JPH0244619Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a hydraulic master cylinder for hydraulically operating the brakes and clutches of a vehicle.

[Conventional technology]

In some conventional motorcycles, hydraulic master cylinders are provided in the brake paths of the front and rear wheels, and each brake is actuated by hydraulic pressure.

Among these, the rear brake device disclosed in Japanese Utility Model Publication No. 58-23750 describes a technique for operating a brake switch and lighting a brake lamp by the braking action of the brake pedal.

In this brake system, a push rod is pivotally attached to the rear end of the brake pedal via a rod end, and the upper end of the push rod is opposed to the lower end of a piston in a vertical master cylinder fixed to the vehicle body frame. A brake switch main body is fitted and fixed into a hole formed in the push rod substantially parallel to the push rod, and a movable contact protruding downward from the main body is arranged opposite to a plate provided on the push rod or the brake pedal, and when the brake pedal is depressed. As a result, the plate or the rear part of the brake pedal, which rotates upward, pushes the movable contact on the switch body, turning on the brake lamp.

[Problem that the invention attempts to solve]

Therefore, in the above-mentioned brake switch, the brake switch is operated with a pedal stroke that is unrelated to the increase in hydraulic pressure in the master cylinder, which is the point at which the brake is activated. As a result, the operating point of the brake switch changed, and accurate switch operation could not be achieved in accordance with the generated pressure.

SUMMARY OF THE INVENTION An object of the present invention is to provide a hydraulic master cylinder that solves the above problems by operating a switch by moving a piston of the master cylinder that generates hydraulic pressure.

[Means for solving problems]

In order to achieve the above object, the present invention has the rear part of a piston movably inserted into the cylinder of a master cylinder facing the opening of the cylinder, and the piston is moved by pushing a push rod facing the rear part of the piston. In a hydraulic master cylinder for a vehicle that generates pressure fluid in a hydraulic pressure chamber defined between the tip and the bottom of the cylinder, a contact holding member having a through hole for inserting the rear part of the piston into the opening of the cylinder is fixed. A movable contact in the switch circuit is disposed on the outer periphery of the rear end of the piston, and a fixed contact that contacts the movable contact is provided on the inner periphery of the through hole of the contact holding member.

[Effect]

With the above configuration, when the piston moves toward the bottom of the cylinder and generates pressure fluid, both contacts come into contact and the switch circuit is activated.

〔Example〕

Hereinafter, the present invention will be used for the rear brake of a motorcycle. An embodiment applied to a vertical hydraulic master cylinder will be described based on FIG. 1.

The hydraulic master cylinder 1 is composed of a vertical cylinder body 3 having a cylinder 2 opened at the bottom, and a reservoir 4 connected to the upper side of the body 3. The chamber communicates with a leaf port 5 and a support port 6.

A large diameter hole 7 that opens at the lower end of the cylinder body 3 is continuously provided in the lower part of the cylinder 2, and a piston 10 having a primary cup 8 and a secondary cup 9 encircled therein can be moved in a fluid-tight manner. The rear portion 10a thereof is arranged to protrude into the large diameter hole 7.

The piston 10 is made of an insulating material such as synthetic resin, and when the piston 10 is inserted, a hydraulic chamber 11 is defined between the primary cup 8 and the upper wall of the cylinder 2. A return spring 12 contracted therein is biased to a non-operating position where it comes into contact with a stopper plate 14 hooked to a circlip 13 fitted in the large diameter hole 7.

A movable contact 15 is provided on the outer periphery of the end of the rear portion 10a of the piston 10, and an upper end 16a of a push rod 16, which moves up and down when the brake pedal is operated, is opposed to a spherical recess 10b formed in the end surface.

In the large diameter hole 7 of the cylinder body 3, a plate-shaped contact holding member 18 is located at a higher position than the movable contact 15 and is prevented from coming out and whose position is regulated by a nut 17.
A dust boot 19 is attached between the lower end of the cylinder body 3 and the push rod 16.

The contact holding member 18 is made of synthetic resin like the piston 10 described above, and a circular hole 18 having the same shape as the rear part 10a of the piston 10 is provided in the center of the holding member 18.
a is provided, and by attaching the contact holding member 18, the rear portion 10a of the piston 10 is slidably inserted into the circular hole 18a.

Further, the contact holding member 18 is provided with ring-shaped fixed contacts 21a and 21b spaced apart from each other so as to face the circular hole 18a. It is connected to the.

This embodiment is constructed as described above, and when the brake pedal is depressed, the push rod 1
6 moves upward, the upper end 16a of the rod 16 comes into contact with the recess 10b of the piston 10, and the piston 1
0 upward to generate pressure fluid in the upper hydraulic pressure chamber 11. This pressure fluid is supplied to the rear brake from the discharge hole 11a of the hydraulic pressure chamber 11 via the brake hose, and brakes the rear wheels.

Also, due to the movement of this piston 10, the rear part 1
The movable contact 15 provided at 0a is connected to the contact holding member 18
The switch contacts both fixed contacts 21a and 21b, turning on the switch circuit and lighting the brake lamp.

FIG. 2 shows another embodiment, in which the piston 2
2 is made of a conventionally commonly used conductive metal material such as iron or aluminum alloy, and the contact holding member 18, the fixed contact 21a,
Each component such as 21b is constructed in the same manner as in the previous embodiment.

The shaft diameter of the rear part 22a of the piston 22 is formed to be slightly smaller than the circular hole 18a of the contact holding member 18, and a movable contact is provided on the outer periphery of the end thereof, and is insulated from the piston 22 by interposing a synthetic resin plate 2. 24 is inserted in the ring.

This movable contact 24 is formed to have the same shape as the circular hole 18a, and when the piston 22 moves upward to perform hydraulic pressure operation, it comes into contact with both fixed contacts 21a and 21b to energize the switch circuit.

As shown in the above embodiments, the present invention operates the switch by the movement of the piston generated in the hydraulic pressure chamber of the master cylinder, so that the switch is always linked to the braking activation point. The brake lamp can be turned on, and by screwing the contact holding member and moving it up and down, the operating timing of the switch can be easily changed regardless of the piston or push rod.

Furthermore, both the movable and fixed contacts are housed inside the dust boot of the hydraulic master cylinder, preventing rainwater and mud from entering from the outside, ensuring reliable operation, and preventing the secondary cup from being damaged. Even in the event of a fluid leak, the conductive hydraulic fluid acts as a contact and lights up the brake light continuously.
Abnormal conditions can be detected early.

In both of the above embodiments, the contact holding member is fixed in the cylinder by screws, but it may be attached by press fitting or other means.

In addition, the hydraulic master cylinder of the present invention can be used not only for rear brakes, but also for front brakes and tandem specifications of motorcycles, and brakes for four-wheeled vehicles, and can also be used as a safety switch for hydraulic clutches. Can be done.

[Effect of idea]

As explained above, in the hydraulic master cylinder of the present invention, the rear part of the piston movably inserted into the cylinder of the master cylinder faces the opening of the cylinder, and the rear part of the piston is inserted into the opening of the cylinder. Fix the contact holding member with the through hole,
The movable contact in the switch circuit is placed on the outer periphery of the rear end of the piston, and the fixed contact that contacts this movable contact is provided on the inner periphery of the contact holding member, so the structure is simpler and cheaper than conventional products. Furthermore, by adjusting the operating members such as the brake pedal and the clutch lever, there is no deviation in the operating timing of the switch, and the switch can always be operated in accordance with the point at which pressure fluid is generated.

[Brief explanation of the drawing]

FIG. 1 is a partially cross-sectional front view of a vertical hydraulic master cylinder, and FIG. 2 is a cross-sectional front view of main parts showing another embodiment. 1...Hydraulic pressure master cylinder, 2...Cylinder,
3... Cylinder body, 7... Large diameter hole, 10...
Piston, 10a... Rear part of piston 10, 11
... Hydraulic pressure chamber, 15 ... Movable contact, 16 ... Push rod, 17 ... Nut, 18 ... Contact holding member, 19 ... Dust boot, 20 ... Lead wire,
21a, 21b...Fixed contacts.

Claims (1)

[Scope of utility model registration request] A hydraulic chamber is defined between the tip of the piston and the bottom of the cylinder by forcing the rear part of a piston movably inserted into the cylinder of the master cylinder to face the opening of the cylinder, and by pushing a push rod facing the rear part of the piston. In a vehicle hydraulic master cylinder that generates pressure fluid, a contact holding member having a through hole through which the rear part of the piston is inserted is fixed in the opening of the cylinder, and a contact holding member in a switch circuit is attached to the outer periphery of the rear end of the piston. A hydraulic master cylinder for a vehicle, characterized in that a movable contact is arranged and a fixed contact that contacts the movable contact is provided on the inner periphery of a through hole of a contact holding member.