JP2561218Y2 - ABS / TCS modulator - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention makes it possible to optimally control the braking force of a wheel so as to prevent the locking of the wheel when the vehicle is braking, and to prevent the wheel from slipping when the vehicle starts moving. The present invention relates to an ABS / TCS modulator capable of applying an appropriate braking force to wheels as much as possible.

[0002]

2. Description of the Related Art In recent years, skid control (ABS) for avoiding locking of wheels at the time of braking has been proposed for the purpose of facilitating driving operation of a driver and improving starting, acceleration and steering stability. The development of an ABS / TCS modulator having a function of a traction control (TCS) for avoiding excessive slip of the drive wheels at the time of sudden start, rapid acceleration, and the like has been actively performed. This kind of ABS
/ TCS modulator is disclosed in JP-A-2-23125.
No. 6 is known.

[0003] Referring to FIG. 4, a schematic structure of a brake device described in Japanese Patent Application Laid-Open No. 2-231256 will be described. The brake device comprises a master cylinder M and a booster 10.
0, pilot-type on-off valves 101 and 102, three-position switching valve 103, reservoir 104, pumps 105 and 106, motor 108 for driving both pumps, control circuit ECU, and a fluid path connecting these valves and devices. Have been.

The operation of this brake device will be briefly described. (1) During normal braking, each switching valve is in the state shown in the figure. For this reason, when hydraulic pressure is generated in the master cylinder M by depressing the brake pedal, the brake hydraulic pressure generated in the master cylinder M is transmitted from the discharge port of the master cylinder M to the brake via the pilot open / close valve 102 and the three-position switching valve 103. It is supplied to the cylinder and the brake works.

(2) If a skid occurs during the braking operation (during anti-skid control), the signal from the ECU switches the three-position switching valve 103 from the state shown in the figure, drives the motor 108, and activates the hydraulic pump 105. Operate. The brake fluid flowing from the brake cylinder 107 into the reservoir 104 is returned to the master cylinder M by the hydraulic pump 105. In accordance with the skid state of each wheel, the three-position switching valve 103 is switched by a signal from the ECU, and the braking force holding, loosening, and filling are repeated, and anti-skid control is performed. At this time, the traction control hydraulic pump 106 is also operated by the motor 108. However, since the pilot on-off valve 101 is closed by the hydraulic pressure generated in the master cylinder, the supply of the brake fluid to the hydraulic pump 106 is limited. No, the pump 106 has no pressurizing action.

(3) When a slip occurs in the drive wheels when the vehicle starts (at the time of traction control), the hydraulic pump 106 is operated by a signal from the ECU and the brake fluid is discharged. Open / close valve 1
02 closes. At the same time, the brake fluid pressurized by the hydraulic pump 106 is supplied to the brake cylinder via the three-position switching valve 103 to apply a braking force to the wheels.
In this state, by switching the three-position switching valve 103 with a signal from the ECU, the three-position switching valve 103 is switched according to the slip state of each drive wheel.
The braking force holding, loosening, and putting are repeated, and traction control is performed. At this time, the anti-skid hydraulic pump 105 is also operated by the motor 108, but the pump 105 does not pressurize. As described above, the locking tendency of the drive wheels and the slip of the wheels at the time of starting are controlled, so that the vehicle can be decelerated or stopped or started smoothly in a stable state.

[0007]

However, in the above ABS / TCS modulator, the traction control pump 106 and the anti-skid brake pump 105 are driven by one motor 108. At the time of or during the anti-skid brake system, the brake fluid is not supplied to the other pump. As a result, the brake fluid is confined in the pump in the no-load state, a vacuum chamber is created in the pump chamber, and a state in which the vacuum chamber rapidly disappears is repeated, so-called a cavitation state occurs, and abnormal noise is generated. Cause.
It is also conceivable to provide a valve on the suction side of the pump to prevent the occurrence of cavitation,
Since such a valve generally has an inner diameter smaller than the diameter of the pipe, the brake fluid is throttled at this portion, which in turn causes a problem that the suction performance at the time of operating the pump deteriorates.

[0008]

Accordingly, the present invention is directed to a pump in which an anti-skid brake pump and a traction control pump are driven by the same motor.
In the BS / TCS modulator, the liquid passage of the traction control hydraulic pump is set to an open circuit while the anti-skid hydraulic pump is driven, so that the discharge liquid from the traction control hydraulic pump circulates.
ABS that can prevent the above-mentioned cavitation
The purpose of the present invention is to obtain a TCS modulator. Further, a conventional cut valve and a pressurizing piston are integrated, and the cut valve is also operated by the hydraulic pressure from the master cylinder, thereby reducing the cost of the ABS / TCS.
The aim is to obtain a modulator.

[0009]

SUMMARY OF THE INVENTION Accordingly, the present invention provides an anti-skid hydraulic circuit and an anti-skid liquid provided in the above-mentioned circuit, which functions to pump out a liquid discharged from a wheel cylinder during anti-skid control. A pressure pump, a traction control hydraulic circuit, and a brake fluid that is sucked from a low-pressure accumulator that is provided during the traction control and accumulates a predetermined hydraulic pressure only during the traction control and is further discharged by the anti-skid hydraulic circuit through the anti-skid hydraulic circuit. In the ABS / TCS modulator having a traction control hydraulic pump capable of applying a brake hydraulic pressure to a wheel cylinder and a common motor for driving each of the pumps, suction of the traction control hydraulic pump is performed. For communicating the flow path and the discharge path Which is characterized in that a control valve for the circuit and opened by hydraulic pressure from the master cylinder during the

Further, in the ABS / TCS modulator, a master cylinder and a hold valve communicate with each other in a non-traction control passage in a fluid passage connecting the anti-skid hydraulic circuit and the traction control hydraulic circuit. A pressurizing piston / cut valve which cuts off the communication between the cylinder and the hold valve and generates a hydraulic pressure by a discharge pressure from a traction control hydraulic pump is provided. It is assumed that.

[0011]

When the hydraulic pressure is not generated in the master cylinder M, the switching valve 10 is operated by the valve 22 as shown in FIG.
7 and 28 are shut off. When a hydraulic pressure is generated in the master cylinder M, the piston 21 moves to the right and pushes the valve 22 to communicate with the flow paths 27 and 28. During the anti-skid control, the switching valve 10 is open. Therefore, even if the TCS pump 9 is driven at the same time as the anti-skid hydraulic pump 5, the liquid discharged from the TCS pump 9 returns to the suction port of the TCS pump 9 again. And the TCS pump 9 can be operated in a no-load state.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a hydraulic piping diagram in which an ABS / TCS modulator according to an embodiment of the present invention is incorporated in a hydraulic circuit of a driving wheel. Each valve provided in these hydraulic circuits is controlled by a known electronic control unit (not shown).

In the drawing, M is a master cylinder, 1 is a cut valve, 2 is a hold valve, 3 is a decay valve, and 4 is a reservoir. These are connected in series for each drive wheel from the master cylinder M to the reservoir 4. It is connected. The pipeline between the hold valve 2 and the decay valve 3 is connected to the wheel cylinder of the brake B provided on the drive wheel, and the pipeline between the decay valve 3 and the reservoir 4 is The suction port of the skid hydraulic pump 5 is connected. The discharge port of the anti-skid hydraulic pump 5 is connected to a pipe between the cut valve 1 and the hold valve 2 via a check valve 6. The anti-skid hydraulic pump 5 is driven by a common motor 12 together with a TCS pump 9 described later.

A pressurizing piston 7 constituting a TCS unit described later is connected to a pipeline between the cut valve 1 and the hold valve 2. The TCS unit includes a pressurizing piston 7, a low-pressure accumulator 8, a TCS pump 9, a switching valve 10, and a relief valve 11. The pressurizing piston 7, the TCS pump 9, and the accumulator 8 are connected in series, and a switching valve 10 and a relief valve 11 are connected in parallel with the TCS pump 9. The switching valve 10 is provided so that the TCS pump 9 is driven by an open circuit in a no-load state during anti-skid control.

The structure of the switching valve 10 will be described with reference to FIG. The switching valve 10 includes a piston 2 housed in a valve body.
1, a valve 22, springs 23 and 24, and a liquid chamber 25 is formed by the piston 21 and the valve body. The liquid chamber 25 is communicated with the master cylinder M. The piston 21 has a valve opening rod 26,
A valve 22 is provided corresponding to the rod 26, and the piston moves to the right in the drawing against the urging force of the spring 23, thereby moving the valve 22 to the right and the flow path 27,
28 can be communicated.

Therefore, in this switching valve 10, when no hydraulic pressure is generated in the master cylinder M, the flow passages 27 and 28 are shut off by the valve 22 as shown in FIG.
When a hydraulic pressure is generated in the master cylinder M, the piston 21 moves to the right and pushes the valve 22 to communicate with the flow paths 27 and 28. Therefore, even if the TCS pump 9 is driven at the same time as the anti-skid hydraulic pump 5 during the anti-skid control, an open circuit in which the liquid discharged from the TCS pump 9 is returned to the suction port of the TCS pump 9 again, and no load is applied. Driving with.

The pressurizing piston 7 is for supplying brake fluid to the anti-skid hydraulic circuit by the action of the discharge brake fluid pressure from the TCS pump 9 during traction control. It is divided and formed. One compartment is TC
The other section is connected between the cut valve 1 and the hold valve 2 of the anti-skid hydraulic circuit via a liquid passage. In the other section, a pressure spring 71 that constantly presses the pressure piston 9 to the left in the drawing is arranged. The low-pressure accumulator 8 is for accumulating the brake fluid in the pressurizing piston 7 in the accumulator during non-traction control. The low-pressure accumulator 8 has an accumulator spring 8 for urging the piston to the left in the drawing.
1 is arranged.

The pressurizing spring 71 in the pressurizing piston and the accumulator spring 8 in the accumulator
The spring load 1 is set larger in the pressure spring 71 than in the accumulator spring 81. Therefore, in the hydraulic circuit of the TCS unit, during non-traction control, the pressurizing piston 7 is pressed to the left by the pressurizing spring 71 as shown in the figure, and the brake fluid in the pressurizing piston is released from the accumulator spring. The pressure is accumulated in the accumulator chamber while pushing the accumulator piston 82 rightward in the figure against the pressure 81. At this time, the section of the pressurizing piston 7 on the side of the anti-skid hydraulic circuit is filled with the brake fluid in communication with the anti-skid circuit.

The TCS pump 9 is operated by a motor during traction control, and generates a hydraulic pressure in the circuit when the switching valve 10 is closed. Also,
The TCS pump is driven in conjunction with the anti-skid hydraulic pump 5 at the time of ABS operation, but the brake fluid is circulated through the accumulator 8 → the TCS pump 9 → the switching valve 10 → the accumulator 8 by keeping the switching valve 10 open. Do not generate pressure in the circuit.

Subsequently, the ABS / T having the above configuration
The operation of the CS modulator will be described. (1) During normal braking During normal braking, each switching valve is in the state shown in the figure. When the brake pedal is depressed, hydraulic pressure is generated in the master cylinder M, and the generated brake hydraulic pressure is transmitted from the discharge port of the master cylinder M to the cut valve 1,
The brake is supplied to the brake cylinder via the hold valve 2 to operate the brake.

(2) At the time of anti-skid control If the wheel speed sensor (not shown) detects the skid of the wheel during braking, the electronic control circuit determines the hold valve 2, the decay valve 3 and the anti-skid according to the skid state of the wheel. The hydraulic pump 5 is controlled. When the brake holding signal is output, the hold valve 2 closes, the fluid path between the master cylinder and the wheel cylinder is cut off, and the brake fluid pressure in the wheel cylinder is maintained. When a brake release signal is output from an electronic control unit (not shown), the hold valve 2 is closed to cut off the fluid path between the master cylinder and the wheel cylinder, and at the same time, the decay valve 3 is opened to disconnect the fluid path between the wheel cylinder and the reservoir. The brake fluid in the communication wheel cylinder is discharged to the reservoir 4 and the brake is released.

Then, the brake fluid discharged to the reservoir 4 is returned to the master cylinder M by the anti-skid hydraulic pump 5 which operates simultaneously with the start of the hydraulic control. The hydraulic control of each wheel cylinder is performed independently according to the state of each wheel. At this time, the TCS pump 9 is also driven by the motor 12 together with the anti-skid hydraulic pump 5, and the switching valve 10 in the TCS pump 9 switches the flow passages 16 and 17 by hydraulic pressure from the master cylinder. Due to the communication, the drive is in a no-load state.

(2) Traction control When the vehicle starts moving, if a wheel speed sensor (not shown) detects that the driving wheels of the engine suddenly start and the driving torque of the engine is too large to cause a slip larger than a predetermined value, known electronic control is performed. The signal is input to the device.

The electronic control circuit controls the hold valve 2, the decay valve 3, and the anti-skid hydraulic pump 5 according to the slip state of the wheels. Now, when a drive slip control signal is output from the electronic control unit, the cut valve 1 is excited and the communication between the master cylinder M and the hold valve 2 is cut off. On the other hand, the switching valve 10 maintains the pressure piston 7 and the accumulator 8 in a non-communication state because the hydraulic pressure from the master cylinder does not act. At the same time TC
The S pump 9 starts operating, and the TCS pump 9 sucks the brake fluid from the accumulator 8.

At this time, high pressure brake fluid (for example, 1 to 10 kg / c) is supplied to the TCS pump 9 from the accumulator.
m ² ), the pump efficiency is improved. The brake fluid discharged from the TCS pump 9 is supplied to the pressure piston 7 and moves the pressure piston 7 rightward against the pressure spring 71. The rightward movement of the pressure piston 7 causes the brake fluid in the pressure piston to be supplied to the brake cylinder via the hold valve 2. Thereby, the brake is applied to the drive wheels, and the drive slip is reduced. During the slip control, the electronic control unit controls each of the hold valve 2 and the decay valve 3, and the braking force holding, loosening, and filling are repeated according to the slip state of each drive wheel.

As described above, the drive slip can be controlled to an optimum state. Then, when the drive slip is almost eliminated, the electronic control unit detects this and stops driving the TCS pump 9 and switches the cut valve 1 to the illustrated state. As described above, according to the present invention, while the anti-skid control is being performed, the TCS pump 9 is set to the no-load operation by the open circuit via the switching valve 10, thereby preventing the occurrence of cavitation as in the related art. Cut off.

Next, a second embodiment of the present invention will be described with reference to FIG. The cut valve 1 in the first embodiment is constituted by an electromagnetic valve that switches the flow path by a signal from the ECU when the traction control is started. In the present embodiment, the cut valve 1 in the first embodiment is used. And the pressurizing piston 7 are integrated to enable the cut valve to be actuated by hydraulic pressure. Pressurized piston combined cut valve 3
Reference numeral 0 denotes a piston 31 housed in a valve body, a valve 32, and a spring 37.
Liquid chambers 33 and 36 are formed by 1 and the valve body. The liquid chamber 33 is connected to the master cylinder M via a valve 32 and a flow path 34 and is also connected to the hold valve 2 via a flow path 35. The liquid chamber 36 is T
The discharge port of the CS pump 9 communicates with the discharge port. Piston 31
Holds the valve 32 movably in the axial direction by a predetermined distance, and is pressed leftward in the figure by a spring 37 to communicate the flow path 34 and the liquid chamber 33 in the state shown in the figure.

Accordingly, in the pressurized piston / cut valve 30, no hydraulic pressure is generated from the TCS pump 9 during non-traction control, so that the piston 31 assumes the state shown in FIG. 3
4 → Valve 32 → Liquid chamber 33 → Flow path 35 to be supplied to the brake cylinder. On the other hand, during traction control, T
The hydraulic pressure generated by the CS pump 9 causes the piston 31 to move rightward, and the valve 32 also moves rightward by the spring 38 to cut off the communication between the flow path 34 and the liquid chamber 33. Then, the hydraulic pressure generated by the TCS pump 9 moves the piston 31 further rightward, and the hydraulic pressure generated in the liquid chamber 33 is supplied to the brake cylinder via the hold valve 2. This controls the slip of the drive wheels. As described above, in this embodiment, the cut valve and the pressurizing piston are integrally formed, and the cut valve can also be controlled by the hydraulic pressure. Therefore, it is not necessary to use a conventional electromagnetic valve, and the cost is reduced. Can be greatly reduced.

[0029]

[Effect of the invention] As described in detail above, according to the invention,
While the anti-skid control is being performed, the TCS pump is operated without load by the open circuit, so that the occurrence of cavitation as in the related art can be prevented.
Further, since the cut valve can be controlled by the hydraulic pressure, it is not necessary to use a conventional electromagnetic valve, and the cost can be reduced. As a result, an ABS / TCS modulator that is extremely safe and inexpensive can be obtained.

[Brief description of the drawings]

FIG. 1 is a hydraulic piping diagram in which an ABS / TCS modulator according to a first embodiment of the present invention is incorporated in a hydraulic circuit of a driving wheel.

FIG. 2 is a structural diagram of a switching valve arranged in an ABS / TCS modulator.

FIG. 3 is a hydraulic piping diagram in which an ABS / TCS modulator according to a second embodiment of the present invention is incorporated in a hydraulic circuit of a driving wheel.

FIG. 4 is a hydraulic piping diagram in which a conventional ABS / TCS modulator is incorporated in a hydraulic circuit of a driving wheel.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cut valve 2 Hold valve 3 Decay valve 4 Reservoir 5 Anti-skid hydraulic pump 7 Pressurizing piston 8 Accumulator 9 TCS pump 10 Switching valve 11 Relief valve 12 Motor 30 Pressurizing piston cut-off valve

Claims (2)

(57) [Scope of request for utility model registration] 1. An anti-skid hydraulic circuit, an anti-skid hydraulic pump provided in the circuit for pumping out a drain from a wheel cylinder during anti-skid control, and a traction control hydraulic circuit. ,
The brake fluid is suctioned from a low-pressure accumulator that is provided during the traction control and stores a predetermined fluid pressure only during the traction control, and the brake fluid pressure is applied to the wheel cylinder via the anti-skid hydraulic circuit by the discharge pressure. In an ABS / TCS modulator having a traction control hydraulic pump and a common motor for driving each of the pumps, a master circuit is provided in a circuit that connects a suction path and a discharge path of the traction control hydraulic pump. An ABS / TCS modulator comprising a switching valve for opening said circuit by hydraulic pressure from a cylinder. 2. An anti-skid hydraulic circuit, an anti-skid hydraulic pump provided in the circuit for pumping a drain from a wheel cylinder during anti-skid control, and a traction control hydraulic circuit. ,
The brake fluid is suctioned from a low-pressure accumulator that is provided during the traction control and stores a predetermined fluid pressure only during the traction control, and the brake fluid pressure is applied to the wheel cylinder via the anti-skid hydraulic circuit by the discharge pressure. In an ABS / TCS modulator having a traction control hydraulic pump and a common motor for driving each of the pumps, a hydraulic path connecting the anti-skid hydraulic circuit and the traction control hydraulic circuit. During non-traction control, the master cylinder and the hold valve communicate with each other, and during traction control, the communication between the master cylinder and the hold valve is cut off, and hydraulic pressure is generated by the discharge pressure from the traction control hydraulic pump. And a switching valve that opens the circuit by hydraulic pressure from a master cylinder in a circuit that connects the suction path and the discharge path of the traction control hydraulic pump. An ABS / TCS modulator, characterized in that: