JPH0584263B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a hydrobooster for a vehicle brake system, and more specifically, it maintains brake fluid pressure in a vehicle that has stopped due to braking until the next time the vehicle starts moving. It relates to a hydraulic booster with a device.

(Prior Art) Conventionally, various hydraulic pressure boosters (hydro boosters) have been provided as brake force boosters for vehicle braking systems. There have also been provided so-called brake pressure holding devices that hold the brake pressure until the next start of the vehicle.

By the way, each of these is intended to serve a completely different purpose, and since they have no commonality in terms of structure, each of them has been individually devised.

(Problem to be solved by the invention) However, since they are applied to a common object, the brake system of a vehicle, if they are combined well, it will be possible to improve the ease of assembly into a vehicle and reduce the number of parts. If a reduction can be obtained, and furthermore, structural and functional improvements can be achieved thereby, the usefulness will be extremely large.

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.

(Means for Solving the Problems) The feature of the hydro booster with a brake pressure holding function according to the present invention, which was made to achieve the above object, is that it can be moved from its initial position by pressing down on the brake pedal. A boost piston that is
a valve device that cooperates with the movement of the boost piston 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 boost piston is at an initial position; A hydraulic cylinder device that generates a braking force proportional to the hydraulic pressure introduced into the hydraulic booster, and an oil chamber that causes the hydraulic pressure in the control pressure chamber to act on the boost piston as a reaction force when pressing the brake pedal. , 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 circuit is closed between the hold oil chamber and the control pressure chamber by a brake pressure holding command. It is connected via a normally open solenoid valve device.

(Function) According to the above configuration, by simply adding a simple solenoid valve device to a conventionally known hydrobooster, the braking force can be maintained when the vehicle is stopped without interfering with the functions of the conventional hydrobooster. can.

(Example) 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, a cylinder body 1 having a long cylinder 2 with one end open has a built-in tandem type hydraulic cylinder device for generating brake hydraulic pressure on the bottom side of the cylinder 2. There is. 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, 10 for connecting each brake hydraulic chamber 7, 8 to the wheel cylinder of the brake device, reservoirs 11, 12, Compensating ports 13 and 14 that connect the reservoir and brake hydraulic chamber, respectively, intake port 15,
16 and pinton cups 17, 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. The hydro booster mechanism of this example has a control piston 31 that slides into the cylinder 2.
has an inner cylinder 32, and this inner cylinder 3
The inner end of the boost piston 33 is slidably fitted to the brake pedal 2, and the outer end of the boost piston 33 is linked to receive the force of pressing down on 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. Further, 36 is a stop ring member that restricts the return position of the boost piston 33.
The inside and outside of the cylinder are sealed by liquid-tight sliding engagement with the boost piston 33.

Further, the control piston 31 and the boost piston 33 are provided with a spool type valve device by forming the following flow passages, whereby the high pressure chamber A and the low pressure chamber B are mutually controlled. The pressure chambers C are communicated with each other and cut off from each other.

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

The control piston 31 also has a first radial passage 31a that opens into a space in the inner cylinder 32 facing the inner end of the boost piston 33 and also opens into the low pressure chamber B; A second radial flow path 3 opens toward the outer circumferential surface of the boost piston 33 that slides into the outer circumferential high pressure chamber A.
1b is formed.

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

Therefore, normally (when not braking), B to C are in communication and A is in an independent state, but when the boost piston 33 is pressed by pressing down on the brake pedal 35, A to C are communicated and The communication relationship will be switched to make B independent.

Since 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 via the port 38, the flow paths can be switched (that is, A to C may be communicated with each other). ,
(by blocking B), high pressure is transmitted to the control pressure chamber C, generating a force to move the control piston 31 to the left in the figure, and operating the hydraulic cylinder device to generate a predetermined brake hydraulic pressure. become.
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 pump that pumps pressure oil from the reservoir 21 to the accumulator 37, 40 is a one-way valve, and 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 boost piston 33 is slidably fitted onto the inner cylinder 36a, and a hold oil chamber D is formed in which the stepped shoulder portion of the boost piston 33 faces the bottom of the inner cylinder 36a. It is being formed. The hold oil chamber D is connected to the control pressure chamber C through the radial passage 36b of the stopper ring 36, the port 42, and the solenoid valve device 44.
It is connected to the.

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 from the hold oil chamber D←control oil chamber C are connected in parallel. It consists of a solenoid valve 45
The pressure oil in the control pressure chamber C is introduced into the hold oil chamber D only when the circuit is opened. In addition, the solenoid valve 45
The closed←→open switching is performed using a known brake force holding signal output circuit (e.g. It is controlled by a circuit that outputs a signal when the vehicle is stopped and stops the output at the next generation operation.

According to such a configuration, when pressure oil is introduced into the hold oil chamber D, the boost piston 33 is moved by the hydraulic pressure that acts on the inner end and becomes a depression reaction force, and the force of the return spring 34. , even if the brake pedal 35 is released, it continues to stop at that moving position (because the acting force in the axial direction is balanced), so even when the brake pedal is released, the movement continues automatically. This makes it possible to maintain braking force.

That is, under normal conditions, the solenoid valve 45 is in an open state.
During braking, the boost piston 33 moves forward, increasing the space in the D chamber. When the brake is released, the oil in this D chamber flows through the solenoid valve 45, C chamber, 33c, 33a,
Pressure oil returns to chamber 31a and chamber B in this order, but when the brake is held, the solenoid valve 45 is closed after braking, so even if the force to press the brake pedal is released in this state,
Since the solenoid valve 45 is closed, the pressure oil in the D chamber cannot escape anywhere, and therefore the boost piston cannot return to its original position, so the braking force is maintained.

FIG. 2 shows another example of the solenoid valve device shown in FIG. There is an advantage that the number of man-hours required for assembling hydraulic piping can be reduced.

Embodiment 2 The embodiment shown in FIG. 3 will be conveniently explained by comparing it with the conventional hydro booster shown in FIG. 5 which does not have 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 of the previous example to the poppet valve type. 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 chamber A in the hydro booster mechanism in this example
The valve device for switching communication/cutoff of ~B~C is configured as follows. That is, the inner end opening of the axial flow path 133a of the boost piston 133 forms a valve seat 133d, and is spaced apart and opposed to the poppet 150 in the initial position. Further, this 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 pressed against a brake pedal (not shown). The boost piston 133 is pushed toward the inner end side by the lower part, and its inner end abuts the poppet 150 (therefore, the valve seat 133d of the axial flow path opening of the boost piston 133 abuts the poppet 150 and closes the opening). , when further moved, the valve seat 152 is separated from the valve seat 152.

Therefore, by switching between the contact and separation of the poppet 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 closed.
The control pressure chamber C and the low pressure chamber B are switched from open to closed, and high pressure is introduced into the control pressure chamber C.
Brake oil 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 D are connected by the same normally open type solenoid valve device 144 as in FIG. By introducing pressure oil into the brake pedal, the return of the boost piston 133 is restricted, and the brake force can be maintained even when the brake pedal is released.

That is, under normal conditions, the solenoid valve 145 is in an open state, and during control, 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 solenoid valve 145, C chamber, 133C, 133.
The oil returns to chambers a, 131a, and B in this order, but when the brake is held, the solenoid valve 145 closes after braking. 145 is closed, there is no way to escape, and the boost piston cannot return to its original position, so the braking force is maintained.

(Effects of the Invention) As described above, according to the present invention, automatic retention of brake force (brake force retention when stopped) is achieved by adding a relatively simple configuration to an existing hydro booster. The effect is that it becomes possible.

In particular, when a four-wheeled vehicle is stopped, the required braking force can be easily maintained by adding a single solenoid valve device to the hydro booster, which is extremely useful. There is something.

[Brief explanation of the drawing]

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...Cylinder body, 2...Cylinder, 3,
4... Hydraulic piston, 5, 6... Return spring, 7, 8... Brake oil chamber, 9, 10... Output port, 11, 12, 21... Reservoir, 1
3,14……Competitive port, 15,1
6...Intake port, 17, 18, 19, 2
0... Piston cup, 22... Port, 31...
...Control piston, 32...Inner cylinder, 33...
...Boost piston, 34... Return spring, 35... Brake pedal, 36... Stopper ring, 37... Accumulator, 38... Poteau, 39, 42... Port, 40... One-way valve, 41... Transmission path, 44...Solenoid valve device, 4
5... Solenoid valve, 46... Return valve, 47... Transmission path, 150... Poppet, 151... Valve seat body, 152... Valve seat, 153... Set spring.

Claims (1)

[Claims] 1 A boost piston is moved from its initial position by pressing down on the brake pedal, 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 this boost piston returns to its initial position. At some point, the control pressure chamber is provided with a valve device that releases the pressure oil in the control pressure chamber and a hydraulic cylinder device that generates a braking force proportional to the hydraulic pressure introduced into the control pressure chamber, and the hydraulic pressure in the control pressure chamber is applied to the boost piston. In a hydro booster equipped with an oil chamber that acts as a brake pedal depression reaction force on the boost piston, a hold oil chamber is provided that applies hydraulic pressure in the same direction as the brake pedal depression force to the boost piston. A hydro booster with a brake pressure holding function, characterized in that the hold oil chamber and the control pressure chamber are connected via a normally open electromagnetic valve device that is closed in response to a brake pressure holding command.