JP7522337B2 - Brake device and manufacturing method thereof - Google Patents

Description

The present invention relates to a brake device used in the height adjustment mechanism of a vehicle seat and a method for manufacturing the same.

The height adjustment mechanism for vehicle seats rotates an output shaft by operating a lever on the input side that swings the seat up and down, but a brake device is used that is configured to prevent the output shaft from rotating even if a force that tries to lower the seat due to the weight of the seat and occupant is applied to the output shaft.

For example, the brake device of Patent Document 1 includes an outer ring having a cylindrical inner peripheral surface, a plurality of brake shoes facing the inner peripheral surface, and an output-side rotating member arranged inside the brake shoes. When a rotational force is input to the output-side rotating member, the output-side rotating member presses the brake shoes against the inner peripheral surface of the outer ring, generating a frictional force between the inner peripheral surface and the brake shoes, preventing the output-side rotating member and the brake shoes from rotating. On the other hand, when a rotational force is input to the input-side rotating member that engages with the brake shoes in the rotational direction, the brake shoes and the output-side rotating member can be rotated.
The outer ring was then fixed to the mounting plate by laser welding.

JP 2016-124526 A

However, when the outer ring is fixed to the mounting plate by laser welding, the heat generated during welding causes distortion in the outer ring. In a brake device such as that described in Patent Document 1, if the inner peripheral surface of the outer ring is not round enough, there is a risk that the braking force will not be properly exerted.

The present invention has been made in view of the above background, and has an object to provide a brake device in which distortion of the inner peripheral surface of the ring is small and the ring is firmly fixed to the plate.
Another object of the present invention is to provide a method for manufacturing a device in which a ring is fixed to a plate by laser welding, whereby the ring is firmly fixed to the plate with minimal distortion of the cylindrical inner peripheral surface of the ring.

In order to achieve the above-mentioned object, the brake device of the present invention is a brake device comprising: a ring having a cylindrical inner surface and a side surface facing the axial direction of the inner surface; a plate having a first surface to which the side surface of the ring is fixed by laser welding and a second surface opposite the first surface; a shaft arranged inside the inner surface; and a brake mechanism capable of forming a brake state in which the shaft does not rotate relative to the ring, and a released state in which the shaft rotates.
The plate has, on the second surface, at a position overlapping with the ring when viewed in the axial direction, dot-like first weld marks spaced at equal angular intervals circumferentially on the inner surface, and circular second weld marks extending along the circumferential direction, and the number of first weld marks is four or more.

In this type of brake device, the ring and plate are fixed together without heat accumulation by four or more dot-like first weld marks, and the ring and plate are firmly fixed together by the circular second weld marks. This makes it possible to provide a brake device in which the distortion of the cylindrical inner surface of the ring is small and the ring is firmly fixed to the plate.

In the above-mentioned brake device, it is desirable that there are six or more first weld marks.

In order to achieve the above-mentioned object, a manufacturing method for a device of the present invention is a device comprising a ring having a cylindrical inner surface and a side surface facing the axial direction of the inner surface, and a plate having a first surface and a second surface opposite the first surface, in which the side surface of the ring is fixed to the first surface of the plate by laser welding.
This manufacturing method includes a positioning step of positioning the ring on the plate with the side of the ring in contact with the first surface; a first welding step of irradiating four or more positions spaced at equal angular intervals circumferentially on the inner surface with a laser at positions on the second surface that overlap with the ring when viewed from the axial direction, thereby laser welding them in a spot pattern, and a second welding step of irradiating the second surface with a laser continuously along the circumferential direction, thereby laser welding them in a circular pattern, thereby permanently fixing the ring to the plate.

According to the manufacturing method of such a device, in the first welding process, a laser is irradiated to four or more positions spaced at equal angular intervals around the circumferential direction of the inner circumferential surface to perform spot laser welding, so that the ring and the plate are temporarily fixed in place without heat accumulating. After this temporary fixing, the ring and the plate are laser welded in a circular shape in the second welding process, so that the ring can be firmly fixed to the plate with minimal distortion on the inner circumferential surface of the ring.

According to the brake device of the present invention, it is possible to reduce distortion of the cylindrical inner peripheral surface of the ring.
Furthermore, according to the method for manufacturing the device of the present invention, the ring can be firmly fixed to the plate with only a small distortion on the cylindrical inner peripheral surface of the ring.

FIG. 2 is a side view of the vehicle seat. FIG. FIG. 4 is a view of the outer ring and the mounting plate as viewed from the output side in the axial direction. FIG. 4A is an enlarged view of the vicinity of the inner surface of the brake shoe, and FIG. 4B is an enlarged view of the vicinity of the opposing surface of the output side rotating member. 5A is a cross-sectional view of the clutch unit taken along line ZZ in FIG. 4, and FIG. 5B is a cross-sectional view of the clutch unit taken along line YY in FIG. FIG. 4 is a view of the input side rotating member as viewed from the output side. FIG. 4 is a view of the friction member as viewed from the input side. FIG. 4 is a perspective view of the clutch unit as viewed from the cover member side. FIG. 2A is a cross-sectional view of the ratchet device, and FIG. 2B is an enlarged view of a protrusion. 11A and 11B are diagrams illustrating the operation of the ratchet device, showing the case where the operation input member is rotated clockwise. 11A and 11B are diagrams illustrating the operation of the ratchet device, showing the case where the operation input member is returned counterclockwise. 10 is a diagram for explaining the operation of the brake device, showing the case where a clockwise rotational torque is applied to the output side rotating member. FIG. 14 is a diagram for explaining the operation of the brake device, showing the case where a counterclockwise rotational torque is applied to the input side rotating member from the state of FIG. 13 . 14 is a diagram for explaining the operation of the brake device, showing a case where a clockwise rotational torque is applied to the input side rotating member from the state of FIG. 13 . 16 is a diagram for explaining the operation of the brake device, showing a state in which the input side rotating member has been further rotated clockwise from the state in FIG. 15 . 10A and 10B are diagrams for explaining the operation of the brake device, showing a state in which an excessive rotational torque in the clockwise direction is applied to the output side rotating member. FIG. 2 is a plan view of the laser welding machine. 1A is a plan view showing a state in which an outer ring and a mounting plate are fixed to a laser welding machine, and FIG. 1 is a table showing the amount of change in roundness of the inner circumferential surface before and after welding in a comparative example and an example.

Next, an embodiment of the present invention will be described in detail with reference to the drawings as appropriate.
As shown in Fig. 1, a clutch unit 1 of an embodiment equipped with a brake device of the present invention is applied to a known height adjustment mechanism for adjusting the height of a seat cushion S1 of a vehicle seat S, which is an example of a vehicle seat. The clutch unit 1 has a lever 75 attached to an operation input member 50, and the height of the seat cushion S1 can be adjusted by operating the lever 75 to rotate an output side rotating member 30 described later to drive the height adjustment mechanism. Specifically, when the lever 75 is raised from a neutral position N, the seat cushion S1 is raised by a predetermined amount, and when the lever 75 is lowered from the neutral position N, the seat cushion S1 is lowered by a predetermined amount. When the lever 75 is returned to the neutral position N from the upper or lower position, the output side rotating member 30 is not rotated.

As shown in FIG. 2, the clutch unit 1 is configured by housing each component in a housing 100. The housing 100 is configured by combining an outer ring 10 as an example of a ring, a mounting plate 85 as an example of a plate, and a cover member 60. In the following description, the left side of FIG. 2 where the cover member 60 and the operation input member 50 are arranged is referred to as the "input side," and the right side of FIG. 2 where the output side rotating member 30 is arranged is referred to as the "output side."

The clutch unit 1 is provided with a ratchet device 2 on the input side that transmits and blocks the input torque generated by the swinging motion of the operation input member 50, and a brake device 3 on the output side that transmits the input torque from the ratchet device 2 to the output gear 35 of the output side rotating member 30 and blocks the reverse input torque from the output gear 35.

The components of the ratchet device 2 and the brake device 3 are briefly described below. The ratchet device 2 includes an operation input member 50, a regulating member 71, a roller 72, a first return spring 73, a second return spring 74, a lever 75, and a retaining plate 77. The brake device 3 includes an outer ring 10, a brake shoe 20, an output side rotating member 30 as an example of a shaft, an input side rotating member 40, a roller 81 as an example of a movable piece, a spring 82, a friction member 90 as an example of a spacing member, and a washer 76. The input side rotating member 40 is an output member of the ratchet device 2 and an input member of the brake device 3, and can be said to be a part of either the ratchet device 2 or the brake device 3. The brake shoe 20 and the roller 81 of the brake device 3 are examples of components that constitute a brake mechanism that can form a brake state in which the output side rotating member 30 does not rotate relative to the outer ring 10, and a release state in which it rotates.

Next, the configurations of the brake device 3 and the ratchet device 2 will be described in detail.
First, the configuration of the braking device 3 will be described.
The outer ring 10 is made of a ring of a predetermined thickness, and has a cylindrical inner peripheral surface 11, a cylindrical outer peripheral surface 12, and a pair of side surfaces 13, 14 connecting the inner peripheral surface 11 and the outer peripheral surface 12. The pair of side surfaces 13, 14 are located radially outward of the inner peripheral surface 11 of the outer ring 10, and are planes perpendicular to the axis of the inner peripheral surface 11. In other words, the pair of side surfaces 13, 14 face in the axial direction of the inner peripheral surface 11. In the description of the brake device 3, the radial direction and circumferential direction are based on the inner peripheral surface 11 of the outer ring 10.

The mounting plate 85, which constitutes a part of the housing 100 together with the outer ring 10, is a sheet metal member for supporting the brake device 3. The mounting plate 85 has two mounting holes 85B formed therein for mounting the brake device 3 to the frame of the seat cushion S1 or the like. In addition, the mounting plate 85 has a through hole 85A formed in the center for passing the output side rotating member 30 therethrough.
The mounting plate 85 has a first surface 851 to which the side surface 14 of the outer ring 10 is fixed by laser welding, and a second surface 852 opposite to the first surface. Furthermore, a spring holding portion 85C extending toward the input side is provided on the lower part of the mounting plate 85. Since the outer ring 10 is fixed to the mounting plate 85, the clutch unit 1 can be attached to various devices.

As shown in FIG. 3, when viewed in the axial direction of the inner circumferential surface 11, the mounting plate 85 has dot-like first weld marks Wn (W1 to W6) and circular second weld marks WC at positions on the second surface 852 that overlap the outer ring 10.
The first weld marks Wn are arranged at equal angular intervals in the circumferential direction of the inner circumferential surface 11. It is preferable that the number of first weld marks Wn is four or more, and in the present embodiment, the mounting plate 85 has six first weld marks Wn, as an example. The six first weld marks Wn are located on one circumference that is coaxial with the inner circumferential surface 11.
The second weld mark WC is a circular weld mark along the circumferential direction of the inner circumferential surface 11. The second weld mark WC is located on one circumference having the same center as the inner circumferential surface 11.
FIG. 3 shows an example in which the first weld mark Wn is positioned so as to overlap the second weld mark WC, but the first weld mark Wn may be positioned outside or inside the second weld mark WC.

Returning to FIG. 2, the brake shoes 20 are components that generate a braking force between themselves and the outer ring 10, and three are arranged on the radially inner side of the outer ring 10 at equal intervals in the circumferential direction. The brake shoes 20 are configured to have a main body portion 20A that extends in the circumferential direction, and a protrusion portion 20B and a projection 20C that protrude radially outward from the outer periphery of the main body portion 20A.

The protrusions 20B are provided at both circumferential ends of the outer periphery of the main body 20A. Each protrusion 20B has a brake surface 21 at its radially outer tip that faces the inner circumferential surface 11 of the outer ring 10 and can contact the inner circumferential surface 11. This brake surface 21 has approximately the same curvature as the inner circumferential surface 11 of the outer ring 10, and is arranged so that the brake surface 21 contacts the inner circumferential surface 11 of the outer ring 10 near the outer circumferential side (the outer circumferential side based on each brake shoe 20) as shown in FIG. 4. As a result, when the brake shoe 20 is biased radially outward, the contact portion of the brake surface 21 near the outer circumferential side is pressed against the inner circumferential surface 11 of the outer ring 10.

The protrusion 20C is provided at the circumferential center of the outer periphery of the main body 20A. A support surface 26 that can abut against the inner circumferential surface 11 of the outer ring 10 is provided at the radially outer tip of the protrusion 20C. In other words, the support surface 26 is provided at the center between the pair of brake surfaces 21. This support surface 26 has approximately the same curvature as the inner circumferential surface 11 of the outer ring 10 and has a cylindrical surface shape that follows the inner circumferential surface 11 of the outer ring 10. The support surface 26 is spaced from the inner circumferential surface 11 of the outer ring 10 when no load is applied to the brake shoe 20 and the output side rotating member 30.

The brake shoe 20 has a cylindrical outer peripheral surface 22 with a smaller diameter than the brake surfaces 21 between one of the pair of brake surfaces 21 and the support surface 26, and between the other of the pair of brake surfaces 21 and the support surface 26. The brake shoe 20 also has an inner surface 23 facing radially inward. The brake shoe 20 also has end surfaces 24 at its circumferential ends that connect both ends of the inner surface 23 to the ends 21E of the two brake surfaces 21. The brake shoe 20 also has a rotational force input surface 25 facing circumferentially formed at the step between the brake surfaces 21 and the outer peripheral surface 22.

The inner surface 23 has three surfaces that face the opposing surface 36 of the output side rotating member 30, which will be described later. In detail, as shown in FIG. 5(a), the inner surface 23 has a first contact surface 23A, a first inclined surface 23B arranged on the counterclockwise side of the first contact surface 23A, and a first inclined surface 23C arranged on the clockwise side of the first contact surface 23A. The first contact surface 23A is capable of contacting the roller 81 and is a plane parallel to the direction along the straight line L1 (see FIG. 4) that connects both circumferential ends 21E of the pair of brake surfaces 21 (connection direction indicated by an arrow in FIG. 5(a)). The first inclined surfaces 23B and 23C are planes inclined with respect to the first contact surface 23A so as to approach the opposing surface 36 (lower side of the figure) as they move away from the first contact surface 23A between them.

As shown in FIG. 2, the output side rotating member 30 is configured to include a shaft-shaped action portion 31, a flange 32 formed on the output side of the action portion 31, a support shaft portion 33 that is coaxial with the action portion 31 and has a small diameter and protrudes from the action portion 31 to the input side, and an output gear 35 formed to protrude from the output side of the flange 32. The output side rotating member 30 is disposed inside the inner circumferential surface 11. The output side rotating member 30 is also disposed radially inside each brake shoe 20. The output gear 35 protrudes to the output side through a through hole 85A in the mounting plate 85.

As shown in FIG. 4, the action part 31 has an opposing surface 36 that faces the inner surface 23 of the brake shoe 20 and a curved surface part 38 on its outer periphery. Three opposing surfaces 36 are provided on the outer periphery of the action part 31 corresponding to the inner surface 23 of each brake shoe 20. A pair of rollers 81 is disposed between each inner surface 23 and each opposing surface 36. The curved surface part 38 is a part that connects each opposing surface 36 corresponding to each brake shoe 20, and a total of three curved surface parts 38 are provided, one between each pair of opposing surfaces 36 adjacent in the circumferential direction on the outer periphery of the action part 31. The curved surface part 38 is formed as a curved surface having an arc shape in cross section centered on the rotation center of the output side rotating member 30.

As shown in FIG. 5(b), the opposing surface 36 has second contact surfaces 36A, 36B arranged at both ends of the outer circumferential surface of the opposing surface 36, and a connection surface portion 36C connecting the second contact surfaces 36A, 36B at both ends. The second contact surface 36A is arranged on the counterclockwise side of the figure relative to the connection surface portion 36C, and the second contact surface 36B is arranged on the clockwise side of the figure relative to the connection surface portion 36C.

The second contact surfaces 36A and 36B can contact the roller 81 when no load is applied to the brake shoe 20, and have an inclined portion 361 inclined relative to the first contact surface 23A and a curved portion 362 arranged continuously on the outside of the inclined portion 361. The inclined portion 361 passes through the center 11C of the inner peripheral surface 11 of the outer ring 10 and is inclined so as to approach the first contact surface 23A (upper side of the figure) as it moves away from the reference plane PL perpendicular to the first contact surface 23A. In addition, the curved portion 362 has a convex shape that is convex toward the brake shoe 20 when viewed along the axial direction of the output side rotating member 30, and is a curved surface whose radius of curvature becomes smaller as it moves away from the reference plane PL. By having such second contact surfaces 36A and 36B, the opposing surface 36 includes a portion that is non-parallel to the first contact surface 23A, which is a part of the inner surface 23 of the brake shoe 20.

As shown in FIG. 5B, the connection surface portion 36C has a flat portion 36D provided in the circumferential center and an inclined portion 36E provided at both ends in the circumferential direction. The flat portion 36D is a plane perpendicular to the reference plane PL when no load is input to the brake shoe 20 and the output side rotating member 30. As a result, the flat portion 36D is arranged parallel to the first contact surface 23A when no load is input to the brake shoe 20 and the output side rotating member 30. The inclined portion 36E is inclined so as to move away from the reference plane PL, in other words, from the end of the flat portion 36D toward the circumferential inner end of the second contact surface 36A, 36B, away from the first contact surface 23A. As a result, the opposing surface 36 has a recess 36F formed by the circumferential inner end of the second contact surface 36A, 36B and the inclined portion 36E at the connection portion between each of the second contact surfaces 36A, 36B and the connection surface portion 36C. When no load is applied to the brake shoe 20 and the output side rotating member 30, the distance between the first contact surface 23A and the connection surface portion 36C (flat surface portion 36D) is smaller than the diameter of the roller 81. However, the distance between the first contact surface 23A and the connection surface portion 36C may be greater than or equal to the diameter of the roller 81.

As shown in FIG. 4, a pair of rollers 81 are arranged between the inner surface 23 of each brake shoe 20 and each opposing surface 36 of the output side rotating member 30. Here, of the pair of rollers arranged between each inner surface 23 and each opposing surface 36, the one arranged on the counterclockwise side in FIG. 4 is roller 81A, and the one arranged on the clockwise side is roller 81B. When no load is applied to the brake shoe 20 and the output side rotating member 30, the roller 81A is sandwiched between the first contact surface 23A and the second contact surface 36A and contacts them, and the roller 81B is sandwiched between the first contact surface 23A and the second contact surface 36B and contacts them. In this way, by arranging the roller 81 between the inner surface 23 and the opposing surface 36, the load is transmitted between the inner surface 23 and the opposing surface 36 in the brake device 3 via the roller 81.

The springs 82 are compression coil springs, and are provided one each between the pair of rollers 81A, 81B. The springs 82 urge the pair of rollers 81A, 81B toward the narrow side of the space formed between the inner surface 23 and the opposing surface 36, separating them from each other in the circumferential direction.

The inner surface 23 and the opposing surface 36 are configured so that when the input rotating member 40 applies a rotational torque to the brake shoe 20, the inner surface 23 pushes the opposing surface 36 via the roller 81, causing the output rotating member 30 to rotate, but even if a rotational torque is applied to the output rotating member 30, the opposing surface 36 pushes the inner surface 23 via the roller 81, causing the brake surface 21 to be pressed against the inner circumferential surface 11 of the outer ring 10, preventing the brake shoe 20 from rotating. In other words, the inclination angle and positions of the first contact surface 23A and the second contact surfaces 36A and 36B are adjusted so that they function in this way.

The input side rotating member 40 shown in FIG. 2 is a member that can rotate around the axis of the outer ring 10 and the output side rotating member 30, etc., receives the rotation output of the ratchet device 2, and abuts against the brake shoe 20 of the brake device 3 in the circumferential direction to apply a rotational torque to the brake shoe 20. The input side rotating member 40 is configured with a cylindrical pressure-receiving ring portion 41, a plurality of engagement legs 42 protruding from the pressure-receiving ring portion 41 toward the output side, a plate-shaped portion 43 extending radially inward from near the center of the axial direction of the pressure-receiving ring portion 41, a retaining portion 44 (see FIG. 7) protruding from the output side surface of the plate-shaped portion 43 toward the output side in the axial direction of the output side rotating member 30, and a through hole 45 formed in the center of the plate-shaped portion 43. The inner peripheral surface 41A of the pressure-receiving ring portion 41 is an example of a load input surface and has a circular cross section.

Three pairs of engagement legs 42 are provided at equal intervals corresponding to each brake shoe 20, and are arranged between the inner peripheral surface 11 of the outer ring 10 and the outer peripheral surface 22 of the brake shoe 20. As shown in FIG. 4, the pair of engagement legs 42 consists of an engagement leg 42A arranged between the protrusion 20C and the protrusion 20B on the counterclockwise side of FIG. 4, and an engagement leg 42B arranged between the protrusion 20C and the protrusion 20B on the clockwise side of FIG. 4. The sizes of the protrusion 20B, the protrusion 20C, and the engagement legs 42A and 42B are set so that there is play in the rotational direction (circumferential direction) between the protrusion 20B and the protrusion 20C and the engagement legs 42A and 42B. Each engagement leg 42A and 42B is formed in approximately the same shape. The play in the rotational direction (circumferential direction) of the brake shoe 20 relative to the input side rotating member 40 (engagement legs 42A and 42B) is, for example, 4°.

The retaining portions 44 are portions that prevent the rollers 81 from falling out from between the inner surface 23 and the opposing surface 36, and are arranged between the rollers 81 in the circumferential direction. Specifically, they are arranged adjacent to both sides in the circumferential direction of a pair of rollers 81A, 81B corresponding to each brake shoe 20, and three are provided in total.

The holding portion 44 is disposed away from the roller 81 when no load is applied to the input side rotating member 40 and the output side rotating member 30. More specifically, when a rotational torque within the normal operating range is applied to the output side rotating member 30, the holding portion 44 is disposed so as to be out of contact with the adjacent roller 81, which in this embodiment is roller 81B, located upstream in the rotational direction of the rotational torque.

The retaining portion 44 is arranged so that when the input side rotating member 40 is rotated in the same rotational direction as the rotational torque of the output side rotating member 30 from a state in which rotational torque is input to the output side rotating member 30 and brought into circumferential contact with the brake shoe 20, the retaining portion 44 is not in contact with the adjacent roller 81 downstream in the rotational direction, which in this embodiment is roller 81A.

The retaining portion 44 is arranged so as to contact the roller 81 adjacent to the downstream side of the retaining portion 44 in the rotational direction when the input side rotating member 40 is in circumferential contact with the brake shoe 20 to rotate the brake shoe 20. However, the retaining portion 44 may not contact the roller 81 when the input side rotating member 40 is rotating the brake shoe 20.

As shown in FIG. 7, the through hole 45 allows the action portion 31 of the output side rotating member 30 to be inserted, and has three circumferential surface portions 46 on its inner circumference along the curved surface portion 38 of the action portion 31, and three convex surface portions 47 arranged between each of the circumferential surface portions 46 and protruding radially inward from the circumferential surface portions 46. Each convex surface portion 47 has an apex portion 47A that protrudes most radially inward, a release surface 47B adjacent to the apex portion 47A on the clockwise side in FIG. 7 (counterclockwise side in FIG. 4), and a relief surface 47C adjacent to the counterclockwise side in FIG. 7 (clockwise side in FIG. 4).

The release surface 47B is disposed opposite the opposing surface 36, and has a shape that allows it to transmit rotational torque in the opposite rotational direction to the opposing surface 36 at approximately the same time when the input side rotating member 40 is rotated in the opposite rotational direction (counterclockwise direction in FIG. 4) to the brake shoe 20 in the circumferential direction from a state in which a rotational torque in the clockwise direction in FIG. 4 due to the weight of an occupant sitting in the vehicle seat S is input to the output side rotating member 30.

When no load is applied from the outside to the input side rotating member 40 and the output side rotating member 30, the flank surface 47C is formed such that the angle between the flat surface 36D (see FIG. 5) of the opposing surface 36 is larger than the angle between the flat surface 36D of the release surface 47B. The flank surface 47C is shaped so that it does not come into contact with the flat surface 36D when the input side rotating member 40 is rotated in the clockwise direction in FIG. 4 and comes into contact with the brake shoe 20 in the circumferential direction. However, the flank surface 47C may have the same angle between the flat surface 36D as the angle between the flat surface 36D of the release surface 47B, and may have the same function as the release surface 47B in the clockwise direction of the input side rotating member 40 in FIG. 4.

As shown in FIG. 2, the friction member 90 is a member that generates an auxiliary braking force for suppressing the output side rotating member 30 from suddenly starting to move the moment the braking force of the brake device 3 is released.
As shown in FIG. 8, the friction member 90 has a first ring portion 91, a second ring portion 92, a connecting portion 93 connecting the first ring portion 91 and the second ring portion 92, a plurality of protrusions 94 as an example of a pressure contact portion and an engagement portion protruding from the second ring portion 92, and a spacing retaining portion 95 protruding from the first ring portion 91.

As shown in FIG. 4, the spacing retaining portions 95 are disposed between the brake shoes 20 in the circumferential direction to retain the spacing between the brake shoes 20 in the rotational direction, and a plurality of spacing retaining portions 95 (three in this example) are provided to match the number of brake shoes 20. Each spacing retaining portion 95 is disposed in a substantially triangular space surrounded by two circumferentially adjacent brake shoes 20 and the retaining portion 44. In other words, the spacing retaining portions 95 are disposed by effectively utilizing the space between the two brake shoes 20 and the retaining portion 44, so that the brake device 3 can be prevented from becoming large.

8, the first ring portion 91 is a portion that connects a plurality of spacing retaining portions 95 and retains the spacing retaining portions 95 so as to be rotatable together. The first ring portion 91 has a fitting hole 91A having the same shape as the outline of the cross section of the action portion 31, and the first ring portion 91 does not rotate relative to the output side rotating member 30 by fitting the action portion 31 into the fitting hole 91A.
The second ring portion 92 is a portion that holds the multiple protrusions 94 so that they can rotate together, and is disposed radially outward from the first ring portion 91 .

The protrusion 94 protrudes radially outward from the outer ring 10 and toward the input side in the axial direction of the output side rotating member 30. The radially outer surface of the protrusion 94 forms a pressing surface 94A that is pressed against the inner peripheral surface 11 of the outer ring 10. The pressing surface 94A is formed to have a diameter slightly larger than the inner diameter of the inner peripheral surface 11. On the other hand, the outer peripheral surface 92A of the second ring portion 92 other than the protrusion 94 has a diameter smaller than the inner diameter of the inner peripheral surface 11 of the outer ring 10. Therefore, when the friction member 90 is assembled to the outer ring 10, only the pressing surface 94A is pressed against the inner peripheral surface 11, and the outer peripheral surface 92A is separated from the inner peripheral surface 11.

In addition, the protruding portion 94, a portion protruding in the axial direction from the second ring portion 92, engages with the brake shoe 20 in the circumferential direction. As shown in FIG. 4, the protruding portion 94 is disposed between a pair of protruding portions 20B in one brake shoe 20. More specifically, the protruding portion 94 includes a first protruding portion 94X and a second protruding portion 94Y. The first protruding portion 94X is disposed between the protrusion 20C of the brake shoe 20 and the protruding portion 20B disposed on the clockwise side of FIG. 4 with respect to the protrusion 20C. The second protruding portion 94Y is disposed between the protrusion 20C of the brake shoe 20 and the protruding portion 20B disposed on the counterclockwise side of FIG. 4 with respect to the protrusion 20C. As shown in FIG. 8, the first protruding portion 94X has a first engagement surface 94B at the end in the clockwise direction of FIG. 8, and the second protruding portion 94Y has a second engagement surface 94C at the end in the counterclockwise direction of FIG. 8. As shown in FIG. 4, when no load is applied to the input side rotating member 40, the first engagement surface 94B and the second engagement surface 94C are both spaced apart from the rotational force input surface 25 of the protruding portion 20B of the brake shoe 20.

8, the connecting portion 93 includes winding, serpentine connecting portions 93A and 93B and a plate-shaped connecting portion 93C. Three connecting portions 93A are provided in a U-shape that opens in the clockwise direction in the figure, and three connecting portions 93B are provided adjacent to connecting portion 93A in the clockwise direction and have a U-shape that opens in the counterclockwise direction. The plate-shaped connecting portion 93C is disposed between connecting portion 93A adjacent to connecting portion 93B on the clockwise side.
The connecting portions 93A and 93B have a thin shape that is flexible and deformable, while the connecting portion 93C has a wide plate shape that is less prone to flexible deformation than the connecting portions 93A and 93B.
In this way, the first ring portion 91 and the second ring portion 92 are not formed as a single, integral plate, but are connected by multiple connecting portions 93, which allows the connecting portions 93 to bend somewhat when a rotational torque is input to one of the first ring portion 91 and the second ring portion 92. This makes it easier for the friction member 90 to simultaneously perform the function of generating an auxiliary braking force and the function of balancing the circumferential positions of the multiple brake shoes 20.

The material constituting the friction member 90 is not particularly limited, but the friction member 90 is made of, for example, resin.

As shown in FIG. 2, the friction member 90 is disposed on the output side of the brake shoe 20. The friction member 90 is press-fitted into the inside of the outer ring 10, and each protrusion 94 is disposed between the protrusion 20B and the projection 20C of the brake shoe 20. Each protrusion 94 is formed in approximately the same range as the engagement legs 42A, 42B in the rotational direction. Therefore, the play in the rotational direction (circumferential direction) of the brake shoe 20 relative to each protrusion 94 is, for example, 4°.

As shown in FIG. 6(a), the washer 76 has a hole 76A with a diameter slightly smaller than the outer diameter of the support shaft portion 33 of the output side rotating member 30, and this hole 76A is press-fitted into the support shaft portion 33. The outer diameter of the washer 76 is larger than the support hole 64 of the cover member 60 described below, and the washer 76 prevents the output side rotating member 30 from slipping out to the output side.

Next, the configuration of the ratchet device 2 will be described.
2, the operation input member 50 is engaged with a lever 75 and can be swung together with the lever 75 within a predetermined angle range from a neutral position. The operation input member 50 is a member that moves integrally with the input side rotating member 40 via the rollers 72, thereby transmitting rotational torque from the lever 75 to the input side rotating member 40 via the rollers 72. For this reason, the operation input member 50 includes a cam plate portion 51 and two lever engagement portions 52 that extend from the cam plate portion 51 to the input side and serve as attachment portions for the levers 75.

As shown in FIG. 10(a), the cam plate portion 51 has three arc-shaped small diameter portions 53 on its outer circumferential surface, and an action surface 55 that extends continuously from the small diameter portions 53 in the circumferential direction and has a gradually larger diameter than the small diameter portions 53. The cam plate portion 51 has three protruding portions 54 that protrude from the action surface 55 so as to approach the inner circumferential surface 41A of the pressure-receiving ring portion 41, which is the load input surface. The small diameter portions 53 and the protruding portions 54 are alternately arranged in the circumferential direction, and the action surfaces 55 are arranged in a total of six locations between each protruding portion 54 and each small diameter portion 53 in the circumferential direction. In the description of the ratchet device 2, the radial and circumferential directions are used as the load input surface, here, the inner circumferential surface 41A is used as the reference.

The action surface 55 faces the inner circumferential surface 41A in the radial direction. In addition, the action surface 55 is non-parallel to the inner circumferential surface 41A, and is formed such that the distance between the action surface 55 and the inner circumferential surface 41A becomes narrower as the action surface 55 approaches the protruding portion 54.
Further, a hole 56 through which the output side rotation member 30 passes is formed in the center of the cam plate portion 51 .

A roller 72 is disposed between each of the action surfaces 55 and the inner peripheral surface 41A of the pressure-receiving ring portion 41. As will be understood from the operation explanation described below, the roller 72 transmits and blocks the input torque by engaging and disengaging with the operation input member 50 and the input side rotating member 40. A total of six rollers 72 are disposed corresponding to each action surface 55.

10B, the protrusion 54 has a step surface 54A extending from the action surface 55 so as to approach the inner circumferential surface 41A, a top surface 54B extending from an end of the step surface 54A close to the inner circumferential surface 41A in the rotation direction of the input side rotating member 40, and a corner portion 54C connecting the step surface 54A and the top surface 54B. The step surface 54A is inclined with respect to the action surface 55 so as to move away from the roller 72 as it moves radially outward. In this embodiment, the protrusion amount of the protrusion 54 is relatively small, and the protrusion 54 has a shape that contacts the roller 72 at the corner portion 54C. Specifically, the protrusion 54 has a shape that contacts the movable piece at a position closer to the action surface 55 than the center 72A of the roller 72 in the radial direction. The corner portion 54C includes a shape that has a roundness of a size required for manufacturing.

Returning to FIG. 2, the regulating member 71 will now be described. The regulating member 71 is a member that regulates the position of the rollers 72, and is configured with a side wall portion 71A arranged on the output side, which is one side of the rotation axis direction of the operation input member 50, relative to the multiple rollers 72, and three regulating portions 71B that extend from the outer periphery of the side wall portion 71A toward the input side. The regulating portions 71B are longer than the axial length of the rollers 72, and their tips are press-fitted into the fitting holes 66 of the cover member 60. The regulating member 71 also has a hole 71C in the center through which the output side rotating member 30 passes.

As shown in FIG. 10(a), the regulating portion 71B is disposed at the same rotational position radially outside the protruding portion 54 when the lever 75 is not being operated and regulates the circumferential movement of the roller 72 between the action surface 55 and the pressure-receiving ring portion 41. Between the two rollers 72 disposed between the adjacent regulating portions 71B, a first return spring 73 made of a compression coil spring is disposed with an initial load applied. Therefore, in the non-operating state of FIG. 10(a), each roller 72 is in contact with the regulating portion 71B. Here, the regulating portion 71B is disposed so as to include the position where the center of the roller 72 is located in the radial direction of the outer ring 10, and is in contact with the most protruding part of the roller 72 in the circumferential direction. This allows the regulating portion 71B to stably support the roller 72. In FIG. 10(a), the roller 72 is shown in contact with the restricting portion 71B, but the roller 72 may be slightly separated from the restricting portion 71B by being sandwiched between the action surface 55 and the inner circumferential surface 41A.

As shown in FIG. 2, the lever engagement portion 52 has an arc-shaped cross section and protrudes from the cam plate portion 51 in the axial direction of the output side rotating member 30. Each lever engagement portion 52 has a screw hole 52A on its axial end face. In addition, each lever engagement portion 52 has a fan shape when viewed from the axial direction and a side surface 52B extending in the radial direction (see FIG. 10(a)).

The cover member 60 includes a disk-shaped side wall portion 61 and an outer circumferential portion 62 extending from the outer circumferential edge of the side wall portion 61 toward the output side in the axial direction of the output side rotation member 30 .
The side wall portion 61 has a direction intersecting the axial direction of the output side rotation member 30, and in this embodiment, has a direction perpendicular to the axial direction.
6(a), the outer peripheral portion 62 has a small diameter portion 62A extending from the side wall portion 61, a flange portion 62B extending radially from the output side end of the small diameter portion 62A, and a large diameter portion 62C extending to the output side from the outer circumferential edge of the flange portion 62B. The large diameter portion 62C is fitted onto the outside of the outer circumferential surface 12 of the outer ring 10 and fixed to the outer ring 10 by laser welding.
The outer circumferential portion 62 is disposed between the first return spring 73 and the second return spring 74 to suppress interference between the first return spring 73 and the second return spring 74 .

As shown in FIG. 2 , the side wall portion 61 is formed with a circular support hole 64 at its center, two arc holes 65 extending in an arc shape around the support hole 64, three fitting holes 66 positioned radially outward from the arc holes 65 and arranged at equal intervals in the circumferential direction, and a protrusion 67 protruding toward the inside of the housing 100.
The support hole 64 is a portion that fits onto the support shaft portion 33 of the output side rotation member 30 and supports the output side rotation member 30 .
The arc hole 65 is provided corresponding to the lever engagement portion 52 of the operation input member 50, and is formed in an arc shape with a wider angular range than the lever engagement portion 52. This allows the lever engagement portion 52 to be received in the arc hole 65, and allows the lever engagement portion 52 to move within the arc hole 65 within a predetermined angular range.
6B, the convex portion 67 includes a first convex portion 67A that protrudes toward the operation input member 50 and a second convex portion 67B that protrudes toward the pressure-receiving ring portion 41 of the input-side rotation member 40. The convex portion 67 is slidable with these components inside the housing 100, and suppresses play of the components inside the housing 100 in the axial direction.

The fitting holes 66 are through holes provided in three locations corresponding to the three restricting portions 71B of the restricting member 71 (see also FIG. 2), and are fitted with the cover member 60 so that the restricting member 71 does not rotate relative to the cover member 60. The restricting member 71 and the cover member 60 are fitted with each other at multiple locations, so that the rotation of the restricting member 71 can be firmly restricted.

When assembling the cover member 60 with the outer ring 10 during manufacture of the clutch unit 1, first, the large diameter portion 62C of the outer peripheral portion 62 is fitted onto the outside of the outer peripheral surface 12 of the outer ring 10. Then, the side wall portion 61 is pressed toward the output side in the axial direction of the output side rotating member 30 with a predetermined load to bring the protrusion 67 into contact with a component inside the housing (the input side rotating member 40), while the cover member 60 is fixed to the outer ring 10 by laser welding. Specifically, a laser is irradiated onto the outer peripheral surface of the large diameter portion 62C of the cover member 60 to form a weld WS for fixing.
The first protrusion 67A prevents the operation input member 50 from moving axially between the side wall portion 71A of the restricting member 71 and the side wall portion 61 of the cover member 60. For this reason, when the restricting portion 71B is press-fitted into the fitting hole 66, the restricting portion 71B is press-fitted with a load that brings the first protrusion 67A and the operation input member 50 into light contact with each other.

Returning to FIG. 2, the second return spring 74 is a torsion spring having a coil portion 74A, a first arm 74B extending radially outward from one end of the coil portion 74A, and a second arm 74C extending radially outward from the other end of the coil portion 74A. The coil portion 74A is disposed radially outward from the outer periphery 62 of the cover member 60.

2, a spring engagement portion 75B extending from the lower end of the main body portion 75A toward the output side, and a cover portion 75C extending from the upper end of the main body portion 75A toward the output side. The main body portion 75A is located on the input side with respect to the coil portion 74A of the second return spring 74. The first arm 74B and the second arm 74C of the second return spring 74 engage with the spring engagement portion 75B.
The main body 75A is formed with a circular through hole 75D through which the support shaft 33 of the output side rotating member 30 passes and two engagement holes 75E with which the two lever engagement parts 52 of the operation input member 50 engage, in a connected state. As shown in FIG. 10(a), the engagement hole 75E has an edge part 75F extending in the radial direction. The lever engagement part 52 is press-fitted into the engagement hole 75E so that the edge part 75F of the engagement hole 75E pinches the lever engagement part 52 in the rotation direction of the operation input member 50. In other words, this press-fitting causes the edge part 75F and the side surface 52B of the lever engagement part 52 to be in constant pressure contact, so that the lever 75 does not have any play in the rotation direction relative to the operation input member 50. This improves the operability of the lever 75.

As shown in FIG. 9, the spring engagement portion 75B has the same size in the circumferential direction as the spring retaining portion 85C of the mounting plate 85. The spring engagement portion 75B is disposed radially outward of the spring retaining portion 85C at a position corresponding to the spring retaining portion 85C in the circumferential direction. The spring engagement portion 75B and the cover portion 75C are also positioned radially outward of the coil portion 74A of the second return spring 74, preventing the coil portion 74A from coming off.

The first arm 74B and the second arm 74C of the second return spring 74 are rotationally engaged with the spring retaining portion 85C of the mounting plate 85 and the spring engaging portion 75B of the lever 75. When the lever 75 is not being operated, the first arm 74B and the second arm 74C are biased in a direction approaching each other, sandwiching the spring retaining portion 85C and the spring engaging portion 75B. In other words, the lever 75 is constantly biased by the second return spring 74 toward the neutral position shown in FIG. 9.

The retaining plate 77 has two holes 77A corresponding to the screw holes 52A, and a center hole 77B corresponding to the through hole 75D of the lever 75. The center hole 77B prevents the washer 76 (see FIG. 2) from interfering with the retaining plate 77.
The retaining plate 77 is fixed to the operation input member 50 by two bolts 78 passing through the holes 77A and fastening to the screw holes 52A. This prevents the lever 75 from coming off the operation input member 50.

Next, the operation of the clutch unit 1 configured as above will be described.
First, the operation of the ratchet device 2 will be described.
In the neutral position shown in FIG. 10A, the roller 72 is located between the inner peripheral surface 41A of the input side rotation member 40 and the working surface 55 of the operation input member 50, but there is a small gap between them and the roller 72 is not sandwiched between them. The roller 72 is biased toward the regulating portion 71B by the first return spring 73 made of a compression coil spring. As a result, the first return spring 73 biases the attitude of the operation input member 50 to the neutral position. In addition, the second return spring 74 pinches the spring engaging portion 75B and the spring holding portion 85C between the first arm 74B and the second arm 74C. Due to this pinching force, the position of the spring engaging portion 75B in the rotation direction is aligned with the spring holding portion 85C. In other words, the second return spring 74 biases the attitude of the lever 75 and the operation input member 50 to the neutral position.

When the load applied to the input side rotation member 40 is less than a predetermined value, when the lever 75 is lowered from the neutral position to slightly swing the operation input member 50 in the clockwise direction, the action surface 55 rotates clockwise and comes into contact with the roller 72, and the roller 72 is sandwiched between the inner circumferential surface 41A and the action surface 55. This allows the operation input member 50 and the input side rotation member 40 to rotate together in response to the swing operation of the operation input member 50.
11 , when the operation input member 50 is rotated clockwise, the input side rotation member 40 and the operation input member 50 rotate clockwise while remaining integrated with each other. In other words, the input torque that rotates the operation input member 50 is transmitted to the input side rotation member 40.

At this time, the spring engagement portion 75B of the lever 75 moves the second arm 74C in the clockwise direction against the biasing force of the second return spring 74. In other words, the second arm 74C biases the spring engagement portion 75B in the counterclockwise direction.

When the lever 75 is swung counterclockwise from the state shown in FIG. 11 to return it from the lower position to the neutral position, the action surface 55 moves counterclockwise away from the roller 72, and as shown in FIG. 12, the operation input member 50 rotates toward the neutral position while the input side rotating member 40 remains stationary. In other words, the input torque when returning the operation input member 50 is not transmitted to the input side rotating member 40 and is cut off. The biasing force of the first return spring 73 and the second return spring 74 assists in operating the operation input member 50 toward the neutral position and maintains it in the neutral position.

The operation of raising the lever 75 from the neutral position upward and returning it from the upward position to the neutral position is the same as in the case of the downward swing described above, so a description is omitted.

Next, the operation of the brake device 3 will be described.
As shown in Figure 13, when the weight of an occupant sitting in the vehicle seat S applies a rotational torque in the clockwise direction in the figure, that is, a rotational torque within the normal usage range, to the output side rotating member 30, the output side rotating member 30 rotates slightly clockwise and the gap between the second contact surface 36A (the counterclockwise one of the pair of second contact surfaces 36A, 36B of one opposing surface 36) and the first contact surface 23A narrows, thereby increasing the pressure between the roller 81A (the counterclockwise one of the pair of rollers 81 corresponding to one brake shoe 20) and the second contact surface 36A and the first contact surface 23A. When the roller 81A is in contact with the first inclined surface 23B in a state where no load is input to the output side rotating member 30, the roller 81A rolls between the opposing surface 36 and the inner surface 23, and when the roller 81A moves to a position where it contacts the first contact surface 23A, the pressure between the second contact surface 36A and the first contact surface 23A increases sufficiently to stop the roller 81A against the opposing surface 36 and the inner surface 23. On the other hand, as the output side rotating member 30 rotates clockwise, the interval between the second contact surface 36B (the clockwise one of the pair of second contact surfaces 36A, 36B of one opposing surface 36) and the first contact surface 23A becomes wider, so that the roller 81B (the clockwise one of the pair of rollers 81 corresponding to one brake shoe 20) can roll without being strongly pinched between the second contact surface 36B and the first contact surface 23A.

At this time, the second contact surface 36A presses the roller 81A with force F1, and the roller 81A presses the first contact surface 23A with force F2. As a result, the pair of brake surfaces 21 of the brake shoe 20 are pressed against the inner peripheral surface 11 of the outer ring 10 with force F3. As a result, frictional force is generated between the brake surfaces 21 and the inner peripheral surface 11, so that the output side rotating member 30 does not rotate. In other words, a braking force that prevents the vehicle seat S from lowering is generated. In this state where a rotational torque within the normal use range is applied to the output side rotating member 30, the support surface 26 is separated from the inner peripheral surface 11 of the outer ring 10.

At this time, roller 81B is slightly separated from the adjacent retaining portion 44 in the rotational direction of output side rotating member 30, i.e., the clockwise direction. Therefore, not only is roller 81A sandwiched between opposing surface 36 and inner surface 23, but the biasing force of spring 82 also allows roller 81B to maintain a state sandwiched between opposing surface 36 and inner surface 23. As a result, regardless of the direction in which brake shoe 20 is subsequently rotated, the frictional force between brake shoe 20 and outer ring 10 can be maintained, thereby preventing unexpected release of braking force.

When the lever 75 is operated to rotate the input side rotating member 40 counterclockwise to raise the height of the vehicle seat S from the brake state shown in FIG. 13, as shown in FIG. 14, the counterclockwise end of the engagement leg 42A of the input side rotating member 40 abuts against the rotational force input surface 25 of the brake shoe 20 in the circumferential direction. At this point, the release surface 47B of the input side rotating member 40 contacts the flat surface portion 36D of the opposing surface 36 at approximately the same time, making it possible to transmit the rotational torque in the counterclockwise direction to the output side rotating member 30. As a result, even if the brake surface 21 of the brake shoe 20 is strongly pressed against the inner peripheral surface 11 of the outer ring 10, the braking force can be released and the feeling of sticking when the input side rotating member 40 is rotated to start raising the vehicle seat S can be suppressed.

When the input side rotating member 40 is further rotated counterclockwise, the engaging leg 42A presses the rotational force input surface 25 with force F11, causing the brake shoe 20 to rotate in the counterclockwise direction, the first contact surface 23A presses the roller 81A with force F12, and the roller 81A presses the second contact surface 36A with force F13. This force F13 causes the output side rotating member 30 to rotate counterclockwise in the figure. At this time, the support surface 26 is still separated from the inner peripheral surface 11 of the outer ring 10.

When the lever 75 is operated to rotate the input side rotating member 40 clockwise in order to lower the height of the vehicle seat S from the brake state shown in FIG. 13, as shown in FIG. 15, the clockwise end of the engagement leg 42B of the input side rotating member 40 abuts against the rotational force input surface 25 of the brake shoe 20 in the circumferential direction. At this time, the retaining portion 44 is not in contact with the adjacent roller 81A on the downstream side in the rotational direction (clockwise direction side). Then, when the input side rotating member 40 is further rotated clockwise, the engagement leg 42B presses against the rotational force input surface 25 with a force F21, and the brake shoe 20 begins to rotate in the clockwise direction.

When the brake shoe 20 rotates clockwise from the state shown in Fig. 15, the brake shoe 20 and the output side rotating member 30 move in a manner relatively opposite to that when the output side rotating member 30 is rotated clockwise in Fig. 13. That is, as shown in Fig. 16, the brake shoe 20 rotates slightly clockwise, and the gap between the first contact surface 23A and the second contact surface 36B (the clockwise one of the pair of second contact surfaces 36A, 36B of one opposing surface 36) narrows, and the pressure between the roller 81B (the clockwise one of the pair of rollers 81 corresponding to one brake shoe 20) and the first contact surface 23A and second contact surface 36B increases. Incidentally, even when the roller 81B is in contact with the first inclined surface 23C, the roller 81B rolls between the opposing surface 36 and the inner surface 23, and when it moves to a position where it contacts the first contact surface 23A, the pressure between the second contact surface 36B and the first contact surface 23A increases sufficiently to stop the roller 81B against the opposing surface 36 and the inner surface 23. On the other hand, as the brake shoe 20 rotates clockwise, the distance between the first contact surface 23A and the second contact surface 36A (the counterclockwise one of the pair of second contact surfaces 36A, 36B of one opposing surface 36) increases, so that the roller 81A (the counterclockwise one of the pair of rollers 81 corresponding to one brake shoe 20) can roll while the pressure between them gradually decreases. In the state shown in FIG. 16, the holding portion 44 is in contact with the adjacent roller 81A downstream in the rotation direction and presses the roller 81A in the clockwise direction.

In addition, in the process of the brake shoe 20 rotating from the state of FIG. 15 to the state of FIG. 16, the gap between the protruding portion 20B of the brake shoe 20 and the second protruding portion 94Y of the friction member 90 becomes narrow, and the protruding portion 20B engages with the second protruding portion 94Y and pushes it in the clockwise direction. As a result, the friction member 90 rotates clockwise as if being dragged by the brake shoe 20. At this time, the friction member 90 is pressed against the inner peripheral surface 11 of the outer ring 10 at the protruding portion 94, so that resistance (auxiliary braking force) is applied to the rotation of the brake shoe 20. Therefore, even if the force clamping the roller 81A between the first contact surface 23A and the second contact surface 36A weakens before the roller 81B is clamped between the first contact surface 23A and the second contact surface 36B with sufficient force, the brake shoe 20 is prevented from suddenly rotating clockwise due to the weight of the occupant.

In addition, in the state shown in FIG. 15, the holding portion 44 is not in contact with the roller 81A, so that before the roller 81B is pinched between the first contact surface 23A and the second contact surface 36B with sufficient force, the roller 81A, which was generating a braking force, is not pressed by the holding portion 44, thereby preventing the braking force from weakening unexpectedly.

On the other hand, as shown in FIG. 16, after the roller 81B is clamped between the first contact surface 23A and the second contact surface 36B with sufficient force, the retaining portion 44 comes into contact with the roller 81A. Therefore, even if the roller 81A becomes stuck between the inner surface 23 and the opposing surface 36 due to some reason, the roller 81A can be removed from between the inner surface 23 and the opposing surface 36 to release the braking force and achieve stable operation.

As shown in FIG. 16, the engagement leg 42B presses the rotational force input surface 25 with a force F21, the first contact surface 23A presses the roller 81B with a force F22, and the roller 81B presses the second contact surface 36B with a force F23. This force F23 causes the output side rotating member 30 to rotate clockwise in the figure. At this time, the support surface 26 is also spaced from the inner peripheral surface 11 of the outer ring 10.

On the other hand, when an excessive clockwise rotational torque larger than the normal use range is input to the output side rotating member 30, as shown in FIG. 17, the output side rotating member 30 rotates more clockwise than when a rotational torque within the normal use range is applied, and the gap between the second contact surface 36A and the first contact surface 23A becomes narrower, so that the pressure between the roller 81A and the second contact surface 36A and the first contact surface 23A increases. At this time, the second contact surface 36A presses the roller 81A with a large force F31, and the roller 81A presses the first contact surface 23A with a large force F32. As a result, the brake shoe 20 is deformed so that the main body 20A bends radially outward, and the support surface 26 abuts against the inner peripheral surface 11 of the outer ring 10. As a result, the support surface 26 of the brake shoe 20 is supported by the outer ring 10, and further deformation is suppressed, so that the load on the brake shoe 20 can be reduced.

In addition, if excessive clockwise rotational torque is input and the output side rotating member 30 rotates significantly in the clockwise direction, the gap between the second contact surface 36B and the first contact surface 23A may widen, causing the roller 81B to move between them. In such a case, the roller 81B abuts against the adjacent retaining portion 44 on the downstream side in the rotation direction, in this case the clockwise direction. As a result, the retaining portion 44 supports the roller 81B, preventing the roller 81B from falling out from between the inner surface 23 and the opposing surface 36.

In the above, a case has been described in which the input side rotating member 40 is rotated in a clockwise or counterclockwise direction after a clockwise rotational torque is input to the output side rotating member 30 to generate a braking force. When the clutch unit 1 is applied to a vehicle seat S, only a clockwise rotational torque is input to the output side rotating member 30, so it only operates as described above. However, if a counterclockwise rotational torque is input to the output side rotating member 30 to generate a braking force, and then the input side rotating member 40 is rotated in a clockwise or counterclockwise direction, the brake shoe 20 and the output side rotating member 30 are configured to be approximately mirror symmetrical (line symmetrical in FIG. 4), so that approximately the same operation is realized, except for the direction of rotation.

Next, a manufacturing method for fixing the outer ring 10 and the mounting plate 85 and a difference in the roundness of the inner peripheral surface 11 of the outer ring 10 due to differences in the manufacturing method will be described.
18 and 19, a welding jig 200 and a laser irradiator 250 are used to fix the outer ring 10 and the mounting plate 85. The welding jig 200 includes a fixed stage 210 and a bolt 220.

The fixed stage 210 has a clamp table 211 and a positioning jig 210A. The clamp table 211 is a portion that protrudes upward from the main body of the fixed stage 210 and supports the mounting plate 85. Three clamp tables 211 are provided corresponding to the mounting holes 85B of the mounting plate 85.
The positioning jig 210A has a mounting plate positioning portion 212, an inner circumference chuck portion 215, and a ring pedestal portion 216. The positioning jig 210A is fixed to the main body of the fixed stage 210 by bolts 219.
The mounting plate positioning portion 212 is a portion that fits into the through hole 85 A of the mounting plate 85 to determine the position of the mounting plate 85 .
The inner circumference chuck portion 215 is a substantially equilateral triangular member that fits into the inner circumference surface 11 on the inside of the outer ring 10, and positions the inner circumference surface 11 of the outer ring 10 at three points from the inside.
The ring seat portion 216 is a portion that supports the outer ring 10 from below.

The laser irradiator 250 is a device that irradiates a laser for laser welding, and is controlled so that the output and direction of the laser can be changed.

When laser welding is performed using the welding jig 200, as shown in FIG. 18, the outer ring 10 is fitted into the inner circumference chuck portion 215 and placed on the ring base portion 216. Then, as shown in FIGS. 19(a) and (b), the through hole 85A of the mounting plate 85 is fitted into the mounting plate positioning portion 212 to place the mounting plate 85 on the outer ring 10, and the mounting plate 85 is fixed to the outer ring 10 by the bolt 220. That is, the outer ring 10 is positioned on the mounting plate 85 with the side surface 14 of the outer ring 10 in contact with the first surface 851 (positioning process).

Then, the laser irradiator 250 irradiates the second surface 852 with a laser beam in a dot pattern at a position that overlaps with the outer ring 10 when viewed from the axial direction, thereby welding the outer ring 10 to the mounting plate 85 temporarily (first welding step). The dot pattern welding positions (see the first weld marks Wn (W1 to W6) in FIG. 3) are four or more positions spaced at equal angular intervals around the inner circumferential surface 11.

Next, the laser irradiator 250 continuously irradiates the second surface 852 with a laser along the circumferential direction at a position that overlaps with the outer ring 10 when viewed from the axial direction, thereby laser welding the second surface 852 in a circular shape. This completes the fixation of the outer ring 10 to the mounting plate 85 (second welding process).

When the outer ring 10 is fixed to the mounting plate 85 in this way, heat accumulates in the parts of the outer ring 10 and mounting plate 85 that are irradiated with the laser, causing parts of the components to expand and slightly distorting the outer ring 10 and mounting plate 85. This causes the circularity of the inner surface 11 of the outer ring 10 to decrease compared to before welding.

Figure 20 shows the results of the applicant's investigation into the change in the roundness of the inner circumferential surface 11 before and after fixing the outer ring 10 to the mounting plate 85 by laser welding using multiple methods. For each method, the number of experiments was 3 (N=3).

When welding was performed only in the second welding process without performing the first welding process, as in Comparative Example 1, the change (deterioration) in circularity before and after welding was D1. This change D1 was used as the reference value.

In Comparative Example 2, the parts are temporarily fixed by spot-like laser welding, and then continuously welded in the second welding step, but the temporary fixing is performed at only three welding positions. The temporary fixing welding positions are positions corresponding to the middle of the chuck positions of the inner chuck portion 215 shown by the dashed line in the circumferential direction of the inner circumferential surface 11. In the figure, the numbers attached to the welding positions indicate the order in which the welding was performed.
In this case, the change in circularity before and after welding was D2. D2 was approximately the same value as D1, and no improvement was observed in the shape accuracy of the inner circumferential surface 11. It is considered that temporary fixing at only three points was not able to suppress the force that tends to deform the outer ring 10 and the mounting plate 85 in the second welding process.

In Example 1, temporary fixing was performed at six welding positions in the first welding process. The six welding positions correspond to the chuck position by the inner chuck portion 215 and the intermediate position between the chuck positions in the circumferential direction of the inner circumferential surface 11. Welding was performed in order counterclockwise starting from the top welding position in the figure. In Examples 1 and 2, the first welding process and the second welding process were performed without any gap between them, and each dot-like laser welding in the first welding process was also performed quickly within the range that the device could perform, without any gap between them.
In this case, the change in circularity before and after welding was D3. The improvement rate of the change was D3/D1-1=-50%. Thus, the shape accuracy of the inner circumferential surface 11 was improved.

In Example 2, temporary fixing was performed at six welding positions in the first welding process. The six welding positions were the same as those in Example 1. The temporary fixing was performed by welding at a plurality of welding positions arranged in the circumferential direction, and the welding was performed in sequence in the circumferential direction while skipping at least one welding position adjacent in the circumferential direction. Specifically, the welding positions were welded in sequence in a counterclockwise direction starting from the top welding position in the figure (see welding positions 1, 2, and 3). After this, the welding positions were welded in sequence in a counterclockwise direction starting from welding position 4, which is 180° opposite to welding position 3 in the circumferential direction (see welding positions 4, 5, and 6).
In this case, the change in circularity before and after welding was D4. The improvement rate of the change was D4/D1-1=-80%. A large improvement in the shape accuracy of the inner circumferential surface 11 was observed.

In welding tests, sufficient shape precision was achieved by temporary fixing at six or more points, but it is believed that improvements in the shape precision of the inner surface 11 can also be expected when using four or five points, which is more than three points.

According to the brake device 3 applied to the clutch unit 1 of this embodiment described above, the outer ring 10 and the mounting plate 85 are fixed together without heat accumulation by the four or more dot-like first weld marks Wn, and the outer ring 10 and the mounting plate 85 are firmly fixed together by the circular second weld marks WC. As a result, distortion of the inner peripheral surface 11 of the outer ring 10 is small, and the outer ring 10 is firmly fixed to the mounting plate 85.

In addition, according to the manufacturing method of this embodiment, in the first welding step, a laser is irradiated to four or more positions spaced at equal angular intervals around the circumferential direction of the inner circumferential surface 11 to perform spot laser welding, so that the outer ring 10 and the mounting plate 85 are temporarily fixed in place without heat accumulating. After this temporary fixing, the outer ring 10 and the mounting plate 85 are laser welded in a circular shape in the second welding step, so that the outer ring 10 can be firmly fixed to the mounting plate 85 with minimal distortion of the inner circumferential surface 11 of the outer ring 10.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment and can be modified appropriately.
For example, in the above embodiment, the shape accuracy of the inner peripheral surface 11 of the outer ring 10 is improved when the outer ring 10 and the mounting plate 85 of the brake device 3 are welded together. However, the present invention can also be applied to cases where a ring other than the outer ring or a plate other than the mounting plate is laser welded in a brake device having such a ring and plate. The present invention can also be applied to fixing by laser welding a ring or a plate in a device other than a brake device.

In addition, the mechanism that generates the braking force in the brake device is not limited to the embodiment described above.

In addition, in the above embodiment, when a rotational torque is applied to the output side rotating member 30, the brake shoe 20 is configured not to rotate regardless of whether the rotation direction is clockwise or counterclockwise. However, the brake shoe 20 may be configured not to rotate in one direction of rotation and to rotate in the other direction.

In addition, in the above embodiment, when no load is applied to the output side rotating member 30 or when a rotational torque within the normal range is applied to the output side rotating member 30 (see Figures 13 to 16), the support surface 26 is separated from the inner peripheral surface 11 of the outer ring 10, but this is not limited to the above. For example, as long as this does not interfere with the operation of the brake shoe when it rotates, the support surface may be in contact with the inner peripheral surface when a rotational torque within the normal range is applied to the output side rotating member. Furthermore, the support surface does not have to be shaped along the inner peripheral surface of the outer ring.

In the above embodiment, a roller 81 is used as an example of the movable piece, but the movable piece may be a sphere, a polygonal prism, or a cylinder with an elliptical cross section.

In the above embodiment, three brake shoes 20 were provided, but the number of brake shoes may be two or four or more.

In the above embodiment, the brake shoe 20 has a support surface 26 between a pair of brake surfaces 21, but the brake shoe may be configured without a support surface or a protrusion on which the support surface is provided.

In the above embodiment, the pressure-receiving ring portion 41 of the input side rotating member 40 is disposed radially outside the operation input member 50, but this may be reversed so that the operation input member 50 has an inner peripheral surface and the input side rotating member 40 has an outer peripheral surface as a load input surface, and a movable piece such as a roller is disposed between these inner and outer peripheral surfaces.

The brake device 3, ratchet device 2 and clutch unit 1 can be used not only in the height adjustment mechanism of the vehicle seat S, but also in any other device.

Furthermore, the elements described in the above embodiments and variations may be implemented in any combination.

3 Brake device 10 Outer ring 11 Inner peripheral surface 14 Side surface 20 Brake shoe 30 Output side rotating member 85 Mounting plate 851 First surface 852 Second surface Wn First weld mark WC Second weld mark

Claims (1)

A ring having a cylindrical inner circumferential surface and a side surface facing an axial direction of the inner circumferential surface;
1. A method for manufacturing an apparatus comprising: a plate having a first surface and a second surface opposite to the first surface, the side surface of the ring being fixed to the first surface of the plate by laser welding, the method comprising:
a positioning step of positioning the ring on the plate with the side surface of the ring in contact with the first surface;
a first welding step of irradiating a laser to six positions on the second surface that are spaced apart at equal angular intervals in a circumferential direction of the inner circumferential surface at positions that overlap with the ring when viewed in the axial direction, thereby laser welding the ring to the plate in a dot pattern;
a second welding step of continuously irradiating a laser beam along the circumferential direction to a position on the second surface that overlaps with the ring as viewed from the axial direction, thereby laser welding the second surface in a circular shape, and finally fixing the ring to the plate;
A method for manufacturing a device, characterized in that in the first welding process, a laser is irradiated in a dot pattern at three positions that are equally spaced circumferentially on the inner surface to perform laser welding, and then a laser is irradiated in a dot pattern at three positions between the three dot-like welded positions to perform laser welding.

Images