JPH08244580A - In-calliper incorporating type electric brake device - Google Patents

Abstract

PURPOSE: To provide an electric brake device which contains minute feeding mechanism of large load in a wheel cylinder formed AT a brake calliper. CONSTITUTION: When a brake pedal BP is depressed, an electron control device is operated by the signal from a leg-power switch S1, a motor 15 is driven to rotate a rotary member 14, and a primary piston 8 is pressed to the left side in the figure, through a rod 12 installed eccentrically between the primary piston 8 and the rotary member 14. By the movement of the primary piston 8, a piston 4 moves to the left side in the figure through the liquid in a liquid chamber 7, so as to carry out the braking operation. When the brake pedal BP is released, the motor 15 is rotated reversely, the rod 12 moves in the direction to release the thrust, the primary piston 8 is restored to the original position by a return spring 9, and the brake is released.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric brake device, and more particularly to a compact and lightweight electric brake device having a built-in micro-feed mechanism for large loads.

[0002]

2. Description of the Related Art In recent years, an electric brake device (so-called by-wire system) for operating a brake by an electric signal has been developed in addition to a hydraulic brake operation circuit. The electric brake device converts the pedal force of the brake pedal into an electric signal and operates the brake device by the signal from the electronic control device, so the entire system can be made lighter and smaller than the conventional hydraulic circuit type brake device. It is characterized in that it has an advantage that the system can be easily constructed to execute various controls of the brake device (anti-skid control, traction control, automatic brake control, etc.).

In addition to the above-mentioned development trend, a brake device using a piezoelectric element as a brake device is being developed. As a brake device using a piezoelectric element, the one described in JP-A-61-166759 is known. The brake device described in the above publication controls the brake by changing the braking force according to the voltage applied to the piezoelectric element, and can be expected to be effective in simplifying the structure of the brake device and promoting reduction in size and weight. However, in the brake device using the piezoelectric element, since it is difficult to obtain a large amount of displacement of the piezoelectric element itself, it is necessary to provide a displacement magnifying mechanism that obtains a large amount of movement of the brake piston in addition to the piezoelectric element, There are problems that the structure is complicated, the manufacturing cost is high, and it is difficult to generate a large load with the minute feed mechanism.

[0004]

SUMMARY OF THE INVENTION Therefore, the present invention provides an electric brake device having a large load minute feed mechanism built into a wheel cylinder formed in a brake caliper, and a low-cost auto adjuster for the electric brake device. The purpose of this invention is to solve the above-mentioned problems by adopting a mechanism so that pads can be easily replaced.

[0005]

For this reason, in the caliper built-in type electric brake device of the present invention, a wheel cylinder 5 formed in the caliper 1 of the brake device and a slidable body arranged in the wheel cylinder 5 are slidable. A piston 4, a primary piston 8 arranged in the piston 4, a rotating member 14 arranged to oppose the primary piston 8, a rod 12 eccentrically arranged to the primary piston 8 and the rotating member 14, A motor 15 for driving the rotating member 14, the motor 15 is driven to rotate the rotating member, and the primary piston 8 and the piston 4 are pressed via the rod 12 to perform the brake operation. This is the means for solving the problem.

[0006]

[Function] When the brake pedal BP is depressed, the pedal effort switch S
The electronic control unit is activated by the signal from the motor 1, and the motor 15
Is driven to rotate the rotating member 14, and pushes the primary piston 8 leftward in FIG. 1 via the rod 12 eccentrically mounted between the primary piston 8 and the rotating member. The movement of the primary piston 8 causes the piston 4 to move to the left in the drawing via the liquid in the liquid chamber 7 to perform the brake operation. When the brake pedal is released, the motor rotates in the reverse direction, the rod 12 moves in the direction of loosening the thrust, the primary piston 8 is returned to the initial position by the return spring 9, and the brake is released.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. 1 is a partial cross-sectional view of an electric brake device according to an embodiment of the present invention, FIG. 2 is a cross-sectional view taken along the line AA in FIG. 1, and FIG. 3 is an enlarged cross-sectional view of a main part of an auto-adjuster mechanism. 1 and 2, BP is a brake pedal, S1 is a pedaling force sensor,
The ECU is an electronic control unit, 1 is a caliper in the brake device, 2 is a disc pad, 3 is a disc, and 4 is a piston for holding the disc pad 2 on one side. The description of the detailed configuration of is omitted.

A wheel cylinder 5 is formed in the caliper 1, and a piston 4 is slidably arranged in the wheel cylinder 5.
A seal member 18 is provided between and. The piston 4 is formed in a cylindrical shape with one end closed, one of the disc pads 2 is attached to the outer surface of the one end, and a pressing force is applied between the disc pad 2 and the piston 4. A sensor S2 is provided. The pressing force sensor S2 controls the brake pressure in a manner described later.
A holding member 6 fixed to the caliper 1 is provided inside the piston 4.
Are fitted together, and a liquid chamber 7 is formed between them. The liquid chamber 7 is filled with a liquid (oil or the like) having a predetermined pressure as described later.

A primary piston 8 is fitted inside the holding member 6 so as to project into the liquid chamber 7 so as to be liquid-tight and slidable. Further, between the primary piston 8 and the holding member 6, the same piston is provided. A return spring 9 for urging the right side of FIG. When the primary piston 8 moves to the left in the drawing against the urging force of the return spring 9 by the pressing mechanism described later, the piston 4 moves to the left in the drawing via the liquid in the liquid chamber 7 and performs the braking action. be able to. In the figure, 10 and 11 are comb-shaped notches formed in the piston 4 and the holding member 6 in order to secure the volume in the liquid chamber.

A rod 12 constituting a pressing mechanism is held in contact with the center of the primary piston 8 on the side opposite to the liquid chamber 7, and the other end of the rod 12 serves as the central axis of the primary piston 8. It is held in contact with a rotating member 14 which is rotatably supported by an eccentric shaft 13. The contact position between the rotating member 14 and the rod 12 is provided at a position deviated (eccentric) from the center of the rotating member 14, and the shaft 13 of the rotating member 14 is connected to the output shaft of the motor 15.

Therefore, when the rotating member 14 is rotated by the driving of the motor 15, the primary piston 8 resists the urging force of the return spring 9 through the rod 12 eccentrically mounted between the primary piston 8 and the rotating member. Then, the piston 4 can be moved to the left in FIG. 1, and the piston 4 can be moved to the left in the drawing via the liquid in the liquid chamber 7 to perform the brake operation. A spacer 16 and a thrust bearing 17 are interposed between the rotating member 14 and the motor 15 so as to resist the thrust force at the time of braking, and the motor 15 is attached to the caliper 1 by means such as bolts. It is fixed.

The liquid chamber 7 is connected via a flow path 19 to an auto adjuster mechanism 20 for coping with pad wear (see FIGS. 2 and 3). The auto adjuster mechanism 20
A spring 25, a ball 22, a valve seat 23, an operating member 24, and a reservoir 25 for supplying a fluid to the liquid chamber 7,
In this embodiment, the reservoir 25 is a bellows type flexible member 26.
The reservoir 25 is filled with a fluid having a predetermined pressure. The reservoir 25 is not limited to this embodiment, and various forms such as a well-known structure including a spring and a piston can be adopted. Reference numeral 29 in the figure denotes a spring for urging the operating member.

The automatic adjuster mechanism is normally equipped with the spring 2
Although the ball 22 is brought into contact with the valve seat 23 by 1 to cut off the communication between the flow path 19 and the reservoir 25, when the pad is worn out, the clearance is automatically adjusted in the following manner. That is, when the pad wears, the piston 4 moves to the left in FIG. 1 to exceed the elastic deformation amount of the seal member 18 interposed between the pad 4 and the wheel cylinder 5 to perform a braking action. After that, when the brake is released, the piston 4 moves to the seal member 18
Since the primary piston 8 returns to the initial position, the volume of the liquid chamber 7 increases and the liquid pressure in the liquid chamber 7 decreases. As a result, the ball 22 separates from the valve seat 23 against the urging force of the spring 21 by the hydraulic pressure in the reservoir, and the fluid is replenished from the reservoir 25 to the liquid chamber 7 to maintain the liquid chamber 7 at a predetermined hydraulic pressure. In this way, the pad gap adjustment is automatically performed.

Further, in this auto adjuster mechanism, as shown in FIG.
When the operating member 24 is pushed from the outside in the direction of the middle arrow 27 by a hand or the like, the ball 22 is separated from the valve seat 23. Therefore, if the pad is pushed back in the direction of the arrow B in FIG. The fluid in the liquid chamber 7 is returned to the reservoir 25 so that the pad can be returned to the initial position. The signals from the pedal force sensor S1 and the pressing force sensor S2 are transmitted to an electronic control unit (ECU), and the electronic control unit controls the motor based on these signals. In addition, 2 in the figure
Reference numeral 7 is a seal member between the holding member and the primary piston, and 28 is a seal member between the holding member and the caliper.

The operation of the electric brake device having the above structure will be described. Since there is no command from the electronic control unit 3 before the brake is actuated, this brake unit is in the state shown in FIG. When the brake pedal BP is depressed to brake the vehicle, the electronic control unit is actuated by the signal from the pedal effort switch S1, the motor 15 is driven, and the rotary member 1 is driven.
4 rotates and pushes the primary piston 8 leftward in FIG. 1 via the rod 12 which is eccentrically attached between the primary piston 8 and the rotating member. The movement of the primary piston 8 causes the piston 4 to move to the left in the drawing via the liquid in the liquid chamber 7 to perform the brake operation. After that, when the pressing force applied to the disk 6 by the disk pad 5 reaches a predetermined value, the pressing force sensor S2 detects this value and the electronic control unit (E
CU). The electronic control unit 3 stops the operation of the motor 15 based on the signal from the pressing force sensor S2. When the brake pedal is released, the motor rotates in the reverse direction, the rod 12 moves in the direction of loosening the thrust, the primary piston 8 is returned to the initial position by the return spring 9, and the brake is released.

As the pad wears, the piston 4
A seal member 18 interposed between the wheel cylinder 5 and the wheel cylinder 5.
When the brake is released after moving to the left in FIG.
Can recover only the amount of elastic deformation of the seal member 18,
Moreover, since the primary piston 8 returns to the initial position,
The volume of the liquid chamber 7 increases and the liquid pressure in the liquid chamber 7 decreases. As a result, the ball 22 is separated from the valve seat 23 by the hydraulic pressure in the reservoir against the biasing force of the spring 21, and the fluid is replenished from the reservoir 25 to the liquid chamber 7 to keep the liquid chamber 7 at a predetermined hydraulic pressure.
In this way, the gap between the pad and the disk is automatically adjusted. When the pad is replaced, if the operating member 24 of the auto adjuster mechanism 20 is pushed from the outside in the direction of the arrow by a hand or the like, the ball 22 separates from the valve seat 23. When pushed back in the direction of arrow B of
The fluid in the liquid chamber 7 flows back to the reservoir 25 to return the pad to the initial position, and the pad can be easily replaced.

As described above, in the present invention, since the large-load minute feed mechanism is built in the caliper, the simplification of the device,
The size and weight of the device can be reduced. Further, in the present invention, since the braking force can be increased, maintained, or reduced by the control signal from the electronic control unit, the anti-skid control or the traction control can be executed. Further, without using the pressing force sensor, the pressing force applied to the disk 6 by the disk pad 5 from the load applied to the motor can be detected to control the boater.

[0018]

As described in detail above, the present invention can provide a small-sized and lightweight electric brake device because the wheel cylinder formed in the brake caliper has a built-in small load mechanism with a large load. Further, since a low-cost auto adjuster mechanism is adopted for the brake device, it is possible to automatically cope with the wear of the pad and to easily replace the pad. It is possible to achieve excellent operational effects such as.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of an electric brake device as an embodiment according to the present invention.

FIG. 2 is a sectional view taken along line AA in FIG.

FIG. 3 is an enlarged sectional view of the auto adjuster mechanism in FIG.

[Explanation of symbols]

 1 Caliper 2 Pad 3 Disc 4 Piston 5 Wheel Cylinder 6 Holding Member 7 Liquid Chamber 8 Primary Piston 9 Return Spring 10, 11 Notch 12 Rod 13 Shaft 14 Rotating Member 15 Motor 16 Spacer 17 Thrust Bearing 18 Sealing Member 20 Auto Adjuster Mechanism

Claims (3)

[Claims] 1. A wheel cylinder 5 formed in a caliper 1 of a brake device, a slidable piston 4 arranged in the wheel cylinder 5, a primary piston 8 arranged in the piston 4, and a primary piston. A rotary member 14 arranged to face the piston 8, a primary piston 8, a rod 12 eccentrically arranged to the rotary member 14, and a motor 15 for driving the rotary member 14 are provided. An electric brake device incorporated in a caliper, which rotates and presses the primary piston 8 and further the piston 4 via the rod 12 to perform brake operation. 2. A wheel cylinder 5 formed in a caliper 1 of a brake device, a slidable piston 4 arranged in the wheel cylinder 5, and a liquid between the piston 4 arranged in the piston 4. A holding member that forms a chamber, a primary piston 8 that is liquid-tightly and slidably disposed in the holding member and that can project into the liquid chamber, and a rotating member 14 that is disposed so as to oppose the primary piston 8. A primary piston 8 and a rod 12 eccentrically arranged on the rotary member 14 and a motor 15 for driving the rotary member 14 are provided. The motor 15 is driven to rotate the rotary member, and the primary piston 8 is moved through the rod 12. An electric brake device incorporated in a caliper, which moves and further moves a piston 4 through a liquid chamber to perform a brake operation. 3. The caliper according to claim 2, wherein the liquid chamber 7 is in communication with an auto-adjuster mechanism 20 capable of supplying liquid when the liquid pressure in the liquid chamber falls below a predetermined value. Built-in electric brake device