JPH0218829Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a disc brake device that improves the cooling efficiency of the cylinder portion.

[Conventional technology]

A disc brake is operated by supplying fluid pressure to a piston provided in a cylinder of a caliper body, and performs a braking action by frictionally engaging a friction pad with a brake disc that rotates together with a wheel.

However, the frictional heat generated by this frictional braking is transmitted to each member of the brake mechanism, potentially reducing the braking force.For this reason, conventionally, heat insulation treatment has been applied to the back plate of the friction pad and the piston. Prevents heat conduction. However, even if such means are used, satisfactory results cannot always be obtained, so as shown in Japanese Utility Model Publication No. 59-518, the opening edge of a hollow piston that pushes the back plate of the friction pad is At the same time, a notch-shaped air vent is formed in the hollow piston, and a guide member is inserted into the hollow piston in the cylinder axial direction so that its partition wall faces the direction of travel of the vehicle, and the partition wall partitions the bottom side of the inside of the piston. An air passage is formed to communicate with the hollow piston so that air from the direction of movement of the vehicle can be circulated inside the hollow piston to cool the piston and the cylinder. As shown, a vent hole is formed at the opening edge of the hollow piston that pushes the back plate of the friction pad, and a vent hole is formed through the hollow piston and the bottom wall of the cylinder.
A conduit is provided that extends in the axial direction of the cylinder, one end of which is opened into the piston, and the other end is connected to a blower, and when the blower operates, outside air is supplied from the conduit into the piston to cool the piston and cylinder. There is something that I tried to do.

[Problem that the invention attempts to solve]

However, the former structure requires a guide member that fits inside the piston, and the latter structure requires a conduit and a blower, which increases the number of parts and requires assembly. The attachment process becomes complicated.

Therefore, the present invention aims to improve the cooling efficiency of the piston and cylinder portions without increasing the number of parts.

[Means for solving problems]

In order to achieve the above object, the present invention pushes a piston using fluid pressure in a pressure chamber defined in a cylinder of a caliper body, and applies pressure to a brake disc rotating together with a wheel by a pair of friction pads to perform braking. In the disc brake device that operates, a stepped cylinder having a large diameter on the brake disc side and a small diameter on the rear part continuing from the brake disc side through a stepped part and open at both ends is formed in the caliper body parallel to the brake disc axis. Then, a stepped piston having a large diameter on the brake disc side and a small diameter on the rear part thereof and open at both ends is fluid-tightly and movably inserted into the stepped cylinder, and the stepped piston is fluid-tightly and movably inserted into the stepped cylinder. It is characterized in that a pressure chamber is defined between the stepped portion of the cylinder and the stepped portion of the stepped piston.

[Effect]

By configuring as described above, air can be caused to flow in from the small diameter side opening of the piston.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

The carrier body 1 has an actuating part 3 and a counteracting part 4 integrally formed on both sides of a bridge part 2, and straddles a disk 5 which rotates together with the wheel by the bridge part 2, and has an actuating part 3 and a counteracting part 4 on both sides. Section 4 is arranged.

The actuating section 3 has a large diameter section 6a on the disk 5 side.
A stepped cylinder 6 is formed in which a small diameter part 6b is formed in a stepped manner through a stepped part 6c in the rear part following this, and an end 6d on the disk 5 side and an end 6e on the small diameter part 6b side are open. The stepped cylinder 6 has a large diameter part 7a in front on the disk 5 side and a small diameter part 7c in the rear via a stepped part 7b. A stepped piston 7 having an open end 7e on the side 7c is fitted in a fluid-tight and movable manner.

A seal groove 8 is provided around the large diameter portion 6a of the stepped cylinder 6, and a piston seal 9 is provided in the seal groove 8.
A seal groove 10 is provided around the small diameter portion 7c of the stepped piston, a piston seal 11 is fitted into the seal groove 10, and a hydraulic pressure supply port 12 is provided near the stepped portion 6c of the stepped cylinder 6. is opened and this hydraulic pressure is supplied to operate the stepped piston 7, thereby causing the gap between the piston seals 9 and 11, that is, the stepped cylinder 6
A hydraulic chamber 13 is defined by the large diameter portion 6a and stepped portion 6c of the stepped piston 7 and the stepped portion 7b and small diameter portion 7c of the stepped piston 7.

Further, on both sides of the disk 5, friction pads 15, 15 fixed to a pair of pad back plates 14, 14 are arranged, and the upper parts of the pad back plates 14, 14 are connected to the actuating part 3 at the lower part of the bridge part 3. Reaction part 4
The disc 5 is suspended by a pair of hanger pins 16 horizontally suspended between the disc 5 so as to be movable in the axial direction of the disc. It is being pushed toward the center.

Next, to explain the operation of the disc brake configured in this way, when the hydraulic fluid is supplied from the hydraulic pressure supply port 12 to the hydraulic pressure chamber 13 during braking, the stepped piston 7 moves toward the disc 5, and the friction is increased. The pads 15, 15 clamp the disk 5 to perform a braking action, but at this time, the piston seal 9 on the large diameter side of the stepped cylinder 6 deforms toward the disk 5, and the piston on the small diameter side of the stepped piston 7 deforms. The seal 11 deforms in the opposite direction to the piston seal 9, but the piston seal 9 is moved into the seal groove 8 of the stepped cylinder 6.
Since the piston seals 11 are fitted into the seal grooves 10 of the stepped piston 7, when the brake is released, the rollback forces of both piston seals 9 and 11 are in the direction of arrow A in FIG. 2 and arrow B in FIG. 3, respectively. As shown, they act in the same direction to roll back the stepped piston 7.

Frictional heat is generated by the repetition of this braking action and is transmitted to the stepped piston 7 and the stepped cylinder 6, but since the small diameter portion 7c side end 7e of the stepped piston 7 is open, the stepped piston 7 It is possible to cool the piston 7 and the stepped cylinder 6 to suppress an increase in the temperature of the working fluid, and it is also possible to improve the durability of the rubber members such as the piston seals 9 and 11.

FIG. 4 shows an embodiment in which the present invention is applied to a multi-disc brake, in which two brake discs 21 and 22 are provided on a rotating shaft 20 so as to rotate integrally with the rotating shaft 20 and to be movable in the axial direction. , rotation axis 2
A carrier body 24 is disposed on the outer periphery of the vehicle 0. The carrier body 24 rotatably supports the rotary shaft 20 via a bearing 23 and covers the brake discs 21 and 22.

The caliper body 24 is composed of a cylinder part 25 and a reaction force receiving part 26, and the cylinder part 25 has a large diameter part 27a on the brake disc 21 side and a small diameter part 27b in the rear part following this through a step part 27c. A stepped cylinder 27 is formed in a step-like manner and has a large diameter portion 27a opened at the disk 21 side and a small diameter portion 27b at the bottom. A small diameter part 28c is formed through a stepped part 28b in the deep part continuing from the large diameter part 2.
A stepped piston 28, which is open at the disk 21 side of 8a and at the end of the small diameter portion 28c, is fitted in a fluid-tight and movable manner.

A seal groove 29 is provided around the large diameter portion 27a of the stepped cylinder 27, a piston seal 30 is fitted into the seal groove 29, and a seal groove 31 is provided around the small diameter portion 28c of the stepped piston 28. A piston seal 32 is fitted into this seal groove 31.
Further, a pressure fluid supply port 33 is interposed near the step portion 27c of the stepped cylinder 27, and hydraulic fluid is supplied to this pressure fluid supply port 33 from a pressure fluid supply device (not shown), so that the stepped piston 28 , thereby causing the gap between the piston seals 30 and 32, that is, the stepped portion 2
7c, the small diameter portion 28c of the stepped piston 28, and the stepped portion 28b define a hydraulic pressure chamber 34.

A plurality of guide pins 35 are horizontally suspended between the cylinder portion 25 and the reaction force receiving portion 26 of the carrier body 24, and donut-shaped 3 are attached to these guide pins 35.
Pad back plates 36, 37, and 38 are supported movably in the axial direction of the rotating shaft 20.

A donut-shaped friction pad 39 is provided on these pad back plates 36, 37, and 38 for the brake disc 2.
Pad back plate 3 arranged on the cylinder part 25 side of 1
6, on both sides of the pad back plate 37 placed between the disks 21 and 22, and on one side of the pad back plate 38 placed on the reaction force receiving portion 26 side of the disk 22. has been done.

Next, the operation of the multi-disc brake configured as described above will be explained. When the hydraulic fluid is supplied from the compressed supply port 33 to the hydraulic pressure chamber 34 during movement, the stepped piston 28 pushes the pad back plate 36 and reacts. The brake disc 2 is moved toward the force receiving part 26 side, and the friction pads 39 are fixed to the pad back plates 36, 37, and 38 between the reaction force receiving part 26 and the brake disc 2.
1 and 22 for braking action, and when the braking is released, the piston seals 30 and 22 are pressed as in the previous embodiment.
32 rolls back the stepped piston 28.

Since both ends of the stepped piston 28 are open, air flows from the small diameter portion 28c side of the stepped piston 28 to prevent frictional heat generated due to this braking action. cylinder 2
6, friction pad 39 and brake disc 21,
22 can be cooled.

[Effect of idea]

As mentioned above, the present invention performs a braking action by pushing a piston using fluid pressure in a pressure chamber defined in a cylinder of a caliper body, and clamping a brake disc, which rotates together with a wheel, between a pair of friction pads. In the disc brake device, a stepped cylinder having a large diameter on the brake disc side and a small diameter on the rear part adjacent to the brake disc side through a stepped part and open at both ends is formed in the caliper body parallel to the brake disc axis, and A stepped piston, which has a large diameter on the brake disc side and a small diameter on the rear part that follows it through a step, and is open at both ends, is fitted into the stepped cylinder in a fluid-tight and movable manner. Since a pressure chamber is defined between the part and the stepped part of the stepped piston, the piston and cylinder part can be reliably and efficiently cooled by the inflow of air from the small diameter opening part of the piston, and it is possible to cool the piston and the cylinder part reliably and efficiently. Since there is no need to provide separate members such as guide plates and conduits, the number of parts can be reduced and costs can be reduced accordingly.Furthermore, since no complicated assembly process is required, assembly is easy.

[Brief explanation of the drawing]

1 to 3 show an embodiment of the present invention, and FIG. 1 is a cross-sectional front view of a disc brake;
2 and 3 are cross-sectional views showing the operating state of the piston seal, and FIG. 4 is a cross-sectional front view showing an embodiment in which the present invention is applied to a multi-disc brake. 1... Caliper body, 5... Brake disk, 6... Stepped cylinder, 6a... Large diameter section, 6b
...Small diameter part, 6c...Stepped part, 6d...Large diameter side end, 6e...Small diameter side end, 7...Stepped piston, 7a...Large diameter part, 7b...Stepped part, 7c... Small diameter part, 7d... Large diameter part side end, 7e... Small diameter part side end, 8, 10... Seal groove, 9, 11... Piston seal, 13... Hydraulic pressure chamber, 15... ...Friction pad, 20... Rotating shaft, 21, 22... Brake disk, 24... Caliper body, 27... Stepped cylinder, 27a... Large diameter part, 27b... Small diameter part, 27c... Step part, 28 ...Stepped piston, 2
8a...Large diameter part, 28b...Step part, 28c...Small diameter part, 29, 31...Seal groove, 30, 32...Piston seal, 39...Friction pad.

Claims (1)

[Scope of utility model registration request] In a disc brake device in which a piston is pushed by fluid pressure in a pressure chamber defined in a cylinder of a caliper body, and a brake disc that rotates together with a wheel is clamped by a pair of friction pads to perform a braking action, the brake disc A stepped cylinder having a large diameter on the side and a small diameter on the rear part thereof and open at both ends parallel to the brake disc axis is formed in the carrier body parallel to the brake disc axis, and the brake disc side has a large diameter; A stepped piston having a smaller diameter at the rear and open ends at both ends is fitted into the stepped cylinder in a fluid-tight and movable manner, and the stepped piston is connected to the stepped piston. A disc brake device characterized in that a pressure chamber is defined between the two parts.