JPH0642501U - Liquid sealing structure for reservoir tank for master cylinder - Google Patents

Abstract

(57) [Summary] [Purpose] Brake fluid is prevented from leaking out due to the problem of diaphragm clamping at the ventilation groove formed in the cap, and the brake fluid that passes through the diaphragm and reaches the air chamber is discharged from the ventilation groove. Suppress leaking. [Structure] A master cylinder reservoir tank divides a reservoir tank filled with brake fluid into a fluid chamber and an air chamber by a diaphragm. A ventilation groove communicating with the air chamber is formed in the cap that clamps the diaphragm edge on the diaphragm clamping end surface of the cap. In such a configuration, the ventilation groove forming portion of the cap is formed to be longer than the diaphragm sandwiching end face width to make the ventilation groove a long groove. Further, a packing covering the long groove was attached between the cap and the diaphragm.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a reservoir tank liquid sealing structure that is suitable for preventing leakage of brake fluid from a master cylinder reservoir tank.

[0002]

[Prior art]

 The master cylinder, which converts the brake operating force to hydraulic pressure, supplies and discharges the brake fluid filled in the reservoir tank to and from the cylinder pressure chamber. In the reservoir tank, pressure fluctuations occur due to changes in the volume due to the supply and discharge of brake fluid.To suppress this, a diaphragm that divides the reservoir tank into a fluid chamber and an air chamber is attached by a cap that is attached to the air chamber. Guides the atmosphere.

FIG. 5 is a plan view of a brake 1 attached to a handle for a motorcycle, a master cylinder is attached to the handle, and a brake lever 3 is rotatably attached to a lever bracket 2 attached to the master cylinder. , The rotation operation of the brake lever 3 is converted into the axial movement of the push rod of the master cylinder. The reservoir tank 4 in such a brake device is arranged above the master cylinder to supply and discharge the brake fluid to and from the master cylinder. A partial sectional view of a conventional reservoir tank 4 of this type is shown in FIG. The reservoir tank 4 is configured such that the upper surface of the tank body 6 filled with the brake fluid 5 is covered with a cap 7, and a diaphragm 8 that partitions the inside of the tank into upper and lower parts is attached. The diaphragm 8 is fixed by sandwiching its peripheral edge by the tank body 6 and the cap 7, and the ventilation groove 9 communicating with the outside is formed on the sandwiching surface on the cap 7 side in order to communicate the upper air chamber with the atmosphere. There is.

[0004]

[Problems to be solved by the device]

 However, in the structure of the conventional reservoir tank 4, since the ventilation groove 9 formed in the cap 7 is fixed to the diaphragm 8 while being overlapped with the end edge portion of the diaphragm 8, the shape of the ventilation groove 9 causes As shown in FIG. 6 (2), there is a problem that a gap 10 is formed between the tank main body 6 and the diaphragm 8 facing the ventilation groove 9, and the brake fluid 5 leaks from there. Further, the diaphragm 8 separates the inner part of the tank into a liquid chamber and an air chamber, but there is also a problem that the brake fluid permeates the diaphragm 8 and leaks from the air chamber to the outside through the ventilation groove 9.

The present invention focuses on the above-mentioned conventional problems, and prevents the brake fluid from leaking out due to the problem of the diaphragm being clamped in the ventilation groove portion formed in the cap, and at the same time, it permeates the diaphragm to allow the air chamber to pass through. It is an object of the present invention to provide a liquid sealing structure for a master cylinder reservoir tank that makes it difficult for the brake fluid reaching the above to leak out from the ventilation groove.

[0006]

[Means for Solving the Problems]

 In order to achieve the above object, the liquid sealing structure of the master cylinder reservoir tank according to the present invention is such that the diaphragm tank is sandwiched between the liquid chamber and the air chamber while the inside of the reservoir tank filled with the brake fluid is partitioned by the diaphragm. In a master cylinder reservoir tank in which a cap is attached, and a ventilation groove communicating with the air chamber is formed on the diaphragm clamping end surface of the cap, the ventilation groove forming portion of the cap is formed to be longer than the diaphragm clamping end surface width. The ventilation groove is a long groove, and a packing for covering the long groove is attached between the cap and the diaphragm.

[0007]

[Action]

 According to the above configuration, the diaphragm is sandwiched between the tank and the cap, but the cap sandwiches the diaphragm through the packing. As a result, the ventilation groove formed in the cap directly faces the packing, and the cap side clamping surface of the diaphragm is pressed by the packing even at the ventilation groove portion. For this reason, the diaphragm does not float up to the tank side in the ventilation groove portion, and the leakage space of the brake fluid does not occur. Further, since the ventilation groove is formed longer than the sandwiching end face width of the diaphragm, the ventilation resistance of the brake fluid particles that have permeated the diaphragm becomes large, which makes it difficult for the permeated brake fluid to leak from the ventilation groove.

[0008]

【Example】

 Hereinafter, a specific embodiment of the liquid sealing structure of the master cylinder reservoir tank according to the present invention will be described in detail with reference to the drawings.

1 and 2 are a side sectional view and an exploded perspective view of a main part of a reservoir tank 20 according to an embodiment. As shown in the figure, the reservoir tank 20 has a tank body 24 filled with the brake fluid 22, and a cap 26 is attached to the upper surface of the tank body 24. In order to suppress the pressure fluctuation inside the tank 20, a diaphragm 28 is attached, which divides the inside of the tank 20 into a liquid chamber 30 and an upper air chamber 32.

The diaphragm 28 is provided with a flange 33 that engages with the upper end surface of the side wall of the tank body 24, and the flange 33 can be pressed and fixed by the cap 26 from the upper surface side. Further, a bellows portion 34 is formed on the diaphragm 28 so as to absorb pressure fluctuations, and three bellows portions are formed along the inner peripheral surface of the side wall of the tank body 34. The height of the upper end surface of the bellows portion 34 is set to be at the same height position as the flange 33.

On the other hand, the cap 26 is formed with a sandwiching surface 36 with respect to the flange 33 of the diaphragm 28, and at the same time, is provided with pawls 38 and 40 for pressing and positioning the inner and outer end edges of the flange 33. The inner claw 38 has a protruding length longer than that of the outer claw 40 to hold the diaphragm 28 against the inner wall surface of the tank body 24. Further, the cap 26 is formed with an air passage 42 for keeping the air chamber 32 in the tank at atmospheric pressure. In order to form the ventilation groove 42, a land portion 44 is formed on the inner surface of the cap 26 so as to be flush with the sandwiching surface 36 and project toward the center. The land portion 44 is further projected from the position where the inner claw 38 is formed, and reaches the length facing the two lines of the bellows portion 34 of the diaphragm 28. Then, the ventilation groove 42 is formed in the land portion 44 to communicate the outside with the air chamber 32 to introduce the atmospheric pressure.

In the reservoir tank 20 of this embodiment, when the diaphragm 28 is clamped by the cap 26, the packing 46 is interposed between the clamping surface 36 and the flange 33. The packing 46 has the same shape as the flange 33 and the sandwiching surface 36 of the cap 26. However, as shown in FIG. 3, a face-to-face joining portion 48 to the land portion 44 of the cap 26 is formed. There is. The packing 46 is laminated on the upper surface of the flange 33 of the diaphragm 28 and is fixedly held by the sandwiching surface 36 of the cap 26, but the joint portion 48 joined to the land portion 44 is the bellows portion 34 of the diaphragm 28. It is pressed and held from below. Therefore, the ventilation groove 42 becomes a long groove and opens on the center side of the air chamber 32.

In the reservoir tank 20 configured in this way, as shown in FIG. 4, in the cross section of the tank side wall portion, the flange 33 of the diaphragm 28 is pressed by the holding surface 36 of the cap 26 with the packing 46 in between. Therefore, the diaphragm flange 33 does not directly face the ventilation groove 42. As a result, the entire circumference of the flange 33 is sandwiched by the packing 46, which prevents the flange 33 from floating toward the ventilation groove 42. Therefore, it is possible to prevent a gap that communicates with the outside from being generated between the flange 33 and the tank body 24, and it is possible to reliably prevent the brake fluid 22 from leaking from the fluid chamber 30. Further, although the ventilation groove 42 is made long by the land portion 44 formed on the cap 26, the land portion 44 is also sealed by the facing joint portion 48 of the packing 46, and the joint state by the bellows portion 34 of the diaphragm 28. Retained. Therefore, the opening of the ventilation groove 42 to the air chamber 32 becomes the tip of the land portion 44, and the length of the ventilation groove 42 can be increased. The brake fluid 22 becomes fine particles when it passes through the diaphragm 28 and exists in the air chamber 32. However, the ventilation groove 42 of the embodiment is defined by the packing 46 so that the ventilation passage length becomes longer, and thereby the ventilation resistance is increased. Since the resistance is increased, the leakage of the permeated brake fluid can be suppressed as much as possible.

As described above, in the liquid sealing structure for the master cylinder reservoir tank according to the embodiment, when the diaphragm 28 is sandwiched by the cap 26, the packing 46 is interposed between the diaphragm 28 and the diaphragm flange on the ventilation groove 42 side. 33 is prevented from floating, and the ventilation resistance is increased by setting the ventilation groove 42 to be longer than the diaphragm sandwiching width, so that the leakage of brake fluid can be effectively suppressed. It will be possible.

[0015]

[Effect of device]

 As described above, according to the present invention, the inside of a reservoir tank filled with brake fluid is divided into a fluid chamber and an air chamber by a diaphragm, and a cap for sandwiching the diaphragm edge is attached to the ventilation groove communicating with the air chamber. In a reservoir tank for a master cylinder in which the cap is formed on the diaphragm clamping end surface, the cap ventilation groove forming portion is formed to be longer than the diaphragm clamping end surface width to make the ventilation groove long. Since a packing that covers the long groove is attached between the diaphragm and the diaphragm, the brake fluid is prevented from leaking out due to the diaphragm not being clamped in the ventilation groove formed in the cap, and it also permeates the diaphragm. The effect is that the brake fluid that reaches the air chamber can be made difficult to leak from the ventilation groove.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional side view of a reservoir tank having a liquid sealing structure according to an embodiment.

FIG. 2 is an exploded perspective view of the same.

FIG. 3 is a plan view showing the inner surface of the cap and a plan view of the packing.

FIG. 4 is a cross-sectional view of a tank side wall portion and a land portion in a ventilation groove portion.

FIG. 5 is a plan view of a motorcycle brake unit.

FIG. 6 is a partial cross-sectional view and a side view of a main part of a conventional reservoir tank.

[Explanation of symbols]

 20 Reservoir Tank 22 Brake Fluid 24 Tank Main Body 26 Cap 28 Diaphragm 30 Liquid Chamber 32 Air Chamber 33 Flange 34 Bellows Part 36 Clamping Surface 38 Inner Claw 40 Outer Claw 42 Ventilation Groove 44 Land Part 46 Packing 48 Land Face-to-Face Joint

Claims (1)

[Scope of utility model registration request] 1. A cap for sandwiching a diaphragm end edge while partitioning a reservoir tank filled with brake fluid into a liquid chamber and an air chamber by a diaphragm, and a ventilation groove communicating with the air chamber is provided with a diaphragm of the cap. In the master cylinder reservoir tank formed on the sandwiching end face, the ventilation groove forming portion of the cap is formed longer than the diaphragm sandwiching end face width to make the ventilation groove a long groove, and between the cap and the diaphragm. A liquid sealing structure for a reservoir tank for a master cylinder, which is equipped with a packing that covers the long groove.