WO2017150449A1

WO2017150449A1 - Electrically operated brake

Info

Publication number: WO2017150449A1
Application number: PCT/JP2017/007505
Authority: WO
Inventors: 優一竹尾
Original assignee: 株式会社アドヴィックス
Priority date: 2016-02-29
Filing date: 2017-02-27
Publication date: 2017-09-08
Also published as: JP6458748B2; JP2017155774A

Abstract

In a recess 13a and/or a protrusion 15b constituting a recessed/protruding engaging part 22 capable of regulating rotation of a piston 13 about an axis relative to a friction pad 15, in a surface for regulating the rotation of the piston 13 about the axis, an inclined surface 13a2 is formed only in the surface of the side regulating the piston 13 rotation that is in the same direction that a rotating member rotates when a propulsion member is moved linearly away from a disk rotor, the inclined surface 13a2 causing, due to the rotation of the piston 13 in said direction, the friction pad 15 and the piston 13 to separate in the axial direction.

Description

Electric brake

The present invention relates to an electric brake mounted on a vehicle such as an automobile.

As the above-mentioned electric brake, for example, the one described in Patent Document 1 is known. This electric brake is configured such that a piston that presses the friction pad against the disk rotor is pressed by a propulsion member connected to a rotating member via a screw mechanism. The rotating member is rotationally driven by an electric motor through a driving mechanism. The propelling member is disposed in a state that it can move relative to the piston in the axial direction and is restricted in rotation in the circumferential direction. The piston and the friction pad are formed with a concave and convex engaging portion capable of restricting the rotation of the piston with respect to the friction pad, that is, the rotation of the piston around the axis so that the piston is not rotated by the driving of the rotating member. .

JP 2010-190348

However, in the above-described configuration, for example, when the rotating member is driven to move the piston backward so that the piston is moved backward when replacing the friction pad, which is a consumable item, the propelling member moves backward. When it comes into contact with a stopper on the side (such as a flange of a rotating member), the screw mechanism is tightened (locked) and the driving torque of the rotating member is transmitted to the propelling member as it is, and the propelling member attempts to rotate the piston. The power to do soars. Although the rotation of the piston due to this is regulated by the concave and convex engaging portion provided between the friction pads, the load applied to the electric motor and the drive mechanism increases rapidly due to the sudden stop of the rotation that occurs at that time. Such a sudden increase in load is not preferable in order to improve the durability of the electric motor and the drive mechanism.

An object of the present invention is to provide an electric brake capable of improving the durability of an electric motor and a drive mechanism with a simple configuration.

In order to solve the above-mentioned problem, the invention according to claim 1 includes a friction pad that abuts against a disk rotor to generate a braking force, a piston that presses the friction pad toward the disk rotor, and the piston. A propulsion member that can move linearly in the axial direction of the piston to be propelled toward the disk rotor; a rotation member that is coupled to the propulsion member via a screw mechanism to move the propulsion member; and a drive mechanism. An electric brake including an electric motor that rotationally drives the rotating member via the propulsion member, and the propelling member is disposed in a state of being relatively movable in the axial direction with respect to the piston and being restricted in rotation in the circumferential direction of the piston, In the electric brake in which the piston and the friction pad are provided with a concave and convex engaging portion capable of restricting the rotation of the piston around the axis with respect to the friction pad. Of at least one of the concave and convex portions constituting the concave-convex engaging portion, the rotation when the propulsion member is directly moved to the anti-disk rotor side among the restriction surfaces for rotation around the axis facing the circumferential direction of the piston. Only on the surface that restricts the rotation of the piston in the same direction as the rotation direction of the member, an inclined surface that separates the friction pad and the piston in the axial direction is formed by the rotation of the piston in the direction. It is a summary.

According to the first aspect of the present invention, for example, when the rotating member is driven to move the piston backward to move the propelling member to the side opposite to the disk rotor when the friction pad is replaced, the locked state as described above is obtained. Even if the force for the propelling member to rotate the piston suddenly increases, the friction pad and the piston are separated in the axial direction by the inclined surface provided in the concave-convex engaging portion. The part is consumed as energy required for the separation movement, and the load applied to the electric motor and the driving mechanism is reduced as much as the reaction force. Therefore, durability of the electric motor and the drive mechanism can be improved.
Further, for example, if the friction pad and the piston are further separated in the axial direction and the engagement of the concave and convex engaging portions is released, the load applied to the electric motor and the drive mechanism is further reduced, and the durability is further improved. It becomes possible. In the present invention, such an effect can be obtained with a simple configuration in which an inclined surface is formed in the concave-convex engaging portion.

Further, in the present invention, the above-described inclined surface is a side that restricts the rotation of the piston in the same direction as the rotation direction of the rotating member when the propelling member is moved directly to the counter-disk rotor side among the above-described restricting surfaces. For example, on the opposite regulation surface, that is, on the side that regulates the rotation of the piston in the same direction as the rotation direction of the rotation member when the propulsion member moves linearly (advances) to the disk rotor side. Unlike the aspect in which the surface is provided with an inclined surface that separates the friction pad and the piston in the axial direction by the rotation of the piston in this direction, the friction pad is moved to the disc rotor side by the inclined surface when the piston moves forward, that is, during braking. The phenomenon that the braking force is fluctuated (increased) due to being pushed out does not occur.

1 is a cross-sectional view schematically showing an embodiment of an electric brake according to the present invention. The enlarged view which similarly showed one Embodiment of the uneven | corrugated engagement part. The enlarged view which similarly showed the other example of the uneven | corrugated engagement part. The enlarged view which similarly showed the other example of the uneven | corrugated engagement part.

Hereinafter, embodiments of the present invention will be specifically described. However, the present invention is not limited to the following embodiments as long as the gist of the present invention is not exceeded.

FIG. 1 is a sectional view schematically showing an embodiment of an electric brake according to the present invention. The electric brake (electric disc brake) 10 of this embodiment has a hydraulic service brake function and an electric parking brake (EPB) function.
That is, the hydraulic service brake function will be described. A bottomed cylindrical piston 13 accommodated in the cylinder 12 of the caliper 11 so as to be slidable in the axial direction (axis L direction) is a hydraulic pressure source such as a master cylinder (not shown). Driven by the hydraulic pressure introduced into the cylinder 12 from above, the friction pad 15 disposed between the piston 13 and the disk rotor 14 is pressed against the disk rotor 14 to generate a braking force.

On the other hand, the electric parking brake function will be described. The caliper 11 is provided with an electric actuator A that drives the piston 13 when the vehicle is parked. That is, the electric actuator A is fixed to the caliper 11 and the propulsion member 16 disposed in the piston 13 so as to be relatively movable in the axial direction, the rotating member 18 connected to the propulsion member 16 via the screw mechanism 17. An electric motor 19 and a drive mechanism 20 for transmitting the rotational output of the electric motor 19 to the rotating member 18.

The rotating member 18 is supported by the caliper 11 so as to be rotatable around the same axis as the center axis L of the cylinder 12 and the piston 13. A front end side (left side in FIG. 1) of the rotating member 18 is accommodated in the cylinder 12, and a male screw 18 a constituting the screw mechanism 17 is formed on the front end side portion. The rotating member 18 is integrally formed with a flange-like stopper 18b on the rear end side (right side in FIG. 2) of the male screw portion 18a in the cylinder 12.

The front end side of the propelling member 16 is inserted into the piston 13, and a female screw portion 16 a that is screwed with the male screw portion 18 a of the rotating member 18 is formed on the rear end side. The female screw portion 16a constitutes a screw mechanism 17 together with the male screw portion 18a. When the rotating member 18 rotates, the rotation is converted by the screw mechanism 17 into a linear movement of the propelling member 16, that is, movement in the direction of the axis L. The outer peripheral surface of the propulsion member 16 and the inner peripheral surface of the piston 13 are provided with, for example, ridges and recesses (not shown) extending in the direction of the axis L, and the relative rotation between the propulsion member 16 and the piston 13 is restricted. The

The drive mechanism 20 is provided so as to rotationally connect the rear end portion of the rotary member 18 exposed to the outside of the caliper 11 and the rotary shaft of the electric motor 19. For example, the drive mechanism 20 includes a plurality of gears as shown in FIG. The rotational output is decelerated and transmitted to the rotating member 18. The electric motor 19 and the drive mechanism 20 are covered with a cover member (not shown) and are protected from being exposed to water.

When the electric motor 19 is driven to move the piston 13 forward, that is, to the disk rotor 14 (hereinafter referred to as forward rotation driving), the rotating member 18 is rotationally driven by the driving mechanism 20 and the propelling member 16 is moved in the forward direction. Move. When the front end portion of the propulsion member 16 presses the inner end portion of the piston 13, the piston 13 moves forward and presses the friction pad 15 against the disk rotor 14. As a result, a braking force for parking is generated. At this time, the reaction force received by the piston 13 from the disk rotor 14 is transmitted to the rotating member 18 via the propelling member 16, but the stopper 18 b of the rotating member 18 is pressed against the inner end surface of the cylinder 12 via the thrust bearing 21. Thus, the rotation member 18 is prevented from coming off.

When releasing braking applied to parking, such as when the vehicle is starting, the propulsion member 16 is moved backward by driving the electric motor 19 in the direction opposite to the forward rotation drive (hereinafter referred to as reverse rotation drive). Then, the pressing of the friction pad 15 by the piston 13 is released.

By the way, when the propelling member 16 is driven in the forward direction, a force for rotating the propelling member 16 acts on the propelling member 16 due to friction between the male screw portion 18a and the female screw portion 16a of the screw mechanism 17. This rotational force is transmitted to the piston 13 whose relative rotation with the propulsion member 16 is restricted. In the present embodiment, the front end surface of the piston 13 and the back plate 15a of the friction pad 15 are provided with a concave and convex engaging portion 22 that can restrict the rotation of the piston 13 around the axis L (rotation around the axis) with respect to the friction pad 15; The rotation of the piston 13 with respect to the caliper 11 is stopped.

FIG. 2 is an enlarged view showing the periphery of the concave-convex engaging portion 22 as viewed from below in FIG. The concave / convex engaging portion 22 includes a columnar convex portion 15b provided on the surface of the metal back plate 15a on the piston 13 side, and a concave portion 13a formed on the front end surface of the piston 13 into which the convex portion 15b is inserted. Become. The convex portion 15b may be formed by stamping a part of the back plate 15a, or may be formed of a member (such as a cylindrical pin) different from the one fixed to the substrate portion of the back plate 15a. May be. Thus, by providing the convex part 15b in the back plate 15a and the concave part 13a in the piston 13, the convex part 15b is formed in the friction pad 15 by, for example, press punching, and the piston 13 is formed by cutting or forging. The concave / convex engaging portion 22 can be configured by a relatively easy method such as forming the concave portion 13a on the end surface.

Each of the concave portion 13a and the convex portion 15b has a regulating surface that faces the circumferential direction around the piston 13, that is, the axis L, and regulates the rotation of the piston 13 around the axis with respect to the friction pad 15. As the restriction surfaces, there are a restriction surface that restricts the accompanying rotation of the piston 13 during the forward rotation driving and a restriction surface that restricts the accompanying rotation of the piston 13 during the reverse rotation driving. In FIG. 2, the piston 13 tries to rotate from the upper side to the lower side of the drawing with respect to the friction pad 15 at the time of forward rotation, and the lower side of the drawing with respect to the friction pad 15 at the time of reverse rotation driving. Trying to move up from the top. That is, the restriction surfaces at the time of forward rotation drive are the restriction surfaces 13a1 and 15b1 on the upper side in FIG. 2 among the restriction surfaces facing the circumferential direction (vertical direction in FIG. 2). Further, the restriction surfaces at the time of reverse rotation driving are the lower restriction surfaces 13a2 and 15b2 in FIG.

In the present embodiment, the regulation surfaces 13a1 and 15b1 on the side that regulates the rotation of the piston 13 in the same direction as the rotation direction of the rotation member 16 when driving forward, that is, when the propulsion member 16 is moved linearly to the disk rotor 14 side. , Both extend parallel to the axis L and are not inclined. In this case, the abutting portions (regulating surfaces 13a1, 15b1) between the concave portion 13a and the convex portion 15b may not be inclined. For example, even if the tip of the convex portion 15b is chamfered, the chamfered portion does not have to abut on the surface facing the circumferential direction of the concave portion 13a during forward rotation driving.

Further, in the present embodiment, the regulating surface 13a2 on the side that regulates the rotation of the piston 13 in the same direction as the rotating direction of the rotating member 16 at the time of reverse rotation driving, that is, when the propelling member 16 is moved directly to the counter disk rotor 14 side. 15b2, only the regulation surface 13a2 of the recess 13a is inclined with respect to the axis L. This inclination is an inclination in a direction to separate the friction pads 15 and the piston 13 from each other in the axis L direction by pressing the restricting surfaces 13a2 and 15b2 by the rotation of the piston 13 during reverse rotation driving. . Specifically, the regulation surface 13a2 is inclined so that the opening side (the friction pad 15 side) of the recess 13a is wider in the circumferential direction than the back side (the anti-friction pad 15 side).

In this case, for example, the regulating surface 15b2 of the convex portion 15b may be inclined at the same inclination as the regulating surface 13a2 of the concave portion 13a. According to this, both the regulation surfaces 13a2 and 15b2 can be brought into contact with each other, and the stress caused by the contact between both can be further dispersed.

In the present embodiment configured as described above, the propulsion member 16 comes into contact with the stopper 18b during reverse rotation driving in the replacement operation of the friction pad 15 and the screw mechanism 17 is locked, and the propulsion member 16 rotates the piston 13. Even if the force to increase suddenly increases, the friction pad 15 and the piston 13 are separated in the direction of the axis L by the contact between the inclined regulating surface 13a2 of the concave portion 13a and the convex portion 15b. Therefore, for example, as compared with an aspect in which the rotation of the piston 13 about the axis is restricted by the non-inclined restriction surfaces, a part of the driving torque of the rotating member 18 is consumed as energy for the separation movement, and the electric motor 19 and the load applied to the drive mechanism 20 are reduced accordingly. Therefore, durability of the electric motor 19 and the drive mechanism 20 can be improved.

In addition, for example, if the driving of the rotating member 18 is further continued and the friction pad 15 and the piston 13 are further separated in the direction of the axis L so that the engagement between the concave portion 13a and the convex portion 15b is released, the electric motor is thereafter driven. The load on the motor 19 and the drive mechanism 20 is further reduced. In the present invention, such an effect can be obtained with a simple configuration in which the regulating surface 13a2 of the recess 13a is formed to be inclined.

Further, in the present embodiment, during the forward rotation drive, that is, when the propelling member 16 is moved directly to the disk rotor 14 side, the regulating surface 13a1 on the side that regulates the rotation of the piston 13 in the same direction as the rotating direction of the rotating member 16. 15b1 was formed so as not to be inclined so as to extend in parallel with the axis L. Therefore, for example, unlike the aspect in which one of the restriction surfaces 13a1 and 15b1 is inclined, the piston 13 is rotated during braking by driving the propulsion member 16, and the friction pad 15 is moved to the disk rotor 14 by the inclined restriction surface. The phenomenon that the braking force is fluctuated (increased) by being pushed out to the side does not occur.

Furthermore, in the present embodiment, the inclined regulating surface is provided only on the piston 13 of the friction pad 15 and the stone 13. According to this, since it is not necessary to make the friction pad 15 that is a consumable part into a shape that is inclined only on one of the regulation surfaces 15b1 and 15b2 facing the circumferential direction, it is possible to make it, for example, a symmetrical shape. . Accordingly, since the left and right common friction pads can be supplied, there is no need to consider the difference between the left and right in the distribution or replacement work, and the handling becomes easy.

In addition, the said embodiment can also be implemented as the following forms which changed this suitably, for example.
That is, as shown in FIG. 3, only the regulation surface 15 b 2 of the convex portion 15 b among the regulation surfaces 13 a 2 and 15 b 2 may be inclined as described above.

Further, unlike each of the above examples, a convex portion may be provided on the piston 13 and a concave portion may be provided on the friction pad 15 to constitute the concave and convex engaging portion. In this case, for example, as shown in FIG. 4, the protrusion 13b is provided on the piston 13 and the recess 15c is provided on the back plate 15a. Only the surfaces 13b1 and 15c1 on the side that restricts the rotation of the piston 13 in the same direction as the rotation direction (only the surface 15c1 in the example of FIG. 4), the rotation of the piston 13 in this direction causes the friction pad 15 and the piston 13 to be axial. The shape is inclined so as to be separated in the L direction.

In addition, regarding the friction pad 15, you may employ | adopt the thing which attached the shim to the surface at the side of the piston 13 of the back plate 15a. In this case, you may provide the notch and hole which can penetrate the convex part of the uneven | corrugated engagement part 22 in a shim.

Claims

A friction pad that abuts against the disk rotor to generate a braking force;
A piston that presses the friction pad toward the disk rotor;
A propulsion member that is linearly movable in the axial direction of the piston to propel the piston toward the disk rotor;
A rotating member coupled to the propelling member via a screw mechanism to move the propelling member linearly;
An electric brake including an electric motor that rotationally drives the rotating member via a drive mechanism,
The propulsion member is disposed so as to be movable relative to the piston in the axial direction and restricted in rotation in the circumferential direction of the piston, and the piston and the friction pad are rotated around the axis of the piston with respect to the friction pad. In the electric brake in which the concavo-convex engaging portion that can be regulated is formed
At least one of the concave portion and the convex portion constituting the concave-convex engaging portion has the above-described thrust member when the propulsion member is directly moved to the anti-disk rotor side among the restriction surfaces for rotation around the axis facing the circumferential direction of the piston. Only on the surface that restricts the rotation of the piston in the same direction as the rotation direction of the rotating member, an inclined surface that separates the friction pad and the piston in the axial direction is formed by the rotation of the piston in this direction. An electric brake characterized by
The electric brake according to claim 1, wherein the inclined surface is applied only to the piston among the friction pad and the piston.
The electric brake according to claim 1, wherein the convex portion is provided on the friction pad, and the concave portion is provided on the piston.