JPH0143346Y2 - - Google Patents

Description

[Detailed explanation of the invention] This invention relates to a master cylinder used in hydraulic brakes. Specifically, this invention is a master cylinder in which a reservoir tank for storing brake fluid is fitted into the upper part of the cylinder body that houses a piston. Concerning cylinder improvement.

Conventionally, master cylinders of the above type have been known in which a tubular portion protruding approximately vertically from the bottom of the reservoir tank is fitted into a tank mounting hole at the top of the cylinder body via a grommet seal.

The tubular portion is originally intended to allow the brake fluid in the reserve tank to flow down into the cylinder body, but it is also used not only as a flow path but also as a fixing means for fixing the reservoir tank to the cylinder body as described above. If it is made to function, there is no need to specially form engagement means between the cylinder body and the reservoir tank, and it becomes possible to simplify the mutual structure of the cylinder body and the reservoir tank.

By the way, the brake fluid is injected into the reservoir tank by vacuum filling after it is attached to the cylinder body in order to prevent air from entering the reservoir tank.
Therefore, a cylindrical brake fluid inlet is formed protruding from the upper part of the reservoir tank in order to facilitate the vacuum filling operation.

Normally, the brake fluid inlet is formed to protrude vertically in accordance with the direction in which the tubular part is fitted, but recently it has also been formed to protrude and be inclined forward, etc. with respect to the fitting direction of the tubular part. I started to get angry. By tilting it forward, etc.
This is because there are many cases where the limited installation space of a vehicle body or the like can be used more effectively and maintainability can also be improved.

However, a master cylinder in which the brake fluid inlet is formed to protrude at an angle is more likely to cause problems such as fluid leakage during vacuum filling than a master cylinder in which the brake fluid inlet is formed to protrude vertically. This is a tilted version.
During the vacuum filling operation, the force that presses the filling device against the brake fluid inlet has a component that tends to move the reservoir tank itself in a direction perpendicular to the fitting direction of the tubular part, and this component causes the connection between the tubular part and the tank mounting hole. This is because the grommet seal interposed between the parts is deformed and the sealing effect is reduced.

This problem can be solved by increasing the strength of the connection between the cylinder body and the reservoir tank using fastening means such as bolts, but using fastening means such as bolts increases the effort required when installing the reservoir tank. However, the ease of assembly is impaired.

This idea was made in view of the above circumstances,
The reservoir tank is fixed to the cylinder body by fitting the tubular part provided at the bottom of the reservoir tank into the tank mounting hole of the cylinder body via a grommet seal, and the brake fluid in the reservoir tank is The master cylinder is provided with an injection port inclined with respect to the fitting direction of the tubular part, and when the brake fluid is injected into the reservoir tank, the reservoir tank is moved into the tubular part by a force acting on the reservoir tank. It is possible to restrict the movement of the reservoir tank in a direction perpendicular to the fitting direction of the reservoir tank, and furthermore, it is possible to restrict the movement of the reservoir tank without using a fastening means that takes time and effort to install. Therefore, the workability of installing the reservoir tank is improved. It is an object of the present invention to provide a master cylinder that can prevent the grommet seal from deforming without damaging the grommet seal, thereby preventing the occurrence of liquid leakage, etc.

This invention, as a means to achieve the above objectives,
A regulating wall protruding in the vertical direction is provided either at a position on the periphery of the tank mounting hole of the cylinder body that is forward in the direction of brake fluid injection, or at a predetermined position on the reservoir tank corresponding to the position, and at the other side. provided with a contact surface that contacts the regulation wall from the brake fluid injection direction.

Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 1 is a cross-sectional view of a master cylinder according to an embodiment, viewed from the side, and in the figure, 1 indicates a cylinder body, and 2 indicates a reservoir tank.

The cylinder body 1 is equipped with a piston 3 for generating hydraulic pressure therein, and a pair of tank mounting holes 5 are formed by a pair of boss parts 4 projecting almost vertically in the upper part, and a pair of tank mounting holes 5 are formed in the upper part. At the bottom of the hole 5, passages 6 and 7 communicating with the piston 3 are bored.

The reservoir tank 2 is connected to the cylinder body 1.
It stores brake fluid to be supplied to the cylinder body, and has a tubular part 8 projecting almost vertically at the bottom thereof through which the brake fluid flows down toward the cylinder body 1, and a cylindrical brake fluid inlet 9 at the top. is the front (first
It is formed to protrude and incline to the left (in the figure). A cap 10 for closing the brake fluid injection port 9 is detachably attached to the tip of the brake fluid injection port 9.

The master cylinder shown in FIG. 1 is of a type in which the reservoir tank 2 is fixed to the cylinder body 1 by fitting the tubular portion 8 into the tank mounting hole 5 via a grommet seal 11. In order to prevent the mutually fitted members from coming off, a protrusion 4a is formed on the inner circumference of the boss portion 4, and a protrusion 4a is formed on the outer circumference of the grommet seal 11 to engage with the protrusion 4a. A groove 11a is formed to
A protrusion 8a that engages with the lower end surface of the grommet seal 11 is formed at the tip of the tubular portion 8.
Furthermore, in order to restrict the movement of the reservoir tank 2 during brake fluid injection, a restriction wall 12 that protrudes upward is formed at a predetermined position on the upper end of the boss portion 4, and the restriction wall 12 is connected to the corresponding reservoir tank 2. Contact surfaces 13 and 14 that contact the regulation wall 12 are provided at the bottom.
It is formed.

As shown in FIG. 2, the regulating wall 12 is provided at the periphery of the tank mounting hole 5 at a position forward of the brake fluid injection direction (direction indicated by arrow A in FIG. 1). , is curved along the periphery of the tank mounting hole 5. On the other hand, the contact surface 13,
14, as shown in FIG. 3, are formed at the front ends of step portions 15 and 16 from which the regulating wall 12 protrudes so as to abut against the regulating wall 12 from the brake fluid injection direction A, respectively. The radius of curvature is set smaller than that of the regulating wall 12.

The dimensions of the stepped portions 15 and 16 are set so that a distance C remains between the stepped portions 15 and 16 and the upper end surface of the regulating wall 12.

With this structure, even if a pressing force of a magnitude F is applied in the direction of arrow A in FIG. component in the direction
F ₁ is the above-mentioned regulating wall 12 and contact surfaces 13 and 14.
The restriction wall 12 is supported by the abutting of the reservoir tank 2, thereby restricting movement of the reservoir tank 2 in the direction of the component _F1 . Furthermore, if the movement of the reservoir tank is restricted by the restriction wall 12 in this manner, there will be no problem in the installation work of the reservoir tank 2. Therefore, it is possible to prevent the grommet seal 11 from deforming without reducing the workability of installing the reservoir tank 2, thereby improving the durability of the grommet seal 11 and preventing the occurrence of liquid leakage, etc. It became like that.

In the above embodiment, the regulating wall 12 is provided on the cylinder body 1, and the contact surfaces 13 and 14 are provided on the reservoir tank 21, but the point is that the movement of the reservoir tank 2 during brake fluid injection is It is sufficient if the restriction can be restrained, and it is also possible to provide the regulating wall 12 on the reservoir tank 2 side and the contact surfaces 13 and 14 on the cylinder body side.

As explained above, in the master cylinder of the present invention, for example, the cylinder body is provided with a regulating wall that protrudes upward, and the reservoir tank, which is fitted and attached to the cylinder body from above, is provided with the regulating wall from the direction in which brake fluid is injected. In this structure, the movement of the reservoir tank in the direction perpendicular to the fitting direction is restricted by the restriction wall without particularly using a fastening means such as a bolt. Therefore, it is possible to prevent deformation of the grommet seal interposed in the fitting part of the reservoir tank without reducing the workability of installing the reservoir tank, improving the durability of the grommet seal and preventing the occurrence of liquid leakage, etc. It is now possible to prevent

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of an embodiment of the present invention, FIG. 2 is a view of the boss portion in FIG. 1, and FIG. 3 is a view of the tubular portion in FIG. 1. 1...Cylinder body, 2...Reservoir tank,
3... Piston, 4... Boss part, 5... Tank mounting hole, 8... Tubular part, 9... Brake fluid inlet, 11... Grommet seal, 12... Regulation wall, 13, 14... Contact surface, 15, 16... step portion.

Claims (1)

[Scope of utility model registration request] a reservoir tank that is attached to the top of the cylinder body housing the piston and stores brake fluid to be supplied into the cylinder body;
and a cylindrical brake fluid inlet that projects upwardly at an angle with respect to the projecting direction of the tubular part, and the reservoir tank is attached to the tank on the upper part of the cylinder body through a grommet seal. In a master cylinder that is fixed to a cylinder body by fitting into a hole, the periphery of the tank mounting hole of the cylinder body at a position forward with respect to the brake fluid injection direction of the master cylinder, or the periphery of the reservoir tank. A master cylinder characterized in that a regulating wall protruding in the vertical direction is provided at one of the positions corresponding to the above, and a contact surface that contacts the regulating wall from the brake fluid injection direction is provided at the other end.