JPH0644781Y2 - Hydraulic master cylinder for brake - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a hydraulic master cylinder for a brake used for a rear wheel of a motorcycle or the like.

[Conventional technology]

For example, in a brake hydraulic master cylinder disclosed in Japanese Utility Model Laid-Open No. 61-35095, a hydraulic pressure generating piston fitted in a cylinder body is pushed by a push rod connected to a brake pedal, and a cylinder body is also used. A stop lamp switch is provided at the lower end of the push rod, and when the operator provided on the push rod moves in the piston pushing direction, the operator separates from the stop lamp switch and the stop lamp switch operates.

[Problems to be solved by the device]

However, in the above-mentioned structure, when an external force in the non-braking direction is applied to the brake pedal, the actuator provided on the push rod pushes the stop lamp switch, damaging the stop lamp switch or regulating the backward limit of the push rod. Therefore, the stopper plate provided on the cylinder body may fall off from the cylinder body.

Therefore, an object of the present invention is to provide a brake hydraulic master cylinder that does not damage the stop lamp switch or the cylinder body even if an external force in the non-braking direction is applied to the brake pedal.

[Means for Solving the Problems]

To achieve the above object, the present invention relates to a brake hydraulic master cylinder in which a piston for hydraulic pressure generation is inserted into a cylinder body equipped with a stop lamp switch and pushed by a push rod connected to the piston and a brake pedal. Between the piston and the push rod, an elastic member that normally biases the push rod in the piston direction and extends when the push rod moves in the anti-piston direction to allow separation between the push rod and the piston is provided, An actuator for operating the stop lamp switch is provided on the piston.

[Action]

With this configuration, the push rod pushes the piston during braking, and the stop lamp switch operates by the movement of the piston. Further, even if an external force in the non-braking direction is applied to the brake pedal, the elastic member extends and allows the push rod and the piston to be separated from each other.

〔Example〕

 Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a first embodiment of the present invention, in which a hydraulic master cylinder 1 for brake has a cylinder body 2 having a cylinder hole 3 opened downward, and a piston for generating a hydraulic pressure is formed in the cylinder hole 3. 4 is fluid-tightly and movably fitted to define a hydraulic chamber 5 between the upper bottom of the cylinder hole 3 and the piston 4.

The cylinder body 2 has a reservoir (not shown) on one side thereof.
A boss portion 7 for connecting the hose 6 from the vehicle body mounting brackets 8, 8 to the other side, and a connector 9 for connecting the hose 6 to the boss portion 7 and a stop lamp switch 10
The switch case 11 and the switch case 11 are fitted to each other, and the working fluid from the reservoir is supplied to the cylinder hole 3 through the relief port 12 and the supply port 13 formed in the boss portion 7.

The switch case 11 has a ring-shaped fitting portion 11a on the boss portion 7 at an upper portion, a positioning convex portion 11b that engages with a side wall of the cylinder body 2 at a side portion, and a storage portion 11c of the stop lamp switch 10 at a lower portion. And has a ring-shaped fitting portion 1 on the boss portion 7.
When the 1a is fitted, the stop lamp switch 10 is arranged below the side portion of the cylinder body 2.

Further, the switch case 11 has an actuator 1 on the top of the storage portion 11c.
An empty chamber 11d that allows the movement of 4 is formed, and a locking groove 11e of the dust boot 15 is formed on the side portion.

The actuator 14 includes a switch actuating piece 14b on an upper portion of a connecting portion 14a arranged along the storage portion 11c and a piston pushing piece 14c on a lower portion thereof.
Are bent in opposite directions, and the switch operating piece 14b is pressed against the stop lamp switch 10 by the spring 16 arranged in the empty chamber 11d.

The piston 4 inserted into the cylinder hole 3 has its backward limit regulated by a stopper 17 locked near the opening of the cylinder hole 3, and the lower end of the shaft portion 4a protruding from the cylinder body 2 is
The piston 4 is in contact with a push rod 19 connected to the brake pedal 18, and the piston 4 is pushed by the push rod 19 when the push rod 19 moves upward in the drawing due to the rotation of the brake pedal 18, so that the hydraulic chamber is pushed. A hydraulic pressure is generated in 5 to perform a braking action.

Also, below the shaft 4a of the piston 4, the shaft of the piston 4
A joint plate 21 that locks one end of a coil spring 20 arranged between the 4a and the push rod 19 is provided, and a switch plate is provided on the joint plate 21.
22 is externally fitted to the shaft portion 4a, and a return spring 23 for urging the piston 4 in the non-braking direction is arranged between the switch plate 22 and the stopper 17.

One end of the coil spring 20 is the joint plate.
21, the other end is locked to the push rod 19, respectively, and normally, the push rod 19 is urged to abut the piston 4, and the push rod 19 moves in the direction opposite to the piston 4 with a force equal to or greater than the set load. It sometimes expands to allow the push rod 19 to be separated from the lower end of the shaft portion 4a of the piston 4.

The switch plate 22 is a piston pushing piece of the actuator 14.
When the piston 4 comes into contact with 14c and moves in the braking direction, the actuator 14 is moved upward in the drawing,
The switch operating piece 14b is separated from the stop lamp switch 10 to operate the stop lamp switch 10.

With the above configuration, the piston 4 and the push rod 19 are separated from each other even when an external force in the non-braking direction is applied to the brake pedal 18, so that the stopper 17 and the stop lamp that restrict the backward limit of the piston 4 are stopped. The actuator 14 of the switch 10 is not affected by it, and the cylinder body 2 and the stop lamp switch 14 are not damaged.

2 shows the coil spring 20 of the first embodiment.
Instead of this, a second embodiment in which a U-shaped leaf spring 30 is arranged between the piston 4 and the push rod 19 is shown, which has the same effect as the first embodiment.

〔The invention's effect〕

As described above, in the present invention, in a brake hydraulic master cylinder in which a piston is pushed by a push rod connected to a brake pedal, the push rod is normally biased in the piston direction between the piston and the push rod. When the push rod moves in the direction opposite to the piston, an elastic member is installed that extends to allow the push rod and piston to separate from each other, and an actuator for activating the stop lamp switch is provided on the piston. Even if an external force in the braking direction is applied, the piston and push rod are separated from each other, and the stopper and stop lamp switch actuator that regulates the retreat limit of the piston are not affected and the cylinder body and stop lamp switch are damaged. Never.

[Brief description of drawings]

FIG. 1 shows a first example of a hydraulic master cylinder for brake according to the present invention.
FIG. 2 is a sectional front view showing an embodiment, and FIG. 2 is an enlarged view of a main part showing the second embodiment. 1 ... Brake hydraulic master cylinder, 2 ... Cylinder body, 3 ... Cylinder hole, 4 ... Piston, 10 ... Stop lamp switch, 14 ... Actuator, 18 ... Brake pedal, 19 ... Push rod, 20 ... Coil spring, 30 … Leaf springs

Claims (1)

[Scope of utility model registration request] 1. A hydraulic master cylinder for brake in which a piston for hydraulic pressure generation is fitted and inserted into a cylinder body having a stop lamp switch, and the piston is pushed by a push rod connected to a brake pedal. An elastic member is provided between the push rods, which normally biases the push rods in the piston direction and expands when the push rods move in the anti-piston direction to allow separation between the push rods and the pistons. A hydraulic master cylinder for brake, wherein an actuator for activating the above is provided on the piston.