JPH08188133A - Brake system equipped with automatic braking device - Google Patents

Abstract

PURPOSE: To operate an automatic brake surely at the time of operation of a normal brake as well as to enable it to operate this normal brake surely at the time of the operation of the automatic brake. CONSTITUTION: With the output of a vacuum servo unit, a second piston 9 moves to the left and a second valve 31 closes, and further a first piston 8 moves to the left and a first valve 22 closes as well. Master cylinder pressure in both first and second liquid chambers going up by additional movements of both these pistons 8 and 9 is fed to each wheel cylinder (W/C), whereby a normal brake operates. In addition, a thrust generator 3 is operated by an electronic control unit 47 and thereby a third piston 10 moves to the right and the first valve 22 closes, and also the first piston 8 moves to the right and the second valve 31 closes, whereby the generating pressure is fed to the wheel cylinder, so an automatic brake operates. If the thrust generator 3 operates at the time of the operation of the normal brake, the automatic brake operates, and if a brake pedal is operated at the time of the operation of the automatic brake, the normal brake operates.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention makes it possible to easily start a vehicle, such as an automobile, on a slope, and to eliminate the need to wait for a signal or to continue to depress the brake pedal on a congested road. In order to control the traction during idling of the vehicle, to keep the vehicle stopped on a slope, to control the distance between vehicles while traveling, to suppress the traveling speed of the vehicle such as overspeed prevention on a downhill, or on the side The present invention relates to a brake system including an automatic braking device used to prevent forgetting to apply a brake.

[0002]

2. Description of the Related Art Recently, in automobiles, it is possible to easily start a vehicle such as an automobile on a slope without requiring a sudden pedal change operation from a parking brake or a brake pedal to an accelerator pedal. For,
In order to reduce the fatigue caused by brake operation by eliminating the need to operate the brake pedal while waiting for traffic lights and in congested roads, traction control should be performed when the drive wheels run idle to ensure proper start and acceleration. In order to ensure that the vehicle is stopped on a hill, the inter-vehicle distance is automatically controlled while driving, and the vehicle traveling speed is controlled to prevent overspeed on a downhill. Brake systems have been developed that are equipped with an automatic braking device that is used to automatically prevent the vehicle from forgetting to apply the side brakes.

As a brake system provided with such an automatic brake device, a conventional brake system as shown in FIG.
There is a brake system disclosed in Japanese Patent Publication No. 292256.

The brake system shown in FIG. 6 is equipped with a tandem type vacuum booster. In this state, the vacuum booster 150 has a chamber mechanism in which the atmosphere valve 151a of the valve mechanism 151 is closed and the vacuum valve 151b is opened. A vacuum is introduced to A, B, C, and D, and the brake is in a non-operating state. Further, the solenoid valve 152 is normally set to the position shown in the figure,
Therefore, a vacuum is normally introduced into the chamber A ′ surrounded by the bellows 153.

When the brake pedal (not shown) is depressed and the input shaft 54 moves forward during normal braking in this brake non-operating state, the atmospheric valve 151 of the valve mechanism 151.
Since a is opened and the vacuum valve 151b is closed, the atmosphere is introduced into the variable pressure chambers B and D through the variable pressure passages 155 and 156, respectively. As a result, a differential pressure is generated between the chambers A, B and C, D before and after the diaphragms 157, 158, the diaphragms 157, 158 and the power pistons 159, 160 move forward, and an output is generated from the output shaft 161. The master cylinder 162 is operated by the output, and the normal brake is operated.

The advance of the diaphragms 157, 158 and the power pistons 159, 160 is continued until the atmosphere valve 151a is closed and the atmosphere is not introduced into the variable pressure chambers B, D. As a result, the output depends on the input, that is, the brake pedal depression amount. The output is a predetermined servo ratio. In this state, the atmosphere valve 151a and the vacuum valve 151 of the valve mechanism 151 are
Both b are in the closed state.

On the other hand, in the brake non-operating state, when the controller switches the solenoid valve 152 under the automatic brake operating condition, the atmosphere is introduced into the chamber A ', and this atmosphere further causes the constant pressure passage 163 and the open vacuum valve. It is introduced into the variable pressure chambers B and D through the variable pressure passages 155 and 156, respectively. As a result, the diaphragms 157, 158 and the power pistons 159, 160 move forward and the brake operates, as in the normal braking described above. In this way, when the automatic brake operating condition is satisfied, the solenoid valve 152 is switched by the control signal from the controller, whereby the automatic braking is activated.

[0008]

By the way, in the conventional brake system including the automatic braking device, when the driver depresses the brake pedal to perform the normal braking, the vacuum valve 151b is closed and the constant pressure passage 163 is provided. The variable pressure passage 155 is in a disconnected state. Therefore, even when the driver is stepping on the brake pedal, the automatic brake operation condition is established, and even if the controller switches the solenoid valve 152 to introduce the atmosphere into the chamber A ′ and the constant pressure passage 163, the atmosphere is transformed into the variable passage 155. Will not be introduced to. Therefore, when the driver depresses the brake pedal, the automatic brake cannot be operated even under the automatic brake operating condition.

The present invention has been made in view of the above problems, and an object thereof is to reliably operate the automatic brake even when the normal brake is actuated by stepping on the brake pedal, and at the time of actuating the automatic brake. Even so, it is an object of the present invention to provide a brake system including an automatic braking device that can normally operate a brake reliably.

[0010]

In order to solve the above-mentioned problems, the invention of claim 1 provides a brake operating member, a thrust generator for generating thrust, and a power for operating this thrust generator. A control device for supply control, a master cylinder that generates a master cylinder pressure for normal braking by the brake operation of the brake operating member, and a master cylinder pressure for automatic braking by the thrust of the thrust generator, and each master cylinder pressure. Is supplied to generate a braking force for braking the wheel, and a reservoir for storing brake fluid. The master cylinder includes a housing having an axial hole.
It is disposed in an axial hole of this housing so as to be liquid-tight and slidable, and is moved in the same direction from its non-actuated position by the output by the brake operation of the brake operating member input at one end. A normal brake piston and a fluid-tight and slidable arrangement in the axial hole, and the thrust of the thrust generator input at one end moves it from its non-actuated position in the same direction as this thrust. An automatic brake piston, and a partition formed by the normal brake piston and the automatic brake piston in the housing and communicating with the brake cylinder, and the normal brake master cylinder pressure and the automatic brake master cylinder pressure. And a liquid chamber in which at least one of the Note that at least one of the normal brake piston and the automatic brake piston is provided with a normally-open on-off valve that closes when closed from its respective inoperative position to shut off the reservoir and the liquid chamber. There is. Further, the invention of claim 2 is characterized in that the on-off valve is constituted by a center valve provided on the normal brake piston.

Further, a third aspect of the present invention is a brake operating member, a thrust generator for generating a thrust, a control device for supplying and controlling power for operating the thrust generator, and a brake operation of the brake operating member. Master cylinder pressure for normal braking and the master cylinder pressure for automatic braking by the thrust of the thrust generator, and the master cylinder pressure provided for every two brake systems to supply the master cylinder pressure to brake the wheels. The master cylinder includes a housing having an axial hole and a liquid-tight and sliding contact with the axial hole of the housing. The output by the brake operation of the brake operation member that is arranged at one end and is input to one end The normal braking piston that moves in the same direction as this output from its non-operating position, and the thrust generator that is liquid-tightly and slidably disposed in the axial hole and that is input to one end. Liquid-tight and slidable arrangement in the axial hole between the automatic braking piston that moves from its non-actuated position in the same direction as this thrust due to the thrust, and the normal braking piston and the automatic braking piston The normal brake / automatic brake piston and the brake cylinder of one brake system are defined and formed in the axial hole between the normal brake / automatic brake piston and the automatic brake piston. A first fluid chamber that is in communication with and that generates at least one of the normal brake master cylinder pressure and the automatic brake master cylinder pressure; The normal brake / automatic brake piston and the normal brake piston are sectioned and formed in the axial hole and communicate with the brake cylinder of the other brake system, and the normal brake master cylinder pressure and A second fluid chamber in which at least one of the master cylinder pressures for automatic braking is generated, and the reservoir and the first fluid chamber which are normally opened.
Normally open to communicate with the liquid chamber and close when at least one of the normal brake / automatic brake piston and the automatic brake piston has moved from its inoperative position to shut off the reservoir from the first liquid chamber. Of the first on-off valve, which is normally opened to communicate the reservoir and the second liquid chamber, and at least one of the normal brake / automatic brake piston and the normal brake piston has moved from their respective non-operating positions. It is characterized in that it is provided with a normally open second opening / closing valve that is closed at this time to shut off the reservoir and the second liquid chamber.

Further, the invention of claim 4 is characterized in that the thrust generator is attached to the housing of the master cylinder. Further, the invention of claim 5 is characterized in that the power of the thrust generator is any one of negative pressure, compressed air, hydraulic pressure, power by an electric motor, and electromagnetic force.

[0013]

According to the first aspect of the present invention having the above-mentioned structure, the normal brake is operated by the brake operation of the brake operating member so that the normal brake piston is moved to close the on-off valve and the normal brake is applied to the liquid chamber of the master cylinder. Master cylinder pressure is generated. This normal brake master cylinder pressure is supplied to the brake cylinder to perform normal braking.

When the automatic brake operating condition is satisfied, the control device operates the thrust generator, the thrust generator generates thrust, and the thrust causes the automatic braking piston to move. The movement of the piston for automatic braking closes the on-off valve, and the master cylinder pressure for automatic braking is generated in the liquid chamber of the master cylinder. The master cylinder pressure for automatic braking is supplied to the brake cylinder to perform automatic braking.

Further, when the automatic brake operating condition is satisfied during the normal brake operation by the brake operation of the brake operation member, the thrust of the thrust generator is applied to the automatic brake piston as described above. While the thrust of the thrust generator is smaller than the force generated by the normal brake master cylinder pressure generated in the fluid chamber acting on the automatic brake piston, this automatic brake piston generates the automatic brake master cylinder pressure. Therefore, the brake cylinder pressure is normally kept constant at the master cylinder pressure for braking. When the thrust of the thrust generator exceeds the force generated in the automatic brake piston by the normal brake master cylinder pressure, the automatic brake piston moves to generate the automatic brake master cylinder pressure. This pressure causes the brake cylinder pressure to increase in proportion to the thrust. The pressure of the brake cylinder at this time becomes the same as the brake cylinder pressure when only the automatic brake is operated. In this way, when the automatic brake operates during the normal brake operation, the braking force is strengthened by the automatic brake operation.

Further, when the brake operating member is operated during the automatic brake operation, a force based on the operation of the brake operating member is applied to the normal brake piston as described above. While the force based on the operation of the brake operating member is smaller than the force generated by the automatic brake master cylinder pressure generated in the liquid chamber acting on the normal brake piston,
The normal brake piston does not generate the normal brake master cylinder pressure, and the brake cylinder pressure is kept constant at the automatic brake master cylinder pressure. When the force based on the operation of the brake operating member exceeds the force generated in the normal brake piston by the automatic brake master cylinder pressure, the normal brake piston moves to generate the normal brake master cylinder pressure. This pressure causes the brake cylinder pressure to increase in proportion to the thrust. The pressure of the brake cylinder at this time is the same as the brake cylinder pressure when only the normal brake is operated. In this way, when the normal brake is activated during automatic braking,
The braking force is strengthened by this normal braking operation.

Further, in the third aspect of the invention, in the normal brake, the normal brake piston is moved by the brake operation of the brake operating member to close the second opening / closing valve, and the normal brake / automatic brake piston is moved. Then, the first on-off valve is closed, and the normal brake master cylinder pressure is generated in each of the first and second liquid chambers of the master cylinder. These normal brake master cylinder pressures are supplied to the respective brake cylinders of the two-brake system to perform normal braking.

When the automatic brake operating condition is satisfied, the control unit operates the thrust generator, the thrust generator generates thrust, and the thrust causes the automatic braking piston to move. Then, the movement of the piston for automatic braking closes the first opening / closing valve, and the piston for normal braking and automatic braking moves to close the second opening / closing valve, so that the first and second liquid chambers of the master cylinder are automatically braked. Master cylinder pressure is generated. These automatic brake master cylinder pressures are supplied to the respective brake cylinders of the two-brake system to perform automatic braking.

Further, when the automatic brake operating condition is satisfied during the normal brake operation by the brake operation of the brake operating member, the thrust of the thrust generator is applied to the automatic braking piston as described above. The thrust of the thrust generator is the first
While the normal brake master cylinder pressure generated in the liquid chamber is smaller than the force generated by acting on the automatic brake piston, the automatic brake piston does not generate the automatic brake master cylinder pressure, and the first and second The brake cylinder pressure in the two liquid chambers is normally kept constant at the master cylinder pressure for braking. When the thrust of the thrust generator exceeds the force generated in the automatic brake piston by the normal brake master cylinder pressure, the automatic brake piston moves to generate the automatic brake master cylinder pressure in the first fluid chamber and the normal brake. The piston for automatic braking also moves to generate the master cylinder pressure for automatic braking in the second liquid chamber. Due to these pressures, each brake cylinder pressure increases in proportion to the thrust force. The pressure of the brake cylinder at this time becomes the same as the brake cylinder pressure when only the automatic brake is operated. In this way, when the automatic brake operates during the normal brake operation, the braking force is strengthened by the automatic brake operation.

Further, when the brake operating member is operated during the automatic braking operation, the force based on the operation of the brake operating member is applied to the normal brake piston as described above. While the force based on the operation of the brake operating member is smaller than the force generated by the automatic brake master cylinder pressure generated in the second fluid chamber acting on the normal brake piston, the normal brake piston is used for the normal brake. The master cylinder pressure is not generated, and each brake cylinder pressure is kept constant at the master cylinder pressure for automatic braking. When the force based on the operation of the brake operating member exceeds the force generated in the normal brake piston by the automatic brake master cylinder pressure, the normal brake piston moves to generate the normal brake master cylinder pressure in the second fluid chamber. At the same time, the normal brake / automatic brake piston moves to generate the normal brake master cylinder pressure in the first fluid chamber. Due to these pressures, each brake cylinder pressure increases in proportion to the force based on the operation of the brake operating member. The pressure of the brake cylinder at this time is the same as the brake cylinder pressure when only the normal brake is operated. Thus
When the normal brake operates during automatic brake operation, the normal brake operation increases the braking force.

[0021]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a partial cross-sectional view showing an embodiment of a braking system including an automatic braking device according to the present invention.

As shown in FIG. 1, the brake system of this embodiment includes a negative pressure booster 1, a tandem master cylinder 2, and a thrust generator 3. Negative pressure booster 1
Is a conventionally-known single-type or tandem-type negative pressure booster, and a pedal force of a brake pedal (not shown), which is a brake operating member for normally applying a brake to the input rod 4, is input to the input rod 4. At the same time, the pedal effort of the brake pedal is multiplied by a predetermined servo ratio and output from the output rod 5.

The tandem master cylinder 2 is slidably fitted in each of the holes 7 of the housing 6, and includes a first piston 8 which is a normal brake and automatic brake piston of the present invention and a normal brake piston of the present invention. There is a second
A piston 9 and a third piston 10, which is an automatic braking piston of the present invention, which is also slidably inserted in the hole 7 on the side opposite to the negative pressure booster 1 and operates during automatic braking, are provided. I have it. A first liquid chamber 11 is defined in the hole 7 by the first piston 8 and the third piston 10, and a second liquid chamber 12 is defined by the first piston 8 and the second piston 9. . The first liquid chamber 11 communicates with a wheel cylinder (W / C) (not shown) of the first brake system A through the first output port 13, and the second liquid chamber 12 connects the second output port 14 with the second cylinder. Second through
Brake system B wheel cylinder not shown (W /
It communicates with C).

Further, the first piston 8 and the third piston 10
The first return spring 15 is contracted between the first piston 8 and the second piston 9, and the second return spring 15 is contracted between the first piston 8 and the second piston 9.
The return spring 16 is contracted, and the first, second, and third pistons 8, 9, and 10 are constantly urged by the first and second return springs 15 and 16, respectively. Is in the inoperative position. Further, the second piston 9 is the output rod 5 of the negative pressure booster 1.
The output from the output rod 5 is transmitted to the second piston 9 in cooperation with the.

Ring-shaped first and second cup seals 17 and 18 are attached to the outer circumferences of the left and right ends of the first piston 8, and the first and second cup seals 17 and 18 are provided between the first and second cup seals 17 and 18. A first annular groove 19 is formed on the outer peripheral surface of the one piston 8 and is always in communication with the reservoir 2a. The first cup seal 17 blocks the flow of the brake fluid from the first fluid chamber 11 toward the first annular groove 19 between the inner peripheral surface of the hole 7 of the housing 6 and the outer peripheral surface of the first piston 8. The flow of the brake fluid from the first annular groove 19 toward the first fluid chamber 11 is allowed. Further, the second cup seal 18 is provided between the inner peripheral surface of the hole 7 of the housing 6 and the outer peripheral surface of the first piston 8 so that the second liquid chamber 12
The flow of the brake fluid from the first annular groove 19 to the first annular groove 19 is blocked.

As shown in the enlarged view of FIG. 2, the first piston 8 has a first radial passage hole 20 that opens into a first annular groove 19.
And a first axial passage communicating with the first radial passage hole 20 in the center of the first piston 8 and opening to the front end of the first piston 8, that is, the first liquid chamber 11. A hole 21 is provided. Further, a normally open first center valve 22 is arranged in the first liquid chamber 11, and the first center valve 22 is coaxial with the first axial passage hole 21 and has the first axial passage. First piston 8 around the hole 21
A first valve body 2 that can be seated on a first valve seat 23 formed at the front end
4, a first valve housing 25 that accommodates the first valve body 24, and the first valve body 24 is contracted between the first valve body 24 and the first valve housing 25 so that the first valve body 24 is always in the first valve seat 23. The first valve spring 26 that urges in the direction
The first valve housing 25 slidably extending from the first valve housing 25 toward the third piston 10 in the axial direction.
And a valve rod 27. The first return spring 15 constantly presses the first piston 8 toward the non-actuated position via the valve housing 25 and the third piston 10 always toward the non-actuated position via the first valve retainer 28. It is designed to be pressed. First
The valve rod 27 slidably penetrates through the first valve retainer 28 and has a first large diameter portion 27a formed at the tip thereof. The first large diameter portion 27a is engaged with the first valve retainer 28. By stopping, the tip portion of the first valve rod 27 is prevented from coming out of the first valve retainer 28. Then, when the first and third pistons 8 and 10 are in the inoperative state, the first large diameter portion 27a is locked to the first valve retainer 28, which causes the first valve body 24 to move to the first
Separated from the valve seat 23, the first center valve 22 is open. Therefore, in the brake non-operating state, the first liquid chamber 1
Reference numeral 1 denotes a first passage hole 29 formed in the first valve housing 25, an opened first center valve 22, a first axial passage hole 21, a first radial passage hole 20, and a first annular groove 19. It communicates with the reservoir 2a. Furthermore, the first piston 8
The first flange portion 8a that receives the first cup seal 17 is provided with a first axial through hole 30 that communicates the first liquid chamber 11 and the first annular groove 19.

A normally open second center valve 31 is provided at the front end of the second piston 9 in the second liquid chamber 12, and a second valve retainer abutting against the rear end of the first piston 8 is provided. 32 is provided. These second piston 9, second center valve 31, and second valve retainer 3
2 is the first piston 8 and the first center valve 22 respectively.
And the respective structures of the first valve retainer 28 and the interrelated arrangement structure. Therefore, the first piston 8,
Instead of “first” added to the head of the terms of the components of the first center valve 22 and the first valve retainer 28,
By adding "2" to the head of the terms of the components of the second piston 9, the second center valve 31, and the second valve retainer 32, a detailed description thereof will be omitted. That is, as shown in FIG. 3, the second annular groove 33, the second radial passage hole 34, the second axial passage hole 35, the second valve seat 36, the second
The valve body 37, the second valve housing 38, the second valve spring 39, the second valve rod 40, the second large diameter portion 40a, the second passage hole 41, the second flange portion 9a, and the second through hole 42. Then, in the brake non-operating state, the second liquid chamber 12
Is the second passage hole 4 formed in the second valve housing 38.
1, open second center valve 31, second axial passage hole 3
5, the second radial passage hole 34 and the second annular groove 33 communicate with the reservoir 2a.

Further, annular third and fourth cup seals 43 and 44 are attached to the outer circumferences of the left and right ends of the second piston 9. The third cup seal 43 has the same structure as the first cup seal 17 and is provided in the same direction, and the fourth cup seal 44 is the second cup seal 18.
It has the same structure as and is installed in the opposite direction. Therefore, the third cup seal 43 allows only the flow of the brake fluid from the second annular groove 33 toward the second liquid chamber 12, and the fourth cup seal 44 causes the brake fluid in the second annular groove 33 to be a negative pressure booster. Leakage to the device 1 side is prevented. This second
The piston 9 is prevented from moving toward the negative pressure booster 1 by a stopper ring 45 (shown in FIG. 1).

As shown in FIG. 2, the third piston 10 is provided with a fifth cup seal 48. In the fifth cup seal 48, the brake fluid in the first fluid chamber 11 is applied to the thrust generator 3.
Prevents leakage to the side. Furthermore, the third piston 1
0 is linked to the output rod 46 of the thrust generator 3, and the output of the thrust generator 3 is transmitted to the third piston 10 through the output rod 46 so that the third piston 10 operates.

Further, the thrust generator 3 is electrically connected to an electronic control unit (hereinafter also referred to as ECU) 47,
The operation is controlled by the ECU 47. In that case, the ECU 47 determines, for example, the thrust generator 3
Control the opening and closing of a solenoid on-off valve (not shown) when the power for operating the engine is fluid pressure, and control the drive of this electric motor when the power source for operating the thrust generator 3 is an electric motor, or When the power for operating the thrust generator 3 is an electromagnetic force, the excitation of the electromagnetic solenoid is controlled.
Then, the ECU 47 performs calculation on the basis of, for example, the signals from the wheel speed sensors, the clutch stroke sensor, the clutch switch, the neutral switch, the stop lamp switch, the parking brake switch, and the door switch, and the automatic brake operation based on the calculation result. When it is determined that the condition is satisfied, the thrust generator 3 is controlled to be driven. The automatic brake operating conditions include the conditions for starting a slope, the conditions for holding a braking condition in a signal waiting state and a traffic jam, the conditions for performing traction control, and the conditions for holding a vehicle stopped on a slope. There are conditions, conditions for controlling the inter-vehicle distance during traveling, conditions for suppressing the traveling speed of the vehicle, conditions for preventing forgetting to apply the side brake, and the like.

In the brake system including the automatic brake device of the present embodiment thus configured, the negative pressure booster 1 is operated because the brake pedal is not depressed when neither the illustrated normal brake nor the automatic brake is in operation. Is not output at all and the ECU 47 causes the thrust generator 3 to
Is not driven, the thrust generator 3 outputs nothing. As a result, the first, second and third pistons 8, 9 and 10 are both in the inoperative position shown in the figure, and the first and second center valves 22 and 31 are both open to open the first and second liquid chambers 11 and 11.
Both 12 communicate with the reservoir 2a, and no normal brake pressure or automatic brake pressure is generated in the first and second liquid chambers 11 and 12.

When the brake pedal is depressed to apply the normal brake in this illustrated state, the negative pressure booster 1 boosts the pedal effort with a predetermined servo ratio and outputs it from the output rod 5. 2 Piston 9 advances. By the forward movement of the second piston 9, the second valve body 37 is seated on the second valve seat 36, the second center valve 31 is closed, and the second liquid chamber 12 is shut off from the reservoir 2a. When the second piston 9 is further advanced, the second valve body 37 is also moved forward together, and the brake fluid in the second fluid chamber 12 flows from the second output port 14 to the wheel cylinder (W) (not shown) of the second brake system B.
/ C), the loss stroke of the wheel cylinder is eliminated, and a low normal brake master cylinder pressure (hereinafter, usually referred to as a normal cylinder pressure for the wheel cylinder in the second fluid chamber 12) is not reached. Brake MCY pressure).

This MCY for normal brake in the second liquid chamber 12
The first piston 8 advances due to the pressure and the spring force of the return spring 16. Due to the forward movement of the first piston 8, the first valve body 24 is seated on the first valve seat 23, the first center valve 22 is closed, and the first liquid chamber 11 is shut off from the reservoir 2a. When the first piston 8 is further moved forward, the first valve body 22 is also moved forward together, and the brake fluid in the first fluid chamber 11 is passed from the first output port 13 to the wheel cylinder (W / W) of the first brake system A (not shown). C), the loss stroke of the wheel cylinder is eliminated, and at the same time, a low MCY pressure is generated in the first liquid chamber 11 that is not enough to cause the wheel cylinder to operate the brake.

As the second piston 9 further advances, the first piston 8 also further advances, and the first and second liquid chambers 11 and 12 are moved.
The MCY pressure for normal brake increases. The increased MCY pressure for normal brake is applied to the first and second brake systems A,
Wheel cylinder pressure (hereinafter,
(Also referred to as W / C pressure), the wheel cylinder generates a braking force by this W / C pressure, and the brake is normally applied.

When the brake pedal is released to release the operation of the normal brake, the first and second pistons 8 and 9 and the first and second center valves 22 and 31 are moved to the first and second return springs 15 respectively. , 16 to move toward the non-actuated position. The first large diameter portion 27a of the first valve rod 27 is locked to the first valve retainer 28, and the second large diameter portion 40a of the second valve rod 40 is connected to the second valve retainer 3.
When locked to 2, the first and second valve housings 2
5, 38 and the first and second pistons 8, 9 are retracted with respect to the first and second valve bodies 24, 37, respectively, and the first and second valve bodies 24, 37 are respectively the first and second valves. Zodiac 2
3 and 36, the first and second center valves 22,
31 opens together. As a result, the brake fluid in each wheel cylinder is returned to the reservoir 2a through the first and second fluid chambers 11 and 12, and the first and second brake systems A,
The normal brake of B is released.

When the ECU 47 determines that the automatic brake operating condition is satisfied based on the detection signals from various sensors in the illustrated brake non-operating state, the ECU 47 activates the thrust generator 3 and the thrust generator 3 To occur. This thrust is transmitted to the third piston 10 via the output rod 46, and the third piston 10 and the first valve retainer 28 move toward the first piston 8. By the movement of the first valve retainer 28, the first valve body 24 is seated on the first valve seat 23, the first center valve 22 is closed, and the first liquid chamber 11 is shut off from the reservoir 2a. Due to the further movement of the third piston 10 in the direction of the first piston 8, the brake fluid in the first fluid chamber 11 passes through the first output port 13 to the first brake system A.
Is supplied to the wheel cylinder of the first liquid chamber 11 to eliminate the loss stroke of the wheel cylinder.
In addition, a low MCY pressure for automatic braking is generated, which does not substantially cause the wheel cylinder to operate.

This automatic braking MCY of the first liquid chamber 11
Both the first piston 8 and the second valve retainer 32 move toward the second piston 9 due to the pressure and the spring force of the return spring 15. This second valve retainer 32
The second valve body 37 is seated on the second valve seat 36, the second center valve 31 is closed, and the second liquid chamber 12 is shut off from the reservoir 2a. By the further movement of the first piston 8 toward the second piston 9, the brake fluid in the second fluid chamber 12 is supplied to the wheel cylinder of the second brake system B,
This loss stroke of the wheel cylinder is eliminated, and MCY pressure for automatic braking is generated in the second liquid chamber 12. At this time, the second piston 9 stops the stopper ring 45.
Since the retreat is blocked by, it does not move at all. First
And the further movement of the third pistons 8 and 10 causes the first
And the MCY pressure for automatic braking of the second liquid chambers 11 and 12 rises, and the increased MCY pressure for automatic braking is W / C.
The pressure is supplied to each wheel cylinder, and each wheel cylinder automatically brakes the corresponding wheel.

When the automatic brake operating condition is canceled, E
The CU 47 deactivates the thrust generator 3. Then, the third piston 10 and the first valve retainer 28 move toward the non-actuated position by the first return spring 15, and the first piston 8 and the second valve retainer 3 move.
2 is moved by the second return spring 16 toward the non-actuated position. The first valve retainer 28 is the first valve rod 2
After the first valve retainer 28 is further moved after being locked to the first large diameter portion 27a of No. 7, the first valve body 24 is moved to the first valve seat 23.
The first center valve 22 is opened by separating from the first liquid chamber 1
1 communicates with the reservoir 2a, and further movement of the second valve retainer 32 causes the second valve retainer 32 to move to the second valve retainer 32 after the second valve retainer 32 is locked to the second large diameter portion 40a of the second valve rod 40. The second center valve 31 is opened by separating from the second valve seat 36, and the second liquid chamber 12 communicates with the reservoir 2a. As a result, the brake fluid supplied to the wheel cylinders of each brake system returns to the reservoir 2a in the same manner as in the case of releasing the normal brake described above, and the automatic braking is released.

When the automatic brake operating condition is satisfied during the normal brake operation by depressing the brake pedal, the ECU 47 operates the thrust generator 3 and the thrust generator 3 calculates the thrust F as in the case of the automatic brake described above. 1 and output in the right direction in FIG. At this time, due to the normal brake operation, the normal brake MCY pressure P _{M0 in} the first liquid chamber 11
Is the W / C pressure P _W0 (that is, P _W0 = P _M0 ),
By the W / C pressure P _W0 of the first liquid chamber 11, the thrust generator 3
When the pressure receiving area of the third piston 10 is A, the force f of P _W0 × A is applied to the output rod 46 of FIG.
At the left. Therefore, the ECU 47
After starting the automatic braking operation by, thrust F of thrust generator 3
Is smaller than this force f, the output rod 46 does not move forward.
Therefore, as shown in FIG. 4, during this period, the W / C pressure does not change at all even if the thrust F increases, and the pressure is kept constant at the pressure P _W0 corresponding to the amount of depression of the brake pedal during normal braking. When the thrust F of the thrust generator 3 becomes equal to or greater than the force f, the output rod 46 advances and advances the third piston 10. As a result, as shown in FIG. 4, the MCY pressure for automatic braking of the first and second liquid chambers 11 and 12, that is, each W / C.
The pressure increases in proportion to the increase in the thrust F of the thrust generator 3.
Thus, the automatic brake operates even during the normal brake operation. This automatic braking can increase the braking force. In this state, even if the brake pedal is released and the normal brake is released, the automatic brake is kept activated. Further, the release of the automatic brake at this time is the same as that in the case of the automatic brake described above.

When the normal brake is operated by depressing the brake pedal in order to further increase the braking force during the automatic braking operation, the negative pressure booster 1 applies the force F'to the left in FIG. Output to. At this time, the pressure in the second liquid chamber 12 is W / C due to the automatic brake operation.
The pressure is P _W0 ′, and the W / C pressure P of the second liquid chamber 12 is
_{Due to W0} ', since the pressure receiving area of the second piston 9 is also A, the force _{f'of PW0} ' x A acts on the second piston 9 rearward, that is, rightward in FIG. For this reason,
After starting the normal brake operation by stepping on the brake pedal,
While the force F ′ of the negative pressure booster 1 is smaller than the force f ′, the output rod 5 does not move forward. Therefore, as shown in FIG. 5, during this period, the W / C pressure does not change at all even if the pedal depression force increases, and the W / C pressure is kept constant at the pressure P _W0 'during automatic braking. When the force F ′ of the negative pressure booster 1 becomes equal to or more than the force f ′, the output rod 5 advances and the second piston 9 advances. As a result, as shown in FIG. 5, the normal brake MCY pressures in the first and second liquid chambers 11 and 12, that is, the W / C pressures, increase in proportion to the increase in the pedal effort. Thus, the normal brake operates even during the automatic brake operation. This normal brake can increase the braking force. In this state, even if the automatic brake is released, the normal brake is kept in operation. Further, the release of the normal brake at this time is the same as in the case of the above-mentioned normal brake. Further, even when the propulsion force generator 3 and the third piston 10 fail, normal braking is reliably performed by depressing the brake pedal.

As described above, according to the brake system including the automatic brake device of the present embodiment, the automatic brake can be surely operated if the automatic brake operation condition is satisfied during the normal brake operation. Further, when the brake force due to the brake pressure of the automatic brake is insufficient during the automatic brake operation, the normal brake can be surely operated by depressing the brake pedal 1.

Furthermore, since it is sufficient to simply provide the third piston 10 and the thrust generator 3 on the tandem master cylinder, it is not necessary to prepare a special automatic braking cylinder. Therefore, the types of parts can be reduced and the cost can be reduced.

Further, the propulsion force generator 3 and the third piston 10
Even if the components for automatic braking such as the above are lost, the brake by the normal brake is secured, so the brake system of this embodiment has a fail-safe function.
Although the present invention is applied to the two-brake system in the above-described embodiments, the present invention can be applied to a mere one-brake system in addition to the two-brake system.

[0044]

As is apparent from the above description, according to the brake system including the automatic brake device of the present invention, the automatic brake can be reliably operated during the normal brake operation. You can strengthen your strength. Further, the normal brake can be reliably operated during the automatic brake operation, and the braking force can be increased by the normal brake operation.
Furthermore, even if the components for automatic braking such as the propulsion generator are lost, the normal braking can be secured.
In addition, even if a component for a normal brake such as a brake pedal fails, the brake can be secured by the automatic brake, so the brake system of the present invention has a fail-safe function.

In particular, according to the invention of claim 4, it is not necessary to prepare a special automatic brake cylinder because the automatic brake piston and the thrust generator are simply provided in the master cylinder. Therefore, the types of parts can be reduced and the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of a braking system including an automatic braking device according to the present invention.

FIG. 2 is a partially enlarged sectional view between a third piston and a first piston for automatic braking in the embodiment shown in FIG.

FIG. 3 is a partially enlarged sectional view between a first piston and a second piston in the embodiment shown in FIG.

FIG. 4 is a diagram showing the relationship between the thrust of the thrust generator and the wheel cylinder pressure when the automatic brake operates during the normal brake operation in the embodiment shown in FIG.

5 is a diagram showing a relationship between a pedal effort and a wheel cylinder pressure when a normal brake is activated during automatic braking in the embodiment shown in FIG.

FIG. 6 is a diagram schematically and partially showing a braking system including a conventional automatic braking device.

[Explanation of symbols]

1 ... Negative pressure booster, 2 ... Tandem master cylinder, 2a
... Reservoir, 3 ... Thrust generator, 5 ... Output rod of negative pressure booster, 6 ... Housing, 7 ... Housing hole, 8 ... First piston, 9 ... Second piston, 10 ... Third piston, 11
... first liquid chamber, 12 ... second liquid chamber, 13 ... first output port, 14
… Second output port, 15… First return spring, 16…
2nd return spring, 19 ... 1st annular groove, 20 ... 1st radial passage hole, 21 ... 1st axial passage hole, 22 ... 1st
Center valve, 23 ... First valve seat, 24 ... First valve body, 25
... 1st valve housing, 26 ... 1st valve spring, 27 ... 1st valve rod, 27a ... 1st large diameter part, 28 ...
1st valve retainer, 29 ... 1st passage hole, 31 ... 2nd center valve, 32 ... 2nd valve retainer, 33 ... 2nd annular groove, 34 ... 2nd radial passage hole, 35 ... 2nd axial passage hole , 36 ... Second valve seat, 37 ... Second valve body, 38 ... Second valve housing, 39 ... Second valve spring, 40 ... Second valve rod, 40a ... Second large diameter portion, 41 ... Second passage, Four
5 ... Stopper ring, 46 ... Output rod of thrust generator, 47
... Electronic control unit (ECU)

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[Procedure amendment]

[Submission date] April 21, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction content]

[0010]

In order to solve the above-mentioned problems, the invention of claim 1 provides a brake operating member, a thrust generator for generating thrust, and a power for operating this thrust generator. A control device for supply control, a master cylinder that generates a master cylinder pressure for normal braking by the brake operation of the brake operating member, and a master cylinder pressure for automatic braking by the thrust of the thrust generator, and each master cylinder pressure. Is supplied to generate a braking force for braking the wheels, and a reservoir that stores brake fluid. The master cylinder includes a housing having an axial hole and an axial hole of the housing. The brake operation of the brake operation member is liquid-tightly and slidably disposed in the A normal braking piston that moves in the same direction as the output from its non-actuated position by the output of the thrust force, and the thrust force that is slidably and slidably disposed in the axial hole and is input to one end. Brake piston that moves in the same direction as this thrust from its non-actuated position by the thrust of the device, and is formed in the housing by the normal brake piston and the automatic brake piston, and communicates with the brake cylinder. And a liquid chamber in which at least one of the normal brake master cylinder pressure and the automatic brake master cylinder pressure is generated, and which is normally opened to communicate the reservoir and the liquid chamber, and the normal brake piston and the automatic brake Close when at least one of the braking pistons is moved from its inoperative position. It is characterized in that it comprises a normally open on-off valve to cut off the serial reservoir and said fluid chamber. In the invention of claim 2, the on-off valve is
It is characterized by being constituted by a center valve provided in the normal brake piston.

Claims (5)

[Claims] 1. A brake operating member, a thrust generator for generating thrust, a control device for supplying and controlling power for operating the thrust generator, and a master cylinder for normal braking by brake operation of the brake operating member. A master cylinder that generates pressure and a master cylinder pressure for automatic braking by the thrust of the thrust generator, and a brake cylinder that is supplied with each master cylinder pressure to generate a braking force for braking the wheel, The master cylinder is composed of a reservoir for storing brake fluid, the master cylinder is provided with a housing having an axial hole, and is fluid-tightly and slidably disposed in the axial hole of the housing and is inputted to one end thereof. The output from the brake operation of the brake operation member moves in the same direction as this output from the non-actuated position. A normal brake piston and a fluid-tight and slidable arrangement in the axial hole, and the thrust of the thrust generator input at one end moves it from its non-actuated position in the same direction as this thrust. An automatic brake piston, and a partition formed by the normal brake piston and the automatic brake piston in the housing and communicating with the brake cylinder, and the normal brake master cylinder pressure and the automatic brake master cylinder pressure. When at least one of the normal brake piston and the automatic brake piston moves from their respective non-actuated positions, the liquid chamber in which at least one of A normally open on-off valve that closes and shuts off the reservoir and the liquid chamber is provided. Brake system with an automatic braking system according to claim. 2. The brake system with an automatic brake device according to claim 1, wherein the on-off valve is constituted by a center valve provided on the piston for normal braking. 3. A brake operating member, a thrust generator for generating thrust, a control device for supplying and controlling power for operating the thrust generator, and a master cylinder for normal brake by brake operation of the brake operating member. A master cylinder that generates pressure and a master cylinder pressure for automatic braking by the thrust of the thrust generator, and a braking force that is provided for every two brake systems and is supplied with each master cylinder pressure to brake the wheels. And a reservoir for storing brake fluid. The master cylinder is provided with a housing having an axial hole and a liquid-tight and slidable arrangement in the axial hole of the housing. The brake operating member outputs at one end and the brake operating member outputs it from its non-operating position. A normal brake piston that moves in the same direction as this output, and its non-actuated position due to the thrust of the thrust generator that is disposed in the axial hole in a liquid-tight and slidable manner and that is input to one end. To the automatic braking piston that moves in the same direction as this thrust, and the normal braking and fluid-liquid slidably disposed in the axial hole between the normal braking piston and the automatic braking piston. An automatic brake piston, a partition formed in the axial hole between the normal brake / automatic brake piston and the automatic brake piston, and communicating with the brake cylinder of one brake system and the normal brake Fluid chamber for generating at least one of the master cylinder pressure for automatic braking and the master cylinder pressure for automatic braking, and A master cylinder pressure for normal braking and a master cylinder for automatic braking, which is defined and formed in the axial hole between the brake piston and the normal brake piston and communicates with the brake cylinder of the other brake system. At least one of the normal brake / automatic brake piston and the automatic brake piston and the second liquid chamber in which at least one of the pressures is generated and the reservoir and the first liquid chamber that are normally opened to communicate with each other Closed when moving from the non-actuated position of the reservoir and the first
At least one of the normally open first on-off valve that shuts off the liquid chamber and the normally open valve that communicates with the reservoir and the second liquid chamber and that has the normal brake / automatic brake piston and the normal brake piston A brake system provided with an automatic brake device, comprising: a normally open second on-off valve that closes when moving from each non-operating position to shut off the reservoir and the second liquid chamber. 4. A brake system including an automatic brake device according to claim 1, wherein the thrust generator is attached to the housing of the master cylinder. 5. The power of the thrust generator is any one of negative pressure, compressed air, hydraulic pressure, power generated by an electric motor, and electromagnetic force, according to any one of claims 1 to 4. Brake system with automatic braking device.