JP2008020014A - Electric brake for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve problems in which responsiveness is deteriorated in a brake mechanism, such as that for rolling stock, which needs to preliminarily ensure a wide gap for avoiding collision between a disk rotor and a pad supported through an impact absorber such as a spring between an axle and a brake device, and a high-output electric motor is needed for ensuring the responsiveness, resulting in increased cost, increased weight and reduced fuel economy, whereas a high-response mechanism is required in the brake device, and the wasted time for contact between the disc rotor and the pad can be reduced more as the gap between the both becomes smaller. <P>SOLUTION: Lateral rotating members inserted to grooves provided on lateral sides of a direct acting mechanism slide along the grooves, whereby each of lateral brake levers with the rotating members as power points is rotated around a fulcrum of a brake lever pad, and lateral braking members as power points rotatably supported by the brake levers hold a member to be braked from both lateral sides of the member to generate a braking force. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a vehicular electric brake that generates a braking force using an electric motor as a power source.

  For example, Japanese Patent Application Laid-Open No. 2000-104766 (hereinafter referred to as Patent Decentralization 1) discloses an electric brake in which an electric motor is used as a power source and a pad is pressed against a disk rotor to obtain a braking force. In this method, rotation by the electric motor is converted into rotation-linear motion by a ball screw, and an excessive braking force is obtained from the rotation torque of the electric motor by a toggle mechanism.

JP 2000-104766 A

  The electric brake device disclosed in Patent Document 1 is a disc brake caliper system, and was devised mainly as a brake device for automobiles. Since the disc brake is a caliper method in which a disc rotor that rotates together with the axle is clamped between the pads on both sides and the brake is applied, the gap between the disc rotor and the pad of the electric brake on the axle is constant and minute.

  A feature of this caliper method is that the gap between the disk rotor and the pad cannot be made large, and at the same time, the smaller the gap is, the shorter the time required for the pad to contact the disk rotor can be shortened and the responsiveness can be improved. . Therefore, in order to avoid collision between the disk rotor and the pad by supporting the axle and the brake mechanism via an impact absorbing material such as a spring, it is necessary to secure a wide gap between the disk rotor and the pad in advance. In the brake mechanism of this type, the responsiveness may be reduced.

  For this reason, in order to ensure responsiveness, a high-output electric motor is required, resulting in high cost, high weight, and reduced fuel consumption.

  An object of the present invention is to provide an electric brake mechanism capable of generating a predetermined braking force with a low-output electric motor and further improving the responsiveness.

  An object of the present invention is to provide a vehicular electric brake including a braked member that rotates with a wheel and a brake member that sandwiches both sides of the braked member. A support portion for rotating and supporting a central portion; and an electric motor attached to the other end of the brake lever. The rotation of the brake motor causes the other end of the brake lever to be spread and the support portion as an axis. This is achieved by the braking member rotating the braked member in the clamping direction.

  Another object of the present invention is to provide a vehicular electric brake including a braked member that rotates with a wheel and a brake member that sandwiches both sides of the braked member. A conversion mechanism that converts the rotation of the linear movement to a linear drive, a linear movement mechanism that moves linearly by the conversion mechanism, a support member that guides the linear movement mechanism in the linear movement direction, a connecting member that connects them, and the linear movement mechanism Rotating member that is slidably supported along left and right grooves provided in the moving mechanism, and left and right brakes that are rotatably supported around a fulcrum provided with the braking member on the opposite side of the rotating member And a brake lever pedestal for supporting the fulcrum of the brake lever and the connecting member, and slides along a groove of a linear motion mechanism that moves forward by a rotation-linear motion conversion mechanism by rotational driving of the electric motor. Rotating member It is achieved by sandwiching the braked member in the left and right braking member opposite the brake lever which rotates about the fulcrum and move to the right.

  Further, the above-mentioned object is that the groove shape of the linear motion mechanism is composed of two or more straight lines or curved shapes that are bilaterally symmetrical and have different angles, and the moving speed of the braking member during the rotation of the electric motor can be varied stepwise. Is achieved.

  Further, the object is to provide a mechanism for converting the rotation of the electric motor into a linear motion and a support member for supporting the connecting member, and a sliding member provided between the fixed members fixed to the brake lever base together with the left and right brake lever fulcrums. This is achieved by being slidably supported only in the axle direction, and correcting the center deviation between the braked member and the brake lever support when a braking force is generated.

  According to the present invention, it is possible to provide an electric brake mechanism capable of generating a predetermined braking force with a low-output electric motor and further improving the responsiveness.

  An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a top view (initial position) of an electric brake for a vehicle provided with a first embodiment of the present invention.
In FIG. 1, a disc rotor 10 that is a disc-shaped brake member is fixed to an axle 2 that connects between left and right wheels 1 attached to a lower portion of a carriage (not shown) on which passengers board. The carriage is mounted on the axle 2 via an impact absorbing material for absorbing an impact during traveling. A brake lever receiving base 20 is fixed to the carriage via an arm-shaped bracket (not shown). The above-mentioned shock absorbing material is intended to make it difficult for vibration generated between the rail and the axle 2 during transmission to be transmitted to the carriage side.

  Brake levers 40a and 40b are connected to the brake lever receiving base 20 via rotary sliding members 210a and 210b. The rotary sliding members 210a and 210b serve as rotational fulcrums for the brake levers 40a and 40b. On the disc rotor 10 side of the brake levers 40a and 40b, brake members 30a and 30b that sandwich the disc rotor 10 from the left and right to generate a braking force are attached. The control members 30 a and 30 b include a friction member that comes into contact with the disk rotor 10. The control members 30a and 30b are connected with the rotation sliding members 200a and 200b serving as rotation fulcrums. Due to the rotating sliding members 200a and 200b, the brake members 30a and 30b serve as action points when a braking force is generated.

  Rotating members 50a and 50b serving as power points when brake force is generated are attached to the brake levers 40a and 40b on the opposite side of the control members 30a and 30b with the rotary sliding members 210a and 210b as a boundary. The brake levers 40a and 40b are rotated about the rotation fulcrums 210a and 210b by pushing the rotating members 50a and 50b to the left and right, and the disc rotor 10 is sandwiched between the left and right control members 30a and 30b to generate a braking force. I will let you.

  An electric motor 130 is used as a brake drive source. The electric motor 130 is fixed to the ball screw bracket 140. A drive portion of the electric motor 130 is fixed to the ball screw 80 via the coupling 120. The rotational driving force of the electric motor 130 is converted by the ball screw 80 into direct drive in the traveling direction orthogonal to the axle 2. A cam mechanism 70 is fixed to a nut flange portion of the ball screw 80 that moves linearly. In this cam mechanism 70, guide guides 90 a and 90 b parallel to the left and right of the ball screw 80 are fixed to the ball screw bracket 140 as guides for direct drive.

Details of the cam mechanism 70 will be described with reference to FIG.
FIG. 2 is a top view of the electric brake for a vehicle provided with the first embodiment of the present invention (when the brake disc rotor is in contact).

In FIG. 2, grooves 60a and 60b are formed in the brake levers 40a and 40b, and the rotating members 50a and 50b of the brake levers 40a and 40b in the grooves 60a and 60b are arranged to slide. When the electric motor 130 is driven to rotate, the ball screw 80 rotates in the direction of arrow A, and the cam mechanism 70 moves linearly along the guide guides 90a and 90b (in the direction of arrow B), along the grooves 60a and 60b of the cam mechanism 70. As the rotating members 50a and 50b move, the rotating members 50a and 50b are pushed and expanded in the direction of arrow D. The brake levers 40a and 40b are moved by the movement of the rotating members 50a and 50b so that the rotating sliding members 210a and
By rotating 210b as a fulcrum (arrow C direction), the control members 30a and 30b move in the direction in which the disk rotor 10 comes into contact (arrow E direction).

  FIG. 3 is a top view of the electric brake for a vehicle equipped with the first embodiment of the present invention (when a braking force is generated).

In FIG. 3, when the electric motor continues to be driven to rotate after the control members 30 a and 30 b contact the disk rotor 10, similarly, the disc rotor 10 is tightened with the control elements 30 a and 30 b to generate a braking force due to a frictional force. . The relationship between the number of rotations of the electric motor 130 driven and the amount of movement of the control members 30a and 30b is determined by the shape of the grooves 60a and 60b of the cam mechanism 70.

As an example, as shown in FIGS. 2 and 3, the grooves 60 a and 60 b provided in the cam mechanism 70 have symmetrical shapes corresponding to the two brake levers 40 a and 40 b. The shape is a two-stage shape of straight lines with different angles, and the first stage is for movement until the control elements 30a, 30b come into contact with the disk rotor 10 at a large angle α1, and the second stage is a control element at a shallow angle α2. 30a,
30b is used for pressing after contact with the disk rotor 10.

  Accordingly, the responsiveness can be improved by changing the groove shape of the cam mechanism 70 before the contact with the disc rotor 10 of the control members 30a and 30b that do not require an excessive braking force and after the contact that requires an excessive braking force. It is possible to improve.

  That is, until the control members 30a and 30b that do not require excessive rotational torque come into contact with the disk rotor 10, the small output electric motor 130 can be achieved even if the reduction ratio of the motor due to the grooves 60a and 60b of the cam mechanism 70 is reduced. Therefore, by driving the brake levers 40a and 40b at high speed, wasted time can be shortened and responsiveness can be improved.

FIGS. 9A and 9B are graphs showing the relationship between time and thrust.
9 (a) and 9 (b), when the groove shape provided in the cam mechanism 70 is one stage, as shown in FIG. 9 (a), the restrictor reaches the “target thrust” from “disc rotor contact”. The thrust R increases in proportion to the time until. On the other hand, when the groove shape has two stages, as shown in FIG. 9 (b), the time taken for the control to reach the “target thrust” from “disc rotor contact” is indicated by a solid line from the position indicated by the broken line. Shortened to position. Here, the groove 60a of the cam mechanism 70,
Although the 60b shape has been described as a straight two-stage shape with different symmetrical angles, it may be a shape composed of two or more straight lines or a shape in which the angle gradually increases with a curve.

  As described above, the reduction ratio of the rotational torque by the electric motor 130 can be varied depending on the moving position of the cam mechanism 70 by the shapes of the grooves 60 a and 60 b provided in the cam mechanism 70. Further, it is possible to sufficiently improve the responsiveness and the braking force of the control members 30a and 30b even with a small output electric motor.

The fail-safe function of the electric brake is a state in which the disc rotor 10 is sandwiched between the control members 30a and 30b and the braking force is generated (the state shown in FIG. 3), but the power supply to the electric motor is stopped. It is necessary to maintain the braking force.

  In the electric brake according to the present invention, since the rotational torque of the electric motor 130 is converted from the rotational motion to the linear motion by the ball screw 80, the lead that advances per ball screw diameter D (shown in FIG. 1) and one rotation of the ball screw. From the length P (shown in FIG. 1), the static friction coefficient μs necessary for the cam mechanism 70, which is the linear motion mechanism of the ball screw 80, to maintain a static state is determined, and if μs> P / (2πD) is satisfied The braking force can be maintained even when the motor power is stopped. Therefore, the diameter D and the lead length P of the ball screw 80 are preferably selected to satisfy the above formula in consideration of the static friction coefficient μs of the ball screw.

  Referring to FIG. 4, a description will be given of a case where the brake is operated with the center of the disc rotor 10 and the brake lever pedestal 20 shifted by ΔS. The ball screw 80 is rotated by the rotation drive of the electric motor 130 which is a main component of the electric brake. Then, the cam mechanism 70 operates and the brake levers 40a and 40b rotate around the rotary sliding members 210a and 210b.

  In FIG. 5, because of the relationship that the center of the cradle 20 is shifted by ΔS, first, the one-side restrictor 30 a comes into contact with the surface of the disk rotor 10. The electric motor 130, the ball screw 80, and the cam mechanism 70 are fixed to a ball screw bracket 140, and are supported by the electric brake bracket 100 so as to be movable only in the axial direction of the axle 2 by sliding members 110a and 110b.

  For this reason, as shown in FIG. 6, when the electric motor continues to rotate, the ball screw bracket 140 supporting the electric motor 130, the ball screw 80, and the cam mechanism 70 moves ΔS to the side of the restrictor 30a. The control member 30b of this is also in contact with the disk rotor 10 to generate a braking force.

Thus, it is possible to generate a braking force even when the disc rotor 10 and the brake lever pedestal 20 are misaligned in the direction of the axle 2. The brake force can be released by returning the electric motor 130 to the initial position by reversely rotating the electric motor 130 by the same number of rotations as in the brake operation.

  Since the electric brake described above can generate an excessive braking force with a small output electric motor, the apparatus can be downsized. In addition, it is possible to improve fuel consumption by reducing the weight with a simple configuration. Furthermore, by using the electric brake bracket 100, it can be fixed to the existing brake lever cradle 20 and has compatibility that allows easy replacement with an existing brake.

Next, the brake lever mounting structure will be described with reference to FIGS.
FIG. 7 is a perspective view for explaining the mounting structure of the brake lever.
FIG. 8 is a perspective view for explaining a state in which a brake lever is attached.
7 and 8, the brake lever receiving base 20 is substantially U-shaped, and a through hole 20a for fixing the brake levers 40a and 40b is attached. The electric brake bracket 100 has substantially the same shape as the brake lever pedestal 20, and a through hole 100a is also provided at the same position as the through hole 20a of the brake lever pedestal. The brake lever base 20 and the electric brake bracket 100 are combined to form an integral structure. The brake levers 40a and 40b are attached to the through holes 20a and 100a, and the rotary sliding members 210a and 210b are inserted into the through holes 20a and 100a to fix the brake levers 40a and 40b.

  An electric brake bracket 100 is coupled to the brake lever cradle 20 together with brake levers 40a and 40b. In this connection, the rotation sliding members 210a and 210b which are the rotation fulcrums of the brake levers 40a and 40b are inserted into the through holes 20a and 100a and connected. The electric brake bracket 100 is mounted with the electric motor 130, the ball screw 80, and the ball screw bracket 140 provided with the cam mechanism 70 described in FIG. The sliding members 110a and 110b shown in FIG. 1 are fixed to the ball screw bracket 140 so as to be slidable only in the axial direction of the axle 2.

  The ball screw bracket 140 supported by the electric brake bracket 100 is configured to be slidable only in the axial direction of the axle 2 with respect to the brake lever base 20. Since the electric brake bracket 100 is fixed to the brake lever pedestal 20, the electric brake can be fixed to the existing brake pedestal 20 as it is.

  As described above, according to the present invention, in an electric brake using an electric motor, an electric brake capable of achieving both contradictory response and excessive braking force can be realized using a small output electric motor. In addition, by using the electric brake bracket 100, it is possible to supply a compatible electric brake that can be mounted on the brake lever receiving base 20 on an existing carriage as it is.

It is a top view of an electric brake provided with one example of the present invention. It is a top view of an electric brake provided with one example of the present invention. It is a top view of an electric brake provided with one example of the present invention. It is a top view of an electric brake provided with one example of the present invention. It is a top view of an electric brake provided with one example of the present invention. It is a top view of an electric brake provided with one example of the present invention. It is a perspective view which shows the attachment structure of a brake lever. It is a perspective view which shows the attachment structure of a brake lever. It is a graph which shows the relationship between time and generated thrust.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Wheel, 2 ... Axle, 10 ... Disc rotor, 20 ... Brake lever cradle, 30a, 30b ... Control wheel, 40a, 40b ... Brake lever, 50a, 50b ... Rotating member, 60a, 60b ... Cam mechanism groove, 70 ... Cam mechanism, 80 ... Ball screw, 90a, 90b ... Guide guide, 100 ... Electric brake bracket, 110a, 110b ... Sliding member, 120 ... Coupling,
130 ... Electric motor, 140 ... Ball screw bracket, 200a, 200b, 210a, 210b ... Rotating sliding member.

Claims (4)

In an electric brake for a vehicle including a braked member that rotates together with a wheel and a brake member that sandwiches both surfaces of the braked member,
A brake having the brake member attached to one end; a support portion for rotating and supporting the central portion of the brake lever; and an electric motor attached to the other end of the brake lever. An electric brake for a vehicle, wherein the other end of the lever is expanded and the braking member rotates in the clamping direction of the braked member with the support portion as an axis. In an electric brake for a vehicle including a braked member that rotates together with a wheel and a brake member that sandwiches both surfaces of the braked member,
An electric motor that is a power source of the braking member, a conversion mechanism that converts the rotation of the electric motor into a linear drive, a linear mechanism that moves linearly by the conversion mechanism, and guides the linear mechanism in the linear direction A supporting member that connects the connecting member, a rotating member that is slidably supported along left and right grooves provided in the linear motion mechanism, and the braking member on the opposite side of the rotating member. Left and right brakes supported rotatably about a fulcrum, and a brake lever support for supporting the fulcrum and the connecting member of the brake lever, and rotating to linear motion conversion by rotating the electric motor. A rotating member that slides along a groove of a linear motion mechanism that moves forward by a mechanism moves to the left and right, and a brake lever that rotates about a fulcrum sandwiches the member to be braked between the left and right braking members. Electric blur for vehicles Key. In the electric brake for vehicles according to claim 1,
The groove shape of the linear motion mechanism is composed of two or more straight lines or curved shapes that are symmetrical and have different angles, and the moving speed of the braking member during the rotation of the electric motor can be varied stepwise. Electric brake. In the electric brake for vehicles according to claim 1,
A mechanism for converting the rotation of the electric motor into a linear motion and a support member for supporting the connecting member are provided with a sliding member, and the left and right brake lever fulcrums are fixed to the brake lever cradle between the fixed members in the axle direction. A vehicular electric brake, wherein the vehicular electric brake is supported so as to be slidable only, and a center shift between the braked member and the brake lever receiving base can be corrected when a braking force is generated.

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