JPS6255253A - Hydraulic booster with brake pressure retaining function - Google Patents

Abstract

PURPOSE:To make it possible to retain the brake pressure commonly to each wheel of a four-wheeled vehicle with a single solenoid valve by connecting a control pressure chamber with a hold oil chamber via a solenoid valve device opened by brake pressure retention command. CONSTITUTION:At the bottom of an inner cylinder 36a of a boost piston 33 is formed a hold oil chamber D2 faced by a stepped shoulder section of the boost piston 33. And an oil chamber D is connected via a radial flow passage 36b of a stopper ring 36, a port 42 and further a solenoid valve device 44 to a control pressure chamber C. The solenoid valve device 44 consists of a normally closed type solenoid valve 45 and a return valve 46 which allows only the flow of pressure oil of both the hold oil chamber D and the control pressure chamber C, with the both valves connected in parallel so that the pressure oil in the control pressure chamber C can be introduced into the hold oil chamber D only when the solenoid valve 45 opens its passage.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a hydrobooster for a vehicle brake system.
More specifically, the present invention relates to a hydraulic booster equipped with a brake hydraulic pressure holding device that maintains the brake hydraulic pressure of a vehicle that has stopped due to braking until the next time the vehicle starts moving.

[Background of the invention]

In the past, various hydraulic pressure boosters (hydro boosters) have been provided as brake force boosters for vehicle braking systems. A brake pressure holding device that maintains the pressure until the vehicle starts has also been provided.

By the way, each of these devices serves a completely different purpose, and since they have no commonality in terms of structure, efforts have been made to develop them individually. Therefore, if these are properly combined, it will be possible to improve the workability of integrating them into a vehicle and reduce the number of parts, and this will also result in structural and functional improvements. If so, its usefulness would be extremely great.

[Purpose of the invention]

The present invention has been made based on this viewpoint, and its object is to provide a device that conveniently integrates a hydro booster and a brake pressure holding device.

Another object of the present invention is to provide a hydrobooster with a brake pressure holding device that allows one solenoid valve to hold the brake pressure for each wheel of a four-wheeled vehicle.

[Summary of the invention]

The features of the hydro booster with a brake pressure holding function according to the present invention, which was made to achieve this purpose, are that the boost piston moves when the brake pedal is depressed, and that the boost piston cooperates with the movement of the boost piston. a valve device that introduces pressure oil from a pressure accumulation source into a control pressure chamber and releases the pressure oil in the control pressure chamber when the boost piston is not moving; and a valve device that generates brake hydraulic pressure under the hydraulic action of the control pressure chamber. A hydraulic booster is provided with a hydraulic cylinder device, and is provided such that the hydraulic pressure in the control pressure chamber acts on the boost piston as a brake pedal depression reaction force, the brake pedal depression force on the boost piston is A hold oil chamber that applies hydraulic pressure in the same direction is provided, and the control pressure chamber and the hold oil chamber are connected via a solenoid valve device that opens in response to a brake pressure holding command.

[Embodiments of the invention]

The present invention will be explained below based on the drawings.

Embodiment 1 Embodiment 1 shown in FIG. 1 will be conveniently explained by comparing it with the conventional hydro booster shown in FIG. 4 which does not have a brake pressure holding function.

First, to explain these common components, the cylinder D1 has a long cylinder 2 with one end open, and a tandem type hydraulic cylinder device for generating brake pressure is built into the bottom side of the cylinder 2. ing. This hydraulic cylinder device is a general one, and includes first and second hydraulic pistons 3.4, first and second return springs 5,
6. Brake hydraulic chambers 7, 8, output ports 9 and 10 for connecting each brake hydraulic chamber 7, 8 and the wheel cylinder of the brake device, reservoirs 11, 12, compensating ports for connecting the reservoir and the brake hydraulic chamber, respectively. port 13,
14, Intake port 15°16 and Vinton cup 1
It consists of 7, 18, 19, and 20.

Further, a hydro booster mechanism is built into the open end side of the cylinder 2 so as to cooperate with the second hydraulic piston 4. In the hydro booster mechanism of this example, a control piston 31 that slides into the cylinder 2 has an inner cylinder 32,
The inner end of a boost piston 33 is slidably fitted to the inner cylinder 32, and the outer end of the boost piston 33 is linked to receive the depression force of a brake pedal 35.

Note that 34 is a return spring that biases the boost piston 33 in the brake pedal return direction. Further, numeral 36 is a stopper ring member that restricts the return position of the boost piston 33, and seals the inside and outside of the cylinder by slidingly fitting the boost piston 33 in a fluid-tight manner.

In addition, the control piston 31 and the boost piston 33 are provided with a spool type valve device by forming the following flow path, thereby allowing the passage between the high pressure chamber A1, the low pressure chamber B, and the control pressure chamber C. It is designed to communicate/block.

That is, an axial flow path 33m is formed in the boost piston 33 so as to open at the inner end, and a portion of this axial flow path 33a1 has a flow path extending toward the circumferential surface of the inner cylinder 32 of the control piston 31. The first radial flow path 3 opens at
3b1 and a second radial flow path 33C that opens into the control pressure chamber C facing the rear end (right end in the figure) of the control piston 31 is formed.

The control piston 31 also includes the boost piston 33.
A first radial flow passage 31m opens into a space in the inner cylinder 32 facing the inner end thereof and also opens into the low pressure chamber B, and the outer circumferential surface of the boost piston 33 that slides into the inner cylinder 32. A second opening towards the high pressure chamber A on the outer periphery.
A radial flow path 31b is formed.

and a second radial passage 3 of said pistons 31, 33.
1b and the first radial flow path 33b are normally (when not braking) K in a blocked state with their openings not facing each other as shown in the figure.
When the boost piston 33 is pushed inward for a certain length, the openings face each other and communicate with each other. Further, when the openings of these radial passages 31b and 33b face each other, the opening of the first radial passage 31& of the control piston 31 is closed by the inner end of the boost piston 33, and the opening of the first radial passage 31& of the control piston 31 is closed by the inner end of the boost piston 33, and The directional flow path 33c is always open to the C chamber.

Therefore, under normal conditions (when not braking), B and C are connected and A is independent, but the boost piston 33
By depressing the brake pedal 35, A
- The communication relationship is switched such that C is connected and B is independent.

The low pressure chamber B is communicated with the reservoir 21 via the port 22, and the high pressure chamber A is communicated with the accumulator 37.
-) 38, the switching of the flow path transmits the high pressure to the control pressure chamber CK, which generates a moving force in the control piston 31, which operates the hydraulic cylinder device to produce a predetermined brake hydraulic pressure. It turns out. Further, since high pressure is applied to the inner end of the boost piston 33, a reaction force is generated when the brake pedal 35 is depressed.

Note that 39 is a ring for pumping pressure oil from the reservoir 21 to the 7-cumulator 37, 40 is a one-way valve; 41 is a transmission path.

The above is the structure of the hydro booster shown in FIG. 4, but the hydro booster according to the embodiment of the present invention shown in FIG. 1 has the following additions in addition to this structure.

That is, in the hydro booster of this example, the stopper ring 36 that engages with the boost piston 36 has a cylindrical shape, and the large diameter shaft portion of the booster piston 33 is slidably fitted to the inner cylinder 36m, and the inner cylinder A hold oil chamber 4D2 is formed at the bottom of the cylinder 36m, from which the stepped shoulder of the booster piston 33 faces. And the small oil chamber is the radial flow path 36b1 port 42 of the stopper ring 36.
is further connected to the control pressure chamber C via a solenoid valve device 44.

Here, the solenoid valve device 44 of this example is of a type in which a normally closed solenoid valve 45 and a return valve 46 that allows the flow of pressure oil in the hold oil chamber D←control pressure chamber C are connected in parallel. The pressure oil in the control pressure chamber C is introduced into the hold oil chamber only when the solenoid valve 45 is opened. The solenoid valve 45 is switched from open to open by using a known brake force holding signal output circuit so that it is operated from open to closed when it is necessary to hold the brake force, and returned from closed to open when the holding is released. (for example, a circuit that outputs a signal when the vehicle is stopped and stops the output at the next generation operation).

According to the above configuration, when pressure oil is introduced into the hold oil chamber, the boost piston 33 is depressed when the brake pedal 35 is depressed due to the depression reaction force acting on the inner end and the force of the return spring 340. Even if the brake pedal is released, it continues to stop at that moving position (because the acting force in the axial direction is balanced), and therefore it is possible to automatically maintain the braking force even when the brake pedal is released.

That is, under normal conditions, the pulp 45 is in an open state, and during braking, the boost piston 33 moves forward and the space in the D chamber increases. When the brake is released, the oil in the D chamber returns to the pulp 45C chamber, 33 e # 33 m + 31 a + D chamber in that order, but when the brake is held, the oil returns to the valve 4 after braking.
Close 5. Even if the pressure on the brake pedal is released in this state, the oil in the D chamber cannot escape anywhere because the valve 45 is closed, and the boost piston cannot return to its original position, so the brake force is maintained. .

FIG. 2 shows another example of the solenoid valve device shown in FIG. There is an advantage of being able to reduce assembly man-hours.

Embodiment 2 The embodiment shown in FIG. 3 is conveniently explained by comparing it with the conventional hydro booster shown in FIG. 5 which has a brake pressure holding function.

This example has substantially the same functions except that the structure of the valve device that switches communication/blocking between oil chambers A, B, and C has been changed from the spool valve type to the poppet valve type in the previous example. Therefore, for convenience of explanation, the same members are shown with 100 added to the reference numerals of the above embodiment, and detailed explanation thereof will be omitted.

Oil chambers A to B-C in the hydro booster mechanism in this example
The valve device for switching between communication and cutoff is constructed as follows. That is, the inner end opening of the axial flow path 133a of the boost piston 133 forms a valve seat 133d,
It is spaced apart and opposed to the poppet 150 in the initial position.

The poppet 150 is normally seated against a valve seat 152 of a valve seat body 151 fixed to the second piston 104 by the spring force of a set spring 153, and the boost piston 133 is connected to a brake pedal (not shown). It is pushed to the inner end side by stepping down, and the inner end hits the poppet 150 (
Therefore, the valve seat 133d of the axial flow path opening of the boost piston 133 comes into contact with the poppet 150 to close the opening), and is separated from the valve seat 152 when further moved.

Therefore, by switching between the contact and separation between the valve seat 150 and the two valve seats 152 and 133d, the high pressure chamber A and the control pressure chamber C shown in the figure are switched from closed to open, and the control pressure chamber C and the low pressure chamber B are switched. is switched from open to closed, and the control pressure chamber C
High pressure is introduced into the hydraulic cylinder, and brake hydraulic pressure is generated in the hydraulic cylinder device.

In the present example shown in FIG. 3, the control pressure chamber C and the hold oil chamber are connected by the same solenoid valve device 144 as in FIG. By restricting the return of the thrust piston 133, the brake force can be maintained even when the brake pedal is released.

That is, normally, the valve 145 is in an open state, and during braking, the boost piston 133 moves forward and the space in the D chamber increases.

When the brake is released, the oil in this D chamber flows into the valve 145;
Oil returns to the chambers C t133c, 133a+131a, and B, but when the brake is held, the valve 145 is closed after braking. Even if the pressure on the brake pedal is released in this state, the oil in the D chamber cannot escape anywhere because the valve 145 is closed, and the booth piston cannot return to its original position, so the brake force is maintained. Ru.

〔Effect of the invention〕

As described above, according to the present invention, by relatively simple improvement of the existing hydro booster, it is possible to automatically maintain the braking force, and in particular, the braking force for the four wheels can be maintained using a single solenoid valve. Since it can be realized by a device, its usefulness is extremely unique.

[Brief explanation of drawings]

1 and 3 are longitudinal sectional views of a hydro booster showing an embodiment of the present invention, FIGS. 4 and 5 are views showing an example of a conventional hydro booster corresponding to the above embodiment, and FIG. The figure is a diagram showing another example of the electromagnetic valve device. 1 Niji cylinder is di 2 Niji cylinder 3.4: Hydraulic piston 5.6: Return spring 7.8 Ni brake oil chamber 9, 10: Output? -G11.
12, 21: Reservoir 13. 14: Competition date 15. 16: Intake port 17. 18. 19, 20: Piston cup 22: f-)
31: Control piston 32: Inner cylinder 33 Nibost piston 34: Return spring 35 Brake pedal 36:
Stopper ring 37: Accumulator 38: Port 39, 42: Date 40 one-way valve
41: Transmission path 44: Solenoid valve device 45
: Solenoid valve 46: Return valve 47: Transmission path 15
0: Poppet 151: Valve seat body 152: Valve seat 153: Set spring procedural amendment December 1960 2 Otsu 1 Relationship to the case Applicant 4, agent Address 2-6-2 Marunouchi, Chiyoda-ku, Tokyo Shigesu Building 330f-::4B:'-,':・' 8. Contents of the amendment Claims as shown in the attached sheet] Moved by stepping down on Zure + Petal
a valve device that cooperates with the movement of the stobist and the stobist υ to introduce pressure oil from a pressure accumulation source into the control pressure chamber, and releases the pressure oil in the control pressure chamber when the stobist is not moving; and a hydraulic system that generates 10 hydraulic pressure under the hydraulic action of the control pressure chamber, and the hydraulic pressure of the control pressure chamber acts as a reaction force when the pedal pedal is depressed against the hydraulic pressure of the control pressure chamber. A hold oil chamber is provided to apply hydraulic pressure in the same direction as the pedal + pedal depression force to the hydraulic brake, and the control pressure chamber and the hold oil are connected to each other. A hydro-starter with a 10-pressure holding function, characterized in that the chambers are connected via a solenoid valve device that closes the circuit in response to a 10-pressure holding command.

Claims (1)

[Claims] A boost piston moves when the brake pedal is depressed, and in cooperation with the movement of this boost piston, pressure oil from a pressure accumulation source is introduced into the control pressure chamber, and when the boost piston is not moving, pressure oil in the control pressure chamber is introduced. and a hydraulic cylinder device that generates brake hydraulic pressure in response to the hydraulic action of the control pressure chamber, and the hydraulic pressure of the control pressure chamber acts on the boost piston as a reaction force when pressing the brake pedal. In the hydro booster, a hold oil chamber is provided that applies hydraulic pressure in the same direction as the brake pedal depression force to the boost piston, and a brake pressure is maintained between the control pressure chamber and the hold oil chamber. A hydro booster with a brake pressure holding function, characterized in that it is connected via a solenoid valve device that opens in response to a holding command.