JPS62116348A - Negative-pressure type booster equipped with master cylinder - Google Patents

Abstract

PURPOSE:To make the apparatus compact, particularly reduce the length in the axial direction, by constituting a master cylinder from a cylinder body fixed onto a booster piston and a piston fixed onto a booster shell. CONSTITUTION:The captioned apparatus is equipped with a booster shell 1 divided into the first working chamber A which communicates to a negative pressure source V and the second working chamber B which communicates to the atmosphere or the first working chamber A through a control valve 5, by a booster piston 2 which moves freely in reciprocation in the longitudinal direction. The control valve 5 is controlled through an input lever 11 according to the operation of a brake pedal P. In this case, two master cylinders M1 and M2 are installed onto the booster piston 2, keeping a valve cylinder 8 for accommodating the control valve 5 interposed. Each master cylinder M1, M2 is constituted of a cylinder body 23 formed integrally with the booster piston 2 and a piston 24 fitted in slidable ways into the cylinder hole 23a, and said piston 24 is supported at the top edge of a bolt 4 fixed onto a chassis F.

Description

Detailed Description of the Invention A0 Object of the Invention (1) Industrial Application Field The present invention relates to a negative pressure booster with a master cylinder for operating hydraulic brakes of automobiles, etc. The booster piston is divided into a first working chamber that is constantly connected to a negative pressure source and a second working chamber that is controlled to communicate with the first working chamber or the atmosphere via a control valve. The present invention relates to an improvement in which the control valve that responds to the movement of the input rod is provided between the input rod and the input rod that is movably connected thereto, and the master cylinder is actuated by the booster piston.

(2) Conventional technology Conventionally, in such a booster with a master cylinder, the master cylinder is connected to a cylinder body fixed to the front surface of a booster shell, and a cylinder hole in the cylinder body, and connected to a booster piston. (For example, see Utility Model Publication No. 59-14300)
.

(3) Problems to be solved by the invention In conventional negative pressure boosters with master cylinders, the cylinder body of the master cylinder protrudes long from the front of the booster shell, so the axial length of the entire device is extremely long. Therefore, there is a problem in that a large installation space is required when installing it on the vehicle body.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a compact negative pressure booster with a master cylinder having a short axial length.

B9 Structure of the Invention (Means for Solving Problems 1 and 1) In order to achieve the above object, the present invention provides the master cylinder with a cylinder body fixed to a booster piston, and a cylinder hole of the cylinder body. and a piston that is slidably engaged with the booster shell and fixed to the booster shell.

(2) Effects According to the above configuration, most of the master cylinder is accommodated within the booster shell, and the amount of protrusion of the cylinder body to the outside of the booster shell can be kept small.

(3) Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings.The booster shell l of the negative pressure booster S is constructed by abuttingly coupling a pair of bowl-shaped bodies IA and IB at the front and the front. The bowl-shaped body IA is fixed to the vehicle body F of the automobile with a pair of bolts 4, 4. The interior of the booster shell 1 consists of a booster piston 2 that can reciprocate back and forth, and a diaphragm 3 that has an inner beat fixed to an annular groove 2a on the rear surface and an outer beat sandwiched between the bowl-shaped bodies IA and IB. , front first working chamber A
and a second working chamber B at the rear.

The first working chamber A is always in communication with a negative pressure source V, for example, the intake manifold of an internal combustion engine, and the second working chamber B is alternately connected to the first working chamber A or an atmospheric air inlet 6, which will be described later, via a control valve 5. Communication is switched.

The booster piston 2 is always urged in the backward direction, that is, toward the second working chamber B, by a return spring 7 contracted in the first working chamber A, and its backward limit is set by a protrusion formed on the rear surface of the diaphragm 3. 3a comes into contact with the rear wall of the booster shell 1, thereby being regulated.

The booster piston 2 is integrally formed with a valve cylinder 8 that protrudes in the axial direction from the rear surface of its central portion. Moreover, it is slidably supported. The rear end of the valve cylinder 8 is opened as an air inlet 6, and a highly flexible filter r for filtering the introduced air is provided there.

A control valve 5 is provided within the valve cylinder 8 as follows.

That is, a cylinder hole 20 and an annular first valve seat 101 surrounding the cylinder hole 20 are formed in the front end wall of the valve cylinder 8. A valve piston 12 connected to the front end is slidably connected to the rear end of the valve piston 12, and the first valve seat 10 is connected to the rear end of the valve piston 12.
．． An annular second valve seat 10□ is formed surrounded by the second valve seat 10□.

A base end 13 a of a cylindrical valve body 13 with both ends open is clamped on the inner wall of the valve cylinder 8 via a valve body holding cylinder 14 fitted into the valve cylinder 8 . This valve body 13 is molded from an elastic material such as rubber, and has a thin intermediate portion 13b extending radially inward from its base end 13a, and a thick valve at the inner peripheral end of the intermediate portion 13b. The valve portion 13c is connected to the first and second valve seats 10. ．． 10g. Thus, the valve portion 13C can be displaced back and forth by deforming the intermediate portion 13b.

An annular reinforcing plate 15 is embedded in the valve portion 13C, and this includes the valve portion 13C and both valve seats 10. ．． The force of valve spring 16 is applied to bias towards valve spring 102 .

1st valve seat 10. is connected to the first working chamber A through the through hole 17 of the booster piston 2, and to the first and second valve seats 1.
0. ．． The middle portion of the valve seat 10 □ is in constant communication with the second working chamber B through another through hole 18 , and the inner portion of the second valve seat 10 □ is in constant communication with the atmosphere inlet 6 through the inside of the valve body 13 .

A return spring 46 is compressed between the valve holding cylinder 14 and a spring seat body 45 that is locked to the input rod 11, and this spring 46 urges the input rod 11 in the backward direction, and the valve holding cylinder 14 is fixed to the valve cylinder 8.

Further, the booster piston 2 is provided with a reaction hydraulic pressure chamber 21 adjacent to the front side of the cylinder hole 20, and a pressure receiving piston 22 whose front side faces the reaction force hydraulic chamber 21 is located at the front side of the valve piston 12. It is installed integrally with the

Furthermore, first and second master cylinders Ml and Mz are attached to the booster piston 2 with the valve cylinder 8 in between. These master cylinders M+ and Mt each include a cylinder body 23 that is integrally formed with the booster piston 2 and extends parallel to the axis of the piston 2, and a cylinder body 23 that is integrally formed with the booster piston 2 and extends parallel to the axis of the piston 2.
The cylinder body 23 is airtightly and slidably supported on the rear wall of the booster shell 1 via a flat bearing 25. The piston 24 defines a braking oil pressure chamber 26 at the front of the cylinder hole 23a and a rear supply oil chamber 27. This piston 24 is
A spring 28 is compressed in the braking hydraulic chamber 26 and is supported by the rear end of a fixed rod 4a that is integrally connected to the bolt 4 and projects into the first working chamber A, and maintains this supported state. A valve hole 29 is bored in the center of the piston 24 to communicate between the brake oil pressure chamber 26 and the replenishment oil chamber 27, and a valve body 30 opens and closes the opening of the valve hole 29 to the brake oil pressure chamber 26. Rod 30a
is arranged so as to loosely pass through the valve hole 29, and the valve body 3
0 is biased in the valve closing direction by the force of the valve spring 31. A valve opening rod 32 that crosses the replenishment oil chamber 27 is fixed to the cylinder body 23, and this valve opening rod 32 pushes the valve rod 30a at the retraction limit of the cylinder body 23 to give a valve opening action to the valve body 30. It looks like this.

Supply oil chamber 2 for the first and second master cylinders M+ and Mz
7.27 is connected to the independent first and second oil sump chambers 3L and 33□ of the oil sump 33 installed outside the booster shell l through conduits 341 and 341, respectively, and each oil sump chamber 3
3+, filled with hydraulic oil supplied from 33g.

The brake hydraulic chamber 26 of the first master cylinder M1 is connected to the left front wheel brake Bre and the right rear wheel brake 1lrr of the automobile via a first hydraulic conduit 351, and the brake hydraulic chamber 26 of the second master cylinder M2 is connected to the right front wheel brake Bfr and left rear wheel brake Brl of the automobile via a second hydraulic conduit 35□.

A reaction force generating cylinder 36 is connected to the first and second hydraulic conduits 35+ and 35□. The reaction force generating cylinder 36 has a cylinder body 37 and a cylinder hole 3 of this cylinder body 37.
A pair of pistons 38.7a are slidably connected to each other. ．． 3B□, these pistons 3B, 38□ define input chambers 39+, 39g between both end walls of the cylinder body 37 in the cylinder hole 37a, and both pistons 38. ,3
An output chamber 40 is defined between 8□. And one entrance room 3
9. A first hydraulic conduit 351 is connected to the input chamber 39 of the other input chamber.
A second hydraulic conduit 35□ is connected to each of □, and the reaction force hydraulic chamber 21 is further connected to the output chamber 40 via a conduit 41. Also, both pistons 38. ,3
One return spring 42 is contracted to urge B□ in the direction of separation.

Next, to explain the operation of this embodiment, the figure shows a non-operating state, and the input rod 11 and the booster piston 2 are held at a predetermined retreated position by the elastic force of the return springs 7 and 46, respectively. The valve piston 12 uses the elastic force of the return spring 46 to seat the second valve seat 10 on the front surface of the valve portion 13c, and also separates the valve portion 13c from the first valve seat 101 to create a gap g between them. is forming. Therefore, the first working chamber A, which constantly stores negative pressure, communicates with the second working chamber B through the through hole 17, the gap g, and the through hole 18, and the front opening of the valve part 13c is connected to the second valve seat. 10, the negative pressure in the first working chamber A is transmitted to the second working chamber B, and the air pressure in both working chambers A and B is balanced, and the booster piston 2
is under the control of a return spring 7.

Now, to brake the car, step on the brake pedal P,
When the input rod 11 and the valve piston 12 are moved forward, the valve portion 13C, which is urged forward by the valve spring 16, is moved forward by the valve piston 1.
2 and immediately move forward following the first valve seat 10. seated in
The communication between both working chambers A and B is cut off, and at the same time the second valve seat 10
2 is separated from the valve portion 13C and communicates the second working chamber B with the atmosphere inlet 6 via the through hole 18 and the inside of the valve body 13. Therefore, the atmosphere is quickly introduced into the second working chamber B, and the pressure in the second working chamber B becomes higher than that in the first working chamber A.

The booster piston 2 moves forward against the force of the return spring 7 due to the pressure difference generated between the two. This forward movement of the booster piston 2 causes the cylinder bodies 23, 23 of both master cylinders M, , M2 to move forward, so that the valve body 3
0, the valve hole 29 is closed, and hydraulic pressure is generated in the braking hydraulic chamber 26 according to the amount of advance of the cylinder body 23. The hydraulic pressure output from the brake hydraulic chamber 26 of the first master cylinder M1 is transferred to the first hydraulic conduit 35. Through the left front wheel brake B
fA and the right rear wheel brake Brr to operate them, and the second master cylinder M! The hydraulic pressure output from the brake hydraulic chamber 26 of the second hydraulic pressure conduit 35. is transmitted to the front right wheel brake Bfr and the rear left wheel brake Brl to operate them.

During this time, in the reaction force generating cylinder 36, the inner chamber 391.
391, first and second hydraulic conduits 35°, 35. , the pistons 381 and 38□ are mutually displaced inwardly against the force of the return spring 42 in response to these oil pressures, generating oil pressure in the output chamber 40, and this generated oil pressure is transferred to the conduit 41. A braking reaction force is transmitted to the reaction force hydraulic chamber 21 through the pressure receiving piston 22, thereby allowing the operator to sense the output of the booster piston 2, that is, the magnitude of the braking force.

By the way, since the cylinder body 23 of each master cylinder M+, Mz is integrally formed with the booster piston 2, and the piston 24 is fixed to the booster shell 1, most of both master cylinders M+, Mt are accommodated in the booster shell l. Therefore, the amount of protrusion of the cylinder body 23 toward the rear of the booster shell 1 is extremely small.

C1 Effects of the Invention As described above, according to the present invention, in the negative pressure booster with a master cylinder, the master cylinder is slidably fitted into the cylinder body fixed to the booster piston and the cylinder hole of the cylinder body. Since the master cylinder is constructed with a piston fixed to the booster shell, most of the master cylinder is housed within the booster shell, and therefore the amount of protrusion of the cylinder body outside the booster shell is reduced, making the device more compact, especially in the axial direction. The length can be significantly shortened.

[Brief explanation of drawings]

The drawing shows one embodiment of the present invention, and is a longitudinal sectional view of a negative booster with a master cylinder connected to a brake hydraulic circuit of an automobile. A, B... 1st. Second working chamber, M... Master cylinder, S... Booster, ■... Negative pressure source 1...
・Booster shell, 2...Booster piston, 5...
・Control valve, 11... Input rod, 23... Cylinder body, 2.3a... Cylinder hole, 24... Piston, 2
6...Brake oil pressure chamber, 27...Replenishment oil chamber

Claims (1)

[Claims] A booster piston that can reciprocate back and forth within the booster shell has a first working chamber that is constantly in communication with a negative pressure source, and a second working chamber that is controlled to communicate with the first working chamber or the atmosphere via a control valve. The control valve that responds to the movement of the input rod is provided between the booster piston and an input rod that is movably connected to the booster piston, and the booster piston operates the master cylinder. The pressure type booster is characterized in that the master cylinder is composed of a cylinder body fixed to a booster piston, and a piston slidably engaged with a cylinder hole of the cylinder body and fixed to the booster shell. Negative pressure booster with master cylinder.