JPH046575B2 - - Google Patents

Description

Detailed Description of the Invention A. Purpose 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 which is constantly in communication with a negative pressure source and a second working chamber whose communication with the first working chamber or the atmosphere is switched and controlled via a control valve, and the booster piston is connected to the booster piston. The present invention relates to an improvement in which the control valve responsive to the movement of the input rod is provided between the control valve and an input rod connected to the input rod so as to be movable forward and backward, 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 composed of a cylinder body fixed to the front surface of the booster shell, and a piston that is slid into the cylinder hole of the cylinder body and connected to the booster piston (for example, see Utility Model Publication No. 59-14300). reference).

(3) Problems to be solved by the invention In the conventional negative pressure booster with a master cylinder,
Since the cylinder body of the master cylinder protrudes for a long time from the front surface of the booster shell, the axial length of the entire device becomes very long, and there is a problem in that a large installation space is required when mounting it on the vehicle body.

Further, in the conventional negative pressure booster with a master cylinder, most of the space adjacent to the rear of the booster shell rear wall is a dead space.

The present invention has been proposed 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.

B. Structure of the Invention (1) Means for Solving the Problems In order to achieve the above object, according to the present invention, a booster piston that is capable of reciprocating back and forth within the booster shell is used to provide a booster piston on the front side that is always in communication with a negative pressure source. The booster piston is divided into a first working chamber and a rear second working chamber whose communication with the first working chamber or the atmosphere is switched and controlled via a control valve, and the input rod is connected to the booster piston so as to be able to move forward and backward. In the negative pressure booster with a master cylinder, the master cylinder is provided with the control valve that responds to input movement, and the master cylinder is actuated by the booster piston, wherein the master cylinder is fixed to the booster piston. It is composed of a cylinder body whose front part protrudes into the first working chamber, and a piston that is slidably fitted into a cylinder hole of the cylinder body and fixed to the booster shell, and the rear part of the cylinder body is , which passes through the rear wall of the booster shell airtightly and slidably and extends to the rear of the rear wall, and an output port that communicates with the output hydraulic chamber in the cylinder body is bored in the extending portion. will be established.

(2) Function Since most of the cylinder body of the master cylinder is accommodated in the booster shell, spanning the first and second working chambers, the amount of protrusion of the cylinder body outside the booster shell can be reduced. , the axial length of the device can be significantly shortened.

Moreover, the output port of the master cylinder is opened to the space adjacent to the rear of the rear wall of the booster shell,
Since a portion of the hydraulic piping can now be routed through the same space, the space, which has traditionally been considered a dead space, can be used effectively.

(3) Embodiment An embodiment of the present invention will be described below with reference to the drawings. Booster shell 1 of negative pressure booster S
is constructed by butt-joining a pair of front and rear bowl-shaped bodies 1A, 1B, and the front bowl-shaped body 1A 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 1A and 1B. , is divided into a first working chamber A at the front 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 now 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 the center thereof, and the valve cylinder 8 is airtightly mounted on a flat bearing 9 fixed to the rear extension cylinder 1a of the booster shell 1. 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 f for filtering the introduced air is provided there.

A control valve 5 is provided in the well 8 as follows.

That is, the front end wall of the valve cylinder 8 has a cylinder hole 20;
An annular first valve seat 1 surrounding this cylinder hole 20
0 ₁ is formed, and a valve piston 12 connected to the front end of the input rod 11 operated by the brake pedal P is slid in the cylinder hole 20, and the first valve seat 10 ₁ is attached to the rear end of the valve piston 12. An annular second valve seat 10 ₂ is formed surrounded by the second valve seat 10 2 .

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 valve portion 13c.
are arranged facing the first and second valve seats 10 ₁ and 10 ₂ . Thus, the valve portion 13c is connected to the intermediate portion 13b.
It can be displaced back and forth by deforming.

An annular reinforcing plate 15 is embedded in the valve portion 13c, and the valve portion 13c is connected to both valve seats 10 ₁ and 10 _{2 .}
The force of the valve spring 16 is applied to bias it towards.

The outer part of the first valve seat ₁₀₁ is connected to the first working chamber A through the through hole 17 of the booster piston 2, and to the first valve seat 101.
And the middle part of the second valve seat 10 ₁ , 10 ₂ is another through hole 1
8 to the second working chamber B, and further to the second valve seat 10
The inner part of ₂ is connected to the atmosphere inlet 6 through the inside of the valve body 13.
are in constant communication with each other.

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,
The input rod 11 is urged in the backward direction by the spring 46, 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 of the cylinder hole 20, and a pressure receiving piston 22 whose front surface faces the reaction hydraulic pressure chamber 21 is integrated with the front surface of the valve piston 12. It will be installed protrudingly.

Furthermore, first and second master cylinders M ₁ and M ₂ are attached to the booster piston 2 with the valve cylinder 8 in between. These master cylinders M ₁ and M ₂ each have a cylinder body 2 that is integrally formed with the booster piston 2 and extends parallel to the axis of the piston 2.
3 and the cylinder hole 23a of this cylinder body 23
The front part of the cylinder body 23 protrudes into the first working chamber A,
On the other hand, the rear portion of the booster shell 1 passes through the rear bowl-shaped body 1B, which is the rear wall of the booster shell 1, in an airtight and slidable manner via a plain bearing 25, and extends to the rear of the rear wall. The output ports 23p of the master cylinders M ₁ and M ₂ are bored.

The piston 24 defines a braking hydraulic chamber 26 as an output hydraulic chamber communicating with the output port 23p at the rear of the cylinder hole 23a, and a replenishing oil chamber 27 at the front thereof. This piston 24 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 a spring 28 that maintains this supported state is compressed in the brake hydraulic chamber 26. Ru. The piston 24 has a valve hole 29 that communicates between the braking oil pressure chamber 26 and the replenishment oil chamber 27.
is bored in the center, and a valve handle 30a of the valve body 30 opens and closes the opening of the valve hole 29 to the brake hydraulic chamber 26.
is arranged so as to loosely pass through the valve hole 29,
The valve body 30 is urged 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's becoming like that.

The replenishment oil chambers 27, 27 of the first and second master cylinders M ₁ , M ₂ are independent first and second oil sump chambers 3 of an oil sump 33 installed outside the booster shell 1.
3 ₁ and 33 ₂ via conduits 34 ₁ and 34 ₂ , respectively, and are filled with hydraulic oil supplied from each oil reservoir chamber 33 ₁ and 33 ₂ .

The braking hydraulic chamber 26 of the first master cylinder _M1 is
The brake hydraulic chamber 26 of the second master cylinder M2 is connected to the left front wheel brake Bfl and the right rear wheel brake Brr of the automobile via a first hydraulic conduit ₃₅₁ connected to an output port _23p communicating with the chamber 26. ,
It is connected to the right front wheel brake Bfr and the left rear wheel brake Brl of the automobile via a second hydraulic conduit 35 ₂ connected to the output port 23p communicating with the chamber 26 .

A reaction force generating cylinder 36 is connected to the first and second hydraulic conduits 35 ₁ and 35 ₂ . The reaction force generating cylinder 36 is composed of a cylinder body 37 and a pair of pistons 38 _{1 and 38 2} that are slidably fitted in the cylinder hole 37a of the cylinder body 37.
Input chambers 39 ₁ , 3 between both end walls of the cylinder body 37
9 ₂ and an output chamber 40 between the pistons 38 ₁ and 38 ₂ . And one input room 39
₁ has a first hydraulic conduit 35 ₁ and the other input chamber 3
A second hydraulic conduit 35 ₂ is connected to each of 9 ₂ ,
Further, the reaction hydraulic pressure chamber 21 is connected to the output chamber 40 via a conduit 41. Further, a common return spring 42 is provided in the output chamber 40 and urges both the pistons 38 ₁ and 38 ₂ 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 ₂ on the front surface of the valve portion 13c, and
The valve portion 13c is spaced apart from the valve seat ₁₀₁ to form a gap g therebetween. Therefore,
A through hole 17 is provided in the first working chamber A that constantly stores negative pressure.
It communicates with the second working chamber B through the gap g and the through hole 18, and the front opening of the valve portion 13c is connected to the second valve seat 10.
₂ , the negative pressure in the first working chamber A is transmitted to the second working chamber B, the air pressure in both working chambers A and B is balanced, and the booster piston 2 is closed by the return spring 7.
be under the control of

Now, when the brake pedal P is depressed to brake the automobile and the input rod 11 and piston 12 are moved forward, the valve portion 1 is urged forward by the valve spring 16.
3c moves forward following the valve piston 12 and immediately seats on the first valve seat ₁₀₁ , cutting off the communication between both working chambers A and B, and at the same time, the second valve seat ₁₀₂ moves forward and seats on the first valve seat 101.
The second working chamber B is separated from the through hole 18 and the valve body 13.
It communicates with the atmosphere inlet 6 through the inside. Therefore, the atmosphere is quickly introduced into the second working chamber B,
The pressure in the chamber B is higher than that in the first working chamber A, and the pressure difference between the two chambers A and B causes the booster piston 2 to move forward against the force of the return spring 7. This forward movement of the booster piston 2 is caused by the movement of both master cylinders M ₁ ,
Since the cylinder bodies 23, 23 of _M2 move forward, the valve hole 29 is closed by the valve body 30, 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 passes through the first hydraulic conduit ₃₅₁ to brake the left front wheel.
Bfl and the right rear wheel brake Brr to operate them, and the brake hydraulic pressure chamber ₂ of the second master cylinder M2
The hydraulic pressure output from 6 passes through the second hydraulic conduit ₃₅₂ to the right rear wheel brake Bfr and the left rear wheel brake Brl.
to operate these.

During this time, in the reaction force generating cylinder ₃₆ , the first and _second hydraulic conduits 35 ₁ ,
Since the hydraulic pressures of 35 ₂ act on each of them, the pistons 38 ₁ and 38 ₂ act on the return spring 42 in response to these hydraulic pressures.
They are mutually displaced inwardly against the force, generating hydraulic pressure in the output chamber 40, and this generated hydraulic pressure is transmitted to the reaction hydraulic pressure chamber 21 through the conduit 41 to apply a braking reaction force to the pressure receiving piston 22, thereby The driver can sense the output of the booster piston 2, that is, the magnitude of the braking force.

By the way, the cylinder body 23 of each master cylinder M ₁ , M ₂ is integrally formed with the booster piston 2, and the piston 24 is fixed to the booster shell 1, so that most of the master cylinders M ₁ , M ₂ are attached to the booster shell 2. 1, and the cylinder body 23
The amount of protrusion of the booster shell 1 to the rear is extremely small.

C. Effects of the Invention As described above, according to the present invention, the master cylinder attached to the negative pressure booster includes a cylinder body that is fixedly attached to the booster piston and whose front part protrudes into the first working chamber; and a piston that is slidably fitted into the cylinder hole of the cylinder and fixed to the booster shell, and the rear part of the cylinder body airtightly and slidably penetrates the rear wall of the booster shell. It extends to the rear of the wall, and an output port that communicates with the output hydraulic chamber in the cylinder body is bored in the extension, so that most of the cylinder body of the master cylinder is connected to the first cylinder in the booster shell. , the cylinder body can be accommodated across the second working chamber, and the amount of protrusion of the cylinder body to the outside of the booster shell can be reduced, thereby achieving compactness of the device, in particular, a significant reduction in the axial length. I can do it. Furthermore, by opening the output port of the master cylinder into the space adjacent to the rear of the rear wall of the booster shell, it is now possible to route part of the hydraulic piping into the same space, thereby freeing up the space that was previously considered a dead space. It can be used effectively and can be installed in front of the booster shell without any support even in structures where there is limited space.

[Brief explanation of drawings]

The drawing shows one embodiment of the present invention, and is a longitudinal sectional view of a negative pressure booster with a master cylinder connected to a brake hydraulic circuit of an automobile. A, B...first and second working chambers, _M1 , _M2 ...master cylinder, S...booster, V...negative pressure source,
DESCRIPTION OF SYMBOLS 1... Booster shell, 1B... Rear bowl-shaped body as rear wall, 2... Booster piston, 5... Control valve, 11... Input rod, 23... Cylinder body, 2
3a...Cylinder hole, 23p...Output port, 2
4... Piston, 26... Braking oil pressure chamber as an output oil pressure chamber, 27... Replenishment oil chamber.

Claims (1)

[Claims] 1 The booster piston 2, which can reciprocate back and forth within the booster shell 1, switches between the first working chamber A on the front side, which is always in communication with the negative pressure source V, and the first working chamber A or the atmosphere via the control valve 5. The control valve 5 is divided into a rear second working chamber B to be controlled, and the control valve 5 is provided between the booster piston 2 and an input rod 11 connected to the booster piston 2 so as to be able to move forward and backward, and responds to the movement of the input 11. In the negative pressure booster with a master cylinder in which the booster piston 2 operates the master cylinders M ₁ and M ₂ , the master cylinders M ₁ and M ₂ are fixed to the booster piston 2 and have a front portion. It is composed of a cylinder body 23 that protrudes into the first working chamber A, and a piston 24 that is slidably fitted into the cylinder hole 23a of the cylinder body 23 and fixed to the booster shell 1. The rear part of the main body 23 passes through the rear wall 1B of the booster shell 1 in an airtight and slidable manner and extends to the rear of the rear wall 1B. A negative pressure booster with a master cylinder, characterized in that an output port 23p communicating with a hydraulic chamber 26 is bored.