JPH0244620Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] 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 in response to 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 rise in hydraulic pressure in the master cylinder, which is the point at which the brake is activated. The operating point of the switch changed, and accurate switch operation could not be obtained depending on 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 includes a piston that is movably inserted into the cylinder of a master cylinder, and a push rod that pushes the piston, with its tip facing into the opening of the cylinder. In a hydraulic master cylinder for a vehicle that generates pressure fluid in a hydraulic pressure chamber of a cylinder, a fixed contact of a switch circuit is disposed at the open end of the cylinder, and a fixed contact of a switch circuit is disposed on the push rod so as to move toward the cylinder as the push rod moves forward. hand,
The present invention is characterized in that a movable contact is provided that contacts the fixed contact.

[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〕

An embodiment in which the present invention is applied to a vertical hydraulic master cylinder used in a rear brake of a motorcycle will be described below with reference to the drawings.

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 relief port 5 and a supply 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 end surface 10b, which can be fitted into the cylinder 2 and has a spherical recess 10a, faces the open end of the cylinder 2.

The upper part of the push rod 11, which moves up and down when the brake pedal is operated, is inserted into the large diameter hole 7, and the stepped portion 11c between the head 11a and the shaft 11b.
, there is a stopper 13 for preventing removal and regulating the position, which is hooked on the circlip 12 fitted in the large diameter hole 7.
And a stopper plate 14 is mounted on the ring.

The piston 10 is made of an insulating material such as synthetic resin, and when the piston 10 is inserted, a hydraulic chamber 15 is defined between the primary cup 8 and the upper wall of the cylinder 2. The rear end 10b is brought into contact with the head 11a of the push rod 11 by the biasing force of the return spring 16 contracted therein.

A fixed contact 19 is provided at a stepped portion 17 between the cylinder 2 and the large diameter hole 7 of the cylinder body 3 via an insulating synthetic resin plate 18.

The stopper plate 14 has a stopper 13 on its upper surface, and a plate spring 20 that urges the push rod 11, which is engaged with the stopper 13, upwardly. A movable contact 21 is provided which comes into contact with the fixed contact 19 when the vehicle is moved, and both contacts 19 and 21 are connected to a lead wire 23 of a switch circuit that turns on a brake lamp 22.

The elastic force of the leaf spring 20 is set to be weaker than that of the return spring 16 provided in the hydraulic chamber 15, and in the non-braking position where the piston 10 and push rod 11 are urged downward by the return spring 16. , both contacts 19 and 21 do not contact.

Note that 24 is a dust boot fitted between the large diameter hole 7 of the cylinder body 3 and the push rod 11.

This embodiment is constructed as described above, and when the brake pedal is depressed, the push rod 1
1 moves upward, the upper end 11a of the rod 11 pushes the piston 10 upward, and the upper hydraulic pressure chamber 15
Generates pressure fluid inside. This pressure fluid is transferred to the hydraulic chamber 15
It is supplied to the rear brake from the discharge hole 15a through the brake hose, and brakes the rear wheel.

Further, due to the movement of the piston 10, the stopper 13 is pushed upward by the leaf spring 20 whose elastic force is released, and the movable contact 21 of the stopper 13 is pushed upward.
contacts the fixed contact 19 and the switch circuit turns on.
This will turn on the brake lights.

As described above, in this embodiment, the switch is actuated by the movement of the piston generated in the hydraulic pressure chamber of the master cylinder, so it is always linked to the braking point regardless of the adjustment of the brake pedal tread surface. You can turn on the brake lights.

In addition, both the movable and fixed contacts are housed inside the dust boot of the hydraulic master cylinder, which prevents rainwater and mud from entering from the outside and ensures reliable operation.Furthermore, in the unlikely event that the secondary cup Even in the event of damage and fluid leakage, the electrically conductive hydraulic fluid serves as a contact and the brake lamp lights up continuously, making it possible to detect an abnormal condition at an early stage.

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. be able to.

[Effect of idea]

As explained above, in the hydraulic master cylinder of the present invention, the tip of the push rod that pushes the piston inserted into the cylinder faces the opening of the cylinder, and the fixed contact of the switch circuit is placed at the mouth end of the opening. In addition, the push rod is provided with a movable contact that moves in the cylinder direction and comes into contact with the fixed contact as the push rod advances, so the structure is simpler and cheaper than conventional products.
Further, by adjusting the actuating members such as the brake pedal and the clutch lever, there is no deviation in the actuation timing of the switch, and the switch can always be actuated in accordance with the timing of pressurized fluid generation.

[Brief explanation of the drawing]

The figure is a partially sectional front view of a vertical hydraulic master cylinder. 1...Hydraulic pressure master cylinder, 2...Cylinder,
3... Cylinder body, 7... Large diameter hole, 10...
Piston, 11... Push rod, 11a...
Head, 13... Stopper, 14... Stopper plate, 15... Hydraulic pressure chamber, 17... Step portion, 18...
Synthetic resin plate, 19... Fixed contact, 20... Leaf spring, 21... Movable contact, 22... Brake lamp.

Claims (1)

[Scope of utility model registration request] A piston is movably inserted into the cylinder of a master cylinder, the tip of a push rod that pushes the piston faces into the opening of the cylinder, and pressure fluid is generated in the hydraulic pressure chamber of the cylinder by pushing the push rod. In the hydraulic master cylinder for a vehicle, a fixed contact of a switch circuit is disposed at the open end of the cylinder, and a movable contact is provided on the push rod so as to move toward the cylinder as the push rod moves forward and comes into contact with the fixed contact. A vehicle hydraulic master cylinder characterized by: