JPH0611369Y2 - Disk brake guide pin structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Use) The present invention relates to a pin structure of a disk brake, and more specifically, is slidably supported in a bag-shaped tubular portion of a caliper. Regarding the structure of the pin.

(Prior Art) In this type of disc brake, when inserting a guide pin, one end of which is fixed to the mounting, into the bottomed tubular portion of the caliper, the boot is attached to the open end of the tubular portion. This is generally done after fitting, so that it is necessary to bleed the air inside the tubular portion in order to facilitate the insertion of the guide pin. Further, when a pair of friction pads arranged in the caliper hold the disk rotor from both sides to stop its rotation, the friction of the pair of friction pads increases the volume of the space at the bottom of the cylindrical portion and the pressure in the space decreases. Negative pressure is generated. This negative pressure acts to hinder the sliding of the caliper, and in order to prevent this, it fits into the groove formed on the outer periphery of the guide pin, which changes the volume opposite to the space according to the wear of the friction pad. It is necessary to communicate between the inner peripheral portion of the boot and the airtight space formed between the outer peripheral portion of the boot fitted to the opening end of the tubular portion.

Therefore, conventionally, a groove is provided on the outer circumference of the guide pin,
Forming chamfers has been used, an example of which is shown in US Pat. No. 4,040,722.

(Problems to be solved by the invention) However, in the above-mentioned conventional guide pin, since the bearing surface portion and the sliding surface portion do not have the same diameter, it is necessary to form a groove in the sliding surface portion after forming each of them. However, there is a problem that the number of processing steps increases and the processing cost increases.

Then, this invention makes it a technical subject to reduce a processing cost by forming a groove | channel at the same time as forming a seat surface part and a sliding surface part.

[Constitution of device]

(Means for Solving the Problem) In the guide pin structure of the disc brake, the grooved means for solving the above-mentioned technical problem is that the seat surface portion and the sliding surface portion of the guide pin have the same diameter. The guide pin is formed by extrusion molding, and at the same time, at least one groove that extends in the axial direction and is shallower than the annular groove is formed on the outer circumferences of the seat surface portion and the sliding surface portion.

(Operation) According to this, the groove can be formed in the sliding surface portion at the same time without increasing the number of processing steps when the guide pin is formed, so that the processing cost can be reduced.

(Embodiment) An embodiment of a disk brake having a guide pin structure according to the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 1 is a disc rotor 1 and 2 which rotate integrally with a wheel, and mounting is fixed to a non-rotating portion (not shown) such as a knuckle of the vehicle inside the vehicle of the disc rotor 1. The mounting 2 supports a friction pad 3 on the vehicle inner side of the disc rotor 1 slidably in the axial direction of the disc rotor 1. A mounting part 7 is a mounting part having a cylinder part 5 for containing a piston (not shown) for pressing the friction pad 3 against the disc 1 and a rear part 6 for pressing the friction pad 4 located outside the vehicle of the disc rotor 1 against the disc rotor 1. 2 includes a tubular portion 8 having a bottomed guide hole 8a located inside the vehicle and a tubular portion 9 having a penetrating guide hole (not shown). The cylindrical portions 8 and 9 are slidably fitted on the sliding surface portion 10b of the guide pin 10 fixed to the mounting 2, so that the carrier 7 is attached to the mounting 2 in the axial direction of the disc rotor 1. Slidably supported on. On the vehicle outer side of the tubular portion 8 of the caliper 7, an inner peripheral end portion 11a is formed on an annular groove 10a formed on the outer periphery of the guide pin 10, and an outer peripheral end portion 11b is formed on an open end portion of the tubular portion 8. Boots 11 that are liquid-tightly fitted in the annular grooves are provided, and an elastic bush (not shown) is fitted to the inner peripheral surface of the guide hole of the tubular portion 9. The thin portion of the bush that extends inside the vehicle surrounds the sliding surface of the guide pin and is protected from the intrusion of water, foreign matter, and the like from pebbles that are wheeled up by the wheels.

As shown in FIGS. 1 to 3, the guide pin 10 has a screw portion 10c formed at one end thereof to be screwed into the mounting portion 2 and is pressed against the mounting portion 2 adjacent to the screw portion 10c. A seat surface portion 10d is formed. The seat surface portion 10d has the same diameter as the sliding surface portion 10b, the guide pin 10 is formed by extrusion, and then the annular groove 1 is formed.
0a is formed by cutting. Further, in this embodiment, the guide pin 10 has a groove 10e that extends in the axial direction and is shallower than the annular groove on the outer periphery of the seat surface portion 10d and the sliding surface portion 10b.
It is formed at the same time when molding.

In the present embodiment having the above-mentioned configuration, when the pressure liquid from the master cylinder (not shown) is supplied to the cylinder portion, the piston (not shown) presses the friction pad 3 against the disk rotor 1 and the reaction force thereof causes the caliper 7 to move. It is guided by the guide pin 10 and slides toward the inside of the vehicle, and presses the friction pad 4 against the disc rotor 1 via the rear portion 6 to exert a braking action.

Therefore, in this embodiment, the guide pin 10 is formed by extrusion with the seat surface portion 10d and the sliding surface portion 10b having the same diameter, and at the same time, the seat surface portion 10 is formed.
A groove 10e that extends in the axial direction and is shallower than the annular groove 10a is formed on the outer periphery of each of the d and the sliding surface portion 10b. Therefore, when the outer periphery end 11b of the boot 11 is fitted into the opening end of the tubular portion 8 when the caliper 7 is assembled,
When the guide pin 10 is inserted into the guide hole 8a, even if the inner peripheral end portion 11a of the boot 11 is on the sliding surface portion 10b, the air in the air chamber 12 at the bottom portion of the guide hole 8a is outward through the groove 10e. It can be easily assembled. Also, when the friction pads 3 and 4 rub, or when the caliper 7 moves to the inside of the vehicle when the disc brake is operated,
Since the air chamber 12 and the sealed chamber 13 that is formed between the inner and outer peripheral end portions 11a and 11b of the boot 11 and changes the volume opposite to the air chamber 12 are communicated with each other through the groove 10e, the caliper 7 is smooth. Then slide on the guide pin 10. Further, in the present embodiment, the groove 10e can be formed in the sliding surface portion 10b at the same time without increasing the number of processing steps when forming the guide pin 10, so that the processing cost can be reduced and the bottom surface portion 10d can be formed. After the disc brake is assembled, it is possible to visually confirm whether or not the position of the groove 10e is in a portion which is not subjected to the brake torque and the vibration load in the vertical and longitudinal directions of the vehicle after the assembling of the disc brake.

Although one groove 10e is provided in the sliding surface portion 10b and the seat surface portion 10d in the above-described embodiment, a plurality of grooves may be provided.

[Effect of device]

As described above, according to the present invention, it is possible to simultaneously form a groove on the sliding surface portion of the guide pin without increasing the number of processing steps when molding the guide pin, so that the processing cost can be reduced.

[Brief description of drawings]

FIG. 1 is a plan view of a disc brake using an embodiment of a guide pin structure according to the present invention, FIG. 2 is a view showing a guide pin according to the present invention, and FIG. 3 is A-A in FIG.
It is a line sectional view. DESCRIPTION OF SYMBOLS 1 ... Disc rotor, 2 ... Mounting, 3, 4 ... Friction pad, 5 ... Cylinder part, 6 ... Reaction part, 7 ...
Caliper, 8 ... Cylindrical part, 8a ... Guide hole, 10 ... Guide pin, 10a ... Annular groove, 10b ... Sliding surface part, 10c ... Screw part, 10d ... Seating part, 10e ... Groove.

Claims (1)

[Scope of utility model registration request] 1. A mounting member fixed to a non-rotating portion of a vehicle on the inside of the disc rotor that rotates integrally with a wheel, and a vehicle disposed inside the mounting member in parallel with the axis of the disc rotor. A guide pin screwed and fixed to the mounting with a screw portion formed at one end of the guide pin, and a seat surface portion of the guide pin is crimped to the mounting member, and a sliding surface portion of the guide pin is slidably fitted and has a bottom. -Shaped tubular portion, a cylinder portion containing a piston for pressing a friction pad on the vehicle inner side of the disk rotor against the disk rotor, and a reaction portion for pushing a friction pad on the vehicle outer side of the disk rotor against the disk rotor. A caliper and an inner peripheral portion of the guide pin are liquid-tightly fitted in an annular groove formed between the seat surface portion and the sliding surface portion on the outer periphery of the guide pin. In a guide pin structure of a disk brake, the outer peripheral portion of which has a boot that is fluid-tightly fitted to the opening end of the tubular portion, the seat surface portion of the guide pin and the sliding surface portion have the same diameter. At the same time, the guide pin is formed by extrusion molding, and at the same time, at least one groove that extends in the axial direction and is shallower than the annular groove is formed on the outer circumferences of the seat surface portion and the sliding surface portion. Brake guide pin structure.