JPS61211155A - Antiskid control unit - Google Patents

Abstract

PURPOSE:To allow compactness of a pump driving section by disconnecting a relief duct that bypasses a hydraulic pump and a duct between master and wheel cylinders, respectively, when the wheels are locked and opening a duct between the hydraulic pump and wheel cylinder. CONSTITUTION:Cut valves 101-104 are interposed in the first ducts (20-22 and 30-32) that connect the two pressure chambers of a master cylinder 3 to the right and left, rear and front and rear wheel cylinders 4-7 in an X- shaped form. In addition, a hydraulic motor 10 driven the exhaust oil of the hydraulic pump 12 of a power steering device and a bypass route 43 in which an ON and OFF valve 111 is interposed so as to bypass this motor 10. Hydraulic pumps 8 and 9 are driven by the hydraulic motor 10 and the exhaust oil of the pumps 8 and 9 is connected to wheel cylinders 4-7 through the second ducts (70-72 and 80-82) and switching valves 106-109. Besides, release pipes 73 and 83 in which control valves 201-202 are interposed are connected to the hydraulic pumps 8 and 9.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a braking system for a vehicle, and more particularly to an anti-skid control device that prevents wheels from locking during braking and impairing vehicle maneuverability. .

[Conventional technology]

A vehicle brake system is constructed by connecting a master cylinder connected to a brake pedal and a wheel cylinder provided in a wheel brake mechanism through a conduit. For example, the anti-skid control device is disclosed in Japanese Patent Publication No. 49-2830.
As described in Publication No. 7, a valve is provided in the middle of the pipe line to release pressure oil in the foil cylinder to the outside, and a pump is provided to feed the pressure oil into the foil cylinder. That is, when a wheel lock is detected, the pressure oil in the wheel cylinder is released rapidly, and then when the wheel needs to be braked again, the pump supplies pressure oil to the wheel cylinder relatively gradually.

[Problem that the invention seeks to solve]

Anti-skid control requires a certain amount of brake oil, but since the pumps installed in conventional anti-skid control devices are driven by electric motors, a fairly large pump is required to have a discharge flow rate above a certain value. It had to be something.

[Means for solving problems]

In order to solve the above problems, the present invention takes the following measures. In other words, there is a cut valve that selectively connects and shuts off the first pipe connecting the master cylinder and the wheel cylinder, a hydraulic motor that is rotationally driven by a hydraulic source that constantly generates pressure, and an upstream side of the hydraulic motor. a bypass passage connecting the downstream side, an on-off valve for blocking the bypass passage and guiding all the hydraulic pressure from the hydraulic power source to the hydraulic motor when the brake is applied, a hydraulic pump driven by the hydraulic motor, and a hydraulic pump driven by the hydraulic motor; A switching valve that switches and controls a second pipe line that connects the pump and the foil cylinder, a relief pipe that connects the upstream side and the downstream side of the hydraulic pump, and a control valve that opens and closes communication of the relief pipe line. and when the wheels are locked, the control valve cuts off the relief pipe, the cut valve cuts off the first pipe, and the switching valve switches the second pipe to close the wheel cylinder. The anti-skid control device is characterized in that the pressure oil of the hydraulic pump is supplied to the hydraulic pump, or the pressure oil in the foil cylinder is released to the outside.

[Effect]

During normal braking operation, pressure oil from the master cylinder is supplied to the wheel cylinder through the first conduit to perform the braking action. The hydraulic motor is driven to rotate each time the brake is applied, and the hydraulic pump is also driven. When the wheels lock, the control valve shuts off the relief line and the cut valve shuts off the first line. Then, depending on the locked state of the wheels, the switching valve switches the second pipe line to supply pressure oil from the hydraulic pump to the wheel cylinder or release the pressure oil in the wheel cylinder to the outside. Keep the wheel rotation speed appropriate.

〔Example〕

Next, embodiments of the present invention will be described based on the drawings.

FIG. 1 shows an embodiment of the invention. This embodiment is an example in which the present invention is applied to a so-called FF vehicle, and the piping system of the brake system has an X piping as is well known, and the same system is used for the wheel cylinder 4 of the right front wheel and the wheel cylinder 7 of the left rear wheel. Brake oil is supplied from the same pipe line, and brake oil is supplied to the wheel cylinder 5 of the left front wheel and the wheel cylinder 6 of the right rear wheel from the same pipe line. Brake pedal 1 is connected to master cylinder 3 via vacuum booster 2.
The hydraulic pressure generated in the master cylinder 3 when the brake pedal 1 is depressed is transmitted through a pipe to each wheel cylinder 4 of the right front wheel, left front wheel, right rear wheel, and left rear wheel, as described later. .5.6.7, and a braking action is performed. As is conventionally known, the vacuum booster 2 is guided by the negative pressure generated in the intake manifold of the engine.
In response to depression of the brake pedal 1, a push rod connected to a piston of a master cylinder 3 is energized to reduce the force of depression of the brake pedal by the driver.

The master cylinder 3 has two pressure chambers (not shown) that discharge brake oil of the same pressure, and supply pipes 20 and 30 are connected to each pressure chamber, respectively. The supply pipe 20 branches into brake pipes 2I and 22, the brake pipe 21 is connected to the wheel cylinder 5 of the left front wheel, and the brake pipe 22 is connected to the wheel cylinder 6 of the right rear wheel. Each of these brake pipes 21, 22 is provided with a cut valve 101, 102. The cut valves 101102 are both two-boat two-position valves, each communicating the brake pipes 21.22 in a first position shown, and blocking the brake pipes 21.22, respectively, in a second position different from that shown. Similarly, the supply pipe 30 is branched into brake pipes 31, 32, the brake pipe 31 being connected to the wheel cylinder 4 of the right front wheel, and the brake pipe 32 being connected to the wheel cylinder 7 of the left rear wheel.

Cut valves 103 and 104 are connected to brake pipes 31 and 3, respectively.
2 to selectively connect and cut off these pipes.

Each cut valve 101, 102, 103, 104 is switched from the first position to the second position in response to the discharge pressure of the hydraulic pump 8.9, as will be described later.

Brake pipe 2 connected to rear wheel wheel cylinder 6.7
2. In the middle of 32, a conventionally known probo-shinning valve 105 is provided, and when the oil pressure exceeds a certain value, brake oil at a pressure lower than the discharge pressure of the master cylinder 3 is supplied to the rear wheel wheel cylinder. 6.7.

With the above configuration, a normal braking action is performed, and at this time, the cut valves 101, 102, 103, and 104 are in the first position, and the hydraulic pressure generated in the master cylinder 3 when the brake pedal 1 is depressed is transferred to the supply pipe 20 and the brake tube 21
to the wheel cylinder 5 of the left front wheel via the supply pipe 20 and the brake pipe 22 to the wheel cylinder 6 of the right rear wheel via the supply pipe 30 and the brake pipe 31 to the wheel cylinder 4 of the right front wheel via the supply pipe 30 and the brake pipe 31. 30 and brake pipe 32 to the wheel cylinder 7 of the left rear wheel.

Next, a configuration for performing anti-skid control will be explained.

Pumps 8.9 are driven by hydraulic motors 10 and each have oil pipes 5 communicating with reservoirs 11, as will be explained in detail later.
0.60 branch pipe 59.69 and this oil is supplied to each wheel cylinder 4.0 through a supply pipe 70.80.
5.6.7.

The branch pipe 71 of the supply pipe 70 can communicate with the branch pipe 33 of the brake pipe 31 via the switching valve 106, and a check valve is provided in the middle of the branch pipe 71 to prevent brake fluid from flowing backward from the switching valve 106. 91 and an aperture 92 are provided. Switching valve 1
06 is a 3-point, 2-position valve, one discharge port is connected to the branch pipe 33, and the other discharge port is connected to the branch pipe 51 of the oil pipe 50. Thus, the switching valve 106 allows the branch pipe 71 to communicate with the branch pipe 33 in the first position shown in the figure, and connects the branch pipe 33 to the branch pipe 51 in a second position different from that shown in the figure.
communicate with. Therefore, when the switching valve 106 is in the first position, the brake fluid discharged from the pump 8 is transferred to the supply pipe 7.
When the switching valve 106 is in the second position, the brake fluid in the wheel cylinder 4 is supplied from the branch pipe 33 to the switching valve 106, when the switching valve 106 is in the second position. Reservoir 1 passes through branch pipe 51 and oil pipe 50
Released to 1.

Similarly, the branch pipe 72 of the supply pipe 70 can communicate with the branch pipe 34 of the brake pipe 32 via the switching valve 107.
A check valve 93 and a throttle 94 are provided. One discharge port of the switching valve 107 is connected to the branch pipe 34, and the other discharge port is connected to the branch pipe 52 of the oil pipe 50. Thus, when the switching valve 107 is in the first position shown in the figure, it connects the branch pipe 72 to the branch pipe 34 to guide the brake oil discharged from the pump 8 to the wheel cylinder 7, and is in a second position different from the one shown in the figure. The branch pipe 34 is communicated with the branch pipe 52 to release the brake oil in the wheel cylinder 7 to the reservoir 11.

The branch pipe 81 of the supply pipe 80 can communicate with the branch pipe 27 of the brake pipe 21 via the switching valve 108, and the branch pipe 81 is provided with a check valve 95 and a throttle 96. One discharge port of the switching valve 108 is connected to the branch pipe 27, and the other discharge port is connected to the branch pipe 61 of the oil pipe 60. Therefore, when the switching valve 108 is in the first position shown in the figure, the branch pipe 81 is communicated with the branch pipe 27 to guide the brake oil discharged from the pump 9 to the wheel cylinder 5, and when it is in the second position different from the one shown in the figure, When the branch pipe 27 is communicated with the branch pipe 61, the brake oil in the wheel cylinder 5 is released to the reservoir 11.

Similarly, the branch pipe 82 of the supply pipe 80 has a check valve 97 and a throttle 98, and is connected to the branch pipe 28.62 via a switching valve 109. Brake oil is introduced into the cylinder 6, and when the brake oil is in the second position, the brake oil in the wheel cylinder 6 is transferred to the reservoir 11.
release to.

The pumps 8 and 9 discharge the same amount of pressure oil, and are rotationally driven coaxially by the hydraulic motor 10. The hydraulic motor 10 is driven by being supplied with pressure oil by a pressure oil supply pump 12 of the power steering device. Therefore, the discharge port of the pump 12 and the suction port of the motor 10 are connected via the input pipe 41, and the output pipe 42 connected to the discharge port of the motor 10 is connected to the gear box 13 of the power steering device. . The input pipe 41 and the output pipe 42 are connected to each other by a bypass pipe 43, and this bypass pipe 43 communicates with each other through an on-off valve 111.
Be cut off. The pressure inside the master cylinder 3 is introduced to this on-off valve 111 via a conduit 16, and the bypass pipe 43 is communicated or disconnected according to this pressure. In other words, the on-off valve 111 is in an open state and conducts the bypass pipe 43 when the brake is not operated, and is closed when the brake is operated, that is, when the pressure inside the master cylinder 3 is increased by depressing the pedal 1. to shut off the bypass pipe 43.

The pressure oil supply pump 12 sucks oil from the reservoir 14 through the suction pipe 44, and when the on-off valve 111 is in the open state, pumps pressure oil through the input pipe 41, bypass pipe 43, and output pipe 42. Supplied to gearbox 13. Therefore, no differential pressure is generated in this hydraulic motor 10, and the hydraulic motor 10 is stopped.

On the other hand, when the on-off valve 111 is in the closed state, the pressure oil supply pump 12 supplies pressure oil to the hydraulic motor 1 via the input pipe 41.
Pressure oil is supplied to the gear box 13 via the output pipe 42. The pressure oil supply pump 12 is constantly driven while the vehicle is driving.
When the brake is operated, the on-off valve 111 closes, pressure oil is immediately supplied to the motor 10, and the pump 8.9 is started. Note that the oil used in the gearbox 13 is returned to the reservoir 14 through the discharge pipe 45.

The suction side and the discharge side of the pump 8.9 are connected by relief pipes 73.83, respectively.
A relief valve 109 and an electromagnetic control valve 201 are provided in parallel in the relief pipe 83, and a relief valve 110 and an electromagnetic control valve 202 are provided in parallel in the relief pipe 83. These relief valves 109, 110 respectively supply the pressure in the pipes 30, 20 via the conduits 15, 16 to the pressure in the master cylinder 3.
The pressure inside the relief tube 73. is guided, and the relief tube 73.
83 to control the discharge pressure of the pump 8.9. That is, when the discharge pressure of the pump 8.9 becomes greater than the pressure inside the master cylinder 3, the relief valve 109.110
is opened so that the pressure is substantially equal to the discharge pressure of the pump 8.9.

Further, the electromagnetic control valves 201 and 202 are in the first position shown in the figure during normal times when anti-skid control is not performed, and communicate with the relief pipes 73 and 83. Then, during anti-skid control, it switches to a second position different from that shown in the figure.
Communication between relief pipes 73 and 83 is cut off. The electromagnetic control valves 201 and 202 are driven to open and close in response to commands from an electric control unit (ECU), not shown.

The discharge pressure of the pump 8 acts on cut valves 103, 104 via a transmission pipe 74 communicating with the supply pipe 70, and the discharge pressure of the pump 9 acts on the cut valves 103, 104 via a transmission pipe 84 communicating with the supply pipe 80.
act on the cut valves 101, 102 via. The cut valves 101102, 103, and 104 are spool-type valves, and when the hydraulic pressure derived from the pump 8.9 exceeds a certain value, they are displaced against the elastic force of the spring and switched from the first position to the second position. However, when the oil pressure is below a certain value, the spring returns from the second position to the first position by the elastic force of the spring.

Anti-skid control is executed when it is determined that any of the wheels is locked, in other words, when it is determined that the deceleration or slip rate of the wheels is too large. The deceleration and slip rate of the wheels are calculated by an electric control unit (ECU) (not shown) equipped with a microcomputer, and therefore a vehicle speed sensor (not shown) is provided near the wheels. When the ECU determines to start anti-skid control, the control valve 201.
202 from the first position to the second position, and then the switching valve 106 is switched in accordance with the deceleration and slip rate of the wheels.
．． Switch 107.108.109. Note that the rear wheel switching valves 107 and 109 are always switched to the same position.

The operation of the apparatus of this embodiment will be explained using FIGS. 2(a), (b), and (C).

In the non-actuated state, when no braking is applied, the cut-off valves 101, 102, 103, 104 are each in a first position. Therefore, when the brake pedal 1 is depressed, the pressure oil discharged from the master cylinder 3 passes through the brake pipe 31.2L22.32 to each wheel cylinder 4.5.
．． 6.7, the pressure inside these foil cylinders increases rapidly. That is, when the brake pedal 1 is depressed at time To, the pressure P in the wheel cylinder rapidly increases, and the wheel speed Vw accordingly decreases rapidly from time T1. On the other hand, the speed Vv of the vehicle body also begins to decrease from time T, but the decrease in the speed Vw of the wheels is more rapid.

In such a brake operating state, when the pressure Pm in the master cylinder reaches the set pressure Po (the time at this time is T), the on-off valve 111 switches from the open state to the closed state, and the pressure All pressure oil discharged from the oil supply pump 12 is supplied to the hydraulic motor 10. Then, the hydraulic motor 10 is started in response to the supply of this pressure oil, and the pump 8.9, which is rotationally driven by the hydraulic motor 10, is rotated for a time T.

Start rotating at .

When the wheel speed Vw becomes smaller than the reference speed v1 shown by the broken line in FIG. At T2, the solenoid of the control valve 201, 202 is energized and the control valve 201, 202 is switched to the second position, so that the relief pipe 73
．． Block 83. As a result, the pressure oil is transferred to the cart/cart valve 10 via the transmission pipe 74.84 until the pump 8.9 discharges the oil.
1.102.103.104, whereby the cut-off valve 101.102.103.104 is switched to the second position and at time T, the brake pipe 21.22.3
1.32 is blocked.

When switching of the cut valve is completed at time T3, at the same time, in order to reduce the pressure in a predetermined foil cylinder, the switching valve 106, 107, 108, 109 corresponding to that foil cylinder is switched to the second position. The brake oil in this foil cylinder is released into the reservoir 11 through the oil pipe 50 or the oil pipe 60. The pressure within the foil cylinder therefore begins to decrease from time T3.

On the other hand, when the deceleration of the wheels decreases and it becomes necessary to increase the pressure in the wheel cylinder again, the switching valve is switched to the first position at time T4 in the figure. As a result, branch pipes 71, 72, 8 with large flow resistance are connected to the foil cylinder.
Brake oil is gradually supplied through 1.82, and the wheel cylinder pressure increases relatively slowly.

Thereafter, each switching valve 106, 107, 108, 109 is switched according to the deceleration or slip rate of the wheels, and the pressure in the wheel cylinder 4.5.6.7 is rapidly decreased or gradually increased. The anti-skid control ends when the vehicle stops or the brake switch is turned OFF, and at this time the control valves 201 and 202 are switched to the first position by the ECU and the oil discharged from the pump 8.9 is transferred to the relief pipe 73 and 83. Provides relief. As a result, the pressure in the transmission tube 74.84 decreases and the cut valve 101.102.103.104 is returned to the first position by the spring. Further, when the brake operation is completed and the pressure in the master cylinder 3 falls below the set pressure PO, the on-off valve Ill changes from the closed state to the open state, and all the pressure oil discharged from the pressure oil supply pump I2 is transferred to the bypass pipe 43. flows, and the hydraulic motor 10 stops. As a result, the pump 8.9, which was coaxially rotationally driven by the hydraulic motor 10, also stops.

In the above-described anti-skid control, the brake pedal is depressed at time TO, and after the master cylinder pressure reaches the set pressure at time T5 and the on-off valve 111 changes from the open state to the open state, the pump 8.9 is turned off at time T6. Start rotating. Then, at time Tz, the control valve 201
．． 202 has been switched, the pump 8.9 increases the discharge pressure and at time T, the cut valves 101.102.
Sufficient discharge pressure will be exerted to switch 103 and 104. Therefore, the time T at which the foil cylinder pressure starts to decrease can be made sufficiently early. Further, the hydraulic motor 10 that drives the pump 8.9 is supplied with pressure oil by the pump 12 of the power steering device, so the pump 8.9 is supplied with pressure oil by the pump 12 of the power steering device.
9 can be driven as long as the vehicle is being driven. Since the pump 8.9 is driven by the hydraulic motor 10 which is driven by the pump 12, it can be made smaller than a conventional structure driven by an electric motor.

Although the embodiment described above is a brake system for a front-wheel drive vehicle, the present invention is of course applicable to a front-wheel drive vehicle.

FIG. 3 is a hydraulic circuit diagram showing a second embodiment of the present invention.

In the first embodiment described above, the cut valve 101.102.10
3.104 are assumed to be opened and closed by hydraulic signals, but in this embodiment, electromagnetic cut valves 101a, 102a, 103a, 104a are opened and closed by electric signals from EUC etc.
is used. The other configurations and operations are completely the same as in the first embodiment.

Further, in the first and second embodiments, the on-off valve 111 is a hydraulic valve operated by brake oil pressure, but it may also be a solenoid valve or a piezo valve.

〔Effect of the invention〕

As described above, according to the present invention, the driving part of the pump, which is the supply source of brake fluid during anti-skid control, can be made smaller and the responsiveness of the system can be improved. It will be done.

[Brief explanation of the drawing]

Fig. 1 is a hydraulic circuit diagram showing the first embodiment of the present invention, Fig. 2 (al is a graph showing changes in vehicle speed and wheel speed, Fig. 2 (b) is a graph showing changes in wheel cylinder pressure, Second
Figure (C1 is a graph showing changes in pump discharge pressure, 3rd
The figure is a hydraulic circuit diagram showing a second embodiment. 3... Master cylinder, 4, 5, 6.7... Wheel cylinder, 8.9... Hydraulic pump, 10... Hydraulic motor, 20, 21, 22, 30, 31.32... 1st
Conduit,? 0,71.72,80,81.82...Second pipe line, 101,102,103.104...Cut valve, 106,107,108.109...Switching valve,
Ill...Opening/closing valve, 201, 202...Control valve. Representative Patent Attorney Takashi Okabe Figure 2

Claims (1)

[Claims] A cut valve that selectively connects and shuts off a first pipe connecting the master cylinder and the wheel cylinder, a hydraulic motor that is rotationally driven by a hydraulic source that constantly generates pressure, and an upstream and downstream side of the hydraulic motor. a bypass passage connecting the hydraulic motor, an on-off valve for blocking the bypass passage and guiding all the hydraulic pressure from the hydraulic power source to the hydraulic motor when the brake is applied, a hydraulic pump driven by the hydraulic motor, and the hydraulic pump. A switching valve that switches and controls a second pipe line connecting between the foil cylinders, a relief pipe that connects the upstream side and the downstream side of the hydraulic pump, and a control valve that opens and closes communication of the relief pipe line. When the wheels are locked, the control valve cuts off the relief pipe, the cut valve cuts off the first pipe, and the switching valve switches the second pipe to supply the wheel cylinder with the relief pipe. Supplying pressure oil for hydraulic pumps,
Alternatively, an anti-skid control device characterized in that the pressure oil in the foil cylinder is released to the outside.