JP2017082834A - Brake for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a brake for a vehicle capable of further reducing rotational load of a motor.SOLUTION: A brake for a vehicle has: for example, an operation member for moving a brake member to brake a wheel; a motor; a rotary member rotated by the motor; a linear motion member linearly moved accompanying rotation of the rotary member to move the operation member; an elastic member; an opposite member for elastically deforming the elastic member in an axial direction to the rotary member by movement in the axial direction of the rotary member, of the rotary member; and a slide member disposed between the rotary member and the opposite member, and making the rotary member slide to the opposite member in rotating the rotary member.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a vehicle brake.

  2. Description of the Related Art Conventionally, a vehicular brake that obtains a braking state by converting the rotation of a motor into a linear motion of a cable in a motion conversion mechanism and pulling the cable to move a brake shoe is known (for example, Patent Document 1). In patent document 1, it is comprised so that the rotational load of a motor may increase by compression of the disc spring by the movable member of a motion conversion mechanism, for example. In this case, by detecting the rotational load of the motor, for example, it can be detected that the linear motion member or the cable is at a predetermined position, for example, the boundary position of the movable range.

Special table 2014-504711 gazette

  In such a vehicular brake, for example, if the frictional resistance torque between the two parts that rotate relative to each other while sliding with the compression of the disc spring becomes too large, the rotational load when the motor is subsequently moved increases. There was a possibility that it was too much. Then, one of the subjects of this invention is obtaining the brake for vehicles which can reduce the rotational load of a motor more, for example.

  The vehicle brake according to the present invention includes, for example, an operation member that moves a braking member to brake a wheel, a motor, a rotation member that is rotated by the motor, and a linear motion that accompanies the rotation of the rotation member. A linear member that moves the member, an elastic member, an opposing member that elastically deforms the elastic member in the axial direction between the rotating member and the rotating member by moving the rotating member in the axial direction; A sliding member that is provided between the rotating member and the opposing member and that slides the rotating member relative to the opposing member when the rotating member is rotated.

  In the vehicle brake, a sliding member provided between the rotating member and one of the elastic member and the opposing member slides the rotating member relative to one when the rotating member is rotated. Therefore, for example, the frictional resistance torque associated with the relative rotation and sliding between the rotating member and one of the elastic member and the opposing member can be further reduced. Therefore, the rotational load of the motor can be further reduced.

  Further, in the vehicle brake, for example, the sliding member has a convex curved contact area at a central portion as viewed from the axial direction.

  In the vehicle brake, the contact region can be disposed in the vicinity of the rotation shaft of the rotating member. Therefore, the moment arm in the frictional resistance torque associated with the relative rotation between the rotating member and one of the elastic member and the opposing member can be reduced, whereby the relative rotation between the rotating member and one of the elastic member and the opposing member can be reduced. In addition, the frictional resistance torque accompanying the sliding can be further reduced. Therefore, the rotational load of the motor can be further reduced.

  In the vehicle brake, for example, the sliding member is a sphere.

  According to the above vehicle brake, by using a sphere as the sliding member, the frictional resistance torque associated with the relative rotation and sliding between the rotating member, one of the elastic member and the opposing member can be reduced with a relatively simple configuration. It is possible to reduce the rotational load of the motor.

  In the vehicle brake, for example, the sliding member is a rolling bearing.

  According to the above-described vehicle brake, by using a rolling bearing as the sliding member, the frictional resistance torque associated with the relative rotation between the rotating member, the elastic member, and one of the opposing members can be further reduced with a relatively simple configuration. As a result, the rotational load of the motor can be reduced.

FIG. 1 is an exemplary and schematic rear view of a vehicle brake according to an embodiment from the rear of the vehicle. FIG. 2 is an exemplary schematic side view of the vehicle brake according to the embodiment from the outside in the vehicle width direction. FIG. 3 is an exemplary schematic side view of the operation of the braking member by the vehicle brake moving mechanism of the embodiment, and is a diagram in a non-braking state. FIG. 4 is an exemplary and schematic side view of the operation of the braking member by the vehicle brake moving mechanism of the embodiment, and is a diagram in a braking state. FIG. 5 is an exemplary and schematic cross-sectional view of the drive mechanism included in the vehicle brake of the first embodiment, and is a view in a non-braking state. FIG. 6 is an exemplary schematic sectional view of a drive mechanism included in the vehicle brake according to the first embodiment, and is a diagram in a braking state. 7 is a sectional view taken along line VII-VII in FIG. FIG. 8 is an exemplary schematic sectional view of a drive mechanism included in the vehicle brake of the second embodiment. FIG. 9 is an exemplary and schematic cross-sectional view of a drive mechanism included in the vehicle brake of the third embodiment. FIG. 10 is an exemplary and schematic cross-sectional view of a drive mechanism included in a vehicle brake according to a modification of the first embodiment.

  Hereinafter, exemplary embodiments of the present invention are disclosed. The configuration of the embodiment shown below, and the operation and result (effect) brought about by the configuration are examples. The present invention can be realized by configurations other than those disclosed in the following embodiments. According to the present invention, it is possible to obtain at least one of various effects (including derivative effects) obtained by the configuration.

  The following embodiments and modifications include similar components. Therefore, in the following, the same reference numerals are given to the same components, and redundant description may be omitted. Moreover, in this specification, the ordinal number is given for convenience in order to distinguish parts, parts, and the like, and does not indicate priority or order.

  1 to 4, for the sake of convenience, the front in the vehicle front-rear direction is indicated by an arrow X, the outer side in the vehicle width direction (axle direction) is indicated by an arrow Y, and the upper side in the vehicle vertical direction is indicated by an arrow Z. .

  In the following, a case where the brake device 2 which is an example of a vehicle brake is applied to the left rear wheel (non-drive wheel) will be exemplified, but the present invention can be similarly applied to other wheels. It is.

<First Embodiment>
<Brake device configuration>
As shown in FIG. 1, the brake device 2 is accommodated inside the peripheral wall 1 a of the cylindrical wheel 1. The brake device 2 is configured as a drum brake. That is, as shown in FIG. 2, the brake device 2 includes arc-shaped brake shoes 3 on both the front and rear sides. A cylindrical drum 4 (see FIGS. 3 and 4) is provided around the brake device 2. The drum 4 rotates integrally with the wheel 1 around the rotation center Ax along the vehicle width direction (Y direction). The brake device 2 moves the two brake shoes 3 so as to contact the inner peripheral surface 4 a of the cylindrical drum 4. Thereby, the drum 4 and the wheel 1 are braked by the friction between the brake shoe 3 and the drum 4. The brake shoe 3 is an example of a braking member.

  The brake device 2 includes a wheel cylinder 51 (see FIG. 2) that operates by hydraulic pressure and a motor 120 (see FIG. 5) that operates by energization as actuators that move the brake shoe 3. Each of the wheel cylinder 51 and the motor 120 can move the two 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. The motor 120 may also be used for braking during traveling.

  As shown in FIGS. 1 and 2, the brake device 2 includes a disk-shaped back plate 6. The back plate 6 is provided in a posture intersecting with the vehicle width direction. That is, the back plate 6 extends substantially along a direction intersecting the vehicle width direction, specifically, substantially along a direction (XZ plane) orthogonal to the vehicle width direction. 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 plate 6 in the vehicle width direction. The back plate 6 supports each component of the brake device 2 directly or indirectly. That is, the back plate 6 is an example of a support member. The back plate 6 is connected to a connection member (not shown) with the vehicle body. The connection member is, for example, a part of the suspension (for example, an arm, a link, an attachment member, etc.). The opening 6b provided in the back plate 6 shown in FIG. 2 is used for coupling with the connection member. The brake device 2 can also be used for drive wheels. When the brake device 2 is used for driving wheels, an axle shaft (not shown) passes through an opening 6c provided in the back plate 6 shown in FIG. The back plate 6 is made of, for example, a metal material.

  The wheel cylinder 51 and the brake shoe 3 shown in FIG. 2 are arranged on the outer side of the back plate 6 in the vehicle width direction. The brake shoe 3 is movably supported on the back plate 6. In the present embodiment, as shown in FIG. 3, for example, the lower end 3a of the brake shoe 3 is supported by the back plate 6 so as to be rotatable around the rotation center C1. The rotation center C1 is substantially parallel to the rotation center C of the wheel 1. The wheel cylinder 51 is supported on the upper end portion of the back plate 6. The wheel cylinder 51 has two movable parts (pistons) (not shown) that can project in the vehicle front-rear direction (left-right direction in FIG. 2). The wheel cylinder 51 causes the two movable parts to protrude in response to the pressurization. The two projecting movable parts push the upper end 3b of the brake shoe 3, respectively. Due to the protrusion of the two movable parts, the two brake shoes 3 rotate around the rotation center C1 and move so that the upper end parts 3b are separated from each other in the vehicle front-rear direction. As a result, the two brake shoes 3 move outward in the radial direction of the rotation center C of the wheel 1. A belt-like lining 31 along the cylindrical surface is provided on the outer periphery of each brake shoe 3. Therefore, the lining 31 and the inner peripheral surface 4a (see FIG. 4) of the drum 4 come into contact with each other by the movement of the two brake shoes 3 to the radially outer side of the rotation center C. Due to the friction between the lining 31 and the inner peripheral surface 4a, the drum 4 and thus the wheel 1 are braked. As shown in FIG. 2, the brake device 2 includes a return member 32. When the operation of pushing the brake shoe 3 by the wheel cylinder 51 is released, the return member 32 moves from the position where the two brake shoes 3 come into contact with the inner peripheral surface 4a of the drum 4 (braking position Pb, see FIG. 4). The drum 4 is moved to a position (non-braking position Pn, initial position, see FIG. 3) that does not contact the inner peripheral surface 4a of the drum 4. The return member 32 is an elastic member such as a coil spring, for example, and gives each brake shoe 3 a force in a direction approaching the other brake shoe 3, that is, a force in a direction away from the inner peripheral surface 4 a of the drum 4. .

<Configuration and operation of moving mechanism>
Further, the brake device 2 includes a moving mechanism 8 (see FIGS. 3 and 4) that moves the two brake shoes 3 from the non-braking position Pn to the braking position Pb. The moving mechanism 8 is provided outside the back plate 6 in the vehicle width direction. As shown in FIGS. 2 to 4, the moving mechanism 8 includes a lever 81 (not shown in FIG. 2), a cable 82, and a strut 83. The lever 81 is one of the two, for example, between the brake shoe 3L on the left side in FIG. 2 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 Ax of the wheel 1. Is provided. The lever 81 is supported by the brake shoe 3L so as to be rotatable about the rotation center Ax2. The rotation center Ax2 is located on the side of the brake shoe 3L away from the rotation center Ax0, that is, the upper end in FIG. 2, and is substantially parallel to the rotation center Ax and the rotation center Ax0. The cable 82 moves the lower end portion 81a far from the rotation center Ax2 of the lever 81, for example, in a direction approaching the brake shoe 3R on the right side in FIG. The cable 82 moves substantially along the back plate 6. The strut 83 is interposed between the lever 81 and the brake shoe 3R different from the brake shoe 3L on which the lever 81 is supported, and stretches between the lever 81 and the other brake shoe 3R. The connection position P1 between the lever 81 and the strut 83 is set between the rotation center Ax2 and the connection position P2 between the cable 82 and the lever 81. The cable 82 is an example of an operating member that moves the brake shoe 3.

  In such a moving mechanism 8, when the cable 82 is pulled and moved to the right side in FIGS. 3 and 4, the lever 81 moves in a direction approaching the brake shoe 3 </ b> R as shown in FIG. 4 (arrow a). The lever 81 pushes the brake shoe 3R through the strut 83 (arrow b). As a result, the brake shoe 3R rotates around the rotation center Ax0 from the non-braking position Pn (FIG. 3) (arrow c) and moves to a position (braking position Pb, FIG. 4) in contact with the inner peripheral surface 4a of the drum 4. . In this state, the connection position P2 between the cable 82 and the lever 81 corresponds to the power point, the rotation center Ax2 corresponds to the fulcrum, and the connection position P1 between the lever 81 and the strut 83 corresponds to the action point. Further, when the brake shoe 3R is in contact with the inner peripheral surface 4a and the lever 81 moves to the right side in FIGS. 3 and 4, that is, the strut 83 pushes the brake shoe 3R (arrow a), the strut 83 is stretched. As a result, the lever 81 rotates in the direction opposite to the direction in which the lever 81 moves, that is, counterclockwise in FIGS. 3 and 4 with the connection position P1 with the strut 83 as a fulcrum (arrow d). As a result, the brake shoe 3L rotates around the rotation center Ax0 from the non-braking position Pn (FIG. 3) and moves to a position (braking position Pb, FIG. 4) in contact with the inner peripheral surface 4a of the drum 4. In this manner, the brake shoes 3L and 3R are moved from the non-braking position Pn to the braking position Pb by the operation of the moving mechanism 8. In the state after the brake shoe 3R contacts the inner peripheral surface 4a of the drum 4, the connection position P1 between the lever 81 and the strut 83 serves as a fulcrum. The amount of movement of the brake shoes 3L, 3R is very small, for example, 1 mm or less.

<Drive mechanism>
The drive mechanism 100 shown in FIGS. 1, 2, 5 and 6 moves the two brake shoes 3 from the non-braking position Pn to the braking position Pb via the moving mechanism 8 described above. The drive mechanism 100 is located on the inner side in the vehicle width direction of the back plate 6 and is fixed to the back plate 6. The cable 82 shown in FIGS. 2 to 4 passes through an opening (not shown) provided in the back plate 6.

  As shown in FIG. 5, the drive mechanism 100 includes a housing 110, a motor 120, a speed reduction mechanism 130, and a motion conversion mechanism 140.

  The housing 110 supports the motor 120, the speed reduction mechanism 130, and the motion conversion mechanism 140. The housing 110 includes a plurality of members. The plurality of members are coupled and integrated by a coupling tool (not shown) such as a screw. A housing chamber R surrounded by a wall 111 is provided in the housing 110. The motor 120, the speed reduction mechanism 130, and the motion conversion mechanism 140 are accommodated in the accommodation chamber R and covered with the wall portion 111. The housing 110 may be referred to as a base, a support member, a casing, or the like. In addition, the structure of the housing 110 is not limited to what was illustrated here.

  The motor 120 is an example of an actuator, and includes a case 121 and a housing component housed in the case 121. The housing components include, for example, a stator, a rotor, a coil, and a magnet (not shown) in addition to the shaft 122. The shaft 122 protrudes from the case 121 in the direction D1 along the first rotation center Ax1 of the motor 120. The direction D1 is the right side in FIG. The motor 120 is driven by driving power based on the control signal, and rotates the shaft 122. The shaft 122 can also be referred to as an output shaft.

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

  The first gear 131 rotates integrally with the shaft 122 of the motor 120. The first gear 131 can be referred to as a drive gear.

  The second gear 132 rotates around a second rotation center Ax2 parallel to the first rotation center Ax1. 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 lower rotational speed than the first gear 131. The output gear 132b is located in the direction opposite to the D1 direction with respect to the input gear 132a. The second gear 132 can be referred to as an idler gear.

  The third gear 133 rotates around a third rotation center Ax3 that is parallel to the first rotation center Ax1. The third gear 133 meshes with the output gear 132b of the second gear 132. The number of teeth of the third gear 133 is larger than the number of teeth of the output gear 132b. Therefore, the third gear 133 is decelerated to a lower rotational speed than the second gear 132. The third gear 133 can be referred to as a driven gear. Note that the configuration of the speed reduction mechanism 130 is not limited to that 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 motion member 142.

  The rotating member 141 rotates around the third rotation center Ax3. The rotating member 141 has a small diameter portion 141a and a large diameter portion 141b having a larger outer diameter than the small diameter portion 141a. The small diameter portion 141a is a portion located in the direction opposite to the D1 direction in the rotating member 141, and is configured in a cylindrical shape. The large diameter portion 141b is a portion of the rotating member 141 that is positioned in the D1 direction. The large diameter portion 141b has a bottom wall portion 141b1 and a side wall portion 141b2. The bottom wall portion 141b1 projects in the radial direction from the end portion of the small diameter portion 141a in the D1 direction, and is configured in an annular shape and a plate shape. The side wall 141b2 extends in the direction D1 from the peripheral edge of the bottom wall 141b1, and is configured in a cylindrical shape. The side wall part 141b2 may be referred to as a peripheral wall part or a cylindrical wall part. The large-diameter portion 141b is provided with a concave portion 141b3 that is open toward the D1 direction.

  The teeth of the third gear 133 are provided on the side wall portion 141b2 of the large diameter portion 141b. That is, the rotating member 141 is also the third gear 133. The part where the teeth of the third gear 133 are provided is an example of a driven part. The cylindrical portion 112 of the housing 110 is accommodated in the recess 141b3. In the concave portion 141b3, the thrust bearing 143 is positioned between the end portion 112a of the cylindrical portion 112 in the direction opposite to the D1 direction and the bottom wall portion 141b1. The thrust bearing 143 receives a load in the axial direction of the third rotation center Ax3. The thrust bearing 143 is a thrust roller bearing in the example of FIG. 5, but is not limited to this. The large-diameter portion 141b and the rotating member 141 are rotatably supported by the housing 110 via a thrust bearing 143.

  The small diameter portion 141 a is inserted into a radial bearing 144 housed in the first hole 113 a of the housing 110. The cross section of the first hole 113a is substantially circular. The first hole 113a extends along the axial direction of the third rotation center Ax3. The small-diameter portion 141a and thus the rotating member 141 are rotatably supported by the housing 110 via a radial bearing 144. Although the radial bearing 144 is a metal bush in the example of FIG. 5, it is not limited to this.

  The rotating member 141 is provided with a through hole 141c having a circular cross section that penetrates the small diameter portion 141a and the bottom wall portion 141b1. A female screw part 145a is provided in the through hole 141c.

  The linear motion member 142 extends along the third rotational center Ax3 and penetrates the rotational member 141. The linear motion member 142 includes a rod-like portion 142a and a connecting portion 142b.

  The rod-shaped portion 142 a is inserted into the through hole 141 c of the rotating member 141, the concave portion 141 b 3 of the large-diameter portion 141 b of the rotating member 141, and the second hole 113 b provided in the cylindrical portion 112 of the housing 110. The cross section of the second hole 113b is substantially circular. The second hole 113b is positioned in the direction D1 of the first hole 113a and extends along the axial direction of the third rotation center Ax3. The rod-like portion 142a has a substantially circular cross section. The rod-like portion 142 a is provided with a male screw portion 145 b that meshes with the female screw portion 145 a of the rotating member 141.

  The connecting portion 142 b is connected to the end portion 82 a of the cable 82 by the connecting member 146. As shown in FIG. 7, the connecting member 146 passes through the end portion 82 a and the connecting portion 142 b of the cable 82. The connecting member 146 is, for example, a pin.

  As shown in FIG. 7, a groove 113 c is provided on the inner surface of the second hole 113 b provided in the cylindrical portion 112 of the housing 110. The groove 113c extends with a substantially constant width and depth along the third rotation center Ax3. The groove 113c is provided at two locations across the third rotation center Ax3. The end of the connecting member 146 in the longitudinal direction is inserted into the groove 113c. The circumferential width of the third rotation center Ax3 of the groove 113c is set to be slightly larger than the width of the end portion of the connecting member 146 in the longitudinal direction. Therefore, the connection member 146 and the circumferential surface of the groove 113c are in contact with each other, so that the rotation of the connection member 146 and thus the linear motion member 142 around the third rotation center Ax3 is limited. Further, as shown in FIG. 6, the connecting member 146 is movable in the recess 141b3. That is, the connecting member 146 is positioned in the recess 141b3 in a state where the linear motion member 142 is positioned at the braking position Pb. Further, the surface 113d in the direction D1 of the groove 113c shown in FIG. 7 restricts the connection member 146 from moving in the direction D1. The surface 113d can be referred to as a stopper or a position limiter. In addition, the structure which couple | bonds the linear motion member 142 and the cable 82 is not limited to the example of FIG.

  In such a configuration, the rotation of the shaft 122 of the motor 120 is transmitted to the rotating member 141 via the speed reduction mechanism 130, and when the rotating member 141 rotates, the female screw portion 145 a of the rotating member 141 and the male screw portion of the linear motion member 142. Due to the meshing with 145b and the restriction of the rotation of the linear motion member 142 by the housing 110 in the groove 113c, the linear motion member 142 and the non-braking position Pn (FIG. 5) and the braking along the axial direction of the third rotational center Ax3 It moves between the position Pb (FIG. 6).

  The portion of the cylindrical portion 112 of the housing 110 where the groove 113c is provided is an example of a rotation limiting portion that limits the rotation of the connecting member 146 and thus the linear motion member 142 around the third rotation center Ax3. As a result, the linear motion member 142 is also an example of a guide portion that guides the linear motion member 142 along the axial direction of the third rotation center Ax3.

<Motor rotational load increasing mechanism and frictional resistance torque reducing mechanism>
As shown in FIG. 5, a sphere 160, a plate is interposed between the wall 111 a of the housing 110 positioned in the direction opposite to the D <b> 1 direction of the rotating member 141 (left direction in FIG. 5) and the rotating member 141. A spring 151 and a spacer 152 are provided. The sphere 160, the leaf spring 151, and the spacer 152 are arranged in the axial direction of the third rotation center Ax3.

  The sphere 160 is in contact with the wall portion 111a of the housing 110, and is positioned at the end of the first hole 113a opposite to the D1 direction. The sphere 160 is, for example, a steel ball. The sphere 160 has a convex curved surface, that is, a spherical surface in this example, in the central portion of the third rotation center Ax3 as viewed from the axial direction. The contact region 160a is a part of the sphere 160 that contacts an adjacent member, that is, the wall portion 111a or the leaf spring 151 of the housing 110 in the example of FIG. The sliding member having the contact region 160a may be a member other than the sphere 160, such as a hemisphere or a blunt cone.

  The leaf spring 151 is positioned in the D1 direction (right direction in FIG. 5) of the ball 160. The leaf spring 151 is located between the ball 160 and the spacer 152. The leaf spring 151 includes a plurality of annular, plate-like, and flat conical elements. The leaf spring 151 can be made of, for example, stainless steel. When the leaf spring 151 is compressed in the axial direction of the third rotation center Ax3, a reaction force is generated that elastically extends in the axial direction. The leaf spring 151 is an example of an elastic member. The leaf spring 151 can be referred to as a biasing member or a repulsion member. The elastic member may be an elastic member other than a leaf spring, such as a coil spring or an elastomer.

  The spacer 152 is located in the direction D1 of the leaf spring 151. The spacer 152 is located between the leaf spring 151 and the small diameter portion 141 a of the rotating member 141. The spacer 152 is configured in a cylindrical shape.

  When the linear motion member 142 moves in the direction D1 due to the rotation of the motor 120, the movement of the linear motion member 142 in the direction D1 is limited by, for example, contact between the connecting member 146 and the surface 113d illustrated in FIG. Then, the rotating member 141 is in a state in which the movement (linear motion) of the linear motion member 142 in the direction D1 is restricted despite the fact that the rotational member 141 attempts to rotate by the rotational drive of the motor 120. For this reason, the rotating member 141 generates a reaction force in the direction opposite to the direction D1 (the left direction in FIG. 5) from the linear moving member 142 due to the engagement between the female screw portion 145a of the rotating member 141 and the male screw portion 145b of the linear moving member 142. receive. In this case, in this embodiment, the leaf spring 151 is sandwiched between the wall portion 111a of the housing 110, the ball 160, and the rotating member 141, and is elastically compressed. The increase in the elastic compression reaction force of the leaf spring 151 increases the force in the normal direction of the thread surface at the female screw portion 145a and the male screw portion 145b, so that the frictional resistance torque between the female screw portion 145a and the male screw portion 145b increases. As a result, the load torque of the motor 120 increases. Therefore, for example, the control device (not shown) of the motor 120 detects that the movement of the linear motion member 142 in the direction D1 is limited by detecting the load torque based on the drive current of the motor 120 or the like. can do. That is, in the present embodiment, a motor rotation load increasing mechanism is constituted mainly by a leaf spring 151 as an elastic member that gives an elastic reaction force to the rotating member 141 in the axial direction.

  In such a configuration, the sphere 160 reduces frictional resistance torque (sliding resistance torque) between one or both of the sphere 160 and the wall portion 111 a and between the leaf spring 151 and the sphere 160. be able to. This is because, as described above, the sphere 160 has a convex curved surface at the center, that is, a spherical contact region 160a, as seen from the axial direction of the third rotation center Ax3. Since the moment arm from the third rotation center Ax3 to the contact area 160a is relatively small (short), the frictional force and the moment between the wall 160a and the ball 160 and between the leaf spring 151 and the ball 160 are relatively small. The frictional resistance torque that is multiplication with the arm is relatively small. If the ball 160 is not provided, the end of the leaf spring 151 in the direction D1 tends to be rotated by the frictional resistance with the rotating member 141 rotated by the motor 120, while the end of the leaf spring 151 is opposite to the direction D1. The end of the direction tends to be hindered by the frictional resistance with the fixed wall 111a. Therefore, the wall portion 111a, the leaf spring 151, the spacer 152, and the rotating member 141 may increase the frictional resistance torque on their contact surfaces. In this case, while the leaf spring 151 is elastically compressed, a state where the frictional resistance torque is relatively high, that is, a state where the rotational load of the motor 120 is relatively high is maintained. In this regard, in the present embodiment, the ball 160 can provide a portion (section) with a small frictional resistance torque between the wall 111a and the rotating member 141, and therefore, between the wall 111a and the rotating member 141. An increase in the rotational load of the motor 120 based on the frictional resistance torque (sliding torque) between the two components can be suppressed. That is, in this embodiment, a frictional resistance torque reduction mechanism is mainly configured by the sphere 160. The sphere 160 is an example of a sliding member that slides the rotating member 141 with respect to the wall portion 111a of the housing 110 when the rotating member 141 is rotated. The wall 111a is an example of a facing member. In the present embodiment, in a state where the leaf spring 151 is elastically compressed, the rotating member 141, the spacer 152, and the leaf spring 151 can rotate substantially integrally. The wall 111a can be referred to as a fixed member, a non-rotating member, or a relative rotating member.

  Even when the ball 160, that is, the sliding member or the frictional resistance torque reduction mechanism is provided as in the present embodiment, the elastic compression reaction force in the axial direction of the leaf spring 151 is the same as that of the female screw portion 145a. Since it acts on the meshing part with the male screw part 145b, there is no problem in the control using the detection of the increase in the load torque of the motor 120 due to the increase of the frictional force in the meshing part.

  As described above, in the present embodiment, the ball 160 is provided between the rotating member 141 and the wall 111a (opposing member), and when the rotating member 141 is rotated, the rotating member 141 is moved to the wall 111a. Slide against. Therefore, according to this embodiment, for example, an event in which the frictional resistance torque between the rotating member 141 and the wall 111a increases and the rotational load of the motor 120 increases is unlikely to occur.

  In the present embodiment, the sphere 160 has a convex curved contact area 160a at the center of the third rotational center Ax3 as viewed from the axial direction. Therefore, according to the present embodiment, for example, the moment arm in the frictional resistance torque between the ball 160 and the wall 111a or the leaf spring 151 associated with the rotation of the rotating member 141 can be reduced, thereby reducing the frictional resistance torque. can do. Therefore, the rotational load of the motor 120 can be further reduced.

  In the present embodiment, the friction resistance torque reduction mechanism can be configured with a relatively simple configuration by using the sphere 160 as the sliding member.

Second Embodiment
The drive mechanism 100A of this embodiment shown in FIG. 8 has the same configuration as the drive mechanism 100 of the first embodiment. Therefore, also in this embodiment, the same result based on the same configuration as the first embodiment is obtained.

  However, in this embodiment, a thrust needle bearing 160A is provided as a sliding member. The thrust needle bearing 160A is an example of a roller bearing and an example of a rolling bearing. The sliding member may be a bearing other than a needle bearing, such as a ball bearing.

  In the present embodiment, a leaf spring 151 is provided in the direction D1 of the wall 111a, a thrust needle bearing 160A is provided in the direction D1 of the leaf spring 151, and a spacer 152 is provided in the direction D1 of the thrust needle bearing 160A. Yes. That is, the thrust needle bearing 160 </ b> A as the sliding member is provided between the leaf spring 151 as the elastic member and the spacer 152.

  According to the present embodiment, the thrust needle bearing 160A is provided between the rotating member 141 and the wall 111a (opposing member), and when the rotating member 141 is rotated, the rotating member 141 is moved relative to the wall 111a. Slip. Therefore, according to the present embodiment, for example, an event in which the frictional resistance torque between the rotating member 141 and the wall portion 111a increases and the rotational load of the motor 120 increases is unlikely to occur.

  In this embodiment, the friction resistance torque reduction mechanism can be configured with a relatively simple configuration by using the thrust needle bearing 160A as the sliding member. Further, the frictional resistance torque reduction mechanism can be configured to be shorter in the axial direction.

<Third Embodiment>
The drive mechanism 100B of this embodiment shown in FIG. 9 has the same configuration as the drive mechanism 100A of the second embodiment. Therefore, also in this embodiment, the same result based on the same configuration as that of the second embodiment can be obtained.

  However, in the present embodiment, the drive mechanism 100B does not include the spacer 152, and the leaf spring 151 and the thrust needle bearing 160B are provided between the wall portion 111b of the housing 110 serving as the opposing member and the rotating member 141. It is pinched without going through.

  The wall 111b is provided in a flange shape by partially expanding the direction D1 side of the portion of the housing 110 where the first hole 113a is provided. The wall 111b is provided in an annular shape and has a surface orthogonal to the third rotation center Ax3.

  The leaf spring 151 and the thrust needle bearing 160 </ b> B are provided so as to surround the small diameter portion 141 a and the linear motion member 142 of the rotating member 141. That is, the small diameter portion 141a and the linear motion member 142 pass through the opening provided in the central portion of the leaf spring 151 and the thrust needle bearing 160B.

  The leaf spring 151 is located in the direction D1 of the wall 111b, the thrust needle bearing 160B is located in the direction D1 of the leaf spring 151, and the rotating member 141 is located in the direction D1 of the thrust needle bearing 160B. The positions of the leaf spring 151 and the thrust needle bearing 160B may be reversed.

  According to the present embodiment described above, for example, there is an effect that the number of parts and the mass of the drive mechanism 100B are reduced by the absence of the spacer 152.

<Modification of First Embodiment>
The drive mechanism 100C of the modification shown in FIG. 10 has the same configuration as the drive mechanism 100 of the first embodiment. Therefore, also by this modification, the same result based on the structure similar to the said 1st Embodiment is obtained.

  However, in this modification, the housing 110 includes a wall portion 111 and a wall portion 114. The wall 114 is detachably integrated with the wall 111. The part including the wall part 114 can be integrated with the wall part 111 by a coupler such as a screw. Further, for example, a portion including the wall portion 114 may be provided with a male screw portion or a female screw portion, and may be configured to be engaged with and integrated with the female screw portion or the male screw portion provided in the portion including the wall portion 111. The portion including the wall portion 111 may be referred to as a first member, a first portion, and a first divided body, and the portion including the wall portion 114 may be referred to as a second member, a second portion, and a second divided body. The wall part 114 is an example of an opposing member.

  Then, when the ball 160, the leaf spring 151, and the spacer 152 are taken out in a state where the portion including the wall portion 114 is separated from the portion including the wall portion 111, the end of the linear motion member 142 is exposed. Has been. A hexagonal hole 142 c is provided at the end of the linear motion member 142. Therefore, even in an emergency, the operator can move the linear motion member 142 by fitting and turning the hexagon wrench in the hexagonal hole 142c even when the rotating member 141 is locked. The linear motion member 142 may be provided with a handle that can be operated with a finger or an uneven portion in place of the hexagonal hole 142c, or a general-purpose tool such as a screwdriver different from the hexagonal wrench, a dedicated tool, or the like is fitted therein. Possible fitting structures may be provided.

  As mentioned above, although embodiment of this invention was illustrated, the said embodiment is an example to the last, Comprising: It is not intending limiting the range of invention. The above embodiment can be implemented in various other forms, and various omissions, replacements, combinations, and changes can be made without departing from the spirit of the invention. In addition, the specifications (structure, type, direction, shape, size, length, width, thickness, height, number, arrangement, position, material, etc.) of each configuration, shape, etc. are appropriately changed. Can be implemented.

  For example, in the above embodiment, the brake device 2 is configured as a leading trailing drum brake, but the present invention can also be configured as other types of brake devices. Further, the present invention can be implemented as a configuration corresponding to the other actuator of a brake device having a disc brake by one actuator and a drum brake by another actuator. Further, the opposing member may be a linear motion member.

  In the above-described embodiment, the configuration in which the operating member that moves the braking member is the cable 82 is exemplified. However, the operating member may be other than the cable 82 such as a rod or a lever. The actuating member may move the braking member by pushing instead of pulling.

  DESCRIPTION OF SYMBOLS 1 ... Wheel, 2 ... Brake device (brake for vehicles), 3 ... Brake shoe (braking member), 82 ... Cable (operation member), 110 ... Housing (opposing member), 111a, 114 ... Wall part (opposing member), DESCRIPTION OF SYMBOLS 120 ... Motor, 141 ... Rotating member, 142 ... Linear motion member, 151 ... Leaf spring (elastic member), 160 ... Ball, 160a ... Contact area | region, 160A, 160B ... Thrust needle bearing.

Claims (4)

An actuating member that moves the braking member to brake the wheel;
A motor,
A rotating member rotated by the motor;
A linear member that moves linearly with the rotation of the rotating member and moves the actuating member;
An elastic member;
An opposing member that elastically deforms the elastic member in the axial direction with the rotating member by movement of the rotating member in the axial direction of the rotating member;
A sliding member that is provided between the rotating member and the opposing member, and slides the rotating member relative to the opposing member when the rotating member is rotated;
Brake for vehicles equipped with.   The vehicular brake according to claim 1, wherein the sliding member has a convex curved contact area at a central portion as viewed from the axial direction.   The vehicle brake according to claim 1, wherein the sliding member is a sphere.   The vehicle brake according to claim 1, wherein the sliding member is a rolling bearing.

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