JPS6235122A - Actuator for disk brake - Google Patents

Abstract

PURPOSE:To enable miniaturization by constituting an actuator utilizing an elastic bag and making a cylinder in a noncircular shape so that the pressure receiving area of fluid pressure can be increased to the maximum in a limited space. CONSTITUTION:A caliper body 1 is composed of a base 3 provided with a noncircular cylinder 2 and a cover 4 bolted thereto. An actuator 10 consists of a cylinder 2, a bag 11 of membranous elastic body inserted therein, and a retainer 12 being covered on the outer surface of this bag. Being opened at one end, the bag 11 is held so as to be inserted in the recess of the cylinder all around the periphery. Since the sectional shape of the cylinder can be made in a rectangular form by the adoption of the bag 11, the pressure receiving area of fluid pressure can be increased in a limited space, enabling the miniaturization.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an actuator for a disc brake operated by fluid pressure, and particularly to an actuator that can increase braking force without increasing the size of the brake.

[Conventional technology and its problems]

A disc brake that generates braking force by pressing a disc rotor (hereinafter simply referred to as a disc) from both sides can (1) obtain a braking force proportional to the input. (2)
The centrifugal force of the disc shakes off muddy water, so it has good water recovery properties. (3) There is an advantage that maintenance such as replacement of friction materials is easy.

By the way, the 7-actuator for disc brakes has traditionally been a combination of a circular cylinder and a hydraulically actuated piston, but since this actuator has a circular fluid pressure receiving surface, it can only be used in a limited radial direction. It is difficult to obtain a large output within a space, so conventional disc brakes are replaced with drum brakes on vehicles with narrow assembly space, such as those with small wheels and a part of the steering mechanism built-in. When trying to take advantage of the above advantages by installing a drum brake on a vehicle such as a small forklift truck, due to space limitations, it is necessary to arrange several small-diameter pistons on the same circumference to achieve the required brake. It will secure power. However, when several pistons are assembled into one caliper body, the caliper body becomes thick in the circumferential direction of the disc (which may make it impossible to use a disc brake due to space considerations).

Also, the communication path for hydraulic fluid between cylinders becomes complicated.
The impact on manufacturing costs due to an increase in the number of parts cannot be ignored.

In order to eliminate such problems, the present invention aims to provide an actuator that makes maximum use of the annular space between the wheel and the hub, which can increase braking force without increasing the size of the caliper body. .

[Means for solving problems]

In order to achieve the above object, in the present invention, the cylinder formed in the caliper body is made non-circular.

Further, a bag made of a film-like elastic material with one end open was inserted into the cylinder along the inner wall, and the side wall of the one end of the bag was clamped and held at the inner part of the cylinder over the entire circumference.

Furthermore, the elastic bag Oko is inserted with the peripheral wall at the same number as the inner wall of the cylinder, and a cup-shaped retainer interposed between the bottom excitation connected to the peripheral wall and the back plate of the friction material is placed, and a fluid pressure is applied to the inner surface. The expansion force of the bag receiving the disk is transmitted to the friction material through this retainer, and the force is used to advance the H-mounter so that it comes into sliding contact with the disk.

In the actuator configured as described above, since the cross-sectional shape of the cylinder can be rectangular, the pressure-receiving area of the fluid pressure is larger than that of a circular pressure-receiving surface with equal radial and circumferential dimensions of the disk. , the braking force determined by the pressure receiving area also increases. Therefore, the necessary braking force can be secured without dividing the actuator into a plurality of parts, and space restrictions for assembly are alleviated.

〔Example〕

The attached drawings show an example of application of the present invention to a floating disc brake.

Reference numeral 1 in FIGS. 1 to 3 is a caliper body that straddles the disk D (FIG. 1), and this body consists of a base 3 having a non-circular cylinder 2 on one side of the disk, and a cover 4 bolted to it. Consists of. Reference numeral 5 holds the caliper body slidably in the disk axial direction via slide portions 6.6' provided on the insertion side and the rotation side of the disk, and furthermore, friction materials 7.5 are opposed to both surfaces of the disk. 7' is also a torque member which is slidably held in the same direction, and 8 is a friction material gap adjustment mechanism including a retraction plate 9.

The actuator 10 of the present invention includes the cylinder 2,
It consists of a membrane-like elastic bag 11 inserted into the bag 11 and a retainer 12 placed over the outside of the bag.

The cylinder 2 has a rectangular shape as shown in FIG. 2Q, and a large diameter portion 13 is formed in the inner part of the cylinder 2 so as to pass through to the cover mounting surface of the base.

The bag 11 has one end open, and a flange l is attached to the open end of the peripheral wall 11a along the inner wall of the cylinder 2 as shown in the figure.
lb, and a cup-shaped one with a bottom wall 11c connected to the end opposite to the peripheral wall that closes the opening of the cylinder is desirable.
The flange 11b is held between the end of the large diameter section 13 and a sealing plate 14 which is inserted into the large diameter section and pressurized by the cover 4.

The retainer 12 has a cup shape with a bottom wall 12b connected to one end of a peripheral wall 12a inserted between the bag 11 and the inner wall of the cylinder, and the bottom wall 12b is located between the bag 11 and the back plate 7a of the friction material 7. Cover the bag like this.

This requirement can be met if the retainer is press-formed from a metal plate and has rigidity that does not deform under the pressure of the working fluid.

Reference numeral 15 denotes a fluid pressure introduction hole provided in the cover 4, and this hole communicates with the inner chamber of the cylinder 2 via a through hole 16 provided in a sealing plate 14 that closes one end of the cylinder 2. Further, in order to vent air within the cylinder, the sealing plate 14 is provided with a groove 19 communicating with a communication hole 18 to the bleeder valve 17. Further, a seal 20 surrounding the connecting portion of the communicating hole 18 is provided at the joint interface of the cover 4 to prevent leakage of fluid pressure.
An O-type seal 21 is placed between the cover 4 and the outer periphery of the chamfered rear surface of the sealing plate 14 to seal the cylinder part. When fluid pressure is introduced, the bag 11 becomes a balloon and inflates toward the disk side where movement is not restricted, pressing the friction material.

Next, the friction material gap adjustment mechanism 8 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 2 as a reference. The two adjustment mechanisms have the same configuration, and as shown in FIG. 3, a retraction plate 9 is inserted between the friction material 7 and the retainer 12.
A retractor pin 22 held in the caliper body 1 in the disk axial direction, a sleeve 23 whose one end is fixed to the plate 9 and surrounds the bin 22, and a pressure slightly greater than the biasing pressure of the retractor spring described later at the tip of the bin 22. A retraction bushing 24 that is fitted externally to create a large sliding resistance and has one end abutted against the plate 9, a housing 25 that covers the bushing, and a seat plate 27 that is supported by a snap ring 26 on the inner surface of the sleeve 23. The seat plate 27, which is suspended between the wheels and consists of a tractor spring 28 and follows the plate 9 during braking, comes into contact with the housing 25 and slides the bush against the bin 22 by an amount equivalent to the amount of wear on the linings 7b and 7b'. When pressure is applied, the friction material is automatically separated from the disk by a constant amount x.

△X is the pair of friction materials 7 in the case of a floating disc brake.
．． 7' is the sum of the distances from the disk, and the gap between each friction material and the disk is maintained at ΔX/2. 29
is a sealing material that seals the outer periphery of the sleeve.

In a floating type disc brake, where one friction material is pressed by an actuator and the other friction material is pressed by the outer claw of the caliper moved by the reaction force, the slide portion 6.6' is configured to handle the reaction force on the other friction material. Since it is necessary to move the caliper body toward the actuator side in order to transmit the noise and absorb the amount of wear on the lining, a well-known structure may be used as a movement guide. In the figure, both are configured as shown in FIG. One of them has the configuration shown in FIG. 4, and the other has a guide sleeve on the stem of the slide pin that is directly inserted into the hole of the torque member and sealed at both ends with boots.

Reference numeral 33 indicates a guide groove of the friction material 7, 7' provided in the torque member, and 34 indicates a surface of the torque receiver against which the side surface of the back plate of the friction material comes into contact.

Note that the actuator of this invention is a floating caliper type,
It can be applied to all disc brakes that use fluid pressure as an operating source, regardless of fixed type.

〔effect〕

As described above, according to the present invention, the fluid pressure introduced into the non-circular cylinder is applied to the inner surface of the elastic bag, and the expansion force of the bag is used to slide the friction material against the disk. This makes it possible to maximize the fluid pressure receiving area within a limited space and increase the braking force. In other words, a large output can be obtained with a small disc brake, which eases space restrictions when installing the brake.

In addition, the pressure receiving body (bag) formed of an elastic body is easy to mold, and the material is cheaper than a piston, and the expansion and storage of the pressure receiving body is used to press the friction material. The cast cylinder can be used as is without the need for precision machining of the sliding surface, which is required when using a cylinder, and since there is only one cylinder, there is no need to machining the working fluid pressure communication path, and the number of other parts It is also advantageous in terms of manufacturing and cost of the brake, as less is required.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of an example of a disc brake employing the actuator of the present invention taken along the axial line of the disc, Fig. 2 is a partially cutaway front view, and Fig. 3 is a partially cutaway view. A plan view of the cutaway state, Figure 4 is A of Figure 2.
- It is a sectional view along the A line. 1... Caliper body, 2... Cylinder, 3...
Base, 4... Cover, 5... Torque member, 6.6
'...Slide part, 7.7'...Friction material, 8...
Friction material gap adjustment mechanism, 10... actuator, 1
1... Elastic bag, 12... Retainer, 14...
Sealing plate, 21...0 type seal

Claims (1)

[Claims] A non-circular cylinder formed in the caliper body, and a membrane-like elastic bag that is inserted into the cylinder along its inner wall, and the open edge wall of one end is clamped and held deep inside the cylinder around the entire circumference. and a cup-shaped retainer, the peripheral wall of which is placed over the bag and inserted between the inner wall of the cylinder, and the bottom wall connected to the peripheral wall is interposed between the back plate of the friction material, and the bag is inserted into the cylinder. An actuator for a disc brake configured to receive introduced fluid pressure on its inner surface to press and advance a friction material through a retainer so as to come into sliding contact with a disc rotor.