JPS6111547Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a boot protection structure for a disc brake.

In general, in disc brakes, various measures have been taken to ensure smooth sliding of the piston by sealing the sliding surface between the piston that presses the friction pad against the rotor and the cylinder in which it is housed from the outside air. As one of these methods, a boot is often installed across the outer edge of the cylinder and the outer periphery of the tip of the piston.

By the way, since the boot assembled in this way is assembled to the piston, it faces the sliding surface of the rotor and friction pad, and has a bellows provided on the boot to allow relative movement between the cylinder and the piston. If the piston extends toward the rotor, it may be damaged due to contact with the friction pad or the thermal effect of the sliding contact.To prevent this, a circumferential groove is provided on the outer periphery of the piston to prevent one end of the boot from being damaged. In order to fit into this circumferential groove and suppress the movement of the boot in the axial direction of the cylinder, or to prevent damage to the boot due to heated abrasion powder generated during braking, a protection covering the part of the boot facing the rotor is provided. Assembling is being carried out.

However, in the former case, where one end of the boot is fitted into the piston circumferential groove, the volume of that part is small, resulting in poor assembly workability, and in the latter case, it is difficult to improve the boot assembly work. There was a problem that it was not possible.

From this point of view, the present invention aims to provide a protective structure for the boot that can obtain good assembly workability. In a disc brake in which a dustproof boot is installed over the outer periphery of the tip of the piston to be mated, a protective disc is inserted between the front surface of the piston and the back surface of the friction pad so as to cover the front surface of the piston, and the outer edge of the cylinder. a circumferential protrusion formed on the stepped portion and forming an overlapping covering part in the disk axial direction together with the outer circumference of the protective disk; and a small diameter step formed on the outer circumference of the tip of the piston for assembling the boot end. The protective disc is further provided with a plurality of protrusions arranged intermittently in the circumferential direction on the outer peripheral edge thereof to lock the axial movement of the assembled end of the boot onto the piston. This is a disc brake boot protection structure.

The present invention will be explained below with reference to embodiments shown in the drawings.

In the figure, 1 is a rotor, 2 is a caliper that straddles the edge of the rotor and is arranged to be able to move in the axial direction of the rotor, and 3 is a cylinder formed on one leg 2a of the caliper 2. , 4 is this cylinder 2
5 is a hydraulic chamber; 6 and 7 are friction pads arranged oppositely with the rotor 1 in between; when one of the friction pads 6 is pressed against the rotor 1 by hydraulic action, this The reaction force causes the caliper 2 to move to the right in the figure, forming a reaction part, and the other friction pad 7 is pressed against the rotor 1 by one leg 2b.

8 is a boot having a bellows-shaped trunk 8a;
One end 8b on the large diameter side is fitted into a circumferential groove formed by the inner protrusion 2c of the caliper 2, and one end 8c on the small diameter side is fitted into the stepped small diameter portion 4 of the piston 4.
It is tightly fitted to a.

A protective disc 9 is inserted between the tip of the piston 4 and the back surface of the friction pad 6, and its outer diameter is larger than that of the piston 4. Cut-and-raised protrusions 9a are cut and extended toward the back surface intermittently in the direction. This cut-and-raised protrusion 9a forms the tip stepped small diameter portion 4a of the piston 4.
It is located on the outer periphery of the piston and has an arcuate extending tip so that one end 8c of the boot 8 can be held between the piston small diameter portion 4a and the piston small diameter portion 4a without damaging the boot 8.

In addition, 10 is a piston seal.

According to such a configuration, the boot 8 can be assembled with the piston 4 by simply inserting the one end 8c of the boot 8 from the tip of the piston 4, so that the workability is good even when working in a narrow volume area. Moreover, since the protective disc for protecting the boot 8 is used to hold down the one end 8c, the stability of the assembled state can be ensured.

It is preferable that the protective disk 9 is prevented from rotating between the piston 4 and the piston 4 if necessary. For example, as shown in FIG. 9b, and this projection 9b forms an inner projection 4b in the generatrix direction of the piston 4.
This can be done by sandwiching them in the circumferential direction.

As mentioned above, the disk brake boot protection structure of the present invention can protect the boot well, and the workability of assembling it is greatly improved, and the practical benefits are extremely large. It is.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a disc brake showing an embodiment of the present invention, and FIG. 2 is a view taken in the direction of arrow A in FIG. 1...Rotor, 2...Caliper, 2a, 2b...
...Legs, 2c...Internal protrusion, 3...Cylinder, 4...
...Piston, 4a...Small diameter portion with stepped tip, 4b...
Inner projection, 5... Hydraulic chamber, 6, 7... Friction pad, 8... Boot, 8a... Body, 8bb, 8c
. . . One end, 9 . . . Protective disc, 9 a . . . Cut and raised projection, 9 b .

Claims (1)

[Scope of utility model registration request] In a disc brake in which a dustproof boot is installed across the stepped part of the outer edge of the cylinder of the caliper and the outer periphery of the tip of the piston that is slidably fitted to the cylinder,
a protective disc inserted between the front surface of the piston and the back surface of the friction pad so as to cover the front surface of the piston;
A circumferential projection formed on the stepped portion of the outer edge of the cylinder and forming an overlapping covering portion in the disk axial direction together with the outer circumferential portion of the protective disk, and a boot end portion formed on the outer circumferential portion of the tip of the piston for assembling. A plurality of protrusions are formed on the outer peripheral edge of the protective disk intermittently in the circumferential direction, and the protrusions and the stepped parts of the piston connect the end of the boot to the piston when the boot is assembled to the piston. A disk brake boot protection structure characterized by having two parts sandwiched in the axial direction.