JPS6238434Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a brake booster, and more particularly to a brake booster that supplies positive pressure to a variable pressure chamber of the brake booster.

Conventionally, as a brake booster, compressed air as a positive pressure is supplied to a variable pressure chamber of the brake booster, and atmospheric pressure or negative pressure is supplied to a constant pressure chamber, and the pressure difference between the positive pressure and the atmospheric pressure or negative pressure is A device that operates a power piston is known. In this type of brake booster, the absolute pressure value of positive pressure can be made much larger than that of negative pressure, so the diameter of the power piston is kept small, that is, the brake booster is made larger. This has the advantage that it is possible to increase the output without causing any problems.

By the way, this type of brake booster is usually equipped with a tank for accumulating compressed air, but in the past, the tank was provided separately from the brake booster, so the brake booster In addition to securing the installation space, it is also necessary to secure the installation space for the tank, and as a result, even if the brake booster can be made smaller, it is not always easy to secure the space. Also, since the tank and brake booster are separate,
Connection work was required to connect the two.

In view of these circumstances, the present invention has been developed by installing a tank integrally on the master cylinder installation side of the shell of the brake booster, which makes it easier to secure the installation space for the tank, and also makes it possible to easily secure the installation space for the tank. The present invention provides a brake booster that allows easy connection work and allows the tank to be used as a reinforcing member for the shell.

The present invention will be explained below with reference to the illustrated embodiments.
In FIG. 1, 1 is a front shell, 2 is a rear shell, and a power piston 3 and a diaphragm 4 stretched over the rear surface of the power piston 3 are provided in a sealed container composed of both shells 1 and 2.
The power piston 3 and the diaphragm 4 partition the inside of the shells 1 and 2 into a constant pressure chamber 5 at the front and a variable pressure chamber 6 at the rear. A valve body 7 is integrally provided on the shaft portion of the power piston 3, and in the illustrated embodiment, this valve body 7 closes a cylindrical main body portion 9 housing a valve mechanism 8 for switching a fluid circuit and an opening at its right end. It is composed of a lid body 10 and a hub 12 that slidably holds the base of a push rod 11 serving as an output shaft, and between the cylindrical body portion 9 and the hub 12, the inner periphery of the power piston 3 and the diaphragm 4 is The two are integrally connected by bolts 13 with their parts sandwiched together. The power piston 3, valve body 7, etc. are normally held in the non-operating position shown in FIG. 1 by a return spring 14.

The valve mechanism 8 includes a first valve seat 15 formed on the cylindrical main body 9 and a second valve seat 1 formed on the valve plunger 16.
7 and both valve seats 15 and 17 are provided with a valve body 18 that is seated from the right side in FIG. The valve plunger 16 is connected to an input shaft 20 that is linked to a pedal, and the distal end surface of the valve plunger 16 faces the other end surface of a reaction disk 21, which is disposed with one end surface facing the base end surface of the push rod 11. .

The outer peripheral portion of the first valve seat 15 is communicated with the constant pressure chamber 5 through a passage 25 formed in the valve body 7, and this constant pressure chamber 5 is connected to the intake through a negative pressure introduction hole 26 provided in the front shell 1. It is connected to a negative pressure source such as a manifold. The push rod 11 penetrates the seal member 27 and projects to the outside of the front shell 1, and is linked to a piston 30 of a master cylinder 29 attached to the front shell 1 with a bolt 28, and the seal member 27 is connected to a constant pressure chamber. 5. Maintains airtightness.

On the other hand, an intermediate portion between the first valve seat 15 and the second valve seat 17 communicates with the variable pressure chamber 6 via a passage 31 provided in the valve body 7. The variable pressure chamber 6 is kept airtight by a seal member 32 that slidably passes through the cylindrical main body portion 9.

Further, the inner circumferential portion of the second valve seat 17 is communicated with a pressure chamber 35 formed in the cylindrical main body portion 9 constituting the valve body 7, and this pressure chamber 35 is connected to the lid body 1.
0, a flexible hose 37 that is spirally wound around the outer periphery of the cylindrical main body 9 and then extended along the outer periphery of the shells 1 and 2 toward the master cylinder 29, and the connector 38. It communicates with a tank 39 provided in the front shell 1. The pressure chamber 35 is isolated from the atmosphere by a seal member 40 provided between the lid 10 and the input shaft 20, and the portion of the flexible hose 37 wound around the cylindrical main body 9 is It is housed and protected within a cover 41 attached to the rear shell 2.
A slit 42 is formed in the right end of the cover 41 in the vertical direction, and a clevis (not shown) and a brake pedal that interlock the input shaft 20 and the brake pedal enter into the slit 42 and the cover 41 is opened.
This prevents it from coming into contact with 1.

However, the tank 39 provided in the front shell 1 is arranged by utilizing the space between the front shell 1 and the reservoir 45 of the master cylinder 29, and the positive pressure introduction provided in the tank 39 is It is communicated via a pipe 46 with a positive pressure source such as an air compressor (not shown). In this embodiment, a radially intermediate portion 1 of the front shell 1 that does not come into contact with the power piston 3 described above is used.
The volume of the tank 39 is secured by bulging out in a ring shape toward the power piston 3 side.

At the same time, a portion 1b outside the radial intermediate portion 1a is a cylindrical portion 3 formed on the outer periphery of the power piston 3 so as to protrude toward the master cylinder side from the front shell of a normal brake booster.
The length of a is made long so that the folded portion 4a of the diaphragm 4 is located on the cylindrical portion 3a. If the folded part 4a of the diaphragm 4 is positioned above the cylindrical part 3a of the power piston 3 in this way, when pressure is applied to the diaphragm 4, the cylindrical part 3a is shorter than the folded part 4a. The folded portion 4a can be prevented from bulging out toward the constant pressure chamber 5 to have a spherical cross section, and the durability of the diaphragm 4 can be improved.

In the above configuration, compressed air from a positive pressure source (not shown) is introduced into the tank 39 of the brake booster through the positive pressure introduction pipe 46 and stored therein, and the compressed air in the tank 39 is supplied to the tank 39 through the connector 38 and the compressed air. Pressure chamber 3 via flexible hose 37 and connector 36
It has been introduced in 5. When the brake pedal (not shown) is depressed to move the input shaft 20 and the valve plunger 16 to the left, the valve body 18 seats on the first valve seat 15 and cuts off communication between the variable pressure chamber 6 and the constant pressure chamber 5. At the same time, the valve body 18 touches the second valve seat 17
Since the pressure chamber 35 and variable pressure chamber 6 are communicated with each other, the compressed air in the pressure chamber 35 is supplied into the variable pressure chamber 6, and the power piston 3 is moved around the front and back of the power piston 3, similar to a conventionally known brake booster. The pressure difference causes the power piston 3 to move forward against the elastic force of the return spring 14. As a result, the push rod 11 advances the piston 30 of the master cylinder 29 to perform a braking action.

When the force on the brake pedal is released from this brake operating state, the valve body 18 of the valve mechanism 8 seats on the second valve seat 17 to cut off communication between the variable pressure chamber 6 and the pressure chamber 35, and the valve body 18 on the first valve seat Since the power piston 3 is separated from the power piston 15 and communicates the variable pressure chamber 6 with the constant pressure chamber 5, the power piston 3 is returned to its original non-operating position by the return spring 14.

In this embodiment, since the tank 39 is provided between the front shell 1 and the reservoir 45 of the master cylinder 29, not only is no special space required for providing the tank 39, but the tank and brake booster are This has the advantage that it is lighter and can be manufactured at a lower cost than when the device is configured separately. Furthermore, since the flexible hose 37 can be connected when assembling the brake booster, it is possible to save the effort of connecting the tank and the brake booster when installing the brake booster to the vehicle body. Furthermore, since the tank 39 also serves as a reinforcing plate for the front shell 1, there is no need to provide a separate reinforcing plate for the front shell 1, or the thickness of the front shell 1 can be made thinner.

Figure 2 shows another embodiment of the present invention.
In this embodiment, a flexible hose 50 corresponding to the flexible hose 37 is disposed within the constant pressure chamber 5. One end of this flexible hose 50 is connected to the tank 39 via a connector 51 provided on the front shell 1 that partitions the constant pressure chamber 5 and the tank 39, and the other end is connected to the push rod 11 and the inside of the constant pressure chamber 5. It is spirally wound around the return spring 14 and then connected to a connector 52 provided on the valve body 7.
The connector 52 is connected to a radial passage 53 formed in the valve body 7 and a valve plunger 16.
The pressure chamber 35 is communicated with the pressure chamber 35 through an axial passage 54 formed in the shaft portion.

This pressure chamber 35 is isolated from the atmosphere by a seal member 55, which is supported by a nut 57 screwed into the cylindrical body 9 through a back-up spring 56. The valve plunger 16 is slidably passed through the seal member 55 while maintaining airtightness, and the input shaft 20
is interlocked with the valve plunger 16 inside the shaft portion thereof.

The rest of the structure is basically the same as the embodiment shown in FIG. 1, and the same or corresponding parts as in FIG. 1 are designated with the same reference numerals as in FIG. 1. It is clear that the same effects as those of the above-mentioned embodiments can be obtained in this embodiment as well.

Furthermore, FIG. 3 shows an embodiment in which a tank 39 is provided on the entire front surface of the front shell 1 in order to increase the volume of the tank 39 in FIG. The bolt 28 is passed through a tank 39 and projected forward, and the front surface of the tank 39 is used as a mounting surface for the master cylinder.

According to such a configuration, although the master cylinder is installed at a slightly forward position, it is possible to secure a tank 39 with a large capacity.

In addition, in each of the above embodiments, the tank 3
When increasing the volume of the tank 9, the tank 39 may be bulged forward in the axial direction at a position where it does not interfere with the reservoir 45 of the master cylinder 29, or the tank 39 may be extended continuously to the outer periphery of the front shell 1. You can also do this. Furthermore, although negative pressure is introduced into the constant pressure chamber 5 in the above embodiment, it is of course possible to introduce atmospheric air into the constant pressure chamber 5.

As described above, according to the present invention, it is possible to easily secure the mounting space for the tank, the piping connection work can be made easier, and the tank can be used as a reinforcing member for the shell. Therefore, the effect that the entire tank and brake booster can be made smaller and lighter than before can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing one embodiment of the present invention;
3 are sectional views showing other embodiments of the present invention. 1...Front shell, 2...Rear shell, 3
...Power piston, 4...Diaphragm, 5...
... constant pressure chamber, 6 ... variable pressure chamber, 7 ... valve body,
8... Valve mechanism, 11... Push rod, 20...
...Input shaft, 29...Master cylinder, 39...
Tank, 45...reservoir.

Claims (1)

[Scope of utility model registration request] A power piston is slidably disposed inside the shell, a diaphragm is disposed on the rear surface of the power piston and divides the inside of the shell into a constant pressure chamber in the front and a variable pressure chamber in the rear, and a valve mechanism that switches the fluid circuit accordingly and supplies positive pressure to the variable pressure chamber to advance the power piston; and an output shaft that receives the thrust of the power piston and operates a master cylinder provided in front of the shell. What is claimed is: 1. A brake booster comprising: a tank for accumulating positive pressure supplied to the variable pressure chamber on a side of the shell where a master cylinder is disposed;