WO2021065726A1

WO2021065726A1 - Brake device

Info

Publication number: WO2021065726A1
Application number: PCT/JP2020/036307
Authority: WO
Inventors: 将太郎國立; 貴之清水
Original assignee: 株式会社アドヴィックス
Priority date: 2019-09-30
Filing date: 2020-09-25
Publication date: 2021-04-08
Also published as: JP7347086B2; JP2021054314A

Abstract

A brake device according to the present disclosure is provided with an elastic member which is configured in, for example, an annular shape and can be sandwiched between a flange and a linear motion member according to the movement of the linear motion member in a second direction, the elastic member having: an inner circumferential part that is accommodated in a bottomed recess section of a rotary member, extends in the circumferential direction of a male screw, and faces the outer circumferential surface of the male screw; and an outer circumferential part that extends in the circumferential direction, faces the inner circumferential surface of a circumferential wall, and is spaced apart from the inner circumferential surface in a maximal axial offset state in the radial direction with respect to the male screw.

Description

Brake device

This disclosure relates to a braking device.

Conventionally, a rotating member that rotates in conjunction with the output shaft of the motor and a linear moving member that moves linearly in response to the rotation of the rotating member are provided, and the brake shoe is moved by pulling a cable by the linear moving member. A braking device for braking is known (for example, Patent Document 1).

According to Japanese Patent Application Laid-Open No. 2019-006223, when the disc spring is compressed between the linear motion member and the rotary member, the disc spring is compressed from the braking position of the linear motion member to the non-braking position, that is, toward the rotary member, during the return operation. A load is applied to the motor. This prevents, for example, mutual interference between the linear motion member and the rotating member during the return operation. Then, it is possible to suppress the difficulty of returning due to the screw mechanisms of the linear motion member and the rotating member being fastened too strongly.

In the above-mentioned conventional technique, the disc spring may be displaced in the radial direction, and the disc spring may come into contact with the inner peripheral surface of the recess for accommodating the disc spring, that is, the inner peripheral surface of the peripheral wall of the rotating member. As a result, the posture of the disc spring may not be stable, and it may be difficult to obtain the desired compression reaction force.

One of the problems of the present disclosure is, for example, to obtain a brake device having a new configuration with less inconvenience, which can prevent the screw mechanism from being tightened too strongly.

The braking device of the present disclosure includes, for example, an operating member that moves the braking member between a braking position in which the braking member is in a braking state and a non-braking position in which the braking member is in a non-braking state, and a male screw and a female screw that mesh with each other. It has a shaft provided with one of the screws, a flange protruding radially outward from the shaft, and a peripheral wall protruding from the peripheral edge of the flange in the first direction along the axial direction of the shaft. A bottomed recess surrounded by a flange and the peripheral wall and opened in the first direction is provided, and a rotating member that rotates in conjunction with the rotor of the motor and the other screw of the male and female threads are provided. It moves linearly in the first direction according to the forward rotation of the above, and also linearly moves in the second direction opposite to the first direction according to the inversion of the rotating member, and causes the operating member to move to the braking position and the braking position. A linear motion member that can move between the non-braking position separated from the second direction and a bottomed recess that extends along the circumferential direction of the male screw and has an outer peripheral surface and a surface of the male screw. It has an inner peripheral portion that extends along the circumferential direction and faces the inner peripheral surface of the peripheral wall and is separated from the inner peripheral surface in a state of maximum axial deviation in the radial direction with respect to the male screw. It is configured in an annular shape, and includes an elastic member that can be sandwiched between the flange and the linear motion member as the linear motion member moves in the second direction.

According to the brake device, for example, a change in the posture of the elastic member due to contact between the outer peripheral portion of the elastic member and the inner peripheral surface of the peripheral wall can be prevented. Further, it is unlikely that variations in compression reaction force related to changes in the posture of the elastic member will occur. Therefore, according to such a configuration, for example, the desired compressive reaction force of the elastic member can be easily obtained. Then, it is possible to reliably prevent one screw of the rotating member and the other screw of the linear motion member from being too tightly fastened.

FIG. 1 is an exemplary and schematic rear view of the brake device of the embodiment as viewed from the rear of the vehicle. FIG. 2 is an exemplary and schematic cross-sectional view of the electric actuator of the braking device of the embodiment, and is a view in a non-braking state. FIG. 3 is an enlarged view of the rotary linear motion conversion mechanism of FIG. FIG. 4 is an enlarged view of the rotary linear motion conversion mechanism of FIG. 2, which is a state in which the linear motion member is in contact with the elastic member.

Hereinafter, exemplary embodiments of the present invention will be disclosed. The configurations of the embodiments shown below, as well as the actions and effects produced by the configurations, are examples. The present invention can also be realized by configurations other than those disclosed in the following embodiments. Further, according to the present invention, it is possible to obtain at least one of various effects (including derivative effects) obtained by the configuration.

In this specification, the ordinal number is used only for distinguishing parts, members, parts, positions, directions, and the like. This ordinal does not indicate the order or priority. All drawings are schematic and exemplary.

[Embodiment]
FIG. 1 is a rear view of the brake device 2 for a vehicle from the rear of the vehicle. The arrow Y in FIG. 1 indicates the outside in the vehicle width direction. The arrow Z indicates the upper part of the vehicle.

As shown in FIG. 1, the brake device 2 is housed inside the peripheral wall 1a of the cylindrical wheel 1. The brake device 2 is a so-called drum brake. The brake device 2 includes two brake shoes 3 which are separated from each other in the front-rear direction. The two brake shoes 3 extend in an arc shape along the inner peripheral surface of a cylindrical drum rotor (not shown).

The drum rotor rotates integrally with the wheel 1 around the center of rotation C along the vehicle width direction, the direction Y in FIG. The brake device 2 moves the two brake shoes 3 so as to come into contact with the inner peripheral surface of the cylindrical drum rotor. As a result, the friction between the brake shoe 3 and the drum rotor brakes the drum rotor and thus the wheel 1. The brake shoe 3 is an example of a braking member.

The brake device 2 includes a wheel cylinder (not shown) that operates by hydraulic pressure and a motor 120 that operates by energization. These are actuators that move the brake shoe 3. The wheel cylinder and the motor 120 can each move two brake shoes 3. The wheel cylinder is used, for example, for braking during traveling. The motor 120 is used, for example, for braking during parking. The brake device 2 is an example of an electric parking brake. The motor 120 may be used for braking during traveling.

The brake device 2 is provided with a disk-shaped backing plate 4. The backing plate 4 is provided in a posture intersecting the rotation center C of the wheel 1. That is, the backing plate 4 spreads substantially along the direction intersecting the rotation center C, specifically, substantially along the direction orthogonal to the rotation center C.

The components of the brake device 2 are provided on both the outside and the inside of the backing plate 4 in the vehicle width direction. The backing plate 4 directly or indirectly supports each component of the braking device 2. Further, the backing plate 4 is connected to a connecting member (not shown) with the vehicle body. The connecting member is, for example, part of the suspension. A part of the suspension is an arm, a link, a mounting member, and the like. The brake device 2 can be used for both driving wheels and non-driving wheels.

The electric actuator 100 is fixed to the backing plate 4 in a state of protruding from the inner surface 4a of the backing plate 4 in the vehicle width direction to the side opposite to the brake shoe 3. The electric actuator 100 includes, for example, a housing 110, a motor 120, a speed reduction mechanism 130, a rotation linear motion conversion mechanism 140, a cable 150, a control device (not shown), and the like.

FIG. 2 is a cross-sectional view of the electric actuator 100 in a non-braking state. In each of the following figures, the direction D1 of the arrow is the axial direction of the rotation center Ax1 of the rotating member 141, and is the direction in which the end portion 150a of the cable 150 approaches the brake shoe 3. The direction D2 of the arrow is the axial direction of the rotation center Ax1 and is the direction in which the end portion 150a of the cable 150 is separated from the brake shoe 3.

Direction D2 is an example of the first direction. Direction D1 is an example of the second direction. Further, in the following description, unless otherwise specified, the axial direction of the rotation center Ax1 is referred to as an axial direction. The radial direction of the rotation center Ax1 is called the radial direction. The circumferential direction of the rotation center Ax1 is called the circumferential direction.

The electric actuator 100 pulls the brake shoe 3 in the direction D2 via the cable 150. As a result, the brake shoe 3 moves from the non-braking state to the braking state. The cable 150 penetrates a through hole (not shown) provided in the backing plate 4. The cable 150 is an example of an operating member.

As shown in FIG. 2, the cable 150 is provided so as to be movable between the non-braking position Pr and the braking position Pb. The non-braking position Pr may also be referred to as the release position. The non-braking position Pr is separated from the braking position Pb in the direction D1, that is, downward in FIG. The braking position Pb is separated from the non-braking position Pr in the direction D2, that is, upward in FIG. The cable 150, the cable end 151, and the linear motion member 142 move in the direction D1. The cable 150, the cable end 151, and the linear motion member 142 move in the direction D2.

The housing 110 houses a motor 120, a deceleration mechanism 130, a rotation linear motion conversion mechanism 140, an elastic member 170 described later, and the like. The housing 110 is configured, for example, by integrating a plurality of parts. The plurality of parts include a cover 111, a base 112, and the like. The housing 110 can be made of a metal material such as iron or aluminum alloy, or a synthetic resin material such as plastic.

The motor 120 has a case 121 and accommodating parts housed in the case 121. The accommodating parts include, for example, a stator (not shown), a rotor (not shown), a coil (not shown), a magnet, and the like (not shown) in addition to the output shaft 122. The output shaft 122 is a part of the rotor. The output shaft 122 projects from the case 121 in the direction D1. The motor 120 is controlled by a control device to rotate the rotor and the output shaft 122. The motor 120 may also be referred to as an actuator or a rotation source.

The reduction mechanism 130 includes a plurality of gears rotatably supported by the housing 110. The plurality of gears are, for example, the first gear 131, the second gear 132, and the third gear 133. The first gear 131, the second gear 132, and the third gear 133 rotate in conjunction with the output shaft 122. The speed reduction mechanism 130 may also be referred to as a rotation transmission mechanism or the like.

The first gear 131 rotates integrally with the output shaft 122 of the motor 120 around the rotation center Ax3. The center of rotation Ax3 is parallel to the center of rotation Ax1. The first gear 131 may be referred to as a drive gear. The first gear 131, the second gear 132, and the third gear 133 can be made of, for example, a metal material such as iron or an aluminum alloy, or a synthetic resin material such as plastic. Each gear 131 to 133 may include a portion of a metal material and a portion of a synthetic resin material.

The second gear 132 rotates around the rotation center Ax2 parallel to the rotation centers Ax1 and Ax3. The second gear 132 includes an input gear 132a and an output gear 132b. The input gear 132a meshes with the first gear 131. The number of teeth of the input gear 132a is larger than the number of teeth of the first gear 131. Therefore, the second gear 132 is decelerated to a rotation speed lower than that of the first gear 131. The output gear 132b is positioned so as to deviate from the input gear 132a in the direction D1. The second gear 132 may be referred to as an idler gear.

The third gear 133 meshes with the output gear 132b of the second gear 132. The third gear 133 rotates around the center of rotation Ax1. The number of teeth of the third gear 133 is larger than the number of teeth of the output gear 132b. Therefore, the deceleration by the third gear 133 has a lower rotation speed than the deceleration by the second gear 132. The third gear 133 may be referred to as a driven gear. The configuration of the reduction mechanism 130 is not limited to this example. The speed reduction mechanism 130 may be, for example, a rotation transmission mechanism other than a gear mechanism using a belt, a pulley, or the like.

FIG. 3 is an enlarged view of the rotary linear motion conversion mechanism 140 shown in FIG. As shown in FIGS. 2 and 3, the rotary linear motion conversion mechanism 140 includes a rotary member 141, a linear motion member 142, and a rotation stop member 143.

The rotating member 141 has, for example, a shaft 141a, a flange 141b, and a peripheral wall 141e. The shape of the shaft 141a is a cylinder centered on the rotation center Ax1. Inside the shaft 141a, a through hole 141c along the axial direction is provided. The rotation center Ax1 is an example of the central axis.

The shape of the flange 141b is annular and plate-like. The flange 141b projects radially outward from the shaft 141a. A peripheral wall 141e is provided on the peripheral edge of the flange 141b.

The shape of the peripheral wall 141e is a cylinder centered on the rotation center Ax1. The peripheral wall 141e projects from the flange 141b in the direction D2. The third gear 133 described above is provided on the outer peripheral surface 141e1 of the peripheral wall 141e. The rotation of the rotor of the motor 120 and the output shaft 122 is transmitted to the rotating member 141 via the speed reduction mechanism 130. The rotating member 141 rotates in conjunction with the rotor of the motor 120.

Further, the rotating member 141 is provided with a bottomed recess 141f surrounded by a flange 141b and a peripheral wall 141e and opened in the direction D2. The end surface 141b2 in the direction D2 of the flange 141b has a circular shape and a flat shape, and constitutes the bottom surface of the bottomed recess 141f. The inner peripheral surface 141e2 of the peripheral wall 141e has a cylindrical surface shape, and constitutes the inner peripheral surface of the bottomed recess 141f. An elastic member 170, which will be described later, is housed in the bottomed recess 141f.

The shaft 141a has a first extension portion 141a1 extending from the flange 141b in the direction D2 and a second extension portion 141a2 extending from the flange 141b in the direction D1. The length of the first extension portion 141a1 is longer than the length of the second extension portion 141a2.

A male screw 141d is provided on the outer peripheral surface 141a3 of the first extension portion 141a1. The center of the male screw 141d is the rotation center Ax1. The center of rotation Ax1 may also be referred to as the axis.

A radial bearing 161 such as a slide bush or a roller bearing is provided between the outer circumference of the second extension portion 141a2 and the inner circumference of the through hole 112a of the base 112 shown in FIG. Further, a thrust bearing 162 such as a roller bearing is provided between the end surface 141b1 in the direction D1 of the flange 141b and the end surface 112b in the direction D2 of the base 112.

The rotating member 141 is rotatably supported by the base 112 around the center of rotation Ax1 via these radial bearings 161 and thrust bearings 162. The rotating member 141 is rotationally driven by the second gear 132 by meshing the second gear 132 and the third gear 133 of the reduction gear mechanism 130.

The third gear 133 is made integrally with the rotating member 141 by, for example, a metal material such as iron or an aluminum alloy. The third gear 133 is not limited to this example, and may be made of, for example, a synthetic resin material such as plastic. In this case, the third gear 133 can be integrated with the rotating member 141 made of a metal material by insert molding or the like.

As shown in FIG. 3, the linear motion member 142 has, for example, a side wall 142a and a flange 142b. The side wall 142a is arranged radially outward with respect to the rotating member 141 and extends in the axial direction. The side wall 142a surrounds the rotation center Ax1 and the rotation member 141.

The shape of the side wall 142a is a cylinder centered on the rotation center Ax1. The side wall 142a may also be referred to as a peripheral wall. Inside the side wall 142a, a through hole 142c is provided along the axial direction. The rotating member 141 penetrates through the through hole 142c in the axial direction.

The shape of the flange 142b is polygonal and plate-like. The flange 142b projects radially outward from the side wall 142a.

The side wall 142a has a first extension 142a1 extending from the flange 142b in the direction D2 and a second extension 142a2 extending from the flange 142b in the direction D1. The first extension 142a1 is longer than the second extension 142a2.

On the inner surface of the through hole 142c, a female screw 142d that meshes with the male screw 141d of the rotating member 141 is provided. The female screw 142d is provided adjacent to the end of the through hole 142c in the direction D1. The female screw 142d is provided in a section from the end of the through hole 142c in the direction D1 to a position where it is aligned radially with the flange 142b. The female screw 142d is not provided at the end of the through hole 142c in the direction D2. Further, the flange 142b is surrounded by the detent member 143 shown in FIG.

The detent member 143 has a side wall 143a. The side wall 143a is arranged radially outward with respect to the flange 142b described above, and extends in the axial direction. The side wall 143a surrounds the rotation center Ax1 and the linear motion member 142, and the shape of the side wall 143a is tubular. The side wall 143a may also be referred to as a peripheral wall.

The detent member 143 is fixed to the housing 110. Specifically, the detent member 143 has a flange 143c provided with an opening (not shown). The flange 143c is connected to the base 112 by fixing a bolt penetrating the opening to the base 112 in a state of being in contact with the end surface (not shown) of the base 112.

A minute gap is provided between the inner surface 143a1 of the side wall 143a and the outer surface 142b1 of the flange 142b in a parallel state, and both the outer surface 142b1 and the inner surface 143a1 extend in a direction intersecting the circumferential direction.

Due to this structure, the rotation of the outer surface 142b1 around the rotation center Ax1 is restricted by the inner surface 143a1. As a result, the rotation of the linear motion member 142 is restricted by the detent member 143. Since both the outer surface 142b1 and the inner surface 143a1 extend in the axial direction, the inner surface 143a1 allows the outer surface 142b1 to move in the axial direction. That is, the detent member 143 can guide the linear motion member 142 along the axial direction, that is, the linear motion direction, while prohibiting the rotation of the linear motion member 142 around the rotation center Ax1. The inner surface 143a1 may also be referred to as a guide portion.

A bottom wall 143b is provided at the end of the direction D2 of the detent member 143. The bottom wall 143b projects radially inward from the side wall 143a. The bottom wall 143b is provided with a through hole 143b1 that penetrates in the axial direction. The bottom wall 143b has an annular and plate-like shape, and may also be referred to as an inward flange. The inner edge of the through hole 143b1 is arranged radially outside the side wall 142a of the linear motion member 142.

The cable 150 penetrates the through hole 141c of the rotating member 141 and extends in the axial direction. One end in the axial direction (not shown) is coupled to a movable member that operates the brake shoe 3. Further, a cable end 151 is coupled to an end portion 150a (upper end in FIG. 2) which is the other end in the axial direction. The cable 150 and cable end 151 can be made of, for example, a metallic material.

The cable end 151 has a tubular portion 151a and a flange 151b. The cable end 151 is fixed to the cable 150 by crimping the tubular portion 151a from the outside. The flange 151b projects radially outward from the side wall 142a of the linear motion member 142 and the through hole 143b1 of the detent member 143. The cable end 151, along with the cable 150, is an example of an actuating member. The cable end 151 is an example of a fixing member.

The cable end 151 and the linear motion member 142 are not integrated and are configured to be separable in the axial direction. Here, the cable 150 is pulled in the direction D1 (downward in FIG. 2) in which the brake shoe 3 is in the non-braking state by a return member (eg, an urging member, an elastic member) such as a spring (not shown). The electric actuator 100 is configured so that the urging force of the return member always acts on the cable 150 in the movement range of the cable 150, that is, the range of use of the brake.

The urging force of the return member decreases as it approaches the non-braking state from the braking state. Further, in the braking state, tension is generated in the cable 150 according to the rigidity of the drum brake. In such a configuration, a force is transmitted between the linear motion member 142 and the cable 150 via the cable end 151. Therefore, the cable end 151 can also be referred to as a transmission member.

The control device that controls the motor 120 is, for example, an electronic control unit (ECU). A part of the control device may be composed of hardware such as a central processing unit (CPU) that executes software and a controller. The control device may be composed entirely of hardware. The control device may also be referred to as a control unit.

In such a configuration, the rotation of the output shaft 122 of the motor 120 is transmitted to the rotating member 141 via the reduction mechanism 130. When the rotating member 141 rotates, it meshes with the male screw 141d of the rotating member 141 and the female screw 142d of the linear motion member 142. Then, the linear motion member 142 moves in the axial direction. This axial movement is due to the limitation of rotation of the outer surface 142b1 of the linear motion member 142 by the inner surface 143a1 of the detent member 143. Therefore, the cable 150 moves between the braking position Pb and the non-braking position Pr along the axial direction as the linear motion member 142 moves.

The output shaft 122 of the motor 120 controlled by the control device rotates in one direction. By this rotation, the cable 150 moves in the direction D2, and the brake shoe 3 is in the braking state. In this braking state, the tension of the cable 150 increases. As a result, the rotational load of the motor 120 increases, which in turn increases the drive current of the motor 120. Hereinafter, one direction is referred to as a braking rotation direction.

The control device detects that the cable 150 has reached the braking position Pb, for example, because the drive current of the motor 120 exceeds the threshold value. Then, at that time, the supply of the drive current to the motor 120 is stopped. As a result, the rotation of the output shaft 122 is stopped, and the cable 150 is located at the braking position Pb.

The output shaft 122 of the motor 120 controlled by the control device rotates in the other direction. Due to this rotation, the cable 150 moves from the braking position Pb to the direction D1 and moves to the non-braking position Pr. At the non-braking position P, the cable end 151 comes into contact with the bottom wall 143b of the detent member 143. In this state, the brake shoe 3 is separated from the drum rotor, and the electric braking state by the electric actuator 100 is released. Hereinafter, the other is referred to as a release rotation direction.

The bottom wall 143b restricts the cable end 151 from moving beyond the bottom wall 143b in the direction opposite to the braking position Pb from the non-braking position Pr, that is, in the direction D1. The detent member 143 is an example of a stopper. The bottom wall 143b can also be referred to as a positioning portion that positions the cable 150 at the non-braking position Pr. The detent member 143 may also be referred to as a movement restricting member.

Further, as described above, in the present embodiment, the cable end 151 and the linear motion member 142 are not integrated and can be separated in the axial direction. Therefore, when the output shaft 122 further rotates in the release rotation direction from the state where the cable 150 is arranged at the non-braking position Pr, the linear motion member 142 is separated from the cable end 151 in the direction D1. This is due to the meshing of the male screw 141d and the female screw 142d and the detent of the linear motion member 142 by the detent member 143. That is, in a state where the cable 150 is arranged at the non-braking position Pr and the operation of the motor 120 is stopped, there is an axial gap between the linear motion member 142 and the cable end 151.

The control device measures the time during which the motor 120 is rotated from the state where the cable 150 is at the braking position Pb, that is, the rotation time, and the number of rotations of the output shaft 122. Utilizing these measurement results, the operation of the motor 120 is stopped at a position where the linear motion member 142 is separated from the cable end 151 in the direction D1. At this time, the rotation time and the number of rotations are set so that there is a more reliable gap between the stopped linear motion member 142 and the flange 141b of the rotary member 141 separated from the linear motion member 142 in the direction D1, in other words, the flange 141b. It is set so that it does not touch or interfere.

Further, the electric actuator 100 has a rotating member 141 and a guide member 113 adjacent to the direction D1. The guide member 113 has an annular shape and guides the cable 150 inside the through hole 112a of the base 112. The guide member 113 is made of, for example, an elastomer or a synthetic resin material.

As described above, the rotary linear motion conversion mechanism 140 has a screw mechanism including a male screw 141d and a female screw 142d. In the rotary linear motion conversion mechanism 140 having a screw mechanism, for example, the linear motion of the linear motion member 142 may be restricted for some reason. In this case, the male screw 141d and the female screw 142d may be in the fastened state. As an example, the linear motion member 142 may move in the direction D1 beyond the normal movable range in FIGS. 2 and 3 due to a malfunction of the control device or the like, and may come into contact with the flange 141b of the rotary member 141.

In this case, the fastened state can be eliminated by rotating the rotor of the motor 120 in the direction of rotation opposite to the rotation direction before the fastened state. However, the stronger the tightening, the more the torque of the motor 120 required to release the fastened state needs to be increased. That is, the power consumption of the motor 120 increases. Further, the size of the motor 120, which is premised on the release of such a fastening state, tends to increase, which in turn contributes to the increase in size of the brake device 2.

Therefore, in the present embodiment, a fail-safe structure is provided in which the elastic member 170 is arranged between the flange 141b of the rotating member 141 and the end portion 142f of the linear motion member 142 in the direction D1. Then, when the linear motion member 142 is returned too much in the direction D1, the elastic member 170 is sandwiched between the end portion 142f and the flange 141b, thereby reducing the fastening torque between the male screw 141d and the female screw 142d. .. The end portion 142f is an example of the first end portion. The fail-safe structure can also be referred to as a buffer structure.

FIG. 4 is an enlarged view of the rotary linear motion conversion mechanism 140 of FIG. FIG. 4 shows a state in which the linear motion member 142 is in contact with the elastic member 170. As shown in FIGS. 3 and 4, the elastic member 170 has, for example, an annular and plate-like shape centered on the rotation center Ax1. The elastic member 170 is made of a thermoplastic elastomer such as a polyester elastomer. The shape of the elastic member 170 in the free state is a flat plate.

The elastic member 170 is not limited to this example, and may have a C-shaped shape when viewed in the axial direction, for example. Further, it may be in a plate shape that is not a flat plate in a free state, or may not be in a plate shape. Further, for example, the cross-sectional shape on the virtual plane extending in the axial direction is not limited to the rectangle as in the above embodiment in the free state, and for example, a polygon other than a square or a quadrangle, a circle, an ellipse, or the like is adopted. You may.

The elastic member 170 has an inner peripheral portion 170a, an outer peripheral portion 170b, and two end faces 170c and 170d. The inner peripheral portion 170a and the outer peripheral portion 170b have a cylindrical surface shape. The end faces 170c and 170d have an annular and planar shape. The end face 170c extends between the ends of the inner peripheral portion 170a and the outer peripheral portion 170b in the direction D2. The end face 170d extends between the ends of the inner peripheral portion 170a and the outer peripheral portion 170b in the direction D1.

The elastic member 170 is housed in the bottomed recess 141f of the rotating member 141. The outer peripheral portion 170b faces the inner peripheral surface 141e2 of the peripheral wall 141e. The inner peripheral portion 170a faces the outer peripheral surface 141a3 of the male screw 141d. In the present embodiment, the diameter d1 of the outer peripheral portion 170b is set smaller than the diameter d3 of the inner peripheral surface 141e2. The diameter d2 of the inner peripheral portion 170a is set to be larger than the diameter d4 of the male screw 141d (shaft 141a).

The state P1 is a state in which the elastic member 170 is arranged concentrically with respect to the male screw 141d (see FIG. 4). The state P2 is a state in which the elastic member 170 is radially deviated from the male screw 141d and the inner peripheral portion 170a is in contact with the male screw 141d. Specifically, the outer peripheral portion 170b is set to a size that does not come into contact with the inner peripheral surface 141e2 in the range between the states P1 and the state P2.

In the present embodiment, such a configuration can prevent a change in posture, inclination, or wear of the elastic member 170 due to contact between the outer peripheral portion 170b and the inner peripheral surface 142e. Further, it is unlikely that variations in compression reaction force will occur. The state P1 is an example of the minimum axis deviation state. The state P2 is an example of the maximum axis deviation state. Further, the state between the states P1 and the state P2 is an example of the intermediate axis deviation state.

The shaft 141a is provided with an incompletely threaded portion 141ac facing the inner peripheral portion 170a. The incompletely threaded portion 141ac is provided in a diameter-expanded portion located at the end of the direction D1 of the male screw 141d. The incompletely threaded portion 141ac is located between the root portion 141ab of the shaft 141a adjacent to the direction D2 with respect to the flange 141b and the fully threaded portion of the male screw 141d.

The incompletely threaded portion 141ac is inclined so as to spread outward in the radial direction from the root portion 141ab toward the male screw 141d. That is, the diameter d4 of the male screw 141d is larger than the diameter of the root portion 141ab. The shaft 141a is provided with a flange 141b and a recess 141ad adjacent to the direction D2 by the root portion 141ab and the incompletely threaded portion 141ac.

Further, in the present embodiment, the axial length of the recess 141ad composed of the root portion 141ab and the incompletely threaded portion 141ac is set to be larger than the axial thickness W1 (see FIG. 3) of the elastic member 170. Has been done. Therefore, in a state where the inner peripheral portion 170a has entered the inside of the recess 141ad (for example, the above-mentioned state P2), the movement of the elastic member 170 in the direction D2 is prevented by being caught by the incompletely threaded portion 141ac. As a result, the movement of the elastic member 170 with respect to the bottomed recess 141f in the direction D2 is suppressed. The incompletely threaded portion 141ac is an example of a hooking portion.

In the present embodiment, the axial thickness W1 of the elastic member 170 is set to be larger than one pitch of the male screw 141d. As a result, the elastic member 170 enters the spiral groove portion of the male screw 141d. As a result, the elastic member 170 is suppressed from being held in an inclined posture. The incompletely threaded portion 141ac is also referred to as the end of the fully threaded portion of the male thread 141d. The root portion 141ab is also referred to as a constricted portion.

Further, the end portion 142f of the linear motion member 142 is provided with an end surface 142f1 and an inclined surface 142f2. The end face 142f1 has a planar and annular shape orthogonal to the axial direction. The end face 142f1 faces the end face 170c of the elastic member 170.

In the present embodiment, there are a state P1, a state P2, and a state between the state P1 and the state P2 of the elastic member 170 described above. Then, in the present embodiment, in all of these states, the entire surface of the end face 142f1 is configured to be able to come into contact with the end face 170c of the elastic member 170. This prevents the elastic member 170 from having a region that does not come into contact with the end face 142f1 and causing variations in the compression reaction force in the axial direction.

The inclined surface 142f2 is configured by, for example, chamfering a corner portion of the end surface 142f1. The inclined surface 142f2 is inclined so as to spread outward in the radial direction toward the direction D2. In the present embodiment, wear of the end surface 170c of the elastic member 170 can be prevented by eliminating the corner portion of the end surface 142f1 by the inclined surface 142f2. The inclined surface 142f2 is also referred to as a C surface, a tapered surface, or the like.

Further, in the present embodiment, the area or width of the end surface 142f1 is made relatively small by the above-mentioned inclined surface 142f2. As a result, the facing area and the contact area between the end face 142f1 and the end face 170c of the elastic member 170 are reduced, and the linear motion member 142 is separated from the end face 170c in the contacted state or the contacted state in the direction D2. Can be prevented. The end face 170c and the end face 170d of the elastic member 170 may be surface-treated.

As described above, in the present embodiment, the brake device 2 is housed in the bottomed recess 141f of the rotating member 141. The inner peripheral portion 170a extends along the circumferential direction of the shaft 141a (male screw 141d) and faces the outer peripheral surface 141a3 of the male screw 141d. The outer peripheral portion 170b extends along the circumferential direction of the shaft 141a. Further, the outer peripheral portion 170b faces the inner peripheral surface 141e2 of the peripheral wall 141e. In addition, the outer peripheral portion 170b is separated from the inner peripheral surface 141e2 in the state P2 with respect to the male screw 141d, that is, the maximum axis deviation state. The brake device 2 is configured in an annular shape having an inner peripheral portion 170a and an outer peripheral portion 170b. The brake device 2 includes an elastic member 170 that can be sandwiched between the flange 141b and the linear motion member 142 as the linear motion member 142 moves in the direction D1, that is, the second direction.

According to the brake device 2, for example, the posture change or inclination of the elastic member 170 due to the contact between the outer peripheral portion 170b and the inner peripheral surface 142e can be prevented. Therefore, it is unlikely that the compression reaction force will vary due to the change in the posture of the elastic member 170. According to such a configuration, for example, the desired compression reaction force of the elastic member 170 can be easily obtained. As a result, it is possible to more reliably prevent the male screw 141d of the rotating member 141 and the female screw 142d of the linear motion member 142 from being too tightly fastened.

In this embodiment, the elastic member 170 is composed of a thermoplastic elastomer. According to such a configuration, durability and moldability are improved as compared with the case where the elastic member 170 is made of crosslinked rubber, vulcanized rubber, or the like, for example. Then, it is possible to further prevent the male screw 141d and the female screw 142d from being fastened together.

In the present embodiment, the elastic member 170 has a flat plate shape in a free state. According to such a configuration, for example, as compared with the case where the elastic member 170 is composed of a disc spring, it is easy to obtain miniaturization in the axial direction, weight reduction, noise suppression effect, and the like. Further, as in the present embodiment, a non-coiled elastic member 170 can be used. As a result, for example, it becomes easy to reduce the arrangement space of the elastic member 170 in the free state in the axial direction.

In the present embodiment, the thickness W1 of the elastic member 170 along the axial direction is larger than one pitch of the male screw 141d. According to such a configuration, for example, the elastic member 170 is prevented from entering the spiral groove portion of the male screw 141d and being held in an inclined posture. Further, it is easier to prevent variations in the compression reaction force due to changes in the posture of the elastic member 170.

In the present embodiment, the rotating member 141 is provided on the outer peripheral surface 141e1 of the peripheral wall 141e, and has a third gear 133 to which a driving force is transmitted from the rotor of the motor 120. Such a configuration enables simplification of the manufacturing process, cost reduction, and miniaturization of the rotating member 141 as compared with a configuration in which the peripheral wall 141e is provided separately from the peripheral wall 141e constituting the third gear 133, for example. Become.

In the present embodiment, the linear motion member 142 has an end surface 142f1 facing the elastic member 170 and orthogonal to the axial direction. The linear motion member 142 may be in a state P1 with respect to the male screw 141d of the elastic member 170, that is, a minimum axis deviation state, a state P2, and a state between the state P2 and the state P1, that is, an intermediate axis deviation state. In all of these states, the entire surface of the end face 142f1 is configured to be in contact with the elastic member 170. According to such a configuration, for example, it is possible to prevent the elastic member 170 from having a region that does not come into contact with the end face 142f1 and causing variation in the compression reaction force in the axial direction. Then, it is possible to further prevent the male screw 141d and the female screw 142d from being fastened together.

In the present embodiment, the shaft 141a has a root portion 141ab adjacent to the direction D2, that is, the first direction with respect to the flange 141b, and an elastic member 170 projecting radially outward on the side opposite to the flange 141b of the root portion 141ab. It has an incomplete threaded portion 141ac, that is, a hooking portion, which suppresses the movement of the bottomed recess 141f in the direction D2. According to such a configuration, for example, the elastic member 170 tends to stay in the bottomed recess 141f due to the incompletely threaded portion 141ac.

Although the embodiment of the present invention has been exemplified, the above embodiment is an example and is not intended to limit the scope of the invention. The above embodiment can be implemented in various other forms. In the above embodiment, various omissions, replacements, combinations, and changes can be made without departing from the gist of the invention. In addition, specifications such as each configuration and shape (structure, type, direction, shape, size, length, width, thickness, height, number, arrangement, position, material, etc.) are changed as appropriate. Can be carried out.

For example, the rotating member may be provided with a female screw, and the linear motion member may be provided with a male screw. Further, for example, a plurality of elastic members may be laminated in the bottomed recess. Further, for example, the linear motion member may be provided with a bottomed recess.

Claims

An actuating member that moves the braking member between a braking position in which the braking member is in the braking state and a non-braking position in which the braking member is in the non-braking state.
A shaft provided with one of a male screw and a female screw that mesh with each other, a flange protruding radially outward from the shaft, and a peripheral wall protruding from the peripheral edge of the flange in the first direction along the axial direction of the shaft. A rotating member that has a, and is surrounded by the flange and the peripheral wall and is provided with a bottomed recess that opens in the first direction and rotates in conjunction with the rotor of the motor.
The other screw of the male screw and the female screw is provided, and linearly moves in the first direction according to the forward rotation of the rotating member and in the second direction opposite to the first direction according to the reversal of the rotating member. A linearly moving member that moves linearly to and can move the operating member between the braking position and a non-braking position that is separated from the braking position in the second direction.
It is housed in the bottomed recess and extends along the circumferential direction of the male screw and faces the outer peripheral surface of the male screw, and extends along the circumferential direction and faces the inner peripheral surface of the peripheral wall. It is formed in an annular shape having an outer peripheral portion separated from the inner peripheral surface in a state of maximum axial deviation in the radial direction with respect to the male screw, and the flange and the flange are formed as the linear motion member moves in the second direction. An elastic member that can be sandwiched between the linear motion member and
With a braking device.
The brake device according to claim 1, wherein the elastic member is composed of a thermoplastic elastomer.
The brake device according to claim 1 or 2, wherein the elastic member has a flat plate shape in a free state.
The brake device according to any one of claims 1 to 3, wherein the thickness of the elastic member along the axial direction is larger than one pitch of one of the screws.
The brake device according to any one of claims 1 to 4, wherein the rotating member is provided on an outer peripheral surface of the peripheral wall and has a gear to which a driving force is transmitted from the rotor.
The linear motion member has an end face facing the elastic member and orthogonal to the axial direction.
In the radial minimum axis deviation state, the maximum axis deviation state, and the intermediate axis deviation state between the maximum axis deviation state and the minimum axis deviation state with respect to the male screw of the elastic member, the entire surface of the end face is covered. The brake device according to any one of claims 1 to 5, which is configured to be in contact with the elastic member.
The shaft of the rotating member is provided with the male screw, and the shaft has a root portion adjacent to the flange in the first direction and a root portion of the root portion opposite to the flange and outward in the radial direction. The braking device according to any one of claims 1 to 6, further comprising a hooking portion that projects and suppresses the movement of the elastic member with respect to the bottomed recess in the first direction.