JP2018141544A - Vehicular brake - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicular brake having a motion conversion mechanism with a new configuration enabling a reduction of inconvenience, for example, a further reduction of a motor load.SOLUTION: A vehicular brake includes, for example: a motion conversion mechanism with a rotating member and a linear motion member; a one-way clutch that has a first rotation transmission section rotated in cooperation with a shaft of a motor and a second rotation transmission section rotated in cooperation with the rotating member, transmits rotation to the second rotation transmission section when the rotation is input from a shaft side of the motor to the first rotation transmission section and locks the rotation of the second rotation transmission section when rotational force is generated in the second rotation transmission member by input from the linear motion member; and a control section for performing control to rotate the motor and performing control to stop the motor on the basis of an increase in load of the motor corresponding to an increase in operation resistance in an operating portion from the shaft to the linear motion member when the linear motion member reaches a release position.SELECTED DRAWING: Figure 5

Description

  The present disclosure relates to a vehicle brake.

  2. Description of the Related Art Conventionally, there is known a vehicle brake that obtains a braking state by converting the rotation of a motor into a linear motion and moving a brake shoe or a brake pad in a motion conversion mechanism (for example, Patent Document 1).

Special table 2014-504711 gazette

  In this type of vehicle brake, if a self-locking screw is used as the motion conversion mechanism, it is possible to prevent the screw from rotating due to the force from the brake shoe and the position of the motion conversion mechanism and hence the brake shoe from changing.

  However, in such a configuration, since the self-locking screw has a larger friction loss when rotating compared to a screw that does not have a self-locking function, the torque required for the motor becomes larger, and the motor and thus the vehicle There is a possibility that problems such as increase in the size of the brake assembly and increase in energy consumption by the motor may occur.

  Accordingly, one of the objects of the present invention is to obtain a vehicle brake having a motion conversion mechanism with a new configuration with less inconvenience, for example, the load on the motor can be further reduced.

  The vehicle brake according to the present disclosure includes, for example, a motor having a shaft, a rotating member that rotates according to the rotation of the shaft, and a braking member that brakes a wheel, and the braking member according to the rotation of the rotating member. And a linear motion member that linearly moves between a braking position at which the wheel is braked and a release position at which the braking member releases the braking of the wheel, and a motion conversion mechanism that interlocks with the shaft. And a second rotation transmission portion that rotates in conjunction with the rotation member. When rotation is input from the shaft side to the first rotation transmission portion, the first rotation transmission portion rotates. A one-way clutch that transmits rotation to the two-rotation transmission unit and locks the rotation of the second rotation transmission unit when a rotational force is generated in the second rotation transmission unit by an input from the linear motion member; and the motor The The motor is controlled based on an increase in load of the motor in accordance with an increase in operating resistance in an operating part from the shaft to the linear motion member when the linear motion member reaches the release position. And a control unit that controls to stop the operation.

  The one-way clutch transmits the rotation to the rotating member of the motion converting mechanism when the rotation is input from the shaft of the motor, but when the rotation is input from the rotating member of the motion converting mechanism. Lock the rotation. Therefore, according to such a configuration, since it is not necessary to provide the motion conversion mechanism with a self-lock function, the vehicle brake can include a motion conversion mechanism that is more efficient than the self-lock screw. Therefore, according to the vehicle brake described above, for example, the output torque of the motor can be further reduced as compared with the configuration including the self-locking screw as the motion conversion mechanism.

  Further, the vehicle brake includes, for example, a buffer member that alleviates an increase in the operating resistance when the linear motion member reaches the release position. According to such a configuration, it is possible to suppress a sudden increase in the operating resistance of the operating portion, compared to the case where there is no buffer member. Therefore, for example, the rigidity and strength of the vehicle brake component can be set lower.

  In the vehicle brake, for example, the motion conversion mechanism has reversibility in which the rotating member can be rotated by the linear motion of the linear motion member. According to such a configuration, the vehicle brake can include a motion conversion mechanism with higher efficiency.

  The vehicle brake includes, for example, a reduction mechanism that includes a plurality of rotating parts and decelerates the rotation between the shaft and the rotating member, and the one-way clutch rotates with the largest diameter among the plurality of rotating parts. The component is provided adjacent to the rotating component in the axial direction. A one-way clutch having a small diameter may be difficult to employ because the stress of the component parts becomes excessively large in order to secure a required locking force. In this respect, according to such a configuration, for example, a one-way clutch having a diameter that can easily secure a margin for the stress of the component can be arranged more efficiently in the vehicle brake.

  In the vehicle brake, for example, the one-way clutch is interposed between the first rotation transmission unit and the second rotation transmission unit and receives a force from the first rotation transmission unit. When one of the reductions is generated and a force is received from the second rotation transmission portion, the coil spring is configured to generate the other of the diameter expansion and reduction, and contact friction between the coil springs and the coil springs. A friction brake portion that locks rotation and separates from the coil spring and allows rotation of the coil spring only when one of the expansion and contraction of the diameter by the first rotation transmission portion occurs. According to such a configuration, for example, a one-way clutch having a relatively simple configuration can be employed for a vehicle brake.

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 released 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 schematic cross-sectional view of a drive mechanism included in the vehicle brake of the embodiment, and is a diagram in a released state. FIG. 6 is an exemplary schematic sectional view of a drive mechanism included in the vehicle brake according to the embodiment, and is a diagram in a braking state. FIG. 7 is a schematic explanatory view illustrating a schematic configuration and operation of a one-way clutch included in the vehicle brake according to the embodiment, and is a diagram illustrating an initial state in which rotation is input from the first rotation transmission unit. . FIG. 8 is a schematic explanatory view showing a schematic configuration and operation of a one-way clutch included in the vehicle brake of the embodiment, and shows a state after FIG. 7 in which rotation is input from the first rotation transmission unit. FIG. FIG. 9 is a schematic explanatory view showing a schematic configuration and operation of a one-way clutch included in the vehicle brake of the embodiment, in which rotation is input from the first rotation transmission unit and rotation is transmitted to the second rotation transmission unit. It is a figure which shows the state performed. FIG. 10 is a schematic explanatory view showing a schematic configuration and operation of a one-way clutch included in the vehicle brake of the embodiment, and showing a state in which rotation is input from the second rotation transmission unit and rotation is locked. It is.

  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.

  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. ing.

(Brake device configuration)
FIG. 1 is a rear view of the brake device 2 from the rear of the vehicle. FIG. 2 is a side view of the brake device 2 from the outside in the vehicle width direction. FIG. 3 is a side view showing the operation of the brake shoe 3 (braking member) by the moving mechanism 8 of the brake device 2, and is a view in a released state (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 diagram in a braking state.

  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 a so-called drum brake. As shown in FIG. 2, the brake device 2 includes two brake shoes 3 that are separated from each other in the front-rear direction. As shown in FIGS. 3 and 4, the two brake shoes 3 extend in an arc shape along the inner peripheral surface 4 a of the cylindrical drum 4. The drum 4 rotates integrally with the wheel 1 around the 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 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 an actuator that moves 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 example, for braking while traveling, and the motor 120 is used, for example, for braking during parking. That is, the brake device 2 is an example of an electric parking brake. The motor 120 may 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 rotation center C. That is, the back plate 6 extends substantially along the direction intersecting the rotation center C, specifically, substantially along the 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 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 be used for both driving wheels and non-driving 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.

<Brake shoe operation by wheel cylinder>
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. Specifically, as shown in FIG. 3, the lower end 3a of the brake shoe 3 is supported by the back plate 6 (see FIG. 2) so as to be rotatable around the rotation center C11. The rotation center C11 is substantially parallel to the rotation center C of the wheel 1. Further, as shown in FIG. 2, the wheel cylinder 51 is supported by 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 C11 (see FIGS. 3 and 4) 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 of the drum 4 come into contact with each other as shown in FIG. The drum 4 and thus the wheel 1 (see FIG. 1) are braked by the friction between the lining 31 and the inner peripheral surface 4a. 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 not in contact with the inner peripheral surface 4a (non-braking position Pn, release position, initial position, see FIG. 3). The return member 32 is an elastic member such as a coil spring, for example. .

<Configuration of moving mechanism and operation of brake shoe by moving mechanism>
Moreover, the brake device 2 includes a moving mechanism 8 shown in FIGS. The moving mechanism 8 moves the two brake shoes 3 from the non-braking position Pn to the braking position Pb based on the operation of the driving mechanism 100 including the motor 120 (see FIG. 5). The moving mechanism 8 is provided outside the back plate 6 in the vehicle width direction. The moving mechanism 8 includes a lever 81, a cable 82, and a strut 83. The lever 81 is located between one of the two brake shoes 3, for example, the left brake shoe 3 </ b> L in FIGS. 3 and 4, and the back plate 6. It is provided so as to overlap in the axial direction. The lever 81 is supported by the brake shoe 3L so as to be rotatable around the rotation center C12. The rotation center C12 is located at the end of the brake shoe 3L on the side away from the rotation center C11 (upper side in FIGS. 3 and 4), and is substantially parallel to the rotation center C11. The cable 82 moves the lower end portion 81a of the lever 81 on the side farther from the rotation center C12, for example, in a direction approaching the right brake shoe 3R in FIGS. 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 C12 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 moves to the right in FIG. 4, when the lever 81 moves in a direction approaching the brake shoe 3 </ b> R (arrow a), the lever 81 passes through the strut 83. Press the brake shoe 3R (arrow b). As a result, the brake shoe 3R rotates around the rotation center C11 from the non-braking position Pn (FIG. 3) (arrow c in FIG. 4) and moves to the braking position Pb (FIG. 4) in contact with the inner peripheral surface 4a of the drum 4. Move. In this state, the connection position P2 between the cable 82 and the lever 81 corresponds to the power point, the rotation center C12 corresponds to the fulcrum, and the connection position P1 between the lever 81 and the strut 83 corresponds to the action point. Furthermore, when the brake shoe 3R is in contact with the inner peripheral surface 4a and the lever 81 moves to the right in FIG. 4, that is, in the direction in which the strut 83 pushes the brake shoe 3R (arrow b), the strut 83 is stretched. Accordingly, 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). Thereby, the brake shoe 3L rotates around the rotation center C11 from the non-braking position Pn (FIG. 3) and moves to the braking position Pb (FIG. 4) in contact with the inner peripheral surface 4a of the drum 4. In this way, the brake shoes 3L and 3R are both moved from the non-braking position Pn (FIG. 3) to the braking position Pb (FIG. 4) 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)
FIG. 5 is a cross-sectional view of the driving mechanism 100 in a released state. FIG. 6 is a cross-sectional view of the driving mechanism 100 in a braking state. The drive mechanism 100 is an example of a vehicle brake.

  1, 5 and 6 moves the two brake shoes 3 from the non-braking position Pn (release position) to the braking position Pb via the moving mechanism 8 described above. The drive mechanism 100 is positioned inward 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 (see FIG. 1, only a part of which is shown in FIG. 5), a motor 120, a speed reduction mechanism 130, a motion conversion mechanism 140, and a one-way clutch 160. .

  The housing 110 supports the motor 120, the speed reduction mechanism 130, the motion conversion mechanism 140, and the one-way clutch 160. 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 surrounded by a wall 111 is provided in the housing 110. The motor 120, the speed reduction mechanism 130, the motion conversion mechanism 140, and the one-way clutch 160 are accommodated in an accommodation chamber provided in the housing 110 and covered with a 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 housing 121 and a housing component housed in the housing 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 housing 121 in the D1 direction (rightward in FIG. 5) along the first rotation center Ax1 of the motor 120. The motor 120 is driven by driving power based on the control signal, and rotates the shaft 122. The shaft 122 may be referred to as an output shaft. In the following, for convenience of explanation, the right side in FIG. 5 is referred to as the front in the D1 direction, and the left side in FIG. 5 is referred to as the rear in the D1 direction or the opposite direction to the D1 direction.

  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. The first gear 131, the second gear 132, and the third gear 133 are examples of rotating parts. Further, the speed reduction 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 behind the input gear 132a in the direction D1 (leftward in FIG. 5). 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 input gear 133 a of the third gear 133 meshes with the output gear 132 b of the second gear 132. The number of teeth of the input gear 133a 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 input gear 133a can be referred to as a driven gear. The third gear 133 has a disc-shaped base portion 133b and a protrusion 161 protruding from the base portion 133b in the D1 direction. A through hole 133c through which the hub 141a of the rotating member 141 passes is provided at the center of the base portion 133b. The third gear 133 is supported by the hub 141a so as to be rotatable around the third rotation center Ax3. 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. Further, the speed reduction mechanism 130 may include a planetary gear mechanism. The planetary carrier of the planetary gear mechanism is an example of a rotating component.

  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 hub 141a and a flange 162 projecting radially outward from the hub 141a. The hub 141a is configured in a cylindrical shape extending in the D1 direction, and penetrates the flange 162 in the D1 direction. The flange 162 protrudes in a disk shape from the center position in the D1 direction of the hub 141a in the radial direction of the third rotation center Ax3.

  At least the teeth or all of the first gear 131, the second gear 132, and the third gear 133 can be made of a synthetic resin material. However, the present invention is not limited to this, and at least one of the first gear 131, the second gear 132, and the third gear 133 may be partially or entirely made of a metal material.

  A thrust bearing 143 is positioned between the front end surface of the flange 162 in the D1 direction and the rear end portion 112a of the cylindrical portion 112 provided in the housing 110 in the D1 direction. 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 flange 162 and thus the rotating member 141 are rotatably supported by the housing 110 via a thrust bearing 143.

  The hub 141 a is inserted into a cylindrical radial bearing 144 housed at the tip of the cylindrical portion 112. The hub 141a and 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 passes through the hub 141a and the flange 162. 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, a connecting portion 142b, and a flange 142c.

  The rod-like portion 142 a is inserted into a hole 113 b provided in the cylindrical portion 112 of the housing 110. The cross section of the hole 113b is, for example, a non-circular shape having two plane portions (guide surfaces) parallel to each other. By providing the flange 142c so as to face the flat portion of the hole 113b, the rotation of the flange 142c, and hence the linear motion member 142 is restricted. 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.

  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 hole 113b, the linear motion member 142 is moved along the axial direction of the third rotation center Ax3 with the non-braking position Pn (FIG. 5) and the braking position ( (Not shown).

<Motor rotation load increasing mechanism>
As shown in FIG. 5, a disc-shaped support member 152 is coupled to the end of the linear motion member 142 at the rear (left side in FIG. 5) in the direction D <b> 1 by a coupling tool 153 such as a screw. . A coil spring 151 is provided between the support member 152 and the base portion 133 b of the third gear 133. The coil spring 151 is formed in a spiral shape extending along the third rotation center Ax3 so as to surround the hub 141a and the linear motion member 142. The coil spring 151 is an example of a buffer member and can also be referred to as an elastic member. Further, the support member 152 and the coupler 153 can be included in the linear motion member 142.

  When the linear motion member 142 moves forward in the direction D1 (rightward in FIG. 5) due to the rotation of the motor 120, the coil spring 151 rotates with the support member 152 that is a part of the linear motion member 142. Between the base 141b of the member 141, it is elastically compressed in the axial direction of the coil spring 151, that is, the axial direction of the third rotation center Ax. The coil spring 151 is an example of an elastic member. Due to the increase in the elastic compression reaction force of the coil spring 151, the force in the normal direction of the thread surface at the female screw portion 145a and the male screw portion 145b increases, 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 unit 123 (FIG. 5) of the motor 120 detects the load torque based on the driving current of the motor 120 and the like, thereby limiting the forward movement of the linear motion member 142 in the D1 direction, That is, it can be detected that the linear motion member 142 is located at the predetermined non-braking position Pn, and the rotation of the motor 120 can be stopped when the non-braking position Pn is reached. That is, in the present embodiment, the motor rotation load increasing mechanism is configured mainly by the coil spring 151 as an elastic member that applies an elastic reaction force to the rotating member 141 in the axial direction. At this time, the coil spring 151 gradually increases the load of the motor 120 as the linear motion member 142 approaches the non-braking position Pn. If the coil spring 151 is not provided and, for example, the linear motion member 142 is configured to directly contact the housing 110 at the non-braking position Pn, the load on the motor 120 increases abruptly. In this respect, the coil spring 151 can be said to be an example of a buffer member that alleviates an increase in the load of the motor 120, that is, an increase in the operating resistance of the linear motion portion and the rotation portion. Note that the motor rotation load increasing mechanism is not limited to the configuration in which the linear motion resistance of the linear motion member 142 or the rotational resistance of the third gear 133 increases when the linear motion member 142 reaches the non-braking position Pn. Any configuration may be used as long as the operation resistance (linear motion resistance or rotational resistance) due to friction in any of the motion portions (linear motion portion or rotational portion) from the shaft 122 to the linear motion member 142 increases.

<One way clutch>
As shown in FIGS. 5 and 6, in the present embodiment, a one-way clutch 160 is provided in the rotation transmission path between the speed reduction mechanism 130 and the motion conversion mechanism 140. 7 to 10 are schematic explanatory views showing a schematic configuration and operation of the one-way clutch 160. FIG. 7 is a view showing an initial state in which rotation is input from the protrusion 161, and FIG. FIG. 9 is a diagram illustrating a state after the rotation is input from FIG. 7, and FIG. 9 is a diagram illustrating a state in which the rotation is input from the protrusion 161 and the rotation is transmitted to the flange 162.

  The one-way clutch 160 includes a protrusion 161, a flange 162, a coil spring 163, and a ring 164. The ring 164 has a cylindrical shape centered on the third rotation center Ax3. Further, the ring 164 has a protrusion 164b protruding outward in the radial direction. As shown in FIG. 5, the protrusion 164 b is inserted into a notch 111 a (concave portion) provided in the wall portion 111 of the housing 110. The notch 111a and the protrusion 164b function as a detent for the ring 164. In addition, the notch 111a and the protrusion 164b are not limited in the rotation preventing structure of the ring 164.

  As an example, the coil spring 163 is configured by winding a wire having a quadrangular cross-section spirally around the third rotation center Ax3. In the set state in which no circumferential force is applied to the end of the wire, the outer periphery of the coil spring 163 is in contact with the inner peripheral surface 164a of the ring 164, and the inner peripheral surface 164a is in the radial direction of the third rotation center Ax3. It is elastically pressed outward. At both ends of the wire rod of the coil spring 163, hook portions 163a and 163b bent in a hook shape radially inward or turned back in the circumferential direction are provided.

  As described above, the protrusion 161 is provided on the third gear 133. Therefore, the protrusion 161 rotates around the third rotation center Ax3 together with the third gear 133. As shown in FIG. 7, the protrusion 161 is disposed between the third rotation center Ax <b> 3 and the inner periphery of the coil spring 163 at a position spaced from the inner periphery of the coil spring 163. In this embodiment, the protrusion 161 is provided to extend the coil spring 163 in the circumferential direction by being hooked from the hooks 163a and 163b and the hooks of the hooks 163a and 163b. When the end portions (hook portions 163a and 163b) of the coil spring 163 are pulled in the circumferential direction, the diameter of the coil spring 163 decreases. As an example, the protrusion 161 is configured in an arc shape narrower than the circumferential interval in the hook of the hook portions 163a and 163b when viewed from the axial direction of the third rotation center Ax. It is not limited.

  On the other hand, the flange 162 is provided on the rotating member 141 as described above. Therefore, the flange 162 rotates around the third rotation center Ax3 integrally with the rotating member 141. As shown in FIG. 7, the flange 162 is disposed between the third rotation center Ax <b> 3 and the inner periphery of the coil spring 163 at a position spaced from the inner periphery of the coil spring 163. However, in the present embodiment, the end portions 162a and 162b of the flange 162 are provided so that the coil spring 163 is contracted in the circumferential direction by pushing the hook portions 163a and 163b from outside the hooks of the hook portions 163a and 163b. It has been. When the end portions (hook portions 163a and 163b) of the coil spring 163 are compressed in the circumferential direction, the diameter of the coil spring 163 increases. The flange 162 is, for example, a sector shape that is narrower than the interval in the circumferential direction outside the hooks of the hook portions 163a and 163b when viewed from the axial direction of the third rotation center Ax (as an example, a sector shape having an inner angle larger than 180 °). However, the present invention is not limited to this.

  7 to 9 show the operation of the one-way clutch 160 when rotation is input from the protrusion 161 in the counterclockwise direction. As shown in FIG. 7, when the protrusion 161 rotates and pulls the hooking portion 163a from the inside of the hook, the diameter of the coil spring 163 becomes smaller as shown by the arrow Di, and the coil spring 163 becomes smaller as shown in FIG. A gap is formed between the outer periphery of the spring 163 and the inner peripheral surface 164a of the ring 164. Thereby, the coil spring 163 can rotate integrally with the protrusion 161. Further, when the coil spring 163 rotates, the hooking portion 163 a of the coil spring 163 comes into contact with the end portion 162 a of the flange 162. As a result, the one-way clutch 160 enters a rotation transmission state in which the protrusion 161, the hook portion 163a of the coil spring 163, and the flange 162 rotate integrally in the counterclockwise direction. 7-9, the clearance gap is maintained between the outer periphery of the coil spring 163, and the internal peripheral surface 164a of the ring 164. FIG. Although not shown, even when the protrusion 161 rotates in the clockwise direction, the one-way clutch 160 similarly rotates the protrusion 161, the hook portion 163b of the coil spring 163, and the flange 162 in the clockwise direction. Rotation transmission state.

  FIG. 10 is a schematic explanatory view showing a schematic configuration and operation of the one-way clutch 160, and shows a state in which rotation is input from the flange 162. As shown in FIG. 10, when the flange 162 rotates counterclockwise and the end 162b of the flange 162 pushes the hooking portion 163b from the outside of the hook, the diameter of the coil spring 163 becomes smaller as indicated by the arrow Do. The outer periphery of the coil spring 163 is pressed against the inner peripheral surface 164 a of the ring 164. In this case, the coil spring 163 cannot rotate with respect to the ring 164 and thus the housing 110 due to contact friction between the outer periphery of the coil spring 163 and the inner peripheral surface 164 a of the ring 164. That is, the rotation of the flange 162 and thus the rotating member 141 is locked.

  Thus, when the rotation from the third gear 133, that is, the rotation from the shaft 122 of the motor 120 is input to the protrusion 161, the one-way clutch 160 transmits the rotation from the protrusion 161 via the coil spring 163. This is transmitted to the flange 162 and thus to the rotating member 141. On the other hand, when the rotation of the rotating member 141 based on the linear motion of the linear motion member 142 is input to the flange 162, the one-way clutch 160 is rotated by the contact friction between the coil spring 163 and the ring 164, that is, the rotational member. The rotation of 141 is locked. That is, the one-way clutch 160 can transmit rotation from the motor 120 to the motion conversion mechanism 140. On the other hand, the one-way clutch 160 cannot transmit rotation from the motion conversion mechanism 140 to the motor 120, and the rotation of the rotating member 141 of the motion conversion mechanism 140 in that case is locked. The protrusion 161 is an example of a first rotation transmission unit, the flange 162 is an example of a second rotation transmission unit, and the ring 164 is an example of a friction brake unit.

  As described above, since the drive mechanism 100 (vehicle brake) of the present embodiment includes the one-way clutch 160 between the shaft 122 and the linear motion member 142 of the motor 120, the motion conversion mechanism 140 is self-excited. There is no need to provide a lock function. Therefore, for example, a screw mechanism having a smaller friction torque can be adopted as the motion conversion mechanism 140, and the output torque of the motor 120 can be set smaller. Thereby, for example, the effect that the motor 120 and hence the drive mechanism 100 can be reduced in size and the energy consumption by the motor 120 can be reduced can be obtained. In addition, for example, a screw mechanism having a larger pitch can be employed as the motion conversion mechanism 140, so that the rotational speed can be further increased and the responsiveness of the drive mechanism 100 can be improved.

  In the present embodiment, for example, the drive mechanism 100 includes a coil spring 151 (buffer member) that reduces an increase in operating resistance when the linear motion member 142 reaches the non-braking position Pn (release position). . According to such a configuration, it is possible to suppress an abrupt increase in the operating resistance of the operating portion as compared with the case where the coil spring 151 is not provided. Therefore, for example, the rigidity and strength of the components of the drive mechanism 100 can be set lower. The buffer member is not limited to the coil spring 151, and may be another elastic member such as a disc spring or an elastomer, or an elastic member that increases the operating resistance as the linear motion member 142 moves. There may be no cushioning member.

  Further, in the present embodiment, for example, the motion conversion mechanism 140 has reversibility that allows the rotation member 141 to rotate by the linear motion of the linear motion member 142. That is, the drive mechanism 100 can include a more efficient motion conversion mechanism 140 having reversibility.

  In the present embodiment, for example, the one-way clutch 160 includes a third gear 133 having the largest diameter among the first gear 131, the second gear 132, and the third gear 133 (rotating parts) included in the speed reduction mechanism 130. The third rotation center Ax3 is provided adjacent to the axial direction. According to such a configuration, for example, as compared with a configuration in which the one-way clutch 160 is disposed adjacent to the first gear 131 or the second gear 132 having a smaller diameter, a margin is secured in the stress of the component parts. The one-way clutch 160 having a relatively large diameter that is easy to do can be arranged more efficiently in the drive mechanism 100.

  Further, in this embodiment, for example, when the coil spring 163 of the one-way clutch 160 receives a force from the protrusion 161 (first rotation transmission portion), the diameter is reduced, and the flange 162 (second rotation transmission portion). The ring 164 (friction brake part) locks the rotation of the coil spring 163 by contact friction with the coil spring 163 having an enlarged diameter, and is formed by the protrusion 161. Only when the diameter of the coil spring 163 is reduced, the coil spring 163 is allowed to rotate away from the coil spring 163. According to such a configuration, for example, the one-way clutch 160 having a relatively simple configuration can be employed in the drive mechanism 100. The one-way clutch 160 is not limited to the configuration of the embodiment. For example, when the diameter is reduced by pulling the coil spring in the circumferential direction, the contact friction increases with the friction brake portion radially inward. Thus, the rotation may be locked. In this configuration, rotation is transmitted when the coil spring is compressed in the circumferential direction. The protrusion 161 and the third gear 133 may be separate members that rotate integrally, and the flange 162 and the rotating member 141 may be separate members that rotate integrally.

  As mentioned above, although embodiment of this invention was illustrated, the said embodiment is an example and 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.

  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. Further, the vehicle brake may be provided with a one-way clutch of a type or configuration different from that of the one-way clutch 160, or may be a disc brake. When the vehicle brake is a disc brake, the braking member is a brake pad.

  DESCRIPTION OF SYMBOLS 3 ... Brake shoe (braking member), 100 ... Drive mechanism (brake for vehicles), 120 ... Motor, 122 ... Shaft (operation part), 123 ... Control part, 130 ... Deceleration mechanism, 131 ... First gear (rotary component, Operation part), 132 ... Second gear (rotary part, operation part), 133 ... Third gear (rotation part, operation part), 140 ... Motion conversion mechanism, 141 ... Rotation member (operation part), 142 ... Linear motion member (Operation part), 151 ... coil spring (buffer member), 160 ... one-way clutch, 161 ... projection (first rotation transmission part), 162 ... flange (second rotation transmission part), 163 ... coil spring, 164 ... ring ( Friction brake part), Pb ... braking position, Pn ... non-braking position (release position).

Claims (5)

A motor having a shaft;
A rotating member that rotates in accordance with the rotation of the shaft, a braking member that is connected to a braking member that brakes a wheel, and in which the braking member brakes the wheel as the rotating member rotates, and the braking member includes the braking member A linear motion member that linearly moves between a release position for releasing braking of the wheel, and a motion conversion mechanism having
A first rotation transmission portion that rotates in conjunction with the shaft; and a second rotation transmission portion that rotates in association with the rotation member, and rotation is input to the first rotation transmission portion from the shaft side. In this case, rotation is transmitted to the second rotation transmission unit, and when a rotational force is generated in the second rotation transmission unit by the input from the linear motion member, the one-way that locks the rotation of the second rotation transmission unit. Clutch,
Based on an increase in load of the motor in accordance with an increase in operating resistance in an operating part from the shaft to the linear motion member when the linear motion member reaches the release position while controlling the motor to rotate. A control unit for controlling the motor to stop,
Brake for vehicles equipped with.   The vehicle brake according to claim 1, further comprising a buffer member that reduces an increase in the operation resistance when the linear motion member reaches the release position.   3. The vehicle brake according to claim 1, wherein the motion conversion mechanism has reversibility in which the rotating member can rotate by the linear motion of the linear motion member. A reduction mechanism that includes a plurality of rotating parts and decelerates rotation between the shaft and the rotating member;
The vehicle according to any one of claims 1 to 3, wherein the one-way clutch is provided adjacent to the rotating component having the largest diameter among the plurality of rotating components in the axial direction of the rotating component. brake.   The one-way clutch is interposed between the first rotation transmission portion and the second rotation transmission portion, and when receiving a force from the first rotation transmission portion, one of diameter expansion and contraction occurs and the first way clutch The coil spring is configured to lock the rotation of the coil spring by contact friction between the coil spring configured to generate the other one of the expansion and contraction of the diameter when receiving a force from the two-rotation transmission unit, and the first rotation. 5. A friction brake portion that is spaced apart from the coil spring and allows rotation of the coil spring only when one of expansion and contraction of the diameter by the transmission portion occurs. The brake for vehicles as described in one.

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