JP2005289180A - Hydraulic master cylinder for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To excellently secure the flowability of a working fluid between a reservoir and a cylinder bore with a simple structure, and further to reduce the size and weight of a hydraulic master cylinder, and to improve the mountability to a car body, by forming a communicating passage forming portion to be small. <P>SOLUTION: The reservoir 3 having an oil storage chamber 3a is integrally formed on the upper portion on the side portion of a cylinder body 2 having a long cylinder bore 2a. The communicating passage forming portion 4 is provided between the bottom portion of the oil storage chamber 3a and the side portion of the cylinder body 2. A relief port 5 and a supply port 6, which serve as an oil passage hole communicating with the cylinder bore 2a, and an oil passage 7, which communicates with the oil storage chamber 3a and crosses the relief port 5 and the supply port 6, are formed in the communicating passage forming portion 4. The oil passage 7 is so formed as to tilt its side opposite to the reservoir toward the cylinder bore 2a with respect to the axis L2 of the oil storage chamber 3a. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a hydraulic master cylinder for a brake mounted on a motorcycle, and more specifically, to a hydraulic pressure for a vehicle integrally provided with a reservoir above a side of a cylinder body having a vertically long cylinder hole in the vertical direction. Regarding the master cylinder.

  Conventionally, in a vehicular hydraulic master cylinder in which a reservoir having a liquid storage chamber is integrally formed above a side portion of a cylinder body having a vertically long cylinder hole, a bottom portion of the liquid storage chamber and a side portion of the cylinder body are provided. A communication passage forming portion is provided between the two liquid passage holes communicating with the cylinder hole, the liquid passage communicating with the liquid storage chamber, and intersecting the two liquid passage holes. And are formed.

The fluid passage hole supplies hydraulic fluid to a fluid pressure chamber and a replenishment fluid chamber defined in the cylinder hole, and a through hole perpendicular to the cylinder axis is formed in the communication path forming portion toward the cylinder hole. It is formed by press-fitting a steel ball into the opening on the side opposite to the cylinder hole of the through hole. The liquid passage extends from the bottom of the liquid storage chamber in the axial direction of the liquid storage chamber, and is formed so as to intersect the two liquid passage holes (for example, Patent Document 1).
JP 2001-140801 A

  However, in the above, the liquid passage formed in the communication passage forming portion extends in the axial direction of the liquid storage chamber, so that the steel ball provided in the liquid passage hole and the liquid passage do not cross each other. Each liquid passage hole had to be formed long. For this reason, there is a problem that the communication path forming portion must be formed large in the direction orthogonal to the cylinder axis, and the hydraulic master cylinder is heavy.

  Therefore, the present invention has a simple structure, ensures good fluid flowability between the reservoir and the cylinder hole, and reduces the size and weight of the hydraulic master cylinder by forming the communication passage forming portion small. It is aimed.

  To achieve the above object, according to the present invention, a reservoir having a liquid storage chamber is integrally formed above a side portion of a cylinder body having a vertically long cylinder hole, and a bottom portion of the liquid storage chamber and a side portion of the cylinder body are formed. The communication passage forming portion is provided with a liquid passage hole communicating with the cylinder hole and a liquid passage communicating with the liquid storage chamber and intersecting with the liquid passage hole. In the vehicular hydraulic master cylinder, the fluid passage is formed by inclining the opposite reservoir side of the fluid passage toward the cylinder hole side with respect to the axis of the liquid storage chamber, and the cylinder body and the reservoir May be formed such that the axis of the cylinder hole and the axis of the liquid storage chamber are non-parallel.

  According to the above-described invention, since the length of the fluid passage hole communicating with the cylinder bore can be shortened, the communication passage forming portion can be formed small, and the hydraulic master cylinder can be reduced in size and weight.

  Hereinafter, an embodiment in which the present invention is applied to a hydraulic master cylinder for a rear wheel brake of a motorcycle will be described in detail with reference to the drawings. The hydraulic master cylinder 1 of the present embodiment is an example in which a vertically long cylindrical reservoir 3 is integrally formed on the upper side of a vertically long substantially cylindrical cylinder body 2, and the cylinder body 2 and the reservoir 3 are: The axis L1 of the cylinder hole 2a formed in the cylinder body 2 and the axis L2 of the liquid storage chamber 3a formed in the reservoir 3 are set to be non-parallel, and the bottom side of the liquid storage chamber 3a is It is formed to be inclined toward the cylinder hole 2a. A communication passage forming portion 4 is formed between the bottom of the liquid storage chamber 3a and the side portion of the cylinder body 2, and the relief passage 5 and the supply port serving as the liquid passage holes of the present invention are formed in the communication passage forming portion 4. 6 and a liquid passage 7 are formed.

  The cylinder body 2 is formed with a vertically long bottomed cylinder hole 2a with its lower end opened, and a piston 8 is inserted into the cylinder hole 2a using a primary cup 9 and a secondary cup 10 so as to be liquid-tight and movable. In addition, a hydraulic chamber 11 is defined between the piston 8 and the upper wall of the cylinder hole 2a, and a replenishing fluid chamber 12 is defined between the intermediate portion of the piston 8 and the peripheral wall of the cylinder hole 2a. A return spring 13 is contracted between the piston 8 and the upper wall of the cylinder hole 2a, and the piston 8 is urged downward by the elastic force of the return spring 13 to move backward. The limit is regulated by contact with the head 15a of the push rod 15 that is locked to the circlip 14 that is engaged with the opening of the cylinder hole 2a. A union hole 16 is provided in the hydraulic chamber 11 so as to communicate therewith.

  The reservoir 3 has a liquid storage tank 3b formed integrally with the cylinder body 2, and a lid member 3c attached to the upper opening of the liquid storage tank 3b, and a diaphragm 17 is sandwiched between them. It is worn. Inside the liquid storage tank 3b, the vertically long liquid storage chamber 3a is provided.

  The communication path forming portion 4 is formed integrally with the reservoir 3 and the cylinder body 2 and protrudes downward from the bottom of the liquid storage tank 3b and protrudes from the side of the cylinder body 2 in a direction perpendicular to the cylinder axis. Two through holes perpendicular to the cylinder axis are formed in the communication path forming portion 4 from the outer surface toward the cylinder hole 2a, and steel balls 18 are press-fitted into the openings on the side opposite to the cylinder hole of the through holes, respectively. A relief port 5 that is closed and communicated with the hydraulic pressure chamber 11 and a supply port 6 that communicates with the replenishing fluid chamber 12 are formed. Further, a liquid passage 7 that intersects with the relief port 5 and the supply port 6 and communicates with the bottom of the liquid storage chamber 3a is formed in the communication passage forming portion 4. The liquid passage 7 is formed such that the axis L3 of the liquid passage 7 is inclined with respect to the cylinder hole 2a by the angle A with respect to the axis L2 of the liquid storage chamber. The liquid storage chamber 3a and the cylinder hole 2a communicate with each other through the relief port 5, the supply port 6 and the liquid passage 7, so that the hydraulic fluid F can flow between the liquid storage chamber 3a and the cylinder hole 2a. Yes.

  The present embodiment is configured as described above, and the hydraulic master cylinder 1 is in the state shown in FIG. 1 when not operating the brake pedal 19. When the brake pedal 19 is depressed, the push rod 15 is moved upward to push the piston 8 upward in the cylinder hole 2a, and the hydraulic fluid F in the hydraulic pressure chamber 11 passes through the relief port 5 and the fluid passage 7. After returning to the liquid storage chamber 3a of the reservoir 3, the primary cup 9 closes the relief port 5, and the flow of the hydraulic fluid F is interrupted, the hydraulic fluid F in the hydraulic chamber 11 is gradually increased in pressure. Further, as the piston 8 is pushed upward, the supply port 6 and the replenishing liquid chamber 12 communicate with each other.

  The hydraulic fluid F boosted in the hydraulic chamber 11 is sent from the upper union hole 16 through the brake hose to the caliper body of the rear wheel brake, and brakes a disc rotor (none of which is shown) that rotates integrally with the rear wheel. To do. When the braking is released, the piston 8 returns to the original position by the elastic force of the return spring 13. At this time, as the primary cup 9 moves away from the relief port 5 and the hydraulic chamber 11 expands, the hydraulic fluid F is introduced into the hydraulic chamber 11 from the storage chamber 3a via the relief port 5 and the fluid passage 7. The

  In the hydraulic master cylinder 1 described above, the liquid passage 7 is formed such that the axis L3 of the liquid passage 7 is inclined with respect to the axis L2 of the liquid storage chamber 3a by an angle A on the side opposite to the reservoir 2a. As a result, the relief port 5 and the supply port 6 can be formed shorter than before, the communication path forming portion 4 can be formed smaller than before, and the hydraulic master cylinder 1 can be reduced in size and weight and mounted on the vehicle body. It is possible to improve the performance.

  In the above-described embodiment, the bottom of the liquid storage chamber is inclined toward the cylinder hole so that the axis of the cylinder hole and the axis of the liquid storage chamber are not parallel to each other. It is not limited to this, and the upper opening side of the liquid storage chamber may be inclined to the cylinder hole side, and the axis of the cylinder hole and the axis of the liquid storage chamber are formed in parallel. But you can.

It is a section front view of a hydraulic master cylinder showing an example of the present invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Hydraulic master cylinder, 2 ... Cylinder body, 2a ... Cylinder hole, 3 ... Reservoir, 3a ... Liquid storage chamber, 3b ... Liquid storage tank, 3c ... Lid member, 4 ... Communication path formation part, 5 ... Relief port, 6 ... Supply port, 7 ... Fluid passage, 8 ... Piston, 9 ... Primary cup, 10 ... Secondary cup, 11 ... Fluid pressure chamber, 12 ... Supply fluid chamber, 13 ... Return spring, 14 ... Circlip, 15 ... Push rod , 16 ... Union hole, 17 ... Diaphragm, 18 ... Steel ball, 19 ... Brake pedal, L1 ... Axis of cylinder hole, L2 ... Axis of liquid storage chamber, L3 ... Axis of liquid passage, F ... Hydraulic fluid

Claims (2)

A reservoir having a liquid storage chamber is integrally formed above the side of the cylinder body having a vertically long cylinder hole, and a communication path forming portion is provided between the bottom of the liquid storage chamber and the side of the cylinder body, In the hydraulic master cylinder for a vehicle, wherein the communication passage forming portion includes a liquid passage hole communicating with the cylinder hole and a liquid passage communicating with the liquid storage chamber and intersecting the liquid passage hole. Is a hydraulic master cylinder for a vehicle, wherein the reservoir side of the fluid passage is inclined toward the cylinder hole with respect to the axis of the fluid storage chamber. 2. The vehicle hydraulic master cylinder according to claim 1, wherein the cylinder body and the reservoir are formed so that an axis of the cylinder hole and an axis of the liquid storage chamber are not parallel to each other. .

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