JP2001263394A - Caliper body of disk brake for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To miniaturize a caliper body, and to reduce the weight thereof by shortening the length of the caliper body in the axial direction of a disk. SOLUTION: One working part 3a is provided with a working hole 12 formed with a large diameter at a disk rotor side thereof. A large diameter part 12b of the working hole 12 is sealed by a cylindrical sealing member 13 having a bottom, and a cylinder hole 5 is formed of a cylindrical part 13a and a small diameter part 12a of the working hole 12. A rear side of a piston 7 is housed in the cylindrical part 13a. A clearance B is formed between the cylindrical part 13a of the sealing member 13 and the piston 7 housed in the cylindrical part 13a. A communication groove 17 to be communicated with the clearance B is formed in the small diameter part 12a of the working hole 12. A liquid passing hole 20 is communicated with the communication groove 17.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a caliper body of a disc brake for a hydraulic vehicle used for a running vehicle such as an automobile or a motorcycle, and more particularly, to a caliper body having a pair of working portions disposed with a disc rotor interposed therebetween. The present invention relates to a monocoque-type piston-facing caliper body integrally formed integrally with a bridge portion connecting these members across the outer periphery of a disk rotor.

[0002]

2. Description of the Related Art In a monocoque type caliper body having a piston opposed to a pair of working parts, a cutting tool for machining a cylinder hole for mounting a piston is inserted between both working parts. Since there is no dimensional margin, a working hole is formed in one working portion of the caliper body in the axial direction of the disc, and a cylinder hole is cut through the other working portion through the working hole.

[0003] One of the working holes has a large-diameter portion on the side opposite to the disk rotor and a stepped hole on the small-diameter portion on the disk rotor side, and a cylinder hole is cut into the other working portion through the processing hole of one working portion. After that, the cylinder hole is formed in one of the action portions by closing the large diameter portion with the closing member.

In such a caliper body, the bottom of the cylinder hole of one of the working portions is closed by a separate closing member, so that the wall surface of the caliper body itself is compared with the other working portion using the bottom wall of the cylinder hole. It is necessary to set the thickness of the closing member to be large or to secure a sufficient fitting length between the closing member and the large-diameter portion of the processing hole. However, the size of the caliper body has been increased and the weight has also been increased, leading to an increase in unsprung load.

[0005] For this reason, for example, Japanese Unexamined Patent Publication No.
In the prior art shown in the publication, a closing member for closing a large-diameter portion of a processing hole of one working portion is formed in a bottomed cylindrical shape, and the cylindrical portion of the closing member and the small-diameter portion of the processing hole form one of the two. By forming the cylinder hole of the action part and accommodating the bottom side of the piston in the cylindrical part of the closing member, the caliper body is prevented from increasing in length in the disk axial direction and weight.

[0006]

In such a caliper body of the piston opposed type, all hydraulic pressures are supplied to supply the hydraulic fluid pressurized by a separate hydraulic master cylinder to the respective hydraulic chambers. In the above-mentioned prior art, a union hole for introducing hydraulic fluid is formed in a closing member serving as a bottom wall of the hydraulic chamber of one of the working portions, and the union screwed into the union hole is required. Connect the banjo at the end of the brake hose connected to the hydraulic master cylinder with bolts,
Further, the banjo and the other hydraulic chamber are connected by a hydraulic pipe, and the hydraulic chambers of both working parts are communicated.

For this reason, the boss portion for mounting the union bolt projects from the outer surface of the closing member, and the head of the union bolt and the banjo project from the outer surface of the boss portion. It was difficult to shorten it. In addition, since a metal liquid pipe connecting the hydraulic chambers to the caliper body is added, the assembly process and the weight increase are disadvantageous. In particular, when the number of pistons is as large as 4 pots or 6 pots, it is more disadvantageous. In consideration of an unexpected external force such as a stepping stone, it is desirable to avoid as much as possible to bypass the liquid passage pipe outside the caliper body. It is.

As a countermeasure, there is a means of eliminating the external liquid pipe by circulating a liquid hole inside the caliper body and connecting the hydraulic chambers with the liquid hole. The hydraulic chamber of one of the working parts is located at the bottom of the closed cylindrical member with a bottom, and the square seal is located at the middle part of the cylinder hole. It is extremely difficult to communicate the liquid passage with the hydraulic chamber while avoiding the obstruction and the closing member.

Accordingly, the present invention provides a caliper body of a disc brake for a vehicle which can reduce the length of the caliper body in the disc axial direction as much as possible while minimizing the size and weight while solving the above-mentioned problems. It is an object.

[0010]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention comprises a pair of working portions arranged with a disk rotor interposed therebetween, and a bridge portion connecting the two working portions across the outer periphery of the disk rotor. A bottomed cylinder that is formed integrally with one working part and has a small-diameter part on the disk rotor side and a large-diameter part on the opposite disk rotor side penetrating in the disk axial direction, and an opening on the other working part toward the disk rotor side. A hole is formed coaxially with the processing hole, and a large-diameter portion of the processing hole is liquid-tightly closed by a closed-end cylindrical closing member, and the cylindrical portion of the closing member and the small-diameter portion of the processing hole are closed. In the one acting portion, a bottomed cylinder hole is provided to be open to the disk rotor side, a piston is movably inserted into each cylinder hole, and a hydraulic chamber is defined at the bottom side of each cylinder hole. The hydraulic pressure chamber is connected with a hydraulic fluid passage. In the caliper body of the vehicle disc brake provided as described above, a gap is formed between the closing member and a rear outer peripheral surface of a piston housed inside the closing member, and the gap is formed in a small diameter portion of the machining hole. And a communication groove communicating with the liquid communication hole is formed in the communication groove.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

A hydraulic disc brake 1 includes a disc rotor 2 that rotates integrally with a wheel (not shown) in the direction of arrow A.
And a caliper body 3 attached to the vehicle body at one side of the disc rotor 2, and a pair of friction pads 4, 4 arranged inside the caliper body 3 with the disc rotor 2 interposed therebetween. .

The caliper body 3 has a pair of working portions 3a and 3b disposed with the disk rotor 2 interposed therebetween, and a bridge portion 3c which straddles the outer periphery of the disk rotor 2 and connects them.
Are integrally formed, and one of the action portions 3a and the other
b, four cylinder holes 5, 5, 6, 6 are provided facing each other,
Each of the cylinder holes 5, 5, 6, 6 has a cup-shaped piston 7,
With a monocoque four-pot opposed caliper with 8 interpolated,
A boss 3d for mounting the vehicle body integrally formed on the other working portion 3b is fixedly mounted on a vehicle body (not shown) with a mounting bolt.

The cup-shaped pistons 7, 7, 8, 8 are inserted in cylinder holes 5, 6 in a liquid-tight and movably manner using square seals 9, respectively. Between the bottom walls of the cylinder holes 5, 5, 6, and 6, the hydraulic pressure chamber 1
0, 10, 11 and 11 are defined, and friction pads 4 and 4 are arranged on the front surfaces of the pistons 7 and 8 to face each other with the disk rotor 2 interposed therebetween. The friction pads 4, 4 are formed by fixing a lining 4 a slidably in contact with the side surface of the disk rotor 2 to a metal back plate 4 b.
a and 3b so as to be movable in the disk axis direction.

Although the cylinder holes 5 and 6 are formed by cutting after casting, there is room for inserting a cutting tool between the working portions 3a and 3b where the outer peripheral portion of the disk rotor 2 is disposed. First, one of the action parts 3a
Two stepped processing holes 12, 12 are formed to penetrate in the disk axial direction. The machining hole 12 has a small-diameter portion 12a on the disk rotor side and a large-diameter portion 12b on the opposite side to the disk rotor. A circumferential step is formed between the small-diameter portion 12a and the large-diameter portion 12b. A female screw 12c for attaching a closing member is engraved on the large diameter portion 12b.

The machining of the cylinder hole 6 on the side of the working portion 3b is performed through the above-described working hole 12, and is formed in the other working portion 3b by the cutting of a cutting tool projecting from the working hole 12 to the other working portion 3b. Cylinder holes 6 and 6 having a bottom cylindrical shape are provided so as to open to the disc row side. Next, a closing member 13 is screwed into the large-diameter portion 12b of the processing hole 12, and the non-disk rotor side of the processing hole 12 is closed with the closing member 13.
By sealing the space between the cylindrical portion 13a and the large-diameter portion 12b in a liquid-tight manner with a sealing material 14 such as an O-ring, cylinder holes 5 and 5 that open to the disc row side are provided in one of the action portions 3a.

The closing member 13 is formed in a bottomed cylindrical shape comprising the above-mentioned cylindrical portion 13a and a bottom wall 13b for closing one end of the cylindrical portion 13a.
b on the outer peripheral surface over the edge of the female screw 12c of the large diameter portion 12b
The external thread 13c which is screwed is formed. Cylindrical part 13
a has an inner diameter slightly larger than the small diameter portion 12 a of the processing hole 12, and the cylindrical portion 13 a and the small diameter portion 12 a
a constitutes the cylinder hole 5 of the one action portion 3a.

The piston 7 inserted into the cylinder hole 5
The rear portion on the bottom wall side is housed in the cylindrical portion 13a of the closing member 13, which helps to reduce the length of the caliper body 3 in the cylinder axial direction. The above-mentioned hydraulic chamber 10 is defined in the cylindrical portion 13a of the closing member 13, and the outer peripheral surface of the piston 7 and the cylindrical portion 1 of the closing member 13 having a larger diameter than this.
A gap B is formed between the hydraulic chamber 10 and the processing hole
The second small diameter portion 12a is defined.

The two hydraulic chambers 10, 10 adjacent to one of the action portions 3a communicate with communication grooves 15, 16, which will be described later.
In addition, two hydraulic chambers 11, 1 adjacent to each other in the other working portion 3b
1 communicates with each other through a communication hole 18.

A communication groove 15 is formed in the cylinder hole 5 of the working portion 3a on the disk entry side, and a communication groove 15 is formed in the large-diameter hole end of the small-diameter portion 12a on the disk entry side. In the small-diameter portion 12a, communication grooves 16 and 17 are respectively formed on both sides of the large-diameter hole side end disk of the small-diameter portion 12a. Communication groove 15
To 17 are formed in a crescent shape extending radially outward from the small-diameter portion 12a, and further open to the small-diameter portion 12a and the large-diameter portion 12b. Is in communication with The communication grooves 15, 16 recessed in the partition wall between the cylinder holes 5, 5 are cut to each other to a little more than half the length of the partition wall, and their ends are connected to each other. The communication groove 17 located on the disk outlet side is formed in a wedge shape whose cross-sectional planar shape expands toward the small-diameter portion 12a.

On the disc outlet side of the caliper body 3,
A liquid passage hole 19 is drilled from one operating portion 3a to the hydraulic chamber 11 on the disk outlet side of the other operating portion 3b, and the other operating portion 3b is provided on the disk outlet side of one operating portion 3a. A liquid passage hole 20 is formed toward the communication groove 17 formed in the processing hole 12, and the liquid passage holes 19 and 20 intersect at an intermediate portion. A union hole 21 is formed in an outer surface opening of one of the liquid holes 19, and a bleeder hole 22 is formed in an outer surface of the other liquid hole 20. A brake hose is formed in the union hole 21. And a bleeder screw 23 is screwed into the bleeder hole 22, respectively.

One of the liquid holes 19 communicates with the hydraulic chamber 11 on the disk inlet side through the hydraulic chamber 11 on the disk outlet side and the communication hole 18, and the other liquid hole 20 communicates with the communication groove 17 on the disk inlet side. And the gap B to the hydraulic chamber 10 on the disc outlet side,
Further, it communicates with the hydraulic chamber 10 on the disk reciprocating side through the gap B and the communication grooves 16 and 15.

In this embodiment constructed as described above, the hydraulic fluid pressurized by a hydraulic master cylinder (not shown) by the driver's brake operation is introduced into the union hole 21 of the caliper body 3 through the brake hose. Further, the fluid communication holes 19, 20 are branched to form four hydraulic chambers 10, 10,.
11 and 11 are supplied. Hydraulic chambers 10, 10, 11, 1
The hydraulic fluid supplied to 1 is supplied to each piston 7, 7,
8, 8 are pushed in the direction of the opening of the cylinder hole, and the pistons 7, 7, 8, 8 push the friction pads 4, 4 in the direction of the disk rotor, whereby a braking action is performed.

As described above, in the present embodiment, the closing member 13 for closing the machining hole 12 with the one working portion 3a of the caliper body 3 is formed in a cylindrical shape with a bottom, and the cylindrical portion 13a of the closing member 13 is formed.
And the small-diameter portion 12a of the processing hole 12 constitute the cylinder hole 5, and the rear side of the piston inserted into the cylinder hole 5 is accommodated in the cylindrical portion 13a of the closing member 13 and located at the bottom of the closing member 13. Since the fluid pressure chamber 10 and the fluid communication hole 20 communicate with each other through the communication groove 17 and the gap B, the length of the caliper body 3 in the disk axis direction can be reduced. Further, since the four hydraulic chambers 10, 10, 11, and 11 are communicated within the caliper body 3, a metal liquid pipe conventionally attached to the caliper body 3 is unnecessary, and the caliper body 3 is compact and compact. Weight reduction and reduction of unsprung load can be achieved. Moreover, since the boss, the head of the union bolt, the banjo, and the like do not protrude from the outer surface of the closing member 13, the size and weight can be further reduced, and the unsprung load can be reduced.

Further, since the communication groove 17 of the cylinder hole 5 with which the liquid through hole 20 communicates has a shape that extends radially outward from the small diameter portion 12a of the processing hole 12, the capacity in the direction of drilling the liquid through hole 20 is reduced. Because of the expansion, even if the square seal 9 is located in the middle of the cylinder hole 5, the caliper body 3 can be easily avoided without increasing the length of the caliper body 3 in the disk axis direction, and simple hole processing can be performed. become. Therefore, it can be said that as the communication groove 17 expands outward in the radial direction, the hole processing of the liquid through hole 20 can be more easily performed.

The caliper body of the present invention can be applied not only to the four-pot facing type of the embodiment, but also to a two-pot or six-pot or more facing type. Further, the communication groove communicating with the liquid through hole may have a shape other than that of the embodiment, or may be formed on the entire periphery of the processing hole and the small diameter portion.

[0027]

As described above, according to the present invention,
The length of the caliper body in the axial direction of the disc is kept short, and the metal fluid pipes that have been externally attached to the caliper body are no longer required, making it possible to reduce the size and weight of the caliper body and reduce the unsprung load. . Further, since the boss, the head of the union bolt, the banjo, and the like do not protrude from the outer surface of the closing member, it is possible to further reduce the size and weight and reduce the unsprung load.

Further, the communication groove connected to the liquid hole has a shape extending radially outward from the small diameter portion of the processing hole.
Since the capacity in the direction of drilling the liquid through hole is expanded, it is possible to easily avoid square seals and the like and easily perform hole processing without increasing the length of the caliper body in the disk axial direction.

[Brief description of the drawings]

FIG. 1 is a sectional view taken along a line II in FIG. 3;

FIG. 2 is a partial cross-sectional rear view of a caliper body showing one embodiment of the present invention.

FIG. 3 is a front view of a caliper body showing one embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Disc brake, 2 ... Disc rotor, 3 ... Caliper body, 3a ... One working part, 3b ... The other working part, 3c ... Bridge part, 4 ... Friction pad, 4a ... Lining, 4b ... Back plate, 5, 6 ... Cylinder hole, 7,8 ... Piston, 10, 11 ... Hydraulic chamber, 12 ... Working hole, 12a ...
Small diameter portion, 12b Large diameter portion, 13 Closing member, 13a Cylindrical portion, 13b Bottom wall, 14 Sealing material, 15, 16, 1
7: communication groove, 18: communication hole, 19, 20: liquid hole, B:
Air gap between cylindrical portion 13a and piston 7

Claims (1)

[Claims] 1. A pair of working parts disposed so as to sandwich a disk rotor and a bridge part connecting both working parts across the outer periphery of the disk rotor, and one of the working parts is a small diameter part on the disk rotor side. On the other side, a machining hole of a large diameter portion is formed through the machining axis of the disc in the axial direction, and a cylinder with a bottom opening to the disc rotor side is formed coaxially with the machining hole on the other working portion. The large-diameter portion of the hole is closed in a liquid-tight manner with a closed-end cylindrical closing member, and the cylindrical portion of the closing member and the small-diameter portion of the processing hole have a bottomed cylinder hole in the one working portion and a disk rotor. Opened to the side and provided
A piston is movably inserted into each cylinder hole,
In a caliper body of a disc brake for a vehicle in which a hydraulic pressure chamber is defined on the bottom side of each cylinder hole and a hydraulic fluid communication hole is provided in communication with the hydraulic pressure chamber, the closing member and the closing member A gap is formed between the piston and the outer peripheral surface on the rear side of the piston housed therein, a communication groove communicating with the gap is formed in the small diameter portion of the machining hole, and the liquid communication hole communicates with the communication groove. A caliper body for a disc brake for a vehicle.