Clutch unit

Abstract

To strength the rotation regulation of an output shaft of a clutch unit.SOLUTION: A clutch unit 1 comprises: an input-side clutch 10 for controlling the transmission and block of torque which is inputted by a lever operation; an output-side clutch 20 brought into a lock state for blocking reverse input torque inputted to an output shaft 2 when the lever operation is not performed; and a lock mechanism 30 for regulating the rotation of the output shaft 2 in an axial position which is different from the output-side clutch 20. The lock mechanism 30 regulates the rotation of the output shaft 2 by the engagement of outer teeth 31b of a first lock element 31 which rotates integrally with the output shaft 2 and inner teeth 33a of a second lock element 32 which is regulated in rotation, and releases an engagement state of both the teeth 31b, 33a by the relative movement of the first lock element 31 and the second lock element 32 in an axial direction of the output shaft 2 by the lever operation. The outer teeth 31b and the inner teeth 33a are engaged with each other via a clearance α in a radial direction with a clearance width w set as 0.2 to 0.4 mm.SELECTED DRAWING: Figure 7

Description

[Technical field]

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

[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 side clutch that controls the transmission and cut-off of torque input by rotating an operating lever (hereinafter simply referred to as "lever operation"), an output side clutch consisting of a reverse input cut-off clutch, and an output shaft onto which the input side and output side clutches are fitted, and in which torque input from the input side clutch to the output side clutch releases the locked state (reverse input cut-off state) of the output side clutch, causing the output shaft to rotate around its axis.

[0003] More specifically, in the output clutch of the clutch unit, when there is no lever operation (torque input to the input clutch), the rollers as engagement elements arranged in the wedge gap formed between the outer peripheral surface of the output shaft (the inner ring spline-fitted to the output shaft) and the inner peripheral surface of the stationary member (outer ring) whose rotation is restricted are engaged with the inner ring and the outer ring (the inner ring and the outer ring are engaged in the circumferential direction of the output shaft), thereby entering a locked state in which the relative rotation of the inner ring and the outer ring, i.e., the rotation of the output shaft, is restricted. In this locked state, the reverse input torque input to the output shaft is not transmitted to the input clutch because the rotation of the output shaft is restricted. On the other hand, when torque is input from the input clutch to the output clutch in response to the lever operation, the rollers are pushed outward of the wedge gap, entering an unlocked state in which the relative rotation of the inner ring and the outer ring is permitted. In the unlocked state, the torque input from the input clutch is transmitted to the output shaft via the inner ring, causing the output shaft to rotate. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2017-109698 A Summary of the Invention [Problem to be solved by the invention]

[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 in the circumferential direction, but there is a possibility that a slight slippage may occur between the roller and the inner and / or outer ring, causing the output shaft to rotate unintentionally. If the slight slippage occurs in a clutch unit incorporated in a seat lifter for an automobile seat (particularly the driver's seat), the seat surface may suddenly drop, making it impossible to maintain an appropriate driving position, which may cause driving problems. Therefore, it is necessary to strengthen the restriction of the rotation of the output shaft when the operating lever is not being operated.

[0006] Therefore, the present invention aims to strengthen the rotation regulation of the output shaft when the operating lever is not operated in a clutch unit that has an input side clutch that controls the transmission and cut-off of torque input by lever operation, and an output side clutch consisting of a reverse input cut-off clutch. [Means for solving the problem]

[0007] The present invention, which has been devised to achieve the above object, an input clutch that controls transmission and interruption of torque input by lever operation; an output side clutch that is in a locked state to block 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 that of the output side clutch, The lock mechanism is a clutch unit in which external teeth of a first locking element, which rotates integrally with the output shaft, mesh with internal teeth of a second locking element, whose rotation about the axis of the output shaft is restricted, thereby restricting rotation of the output shaft, and in which the meshed state of the external teeth and the internal teeth is released by operating a lever to move the first locking element and the second locking element relatively in the axial direction of the output shaft, The external teeth and internal teeth are characterized in that they mesh with each other via a radial gap having a gap width of 0.2 to 0.4 mm.

[0008] In the clutch unit having the above configuration, since a lock mechanism that restricts the rotation of the output shaft at an axial position different from the output-side clutch when the lever is not operated is additionally provided, the rotation restriction of the output shaft can be strengthened, and the possibility of the output shaft rotating unexpectedly can be effectively reduced. In particular, in the lock mechanism having the above configuration, if the external teeth and the internal teeth are meshed with each other through a radial gap with a gap width in the range of 0.2 to 0.4 mm, the function of strengthening the restriction on the rotation of the output shaft can be appropriately exhibited.

[0009] In the above configuration, the tooth width (axial dimension) of the external teeth is preferably larger than the tooth width of the internal teeth.

[0010] In the above configuration, the external teeth and the internal teeth preferably mesh with each other via a circumferential gap, and in this case, the width of the circumferential gap is preferably equal to or smaller than the width of the radial gap.

[0011] In the above configuration, the first and second locking elements can be press-punched parts of a metal plate. This can suppress an increase in cost of the clutch unit in which a locking mechanism is additionally provided. In this case, both locking elements have a shear surface whose length in the thickness direction of the metal plate is 70% or more of the thickness of the metal plate. This can improve the meshing accuracy of the first locking element and the second locking element. For the same reason, it is preferable that the external teeth of the first locking element and the internal teeth of the second locking element, which are press-punched parts, have a sagging amount at the tooth tip of 40% or less of the thickness of the metal plate and a sagging amount in the area other than the tooth tip of 20% or less of the thickness of the metal plate.

[0012] In the above configuration, the output side clutch that constitutes 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 disposed 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 is locked when the roller engages with the output shaft and the stationary member in the rotational direction of the output shaft. Effect of the Invention

[0013] From the above, according to the present invention, it is possible to strengthen the rotation regulation of the output shaft in a clutch unit that has an input side clutch that controls the transmission and cut-off of torque input by lever operation, and an output side clutch consisting of a reverse input cut-off clutch. [Brief description of the drawings]

[0014] [Figure 1] FIG. 2 is a schematic vertical cross-sectional view of the clutch unit according to the embodiment of the present invention, showing a state where the lever is not operated. [Diagram 2] FIG. 2 is a cross-sectional view taken along the line A in FIG. [Diagram 3] FIG. 2 is a cross-sectional view taken along the line B in FIG. [Figure 4] 2 is a cross-sectional view of the clutch unit taken along the line A in FIG. 1 when a lever is operated. [Diagram 5] 2 is a cross-sectional view of the clutch unit taken along the line B in FIG. 1 when a lever is operated. [Figure 6] FIG. 2 is an exploded perspective view of a portion of the clutch unit shown in FIG. [Figure 7] 1A and 1B are plan and side views of a locking mechanism in a locked position. [Figure 8] 1A and 1B are plan and side views of a locking mechanism in an unlocked position. [Figure 9] FIG. 4 is a schematic vertical cross-sectional view of the locking mechanism when the lever is operated. [Figure 10] FIG. 1A is a perspective view conceptually showing the state of a processed surface of a metal plate that has been subjected to press punching, and FIG. 1B is a schematic cross-sectional view of the metal plate shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, an embodiment of the present invention will be described with reference to FIGS.

[0016] FIG. 1 is a schematic vertical cross-sectional view of a clutch unit 1 according to an embodiment of the present invention, showing a state where an operating lever is not operated (when the operating lever is in a neutral position). The clutch unit 1 is used, for example, by being incorporated into a seat lifter for adjusting the height of a seat surface of an automobile seat, and includes an output shaft 2 rotatably provided around an axis X, a housing 3, an operating lever 4, an input clutch 10, an output clutch 20, and a mechanical lock mechanism 30. In the following description, the terms "axial direction," "radial direction," and "circumferential direction" used to indicate directionality are respectively 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. In the following description, "rotation" refers to rotation around the axis X of the output shaft 2, unless otherwise specified.

[0017] The output shaft 2 includes a small diameter section 2a having a cylindrical outer circumferential surface with a constant diameter, a spline section 2b on which a spline (male spline) is formed, a large diameter section 2c having a cylindrical outer circumferential surface with a larger diameter than the small diameter section 2a, and a gear section 2d on which a gear is formed. The small diameter section 2a, the spline section 2b, the large diameter section 2c, and the gear section 2d are arranged in 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).

[0018] The housing 3 is integrally formed with a stepped cylindrical portion having a small diameter cylindrical portion 3a fitted to 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 an attachment flange 3d (see FIG. 2, etc.) provided on the opening edge of the large diameter cylindrical portion 3c. The attachment flange 3d is provided with bolt holes through which bolt members are inserted when the housing 3 (clutch unit 1) is bolted to an attachment target such as an external frame. In addition, a disk-shaped portion of the housing 3 connecting the small diameter cylindrical portion 3a and the medium diameter cylindrical portion 3b is provided with a plurality of (three in this case, see FIG. 2) pillar portions 3e that protrude to the output side and are disposed in the annular space of the input clutch 10 at equal intervals in the circumferential direction. The pillar portions 3e divide the annular space into arc-shaped spaces and define the circumferential movement limit of the engagement element of the input clutch 10.

[0019] 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 pieces and elastic members disposed between the inner ring 11 and the outer ring 13. The engaging pieces and elastic members in the illustrated example are rollers 14 and coil springs 15, respectively. The inner ring 11 and the outer ring 13 are rotatably fitted to the outer periphery of the small diameter portion 2a of the output shaft 2.

[0020] The operating lever 4 has a lever body 5 and an operating plate 6. The lever body 5 has, integrally, a bottomed cylindrical housing portion 5A that houses the input clutch 10 and the lock mechanism 30, and a grip portion 5B that is gripped by an operator (such as a driver of a car).

[0021] As shown in Fig. 6, the operation plate 6 is a disk-shaped member having a non-circular central hole 6a, and is rotatably supported with respect to the small diameter cylindrical portion 3a of the housing 3 via a cylindrical support bush 7 or the like inserted into the central hole 6a so as to be unable to rotate relative to the housing. The operation plate 6 further has a lever attachment 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 at equal intervals in the circumferential direction radially outside the central hole 6a. The holes 6c are formed in the shape of elongated holes extending in the circumferential direction.

[0022] 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. This inner ring 11 has a convex portion 11a that protrudes towards 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.

[0023] 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) of 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 end 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 do not rotate together with the operation lever 4 until the operation lever 4 rotates a predetermined amount (until the rotation restriction of the output shaft 2 by the lock mechanism 30 is released by the operation lever 4 rotating a predetermined amount. The lock mechanism 30 will be described in detail later).

[0024] 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 to 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 there is no torque input by lever operation.

[0025] 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 includes 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.

[0026] An annular space is defined between the outer peripheral surface of the inner ring 11 and the inner peripheral surface of the large-diameter cylindrical portion 13a of the outer ring 13 facing the inner peripheral surface, and this annular space is divided into three arc-shaped spaces 16 by three pillar portions 3e provided on the housing 3. 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 are incorporated in each arc-shaped space 16. The arc-shaped space 16 has an equal-width portion 16a having a constant radial width 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 and whose radial width gradually decreases toward the outside in the circumferential direction of the arc-shaped space 16. When no torque is input to the inner ring 11 by lever operation (FIG. 2), the wedge-shaped portions 16b are provided on both circumferential sides of the equal-width portion 16a.

[0027] 2, when no torque is input to the inner ring 11, the pair of rollers 14 are pressed into the wedge-shaped portion 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 with both the inner ring 11 and the outer ring 13 in the circumferential direction). This restricts the relative rotation between the inner ring 11 and the outer ring 13.

[0028] On the other hand, for example, as shown in Fig. 4, when the torque T for rotating the inner ring 11 counterclockwise is input to the inner ring 11 by rotating the operating lever 4 in one direction, the wedge portion 11c of the inner ring 11 abuts against the roller 14 (14B) disposed adjacently on the front side in the rotation direction and presses the roller 14B in the circumferential direction. Accordingly, the roller 14B moves counterclockwise in the arc-shaped space 16 while compressing and deforming the coil spring 15, while the roller 14A is restricted in its circumferential movement by the column portion 3e of the housing 3. The roller 14B, which is directly subjected to the pressing force of the inner ring 11, moves counterclockwise in 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 the relative rotation between them, so that the outer ring 13 also rotates counterclockwise together with the inner ring 11.

[0029] When the inner ring 11 rotates clockwise after rotating counterclockwise by a predetermined amount (torque input to rotate the inner ring 11 clockwise), the roller 14B leaves 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 rotates clockwise among the inner ring 11 and the outer ring 13 (the inner ring 11 rotates freely relative to the outer ring 13). In addition, the roller 14B receives an elastic restoring force accumulated in the coil spring 15 and moves clockwise in the arc-shaped space 16 to follow the rotation of the inner ring 11. When the inner ring 11 rotates clockwise by a predetermined amount, the input side clutch 10 returns to the initial state shown in FIG. 2.

[0030] 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, the wedge portion 11c of the inner ring 11 presses the roller 14A arranged adjacent to it on the front side in the rotation 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 side clutch 10 returns to the initial state.

[0031] Next, the output clutch 20 will be described mainly with reference to Fig. 1, Fig. 3, and Fig. 5 to Fig. 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 the reverse input cutoff clutch, includes an unlocking member 21 that rotates upon receiving torque input from the input clutch 10 (the outer ring 13 that is the output side rotating member), an inner ring 22 that rotates upon receiving torque of 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 arranged 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.

[0032] The unlocking member 21 is a disk-shaped member fitted to 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 together with the outer ring 13, and constitutes an 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 portion 21b is provided at the outer diameter end thereof, protruding to the output side and disposed radially outside the inner ring 22 (within the annular space 26 defined between the inner ring 22 and the outer ring 23). In this embodiment, as shown in Figs. 3 and 5, six holes 21a and claw portions 21b are provided at equal intervals in the circumferential direction. The hole 21a is formed in the shape of an elongated hole extending in the circumferential direction.

[0033] 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 at equal intervals in the circumferential direction. Each of the convex portions 22a is inserted into an elongated hole portion 21a provided 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 portion 21a (see FIG. 3).

[0034] 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 circumference, 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 side end of the large diameter cylindrical portion 23a and the input side 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 circumference of the small diameter cylindrical portion 23b, and the inner peripheral surface of this friction ring 27 is in pressure contact with the large diameter portion 2c of the output shaft 2. This makes it possible to apply rotational resistance to the output shaft 2, thereby preventing the output shaft 2 from rotating excessively when the operating lever 4 is rotated.

[0035] 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 that are arranged at equal circumferential intervals within the annular space. In each arc-shaped space 26, a pair of rollers 24 (24A, 24B) arranged at an interval in the circumferential direction and a coil spring 25 interposed between the pair of rollers 24 in a circumferentially compressed and deformed state are incorporated.

[0036] The arc-shaped space 26 is formed in a wedge shape with a radial width gradually decreasing from the circumferential center toward both circumferential ends. The arc-shaped space 26 as a wedge gap 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, the outer circumferential surface of the inner ring 22 is formed into a non-circular cross section by continuously arranging six wedge-shaped portions 22b protruding radially outward in the circumferential direction, and the wedge-shaped arc-shaped space 26 is formed between two wedge-shaped portions 22b adjacent in the circumferential direction. 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.

[0037] For this reason, when the operating lever 4 is not rotated and no torque is input from the input clutch 10 to the lock release 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 the relative rotation in both directions of the inner ring 22 with respect to the outer ring 23, and further, the rotation of the output shaft 2, is restricted. In this locked state, even if a reverse input torque is input to the output shaft 2, the reverse input torque is not transmitted to the input clutch 10.

[0038] On the other hand, as shown in Fig. 5, for example, when the operating lever 4 is rotated in one direction to input a torque T to the unlocking member 21 via the input clutch 10 to rotate the unlocking member 21 counterclockwise, the claws 21b of the unlocking member 21 move counterclockwise in the annular space (arc-shaped space 26) between the inner ring 22 and the outer ring 23. As a result, each claw 21b comes into contact with the roller 24 (roller 24B in Fig. 5) adjacently disposed on the front side in the moving direction, and presses 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 arc-shaped space 26 where it is engaged with both the inner ring 22 and the outer ring 23, and the engagement state (lock state) between the roller 24B and the inner ring 22 and the outer ring 23 in the circumferential direction is released. Even if a counterclockwise torque T is input to the lock release member 21, the roller 24A does not engage with the inner ring 22 and the outer ring 23 and rotates freely.

[0039] Furthermore, when the unlocking member 21 rotates counterclockwise, the convex portion 22a of the inner ring 22 inserted into the hole portion 21a of the unlocking member 21 abuts against the peripheral end of the hole portion 21a, as shown in Fig. 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 body. Therefore, when the unlocking member 21 further rotates counterclockwise, the roller 24 and the coil spring 25 between the inner and outer rings 22 and 23 move circumferentially counterclockwise, and the inner ring 22 and the rotating shaft 2 rotate counterclockwise. As a result, a counterclockwise torque is output from the rotating shaft 2.

[0040] When torque is input to rotate the unlocking member 21 clockwise, the roller 24B receives a pressure force caused by 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 a locked state in which reverse input torque is blocked.

[0041] Next, the lock mechanism 30 will be described mainly with reference to Fig. 1 and Fig. 6 to Fig. 9. The lock mechanism 30 is disposed on the input side of the input clutch 10, and restricts the rotation of the output shaft 2 when the operating lever 4 is not operated (when the operating lever 4 is in the neutral position). The lock mechanism 30 includes a first lock element 31 provided so as to be rotatable together with the output shaft 2, a second lock element 32 disposed radially outward of the first lock element 31 and whose rotation is restricted, an elastic member 35, and an unlocking member 36.

[0042] The first locking element 31 has an annular male gear portion 31a with a plurality of external teeth 31b formed at equal intervals in the circumferential direction 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 2a of the output shaft 2. The first locking element 31 in this form 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 31b 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 2.

[0043] The second locking element 32 has an annular female gear portion 33 having internal teeth 33a formed at an inner diameter end (inner peripheral surface) at equal intervals in the circumferential direction and capable of meshing with the external teeth 31b of the first locking element 31, and a gear support portion 34 formed as a separate member from the female gear portion 33 and fixedly supporting the female gear portion 33. As with the first locking element 31, the female gear portion 33 is obtained by subjecting a metal plate of a predetermined thickness to press punching.

[0044] The tooth width of the external teeth 31b of the first locking element 31 (which can also be said to be the axial width of the male gear portion 31a, or the thickness of the metal plate that is the base material of the first locking element 31) is within a range of 1.2 mm to 3.0 mm, and the tooth width of the internal teeth 33a (which can also be said to be the axial width of the female gear portion 33, or the thickness of the metal plate that is the base material of the male gear portion 33) is within a range of 0.6 mm to 1.6 mm, which is smaller than the tooth width of the external teeth 31b. As a specific example, the tooth width of the external teeth 31b can be 2.0 mm, and in this case, the tooth width of the internal teeth 33a is 0.8 mm, taking into consideration the balance between the weight and strength of the female gear portion 33. The reason why the tooth width of the external teeth 31b is made larger than the tooth width of the internal teeth 33a is that (1) The first locking element 31 having the external teeth 31b integrally therewith can be firmly fixed to the outer circumferential surface of the output shaft 2 which is a rotating shaft, (2) In order to enable the external teeth 31b and the internal teeth 33a to mesh properly, In other words, with regard to (2) above, if the face widths of both are the same, a sufficient meshing length cannot be ensured unless the axial arrangement positions of both are aligned.

[0045] The gear support portion 34 is a stepped cylindrical member having a small diameter cylinder portion 34a that is fitted to the outer periphery of the support bush 7, and a flange portion 34b provided at the end on the input side fixedly supports the male gear portion 33. As shown in FIG. 6, the small diameter cylinder portion 34a has a plurality (three) of notches 34c that are equally spaced in the circumferential direction, and the outer circumferential surface of the flange portion 34b has a plurality (three) of protruding pieces 34d that protrude radially outwardly that are equally spaced in the circumferential direction. The protruding portion 7a that is provided on the outer circumferential surface of the support bush 7 so as to protrude to the outer diameter side is fitted into the notches 34c of the gear support portion 34 via a small gap. As a result, the gear support portion 34 (including the second lock element 32) is restricted from rotating relative to the support bush 7, and is supported by the support bush 7 in a state in which it can move linearly in the axial direction.

[0046] The elastic member 35 is interposed between the male gear portion 31b of the first locking element 31 and the gear support portion 34 of the second locking element 32 in an axially compressed state, and constantly biases the second locking element 32 toward the output side. As this elastic member 35, a wave washer as shown in Fig. 6, or a compression coil spring, etc., can be used.

[0047] The unlocking member 36 is a cylindrical member that houses the second locking element 32 (the gear support portion 34) on its inner circumference, and is fitted and fixed in the central hole 6a of the operation plate 6 so as to be rotatable integrally with the operation plate 6. The unlocking member 36 has recesses 36a that can individually house the three protruding pieces 34d provided on the flange portion 34b of the gear support portion 34, and each recess 36a is defined between protruding portions 36b provided on both sides in the circumferential direction. The recesses 36a and the protruding portions 36b are connected via an inclined surface that forms an angle with respect to an axis-parallel plane that is parallel to the axis center X (see the side view shown in FIG. 7).

[0048] 1 and 7, when the operating lever 4 is in the neutral position, the protruding piece 34d of the gear support portion 34 constituting the second locking element 32 is housed in the recess 36a of the lock release member 36. At this time, in the lock mechanism 30, the male gear portion 31a (the external teeth 31b) of the first locking element 31 which is rotatable integrally with the output shaft 2 meshes with the female gear portion 33 (the internal teeth 33a) of the second locking element 32 whose rotation is restricted. This restricts the rotation of the output shaft 2.

[0049] Next, when the operating lever 4, which was in the neutral position, is rotated in one circumferential direction, the unlocking member 36, which is fixed to the operating plate 6 of the operating lever 4 so as to be rotatable together with the operating plate 6, also rotates. On the other hand, since the rotation of the gear support portion 34 of the second locking element 32 is restricted, when the unlocking member 36 rotates, the protruding piece 34d of the gear support portion 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 circumferential outer side of the recess 36a, as shown in Fig. 8. Accordingly, the second locking element 32 moves overall to the input side while compressing and deforming the elastic member 35 interposed between the first locking element 31 and the second locking element 32 in the axial direction, and the female gear portion 33 (the internal teeth 33a) is positioned closer to the input side than the male gear portion 31a (the external teeth 31b) as shown in Fig. 9. As a result, the meshed state between the male gear portion 31a and the female gear portion 33, that is, the restriction on rotation of the output shaft 2 by the lock mechanism 30, is released.

[0050] In addition, even if a rotation operation (rotation operation toward the other circumferential side) is performed to return the operating lever 4 to the neutral position, in the lock mechanism 30 configured as described above, the external teeth 31b of the male gear portion 31a constituting the first lock element 31 and the internal teeth 33a of the female gear portion 33 of the second lock element 32 do not necessarily re-mesh, and there is a possibility that they do not mesh due to a phase shift between the external teeth 31b and the internal teeth 33a. Even if the external teeth 31b and the internal teeth 33a do not mesh due to the above-mentioned phase shift, the first lock element 31 fixed to the output shaft 2 also rotates together with the output shaft 2 as the output shaft 2 rotates (slightly) due to minute slippage generated in the output-side clutch 20 due to vehicle vibration or the like. Then, the external teeth 31b mesh with the internal teeth 33a due to this rotation, and the rotation of the output shaft 2 is restricted by the lock mechanism 30.

[0051] The individual operating modes of the input clutch 10, the output clutch 20, and the lock 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.

[0052] For example, when the operating lever 4, which was in the neutral position, is rotated counterclockwise, first, torque is input to the lock release member 36 constituting the lock mechanism 30. As a result, the second lock element 32 of the lock mechanism 30 moves axially toward the output side, and the meshed state between the male gear portion 31a of the first lock element 31, which rotates integrally with the output shaft 2, and the female gear portion 33 of the second lock element 32, whose rotation has been restricted, is released (see FIG. 9). As a result, the rotation restriction of the output shaft 2 by the lock mechanism 30 is released, and the output shaft 2 becomes rotatable.

[0053] When the operating lever 4 is further rotated counterclockwise, as shown in FIG. 4, a torque T is input to the inner ring 11 of the input clutch 10 to rotate the inner ring 11 counterclockwise. The wedge portion 11c of the inner ring 11 to which the torque T is input abuts against the roller 14 (14B) disposed adjacently on the front side in the rotation direction, and presses the roller 14B in the circumferential direction. As a result, the roller 14B moves counterclockwise in the arc-shaped space 16 while compressing and deforming the coil spring 15. The roller 14B, which is directly subjected to the pressing force of the inner ring 11, moves counterclockwise in the arc-shaped space 16 while being pressed into the wedge portion 16b of the arc-shaped space 16, that is, while being engaged with both the inner ring 11 and the outer ring 13 and restricting the relative rotation between them, so that 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.

[0054] As described above, when the outer ring 13, which is the output side rotating member of the input clutch 10, rotates counterclockwise, as shown in FIG. 5, a torque T that rotates the unlocking member 21, which is the input side rotating member of the output clutch 20, counterclockwise is input. Accordingly, the claw portion 21b of the unlocking member 21 arranged in the arc-shaped space 26 between the inner ring 22 and the outer ring 23 moves counterclockwise and abuts against the roller 24 (roller 24B in FIG. 5) adjacently arranged on the front side in the moving direction, and presses the roller 24B in the circumferential direction. This releases the circumferential engagement state between the roller 24B and the inner ring 22 and the outer ring 23, that is, the locked state in which the transmission of the reverse input torque input to the output shaft 2 to the input clutch 10 is interrupted. Of the pair of rollers 24 (24A, 24B), the roller 24A rotates idly without engaging with the inner ring 22 and the outer ring 23 even when the counterclockwise torque T is input to the unlocking member 21.

[0055] Furthermore, when counterclockwise torque T is input to the unlocking member 21, the protrusion 22a of the inner ring 22 inserted into the hole 21a of the unlocking member 21 abuts against the circumferential end of the hole 21a. As a result, the inner ring 22, which is the output-side rotating member of the output-side clutch 20, and the output shaft 2 spline-fitted with the inner ring 22 rotate counterclockwise as one unit in response to the counterclockwise torque T input to the unlocking member 21.

[0056] As described above, in the clutch unit 1 of this embodiment, when there is no lever operation (when the operating lever 4 is not rotated), the locking mechanism 30 is additionally provided to restrict rotation of the output shaft 2 at an axial position different from the output side clutch 20 (on the input side of the input side clutch 10), so that the restriction on rotation of the output shaft 2 can be strengthened, thereby reducing the possibility of the output shaft 2 rotating unexpectedly.

[0057] In the lock mechanism 30 of this embodiment, the external teeth 31b of the first lock element 31, which rotates integrally with the output shaft 2, mesh with the internal teeth 33a of the second lock element 32, the rotation of which is restricted, thereby restricting the rotation of the output shaft 2, and the meshed state between the external teeth 31b and the internal teeth 33a is released by moving the second lock element 32 to the input side by operating a lever. In this case, as shown in the enlarged view of Fig. 7, if the gap width w (in other words, the meshing allowance between the teeth) of the radial gap α formed between the external teeth 31b (tooth tips 37) and the internal teeth 33a (tooth bottoms 38) is not controlled within an appropriate range, various problems may occur.

[0058] Specifically, when the gap width w of the radial gap α is large and the meshing allowance between the teeth 31b and 33a is small (specifically, when w>0.4 mm), the allowable torque is reduced, and it may not be possible to appropriately regulate the rotation of the output shaft 2. In addition, the meshing surface pressure increases, and one or both of the male gear portion 31a of the first locking element 31 and the female gear portion 33 of the second locking element 32 may be damaged. Conversely, when the gap width w of the radial gap α is small and the meshing allowance between the teeth 31b and 33a is large (specifically, when w<0.2 mm), it becomes difficult to tolerate even a slight misalignment between the male gear portion 31a and the female gear portion 33 resulting from the dimensional tolerances of each component, and it becomes difficult to realize an appropriate meshed state and non-meshed state between the teeth 31b and 33a (locked state and unlocked state of the locking mechanism 30). Therefore, the gap width w of the radial gap α is controlled within a range of 0.2 mm to 0.4 mm, thereby making it possible to appropriately realize and maintain the state in which the rotation of the output shaft 2 is restricted.

[0059] When the clutch unit 1 of this embodiment is used by being incorporated into a seat lifter for an automobile, the tooth height (total tooth height) of the teeth 31b, 33a is selected to be within a range of 7 mm to 15 mm for the male gear portion 31 and the female gear portion 33. If the tooth height is too small, the allowable torque will be insufficient, whereas if the tooth height is too large, the weight will increase and the allowable torque will be excessive.

[0060] As shown in the enlarged view of FIG. 7, the width of the circumferential gap β formed between the circumferential end faces of the external teeth 31b and the internal teeth 33a is preferably equal to or smaller than the width of the radial gap α. If the width of the circumferential gap β is too large, the circumferential backlash during locking may become large, which may cause discomfort and anxiety to the passengers (operators) of the vehicle. Strictly speaking, the width of the circumferential gap β referred to here is the width of the circumferential gap β formed between the circumferential end faces of the external teeth 31b and the internal teeth 33a when the external teeth 31b are positioned in a neutral position (a position where the circumferential center of the external teeth 31b coincides with the circumferential center of the recess formed between two adjacent internal teeth 33a). Furthermore, assuming that the gap width of the circumferential gap β formed at one circumferential end face of the external tooth 31b is z1 and the gap width of the circumferential gap β formed at the other circumferential end face of the external tooth 31b is z2, the value is calculated using the formula gap width = (z1 + z2) / 2.

[0061] In this embodiment, the first locking element 31 having the external teeth 31b and the female gear portion 33 of the second locking element 32 having the internal teeth 33a are formed as parts punched out of a metal plate, thereby suppressing the manufacturing costs of both locking elements 31, 32, and thus the increase in the cost of the clutch unit 1 in which the locking mechanism 30 is additionally provided.

[0062] Incidentally, when a press punching process is performed from the front side to the back side of a metal plate, as shown in Fig. 10(a), sagging Ma, sheared surfaces Mb, and fractured surfaces Mc are formed in this order on the punched surface of the metal plate M, and further, burrs Md are generally formed. The sagging Ma is an R-shaped smooth surface formed by pulling the surface of the metal plate M with a press die, the sheared surfaces Mb are smooth surfaces with visible streaks in the plate thickness direction (press direction), the fractured surfaces Mc are rough surfaces (uneven surfaces) as if a part of the material had been torn off, and the burrs Md are protrusions protruding outward in the plate thickness direction of the metal plate M from the back side of the metal plate M. The sagging Ma, sheared surfaces Mb, fractured surfaces Mc, and burrs Md that may appear (or may not appear) on the punched surface of the metal plate M can be removed by a separate finishing process such as grinding and polishing, but an increase in cost due to the additional processing steps is unavoidable.

[0063] Therefore, it is preferable that the female gear portion 33 constituting the first locking element 31 and the second locking element 32 is a press-punched part having the above-mentioned sheared surface Mb, that is, a press-punched part having a punched surface in which finishing and the like are omitted and the surface state obtained by punching is maintained. In this case, however, as shown in Fig. 10(b), a press-punched part in which the length d1 of the sheared surface Mb in the thickness direction of the metal plate M is 70% or more of the thickness d of the metal plate M is used for the male gear portion 33 of the first locking element 31 and the second locking element 32. This improves the meshing accuracy of the external teeth 31b of the first locking element 31 and the internal teeth 33a of the second locking element 32 (reducing the possibility of poor meshing between the external teeth 31b and the internal teeth 33a), and the rotation restriction of the output shaft 2 by the locking mechanism 30 can be appropriately realized.

[0064] In addition, when the portions with continuous minute irregularities such as the external teeth 31b of the first locking element 31 and the internal teeth 33a of the second locking element 32 (female gear portion 33 constituting the second locking element 32) are formed by punching, the amount of sagging (length of sagging Ma) d2 in the thickness direction of the metal plate M tends to increase. As the amount of sagging increases, the length d1 of the shear surface Mb becomes relatively shorter, making it difficult to mesh the teeth with high precision. For this reason, it is preferable that the amount of sagging d2 of the external teeth 31b of the first locking element 31 and the internal teeth 33a of the male gear portion 33 is 40% or less of the sheet thickness d of the metal plate M at the tooth tips (portions that mesh with the teeth of the mating side) and 20% or less in the region excluding the tooth tips. This improves the meshing precision of the outer peripheral tooth surface 31b of the first locking element 31 and the inner peripheral tooth surface 33a of the second locking element 32, and effectively restricts the rotation of the output shaft 2 by the locking mechanism 30.

[0065] Although the clutch unit 1 according to the embodiment of the present invention has been described above, appropriate modifications can be made to the clutch unit 1 without departing from the gist of the present invention. For example, the output clutch 20 can be configured with a clutch other than the roller clutch described above.

[0066] The present invention is not limited to the above-described embodiment, and can be embodied in various other forms without departing from the spirit of the present 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. [Explanation of symbols]

[0067] 1 Clutch unit 2 Output shaft 3. Housing 4 Operating lever 5 Lever body 6 Operation board 7 Support bush 10 Input clutch 20 Output clutch 30 Locking mechanism 31 First locking element 31b External teeth 32 Second locking element 33a Internal teeth M Metal plate Ma who Mb Shear surface w (radial clearance) gap width α Radial clearance β Circumferential clearance

Claims

1. an input clutch that controls transmission and interruption of torque input by lever operation; an output side clutch that is in a locked state to block 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, The lock mechanism is a clutch unit that 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 about the axis of the output shaft is restricted, and releases the meshed state between the external teeth and the internal teeth by moving the first locking element and the second locking element relatively in the axial direction of the output shaft by a lever operation, The clutch unit is characterized in that the external teeth and the internal teeth mesh with each other via a radial gap having a gap width of 0.2 to 0.4 mm.

2. 2. The clutch unit according to claim 1, wherein a tooth width of said external teeth is greater than a tooth width of said internal teeth.

3. The external teeth and the internal teeth mesh with each other via a circumferential gap, 2. The clutch unit according to claim 1, wherein the width of the circumferential gap is equal to or smaller than the width of the radial gap.

4. the first locking element and the second locking element are stamped parts made of a metal plate, 2. The clutch unit according to claim 1, wherein the first locking element and the second locking element have a shear surface whose length in the thickness direction of the metal plate is 70% or more of the thickness of the metal plate.

5. the first locking element and the second locking element are stamped parts made of a metal plate, 2. The clutch unit according to claim 1, wherein the amount of sagging at the tips of the external teeth and the internal teeth is 40% or less of the thickness of the metal plate, and the amount of sagging in the area excluding the tips of the teeth is 20% or less of the thickness of the metal plate.

6. 2. The clutch unit according to claim 1, 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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