JPS6239355A - Hydrobooster with brake pressure holding function - Google Patents

Abstract

PURPOSE:To make it possible to hold a braking power automatically, by furnishing a hold oil room to control the oil pressure in the direction of a brake oil pressure generation, at an oil pressure cylinder unit for brake oil pressure generation in a hydrobooster, and furnishing an electromagnetic valve in the hold oil room. CONSTITUTION:In a long size cylinder 2 of a cylinder body 1 is incorporated a tandem type rake master cylinder unit including the first and the second hydraulic pistons 3 and 4, while at the opening end side of the cylinder 2 is incorporated a hydrobooster mechanism. This mechanism consists of a control piston 31 sliding in the cylinder 2, an inner tube cylinder 32 inside the control piston 31, and a boost piston 33 sliding in the inner tube cylinder 32 with its inner end, and the pressing power of a brake pedal 35 is inflicted to the piston 33. Moreover, a low-pressure room B formed between the control piston 31 and the second piston 4 is connected to a pump 39 or a reserver 21 through a port 48, a delivery route 49, and an electromagnetic valve unit 50 convertible downward in a brake pressure holding condition.

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]

Conventionally, various hydraulic pressure boosters (hydro boosters) have been provided as brake force boosters for vehicle braking systems. A so-called brake pressure holding device has also been provided which holds the pressure until the vehicle starts moving.

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

[Purpose of the invention]

The present invention has been made from this perspective, 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 hydropressure booster equipped 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]

Therefore, the features of the hydro booster with a brake pressure holding function υ according to the present invention, which has been made to achieve the above object, are as follows.
A boost piston moves depending on the force applied to the brake pedal, and in cooperation with the movement of this boost piston, pressurized oil from the pressure accumulation source is introduced into the control pressure chamber, and when the boost piston is not moving, it is moved into the control pressure chamber. a control piston that is moved depending on the hydraulic action of the control pressure chamber; and a hydraulic cylinder device that is linked to the control piston and generates brake hydraulic pressure by transmitting a moving force from the control piston. In a hydro booster equipped with a hydraulic booster, a hold oil chamber is provided in the hydraulic cylinder device to which hydraulic pressure can be applied in the direction of generating brake pressure, and this hold oil chamber normally releases indoor hydraulic pressure and is required to hold brake pressure. This is where the solenoid valve device that introduces the pressure oil from the pressure accumulation source is connected.

[Embodiments of the invention]

The present invention will be described below based on embodiments shown in the drawings.

Embodiment 1 In Fig. 1, 1 is a cylinder M having 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. 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, and each brake hydraulic chamber. 7, 8, output ports 9, 10 for connecting the wheel cylinder of the brake device, and a reservoir 11.
12, compensating ports 13 and 14 that connect the reservoir and brake hydraulic chamber, respectively, inch-kund 15,
16, Bintonka f17°18.19,20 b.

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 the boost piston 33 is slidably fitted to this inner cylinder 32. fi, the outer end of the boost piston 33 is linked so as to receive the depression force of the brake pedal 35. Note that 34 is a return spring that presses and biases the boost piston 33 in the brake pedal return direction. The cylinder 36 is a stone ring member that restricts the return position of the boost piston 33, and seals the inside and outside of the cylinder by liquid-tightly sliding together with the boost histone 33.

In addition, the control piston 31 and the boost piston 33 are provided with a Sgur type valve device by forming the following flow path, thereby providing a gap between the high pressure chamber A, the low pressure chamber B, and the control pressure chamber C. It is designed to connect and block communication.

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

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 radial flow path 31b is formed that opens toward the high pressure chamber A on the outer periphery.

And the second radial flow path 3 of both the pistons 31 and 33
1b and the first radial flow path 33b are in a state of being blocked, with the openings not facing each other as shown in the figure, normally (when the brake is not applied).
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 are opposite to 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. The flow path 33c is always open to the C chamber.

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

The high-pressure member includes a circumferential groove 31c provided on the outer periphery of the axis of the control piston 31 and having a constant length in the generatrix direction and the cylinder 2.
It is connected to the achievator 37 via a boat 38. Furthermore, a one-way valve 40 and a pump 39 are connected to this achievable mulletator 37.
Pressure oil is transferred from the reservoir 21 through the transmission path 41.
The water is pumped up to the pump tank 37 and supplied to high-pressure households.

The low pressure chamber B is provided as an oil chamber in the cylinder 2 facing the front end of the control piston 31 and the rear end of the second piston 4 of the hydraulic cylinder device, and is connected to the boat 48, the transmission path 49, and the electromagnetic valve described later. Reservoir 21 via device 50
It is connected to the.

Furthermore, the control pressure chamber C is formed as an oil chamber facing the rear end of the control piston 31 and surrounded by the outer periphery of the boost piston 33 and the cylinder 2. It is designed to apply hydraulic pressure to press the piston 4. Furthermore, due to the above-mentioned configuration, pressure oil having the same pressure as that of the control pressure chamber C is transmitted to the inner end (front end) of the boost piston 33, so that the boost piston 33 has a pressure corresponding to the pressure under the brake pedal path. to act.

It is assumed here that the solenoid valve system [1i50] described above is always maintained in the hydraulic release mode shown.

Normally, the brake (if there is no flow to the barrel 35), the boost piston 33 is biased to the initial position shown, and the control pressure chamber C and the low pressure chamber B are communicated, and the side split piston 31 is connected to the hydraulic cylinder. No force is generated to press the second hydraulic piston 4 of the device.Therefore, no brake oil pressure is generated.At this time, the high pressure chamber A is isolated from the oil chamber C.

Next, when the brake pedal 35 is depressed by a brake operation, the boost piston 33 is pushed in and moves relative to the control piston 31. For this reason, each of the above-mentioned radial flow passages 31m, 31b.

The communication relationship of the valve device formed by 33b and 33c is switched, first, the oil chamber B-C is blocked by blocking the opening of the radial flow path 31m, then the radial flow path 31b,
Communication between the high pressure chamber A and the control pressure chamber C occurs through the opposing openings of the high pressure chamber A, and pressurized oil from the high pressure chamber A is introduced into the control pressure chamber C. The pressurized oil at this time acts on the boost piston 33 as a road reaction force to the brake pedal, and when the pedal depression force and the road reaction force are balanced, the radial flow path 31
b and 33b are shifted from each other, and the introduction of pressure oil is cut off. Therefore, the control pressure chamber CK receives hydraulic pressure depending on the force of pressing the brake pedal (brake), and through the movement of the control piston 31, In each brake oil chamber 7, 8 of the hydraulic cylinder device,
A predetermined brake oil pressure is generated respectively.

The above operation is almost the same as that of the conventional hydropousta.

In contrast, in this example, a solenoid valve device 50 is provided in the hydraulic pressure release path of the low pressure chamber B, and this solenoid valve device 50 is connected to the low pressure chamber B.
A trap is installed so that the connection of the pressure accumulating source (in this example, the achievable regulator 37) can be switched. This switching of the solenoid valve device 50 is performed when a signal is input from a brake pressure hold signal output circuit (not shown). A known circuit may be used that starts outputting a signal and then stops the output when the next vehicle start operation is performed (such as when the accelerator pedal is detected on the road). By adding the solenoid valve device 150 described above, the low pressure chamber B has a function as a hold oil chamber into which the pressure oil of the achievator 37 is introduced when necessary, and by introducing the pressure oil, the second hydraulic piston of the hydraulic cylinder device 4 includes a control piston 31
In addition to the force transmitted from Even if the vehicle returns to its original position, the state in which the brake oil pressure is generated in the hydraulic cylinder device is maintained as it is, and the maintenance of the so-called automatic braking state, which cannot occur when the vehicle is stopped, is achieved.

Embodiment 2 In the embodiment shown in FIG. 2, a proportional electromagnetic pressure reducing valve 51 is branch-connected to the transmission path 49 between the low pressure chamber (hold oil chamber) B and the electromagnetic valve device 50. (Here, 21
' is a front singel, which is a common reservoir with the reservoir 21) and this proportional type electromagnetic pressure reducing valve 5.
Embodiment 1 is different from Embodiment 2 in that the pressure in Embodiment 1 is controlled by a controller 52 that includes a brake pressure hold signal output circuit that controls the operation of a solenoid valve device 50, but the other configurations are the same as in Embodiment 2. It is exactly the same as 1.

The controller 52 of this example uses an electromagnetic pressure reducing valve, for example, by using an external human power to control the brake pedal on the road, or by using an output from an inclination sensor as an external input when the road surface where the vehicle is stopped is on a slope. This is done by varying the control current or voltage applied to the solenoid 51 to reduce the holding brake pressure to a necessary and sufficient level. According to this, excessive brake pressure is not often held in the low pressure chamber B, which is effective in improving the durability of the sealing member and the like.

As can be understood from the above-described embodiments of the present invention, the brake pressure can be maintained by switching the operation of the solenoid valve device 50, and the proportional solenoid pressure reducing valve 51 changes the current or voltage depending on the signal from the controller. By varying the pressure, the set pressure can be changed arbitrarily, so it is possible to control the brake according to the required pressure at the required time using a signal from the controller. This not only maintains the brake pressure, which normally occurs when the vehicle is stopped, but also prevents rear-end collisions by automatically applying the brakes when the risk of rear-end collision or collision is detected. Another advantage is that it can be applied to molds.

〔Effect of the invention〕

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

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a hydro booster showing a first embodiment of the present invention, and FIG. 2 is a longitudinal sectional view of the same according to a second embodiment. 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 port 11.1
2, 21: Reservoir 13. 14: Compensating port 15. 16: Intake boat 17. 18, 19, 20: Piston cup 22: Reservoir 31; Control piston 32: Inner cylinder
33 Nibost piston 34: Return spring 35 Ni brake pedal 36: String 37: Aki, -muleta 38: Port 39: Bon f
40 one-way valves 41, 49: transmission path

Claims (1)

[Claims] A boost piston moves depending on the force applied to the brake pedal, and in cooperation with the movement of this boost piston, pressure oil from the pressure accumulation source is introduced into the control pressure chamber, and when the boost piston is not moving, the control pressure chamber a control piston that is moved depending on the hydraulic action of the control pressure chamber; and a hydraulic cylinder device that is linked to the control piston and generates brake hydraulic pressure by transmitting a moving force from the control piston. In the hydraulic booster, the hydraulic cylinder device is provided with a hold oil chamber capable of applying hydraulic pressure in the direction of generating brake pressure, and the hold oil chamber is normally released from the indoor hydraulic pressure, and when it is necessary to hold the brake pressure, the hold oil chamber is A hydro booster with a brake pressure holding function, characterized in that it is connected to a solenoid valve device that introduces pressure oil from a pressure accumulation source.