JPH0315585B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a composite booster equipped with a negative pressure type and a hydraulic type booster mechanism, and is particularly suitable for operating a brake master cylinder of a vehicle.

Conventionally, a negative pressure booster using an engine intake manifold as a negative pressure source is known. In this device, the output is generated by the pressure difference acting on both the front and rear sides of the booster piston, so it has the advantage of less shock at the start of braking and good braking feeling. Due to these demands, there is a natural limit to its output characteristics, and there is a desire to improve its output.

The present invention has been proposed in view of the above, and allows a hydraulic booster mechanism to be easily incorporated into an existing negative pressure booster without sacrificing the advantages of the negative pressure booster. It is an object of the present invention to provide the above-mentioned compound booster which can improve its output and has a simple and compact structure.

In order to achieve this object, the present invention provides a booster shell, a booster piston that divides the interior of the booster shell into a first working chamber at the front and a second working chamber at the rear, and a a negative pressure booster mechanism comprising a negative pressure source communicating with the booster shell and an air pressure control valve that alternately controls communication between the second working chamber and the first working chamber or the atmosphere; a power cylinder integrally protruding in the direction; and a valve cylinder integrally provided on the outer periphery of a valve cylinder integrally protruding in the axial direction from the rear surface of the central portion of the booster piston and accommodating the air pressure control valve therein. and is slid into the power cylinder with the
The power cylinder is characterized by comprising: an output piston that defines an output hydraulic chamber in the rear portion of the power cylinder; and a hydraulic booster mechanism that includes a hydraulic power source connected to the output hydraulic chamber.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Reference numeral 1 denotes a booster shell constructed by abutting and assembling a pair of front and rear bowl-shaped bodies 1A and 1B. A first working chamber A at the front and a second working chamber at the rear are formed by a piston 2 and a diaphragm 3 having an inner peripheral bead fixed to its rear surface and an outer peripheral bead clamped between the bowl-shaped bodies 1A and 1B. It is divided into B and B. 1st
The working chamber A is always in communication with the intake manifold I of the internal combustion engine, which is a negative pressure source, via the pressure accumulation check valve 4.
The second working chamber B is alternately controlled to communicate with the first working chamber A or an atmosphere inlet 7 of a valve cylinder 6, which will be described later, via the air pressure control valve 5.

A coil type return spring 8 is compressed in the first working chamber A,
The return spring 8 always pushes the booster piston 2 in the backward direction, that is, toward the second working chamber B, and its backward limit is reached when the rib 3a formed protrudingly on the back surface of the piston diaphragm 3 comes into contact with the rear wall of the booster shell 1. Regulate by making it possible.

The booster piston 2 is integrally formed with a valve cylinder 6 projecting in the axial direction from the rear surface of its central portion, and the rear end thereof is opened as an air inlet 7.

The air pressure control valve 5 is configured in the valve cylinder 6 as follows. That is, an annular first valve seat 1 is provided on the front inner wall of the valve cylinder 6.
0 ₁ , and at the front of the valve cylinder 6 is a valve piston 12 connected to the input rod 11 and forming its front end.
are slid together to form an annular second valve seat 10 ₂ surrounded by the first valve seat 10 ₁ at the rear end of the valve piston 12 .

A base end 13a of a cylindrical valve element 13 with both ends open is clamped to the inner wall of the valve cylinder 6 via a valve element holding cylinder 14 fitted into the valve cylinder 6. This valve body 13 is made of an elastic material such as rubber, and its base end 1
A thin intermediate portion 13b extends radially inward from 3a, and a thick valve portion 1 is provided at the inner peripheral end of the intermediate portion 13b.
3c are arranged in series, and their valve portions 13c are opposed to the first and second valve seats 10 ₁ and 10 ₂ . Thus, the valve portion 13c can be moved back and forth by deforming the intermediate portion 13b.

An annular reinforcing plate 15 is embedded in the valve portion 13c, and a valve spring 16 acts on the annular reinforcing plate 15 to urge the valve portion 13c toward both valve seats 10 ₁ and 10 ₂ .

The outer part of the first valve seat ₁₀₁ is the booster piston 2
into the first working chamber A through a through hole 17, and an intermediate portion between the first and second valve seats 10 ₁ and 10 ₂ through another through hole 1
8 to the second working chamber B, and the second valve seat 10 ₂
The inner parts of the valve bodies 1 and 2 are in constant communication with the atmospheric air inlet 7 through the inside of the valve body 13.

In addition, on the front of the center of the booster piston 2,
A boss 21 having a stepped accommodation hole 20 of the reaction mechanism 19 is raised. The stepped hole 20 consists of a large diameter hole 22 that opens on the front surface of the boss 21, and a small diameter hole 23 connected to the back of the large diameter hole 22. The elastic piston 24 and the reaction piston 25 are sequentially slid into the hole 22, and the elastic piston 24 is inserted into the other two pistons 2.
It is interposed between 5 and 26. As a retaining member for preventing the reaction piston 25 at the forefront from coming off the large diameter hole 22, a circlip 27 having an expanding force is engaged with the inner peripheral wall of the large diameter hole 22 and is opposed to the front surface of the reaction piston 25. Thus, the three pistons 24, 25, and 26 constitute a reaction mechanism 19.

Furthermore, a valve piston 12 is provided in the small diameter hole 23.
A small shaft 12a protruding from the front end face of the pressure receiving piston 26 is inserted to face the rear end face of the pressure receiving piston 26.

On the other hand, a guide rod 28 projects from the front surface of the reaction piston 25, and the output rod 29, which penetrates the front wall of the booster shell 1 and comes into contact with the reaction piston 25, is supported by the guide rod 28 so as to be freely slidable and retractable. The guide rod 28 is manufactured separately from the reaction piston 25 in consideration of material yield, and is inserted into the center hole 25a of the reaction piston 25. At this time, a flange 28a protruding from the rear end of the guide rod 28 is sandwiched between the reaction piston 25 and the elastic piston 24 to prevent it from coming off.

A return spring 31 that springs the input rod 11 in the backward direction is compressed between the valve body holding cylinder 14 fixed to the valve cylinder 6 and the spring seat body 30 fixed to the input rod 11. A stopper 32 for regulating the limit is fixed to the small shaft 12a of the valve piston 12 in the small diameter hole 23. An air filter 33 is installed inside the rear opening of the valve body holding cylinder 14.

The negative pressure booster mechanism V is configured as described above.

The rear bowl-shaped body 1B is integrally formed with a power cylinder 34 that protrudes in the axial direction from the rear surface of its central part. End walls 35, 36
be slidably supported. On the outer peripheral surface of the valve cylinder 6,
The output piston 37 is integrally formed concentrically, and by sliding the output piston 37 into the power cylinder 34, the interior thereof is divided into an oil reservoir chamber C at the front and an output hydraulic chamber D at the rear.

A hydraulic power source 39 is connected to the output hydraulic chamber D via a hydraulic control valve 38.

The hydraulic power source 39 consists of a hydraulic pump 40, a pressure accumulator 41, an oil reservoir 42, etc.
The hydraulic power source is used to save space and reduce costs.

The hydraulic control valve 38 has a valve box 44 and a pressure difference detection box 45 separated by a partition wall 43.
4 is divided into an oil supply chamber E on the side of the pressure difference detection box 45 and an oil drain chamber F on the opposite side by a valve seat 48 slidably engaged therewith. A pressure spring 49 is compressed in the oil drain chamber F, and the elastic force of the pressure spring 49 causes the valve seat 4 to be compressed.
Both chambers E and F are secured by bringing the outer peripheral edge of 8 into contact with the stepped portion 50 between both chambers E and F.

A valve body 51 is slidably supported through the partition wall 43, and its tip is opposed to the valve hole 5 of the valve seat 48.
In addition, the base end is inserted into the air pressure difference detection box 45 into the oil supply chamber E.
The first working chamber a on the side and the second working chamber b on the opposite side
It is fixed to a diaphragm 53 that divides the 1st
A return spring 54 is contracted in the working chamber a, and the elastic force of the return spring 54 brings the base end surface of the valve body 51 into contact with the inner surface of the outer wall of the second working chamber b, thereby opening the valve hole 52. ing.

In the hydraulic control valve 38, the inlet side of the oil supply chamber E is connected to the pressure accumulator 41 via an oil passage 55, and the outlet side is connected to the output hydraulic chamber D of the power cylinder 34 via an oil passage 56, respectively. On the other hand, set the oil drain chamber F to 2.
The oil sump 4 of the hydraulic source 39 is connected to the main oil passages 57 and 58.
2 and the oil reservoir chamber C of the power cylinder 34, respectively.

In the pressure difference detection box 45, the first working chamber a is connected to the first working chamber A of the booster shell 1 through the connecting path 59, and the second working chamber b is connected to the second working chamber A of the booster shell 1 through the connecting path 60. Each is connected to room B.

The hydraulic booster mechanism H is configured as described above.

In the passenger compartment, the input rod 11 of the negative pressure booster mechanism V
A brake pedal 63, which is pivoted 62 on a fixed bracket 61, is connected to the rear end via a connecting fitting 64. 65 is a return spring that biases the brake pedal 63 rearward.

Cylinder body 66 of brake master cylinder M
The rear end is fitted into a recess 67 formed in the front wall of the booster shell 1, and the output rod 29 of the negative pressure booster mechanism V is inserted into the rear end of the actuating piston 68 in the cylinder body 66. Penetrate and face each other.

Next, to explain the operation of this embodiment, the drawing shows the non-operating state, and the input rod 11 and the booster piston 2 are held at a predetermined retracted position by the elastic force of the return springs 8 and 31, respectively, and the valve The piston 12 uses the elastic force of the return spring 31 to seat the second valve seat 10 ₂ on the front surface of the valve portion 13c, and
It is spaced apart from the first valve seat 10 ₁ to form a gap g therebetween. 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 portion 13c communicates with the second working chamber B through the through hole 17, the gap g, and the through hole 18. Since the valve seat ₁₀₂ is closed, 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 controlled by the return spring 8. It is placed below.

In addition, with the balance of air pressure in the first and second working chambers A and B, the first and second working chambers a and b of the hydraulic control valve 38
The internal air pressure is also balanced through the connecting paths 59 and 60, and the elastic force of the return spring 54 causes the base end surface of the valve body 51 to come into contact with the inner surface of the outer wall of the second working chamber b, opening the valve hole 52. . As a result, the oil supply chamber E communicates with the oil drain chamber F through the valve hole 52, so that no pressure oil enters the output hydraulic chamber D of the power cylinder 34.

Now, when the brake pedal 63 is depressed to brake the vehicle and 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, moves forward following the valve piston 12. Immediately seats the first valve seat 10 ₁ to cut off communication between the working chambers A and B, and at the same time the second valve seat 10 ₂ seats the valve part 1.
3c, the second working chamber B is communicated with the atmosphere inlet 7 through 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 this chamber B becomes higher than that in the first working chamber A, and as a result of the forward pressing force caused by the pressure difference between the two chambers A and B. Booster piston 2 moves forward against return spring 8.

A portion of the atmosphere introduced into the second working chamber B of the booster shell 1 is supplied to the hydraulic control valve 38 via the connection path 60.
is introduced into the second working chamber b, which has a higher pressure than the first working chamber a, and the pressure difference created between the two chambers a and b causes the valve body 51 to move forward against the return spring 54, Since the valve hole 52 is closed, pressure oil from the pressure accumulator 41 enters the output hydraulic chamber D of the power cylinder 34 via the oil passage 55, the oil supply chamber E, and the oil passage 56, and enters the output piston 37, that is, the booster piston 2. A forward pressing force is applied by hydraulic pressure.

As a result, the booster piston 2 moves forward in response to the combined pressing force from the negative pressure booster mechanism V and the hydraulic booster mechanism H, and moves the output rod 29 forward via the elastic piston 24 and the reaction piston 25, so that the brake master cylinder M The operating piston 68 is driven forward and strong braking is applied to the vehicle.

On the other hand, due to its advancement, the small shaft 12a of the valve piston 12 passes through the pressure receiving piston 26 to the elastic piston 2.
4, the reaction piston 2 is released from the output rod 29.
5 causes a part of the elastic piston 24 to bulge and deform toward the small-diameter hole 23 side, and as a result, a part of the reaction force is fed back to the brake pedal 63 side via the pressure receiving piston 26 and the valve piston 12. Thus, the driver can sense the output of the output rod 29, that is, the braking force.

Next, when the depression force of the brake pedal 63 is released, the input rod 11 is moved backward due to the reaction force exerted on the valve piston 12 and the elastic force of the return spring 31, and this causes the second valve seat 10 ₂ to move toward the valve position. At the same time, the valve portion 13c is seated on the first valve seat 10.
₁ , and a gap g is again formed between them, so that the air pressures in both working chambers A and B quickly become equal to each other through the gap g. As the air pressures in both working chambers A and B are balanced, the air pressures in both working chambers a and b of the hydraulic control valve 38 are also balanced, so the elastic force of the return spring 54 causes the valve body 51 to be separated from the valve seat 48. Open the valve hole 52.

Then, the booster piston 1 is moved back by the elastic force of the return spring 8 due to the balance of the air pressure in the first and second working chambers A and B of the booster shell 1 and the opening of the valve hole 52 of the hydraulic control valve 38 .

As described above, according to the present invention, a booster shell, a booster piston that partitions the interior of the booster shell into a first working chamber at the front and a second working chamber at the rear, and a booster piston that is always in communication with the first working chamber. a negative pressure booster mechanism comprising a negative pressure source and an air pressure control valve that alternately controls communication between the second working chamber and the first working chamber or the atmosphere; a power cylinder integrally protruding from the center of the booster piston; A hydraulic booster mechanism comprising: an output piston that slides into a power cylinder and defines an output hydraulic chamber at the rear of the power cylinder; and a hydraulic power source connected to the output hydraulic chamber; The output of the negative pressure booster can be improved without sacrificing the advantages of the booster. Furthermore, in the existing negative pressure booster mechanism, the output of the hydraulic booster mechanism can be improved by simply making a slight design change to the valve cylinder and its sliding guide tube that protrude from the rear surfaces of the booster piston and booster shell, respectively. Since it can be used as both the piston and the power cylinder, it is possible to incorporate the hydraulic booster into the negative pressure booster without increasing the number of parts, resulting in a simple structure, cost reduction, and maintenance. It can greatly contribute to improving work efficiency. In addition, even in conventional negative pressure boosting mechanisms, the output piston of the hydraulic boosting mechanism is integrated into the valve cylinder, which protrudes relatively long from the rear surface of the booster piston, resulting in an increase in size due to the incorporation of the hydraulic boosting mechanism. This is advantageous in reducing the size of the compound booster in the axial direction of the booster piston.

[Brief explanation of the drawing]

The drawing is a longitudinal side view showing an embodiment of the present invention. A...First working chamber, B...Second working chamber, D...Output hydraulic chamber, H...Hydraulic booster, V...Negative pressure booster, 1...Booster shell, 2...Booster piston, 5...Air pressure control Valve, 34...Power cylinder, 3
7... Output piston, 39... Hydraulic power source.

Claims (1)

[Scope of Claims] 1. A booster shell 1, a booster piston 2 that divides the interior of the booster shell 1 into a first working chamber A at the front and a second working chamber B at the rear, and Negative pressure source I in constant communication and the second working chamber B
a negative pressure booster mechanism V, which includes a pressure control valve 5 that alternately controls communication between the booster shell 1 and the first working chamber A or the atmosphere; power cylinder 34
The valve cylinder 6 is integrally provided on the outer periphery of a valve cylinder 6 that integrally projects from the rear surface of the central portion of the booster piston 2 in the axial direction and accommodates the air pressure control valve 5 therein, and is slidably fitted into the power cylinder 34. Being done,
A hydraulic booster mechanism H comprising: an output piston 37 that partitions an output hydraulic chamber D in the rear part of the power cylinder 34, and a hydraulic power source 39 connected to the output hydraulic chamber D; . 2. A compound booster according to claim 1, wherein the negative pressure source is an intake manifold I of an engine, and the hydraulic pressure source is a power steering hydraulic pressure source 39.