JPH02212254A - Stoppage holding device of vehicle - Google Patents

Abstract

PURPOSE:To prevent generation of impact noise by operating an electromagnetic valve to be turned on and off to gradually discharge pressurized fluid in a pressure changing chamber at the time of opening the electromagnetic valve in a device that brake operating condition is maintained by shutting off a line in a brake booster by means of the electromagnetic valve. CONSTITUTION:A brake booster (A), when a brake pedal is stepped on to move a valve plunger 13 forward, shuts off between a vacuum line 8 and an atomosphere line 9 by means of a valve mechanism 7 and communicates the atomosphere line 9 and an atomosphere line 10 to move a power piston 2 forward due to differential pressure between a pressure changing chamber 5 and a pressure constant chamber 4. And an electromagnetic valve 21 is closed to shut off the vacuum line for maintaining a brake under braking condition. In this case, when it is judged that operational conditions to open the electromagnetic valve 21 is effected in the operation judging unit 31 in a control unit 28, indicating voltage is output from an opening and closing drive unit 35 to a constant current circuit 28 to on-off-control electricity applied to the solenoid coil 22 of the electromagnetic valve 21 for gradually discharging pressure in the pressure charging chamber 5.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a vehicle stop holding device, and more particularly to a vehicle stop holding device using a brake booster.

``Prior Art'' Conventionally, a solenoid valve that opens and closes a vacuum passage is attached to a pulp body as a stop-holding device for a vehicle using a brake booster l. It is known that when the conditions are met, the brake booster is maintained in the operating state by closing the solenoid valve, thereby allowing the brake operating state tm to continue even if the brake pedal is released. (Japanese Unexamined Patent Publication No. 62-279164).

In other words, a negative pressure brake booster generally consists of a power piston that is slidably disposed within a shell, a valve mechanism that is housed in a pulp body in the area of the power piston, and a valve mechanism located on the front side of the power piston in the operating direction. A constant pressure chamber is formed and into which negative pressure is always introduced; a variable pressure chamber is formed on the dipping side and into which atmospheric pressure is introduced; and the constant pressure chamber and variable pressure chamber are formed in the pulp body and communicate through the valve mechanism. an input shaft that operates a valve plunger constituting the valve mechanism to switch the flow path, supplies atmospheric pressure to the variable pressure chamber, and advances the power piston; and an output shaft linked to the above-mentioned pulp body, so that the depression force applied to the above-mentioned input shaft via the brake pedal can be boosted, and a strong braking action can be performed with a light depression force. It has become.

In a vehicle stop holding device using this type of brake booster M%, a solenoid valve is disposed within the constant pressure chamber and attached to the pulp body, and the solenoid valve connects to the constant pressure chamber via the valve mechanism. A vacuum passage communicating with the variable pressure chamber is opened and closed.

In a stop holding device with such a configuration, by opening the solenoid valve, the same operation as a normal brake booster can be obtained, and when the brake is applied and the vehicle is stopped, the required amount of force is applied. If the solenoid valve is closed when the conditions are met, the solenoid valve will remain closed even if the brake action is released and the variable pressure chamber and constant pressure chamber are attempted to communicate through the valve mechanism and passage. Therefore, the atmospheric pressure introduced into the variable pressure chamber cannot escape to the negative pressure source via the constant pressure chamber. Therefore, even if the pedal force is released from the brake pedal, the braking action can be continued.

``Problem to be Solved by the Invention'' Conventionally, when the solenoid valve is closed and the vehicle is held in a stopped state, when the held state is released, the current that has been energized to the solenoid coil of the solenoid valve is simply connected. It was disconnected.

However, if this is done, the pulp body, input shaft, brake pedal, etc. that were held in the forward position while the vehicle is stopped will quickly return to the non-operating position, causing the noise of collision between the key member and the shell and the brake pedal. A collision noise between the pedal and its stopper may occur.

"Means for Solving the Problem" In view of such circumstances, the present invention is provided in a pulp body of a brake booster, and maintains the brake booster M in a brake operating state by closing a passage formed in the pulp body. In a vehicle stop holding device comprising a solenoid valve and a control device that closes the passage by applying current to a solenoid coil of the solenoid valve, the control device is configured to energize the solenoid coil when the solenoid valve is opened. An opening/closing drive unit is provided to perform ON-OFF control to open and close the solenoid valve.

"Operation" According to the above configuration, the opening/closing drive section of the control device opens and closes the solenoid valve when the solenoid valve is opened, so that the pressure fluid such as atmospheric air introduced into the pressure transformation chamber of the brake booster gradually It will be discharged into a constant pressure chamber. As a result, the pulp body, input shaft, brake pedal, etc. gradually return to their non-operating positions, and it is therefore possible to suppress the collision noise that would otherwise be caused by their sudden return to their non-operating positions. It becomes possible.

``Example'' The present invention will be described below based on an illustrated example. In FIG. 1, a power piston 2 is slidably provided in a shell 1 of a brake booster A, and a A diaphragm 3 is stretched, and the power piston 2 and diaphragm 3 partition the inside of the shell 1 into a constant pressure chamber 4 at the front and a variable pressure chamber N5 at the rear.

Pulp body provided in detail of the power piston 2, 6
A valve mechanism 7 is housed inside, and this valve mechanism 7 includes a vacuum passage 8 communicating with the constant pressure chamber 4, an atmospheric passage 9 communicating with the variable pressure chamber 5, and an atmosphere introduction passage roughly communicating with the atmosphere. The state of communication with the passage 10 is switched and controlled.

The plunger 13 constituting the valve mechanism 7 is the key member 1
4 prevents it from coming out of the pulp body 6, and its distal end is connected to an input shaft 15 that is linked to a brake pedal (not shown), and the tip surface of the valve plunger 13 is connected to the bushing rod 1 through a rear crayon disc 16.
It is linked to 7.

The power piston 2, pulp body 6, etc. are normally held in the non-operating position 1 shown in the figure by a return spring 18, and in this state, the valve mechanism 7 communicates the vacuum passage 8 with the atmosphere passage 9, and the atmosphere passage 9 and the atmosphere introduction passage 10, thereby cutting off the communication between the negative pressure introduction pipe 1
The negative pressure that is constantly introduced into the constant pressure chamber 4 through the vacuum passage 9 is introduced into the variable pressure chamber 5 through the vacuum passage 8 and the atmospheric passage 9.

On the other hand, when the brake pedal is depressed and the well plunger 13 is moved forward, the valve mechanism 7 disconnects the communication between the vacuum passage 8 and the atmosphere passage 9, and also connects the atmosphere passage 9 and the atmosphere introduction passage 10. As a result, the atmosphere is introduced into the variable pressure chamber 5 from the atmosphere introduction passage 10 through the atmosphere passage 9, so that the power piston 2, pulp body 6, etc. are moved forward against the return spring 18. .

Therefore, the solenoid valve 2 for maintaining the brake in the operating state
1 is disposed in the constant pressure chamber 4 and attached to the pulp body 6 at a position outside and below the return spring 18, and the solenoid coil 22 of the solenoid valve 21 is energized to attract and operate the valve body 23. In some cases, the vacuum passage 8 can be closed by seating the valve body 23 on the valve seat 25 against the spring 24.

The harness 26 drawn out from the solenoid coil 22 is kept airtight by the sealing means 27 and drawn out of the shell 1, and then passed through the constant current circuit 28 to the solenoid valve 21.
It is connected to a control device 29 consisting of a microcomputer or the like that controls opening and closing.

It is clear that when the electromagnetic valve 21 is maintained in the open state, the brake can be operated by depressing and releasing the brake pedal, similar to conventional brake boosters. On the other hand, if the solenoid valve 21 is operated to close the vacuum passage 8 in the operating state of the brake booster A when the brake pedal is depressed, the pressure will change even if the brake pedal is subsequently released. The pressure fluid in the chamber 5 cannot escape to the constant pressure chamber 4, and the power piston 2, pulp body 6, etc. are maintained at the same position even if they are in the operating position, and the brake operating state is maintained.

Next, the control device 129 determines whether or not the operating condition for closing the electromagnetic valve 21 and the release condition for opening the electromagnetic valve 21 are satisfied. The operation determination unit 31 includes a brake switch 32 that detects whether the brake pedal is depressed, a clutch switch 33 that detects that the clutch is engaged, and a push-button switch that activates the stop holding device. The signal from the activation switch 34 is input. .

The operation determination section 31 operates to close the solenoid valve 21 when the operation switch 34 is pressed by the driver while the brake switch 32 detects that the brake pedal is depressed. It is determined that the conditions are satisfied, and when it is detected that the clutch is connected by the clutch switch 33 in the stopped state, it is determined that the release condition for opening the solenoid valve 21 is satisfied. It looks like this.

When the operation determination section 31 determines that the operation condition is satisfied, the operation determination section 31 controls the opening/closing drive section 35 of the control device 129.
outputs a command voltage to the constant current circuit 28, and when the command voltage is applied, the constant current circuit 28 energizes the solenoid coil 22 with a constant value of current according to the magnitude of the command voltage, and closes the solenoid valve 21. let Note that the opening/closing drive section 35
After the valve body 23 is seated on the valve seat 25, the constant current circuit 28
By lowering the instruction voltage to the constant current circuit 28 and lowering the constant current value supplied to the solenoid coil 22 from the constant current circuit 28, it is possible to prevent the solenoid coil 22 from burning out.

Roughly speaking, when the operation determination section 31 determines that the release condition is satisfied from the closed state of the solenoid valve 21, the operation determination section 31 stops the excitation of the solenoid coil 22 by the opening/closing drive section 35 and closes the valve body of the solenoid valve 21. 23 is opened by a spring 24.

At this time, when the above-mentioned release condition is satisfied as shown in FIG. 2, the opening/closing drive section 35 energizes the solenoid coil 22 at time T1 (v!). However, after a predetermined time T1, which is shorter than the time required for the pulp body 6, input shaft 15, brake pedal, etc. to return to their non-operating positions, the pressure introduced into the variable pressure chamber 5 has decreased to a certain level, the solenoid The electromagnetic valve 21 is controlled to open and close by ON-OFF controlling the energization of the coil 22.

Further, when the opening/closing drive unit 35 detects that the pulp body 6, input shaft 15, brake pedal, etc. have returned to the non-operating position based on a signal from the brake switch 32, it completely cuts off the energization to the solenoid coil 22. It looks like this.

In the above configuration, when the operation determination unit 31 of the control device 29 determines that the operation condition for closing the solenoid valve 21 is satisfied, that is, the brake switch 32 detects that the brake pedal is depressed. In this state, when the operation switch 34 is pressed by the driver, the operation determination unit 31 outputs this to the opening/closing drive unit 35, and the opening/closing drive unit 35 starts energizing the solenoid coil 22. The solenoid valve 21 is closed, and the vehicle is brought to a stopped state as described above.

Next, when it is detected that the clutch is connected by the clutch switch 33 after a hill start is performed without any problem from the stopped state, the operation determination section 31 determines that the release condition is satisfied and It is output to the opening/closing drive unit 35.

Then, the opening/closing drive unit 35 disconnects the energization to the solenoid coil 22 for the predetermined time T1 and opens the solenoid valve 21, so that the pressure in the variable pressure chamber 5 is reduced to the constant pressure chamber 4 via the vacuum passage 8. The pressure inside the variable pressure chamber 5 drops rapidly.

As a result, the pulp body 6, input shaft 15, brake pedal, etc. are rapidly returned from the operating position toward the non-operating position by the return spring 18.

When the predetermined time T has elapsed, the opening/closing drive unit 35 controls the solenoid coil 22 to be energized (tON-OFF) to open/close the solenoid valve 21, thereby causing the valve body 23 of the solenoid valve 21 to move toward the valve seat. 25 is repeatedly brought into and out of contact with the variable pressure chamber 5, so that the pressure inside the variable pressure chamber 5 gradually decreases.

As a result, the pulp body 6, input shaft 15, brake pedal, etc. are gradually returned to their non-operating positions, so the noise of collision between the key member 14 and the shell 1, and the collision between the brake pedal and its stopper is heard. This makes it possible to suppress the occurrence of

On the other hand, since the above-mentioned 0N-OFF control was not performed in the past, there was a risk that the input shaft 15 etc. would suddenly return to the non-operating position as shown by the imaginary line in Fig. 2, causing the above-mentioned collision noise. there were.

Further, when it is detected by the brake switch 32 that the pulp body 6, input shaft 15, brake pedal, etc. have been returned to the substantially non-operating position, the opening/closing drive section 3
5 completely cuts off the current to the solenoid coil 22.

Note that instead of setting the predetermined time T, the pressure in the variable pressure chamber 5 may be detected, and when the pressure falls below a predetermined value, ON-OFF of the solenoid valve 21 may be started, or the input Actuation value of axis 15 or brake pedal! lFr may be detected, and when the position becomes a predetermined position with respect to the non-operating position, 0N-OFF IIJ control of the solenoid valve 21 may be started.
FilJID may be stopped and the solenoid valve 21 may be opened after a predetermined period of time has elapsed.

"Effects of the Invention" As described above, according to the present invention, when the solenoid valve is opened, the opening/closing driving section of the control device opens and closes the solenoid valve to remove atmospheric air, etc. introduced into the pressure transformation chamber of the brake booster. Since the pressure fluid is gradually discharged into the constant pressure chamber, it is possible to gradually return the pulp body, input shaft, brake pedal, etc. to the non-operating position. This provides the effect of suppressing the occurrence of collision noise.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention, and FIG. 2 is a characteristic diagram illustrating the operating state. 6...Pulp body 21--Solenoid valve 23--Valve element 29--Control device 35--Opening/closing drive section 8-Passage 22-Solenoid coil 25-Valve seat 31--Operation determination section A...・Brake booster patent applicant Jidosha Kiki Co., Ltd.

Claims (1)

[Claims] A solenoid valve that is provided in the pulp body of the brake booster and closes a passage formed in the pulp body to maintain the brake booster in a brake operating state, and a solenoid coil of the solenoid valve that is energized. and a control device for closing the passage, wherein the control device includes an opening/closing drive for opening and closing the solenoid valve by controlling ON/OFF energization of the solenoid coil when the solenoid valve is opened. What is claimed is: 1. A vehicle stoppage holding device, characterized in that a vehicle stoppage holding device is provided with a section.