annular female gear portion 133 on its inner diameter end (inner peripheral surface) where internal teeth 133a that can mesh with the external teeth 131b of the first locking element 131 are formed at equal intervals in the circumferential direction, and a gear support portion 134 that is formed as a separate member from the female gear portion 133 and fixedly supports the female gear portion 133. As with the first locking element 131, the female gear portion 133 is obtained by press-punching a metal plate of a predetermined thickness.

[0096] The tooth width of the external teeth 131b of the first locking element 131 (which can also be said to be the axial width of the male gear portion 131a, or the thickness of the metal plate that is the base material of the first locking element 131) is within a range of 1.2 mm to 3.0 mm, and the tooth width of the internal teeth 133a (which can also be said to be the axial width of the female gear portion 133, or the thickness of the metal plate that is the base material of the male gear portion 133) is within a range of 0.6 mm to 1.6 mm, which is smaller than the tooth width of the external teeth 131b. As a specific example, the tooth width of the external teeth 131b can be 2.0 mm, and in this case, the tooth width of the internal teeth 133a is set to 0.8 mm, taking into account the balance between the weight and strength of the female gear portion 133. The tooth width of the external teeth 131b is made larger than the tooth width of the internal teeth 133a for the following reasons: (1) to enable the first locking element 131, which is integrally formed with the external teeth 131b, to be firmly fixed to the outer circumferential surface of the output shaft 102, which is the rotating shaft, and (2) to enable the external teeth 131b and the internal teeth 133a to mesh appropriately. In other words, with regard to (2) above, if the tooth widths of both are the same, a sufficient meshing length cannot be ensured unless the axial positions of both teeth are aligned.

[0097] The gear support portion 134 is a stepped cylindrical member having a small-diameter cylindrical portion 134a that fits onto the outer periphery of the support bush 107, and a flange portion 134b provided at the input end fixedly supports the male gear portion 133. As shown in FIG. 17 , the small-diameter cylindrical portion 134a has a plurality (three) of notches 134c equally spaced circumferentially, and the outer periphery of the flange portion 134b has a plurality (three) of protruding pieces 134d that protrude radially outward, also equally spaced circumferentially. Protruding portions 107a that protrude outward from the outer periphery of the support bush 107 fit into the notches 134c of the gear support portion 134 via a small gap. As a result, the gear support portion 134 (including the second locking element 132) is restricted from rotating relative to the support bush 107 and is supported by the support bush 107 in a manner that allows linear movement in the axial direction.

[0098] The elastic member 135 is interposed in an axially compressed state between the male gear portion 131b of the first locking element 131 and the gear support portion 134 of the second locking element 132, and constantly biases the second locking element 132 toward the output side. This elastic member 135 may be a wave washer as shown in FIG. 17, a compression coil spring, or the like.

[0099] The unlocking member 136 is a cylindrical member that houses the second locking element 132 (the gear support portion 134 thereof) on its inner periphery, and is fitted and fixed in the central hole 106a of the operation plate 106 so as to be rotatable integrally with the operation plate 106. The unlocking member 136 has recesses 136a that can individually house three protruding pieces 134d provided on the flange portion 134b of the gear support portion 134, and each recess 136a is defined between protruding portions 136b provided on both sides in the circumferential direction. The recesses 136a and the protruding portions 136b are connected via inclined surfaces that form an angle with respect to an axis-parallel plane that is parallel to the axis center X (see the side view shown in Figure 18).

[0100] 12 and 18, when the operating lever 104 is in the neutral position, the protruding piece 134d of the gear support portion 134 that constitutes the second locking element 132 is housed in the recess 136a of the lock release member 136. At this time, in the locking mechanism portion 130, the male gear portion 131a (external teeth 131b) of the first locking element 131 that can rotate integrally with the output shaft 102 is engaged with the female gear portion 133 (internal teeth 133a) of the second locking element 132 whose rotation is restricted. This restricts the rotation of the output shaft 102.

[0101] Next, when the operating lever 104, which was in the neutral position, is rotated in one circumferential direction, the unlocking member 136, which is fixed to the operating plate 106 of the operating lever 104 so as to be rotatable integrally with the operating plate 106, also rotates. Meanwhile, because the rotation of the gear support portion 134 of the second locking element 132 is restricted, when the unlocking member 136 rotates, the protruding piece 134d of the gear support portion 134 housed in the recess 136a of the unlocking member 136 rides up onto the input-side end surface of the protrusion 136b adjacent to the circumferentially outer side of the recess 136a, as shown in Figure 19. Accordingly, the second locking element 132 moves overall toward the input side while compressing and deforming the elastic member 135 interposed between the first locking element 131 and the second locking element 132 in the axial direction, and the female gear portion 133 (the internal teeth 133a) is positioned closer to the input side than the male gear portion 131a (the external teeth 131b), as shown in Figure 20. As a result, the meshing state between the male gear portion 131a and the female gear portion 133, that is, the restriction on rotation of the output shaft 102 by the lock mechanism 130, is released.

[0102] In addition, in the lock mechanism 130 configured as described above, even if a rotation operation (rotation operation toward the other circumferential direction) is performed to return the operating lever 104 to the neutral position, the external teeth 131b of the male gear portion 131a constituting the first locking element 131 and the internal teeth 133a of the female gear portion 133 of the second locking element 132 do not necessarily re-engage with each other, and there is a possibility that they will not mesh due to a phase misalignment between the external teeth 131b and the internal teeth 133a. Even if the external teeth 131b and the internal teeth 133a do not mesh due to the phase misalignment, the first locking element 131 fixed to the output shaft 102 will rotate together with the output shaft 102 as the output shaft 102 rotates (slightly) due to slight slippage occurring in the output-side clutch 120 due to vehicle vibrations, etc. Then, with this rotation, the external teeth 131b and the internal teeth 133a mesh with each other, and the rotation of the output shaft 102 is restricted by the lock mechanism 130.

[0103] The individual operating modes of the input clutch 110, the output clutch 120, and the locking mechanism 130 that constitute the clutch unit 101 of this embodiment have been described above. An example of the overall operating mode of the clutch unit 101 will now be briefly described.

[0104] For example, when the operating lever 104, which is in the neutral position, is rotated counterclockwise, torque is first input to the unlocking member 136 that constitutes the locking mechanism 130. Accordingly, the second locking element 132 of the locking mechanism 130 moves axially toward the output side, and the meshing state between the male gear portion 131a of the first locking element 131, which rotates integrally with the output shaft 102, and the female gear portion 133 of the second locking element 132, whose rotation has been restricted, is released (see FIG. 20 ). This releases the rotation restriction on the output shaft 102 imposed by the locking mechanism 130, and the output shaft 102 becomes rotatable.

[0105] When the operating lever 104 is further rotated counterclockwise, as shown in Figure 15, torque T is input to the inner ring 111 of the input clutch 110, causing the inner ring 111 to rotate counterclockwise. The wedge portion 111c of the inner ring 111 to which torque T is input abuts against the roller 114 (114B) disposed adjacent to the inner ring 111 on the front side in the rotational direction, and applies pressure to the roller 114B in the circumferential direction. Accordingly, the roller 114B moves counterclockwise within the arc-shaped space 116 while compressing and deforming the coil spring 115. The roller 114B, which is directly subjected to the pressure of the inner ring 111, moves counterclockwise within the arc-shaped space 116 while being pushed into the wedge-shaped portion 116b of the arc-shaped space 116, i.e., while being engaged with both the inner ring 111 and the outer ring 1113 and restricting the relative rotation between them, so that the outer ring 113, which is the output side rotating member of the input side clutch 110, also rotates counterclockwise together with the inner ring 111.

[0106] As described above, when the outer ring 113, which is the output-side rotating member of the input clutch 110, rotates counterclockwise, a torque T is input to the unlocking member 121, which is the input-side rotating member of the output clutch 120, causing it to rotate counterclockwise, as shown in Fig. 16. Accordingly, the claws 121b of the unlocking member 121, which are disposed in the arc-shaped space 126 between the inner ring 122 and the outer ring 123, move counterclockwise and come into contact with the roller 124 (roller 124B in Fig. 16) disposed adjacent to and ahead of the movement direction, thereby applying pressure to the roller 124B in the circumferential direction. This releases the circumferentially engaged state between the roller 124B and the inner ring 122 and the outer ring 123, i.e., the locked state in which transmission of the reverse input torque input to the output shaft 102 to the input clutch 110 is interrupted. Of the pair of rollers 124 (124A, 124B), the roller 124A does not engage with the inner ring 122 and the outer ring 123 and rotates freely even when a counterclockwise torque T is input to the unlocking member 121.

[0107] Furthermore, when counterclockwise torque T is input to the unlocking member 121, the convex portion 122a of the inner ring 122 inserted into the hole 121a of the unlocking member 121 abuts against the peripheral edge of the hole 121a. As a result, the counterclockwise torque T input to the unlocking member 121 is received, and the inner ring 122, which is the output-side rotating member of the output-side clutch 120, and further the output shaft 102, which is spline-fitted with the inner ring 122, rotate counterclockwise as one unit. As a result, counterclockwise torque is output from the rotating shaft 102.

[0108] As described above, in the clutch unit 101 of this embodiment, when there is no lever operation (when the operating lever 104 is not rotated), the locking mechanism 130 is additionally provided to restrict rotation of the output shaft 102 at an axial position different from the output side clutch 120 (toward the input side of the input side clutch 110), and therefore, rotation restriction on the output shaft 102 can be strengthened, thereby reducing the possibility of the output shaft 102 rotating unintentionally.

[0109] The locking mechanism 130 of this embodiment restricts the rotation of the output shaft 102 by meshing the external teeth 131b of the first locking element 131, which rotates integrally with the output shaft 102, with the internal teeth 133a of the second locking element 132, whose rotation is restricted, and by operating the lever, the second locking element 132 moves toward the input side, thereby releasing the meshed state between the external teeth 131b and the internal teeth 133a. In this case, as shown in the enlarged view of Figure 18, various problems may occur if the gap width w1 (in other words, the meshing allowance between the teeth) of the radial gap α1 formed between the external teeth 131b (tooth tip 137) and the internal teeth 133a (tooth bottom 138) is not controlled within an appropriate range.

[0110] Specifically, if the gap width w1 of the radial gap α1 is large and the meshing allowance between the teeth 131b and 133a is small (specifically, if w1 > 0.4 mm), the allowable torque will be small, which may make it impossible to properly restrict the rotation of the output shaft 102. In addition, the meshing surface pressure will increase, which may result in damage to either or both of the male gear portion 131a of the first locking element 131 and the female gear portion 133 of the second locking element 132. Conversely, if the gap width w1 of the radial gap α1 is small and the meshing allowance between the teeth 131b and 133a is large (specifically, if w1 < 0.2 mm), it will be difficult to tolerate even slight misalignment between the male gear portion 131a and the female gear portion 133 due to dimensional tolerances of the respective components, making it difficult to achieve appropriate meshing and disengagement states between the teeth 131b and 133a (locked and unlocked states of the locking mechanism 130). Therefore, the width w1 of the radial gap α1 is controlled within a range of 0.2 mm to 0.4 mm, thereby making it possible to appropriately realize and maintain the rotation restriction state of the output shaft 102.

[0111] When the clutch unit 101 of this embodiment is incorporated into a seat lifter for an automobile, the tooth height (total tooth height) of the teeth 131b, 133a is selected to be within a range of 7 mm to 15 mm for the male gear portion 131 and the female gear portion 133. If the tooth height is too small, the allowable torque will be insufficient, and if the tooth height is too large, the weight will increase and the allowable torque will be excessive.

[0112] 18, the width of the circumferential gap β1 formed between the circumferential end faces of the external tooth 131b and the internal tooth 133a is preferably equal to or less than the width of the radial gap α1. If the width of the circumferential gap β1 is too large, the circumferential backlash during locking may become large, potentially causing discomfort or anxiety to the vehicle occupants (operators). Strictly speaking, the width of the circumferential gap β1 referred to here is the width of the circumferential gap β1 formed between the circumferential end faces of the external tooth 131b and the internal tooth 133a when the external tooth 131b is in a neutral position (a position where the circumferential center of the external tooth 131b coincides with the circumferential center of the recess formed between two adjacent internal teeth 133a). Furthermore, assuming that the gap width of the circumferential gap β1 formed at one circumferential end surface of the external tooth 131b is z11 and the gap width of the circumferential gap β1 formed at the other circumferential end surface of the external tooth 131b is z12, the value is calculated using the formula gap width = (z11 + z12) / 2.

[0113] In this embodiment, the first locking element 131 having the external teeth 131b and the female gear portion 133 of the second locking element 132 having the internal teeth 133a are formed as parts stamped out of a metal plate, thereby suppressing the manufacturing costs of both locking elements 131, 132, and thus the increase in the cost of the clutch unit 101 in which the locking mechanism 130 is additionally provided.

[0114] When a metal plate is subjected to a press punching process from the front surface to the back surface, as shown schematically in FIG. 21A , sagging Ma1, shear surfaces Mb1, and fracture surfaces Mc1 are formed in this order on the punched surface of the metal plate M1, and burrs Md1 are also typically formed. The sagging Ma1 is a smooth, rounded surface formed when the surface of the metal plate M1 is pulled by a press die. The shear surfaces Mb1 are smooth surfaces with visible lines in the thickness direction (press direction). The fracture surfaces Mc1 are rough surfaces (uneven surfaces) that appear as if a portion of the material has been torn off. The burrs Md1 are protrusions that protrude outward in the thickness direction of the metal plate M1 beyond the back surface of the metal plate M1. The sagging Ma1, shear surfaces Mb1, fracture surfaces Mc1, and burrs Md1 that may appear (or may potentially appear) on the punched surface of the metal plate M1 can be removed by additional finishing processes such as grinding and polishing, but this inevitably increases costs due to the additional processing steps.

[0115] Therefore, it is preferable that the female gear portions 133 constituting the first locking element 131 and the second locking element 132 be press-punched parts having the above-mentioned sheared surface Mb1, i.e., press-punched parts having a punched surface in which finishing processes, etc., are omitted and the surface condition obtained by punching is maintained. However, in this case, as shown in FIG. 21B , press-punched parts in which the length d1 of the sheared surface Mb1 in the thickness direction of the metal plate M1 is 70% or more of the thickness d of the metal plate M1 are used for the male gear portions 133 of the first locking element 131 and the second locking element 132. This improves the meshing accuracy between the external teeth 131b of the first locking element 131 and the internal teeth 133a of the second locking element 132 (reducing the possibility of poor meshing between the external teeth 131b and the internal teeth 133a), allowing the locking mechanism 130 to appropriately restrict rotation of the output shaft 102.

[0116] Furthermore, when portions with continuous minute irregularities, such as the external teeth 131b of the first locking element 131 and the internal teeth 133a of the second locking element 132 (the female gear portion 133 constituting the second locking element 132), are formed by punching, the amount of sagging d2 in the thickness direction of the metal plate M1 (the length of the sagging Ma1) tends to increase. As the amount of sagging increases, the length d1 of the shear surface Mb1 becomes relatively shorter, making it more difficult to mesh the teeth with precision. For this reason, it is preferable that the amount of sagging d2 of the external teeth 131b of the first locking element 131 and the internal teeth 133a of the male gear portion 133 be 40% or less of the thickness d of the metal plate M1 at the tooth tips (portions that mesh with the mating teeth) and 20% or less in the region excluding the tooth tips. This increases the meshing accuracy between the outer peripheral tooth surface 131 b of the first locking element 131 and the inner peripheral tooth surface 133 a of the second locking element 132 , thereby effectively restricting the rotation of the output shaft 102 by the locking mechanism 130 .

[0117] The clutch units 1, 101 according to the first and second embodiments of the present invention have been described above, but appropriate modifications can be made to the clutch units 1, 101 without departing from the spirit of the present invention. For example, the output clutch 20, 120 can be configured with a clutch other than the roller clutch described above.

[0118] The present invention can be embodied in various forms without departing from the spirit of the invention. The scope of the present invention is defined by the claims, and includes the equivalent meanings of the claims and all modifications within the scope of the claims.

[0119] DESCRIPTION OF SYMBOLS 1 Clutch unit 2 Output shaft 3 Housing 4 Operating lever 5 Lever body 6 Operating plate 7 Support bush 10 Input side clutch 20 Output side clutch 30 Locking mechanism 31 First gear (first locking element) 31b External teeth 32 Second gear (second locking element) 32a Internal teeth L1 (External teeth) Tooth width L2 (Internal teeth) Tooth width M Metal plate Ma Sagging 101 Clutch unit 102 Output shaft 103 Housing 104 Operating lever 105 Lever body 106 Operating plate 107 Support bush 110 Input side clutch 120 Output side clutch 130 Locking mechanism 131 First locking element 131b External teeth 132 Second locking element 133a Internal teeth M1 Metal plate Ma1 Sagging Mb1 Shear surface w11 (radial clearance) gap width α1 radial clearance β1 circumferential clearance

Claims

1. A clutch unit comprising: an input side clutch that controls the transmission and interruption of torque input by lever operation; an output side clutch that is in a locked state to interrupt reverse input torque input to the output shaft when there is no lever operation; and a locking mechanism that restricts rotation of the output shaft at an axial position different from that of the output side clutch, wherein the locking mechanism restricts rotation of the output shaft by meshing external teeth of a first locking element that rotates integrally with the output shaft with internal teeth of a second locking element whose rotation around the axis of the output shaft is restricted, and wherein the meshed state between the external teeth and the internal teeth is released when the second locking element moves in the axial direction of the output shaft in response to lever operation, wherein the tooth width of the internal teeth of the second locking element is narrower than the tooth width of the external teeth of the first locking element.

2. A clutch unit as described in claim 1, wherein the external teeth are formed in association with punching the metal plate that serves as the base material of the first locking element, the internal teeth are formed in association with punching the metal plate that serves as the base material of the second locking element, and the first locking element and the second locking element are arranged so that when there is no lever operation, the ends of the external teeth and the internal teeth on the punching end side are positioned on the same plane.

3. A clutch unit as described in claim 1, wherein the first locking element has an integral cylindrical fixing portion that is fixed to the outer circumferential surface of the output shaft, and the fixing portion is not in contact with any member other than the first locking element in the axial direction.

4. A clutch unit comprising: an input side clutch that controls the transmission and interruption of torque input by lever operation; an output side clutch that enters a locked state to interrupt reverse input torque input to the output shaft when there is no lever operation; and a locking mechanism that restricts rotation of the output shaft at an axial position different from that of the output side clutch, wherein the locking mechanism maintains the locked state by meshing external teeth of a first locking element that rotates integrally with the output shaft with internal teeth of a second locking element whose rotation around the axis of the output shaft is restricted, and wherein the first locking element and the second locking element move relatively in the axial direction of the output shaft by lever operation to release the meshed state of the external teeth and the internal teeth, wherein the external teeth and the internal teeth mesh through a radial gap having a gap width of 0.2 to 0.4 mm.

5. A clutch unit as set forth in claim 4, wherein the tooth width of said external teeth is greater than the tooth width of said internal teeth.

6. A clutch unit as set forth in claim 4, wherein said external teeth and said internal teeth mesh with each other via a circumferential gap, the width of said circumferential gap being equal to or smaller than the width of said radial gap.

7. A clutch unit as described in claim 4, wherein the first locking element and the second locking element are press-punched parts made of metal plate, and the first locking element and the second locking element have shear surfaces whose lengths in the thickness direction of the metal plate are 70% or more of the thickness of the metal plate.

8. A clutch unit as described in claim 4, wherein the first locking element and the second locking element are press-punched parts made of metal plate, and the amount of sagging of the external teeth and the internal teeth at the tooth tips is 40% or less of the thickness of the metal plate, and the amount of sagging in areas other than the tooth tips is 20% or less of the thickness of the metal plate.

9. A clutch unit as described in claim 1 or 4, wherein the output side clutch comprises a stationary member whose rotation about the axis of the output shaft is restricted, and a roller disposed in a wedge gap formed between the output shaft and the stationary member, and the locked state is achieved by the roller engaging with the output shaft and the stationary member in the circumferential direction of the output shaft.

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