JPH11105698A - Master cylinder - Google Patents

Abstract

(57) [Summary] [PROBLEMS] A stopper pin for opening and closing a center valve of a master cylinder used for a brake device of an automobile,
Avoid falling off the cylinder body. A boss portion (2a) serving as an attachment portion of a reservoir tank (2) to a cylinder body (1) allows a hydraulic fluid to flow from the reservoir tank (2) to the cylinder body (1), and a stopper pin (23).
Stopper 2 that regulates when the movement of the object exceeds a predetermined amount
4 was mounted by press-fitting so that the position could be changed by utilizing the elasticity of the claws 24b. When the stopper pin 23 is loosened and is about to come off, the upper end of the stopper pin 23 is
a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a master cylinder connected to a hydraulic brake or the like in a vehicle such as an automobile.

[0002]

2. Description of the Related Art A master cylinder converts a pedaling force applied to a brake pedal into a hydraulic pressure, and guides the hydraulic pressure to a cylinder mechanism of a drum brake or a disc brake on a wheel side to perform a braking action. The vehicle has two brake systems, one for the front wheels and the other for the rear wheels. Each system has an independent hydraulic pressure supply circuit, so the master cylinder slidably houses two pistons in the cylinder body. Tandem structure.

An outline of a tandem type master cylinder will be described with reference to FIG. Reference numeral 1 denotes a cylinder main body, and reference numeral 2 denotes a reservoir tank provided at an upper portion thereof, which is connected to a first reservoir port 3 and a second reservoir port 4 of the cylinder main body 1. The cylinder body 1 is provided with an input port 5 and a compensation port 6 on the first reservoir port 3 side, and an input port 7 on the second reservoir port 4 side.
The working fluid (fluid) in the reservoir tank 2 is introduced into the supply chambers 8 and 9 respectively. Reference numeral 10 denotes a pressure chamber.

[0004] The cylinder body 1 is provided with a first connection port 11 (not shown in the figure) facing the other side of the drawing at the center, and a second connection port 12 facing upward at the left end in the figure. Is provided. The first connection port 11 is connected to the brake device for the rear wheel, and the second connection port 12 is connected to the brake device for the front wheel, so that the pressurized hydraulic fluid is sent to each brake device. I have.

[0005] A first piston 13 and a second piston 14 are slidably fitted into the interior of the cylinder body 1 through seal members 15 and 16.
When the push rod (not shown) of the booster whose tip fits into the recess 13a formed at the left side moves to the left in the figure, it moves to the left to push the hydraulic fluid introduced from the reservoir tank 2, The first connection port 11 and the second connection port 12 supply the brake devices for the rear wheels and the front wheels.

A screw hole 13b is formed in the center of the first piston 13 on the side opposite to the concave portion 13a, and a tip portion 17a is provided in the screw hole 13b so as to face the second piston 14. The base of the pin-shaped stem 17 is screwed. The head 17a of the stem 17 passes through a hole 18a at the bottom of the funnel-shaped sheet 18, and when the first piston 13 approaches the second piston 14, the sheet 18
It is designed to progress inside. 18b is a hole provided in the sheet 18 so that the hydraulic fluid flows. Sheet 1
8 and a seat plate 19 provided on the first piston 13 side
A first spring 20 is interposed between the first piston 20 and the first piston 1 with respect to the second piston 14.
3 applies a force in the direction in which it moves away.

A concave portion 14a is formed at the end of the second piston 14.
When the stem 17 advances toward the second piston 14 while being supported by the seat 18, the head 17a and the vicinity thereof are housed. 14 b is a hole provided in the second piston 14.

A seat plate 19 is attached to the second piston 14 by engagement. A second spring 20 is interposed between the seat plate 19 and the innermost portion of the cylinder body 1 in a compressed state. Have been. Thus, a force toward the first piston 13 is applied to the second piston 14. The second piston 14 is provided with a center valve 21.
The opening / closing rod 22 opens and closes. Reference numeral 23 denotes a stopper pin, the lower end of which is inserted into the cylinder body 1, which receives the base end of the opening / closing rod 22 and regulates its position.

The operation of the master cylinder thus configured will be described. When the driver depresses a brake pedal (not shown) and the push rod of the booster pushes the first piston 13 leftward in the drawing, the first piston 13 compresses the spring 20 and moves leftward. I do. This movement causes the compensation port 6 to move to the first piston 13
The pressure of the hydraulic fluid in the supply chamber 8 is increased due to the blockage by the connection port 11, and the hydraulic fluid is supplied from the connection port 11 to the rear wheel brake device.
Activate the rear wheel brake.

When the pressure in the supply chamber 8 increases, the hydraulic fluid moves the second piston 14 against the spring 20 to the left in the drawing. This movement causes the opening / closing rod 22
Is moved away from the stopper pin 23, the center valve 21 is closed, and the hydraulic fluid in the pressurizing chamber 10 is pressurized and transferred from the connection port 10 to the brake device for the front wheels. Thereby, the brake device for the front wheels also operates.

The center valve 21 is connected to the second piston 14
The valve opens to receive the hydraulic fluid when the pressurizing side is not operated, and closes to close the hydraulic fluid on the pressurizing side when activated. The opening and closing operation of the center valve 21
A rod 22 linked to a center valve 21 is attached to a stopper pin 23 provided so as to bridge the inside of the cylinder body 1.
When the second piston 14 is moved by receiving hydraulic pressure, the rod 22 is separated from the stopper pin 23 to close the valve (see Japanese Patent Application Laid-Open No. Hei 8-91202). Gazette).

Stopper pin 23 provided for the above purpose
Is provided in the mounting portion of the reservoir tank 2 to the cylinder main body 1 because of its function. There was a risk of falling inside. In order to solve this problem, in the invention described in the above-mentioned publication, a portion called a horizontal web is formed in the boss portion on the reservoir tank side so as to press the upper end of the stopper pin. Apart from this, there is also a structure in which unevenness is provided on a metal plate and this is placed in a boss portion of a reservoir tank.

[0013]

However, in these structures, in order to cope with the case where the mounting height of the reservoir tank is different from the master cylinder, the size of the horizontal web, the thickness of the metal plate, or the unevenness of the metal plate are required. It is necessary to change the size, the length of the stopper pin, and the like, and there is a problem that one type of member cannot cope with many models having different dimensions. In the case of using a metal plate,
If the metal plate has small irregularities, there is a possibility that the flow of the hydraulic fluid (brake fluid) is hindered.

The present invention has been made in view of the above, and an object of the present invention is to provide a master cylinder that reliably prevents a stopper pin from falling off and that does not cause any trouble in the flow of hydraulic fluid.

[0015]

According to the present invention, as a means for solving the above-mentioned problems, in the invention described in claim 1, a stopper is provided for providing a piston with a center valve and controlling opening and closing of the center valve. In a master cylinder provided with a pin inserted through a hole in the cylinder body, the stopper pin is prevented from coming off from the cylinder body by a stopper that is detachably provided on a boss part that is an attachment part of the reservoir tank to the cylinder body. It is characterized in that it is performed.

According to the second aspect of the present invention, in the first aspect, the height of the stopper is adapted to several types of cylinder bodies having different boss portions of the reservoir tank. It is characterized in that it is set to a possible value.

With such a structure, the stopper restricts the movement of the stopper pin by a predetermined amount or more. Therefore, even when the reservoir tank side is in the posture of being upward during manufacturing or transportation, the stopper pin does not abut against the stopper and enter the reservoir tank. Since the stopper allows the flow of the hydraulic fluid, it does not hinder the braking action. By changing the fitting depth of the stopper to the boss portion of the reservoir tank, it is possible to directly correspond to master cylinders of a plurality of vehicle types.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. In the present invention,
Hydraulic fluid is allowed to flow from the reservoir tank 2 to the cylinder body 1 to the boss 2a serving as a mounting portion of the reservoir tank 2 to the cylinder body 1, and the stopper pin 23 is loosely fitted and moves. A stop 24 for restricting when the amount becomes equal to or more than a fixed amount is attached by press-fitting so that the position can be changed.

2 to 4 show the stopper 24 as a single unit. FIG. 2 shows a plan view, FIG. 3 shows a front view, and FIG. 4 shows a bottom view. The stopper 24 has a structure in which three first claws 24b are erected at equal intervals on a substrate 24a having a circular shape in a plan view, and a projection 24c which is lower than the claw 24b is erected therebetween. As shown in FIG. 3 and FIG.
On the lower surface of 4a, three projections 24d are provided at equal intervals so as to face the upper surface of the cylinder body 1.

The stopper 24 having the above structure is used for the cylinder body 1.
Boss 2a of the reservoir tank 2 at a stage before coupling to
Is fitted from below. When the stopper 24 is made of a synthetic resin, if an external force is applied from below in the figure, the elasticity causes the claw 24b to be deformed inward and fit into the boss 2a. If the external force is removed after the fitting, it is connected to the boss 2a by friction. The protrusion 24c is provided in the boss 2a.
Port is blocked. Claw 24 of stopper 24
By appropriately setting the height dimension H of b (see FIG. 3), it is possible to adapt to several types of cylinder bodies in which the depth of the boss portion 1a of the reservoir tank 1 is different.

The master cylinder thus configured has the same function as that of FIG. That is, the hydraulic fluid from the reservoir tank 2 is supplied from above the stopper 24 as shown by an arrow A in FIG.
b, flows to the outer periphery of the substrate 24a,
This is because it enters the supply chamber 9 through 4d. Even if the height of the boss portion 2a of the reservoir tank 2 attached to the cylinder body 1 changes, if the height H of the claw 24b is sufficiently large, it can be handled as it is. When the master cylinder is manufactured or transported, the reservoir tank 2 side is lowered, and the stopper pin 23 receives vibration in this state.
Even if the support is loosened, the upper end of the stopper pin 23 comes into contact with the lower surface of the substrate 24a of the stopper 24, so that there is no possibility that the stopper pin 23 falls into the reservoir tank 2 unlike the conventional one.

In the above-described embodiment, a so-called tandem type master cylinder in which first and second two pistons are provided inside a cylinder body is described. However, the present invention is not limited to this. Instead, a type having only one piston may be applied as long as it has a stopper pin.

[0023]

As described above, the present invention is a master cylinder in which a stopper pin drop-out prevention mechanism is improved as described above. Therefore, according to the first aspect of the present invention, the stopper pin is provided during manufacturing or transportation. It is possible to reliably prevent a situation in which the device falls off. Also, due to the structure of the stopper,
There is no hindrance to the flow of the hydraulic fluid. And Claim 2
According to the invention described in (1), one type of stopper can be used for a plurality of types of reservoir tanks having different boss portions.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view showing a main part of an embodiment of the present invention.

FIG. 2 is an enlarged plan view showing a stopper in FIG. 1;

FIG. 3 is a front view of the one in FIG. 2;

FIG. 4 is a bottom view of that of FIG.

FIG. 5 is a sectional view showing an example of the structure of a master cylinder.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylinder main body 2 Master cylinder 2a Boss part 13 1st piston 14 2nd piston 21 Center valve 23 Stopper pin 24 Stopper

Claims (2)

[Claims] In a master cylinder having a piston provided with a center valve and a stopper pin for controlling opening and closing of the center valve inserted through a hole of the cylinder body, the stopper pin is prevented from coming off from the cylinder body by a reservoir tank. A master cylinder characterized in that the operation is performed by a stopper which is detachably provided on a boss portion serving as a mounting portion to the cylinder body. 2. The master cylinder according to claim 1, wherein the height dimension of the stopper is set to a value that can be adapted to several types of cylinder bodies having different depths of the boss portions of the reservoir tank. .