CN111356857A

CN111356857A - Brake device

Info

Publication number: CN111356857A
Application number: CN201880074407.5A
Authority: CN
Inventors: 佐佐木阳成; 山田仁; 稻葉卓也
Original assignee: Advics Co Ltd
Current assignee: Advics Co Ltd
Priority date: 2017-12-27
Filing date: 2018-12-13
Publication date: 2020-06-30
Anticipated expiration: 2038-12-13
Also published as: JP2019116965A; DE112018006711T5; WO2019131153A1; JP6984406B2; CN111356857B

Abstract

The electric actuator of the brake device is attached to the back plate in a state where the motion conversion mechanism protrudes from a surface of the back plate opposite to the brake member, and the rotating member is rotationally driven by a ring gear provided on an outer periphery of the rotating member and rotating in conjunction with the output shaft.

Description

Brake device

Technical Field

The present invention relates to a brake device.

Background

Conventionally, there is known a brake device including a motion conversion mechanism having a rotating member that rotates in conjunction with an output shaft of a motor and a linearly moving member that linearly moves in accordance with the rotation of the rotating member, and braking is performed by pulling a cable by the linearly moving member to move a brake shoe (for example, patent documents 1 and 2). In patent document 1, a linearly moving member having a male screw linearly moves in accordance with the rotation of a rotating member having a female screw. In patent document 2, a member for transmitting rotation of an output shaft of a motor is connected to a shaft end surface of a rotating member located on a far side from a brake shoe.

Documents of the prior art

Patent document

Patent document 1: japanese Kokai publication Hei 2014-504711

Patent document 2: german DE102007002907A1 publication

Disclosure of Invention

Technical problem to be solved by the invention

In the brake device in which the linearly moving member having the male screw linearly moves in accordance with the rotation of the rotating member having the female screw as in patent document 1, the diameter of the bearing supporting the rotating member is likely to increase, and thus the brake device may be increased in size.

Further, in the brake device in which the output shaft of the motor or the member that rotates in conjunction with the output shaft is connected to the axial end surface of the rotating member of the motion conversion mechanism as in patent document 2, the brake device may be increased in size in the axial direction.

Therefore, one of the technical problems of the present invention is to obtain a brake device having a novel structure which is less likely to cause troubles, for example, to be further miniaturized.

Technical solution for solving technical problem

The brake device of the present invention includes, for example: a braking member that is pressed against a drum rotor that rotates integrally with a wheel, thereby braking the drum rotor; a back plate supporting the braking member; and an electric actuator provided to the back plate and operating the brake member; wherein the electric actuator includes: a motor having an output shaft that rotates; a motion conversion mechanism including a rotating member having a male screw and rotating around an axis of the male screw in conjunction with the output shaft, and a linearly moving member having a female screw engaged with the male screw and linearly moving in accordance with rotation of the rotating member; and an actuating member that receives a force for actuating the braking member from the linear moving member; the electric actuator is attached to the back plate in a state where the motion conversion mechanism protrudes from a surface of the back plate opposite to the brake member; the rotating member is rotationally driven by a ring gear provided on an outer periphery of the rotating member and rotating in conjunction with the output shaft.

According to such a configuration, for example, compared to a form in which a linearly moving member having a male screw moves linearly in accordance with rotation of a rotating member having a female screw as in patent document 1, there are advantages as follows: since the diameter of the bearing supporting the rotating member is easily reduced, the electric actuator can be further downsized in the radial direction, and the sliding speed of the bearing at the same rotation speed is further reduced by further reducing the diameter of the bearing, so that the durability such as wear resistance is easily improved. Further, according to the above configuration, for example, compared to a form in which the output shaft of the motor or a member that rotates in conjunction with the output shaft is connected to the axial end surface of the rotating member of the motion conversion mechanism as in patent document 2, there is an advantage in that the overall length of the electric actuator can be easily further shortened. Therefore, according to the above configuration, for example, in the brake device in which the electric actuator is attached to the back plate in a state of protruding from the surface of the back plate opposite to the brake member, there can be obtained an advantage that the vehicle-mounted space is easily secured by downsizing the electric actuator as described above, and an advantage that the durability can be improved.

Drawings

Fig. 1 is an exemplary and schematic rear view of a brake device of an embodiment as viewed from the rear side of a vehicle.

Fig. 2 is an exemplary and schematic side view of the brake device of the embodiment as viewed from the outside in the vehicle width direction.

Fig. 3 is an exemplary and schematic side view of the movement mechanism of the brake device according to the embodiment, showing the operation of the brake member in a non-braking state.

Fig. 4 is an exemplary and schematic side view of the movement mechanism of the brake device according to the embodiment, showing the operation of the brake member in the braking state.

Fig. 5 is an exemplary and schematic cross-sectional view of an electric actuator of the embodiment, which is a view in a non-braking state.

Fig. 6 is an exemplary and schematic cross-sectional view of a part of the electric actuator according to the embodiment, and is a view in which the operating member is in a braking position.

Fig. 7 is an exemplary and schematic cross-sectional view of a part of the electric actuator according to the embodiment, and is a diagram showing a state at a time point when the operating member reaches the release position from the braking position.

Fig. 8 is an exemplary and schematic cross-sectional view of a part of the electric actuator according to the embodiment, and is a view in a state where the operation member has reached the release position and the rotation of the motor has stopped.

Fig. 9 is an exemplary and schematic perspective view of a movement restricting member included in the electric actuator of the embodiment.

Fig. 10 is an exemplary and schematic perspective view of a linear moving member included in the electric actuator of the embodiment.

Fig. 11 is an exemplary and schematic perspective view of a part of a motion conversion mechanism included in the electric actuator of the embodiment.

Fig. 12 is an exemplary and schematic cross-sectional view of a part of an electric actuator according to a first modification, and is a view in a non-braking state.

Fig. 13 is an exemplary and schematic cross-sectional view of a part of an electric actuator according to a second modification, which is a view in a non-braking state.

Fig. 14 is an exemplary and schematic perspective view of a movement restricting member included in an electric actuator of a third modification.

Detailed Description

Hereinafter, exemplary embodiments of the present invention are disclosed. The configurations of the embodiments and the modifications described below, and the operation and the result (effect) obtained by the configurations are examples. The present invention can be realized by other configurations than those disclosed in the following embodiments and modifications. In addition, according to the present invention, at least one of various effects (including derived effects) obtained by the configuration can be obtained.

The following embodiments and modifications include the same components. Therefore, in the following description, the same components are given the same reference numerals, and redundant description thereof may be omitted. In the present specification, the reference numerals are given for convenience of distinguishing components, parts, and the like, and do not indicate the order of priority or sequence.

In each drawing, an arrow D1 indicates a direction in which the end portion 150a (one end) of the cable 150 is separated from the brake member in the axial direction of the third rotation center Ax3, and an arrow D2 indicates a direction in which the end portion 150a is close to the brake member in the axial direction of the third rotation center Ax 3. In the following description, unless otherwise specified, the axial direction of the third rotation center Ax3 is simply referred to as the axial direction, the radial direction of the third rotation center Ax3 is simply referred to as the radial direction, and the circumferential direction of the third rotation center Ax3 is simply referred to as the circumferential direction.

[ embodiment ] A method for producing a semiconductor device

[ Structure of brake device ]

Fig. 1 is a rear view of a vehicle brake device 2 as viewed from the rear side of the vehicle. Fig. 2 is a side view of the brake device 2 as viewed from the outside in the vehicle width direction. Fig. 3 is a side view showing the operation of the brake shoe 3 (brake member) by the moving mechanism 8 of the brake device 2, and is a view in a non-braking state. Fig. 4 is a side view showing the operation of the brake shoe 3 by the moving mechanism 8 of the brake device 2, and is a view in a braking state.

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. As shown in fig. 2, the brake device 2 includes two brake shoes 3 separated in the front-rear direction. As shown in fig. 3 and 4, the two brake shoes 3 extend in an arc shape along the inner circumferential surface 4a of the cylindrical drum rotor 4. The drum rotor 4 rotates integrally with the wheel 1 around a rotation center C along the vehicle width direction (Y direction). The brake device 2 moves the two brake shoes 3 so as to contact the inner circumferential surface 4a of the cylindrical drum rotor 4. The drum rotor 4 and the wheel 1 are thereby braked by friction between the brake shoe 3 and the drum rotor 4. The brake shoe 3 is an example of a brake member.

The brake device 2 includes a wheel cylinder 51 (see fig. 2) that is operated by hydraulic pressure and a motor 120 that is operated by energization as an actuator for moving the brake shoes 3. The wheel cylinder 51 and the motor 120 can move both the brake shoes 3. The wheel cylinder 51 is used for braking during traveling, for example, and the motor 120 is used for braking during parking, for example. That is, the brake device 2 is an example of an electric parking brake. Further, the motor 120 may also be used for braking during traveling.

As shown in fig. 1 and 2, the braking device 2 includes a disc-shaped back plate 6. The back plate 6 is disposed in a posture intersecting the rotation center C. That is, the back plate 6 extends substantially in a direction intersecting the rotation center C, specifically, substantially in a direction orthogonal to the rotation center C. As shown in fig. 1, the components of the brake device 2 are provided on both the outer side and the inner side of the back panel 6 in the vehicle width direction. The back plate 6 directly or indirectly supports the structural components of the brake device 2. That is, the back plate 6 is an example of the support member. The back panel 6 is connected to a connection member, not shown, of the vehicle body. The connecting member is, for example, a part of a suspension (e.g., an arm, a link, a mounting member, etc.). The opening 6b provided in the back plate 6 shown in fig. 2 is used for coupling with the connecting member. The brake device 2 can be used for any of the driving wheels and the non-driving wheels. When the brake device 2 is used for a drive wheel, an axle, not shown, penetrates through the opening 6c of the back plate 6 shown in fig. 2.

[ brake shoe action based on wheel cylinder ]

The wheel cylinder 51, the brake shoe 3, and the like shown in fig. 2 are disposed on the vehicle width direction outer side of the back plate 6. The brake shoe 3 is movably supported by the backing plate 6. Specifically, as shown in fig. 3, the lower end portion 3a of the brake shoe 3 is rotatably supported by the backing plate 6 (see fig. 2) about a rotation center C11. The rotation center C11 is substantially parallel to the rotation center C of the wheel 1. As shown in fig. 2, the wheel cylinder 51 is supported by the upper end of the back plate 6. The wheel cylinder 51 has two movable portions (pistons), not shown, that can protrude in the vehicle front-rear direction (the left-right direction in fig. 2). The wheel cylinder 51 projects the two movable portions in response to the pressure. The two projecting movable portions press the upper end portions 3b of the brake shoes 3, respectively. By the protrusion of the two movable portions, the two brake shoes 3 are respectively rotated about the rotation center C11 (refer to fig. 3, 4), and the upper end portions 3b are moved to be separated from each other in the vehicle front-rear direction. Thereby, the two brake shoes 3 move radially outward of the rotation center C of the wheel 1. A band-shaped lining 31 along a cylindrical surface is provided on the outer periphery of each brake shoe 3. Therefore, as shown in fig. 4, the lining 31 is in contact with the inner circumferential surface 4a of the drum rotor 4 by the movement of the two brake shoes 3 outward in the radial direction of the rotation center C. The drum rotor 4 and the wheel 1 (see fig. 1) are braked by friction between the lining layer 31 and the inner circumferential surface 4 a. As shown in fig. 2, the braking device 2 includes a return member 32. When the operation of pressing the brake shoes 3 by the wheel cylinder 51 is released, the returning means 32 moves the two brake shoes 3 from the position (braking position Psb, see fig. 4) in contact with the inner peripheral surface 4a of the drum rotor 4 to the position (non-braking position Psn, initial position, see fig. 3) not in contact with the inner peripheral surface 4a of the drum rotor 4. The return member 32 is an elastic member such as a coil spring, for example, and applies a force in a direction to move the other brake shoe 3 closer to the other brake shoe 3, i.e., a force in a direction away from the inner circumferential surface 4a of the drum rotor 4, to each brake shoe 3.

Structure of moving mechanism and movement of brake shoe based on moving mechanism

The braking device 2 includes a moving mechanism 8 shown in fig. 3 and 4. The moving mechanism 8 moves the two brake shoes 3 from the non-braking position Psn (fig. 3) to the braking position Psb (fig. 4) in accordance with the operation of the electric actuator 100 (see fig. 5) including the motor 120. The moving mechanism 8 is provided on the vehicle width direction outer side of the back panel 6. The moving mechanism 8 includes a swing lever (lever)81, a cable 150, and a strut (strut) 83. The swing link 81 is provided between one of the two brake shoes 3, for example, the left brake shoe 3L in fig. 3 and 4, and the back plate 6 so as to overlap the brake shoe 3L and the back plate 6 in the axial direction of the rotation center C of the wheel 1. The swing lever 81 is supported by the brake shoe 3L so as to be rotatable about the rotation center C12. The rotation center C12 is located at an end of the brake shoe 3L on a side far from the rotation center C11 (upper side in fig. 3 and 4), and is substantially parallel to the rotation center C11. The cable 150 moves the lower end 81a of the swing lever 81 on the side away from the rotation center C12 in the direction toward the other side, for example, the right brake shoe 3R in fig. 3 and 4. The cable 150 moves generally along the back panel 6. Further, a strut 83 is interposed between the swing lever 81 and another brake shoe 3R different from the brake shoe 3L supporting the swing lever 81, and is supported between the swing lever 81 and the other brake shoe 3R. Further, a connection position P1 of the lever 81 and the stay 83 is set between the rotation center C12, the end 150b (the other end) of the cable 150, and a connection position P2 of the lever 81. The cable 150 is an example of an operating member that moves the brake shoe 3.

In this moving mechanism 8, when the cable 150 is pulled and moved to the right side in fig. 4, and the swing lever 81 is moved in a direction to come close to the brake shoe 3R (arrow a), the swing lever 81 presses the brake shoe 3R via the strut 83 (arrow b). Thereby, the brake shoe 3R rotates (arrow C in fig. 4) about the rotation center C11 from the non-braking position Psn (fig. 3) and moves to the braking position Psb (fig. 4) in contact with the inner peripheral surface 4a of the drum rotor 4. In this state, the connection position P2 of the cable 150 and the lever 81 corresponds to a force point, the rotation center C12 corresponds to a fulcrum, and the connection position P1 of the lever 81 and the fulcrum 83 corresponds to an action point. Further, when the lever 81 is moved to the right side of fig. 4, that is, in a direction in which the lever 83 presses the brake shoe 3R (arrow b) in a state in which the brake shoe 3R is in contact with the inner peripheral surface 4a, the lever 81 is supported by the lever 83, and thereby the lever 81 is rotated in a direction opposite to the moving direction of the lever 81, that is, in a counterclockwise direction in fig. 3 and 4, with the connecting position P1 with the lever 83 as a fulcrum (arrow d). Thereby, the brake shoe 3L rotates about the rotation center C11 from the non-braking position Psn (fig. 3), and moves to the braking position Psb (fig. 4) in contact with the inner peripheral surface 4a of the drum rotor 4. In this way, both the

brake shoes

3L and 3R are moved from the non-braking position Psn (fig. 3) to the braking position Psb (fig. 4) by the operation of the moving mechanism 8. Further, in a state after the brake shoe 3R comes into contact with the inner peripheral surface 4a of the drum rotor 4, a connection position P1 between the swing lever 81 and the strut 83 serves as a fulcrum. The movement amount of the

brake shoes

3L and 3R is small, for example, 1mm or less.

[ ELECTRIC ACTUATOR ]

As shown in fig. 1, the electric actuator 100 is fixed to the back plate 6 in a state of protruding from the inner surface 6a of the back plate 6 in the vehicle width direction to the side opposite to the brake shoe 3.

Fig. 5 is a sectional view of the electric actuator 100 in a non-braking state. The electric actuator 100 pulls the brake shoe 3 (brake member) via the cable 150, and moves the brake shoe 3 from the non-braking position to the braking position. The cable 150 passes through the through hole 6d provided in the back plate 6. The cable 150 is an example of an operation member.

As shown in fig. 5, the electric actuator 100 includes a housing 110, a motor 120, a speed reduction mechanism 130, a motion conversion mechanism 140, a cable 150, and a control device 200.

The housing 110 supports the motor 120, the speed reduction mechanism 130, and the motion conversion mechanism 140. The housing 110 includes a main body 112 (base), a lower case 113, an inner cover 114, and an upper case 115. These are integrated by a not-shown coupling member such as a screw or by insert molding. A housing chamber R surrounded by a wall 111 of the housing 110 is provided in the housing 110. The motor 120, the speed reduction mechanism 130, and the motion conversion mechanism 140 are housed in the housing chamber R and covered by the wall portion 111. The housing 110 may be referred to as a base, a support member, a shell, etc. Further, the structure of the housing 110 is not limited to the structure illustrated herein.

The main body 112 may be made of a metal material such as an aluminum alloy. In this case, the main body 112 may be manufactured by, for example, die casting. The lower case 113, the inner case 114, and the upper case 115 are made of, for example, a synthetic resin material.

The motor 120 is an example of an actuator, and includes a housing 121 and a housing member housed in the housing 121. The housing member includes, for example, a stator, a rotor, a coil, a magnet (not shown), and the like, in addition to the output shaft 122. The output shaft 122 protrudes from the housing 121 in a direction D2 (right side in fig. 5) along the first rotation center Ax1 of the motor 120. The motor 120 is controlled by a control device such as an ECU (electronic control unit) to rotate an output shaft 122.

The reduction mechanism 130 includes a plurality of gears rotatably supported by the housing 110. The plurality of gears are, for example, a first gear 131, a second gear 132, and a third gear 133. The reduction mechanism 130 may be referred to as a rotation transmission mechanism.

The first gear 131 rotates integrally with the output shaft 122 of the motor 120. The first gear 131 may be referred to as a driving gear.

The second gear 132 rotates about a second rotational center Ax2 that is parallel to the first rotational center Ax 1. The second gear 132 includes an input gear 132a and an output gear 132 b. The input gear 132a meshes with the first gear 131. The input gear 132a has a larger number of teeth than the first gear 131. Therefore, the second gear 132 is decelerated to a lower rotation speed than the first gear 131. The output gear 132b is located on the rear side (left side in fig. 5) of the direction D1 with respect to the input gear 132 a. The second gear 132 may be referred to as an idler gear.

The third gear 133 rotates about a third rotation center Ax3 that is parallel to the first rotation center Ax 1. The third gear 133 is engaged with the output gear 132b of the second gear 132. The third gear 133 has a larger number of teeth than the output gear 132 b. Therefore, the third gear 133 is decelerated to a lower rotation speed than the second gear 132. The third gear 133 may be referred to as a driven gear. The third gear 133 is an example of a ring gear. Here, the ring gear refers to a ring gear, and in this embodiment, is external teeth. Further, the structure of the speed reducing mechanism 130 is not limited to the structure illustrated here. The speed reduction mechanism 130 may be a rotation transmission mechanism other than a gear mechanism, such as a rotation transmission mechanism using a belt, a pulley, or the like.

The motion conversion mechanism 140 includes a rotating member 141 and a linear movement member 142. Fig. 6 is an enlarged sectional view of the motion conversion mechanism 140. In fig. 5 and 6, the position of the cable 150 is different.

As shown in fig. 6, the rotating member 141 has a peripheral wall 141a and a flange 141 b. The peripheral wall 141a has a cylindrical shape with the third rotation center Ax3 as the center. A through hole 141c is provided in the peripheral wall 141a along the axial direction.

The flange 141b is annular and plate-like in shape. The flange 141b extends radially outward from the peripheral wall 141 a. A third gear 133 is provided on the outer periphery of the flange 141 b. That is, the rotating member 141 and the flange 141b may be referred to as a driven portion or a third gear.

The peripheral wall 141a has a first extending portion 141a1 extending from the flange 141b in the direction D1, and a second extending portion 141a2 extending from the flange 141b in the direction D2. The length of the first extension part 141a1 is longer than the length of the second extension part 141a 2.

An external thread 141d is provided on the outer periphery of the first extension 141a 1. The center of the external thread 141d is the third rotational center Ax 3. The third rotation center Ax3 is an example of the axial center.

A radial bearing 161 such as a slide bearing or a roller bearing is provided between the outer periphery of the second extending portion 141a2 and the inner periphery of the through hole 112a of the main body 112. A thrust bearing 162 such as a roller bearing is provided between the end face 141b1 of the flange 141b in the direction D2 and the end face 112b of the body 112 in the direction D1. The rotary member 141 is supported by the main body 112 so as to be rotatable about the third rotation center Ax3 by the radial bearing 161 and the thrust bearing 162. The rotating member 141 is rotationally driven by the second gear 132 based on the engagement of the second gear 132 and the third gear 133.

The third gear 133 is made of, for example, a synthetic resin material, and the disk 141b2 other than the third gear 133 in the peripheral wall 141a and the flange 141b may be made of, for example, a metal material such as iron or an aluminum alloy. In the present embodiment, iron is used as an example. In this case, the rotating member 141 may be formed by insert molding, for example. The rotating member 141 may further include a third gear 133 and be integrally formed of a metal material.

The linear moving member 142 has a side wall 142a and a flange 142 b. The side wall 142a is located radially outward of the rotating member 141 and extends in the axial direction. The side wall 142a surrounds the third rotation center Ax3 and the rotating member 141, and the side wall 142a is cylindrical with the third rotation center Ax3 as the center. The side wall 142a may also be referred to as a peripheral wall. A through hole 142c is provided in the side wall 142a along the axial direction. The rotating member 141 penetrates the through hole 142c in the axial direction.

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

The side wall 142a has a first extension 142a1 extending from the flange 142b in the direction D1, and a second extension 142a2 extending from the flange 142b in the direction D2. The length of the first extension 142a1 is longer than the length of the second extension 142a 2.

A female screw 142d that engages with the male screw 141d of the rotary member 141 is provided on the inner surface of the through hole 142 c. The female screw 142D is provided adjacent to an end of the through hole 142c in the direction D2. The female screw 142D is provided in a section from the end of the through hole 142c in the direction D2 to a position radially aligned with the flange 142b, and the female screw 142D is not provided at the end of the through hole 142c in the direction D1. Further, the flange 142b is surrounded by a rotation stopper 143 extending in the axial direction.

The rotation stopping member 143 has a side wall 143 a. The side wall 143a is located radially outward of the flange 142b and extends in the axial direction. The side wall 143a surrounds the third rotation center Ax3 and the rotation member 141, and the side wall 143a has a tubular shape. The side wall 143a may also be referred to as a peripheral wall.

The rotation stopper 143 is fixed to the housing 110 such as the main body 112 or the upper case 115. Further, a slight gap is provided between the outer surface 142b1 of the flange 142b and the inner surface 143a1 of the side wall 143a in a parallel state, and the outer surface 142b1 and the inner surface 143a1 both extend in a direction intersecting the circumferential direction.

Therefore, the rotation of the outer surface 142b1 about the third rotation center Ax3 is restricted by the inner surface 143a1, whereby the rotation of the linear moving member 142 is restricted by the rotation stop member 143. On the other hand, since both the outer surface 142b1 and the inner surface 143a1 extend in the axial direction, the inner surface 143a1 does not serve as an obstruction to the axial movement of the outer surface 142b 1. That is, the rotation preventing member 143 can guide the linear motion member 142 in the axial direction while preventing the linear motion member 142 from rotating around the third rotation center Ax 3. The inner surface 143a1 is an example of a guide portion.

A plurality of protrusions 143b protruding radially inward from the side wall 143a are provided at an end of the rotation stopper 142 in the direction D1. The inner end of the projection 143b is positioned radially outward of the side wall 142c of the linear motion member 142. Instead of the plurality of projections 143b, one annular projection (inward flange) may be provided along the circumferential direction.

The cable 150 penetrates the through hole 141c of the rotating member 141 and extends in the axial direction. One end (right end in fig. 6) in the axial direction is coupled to a movable member that operates the brake shoe 3. Further, a cable terminal 144 is coupled to an end 150a (left end in fig. 6) which is the other end in the axial direction. The cable end piece 144 has a cylindrical portion 144a and a flange 144 b. The cylindrical portion 144a is caulked from the outside, thereby coupling the cable 150 and the cable end piece 144. The flange 114b extends radially outward beyond the inner ends of the side wall 142a of the linear motion member 142 and the projection 143b of the rotation stop member 143.

The cable end 144 and the linear moving member 142 are not integrated with each other, and are configured to be axially separable. Here, the cable 150 is pulled in a direction (direction D2) in which the braking member is brought into a braking state by an elastic member (biasing member) such as a spring (not shown). Therefore, the cable end piece 144 presses the linearly moving member 142 in the direction D2. The electric actuator 100 is configured such that the urging force of the elastic member is always applied to the cable 150 in the movement range of the cable 150 (the use range of the brake). In addition, in the braking state, a tension corresponding to the rigidity of the braking device is generated in the cable 150. In this configuration, force is transmitted between the linearly moving member 142 and the cable 150 via the cable end piece 144. The cable end 144 is an example of a transmission member.

The control device 200 controls the motor 120. A part of the control device 200 may be configured by hardware such as a Central Processing Unit (CPU) or a controller that executes software, and the entire control device 200 may be configured by hardware. The control device 200 is an example of a control unit.

In this configuration, when the rotation of the output shaft 122 of the motor 120 is transmitted to the rotating member 141 via the reduction mechanism 130 and the rotating member 141 rotates, the linearly moving member 142 moves in the axial direction by the engagement of the male screw 141d of the rotating member 141 with the female screw 142d of the linearly moving member 142 and the restriction of the rotation of the outer surface 142b1 of the linearly moving member 142 by the inner surface 143a1 of the rotation stopping member 143. Therefore, the cable 150 moves between the braking position Pb and the releasing position Pr in the axial direction along with the movement of the linear moving member 142.

Fig. 6 is a sectional view of the motion conversion mechanism 140 in a state where the cable 150 is located at the braking position Pb, fig. 7 is a sectional view of the motion conversion mechanism 140 at a time point when the cable 150 reaches the releasing position Pr from the braking position Pb, and fig. 8 is a sectional view of the motion conversion mechanism 140 in a state where the cable 150 reaches the releasing position Pr and the rotation of the motor 120 is stopped.

When the output shaft 122 of the motor 120 controlled by the control device 200 rotates in one direction (hereinafter, referred to as a brake rotation direction), the cable 150 moves in the direction D1, and when the brake member is in the brake state, the tension of the cable 150 increases, the rotation load of the motor 120 increases, and the drive current of the motor 120 increases. Therefore, for example, control device 200 detects that cable 150 has reached brake position Pb when the drive current of motor 120 exceeds a threshold value, and stops supplying the drive current to motor 120 at that time. Thereby, the rotation of the output shaft 122 is stopped, and the cable 150 is located at the braking position Pb (fig. 6).

When the output shaft 122 of the motor 120 controlled by the control device 200 rotates in the other direction (hereinafter referred to as a release rotation direction), the cable 150 moves from the braking position Pb (fig. 6) to the direction D2, and the cable end 144 moves to the release position Pr (fig. 7) where it abuts against the projection 143b of the rotation stopper 143. In this state, the brake member is separated from the rotating member (not shown, for example, a brake drum), and the electric brake state by the electric actuator 100 is released. The projection 143b restricts the cable end piece 144 from moving in the direction D2 beyond the position of abutment with the projection 143 b. That is, the protrusion 143b is an example of a positioning portion that positions the cable 150 to the release position Pr, and the rotation stopper 143 is an example of a movement restricting member.

Further, in a state where the cable 150 is located at the release position Pr, a gap g is provided in the axial direction between the rotating member 141 and the cable end piece 144. Furthermore, it is not essential that the cable 150 is positioned to the release position Pr by the abutment of the protrusion 143b with the cable end piece 144 as described above. For example, it may be arranged that the release position Pr is determined by abutment of the swing lever 81 with other components or the like, in which case the projection 143b and the cable end piece 144 may not abut.

As described above, in the present embodiment, the cable end piece 144 and the linear movement member 142 are not integrated and can be separated in the axial direction. Therefore, when the output shaft 122 of the motor 120 is further rotated in the releasing rotation direction from the state where the cable 150 is located at the releasing position Pr, the linearly moving member 142 is separated from the cable end piece 144 in the direction D2 by the engagement of the male screw 141D and the female screw 142D and the rotation stop of the linearly moving member 142 by the rotation stop member 143 (fig. 8).

The controller 200 measures the time (rotation time) for rotating the motor 120 or the number of rotations of the output shaft 122 from the state in which the cable 150 is located at the braking position Pb, and stops the operation of the motor 120 at the position in the state shown in fig. 8 after the linear moving member 142 is separated from the cable end piece 144 in the direction D2. At this time, the rotation time or the number of rotations is set so that the stopped linear motion member 142 is spaced more reliably from other members (for example, the second gear 132 and the flange 141b of the rotating member 141) separated from the linear motion member 142 in the direction D2, in other words, so as not to contact or interfere with the other members.

Fig. 9 is a perspective view of the rotation stopper 143, fig. 10 is a perspective view of the linear motion member 142, and fig. 11 is a perspective view of the cable 150, the cable end 144, the rotation stopper 143, and the linear motion member 142 in a state where the cable 150 is located at the release position Pr.

As shown in fig. 9, the rotation preventing member 143 may be formed by press forming or bending a plate material of a metal material such as an iron-based material. The side wall 143a is formed in a hexagonal tubular shape. The six inner surfaces 143a1 of the side wall 143a are flat surfaces that extend in the axial direction and are orthogonal to the radial direction. An end face 143b1 of the projection 143b in the direction D1 is substantially orthogonal to the axial direction.

Further, the projection that projects in the axial direction from the end of the side wall 143a in the direction D1 is bent inward in the radial direction, thereby constituting the projection 143 b. The rotation stopper 143 has three protrusions 143b, but may have two protrusions 143b, or may have four or more protrusions 143 b.

As shown in fig. 10, the flange 142b provided on the linear motion member 142 has a hexagonal plate shape. The six outer surfaces 142b1 of the flange 142b are each planar surfaces that extend in the axial direction and are orthogonal to the radial direction. The six inner surfaces 143a1 of the rotation stop member 143 and the six outer surfaces 142b1 of the flange 142b face each other, whereby the linearly moving member 142 moves in the axial direction while being restricted from rotating about the third rotation center Ax 3. The linearly moving member 142 may be constituted by forging of a metal material such as an aluminum alloy, for example.

As shown in fig. 9 and 7, the flange 144b of the cable end piece 144 abuts against the end faces 143b1 of the three projections 143b, thereby positioning the cable 150 to the release position Pr. The cable end piece 144 can be more stably supported by the three protrusions 143 b.

As described above, in the present embodiment, the motion conversion mechanism 140 includes the rotating member 141 having the male screw 141d, and rotating about the third rotation center Ax3 (the axial center of the male screw 141 d) in conjunction with the output shaft 122, and the linear movement member 142 having the female screw 142d engaged with the male screw 141d and linearly moving with the rotation of the rotating member 141. The electric actuator 100 is attached to the back plate 6 in a state where the motion conversion mechanism 140 protrudes from the surface 6a of the back plate 6 opposite to the brake shoe 3 (brake member), and the rotating member 141 is rotationally driven by a third gear (ring gear) provided on the outer periphery of the rotating member 141 and rotating in conjunction with the output shaft 122.

According to such a configuration, for example, compared to a form in which a linearly moving member having a male screw moves linearly in accordance with rotation of a rotating member having a female screw as in patent document 1, there are advantages as follows: since the radial bearing 161 and the thrust bearing 162 supporting the rotary member 141 are easily reduced in diameter, the support structure of the rotary member 141 can be further miniaturized, and the radial bearing 161 and the thrust bearing 162 are further reduced in diameter, whereby the sliding speed of the radial bearing 161 and the thrust bearing 162 at the same rotation speed is further reduced, and thus the durability such as wear resistance is easily improved. Further, according to the above configuration, for example, compared to a form in which an output shaft of a motor or a member that rotates in conjunction with the output shaft is connected to an axial end surface of a rotating member of a motion conversion mechanism as in patent document 2, there is an advantage in that the overall length of the electric actuator 100 can be easily further shortened. Therefore, according to the above configuration, for example, in the brake device 2 in which the electric actuator 100 is attached to the back plate 6 in a state of protruding from the surface 6a of the back plate 6 opposite to the brake shoe 3, there are obtained an advantage that the vehicle-mounted space is easily secured by the downsizing of the electric actuator 100 as described above, and an advantage that the durability can be improved.

In the present embodiment, the male screw 141d and the female screw 142d are engaged with each other on the opposite side of the third gear 133 from the brake shoe 3, and the end 150a (one end) of the cable 150 (operating member) receives a force for operating the brake shoe 3 from the linearly moving member 142, and the other end of the cable 150 operates the brake shoe 3. According to such a configuration, for example, compared to a form in which the male screw and the female screw are engaged with each other on the stopper member side than the ring gear, the connection portion of the linearly moving member 142 to which the cable 150 is connected can be made further away from the stopper member, and therefore, the main body 112 can be made further shorter in the axial direction than in a case in which the connection portion of the linearly moving member 142 to which the cable 150 is connected is provided at a position closer to the stopper member. The main body 112 is a portion that receives a tensile force applied from the cable 150 in a braking state, and therefore, the rigidity is set relatively high. Therefore, the longer the axial length of the main body 112, the heavier the housing 110 and hence the electric actuator 100 are likely to be. Further, since the main body 112 is a mounting portion of the electric actuator 100, the longer the axial length of the main body 112, the further the center of gravity of the electric actuator 100 is from a mounted member (for example, a back plate), and thus vibration energy at the time of vibration of the electric actuator 100 is likely to become larger. In this regard, according to the above configuration, since the main body 112 can be made shorter, for example, the following advantages can be obtained: the electric actuator 100 can be made smaller or lighter, and the vibration energy when the electric actuator 100 vibrates can be further reduced.

In the present embodiment, for example, the cable 150 passes through the through hole 142c provided in the linearly moving member 142, and the end portion 150a (one end) on the opposite side of the brake shoe 3 with respect to the through hole 142c receives a force for operating the brake shoe 3 from the linearly moving member 142. According to this configuration, for example, compared to the configuration in which the operating member is disposed so as to bypass the outside in the radial direction of the ring gear, the cable 150 can be disposed in a linearly extending state in the vicinity of the third rotation center Ax3 (the axial center of the rotating member 141), and therefore, the reaction force related to the operation of the brake shoe 3 can be suppressed from acting in the direction intersecting the third rotation center Ax 3. Therefore, for example, a force that causes the rotating member 141 to tilt can be suppressed, which contributes to downsizing of the support structure of the rotating member 141 and improvement of durability. Further, for example, as compared with a configuration in which the operating member is disposed so as to bypass the outside in the radial direction of the ring gear, the electric actuator 100 can be prevented from being increased in size in the radial direction.

In the present embodiment, the cable end 144 (transmission member) fixed to the cable 150 is configured to be axially separable from the linearly moving member 142. According to this structure, the linear movement member 142 can be moved independently of the cable 150. In a more specific example, the over run of the linearly moving member 142 can be allowed without moving the cable 150 and the brake shoe 3. Therefore, the control accuracy in controlling the amount of movement of the linearly moving member 142 can be relaxed.

In the present embodiment, the protrusion 143b of the rotation stopper 143 (movement restricting member) restricts the movement of the cable end piece 144 in the direction D2. According to such a structure, for example, in addition to transmitting force between the cable 150 and the linearly moving member 142, the cable end piece 144 can be utilized in the movement restriction of the cable 150. Therefore, for example, since the rotation of the rotating member 141 is prevented from being transmitted to the cable end 144 due to the cable end 144 abutting against the rotating member 141, it is possible to prevent a problem such as abrasion due to sliding between the rotating member 141 and the cable end 144.

In the present embodiment, the control device 200 controls the motor 120 as follows: after the movement of the cable terminal 144 in the direction D2 (releasing direction) is restricted by the rotation restricting member 143 (movement restricting member), the rotation is stopped. With this configuration, for example, the motor 120 can be operated or stopped in a state where the cable 150 reaches the release position Pr more reliably in accordance with the driving time or the rotation amount (the number of rotations, the rotation angle) of the motor 120 required for moving the cable 150 from the braking position Pb to the release position Pr. Thus, for example, the following advantages are obtained: it is not necessary to provide a sensor or the like for detecting the positions of the cable 150 and the linear motion member 142 in order to stop the operation of the motor 120.

In the present embodiment, the rotation stopper 143 has an inner surface 143a1 (guide portion) that guides the linear motion member 142 in the axial direction while restricting the rotation of the linear motion member 142. According to such a structure, for example, the electric actuator 100 can be realized as a simpler structure than a structure in which the rotation stop member 143 and the movement restricting member are separately provided.

In the present embodiment, the rotating member 141 is provided with the male screw 141d, and the linearly moving member 142 is provided with the female screw 142 d. According to such a configuration, the motion conversion mechanism 140 and the electric actuator 100 can be realized with a relatively simple configuration by the rotating member 141 having the male screw 141d and the linearly moving member 142 having the female screw 142d, for example.

In the present embodiment, in a state where the cable 150 is located at the release position Pr, a gap is provided in the axial direction between the rotating member 141 and the cable end 144. According to such a structure, for example, the rotation of the rotating member 141 can be suppressed from being transmitted to the cable 150 via the cable tip 144. Further, the same effect can be obtained also when a rotation stopping structure that regulates relative rotation in the circumferential direction by a relationship of irregularities or the like is provided between the cable end piece 144 and the rotation stopping member 143.

In the present embodiment, the rotation stopper 143 may be formed by press forming or bending of a metal material. With this structure, the rotation stopper 143 can be configured relatively easily or inexpensively, for example.

[ first modification ] A method for manufacturing a semiconductor device

Fig. 12 is a sectional view of a part of an electric actuator 100A according to the present modification. The structure shown in fig. 12 can be replaced to the correspondence of the electric actuator 100 of the above-described embodiment. In the motion conversion mechanism 140A of the present modification, the guide mechanism 145 is provided between the cable end 144A and the rotation stopping member 143A, and between the cable end 144A and the linear movement member 142A, and the guide mechanism 145 is positioned in the radial direction such that the centers of the cable end 144A and the cable 150 are positioned at the third rotation center Ax 3. The guide mechanism 145 includes an outer surface 144c1 of a protrusion 144c protruding from the flange 144b of the cable terminal 144A in the direction D2, an inner surface 143b2 (concave portion, opening portion) of the protrusion 143b of the rotation stopper 143A, and an inner surface 142c1 of the linear moving member 142A provided at the distal end on the side of the direction D1. The outer surface 144c1 is a conical outer surface with a decreasing diameter proceeding in the direction D2, and the inner surfaces 143b2 and 142c1 are conical inner surfaces with a decreasing diameter proceeding in the direction D2. The outer surface 144c1 and the inner surface 143b2 are configured to have a slight gap between the outer surface 144c1 and the inner surface 143b2 in a state where the flange 144b abuts the end surface 143b1 of the projection 143 b. The outer surface 144c1 and the inner surface 142c1 are configured to have a slight gap between the outer surface 144c1 and the inner surface 142c1 in a state where the flange 144b abuts against the distal end of the linearly-moving member 142A on the direction D1 side. With this configuration, for example, the tension of the cable 150 due to the inclination or displacement of the cable 150 can be prevented from being unevenly applied to the rotation stopper 143A or the linear motion member 142A. Further, a protrusion (outer surface) may be provided on the rotation stopper and the linear motion member, and a recess (opening, inner surface) may be provided on the transmission member. As described above, the guide mechanism 145 does not need to include both the rotation stopper 143A and the linear movement member 142A, and may include one of the rotation stopper 143A and the linear movement member 142A, for example.

[ second modification ] A method for producing a semiconductor device

Fig. 13 is a sectional view of a part of an electric actuator 100B according to the present modification. The structure shown in fig. 13 can be replaced to the correspondence of the electric actuator 100 of the above-described embodiment. In the present modification, the motion conversion mechanism 140B includes a linear movement member 142B integrated with a cable end 144B. Further, a disc spring 146 is provided as a compression spring that generates a reaction force in the axial direction between the flange 144B of the cable end piece 144B and the rotation stopper 143. In this case, as the cable 150 approaches the release position Pr, the reaction force in the axial direction of the disc spring 146 increases, and the torque of the motor 120 increases accordingly. Therefore, the control device 200 can detect that the cable 150 has reached the release position Pr by, for example, the drive current of the motor 120 exceeding a threshold value, and stop the supply of the drive current to the motor 120 at that point in time.

[ third modification ] of the invention

Fig. 14 is a perspective view of a part of an electric actuator 100C according to the present modification. The structure shown in fig. 14 can be replaced to the corresponding position of the electric actuator 100 of the above embodiment. In the present modification, the protrusion 143b of the rotation stopper 143C functions as a leaf spring (compression spring) that generates a reaction force in the axial direction. In this case, the projection 143b is elastically deformed so that the bending of the projection 143b becomes larger as the cable 150 approaches the release position Pr, whereby the axial reaction force of the projection 143b increases and the torque of the motor 120 increases. Therefore, in the present modification, for example, the control device 200 can detect that the cable 150 has reached the release position Pr by the drive current of the motor 120 exceeding the threshold value, and stop the supply of the drive current to the motor 120 at that point in time. The reaction force (elastic force, biasing force) and the spring constant can be adjusted by the specification (number, shape, size, thickness, numerical value, etc.) of the projection 143 b. In the example of fig. 14, the thickness of the top end portion of the projection 143b is formed thinner than the thickness of the root portion, for example.

The compression spring (urging member, elastic member) that generates a reaction force in the axial direction in accordance with the movement of the cable 150 is not limited to the leaf spring and the leaf spring, and may be, for example, a coil spring, an elastic body, or the like. The compression spring may be interposed between the flange 142b of the linear motion member 142 and the flange 141b of the rotation member 141, between the flange 142b of the linear motion member 142 and the main body 112, or the like. Further, various compression springs exemplified in the present specification may be provided in the electric actuator 100 in which the cable end 144 and the linear moving member 142 are axially separable as in the above-described embodiments. In this case, by compressing the spring, for example, sticking due to engagement of the external thread 141d with the internal thread 142d can be suppressed.

The embodiments of the present invention have been described above, but the embodiments are examples and are not intended to limit the scope of the invention. The above embodiments can be implemented in other various forms, and various omissions, substitutions, combinations, and alterations can be made without departing from the spirit of the invention. The specification (structure, type, direction, shape, size, length, width, thickness, height, number, arrangement, position, material, etc.) of each structure, shape, etc. can be appropriately changed.

For example, the operating member is not limited to a pulling member such as a cable, and may be a pressing member such as a rod.

For example, the operating member may not penetrate the through hole of the rotating member. In this case, the operating member may be arranged to pass around the outside of the ring gear in the radial direction. The rotating member may not be provided with a through hole. The male screw and the female screw may be engaged with each other on the brake member side of the ring gear.

Claims

1. A brake device is provided with: a braking member that is pressed against a drum rotor that rotates integrally with a wheel, thereby braking the drum rotor; a back plate supporting the braking member; and an electric actuator provided to the back plate and operating the brake member;

wherein the electric actuator has:

a motor having an output shaft that rotates;

a motion conversion mechanism including a rotary member having a male screw and rotating around an axis of the male screw in conjunction with the output shaft, and a linear movement member having a female screw engaged with the male screw and linearly moving in accordance with rotation of the rotary member; and

an actuating member that receives a force for actuating the braking member from the linear moving member;

the electric actuator is attached to the back plate in a state where the motion conversion mechanism protrudes from a surface of the back plate opposite to the brake member;

the rotating member is rotationally driven by a ring gear provided on an outer periphery of the rotating member and rotating in conjunction with the output shaft.

2. The braking device according to claim 1,

the male screw and the female screw are engaged with each other on the opposite side of the ring gear from the brake member;

one end of the operating member receives a force for operating the braking member from the linear motion member, and the other end of the operating member operates the braking member.

3. The braking device according to claim 2,

the rotating member is provided with a through hole along the axis,

the operating member is passed through the through hole,

the one end is located on the opposite side of the through hole from the braking member.

4. The braking device according to any one of claims 1 to 3,

the brake device is provided with a transmission member that is fixed to the operating member, is configured to be separable from the linear motion member in the axial direction of the shaft center, and is configured to transmit a force for operating the brake member from the linear motion member to the operating member.

5. The braking device according to claim 4,

the brake device is provided with a movement limiting member that limits movement of the transmission member in a release direction in which braking by the brake member is released.

6. The braking device according to claim 5,

a control unit for controlling the motor is provided,

the control unit controls the motor such that, when the motor is operated to move the operating member from the braking position in the braking state to the release direction, the motor is operated: the rotation is stopped after the movement of the transmission member in the release direction is restricted by the movement restricting member.

7. The braking device according to claim 5 or 6,

the movement restricting member has a guide portion that guides the linear movement member in an axial direction of the shaft center while restricting rotation of the linear movement member.