JP2005291337A - Disc brake - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve mountability to a vehicle in a hydraulic disc brake with a parking brake by eliminating a control cable.
Fluid pressure is supplied from a master cylinder to a fluid pressure chamber 13, a piston 8 is advanced, and brake pads 3 and 4 are pressed against a disk rotor 2 to generate a braking force. At this time, following the wear of the brake pads 3 and 4, the pad wear adjusting mechanism 14 is extended to maintain the contact state with the piston 11 and the pressing piston 22. When the parking brake is operated, the motor unit 26 is energized by the conductive wire 30, and the screw member 25 is rotated and moved forward by the rotation of the rotating shaft 29, and the piston 11 is moved via the steel ball 24, the pressing piston 22 and the pad wear adjusting mechanism 14. And the brake pads 3 and 4 are pressed against the disc rotor 2. By using the lead wire 30 having excellent flexibility, the mounting property on the vehicle can be improved.
[Selection] Figure 1

Description

  The present invention relates to a disc brake that can maintain a braking state regardless of hydraulic pressure and can be used as a parking brake.

Conventionally, as a hydraulic disc brake mounted on a vehicle such as an automobile, one having a parking brake mechanism is known, as described in Patent Documents 1 and 2, for example. The hydraulic disc brake with a parking brake mechanism described in Patent Documents 1 and 2 can be mechanically actuated by a control cable (steel wire), which is usually operated by hydraulic pressure and presses a brake pad against the disc rotor. It is what I did. Accordingly, by operating the parking brake lever or the like and operating the piston via the control cable, a braking force can be generated regardless of the hydraulic pressure, and the braking state can be maintained.
Registered Utility Model No. 2571069 JP-A-7-54886

  However, in the conventional hydraulic disc brake with a parking brake mechanism, the control cable (steel wire) for transmitting the operation force of the parking brake lever or the like to the piston is poor in flexibility and difficult to handle. There is a problem that the mounting property on the vehicle is bad.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a hydraulic disc brake with a parking brake mechanism that is excellent in mountability on a vehicle, without requiring a control cable.

In order to solve the above-mentioned problem, the invention according to claim 1 is characterized in that a pair of pads arranged on both sides via a disk and a piston are slidably fitted to a bottomed cylindrical cylinder and hydraulic pressure is applied. A caliper that slides the piston by a hydraulic pressure supply from a source to bring the pair of pads into contact with the disk, a pressing mechanism that is disposed outside the cylinder and generates a pressing force in the sliding direction of the piston, and the cylinder A push rod that is disposed inside and moved by being pressed by the pressing mechanism, and is disposed within the cylinder, is screwed into one end side of the push rod, contacts the piston, and is pressed by the push rod. In a disc brake comprising a clutch member that presses the piston,
The pressing mechanism includes an electric actuator, and the electric actuator is driven simultaneously with or after a predetermined hydraulic pressure is supplied from the hydraulic pressure source.
According to a second aspect of the present invention, there is provided a disc brake according to the first aspect, wherein the electric actuator is a rotary motor, and a rotary / linear motion converting member is interposed between the rotary motor and the push rod. It is characterized by.

According to the disc brake of the first aspect of the present invention, the piston can be operated by the electric actuator, so that the conventional control cable is not required and the mounting property to the vehicle can be improved.
According to the disc brake of the invention of claim 2, the piston can be operated by pressing the push rod using the rotary motor.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
As shown in FIGS. 1 and 2, the disc brake 1 according to the present embodiment is a caliper floating type hydraulic disc brake, and is disposed on both sides of a disc rotor 2 (disc) that rotates together with wheels (not shown). A pair of brake pads 3 and 4 (pads), a caliper 5 that straddles the disc rotor 2, and a carrier 6 that is fixed to a non-rotating portion of the vehicle and supports the brake pads 3 and 4 and the caliper 5 movably. I have.

  In the caliper 5, a cylinder 8 that faces the back metal 7 of one brake pad 3 is formed, and a claw portion 10 that straddles the disk rotor 2 and contacts the back metal 9 of the other brake pad 4 is formed. A bottomed cylindrical piston 11 is slidably fitted to the cylinder 8 via a fallback seal 12, and the bottom of the piston 11 is in contact with the back metal 7 of the brake pad 3. A hydraulic chamber 13 is formed inside the cylinder 8 and the piston 11, and a pad wear adjusting mechanism 14 is provided inside the hydraulic chamber 13. A master cylinder (not shown) that is a hydraulic pressure source is connected to the hydraulic chamber 13.

  The pad wear adjusting mechanism 14 includes an adjusting nut 15 (clutch member) and an adjusting screw 16 (push rod). The adjustment nut 15 is rotatably fitted in the piston 11 and has a friction surface 17 that frictionally engages the piston 11. The friction surface 17 is pressed against the piston 11 by a disc spring 18 and a thrust washer 19. ing. One end of the adjusting screw 16 is screwed into the adjusting nut 15, and the other end is slidably guided by the cylinder 8, and its rotation around its axis is restricted, and the bottom of the cylinder 8 is controlled by the coil spring 20. It is biased to the side and abuts against a pressing piston 22 (push rod) of a parking brake mechanism 21 (described later).

  The adjustment nut 15 and the adjustment screw 16 are screwed together by a multi-threaded screw, and conversion of rotation and linear motion is mutually possible. Further, as shown in FIG. 3, a predetermined gap C (backlash) is provided in the screw portions of the adjustment nut 15 and the adjustment screw 16, and they are mutually linear by the gap C without relative rotation. It can be moved. The adjustment nut 15 has a larger pressure receiving area with respect to the hydraulic pressure chamber than the adjustment screw 16, and the spring force of the coil spring 20 is larger than the spring force of the disc spring 18.

  The parking brake mechanism 21 includes a guide bore 23 penetrating the bottom of the cylinder 8, a pressing piston 22 inserted into the guide bore 23, a steel ball 24 and a screw member 25, and a motor attached to the outside of the guide bore 23. And a unit 26 (rotary motor, electric actuator, pressing mechanism).

  The pressing piston 22 is slidably and airtightly inserted into the guide bore 23, one end abuts against the stepped portion 27 in the guide bore 23, the movement toward the motor unit 26 is restricted, and the other end The portion is in contact with the adjusting screw 16. The screw member 25 is screwed into a screw portion 28 formed in the guide bore 23 to constitute a rotation / linear motion converting member, and is advanced and retracted along the axial direction of the guide bore 23 by rotation. . The steel ball 24 is interposed between the pressing piston 22 and the screw member 25, and transmits a pressing force without transmitting a rotational force from the screw member 25 to the pressing piston 22. The motor unit 26 has a rotating shaft 29 inserted into the screw member 25 and is slidably coupled to the motor unit 26 so that the screw member 25 is rotated by the rotating shaft 29 and moved forward and backward along the guide bore 23. It has become. In FIG. 1, reference numeral 30 indicates a conducting wire for energizing the motor unit 26.

  Thus, a pressing mechanism that generates a pressing force in the sliding direction of the piston 11 from the outside of the cylinder 8 is configured by the steel ball 24, the screw member 25, the motor unit 25, and the screw portion 28 of the guide bore 23.

Next, the operation of the present embodiment configured as described above will be described.
When hydraulic pressure is supplied from the master cylinder to the hydraulic pressure chamber 13, the piston 11 advances while bending the fallback seal 12, presses one brake pad 3 against the disc rotor 2, and moves the caliper 5 by the reaction force. Then, the other brake pad 4 is pressed against the disc rotor 2 via the claw portion 10. As a result, the disc rotor 2 is sandwiched by the brake pads 3 and 4 to generate a braking force. When the hydraulic pressure from the master cylinder is released, the piston 11 moves back to the original position due to the elasticity of the fallback seal 12, and the braking is released. At this time, if there is no wear on the brake pads 3 and 4, the piston 11 moves forward and backward within the range of the clearance C (see FIG. 3) of the threaded portion between the adjustment nut 15 and the adjustment screw 16. The adjusting mechanism 14 does not operate. FIG. 4 shows the positions of the adjusting nut 15 and the adjusting screw 16 during braking.

  When the brake pads 3 and 4 are worn and the piston 11 moves forward beyond the gap C during braking, a slip occurs between the piston 11 and the fallback seal 12, and the friction surface 17 of the adjusting nut 15 The frictional engagement with the piston 11 is loosened and the adjustment nut 15 rotates, and the pad wear adjustment mechanism 14 extends to maintain the state in contact with the piston 11 and the pressing piston 22. In addition, when a large hydraulic pressure acts on the hydraulic pressure chamber 13 during braking and the piston 11 is displaced beyond the gap C of the screw portion due to the bending of the claw portion 10 or the like, the pressure received by the adjustment nut 15 and the adjustment screw 16 The friction surface 17 of the adjustment screw 15 is pressed against the piston 11 due to the difference in area and the difference in spring force between the disc spring 18 and the coil spring 20, and these friction engagements are maintained, and the adjustment screw 15 does not rotate. Overadjustment of the pad wear adjusting mechanism 14 is prevented.

Next, the operation of the parking brake mechanism 21 will be described.
A driver operates a parking brake switch (not shown) and the like to supply hydraulic pressure to the hydraulic pressure chamber 13 to advance the piston 11, and thereafter or simultaneously, the motor unit 26 is energized by the conducting wire 30 to rotate. The shaft 29 is rotated, whereby the screw member 25 is rotated and moved forward, and the piston 11 is pressed via the steel ball 24, the pressing piston 22 and the pad wear adjusting mechanism 14 to maintain the braking state. Thereafter, even when the energization to the motor unit 26 is stopped, the position of the screw member 25 is held by screwing with the screw portion 28, so that the braking state can be maintained. The braking can be released by rotating the rotating shaft 29 of the motor unit 26 in the reverse direction. At this time, as described above, the pad wear adjustment mechanism 14 extends following the wear of the brake pads 3 and 4 and maintains the contact state with the piston 11 and the pressing piston 22 during braking by hydraulic pressure. Thus, the wear of the brake pads 3 and 4 is compensated.

  At this time, the hydraulic pressure supplied to the hydraulic pressure chamber 13 is generated by, for example, a driver operating a foot brake or using a hydraulic pressure source such as an anti-lock brake system, a traction control system, or a vehicle dynamics control system. be able to.

  Thereby, the conventional control cable (steel wire) becomes unnecessary, and since the conducting wire 30 excellent in flexibility is used instead, the mountability to the vehicle can be improved. Moreover, since the pad wear adjustment mechanism of the existing disc brake mechanism with a parking brake can be used, the reliability is high and the manufacturing cost is not required.

  In the above embodiment, the rotating shaft 29 and the screw member 25 of the motor unit 26 may have a key and key groove coupling structure instead of spline coupling. A thrust bearing can be used instead of the steel ball 24. The motor unit 26 may drive the rotating shaft 29 directly or may be driven via a speed reducer. Further, instead of the motor unit 26 and the screw member 25, it is also possible to directly press the pressing piston 22 by using a self-holding type solenoid actuator that can hold the operating position even when energization is stopped.

1 is a longitudinal sectional view of a disc brake according to an embodiment of the present invention. FIG. 2 is a side view of the disc brake shown in FIG. 1. It is an enlarged view of the thread part of the pad wear adjustment mechanism of the disc brake shown in FIG. It is an enlarged view which shows the position at the time of the braking of the thread part shown in FIG.

Explanation of symbols

1 disc brake, 2 disc rotor (disc), 3, 4 brake pad (pad), 8 cylinder, 11 piston, 15 adjustment nut (clutch member), 16 adjustment screw (push rod), 24 steel ball (pressing mechanism), 25 Screw members (rotation / linear motion conversion member, pressing mechanism), 26 Motor unit (rotation motor, electric actuator, pressing mechanism), 28 Screw portion (rotation / linear motion conversion member, pressing mechanism)

Claims (2)

A pair of pads disposed on both sides of the disc, and a piston is slidably fitted to a bottomed cylindrical cylinder, and the piston is slid by a hydraulic pressure supply from a hydraulic pressure source. A caliper that makes the pad contact the disk, a pressing mechanism that is disposed outside the cylinder and generates a pressing force in the sliding direction of the piston, and a push rod that is disposed inside the cylinder and is moved by being pressed by the pressing mechanism; A disc brake including a clutch member disposed in the cylinder, screwed to one end side of the push rod and abutting on the piston, and pressed by the push rod to press the piston.
The disc brake according to claim 1, wherein the pressing mechanism includes an electric actuator, and the electric actuator is driven simultaneously with or after a predetermined hydraulic pressure is supplied from the hydraulic pressure source. 2. The disc brake according to claim 1, wherein the electric actuator is a rotary motor, and a rotary / linear motion converting member is interposed between the rotary motor and the push rod.

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