JPH0556712U - ABS / TCS modulator - Google Patents

Abstract

(57) [Summary] [Purpose] While the anti-skid hydraulic pump is in operation, the fluid passage of the traction control hydraulic pump is an open circuit so that the discharge liquid from the traction control hydraulic pump circulates. The traction control hydraulic pump prevents cavitation. [Structure] The switching valve 10 shuts off the flow paths 27 and 28 by a valve 22 as shown in the figure in a state where no hydraulic pressure is generated in the master cylinder M. When hydraulic pressure is generated in the master cylinder M, the piston 21 moves to the right and the valve 22
Press to connect the flow paths 27 and 28. Since the switching valve 10 is opened during the anti-skid control, even if the TCS pump 9 is driven at the same time as the anti-skid hydraulic pump 5, the discharge liquid from the TCS pump 9 is returned to the suction port of the TCS pump 9 again. As a result, the TCS pump 9 can be operated in an unloaded state.

Description

[Detailed description of the device]

[0001]

[Industrial application]

 The present invention makes it possible to optimally control the braking force of the wheels so as to prevent the locking of the wheels when the vehicle is being braked, and to prevent the wheels from slipping when the vehicle starts moving. The present invention relates to an ABS / TC S modulator capable of being powered.

[0002]

[Prior Art]

 In recent years, for the purpose of facilitating the driver's driving operation and improving the starting, acceleration and steering stability, skid control (ABS) for avoiding wheel locking phenomenon during braking and sudden start of the vehicle ABS / TCS modulators that have a function as a traction control (TCS) that avoids excessive slippage of the drive wheels that occur during sudden acceleration or the like are being actively developed. As this type of ABS / TCS modulator, the one described in JP-A-2-231256 is known.

Explaining the schematic configuration of the brake device disclosed in Japanese Patent Laid-Open No. 231256/1990 with reference to FIG. 4, the brake device is a master cylinder M, a booster 100, pilot type opening / closing valves 101, 102, and 3 positions. It is composed of a switching valve 103, a reservoir 104, pumps 105 and 106, a motor 108 that drives both pumps, a control circuit ECU, and a liquid path that connects these valves and devices.

The operation of the brake device will be briefly described. (1) During normal braking, each switching valve is in the state shown in the figure. Therefore, 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 transferred from the discharge port of the master cylinder M to the pilot type on-off valve 102 and the three-position switching valve 103. Supplied to the brake cylinder, the brake works.

(2) If a skid occurs during brake operation (during anti-skid control), the signal from the ECU switches the three-position switching valve 103 from the state shown in the figure, and the motor 108 is driven to control the hydraulic pressure. The pump 105 operates. 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 braking force holding, slackening, and refilling are repeated while the three-position switching valve 103 is switched by a signal from the ECU, and anti-skid control is performed. At this time, the traction control hydraulic pump 106 is also operated by the motor 108, but since the pilot type on-off valve 101 is closed by the hydraulic pressure generated in the master cylinder, the brake fluid is supplied to the hydraulic pump 106. Is not performed and the pump 106 has no pressurizing action.

(3) When the drive wheels slip when the vehicle starts (during traction control), the hydraulic pump 106 is activated by a signal from the ECU, and the brake fluid is discharged. The on-off valve 102 is closed. 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 the braking force to the wheels. By switching the three-position switching valve 103 in this state by a signal from the ECU, the braking force is maintained, loosened, and put in repeatedly according to the slip state of each driving wheel, and the traction control is performed. At this time, the antiskid hydraulic pump 105 is also operated by the motor 108, but the pump 105 does not exert a pressurizing action. As described above, the tendency of the drive wheels to lock and the slip of the wheels at the time of starting are controlled, and the vehicle can decelerate or stop in a stable state or smoothly start.

[0007]

[Problems to be solved by the device]

 However, in the ABS / TCS modulator described above, the traction control pump 106 and the anti-skid brake pump 105 are driven by a single motor 108. Therefore, during traction control or the anti-skid brake system, Brake fluid is not being supplied to the other pump. As a result, the brake fluid is confined in the unloaded pump, a vacuum chamber is created in the pump chamber, and it rapidly disappears, resulting in a so-called cavitation condition. It causes a sound. It is also possible to install a valve on the suction side of the pump in order to prevent cavitation, but such a valve generally has an inner diameter smaller than the diameter of the pipe, so the brake fluid is throttled at this part. This time, on the contrary, a problem arises that the suction performance during pump operation deteriorates.

[0008]

[Problems to be solved by the device]

 Therefore, in the present invention, in the ABS / TCS modulator in which the anti-skid brake pump and the traction control pump are driven by the same motor, the anti-skid hydraulic pump is operating while the anti-skid hydraulic pump is operating. The purpose is to obtain an ABS / TCS modulator capable of preventing the above-mentioned cavitation by allowing the liquid passage of the pump to be an open circuit so that the liquid discharged from the hydraulic pump for traction control circulates. Further, it is an object of the present invention to obtain an ABS / TCS modulator which is easy to manufacture by integrating a conventional cut valve and a pressurizing piston so that the cut valve is also operated by the hydraulic pressure from the master cylinder.

[0009]

[Means for Solving the Problems]

 For this reason, the present invention provides a hydraulic circuit for anti-skid, a hydraulic pump for anti-skid which is provided in the circuit and serves to pump out the liquid discharged from the wheel cylinder during anti-skid control, and a hydraulic circuit for traction control. The brake fluid is sucked from the circuit and the low-pressure accumulator that is provided during the traction control and accumulates a predetermined hydraulic pressure only during traction control, and the brake fluid pressure is applied to the wheel cylinders via the anti-skid hydraulic circuit by the discharge pressure. In an ABS / TCS modulator having a traction control hydraulic pump that can be operated and a common motor for driving each of the pumps, the suction passage and the discharge passage of the traction control hydraulic pump are connected to each other. The master cylinder in the circuit Are those by the fluid pressure, characterized in that a control valve for the circuit open,

Further, in the ABS / TCS modulator, the master cylinder and the hold valve are communicated with each other during the non-traction control in the fluid passage communicating the anti-skid hydraulic circuit and the traction control hydraulic circuit. In this case, the master cylinder and the hold valve are cut off at the same time, and a cut valve that doubles as a pressurizing piston that generates hydraulic pressure by the discharge pressure from the hydraulic pump for traction control is provided. Is a means of solving the problem.

[0011]

[Action]

 The switching valve 10 shuts off the flow passages 27 and 28 by the valve 22 as shown in the figure in a state where no hydraulic pressure is generated in the master cylinder M. When 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. Since the switching valve 10 is open during the anti-skid control, 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 is returned to the suction port of the TCS pump 9. It becomes an open circuit for recirculation, and the TCS pump 9 can be operated in a no-load state.

[0012]

【Example】

 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 drive 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, 4 is a reservoir, and these are for each drive wheel from the master cylinder M to the reservoir 4. It is connected in series. The wheel cylinder of the brake B provided on the drive wheel is connected to the pipeline between the hold valve 2 and the decay valve 3, and the pipeline between the decay valve 3 and the reservoir 4 is connected to the pipeline. The suction port of the anti-skid hydraulic pump 5 is connected. Further, the discharge port of the anti-skid hydraulic pump 5 is connected to the conduit 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 which constitutes a TCS unit described later is connected to a pipe line between the cut valve 1 and the hold valve 2. The TCS unit comprises 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 the switching valve 10 and the 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 configuration of the switching valve 10 will be described based on FIG. The switching valve 10 is composed of a piston 21, a valve 22, and springs 23 and 24 housed in the valve body, and the piston 21 and the valve body form a liquid chamber 25. The liquid chamber 25 communicates with the master cylinder M. The piston 21 has a valve opening rod 26, a valve 22 is provided corresponding to this rod 26, and the piston moves to the right in the figure against the urging force of the spring 23. The valve 22 can be moved to the right to connect the flow paths 27 and 28.

Therefore, in the switching valve 10, in a state where no hydraulic pressure is generated in the master cylinder M, the flow passages 27 and 28 are blocked by the valve 22 as shown in the figure, and hydraulic pressure is generated in the master cylinder M. Then, 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, the discharge liquid from the TCS pump 9 becomes an open circuit that recirculates to the suction port of the TCS pump 9, resulting in no load condition Will be driving in.

The pressurizing piston 7 is for supplying brake fluid to the anti-skid hydraulic circuit by the action of the discharge brake hydraulic pressure from the TCS pump 9 during traction control. It is formed by dividing the room. One of the compartments is connected to the discharge port of the TCS pump through the liquid passage, and the other compartment is connected between the cut valve 1 and the hold valve 2 of the anti-skid hydraulic circuit through the liquid passage. A pressure spring 71 that constantly presses the pressure piston 9 to the left in the drawing is arranged in the other compartment. 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 has an accumulator spring that biases the piston to the left in the figure. 81 are arranged.

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

The TCS pump 9 is operated by a motor during traction control, and when the switching valve 10 is closed, hydraulic pressure is generated in the circuit. Further, the TCS pump is driven in conjunction with the anti-skid hydraulic pump 5 during ABS operation, but by keeping the switching valve 10 open, the brake fluid is accumulated in the accumulator 8 → TCS pump 9 → switching valve 10 → accumulator. 8 to circulate and generate no pressure in the circuit.

Next, the operation of the ABS / TCS modulator having the above configuration will be described. (1) During normal braking During normal braking, each switching valve is in the state shown in the figure. By depressing the brake pedal, hydraulic pressure is generated in the master cylinder M, and the brake hydraulic pressure generated here is supplied from the discharge port of the master cylinder M to the brake cylinder via the cut valve 1 and the hold valve 2, and the brake pressure is applied. Works.

(2) During anti-skid control When the wheel skid is detected by a wheel speed sensor (not shown) during braking, the electronic control circuit controls the hold valve 2, the decay valve 3 and the anti-skid valve according to the skid state of the wheel. The skid hydraulic pump 5 is controlled. When the signal for holding the brake is output, the hold valve 2 is closed, the fluid passage between the master cylinder and the wheel cylinder is cut off, and the brake fluid pressure in the wheel cylinder is held. When a brake release signal is output from an electronic control unit (not shown), the hold valve 2 is closed to shut off the fluid passage between the master cylinder and the wheel cylinder, and at the same time the decay valve 3 is opened to connect the wheel cylinder and the reservoir. The brake fluid in the wheel cylinder is discharged to the reservoir 4 through the fluid passage, and the brake is released.

Then, the brake fluid discharged to the reservoir 4 is recirculated to the master cylinder M by the antiskid hydraulic pump 5 that operates at the same time when the hydraulic pressure control is started. 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 driven by the motor 12 together with the anti-skid hydraulic pump 5, but the switching valve 10 in the circuit of the TCS pump 9 causes the passages 16 and 17 to flow through the flow passages 16 and 17 by the hydraulic pressure from the master cylinder. Since they are in communication, they are driven without load.

(2) Traction control When a vehicle speed is started, when a wheel speed sensor (not shown) detects that the driving torque of the driving wheel of the driving wheel is too large due to a sudden start and a slip larger than a predetermined value is detected, 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 pressurizing 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, the TCS pump 9 starts operating, and the TCS pump 9 sucks the brake fluid from the accumulator 8.

At this time, since the TCS pump 9 sucks the brake fluid (for example, 1 to 10 kg / cm ² ) having a high pressure from the accumulator, 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. By the rightward movement of the pressurizing piston 7, the brake fluid in the pressurizing piston is supplied to the brake cylinder via the hold valve 2. As a result, the drive wheels are braked and drive slip is reduced. Further, during this slip control, the hold valve 2 and the decay valve 3 are respectively controlled by the electronic control device, and the braking force holding, loosening and loading are repeated according to the slip state of each driving wheel.

As described above, the drive slip can be controlled to the optimum state. Then, when the drive slip is almost eliminated, the electronic control unit detects this and stops the drive of the TCS pump 9 and switches the cut valve 1 to the illustrated state. In this way, according to the present invention, while the anti-skid control is being executed, the TCS pump 9 becomes a no-load operation due to the open circuit through the switching valve 10, thus preventing the occurrence of conventional cavitation. I can do it.

Next, a second embodiment of the present invention will be described with reference to FIG. The cut valve 1 in the first embodiment is composed of an electromagnetic valve that switches the flow path with a signal from the ECU when the traction control is started, but in the present embodiment, the cut valve in the first embodiment is used. 1 and the pressurizing piston 7 are integrated so that the cut valve can be operated by hydraulic pressure. The pressurizing piston / cut valve 30 is composed of a piston 31, a valve 32, and a spring 37 housed in a valve body, and the piston 31 and the valve body form liquid chambers 33 and 36. The liquid chamber 33 communicates with the master cylinder M via a valve 32 and a flow passage 34, and also communicates with the hold valve 2 via a flow passage 35. Further, the liquid chamber 36 communicates with the discharge port of the TCS pump 9. The 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 connect the flow path 34 and the liquid chamber 33 in the state shown in the figure.

Therefore, in the pressurizing piston / cut valve 30, the hydraulic pressure from the TCS pump 9 is not generated at the time of non-traction control, so that the piston 31 is in the state shown in the drawing, and the hydraulic pressure generated in the master cylinder M is in the flow path. It is supplied to the brake cylinder through 34 → valve 32 → liquid chamber 33 → flow path 35. On the other hand, during traction control, the piston 31 moves to the right due to the hydraulic pressure generated by the TCS pump 9, and the valve 32 also moves to the right due to the spring 38, cutting 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 to the right, 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, since the cut valve and the pressurizing piston are integrally formed and the cut valve can be controlled by the hydraulic pressure as well, it is necessary to use the electromagnetic valve as in the conventional case. The cost can be reduced significantly.

[0029]

[Effect of the device]

 As described in detail above, according to the present invention, while the anti-skid control is being executed, the TCS pump is operated under no load by the open circuit, so that the conventional cavitation can be prevented. Furthermore, since the cut valve can also be controlled by hydraulic pressure, there is no need to use an electromagnetic valve as in the past, and the cost can be reduced. Therefore, it was possible to obtain an ABS / TCS modulator that is extremely safe and easy to manufacture.

[Brief description of 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 drive 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 driving wheels.

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

[Explanation 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 Cut valve that also serves as pressurizing piston

Claims (2)

[Scope of utility model registration request] 1. A hydraulic circuit for anti-skid, a hydraulic pump for anti-skid, which is provided in the circuit and acts to pump out a discharge liquid from a wheel cylinder during anti-skid control, and a hydraulic circuit for traction control. ,
Brake fluid is sucked from a low-pressure accumulator that is provided during the traction control and accumulates a predetermined fluid pressure only during traction control, and the brake fluid pressure can be applied to the wheel cylinder via the anti-skid hydraulic circuit by the discharge pressure. In an ABS / TCS modulator having a possible traction control hydraulic pump and a common motor for driving each of the pumps, a master is provided in a circuit connecting the suction passage and the discharge passage of the traction control hydraulic pump. An ABS / TCS modulator provided with a switching valve that opens the circuit by hydraulic pressure from a cylinder. 2. A hydraulic circuit for anti-skid, a hydraulic pump for anti-skid, which is provided in the circuit and acts to pump out liquid discharged from a wheel cylinder during anti-skid control, and a hydraulic circuit for traction control. ,
Brake fluid is sucked from a low-pressure accumulator that is provided during the traction control and accumulates a predetermined fluid pressure only during traction control, and the brake fluid pressure can be applied to the wheel cylinder via the anti-skid hydraulic circuit by the discharge pressure. In an ABS / TCS modulator having a possible traction control hydraulic pump and a common motor for driving each of the pumps, a fluid path communicating the antiskid hydraulic circuit and the traction control hydraulic circuit. During non-traction control, the master cylinder communicates with the hold valve, while during traction control the master cylinder and hold valve are disconnected, and hydraulic pressure is generated by the discharge pressure from the traction control hydraulic pump. A cut valve that also serves as a pressure piston is provided, and a switching valve that opens the circuit by the hydraulic pressure from the master cylinder is provided in the circuit that connects the suction passage and the discharge passage of the traction control hydraulic pump. ABS / TCS modulator characterized by: