JPH11245797A - Brake hydraulic pressure control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a brake hydraulic pressure control device that is equipped with an electric braking function, and besides, a brake piping system is formed into three systems consisting of both lateral front parts and one rear part. SOLUTION: This hydraulic pressure control device is equipped with a master cylinder 2, a control valve 3, and hydraulic pressure transmission devices 4 and 5 respectively, and the hydraulic pressure transmission devices 4 and 5 are set up each in an independent piping system out of both lateral front-wheel systems, while the control valve transfers a passage in the control valve by hydraulic pressure out of a pressure source 11 being outputted from a solenoid proportional control valve 70 to be operated by an electronic control device, therefore the hydraulic pressure intensified is made so as to be outputted, and the output hydraulic pressure out of the control valve is made directly feedable to a rear wheel cylinder 8, while a piston of the front-wheel hydraulic pressure transmission device is operated, and the hydraulic pressure produced in the front-wheel hydraulic pressure transmission device is fed to two corresponding lateral front wheel cylinders 6 and 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake fluid pressure control device for a vehicle, and more particularly, to a brake fluid pressure control device for a front hydraulic pressure system, which comprises three front, left, right and rear brake piping systems. If one side fails,
The present invention relates to a highly safe brake fluid pressure control device having an electrically controlled brake (so-called brake-by-wire) function, in addition to a brake force that can be reliably obtained by the other front system and rear system.

[0002]

2. Description of the Related Art Conventionally, there has been known a brake fluid pressure control device which performs a boosting function by switching a flow path by a pressure generated in a master cylinder and transmitting a fluid pressure from a fluid pressure source to a fluid pressure transmitting device. Yes (Japanese Patent Publication No. 61-53265)
issue).

[0003] The hydraulic brake system described in the above publication will be briefly described with reference to FIG. 4. In this system, when a driver operates a brake pedal 301, a hydraulic pressure is generated in a master cylinder 302. Reaches the modulator cylinder 303 through the branch pipes 304a and 306a, and the pistons 307 and 308
And displaces the pistons 307, 308 to the left, and by the conical end 310 of the shutoff valve 309,
The hole 311 of the piston 308 is closed and the flow path 312 is closed.
Is closed, and a servo hydraulic pressure is generated in the chamber 313.

The hydraulic pressure generated in the chamber 313 causes the shut-off valve 309 to be displaced against the force of the return spring 314, and as a result, pressurized hydraulic oil flows into the distribution chamber 315, from which the front and rear wheels are further moved. It flows into the respective chambers 317 of both servo cylinders via the system line 316. The pressure generated in the chamber 317 displaces each servo piston 318, and accordingly the stem 319 is displaced to the right in the drawing, so that the end flange 320 of each stem moves each auxiliary piston 321.
To close the hole 322 of each auxiliary piston 321. In this way, the thrust of the servo piston 318 causes each auxiliary piston 321 to move, pressurizing the hydraulic oil in the chamber 323, and
a, 306a, the hydraulic pressure present in the respective chamber 323 supplied via the auxiliary piston 32
The brake pedal 1 receives the servo force to actuate the brakes of the front wheels and the rear wheels, so that the depression force of the brake pedal 301 can be reduced.

[0005]

However, the brake fluid pressure control device described in the above publication has two brake piping systems divided into a front wheel system and a rear wheel system. If a failure occurs in the system, for example, the upper brake system in the figure (here, the front system), the front system does not apply the braking force, and the braking is performed only by the left and right rear wheels. Become. That is, in the above-described brake fluid pressure control device, 2
If a failure occurs in one of the pipes of the system, both left and right wheels of the system will not be able to apply braking force, which is a problem in safety. Further, in the above-described brake fluid pressure control device, the brake system is made up of two systems of front and rear wheels, and a booster including a servo piston 318 and a stem 319 is arranged in each brake system. This is disadvantageous in increasing the size of the device and reducing costs. Furthermore, in the recent trend of electronic control of vehicles, the above-mentioned device does not have a function corresponding to an electrically controlled brake (brake-by-wire), which is expected to be developed in the future, and furthermore, it is intended for persons with disabilities. Is difficult to apply as a brake device.

Accordingly, the present invention provides a control valve 3 for outputting the hydraulic pressure of a pressure source (eg, an accumulator) which is increased in proportion to the hydraulic pressure generated in the master cylinder 2.
And a pair of left and right front wheel hydraulic pressure transmitting devices 4 and 5 capable of generating a hydraulic pressure by an output hydraulic pressure from the control valve are respectively arranged in independent piping systems of the left and right front wheel systems. In the wheel system, the output hydraulic pressure from the control valve is directly supplied to the rear wheel cylinder to operate the brake, and in the front wheel system, the output hydraulic pressure from the control valve is applied to the left and right front wheel hydraulic pressure transmitting devices. An object of the present invention is to solve the above-described problems by enabling the hydraulic pressure generated by the left and right front wheel hydraulic pressure transmitting devices to be supplied to the corresponding front wheel cylinders. Also, the present invention provides an electromagnetic proportional control valve disposed between a control valve and an accumulator, and the electromagnetic proportional control valve is actuated by a command from an operation unit such as a manually operated brake lever or a hand switch. The flow path in the control valve is switched by the hydraulic pressure from the accumulator output from the control valve, so that the hydraulic pressure of the accumulator increased in proportion to the output pressure from the electromagnetic proportional control valve can be output from the control valve. This enables application to vehicles for the physically handicapped. Further, by adopting a configuration in which the control valve (power booster) is separated from the master cylinder, vehicle mountability is improved. According to the present invention, even if a failure occurs in one of the front wheel systems, the braking force of the front wheel on the other side is maintained, so that it is possible to prevent a situation in which the braking force is insufficient, and it is also possible to prevent the fluid of the rear wheel system from being insufficient. By omitting the pressure transmitting device, it is possible to prevent the device from increasing in size and cost. Further, it is possible to obtain a brake fluid pressure control device that can be easily applied to a vehicle for a physically handicapped person.

[0007]

Therefore, the technical solution adopted by the present invention is to provide a control valve for outputting a hydraulic pressure of a pressure source increased in proportion to a hydraulic pressure generated in a master cylinder; A pair of hydraulic pressure transmitting devices that generate a hydraulic pressure by operating a piston by an output hydraulic pressure from a control valve, wherein the pair of hydraulic pressure transmitting devices are respectively disposed in independent piping systems of left and right front wheel systems, The valve switches the flow path in the control valve by the hydraulic pressure from the pressure source output from the electromagnetic proportional control valve operated by the command signal from the electronic control unit, and increases the pressure in proportion to the output pressure from the electromagnetic proportional control valve The output hydraulic pressure of the pressure source can be output, and the output hydraulic pressure from the control valve can be directly supplied to the rear wheel cylinder, and the pair of the A brake hydraulic pressure control device characterized in that a piston of a wheel hydraulic pressure transmission device is actuated to supply hydraulic pressure generated by the front wheel hydraulic pressure transmission device to corresponding left and right front wheel cylinders. .

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an overall configuration diagram of the brake fluid pressure control device, and FIG. 2 is a control valve used in the brake fluid pressure control device. FIG. 3 is an enlarged sectional view of a hydraulic pressure transmission device.
Hereinafter, after describing the overall configuration of the brake fluid pressure control device, each component of the control valve, the electromagnetic proportional control valve, and the fluid pressure transmission device will be described in detail. For convenience of explanation, the system that exerts braking force by stepping on the brake pedal is referred to as a hydraulic brake system, and the system that exerts braking force in response to a command signal from an electronic control unit is referred to as an electrically controlled brake system. explain.

In FIG. 1, 1 is a brake pedal, B is a brake stroke sensor, 2 is a tandem master cylinder, 3 is a control valve, 4 is a left front wheel hydraulic pressure transmitting device, 5 is a right front wheel hydraulic pressure transmitting device, and 6 is a right front wheel hydraulic pressure transmitting device. Left front wheel cylinder, 7 is right front wheel cylinder, 8 is left and right rear wheel cylinders, 9 is a hold valve corresponding to each wheel, 10 is a decay valve corresponding to each wheel, 11
Is an accumulator as a pressure source, 12 is a pressure sensor,
13 is a hydraulic pump, 14 is a relief valve, 15 is a normally open first switching valve, 16 is a normally closed second switching valve, 17
Is a flow path switching valve arranged in an independent piping system for the left and right front wheels, 18 is a reservoir, S is a wheel speed sensor, and these are communicated by a flow path as shown in the figure. In the present embodiment, the control valve 3 and the left and right front wheel hydraulic pressure transmitting devices 4 and 5 are integrally assembled as one control unit M. In this unit M, an electromagnetic proportional control valve for an electrically controlled brake system is provided. Is arranged. The pressure of the accumulator is constantly monitored by the pressure sensor 12, and the hydraulic pump 1 is controlled so that the pressure of the accumulator 11 is within a predetermined range.
3 is controlled.

Each of the sensors S and B and each switching valve 1
5, 16, 17, hold valve 9, decay valve 1
The hydraulic pump 13, a hand switch, a hand lever, and the like (not shown) are connected to an electronic control unit (ECU) in the figure. The valves, hydraulic pumps, and the like are opened / closed and driven by commands from an electronic control unit according to the operating state (described later) of a hydraulic brake system or an electrically controlled brake system to operate the brake. In operation, the second switching valve 16 has a function of opening and closing little by little by a signal from the electronic control unit to adjust the hydraulic pressure supplied from the accumulator.

In the hydraulic brake system, when the brake pedal 1 is operated and a fluid pressure (hydraulic pressure) is generated in the tandem master cylinder 2, the control valve 3 (details will be described later) is actuated by the fluid pressure, and the control is performed. A fluid pressure proportional to the fluid pressure of the master cylinder is output from the valve 3 and transmitted directly to the left and right rear wheel brake cylinders from the first output port 3c of the control valve 3, and a flow path to be described later. And transmitted to the left and right front wheel cylinders 6 and 7 through the flow path switching valve 17 from the output ports 4a and 5a of the hydraulic pressure transmission devices 4 and 5 via the flow passage switching valve 17. Work.

If the wheels are likely to be locked during the braking operation, a signal from the wheel speed sensor S causes the electronic control unit (ECU) to switch the flow path switching valve 17 so that the hydraulic pressure transmission devices 4 and 5 The output ports 4a, 5a are cut off from the front wheel cylinders 6, 7, and the left and right front wheel cylinders 6, 7 communicate with the first output port 3c. At this time, the control valve 3, the left and right hydraulic pressure transmitting devices 4, 5
Is maintained in the state at the time of braking. When the hold valve 9 is closed in this state, the wheel cylinder pressure is maintained,
When the decay valve 10 is opened with the hold valve 9 closed, the pressure fluid in the wheel cylinders 6 to 8 returns to the reservoir 11 to reduce the wheel cylinder pressure. Also,
When it is necessary to re-pressurize, when the decay valve 10 is closed and the hold valve 9 is opened, the hydraulic pressure of the accumulator 11 becomes third through both the front and rear wheel systems via the control valve 3.
Input port 3d → flow path in control valve 3 → first
The air is supplied to each of the front and rear wheel cylinders via the output port 3c and re-pressurized. When the hydraulic pressure of the accumulator 11 becomes lower than a predetermined pressure during the antilock control, the flow path switching valve 17 is activated by a command from the electronic control unit as shown in FIG.
Return to normal braking state.

In this way, the anti-lock control is executed while maintaining the hydraulic pressure in the wheel cylinders 6, 7, 8 as necessary through the control valve 3, and reducing and increasing the pressure. When the hydraulic pressure in the accumulator decreases as well as during the antilock control, the hydraulic pump 13
It is activated by a signal from the second unit 2 and can accumulate a predetermined pressure in the accumulator 13 as needed. In addition,
At the time of the pressure reduction during the antilock control, the hydraulic pressure from the wheel cylinder is directly returned to the reservoir from the decay valve 10, so in the present embodiment, the brake fluid is supplied to the master cylinder during the antilock control as in the related art. It is possible to eliminate the need for a hydraulic pump for recirculating the fluid, and to reduce the size and weight of the device.

Further, when slippage occurs in the driving wheels when the vehicle starts, or when the brake is automatically applied by shortening the inter-vehicle distance, furthermore, in order to secure the stability of the vehicle body during turning, yaw moment control or the like is used. When executing the automatic brake control, the first switching valve 15 is closed, the second switching valve 16 is opened by a command signal from the electronic control unit ECU, and the hydraulic pressure is directly supplied from the accumulator 11 to the wheel cylinder 8 of the rear wheel. The hydraulic pressure of the accumulator 11 is further supplied to the front and rear hydraulic pressure transmitting devices 4 and 5 via the control valve 3, and the hydraulic pressure generated in the output chambers of the hydraulic pressure transmitting devices 4 and 5 is supplied to the output ports 4 a and 4. 5a → Supply to the left and right front wheels via the flow path switching valve 17, and apply an appropriate braking force to the left and right front wheels. The adjustment of the hydraulic pressure at this time is performed by opening and closing the hold valve 9 and the decay valve 10 as in the case of the antilock control.

In the electrically controlled brake system, a hand lever, a hand switch, a brake stroke sensor,
The control unit M is controlled by a command signal of an electronic control unit for evaluating electric signals from a wheel speed sensor, an inter-vehicle distance sensor, etc.
When the electromagnetic proportional control valve inside is operated, the hydraulic pressure from the accumulator acts on the control valve via the electromagnetic proportional control valve, switches the flow path in the control valve, and the hydraulic pressure acting on the control valve in the control valve The hydraulic pressure of the accumulator, which has been increased in proportion to the pressure, is output from the first output port 3c of the control valve 3, and this output is directly transmitted to the left and right rear wheel brake cylinders and to the left and right front wheel hydraulic pressure transmitting devices 4, 5. Further, the brake fluid is supplied from the output ports 4a and 5a of the hydraulic pressure transmitting devices 4 and 5 to the left and right front wheel cylinders 6 and 7 through the flow path switching valve 17 to apply a braking force. In the case of an electrically controlled brake system, the hydraulic pressure output from the control valve acts on each wheel cylinder similarly to the hydraulic brake system. In the same manner as in the hydraulic brake system, the valves 9 and 10 are operated to maintain, reduce, and increase the braking force.

Further, when slippage occurs in the driving wheels when the vehicle starts, or when the brake is automatically applied by shortening the inter-vehicle distance, furthermore, in order to ensure the stability of the vehicle body during turning, yaw moment control or the like is used. When executing the automatic brake control, when the electromagnetic proportional control valve in the control unit M is operated via the electronic control device by a signal from the wheel speed sensor S or the inter-vehicle distance sensor, the hydraulic pressure from the accumulator becomes electromagnetic proportional. It acts on the control valve via the control valve, switches the flow path in the control valve, and in the control valve, the hydraulic pressure of the accumulator increased in proportion to the hydraulic pressure acting on the control valve is used as the first control valve 3 The output from the output port 3c is transmitted directly to the left and right rear wheel brake cylinders. Wheel hydraulic pressure transmitter transmitted to 4,5, and the output port 4a of the liquid pressure transmission device 4, 5, the left and right front wheel cylinder 6 via the flow path switching valve 17 from the 5a,
7 to apply the braking force to eliminate the phenomenon such as slip. In this way, the brake force can be exerted using the hydraulic pressure from the accumulator even during automatic braking or the like. In the control of the brake hydraulic pressure, each valve is operated in the same manner as in the hydraulic brake system, and the brake force can be maintained, reduced, and increased.

As described above, the operation of the automatic brake operation basically differs depending on whether it is a hydraulic brake system or an electrically controlled brake system, as described later. That is, when the hydraulic brake system is selected, the automatic braking is performed by opening and closing the first switching valve 15 and the second switching valve 16, and when the electric control type brake system is selected, the brake operation is performed by operating the electromagnetic proportional control valve 70. . However, these may be limited to one mode depending on the contents of the program of the microcomputer in the electronic control unit, or if a failure occurs in either system, the braking mode of the other system is automatically set. You may make it possible to change to.

Hereinafter, details of main components constituting the present hydraulic pressure control device will be described. [Control Valve 3] In FIG. 2, the control valve 3 has a pilot piston 20, a diaphragm piston 21, and a spool piston 22 in the arrangement shown in the main body, and each piston 20 to 22 is formed in the main body. The first cylinder 24, the second cylinder 25, and the third cylinder 26 formed on the port member 27 are slidably disposed. The port member 27 is fixed to the main body by appropriate means. The pressure receiving areas A5 and A4 of the diaphragm piston 21 and the spool piston 22 are A5
> A4 (see FIG. 3).

The pilot piston 20 is a first cylinder 2
4 and is formed as a stepped piston composed of a large-diameter portion 20a and a small-diameter portion 20b.
The first input liquid chamber 28 and the second input liquid chamber 29 in the cylinder 24
And an atmosphere chamber 30. The first input liquid chamber 28 of the control valve 3 is connected to the second hydraulic pressure generation chamber 2b of the tandem master cylinder 2 via the first input port 3a, and the left front wheel hydraulic pressure transmission device 4 (described later) via the flow path 31. The second input liquid chamber 2 is connected to the input liquid chamber 62
9 is connected to the second input port 3 b and the input liquid chamber 62 of the right front wheel hydraulic pressure transmitting device 5 through the flow path 33 and the normally open third switching valve 73, and further to the electromagnetic proportional control valve 70 through the flow path 33.
(Described later). The second input port 3b of the control valve 3 communicates with the first hydraulic pressure generation chamber 2a of the tandem master cylinder 2, and the atmosphere chamber 30 in the control valve 3 communicates with the atmosphere. The second input liquid chamber 29 is connected in parallel to the above-described normally-open third switching valve 73.
A check valve 75 is disposed to prohibit the flow from the inlet to the input liquid chamber 62. The pilot piston 20 is connected to the first spring 3 disposed in the second input liquid chamber 29.
4 is normally urged rightward in the figure and is in contact with the main body wall surface.

A diaphragm piston 21 disposed opposite to the pilot piston 20 is slidably provided in a second cylinder 25 formed in the main body, and a diaphragm 36 is provided on an end face. The second input liquid chamber is formed by the diaphragm 36. 29 and liquid-tight. On the left end face of the diaphragm piston 21 in the figure, an engagement projection 38 is formed which is in contact with the spool piston 22, and a liquid chamber 37 defined by the left end face of the diaphragm piston 21 in the figure.
Is connected to the reservoir 18 via the second output port 3e → the first switching valve 15. The diaphragm piston 21 is moved by the second spring 35 to the spool piston 22.
And the engaging projection 38 is pushed toward the spool piston 2.
It is in contact with 2.

The engagement projection 38 of the diaphragm piston 21
The spool piston 22 in contact with the spool piston 22 is slidably disposed in the third cylinder 26 in the port member 27 fixed to the main body.
This flow path 42 communicates with a groove 41 formed on the outer periphery of the spool piston 22. On the other hand, port member 2
7, a first passage 39 and a second passage 40 are formed.
The second passage 40 is connected to the electromagnetic proportional control valve 7 through a passage 74.
0 is always in communication with the input port 72. The groove 41 of the spool piston 22 communicates with the second output port 3e via the first passage 39 of the port member 27 when not in operation, and further with the reservoir 18 via the first switching valve 15 when the spool piston 22 is not in operation. Moves leftward from the illustrated state (that is, during operation), the groove 41 is connected to the accumulator 11 via the second passage 40 and the third input port 3d of the port member 27 and to the input port 72 of the electromagnetic proportional control valve 70. Communicate. The width L of the groove 41 is set to be slightly smaller than the distance between the first passage 39 and the second passage 40 formed in the port member 27.
The flow path 42 in the center of the first passage 39 on the port member 27 side
When the spool 41 is moved from the state communicating with the second passage 40 to the state communicating with the second passage 40 on the port member 27 side, a slight time lag occurs. The spool piston 22 is positioned by the wall surface of the main body at the right end face in the figure by the urging force of the return spring 43. The return spring 4 described above
The load relationship between the third spring 35 and the second spring 35 is as follows: return spring 43> second spring 35.

The flow path 42 at the center of the spool piston 22 is connected to the accumulator 11 via the boost chamber 46 → the first output port 3c → the second switching valve 16 and to the boost chamber 4
Numeral 6 is connected to the left and right front wheel side hold valves 9 via the flow path switching valve 17 and directly to the rear wheel system hold valve 9. In addition, it communicates with the pressure introduction chamber 63 of the left and right front wheel hydraulic pressure transmission devices 4 and 5 described later via the flow path 45. For this reason, in the control valve 3, the boost chamber 46 holds the spool piston 2 when not operating.
Flow path 42 at the center of 2 → groove 41 of spool piston → first passage 39 on port member 27 side → second output port 3 e →
Since the boost chamber 46 is in communication with the accumulator by the normally open second switching valve 16, the boost chamber 46 is in a non-pressure state. ing. Therefore, no hydraulic pressure is generated in the wheel cylinders 8 of the rear wheels, and no hydraulic pressure acts on the pressure introduction chambers 63 of the front wheel hydraulic pressure transmitting devices 4 and 5, so that hydraulic pressure is also applied to the front wheel cylinders 6 and 7. Has not occurred. The control valve 3 is configured such that the hydraulic pressure from the master cylinder simultaneously acts on both end surfaces of the pilot piston 20. Either the first hydraulic pressure generating chamber 2a or the second hydraulic pressure generating chamber 2b is used. A similar braking action can be achieved even if the vehicle fails.

[Electromagnetic proportional control valve 70] Electromagnetic proportional control valve 7
The electronic control unit evaluates a signal from a hand lever or a hand switch that outputs an output signal proportional to an operation force (not shown), a wheel speed sensor, and a headway distance sensor, and performs electromagnetic proportional control according to a command signal from the electronic control unit. The valve 70 is
For example, the hydraulic pressure according to the operation amount of the hand lever can be supplied from the accumulator to the control valve. A known valve can be used as the electromagnetic proportional control valve. The flow path 76 connects the electromagnetic proportional control valve 70 to the reservoir.

[Hydraulic pressure transmitting devices 4 and 5] Since each of the hydraulic pressure transmitting devices 4 and 5 for the left and right front wheels has the same structure and function, the hydraulic pressure transmitting device 4 on the left front wheel side is illustrated here. This will be described with reference to FIG. In FIG. 2, the hydraulic pressure transmitting device 4 includes a first piston 51, a second piston 52, and a third piston 53.
Are slidably provided in the main body in the arrangement shown in the figure, and a small-diameter portion 51a of the first piston 51 is slidably fitted to the right central portion of the second piston 52 in the drawing. The first piston 51 defines an input liquid chamber 62 in the main body, a liquid chamber 58 is formed between the first piston 51 and the second piston 52, and a third piston 53 is formed on the outer periphery of the second piston 52.
Are fitted as shown in the drawing, and an output chamber 64 is defined on the left side of the second piston 52 and the third piston 53 in the drawing, and a liquid chamber 65 is defined between the second piston 52 and the third piston 53. doing. This liquid chamber 65 is the second piston 52
A first piston 51 and a second piston 52 via a passage 57 formed therein and a passage 58a formed in the first piston.
And a liquid chamber 58 formed between the two. Further, the second piston 52 and the third piston 53 are arranged to face each other with a gap S therebetween. Further, a pressure introducing chamber 63 is defined between the second piston 52 and the main body, and the pressure introducing chamber 63 is connected to the boost chamber 46 of the control valve 3 through the flow path 4.
As shown in FIG.

The input fluid chamber 62 of the left front wheel hydraulic pressure transmitting device 4 is
It communicates with the first input liquid chamber 28 of the control valve 3 (which is always in communication with the second hydraulic pressure generation chamber 2b of the master cylinder).
It communicates with the output chamber 64 in the hydraulic pressure transmitting device via 9a. The poppet valve 59 is urged by a poppet spring 60 so that a projection 59b thereof comes into contact with the first piston 51. When the poppet valve 59 is not activated, the poppet valve 59 opens a passage 59a as shown to open the input liquid chamber 62 and the output chamber 64. And communicates. When the first piston 51 moves to the left in the figure, the poppet valve 59 moves the poppet spring 6.
The urging force of 0 moves to the left in the figure, and the valve body 61 blocks the communication between the input liquid chamber 62 and the output chamber 64. The input chamber 62 of the right front wheel hydraulic pressure transmitting device 5 is connected to the second input liquid chamber 29 of the control valve 3 and the output port 71 of the electromagnetic proportional control valve 70 via the flow path 33 and the normally open third switching valve 73. And the first hydraulic pressure generating chamber 2a of the master cylinder 2 through the second input port 3b.

A spring 55 is disposed in the output chamber 64. A spring holder 54, a second piston 52, and a first piston 51, which will be described later, are urged rightward in the drawing by the urging force F of the spring 55. The first piston 51 is in contact with the main body. The second piston 5
A spring holder 54 is provided between the second and third pistons 53.
A spring 56 is arranged via the spring 55, and is configured to exert an urging force f against the urging force F of the spring 55. The third piston 53 is configured such that the spring holder 54 is pushed rightward in FIG. Therefore, the spring 56 comes into contact with a stopper 66 formed on the main body side by the urging force of the spring 56.

The load relationship between the poppet spring 60 and the springs 55 and 56 is as follows: poppet spring 60 + spring 56 <spring 55. The pressure receiving area of the first piston 51 is A
1. The annular pressure receiving area of the second piston 52 is A2, and the sum of the pressure receiving area of the third piston 53 and the pressure receiving area of the left end face of the second piston 52 in the drawing is A3, and the springs 55 and 56 described above are formed. F, f, the hydraulic pressure of the master cylinder is Pm, the hydraulic pressure of the hydraulic pressure introducing chamber 63 acting on the pressure receiving area A2 is Pr, and the output chamber 6 acting on the pressure receiving area A3.
Assuming that the hydraulic pressure on the fourth side (output hydraulic pressure) is Pf, the balance equation after the passage 59a is closed has the following relationship: f + PmA1 + PrA2 = PfA3 + F. From this equation, Pr and Pf are appropriate. The pressure receiving area and the spring force are set so as to have a relationship. The output chambers 64 of the left and right front wheel hydraulic pressure transmitting devices 4 and 5 are ports 4a and 5
Each is connected to the flow path switching valve 17 via a. When the hydraulic pressure transmitting device 4 is not operated, the poppet valve 59
Maintain the illustrated state and open the passage 59a.

[Wheel Cylinder, Decay Valve and Hold Valve] The control valve device including the decay valve 9 and the hold valve 10 has the same structure as the conventional recirculation type antilock control device. The electronic control unit (E
CU). The hold valve 9 and the decay valve 10 are opened and closed not only during the antilock control but also during the automatic braking such as the traction control and the yaw moment control by the command from the electronic control device as described in the operation section described later. And adjust the brake pressure. In addition, the electronic control unit can take in information from other sensors and the like as needed in addition to the above-mentioned sensors, and can also control opening and closing of each valve.

The operation of the brake fluid pressure control device configured as described above will be described. [Non-operation] When the brake pedal 1 is released and no fluid pressure is generated in the tandem master cylinder 2, no fluid pressure is generated in the first and second input fluid chambers 28 and 29 in the control valve 3. Valve 3 does not work,
The state of FIG. 2 is maintained. As a result, the pressure fluid from the accumulator 11 is cut off by the spool piston 22 in the control valve 3, and the input liquid chamber 62 and the pressure introduction chamber 63 of the hydraulic pressure transmission device are pressureless, so that the pressure is not applied to the wheel cylinder. Does not generate hydraulic pressure.

[During Operation of Hydraulic Brake System] When the driver steps on the brake pedal 1 and generates hydraulic pressure in the tandem master cylinder 2, the first input liquid chamber 28 and the second input liquid chamber 29 in the control valve 3 are provided. Although the hydraulic pressure of
Since the hydraulic pressures at both ends of the pilot piston 20 are equal, the pilot piston 20 does not move. The electromagnetic proportional control valve 70 does not generate pressure at its output port 71 when not operating. The hydraulic pressure in the first hydraulic pressure generation chamber 2a of the master cylinder 2 flows into the second input liquid chamber 29 via the second input port 3b of the control valve 3, the opened third switching valve 73 or the check valve 75, and is controlled. Valve 3
The input liquid chamber 62 of the right front wheel side hydraulic pressure transmission device 5 acts on the diaphragm piston 21 in the
Is transmitted to The second piston 52 in the right front wheel hydraulic pressure transmission device 5 moves between the gaps S by the hydraulic pressure introduced into the input liquid chamber 62. During the movement between the gaps S, the poppet valve 59 closes the passage 59 a and cuts off the communication with the output chamber 64.

On the other hand, the second tandem master cylinder 2
The hydraulic pressure of the hydraulic pressure generating chamber 2 b is supplied to the left front wheel hydraulic pressure transmitting device 4 via the first input port 3 a of the control valve 3 and the flow path 31.
And the first input liquid chamber 28 of the control valve 3. The second piston 52 in the hydraulic pressure transmitting device 4 moves between the gaps S on the left side in the figure due to the hydraulic pressure introduced into the input liquid chamber 62. During the movement between the gaps S, the poppet valve 59 closes the passage 59 a and the output chamber 64.
Cuts off communication with the When hydraulic pressure acts on the diaphragm piston 21 in the control valve 3, the piston 21 moves to the left in FIG. 2, and the spool piston 22 also moves to the left in the figure. At this time, since the diaphragm piston 21 moves while deforming the diaphragm 36, the sliding resistance of the diaphragm piston 21 can be reduced and the responsiveness is improved as compared with the conventional case where a seal is arranged around the piston. .

Further movement of the spool piston 22 causes the central flow passage 42 in the spool piston 22 to
→ The second passage 40 of the port member 27 → The third input port 3d
The pressure fluid in the accumulator 11 is communicated with the accumulator 11 through the central passage 42 → the boost chamber 46 →
The flow path 45 is introduced into the pressure introduction chamber 63 of the front wheel hydraulic pressure transmitting devices 4 and 5, and the second piston 52 in the hydraulic pressure transmitting device moves as shown in FIG. At this time, the second piston 52 and the third piston 52
Since the gap S between the first piston 53 and the gap S between the piston 53 is eliminated, the second piston 52 moves to the left together with the first piston 53 to generate a hydraulic pressure in the output chamber 64, and the pressure in the output chamber 64 is reduced. The fluid is supplied to the left and right front wheel cylinders 6 and 7 via the output ports 4a and 5a → the flow path switching valve 17 and the hold valve 9 to operate the left and right front wheel brakes. Also, the boost chamber 46 of the spool piston 22
The internal pressure fluid is also supplied to the wheel cylinder 8 of the rear wheel as it is via the hold valve to operate the brake of the rear wheel.

The spool piston 22 is moved left and right so that the hydraulic pressure of the boost chamber 46 acting on the left end of the spool piston 22 and the hydraulic pressure of the master cylinder acting on the right end of the diaphragm piston 21 are balanced. By moving, the hydraulic pressure in the boost chamber 46 increases proportionally to the master cylinder hydraulic pressure (power boost).
Is done. The boost ratio is determined by the ratio A5 / A4 of the area A4 at the left end of the spool piston 22 and the pressure receiving area A5 at the right end of the diaphragm piston 21 (see FIG. 3). The brake is applied to both the front and rear wheels by the increased (boosted) hydraulic pressure. On the other hand, the hydraulic pressure acting on the input fluid chamber 62 of the left front wheel hydraulic pressure transmitting device 4 via the first input port 3a of the control valve 3 and the right front wheel hydraulic pressure via the second input port 3b of the control valve 3 Due to the hydraulic pressure acting on the input liquid chamber 62 of the transmission device 5, the first piston 51 in the left and right front wheel hydraulic pressure transmission devices 4 and 5 also moves to the left in the drawing as the second piston 52 moves.

When the brake is released, the spool piston 22 in the control valve 3 returns to the initial position,
The pressure fluid in the pressure introduction chamber 63 of the hydraulic pressure transmission device is supplied to the boost chamber 46 of the spool piston 22 → the flow path 42 → the port member 2.
7, the fluid returns to the reservoir 18 via the first passage 39, the first to third pistons 51 to 53 in the hydraulic pressure transmitting devices 4 and 5 also return to the initial positions, and the pressurized fluid in the output chamber 64 is also released. The front wheel brake is released. Also, in the rear wheel brake, the hydraulic pressure in the boost chamber 46 of the spool piston 22 is controlled by the reservoir 18.
The brakes are released because they are released. As described above, when the brake is operated, the first piston 51 in the hydraulic pressure transmitting devices 4 and 5 moves to the left by the hydraulic pressure from the master cylinder, and the volume of the input liquid chamber 62 increases, so that the pressure from the master cylinder increases. Since the discharged liquid is absorbed, the amount of depression of the brake pedal increases as the depression force of the brake pedal increases, and a suitable operation feeling can be obtained.

[At the time of anti-lock control] If there is a possibility that the wheels may be locked during the brake operation, the signal from the wheel speed sensor S switches the flow path switching valve 17 in accordance with a command from an electronic control unit (ECU). As a result, the output chamber 64 of each of the hydraulic pressure transmitting devices 4 and 5 is disconnected from the hold valve 9 of the left and right front wheel piping system, the hold valve 9 is connected to the boost chamber 46, and the control valve 3 and the left and right hydraulic pressure transmitting The devices 4 and 5 are maintained in the state at the time of braking. Specifically, when the flow path switching valve 17 is switched, the hold valve 9 is closed to maintain the wheel cylinder pressure, and then when the decay valve 10 is opened, the pressure fluid in the wheel cylinders 6 to 8 returns to the reservoir 11. To reduce the wheel cylinder pressure. When it is necessary to repressurize, the decay valve 10 is closed and the hold valve 9 is closed.
, The hydraulic pressure from the accumulator 11 in both the front and rear wheel systems increases from the third input port 3d to the second passage 40 of the port member 27.
→ The center flow path 42 of the spool piston 22 of the control valve 3 → the boost chamber 46 → is supplied to the wheel cylinders 6 to 8 via the first output port 3c and repressurized. At the time of pressure reduction during the antilock control, the fluid pressure from the wheel cylinder can be directly returned to the reservoir from the decay valve 10, so that the brake fluid at the time of reducing the wheel cylinder pressure during the antilock control as in the related art is used. A hydraulic pump for refluxing to the pressure source can be dispensed with.

[Automatic Brake] In the case where slippage occurs in the drive wheels when the vehicle starts, the distance between the vehicles is abnormally shortened, or when it is necessary to apply the brake to secure the stability of the vehicle body when turning (automatic braking) ), The electronic control unit (ECU) is operated by a signal from a wheel speed sensor S, an inter-vehicle distance sensor (not shown), or the like to cause the electronic control unit (ECU) to switch to the normally closed second switching valve
6 and the normally open first switching valve 15 is closed. As a result, the hydraulic pressure in the accumulator 11 is directly supplied to the wheel cylinder via the opened second switching valve 16 in the rear wheel system, and the hydraulic pressure from the accumulator 11 is supplied from the first output port 3c to the flow path in the front wheel system. The second piston 52 and the third piston 5 of the hydraulic pressure transmitting devices 4 and 5 are introduced into the pressure introduction chamber 63 of the hydraulic pressure transmitting devices 4 and 5
3 is moved to the left in the figure, the poppet valve 59 is closed, and a hydraulic pressure is generated in the output chamber 64.
The brakes are supplied to the front left and right wheels via the right wheel to apply an appropriate braking force to the front left and right wheels to eliminate slips and the like. The adjustment of the hydraulic pressure in the wheel cylinder at this time is performed by the hold valve 9, the decay valve 10 and the
Open and close. By the way, if the first and second pistons 51 and 52 are integrally formed, the volume of the input liquid chamber 62 in the hydraulic pressure transmission device 4 and 5 increases when the automatic brake is activated, and the input liquid is temporarily stopped. There is a possibility that the pressure in the chamber 62 and the piping system connected thereto becomes negative pressure, and air flows into the input liquid chamber and the like. However, in the present control device, the first and second pistons 51 and 52 are formed separately so as to be movable relative to each other, so that the first piston 51 does not move and the input liquid No negative pressure is generated in the chamber 62 or the like.

[Emergency braking] When the electronic control unit (ECU) determines that a sudden braking operation has been performed based on the signal of the brake stroke sensor B, the first switching valve 1
By closing the valve 5 and opening the second switching valve 16, a large hydraulic pressure in the accumulator 11 acts on the wheel cylinders 6 to 8 of the front and rear wheels. [Fail] In the present hydraulic pressure transmitting device, when the pressurized fluid from the accumulator 11 is not supplied for some reason and the boosting function is not performed (at the time of failure), the spool piston 22 in the control valve moves. However, no hydraulic pressure is generated in the pressure introducing chamber 63, and the second piston 52 and the third piston 53 do not move with the hydraulic pressure in the pressure introducing chamber 63. However, the hydraulic pressure generated in the tandem master cylinder acts from the first and second input ports 3a and 3b of the control valve 3 to the input liquid chambers 62 of the left and right front wheel hydraulic pressure transmitting devices 4 and 5, and the first piston 51, The second piston and the third piston are moved together to generate a hydraulic pressure in the output chamber, and this hydraulic pressure is directly transmitted to the front wheel cylinder to perform a braking action. In this hydraulic pressure transmitting device, the diameter of the hydraulic piston of the tandem master cylinder can be made relatively small, and the pressure receiving area of the third piston 53 of the hydraulic pressure transmitting device can be made large. Sufficient braking force can be secured even during a failure.

The second tandem master cylinder 2
When the system of the hydraulic pressure generation chamber 2b fails, the hydraulic pressure generated in the first hydraulic pressure generation chamber 2a of the tandem master cylinder 2 flows into the second input liquid chamber 29 of the control valve 3,
The diaphragm piston 21 and the spool piston 22 are moved to the left, the brake is directly applied to the rear wheel by the hydraulic pressure from the accumulator, and the front and rear wheels are moved by the second and third pistons in the left and right front wheel hydraulic pressure transmitting devices. A hydraulic pressure is generated in the output chamber 64 to operate the brake. When the system of the first hydraulic pressure generation chamber 2a of the tandem master cylinder 2 fails, the hydraulic pressure generated in the second hydraulic pressure generation chamber 2b causes the pilot piston 20 in the control valve 3 to move and the diaphragm piston 21 to move. And the brakes act on the left and right front and rear wheels in the same manner as described above.

[During Operation of Electrically Controlled Brake System] When the driver operates the hand lever or the hand switch,
Also, a signal current corresponding to the operation amount is output from the electronic control unit to the electromagnetic proportional control valve 70, and the normally-open third switching valve 73 is closed, and the electromagnetic proportional control valve 70 controls the hydraulic pressure according to the operation amount. The hydraulic pressure of the accumulator 11 is controlled and output from the output port 71. The fluid pressure from the output port 71 flows into the second input fluid chamber 29 of the control valve 3 and acts on the diaphragm piston 21 in the control valve 3. When hydraulic pressure acts on the diaphragm piston 21,
The piston 21 moves leftward in FIG. 2, and the spool piston 22 also moves leftward in FIG.

Further movement of the spool piston 22 causes the central flow passage 42 in the spool piston 22 to
→ The second passage 40 of the port member 27 → The third input port 3d
The pressure fluid in the accumulator 11 is communicated with the accumulator 11 through the central passage 42 → the boost chamber 46 →
The flow path 45 is introduced into the pressure introduction chamber 63 of the front wheel hydraulic pressure transmitting devices 4 and 5, and the second piston 52 in the hydraulic pressure transmitting device moves as shown in FIG. At this time, the poppet valve 59 is seated while the second piston 52 moves by the gap S, and contacts the third piston 53 by further movement.
The piston 52 moves to the left together with the third piston 53 to generate a hydraulic pressure in the output chamber 64, and the pressure fluid in the output chamber 64 is supplied to the left and right front and rear wheels via the flow path switching valve 17 and the hold valve 9. It is supplied to the cylinders 6 and 7 to operate the left and right front wheel brakes. The pressure fluid in the boost chamber 46 of the spool piston 22 is also supplied to the rear wheel cylinder via the hold valve as it is, and the rear wheel brake is actuated.

The spool piston 22 moves left and right so that the hydraulic pressure due to the hydraulic pressure in the boost chamber 46 acting on the left end of the spool piston 22 and the hydraulic pressure acting on the right end of the diaphragm piston 21 are balanced. The hydraulic pressure of the chamber 46 is increased (boosted) in proportion to the output hydraulic pressure of the electromagnetic proportional control valve 70. The boosting ratio is a ratio A5 / A between the area A4 at the left end of the spool piston 22 and the pressure receiving area A5 at the right end of the diaphragm piston 21.
4 The brake is applied to both the front and rear wheels by the increased (boosted) hydraulic pressure.

When the brake is released, the electromagnetic proportional control valve 70 returns to the initial position to shut off the flow path and
The switching valve 73 opens the flow path and returns the fluid pressure in the second input fluid chamber 29 in the control valve 3 to the master cylinder. As a result, the spool piston 22 in the control valve 3 returns to the initial position by the hydraulic pressure in the boost chamber 46 and the return spring 43, and communicates the groove 41 with the first passage 39 of the port member 27. From the flow path 42 → the groove 41 → the first passage 39 → the second output port 3e → the first switching valve 15 to the reservoir 18. When the hydraulic pressure in the boost chamber 46 is released, the pressure fluid in the pressure introduction chamber 63 of the hydraulic pressure transmission devices 4 and 5 also flows into the reservoir 18 via the flow path 42 of the spool piston 22 → the first path 39 of the port member 27. In order to recirculate, the first to third pistons 51 to 53 in the hydraulic pressure transmitting devices 4 and 5 return to the initial position,
The pressure fluid in the output chamber 64 is also released, and the front wheel brake is released. The rear wheel brake is also released because the hydraulic pressure in the boost chamber 46 is released to the reservoir 18.

When the wheels are likely to be locked during the operation of the electrically controlled brake, a signal from the wheel speed sensor S is used to issue a signal from the electronic control unit (ECU) to switch the flow path switching valve 1.
7 is switched. As a result, the output chamber 64 of each hydraulic pressure transmission device 4, 5 is cut off from the hold valve 9 of the left and right front wheel piping system,
Further, the hold valve 9 is connected to the boost chamber 46, and the electromagnetic proportional valve 70, the control valve 3, and the left and right hydraulic pressure transmitting devices 4, 5 are maintained in a state when the brake is operated. In this state, the hold valve 9, the decay valve 10 are opened and closed according to the state of the wheels to maintain, reduce, and re-pressurize the brake hydraulic pressure. This aspect is the same as that of the hydraulic brake system.

When the electronic control unit (ECU) judges the state even in the case of a sudden braking operation in which the hand lever is suddenly operated, the first switching valve 15 is closed and the second switching valve 16 is opened, whereby the accumulator 11 is opened. Large hydraulic pressure acts on the wheel cylinders 6 to 8 of the front and rear wheels.

[0045]

As described in detail above, according to the present invention, 1) the front wheel system is further made independent of the left and right wheels while the brake piping system is made up of two systems of front and rear wheels, and the rear wheel system is shared by the left and right wheels. Since the piping system is used, even if one of the front wheel systems fails, the braking force of the front wheel on the other side is maintained, so that a situation in which the braking force is insufficient can be prevented. 2) Since the hydraulic pressure from the accumulator in the brake hydraulic pressure control device can be supplied directly to the brake cylinder without providing a hydraulic pressure transmission device in the rear wheel piping system, it is possible to prevent the device from increasing in size and cost. it can. 3) The mountability of the vehicle is improved by using a configuration in which the booster is separated from the master cylinder. 4) Since the hydraulic pump and various valves can be controlled by the electronic control device based on information from various sensors, various brake modes can be realized only by changing the program in the electronic control device. 5) Re-pressurization, depressurization, holding, etc. of the brake fluid pressure at the time of anti-lock control, traction control, etc. can be realized with high accuracy, and the feeling of the brake can be improved. Since the second piston is separated, the first piston in the hydraulic pressure transmitting device does not move during the automatic braking operation, and no negative pressure is generated in the input liquid chamber or the like in the device. 7) When the pressure is reduced during the antilock control, the hydraulic pressure from the wheel cylinder can be directly returned to the reservoir from the decay valve, thereby eliminating the need for the conventional hydraulic pump for antilock control. Is simplified. 8) An electromagnetic proportional control valve is arranged between the control valve and the accumulator, and the electromagnetic proportional control valve is actuated by a command from a manual operation unit such as a brake lever or a hand switch so that the brake can be operated. Therefore, application to a vehicle for a physically handicapped person can be easily performed. Excellent effects can be achieved.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a brake fluid pressure control device according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a control valve and a hydraulic pressure transmission device in the brake hydraulic pressure control device.

FIG. 3 is a state diagram of the hydraulic pressure transmission device when a brake is operated.

FIG. 4 is an overall configuration diagram of a conventional brake fluid pressure control device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Brake pedal 2 Tandem master cylinder 3 Control valve 4 Left front wheel hydraulic pressure transmission device 5 Right front wheel hydraulic pressure transmission device 6 Left front wheel cylinder 7 Right front wheel cylinder 8 Right and left rear wheel cylinders 9 Hold valve 10 Decay valve 11 Accumulator 12 Pressure Sensor 13 Hydraulic pump 14 Relief valve 15 First switching valve 16 Second switching valve 17 Flow path switching valve 18 Reservoir 20 Pilot piston 21 Diaphragm piston 22 Spool piston 24 First cylinder 25 Second cylinder 26 Third cylinder 27 Port member 28 First input liquid chamber 29 Second input liquid chamber 30 Atmosphere chamber 31, 33 Flow path 34 First spring 35 Second spring 36 Diaphragm 37 Liquid chamber 38 Engagement projection 39 First passage 40 First Passage 41 Groove formed in spool piston 42 Flow passage formed in the center of spool piston 43 Return spring 45 Flow passage 46 Boost chamber 51 First piston 52 Second piston 53 Third piston 54 Spring holder 55, 56 Spring 57 Passage 58 Liquid chamber 59 Poppet valve 60 Poppet spring 61 Valve element 62 Input liquid chamber 63 Hydraulic pressure introduction chamber 64 Output chamber 65 Liquid chamber 66 Stopper 70 Electromagnetic proportional control valve 71 Output port 72 Input port 73 Normally open third switching valve 75 Check valve

Claims (4)

[Claims] A control valve for outputting a hydraulic pressure of a pressure source increased in proportion to a hydraulic pressure generated in a master cylinder, a piston is operated by an output hydraulic pressure from the control valve, and a hydraulic pressure is increased. And a pair of hydraulic pressure transmitting devices 4 and 5 which generate the hydraulic pressure. The pair of hydraulic pressure transmitting devices 4 and 5 are respectively arranged in independent piping systems of the left and right front wheel systems, and the control valve is controlled by an electronic control device. Pressure source 1 output from electromagnetic proportional control valve 70 operated by a signal
The fluid pressure in the control valve 3 is switched by the fluid pressure from the control valve 3 so that the fluid pressure of the pressure source increased in proportion to the output pressure from the electromagnetic proportional control valve 70 can be output. The output hydraulic pressure can be directly supplied to the rear wheel cylinder 8 and the pistons of the pair of front wheel hydraulic pressure transmitting devices 4 and 5 are actuated to change the hydraulic pressure generated by the front wheel hydraulic pressure transmitting device to the corresponding left and right wheels. The brake fluid pressure control device is configured to supply the brake fluid to the front wheel cylinders 6 and 7. 2. An output port of the electromagnetic proportional control valve is communicated with a master cylinder via a valve that shuts off a flow path when the electromagnetic proportional control valve is operated.
4. The brake fluid pressure control device according to item 1. 3. The brake fluid pressure control device according to claim 1, wherein the electronic control device outputs the command signal by operating a manual operation member. 4. A master cylinder, an electromagnetic proportional control valve for controlling and outputting a pressure of a pressure source by a command signal of an electronic control unit, and controlling a pressure of the pressure source in proportion to a fluid pressure of an input fluid chamber. It has a control valve that outputs, a flow path that connects the output ports of the master cylinder and the electromagnetic proportional control valve to the input liquid chamber of the control valve, respectively, and a brake device that operates by the output hydraulic pressure of the control valve. Brake fluid pressure control device.