JPS6235123A - Disk brake - Google Patents

Abstract

PURPOSE:To prevent the drag and the like caused by a disk at the time of nonbraking by providing a clearance adjusting mechanism for friction materials in those that the friction materials are slidably contacted with the disk by the expansion force of the bag of an elastic body. CONSTITUTION:An actuator 1 is composed of a noncircular cylinder 3, a bag 4 of an elastic body to be inserted therein, and a cap-shaped retainer 5 being covered on the bag 4. On the both sides of the cylinder 3, a clearance adjusting mechanism 10 for friction materials 6, 6' is provided. The clearance adjusting mechanism 10 is provided with a retraction bush 21 which slidably moves on a retractor pin 19 following up the wear of friction materials 6, 6', and a spring 25 which is interposed between the housing 22 of the retraction bush 21 and the sleeve 20 surrounding the retractor pin 19 so as to be compressed at the time of braking.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention applies fluid pressure to an elastic bag inserted into a cylinder of a caliper body, and uses the expansion force of the bag at that time to drive a disc rotor (hereinafter referred to as It relates to a disc brake in which two discs (simply referred to as discs) that are opposed to each other are brought into sliding contact with the disc, and more specifically, a disc brake with an automatic clearance adjustment function for friction materials.

[Technical background]

Traditionally, a combination of a circular cylinder and a hydraulically actuated piston has been used as a disc brake 7 unit that presses the disc from both sides to generate braking force.

However, in disc brakes using such actuators, the pressure receiving surface of the piston is circular, so it is difficult to obtain a large output within the limited radial space of the disc using one piston. As a countermeasure, if several small-diameter pistons are arranged on the same circumference, the circumferential dimension of the caliper body will increase, and the communication path for hydraulic fluid between the cylinders will become complicated, or the number of parts will increase. Problems arise.

Therefore, the present applicant has proposed a technology that can solve these problems through simultaneously filed patents. This technology is the fifth
6 and 6, the actuator 1 is inserted into the cylinder along the inner wall of the non-circular cylinder 3 formed in the caliper body 2, and the open end wall (the flange 4a shown in the figure) is inserted into the cylinder along its inner wall. ) consists of a membrane-like elastic bag 4 that is clamped and held in the deep part of the cylinder across the entire circumference G, and a cup-shaped protective metal retainer 5 that covers the bag. The friction material 6 is brought into sliding contact with the disk D by the expansion force of the elastic bag 4 due to fluid pressure, and has the following features. The features are: (1) It is possible to increase the pressure receiving area and increase the braking force within a limited space, which eases the restriction on the space for incorporating the brake.

(2) It is easy to mold a bag made of elastic material, and the material cost is lower than that of a piston.

(3) When using a piston, there is no need for precision machining of the sliding surface, and the cast cylinder can be used as is.

(4) Since the desired output can be secured without increasing the number of cylinders, there is no need to process a working fluid pressure communication path and the number of parts can be reduced.

[Problem of this invention]

However, in the case of a disc brake G employing this actuator, if one attempts to retreat the friction material from the disc end surface by relying solely on the contraction of the bag 4 during pressure release to secure the necessary gap between the friction materials when not braking. Securing a stable gap cannot be guaranteed due to changes in the elongation rate of the bag due to wear of the lining and due to fatigue.

The object of this invention is to solve this problem.

[Means to solve the problem]

In order to alleviate the above-mentioned problems, the present invention provides a disc brake equipped with the above-mentioned actuator, which is composed of a non-circular cylinder, a membrane-like elastic bag inserted into the cylinder, and a cup-shaped retainer placed over the bag. A retraction plate is interposed between the retainer and the back plate, and a disc axially glued tractor bin is fixed to either one of the caliper body and the retraction plate, surrounding the bin and fixed to the other. a retraction dash that is fitted onto the retractor bin so as to generate appropriate sliding resistance and has one end brought into contact with the member on the sleeve mounting side; A gap adjustment mechanism for the friction material is provided on the retraction side and the retraction side of the disc based on the cylinder, and the gap adjustment mechanism for the friction material consists of a spring that biases the retraction plate in the direction away from the friction material, and is compressed during braking. The restoring force of the spring always pushes back the elastic bag and the retainer placed over it by a certain amount when the pressure is removed. Therefore,
The gap between the friction materials is automatically kept constant, eliminating concerns about disc drag when not braking.

〔Example〕

An example of application of the present invention to a floating type disc brake will be shown based on FIGS. 1 to 4. Since FIG. 5 shows a cross section taken along line A--A in FIG. 2, this figure will also be used for explanation.

The caliper body 2 that straddles the disk D (FIG. 5) consists of a base 2a in which a non-circular cylinder 3 is mounted on one side of the disk, and a cover 2b bolted to the base 2a. 7
8. is a slide provided on the rotation side and rotation side of the disc.
A torque member 10 holds the caliper body slidably in the disk axial direction via 8', and also holds the friction members 6 and 6' facing both sides of the disk so as to slide in the same direction. - A gap adjustment mechanism for friction materials including the traction plate 9.

The cylinder 3, which is a component of the actuator 1 described above, has a rectangular shape as shown in FIG. The diameter portions 3a are continuous. Furthermore, the bag 4 made of the elastic body of the actuator has a flange 4a on the open end side of the circumference M4b along the inner wall of the cylinder 3, and a bottom wall 4c that closes the opening of the cylinder is attached to the opposite end of the circumferential wall. The flange 4a of the bag is inserted deep into the cylinder and is held between the end face of the large diameter portion 3a and the sealing plate 11 pressurized by the cover 2b. The retainer 5 is formed by press-molding a metal plate with a bottom wall 5b interposed between the bag and the back plate 6a of the friction material 6 at one end of the circumference W5a inserted between the bag 4 and the inner wall of the cylinder. This is what I did.

12 is a fluid pressure introduction hole provided in the cover 2b, 13 is a through hole that communicates the hole with the inner chamber of the cylinder, 14 is a groove that communicates with the communication hole 16 to the leader valve 15, and the hole 13 and the groove 14 are Both are provided on the sealing plate 11. 17 is a seal that seals around the communication hole 16 at the joint interface of the cover 2b; 18 is a seal between the cover 2b and the sealing plate 11;
These seals keep the inside of the cylinder 3 sealed, and the fluid pressure introduced there turns the bag 4 into a balloon, creating a disc whose movement is not restricted. It bulges to the side and presses against the friction material.

Next, the gap adjustment mechanism 10, which is a feature of the present invention, will be described. This adjustment mechanism is provided at two locations, one on the insertion side and one on the rotation side of the disk, with the cylinder 3 as a reference. The two adjustment mechanisms have the same configuration, as shown in FIG. a bottle 19; a sleeve 20 surrounding the bottle 19 by fixing the plate 9 to one end thereof; and a sleeve 20 that is fitted around the tip of the bottle 19 so as to generate a sliding resistance slightly greater than the biasing pressure of the retractor spring described later. It is suspended between a retraction push 21 that brings the retraction push 21 into contact with the plate 9, a housing 22 that covers the push, and a seat plate 24 that is supported by a snap ring 23 on the inner surface of the sleeve 20 at a position ΔX away from the housing. A seat plate 2 consisting of a tractor spring 25 and following the plate 9 during braking.
4 comes into contact with the housing 22 as shown in FIG. 4, and slides the pusher 21 against the bottle 19 by an amount equivalent to the wear amount of the lining 6bs6b'.
The friction material is automatically separated from the disk by X (FIG. 1). In the case of a floating disc brake, Δx is the sum of the distances of the pair of friction materials 6,6' from the disc, and the gap between each friction material and the disc is maintained at /2.

In this invention, two actuators are arranged on both sides of the disk, the opposing friction materials are individually determined to be equal to the gap between each actuator and the disk, and two gap adjustment BWt10 are provided on each side of the disk.

Further, the retractor pin 19 of the gap adjustment mechanism 10 may be fixed to the plate 9, but in order to secure the gap ΔX, it is necessary to fix this bin with high precision. In order to stabilize the clipping force, both engaging parts must have a waterproof structure. Therefore, the bottle 19 has a bulged head 19a as shown in the figure, and since this head serves as the quantity reference for the base B2a and the cover 2b, it is possible to minimize the accumulation error during processing. Moreover, by applying a liquid sealant around the head 19a and encircling the outer periphery of the sleeve 20 with a sealant 26, airtightness can be easily ensured. Besides, pin 19
It is also easy to replace when it wears out.

Next, the slide portion 8.8' will be explained.

In a floating disc brake, this sliding part is pressed by one IIY friction material adding actuator, and the other friction material is pressed by the outer claw of the caliper, which is moved by the reaction force of the other friction material. Since it is necessary to move the caliper body toward the actuator side for transmission and absorbing wear of the lining, a well-known groove structure may be used as a movement guide. The figure shows both the configuration shown in FIG.
Either the rubber bottle boots 29G incorporated in the slide pin can be slidably inserted, or one can have the configuration shown in Figure 3, and the other can be directly inserted into the hole of the torque member on the stem of the slide pin, with boots at both ends. It is configured to include a guide sleeve that is sealed.

Reference numeral 30 indicates a guide groove for the friction material 6,6' provided in the torque member, and 31 indicates a torque receiver 1m with which the side surface of the back plate of the friction material comes into contact.

〔effect〕

As stated above, this invention effectively utilizes limited space by using an actuator that combines a non-circular cylinder, an elastic bag inserted into the cylinder, and a cup-shaped retainer that covers the bag. Compared to disc brakes with increased braking force, IJ l-
A gap adjustment mechanism comprising a retraction push that slides on the retractor pin and a spring that is interposed between the housing and the sleeve that surrounds the retractor pin and is compressed during braking is connected to the retraction side of the disk by passing the cylinder as a reference G. Since it is provided on the retraction side, the above-mentioned gap adjustment mechanism solves the problem of poor returnability of the friction material, which is a concern with the brake, and guarantees that a constant gap of the friction material is always maintained.

In addition, a bulging head is formed at one end of the retractor pin,
The head is sandwiched between the base of the caliper body and the cover bolted to it, which minimizes machining errors, making it possible to secure a good gap and easily ensure airtightness. Moreover, there is an advantage that the retractor pin can be easily replaced.

[Brief explanation of the drawing]

Fig. 1 is a plan view showing an example of the disc brake of the present invention with main parts cut away, Fig. 2 is a front view showing a partially cutaway view, and Fig. 3 is taken along the line B-B in Fig. 2. 4 is a sectional view of the gap adjustment mechanism during braking, FIG. 5 is a sectional view taken along line A-A in FIG. It is a sectional view cut and shown. 1... Actuator, 2... Caliper body, 2a
...Base, 2b...Cover, 3...Non-circular cylinder, 4...Elastic body bag, 5...Staker, 6.6
'...Friction material, 7... Torque member, 8.8'...
・Caliper slide part, 9... Retraction plate, 10... 9 Gap adjustment mechanism, 11... Sealing plate, 19
...Retractor pin, 20...Sleeve, 21...
・Retraction push, 22...Housing, 2
4... Seat plate, 25... Retractor spring Fig. 5 Fig. 6 44a

Claims (2)

[Claims] (1) A friction material that will be in sliding contact with the disc rotor is inserted into the non-circular cylinder formed on the caliper body and along its inner wall, and the friction material is inserted into the cylinder along the inner wall of the cylinder, and the friction material is inserted into the cylinder along the inner wall of the cylinder. A bag made of a film-like elastic material is held in a deep place, and a peripheral wall is inserted between the bag and the inner wall of the cylinder.
In a disc brake that generates braking force by pushing forward a bottom wall connected to a peripheral wall by a fluid-pressure operated actuator comprising a cup-shaped retainer interposed between a back plate of a friction material, the retainer and the back plate are a retractor pin in the disk axial direction fixed to either one of the caliper body or the retraction plate; a sleeve surrounding the pin and fixed to the other; A friction material consisting of a retraction push that is externally fitted with appropriate sliding resistance, and a spring that is interposed between the housing placed over the push and the sleeve to bias the retraction plate in a direction away from the friction material. A disc brake characterized in that a gap adjustment mechanism is provided on an input side and an output side of a disc rotor with respect to the cylinder. (2) A bulging head is formed at one end of the retractor pin, and the head is sandwiched between a caliper body and a cover detachably attached to the body to fix the retractor pin to the caliper body. A disc brake according to claim (1), characterized in that: