JPH07125623A - Device for controlling acceleration slip - Google Patents

Abstract

PURPOSE:To prevent generation of damages of a pedal shock or a rubber seal of a master cylinder when the braking operation is executed while an acceleration slip control device is controlled. CONSTITUTION:The communication of a master cylinder 12 with front wheel cylinders 18, 32 is shut off by an electromagnetic direction switching valve 80, an electromagnetic opening/closing valve 132 is opened to feed the brake fluid from a master cylinder reservoir 84 to the front wheel cylinders 18,32 by a pump 66, and suppress the excessive slip in accelerating right and left front wheels 16, 30. An electromagnetic opening/closing valve 90 is opened according to the step-in quantity of a brake pedal 10, and the brake fluid is discharged through a pilot type opening/closing valve 92 until the wheel cylinder pressure becomes approximately equal to the master cylinder pressure. Then, an electromagnetic direction switching valve 80 is communicated with the master cylinder 12 and the front wheel cylinders 18, 32. The excessive brake fluid is already discharged, and no brake fluid flows into a pressurizing chamber, and no damages of the pedal shock and the rubber seal are generated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an acceleration slip control device and, more particularly, to processing at the end of acceleration slip control.

[0002]

2. Description of the Related Art Acceleration slip control is performed to prevent excessive slippage of driving wheels during vehicle acceleration. Therefore, the acceleration slip control device includes a device that reduces the slip by suppressing the rotation of the drive wheels by the brake. This brake is operated by transmitting the brake fluid pressure generated in the master cylinder to the wheel cylinder in response to the operation of the brake operating member, and during acceleration slip control, the brake operating member is operated by the wheel cylinder. A brake fluid pressure different from the brake fluid pressure due to is transmitted, and rotation of the drive wheels is suppressed.

The acceleration slip control device described in Japanese Utility Model Laid-Open No. 3-73255 is an example thereof. This acceleration slip control device is supposed to perform control using an antilock actuator for antilock control that suppresses excessive slip of the wheels during braking. The anti-lock actuator has two solenoid on-off valves, a pump and a reservoir provided in a liquid passage connecting the master cylinder and the wheel cylinder, and has a combination of two solenoid on-off valves to open and close the wheel cylinder. Fluid pressure increases, decreases,
The brake fluid, which is retained and discharged from the wheel cylinder to the reservoir, is returned by the pump to a portion of the fluid passage between the electromagnetic on-off valve and the master cylinder.

A further electromagnetic opening / closing valve is provided in a portion of the fluid passage on the master cylinder side of the portion where the brake fluid is returned, so that communication between the master cylinder and the wheel cylinder is cut off during acceleration slip control. There is. During acceleration slip control, the pump pumps the brake fluid from the reservoir of the master cylinder and supplies it to the wheel cylinder, and the hydraulic pressure in the wheel cylinder increases, decreases, and is maintained by opening and closing two electromagnetic on-off valves, and the drive wheel becomes excessive. Slippage is suppressed.

[0005]

In this type of acceleration slip control device, the wheel cylinder and the master cylinder are shut off by the shut-off valve such as the electromagnetic opening / closing valve during the acceleration slip control, but the acceleration slip control is completed. Then, the shutoff by the shutoff valve is immediately released, the wheel cylinder and the master cylinder are made to communicate with each other, and the brake fluid in the wheel cylinder is returned to the reservoir through the pressurizing chamber of the master cylinder. Therefore, when the brake operation is performed during the acceleration slip control, a shock may be generated in the brake operation member or the rubber seal of the pressurizing piston may be damaged.

If the brake operation is performed during the acceleration slip control, the acceleration slip control is terminated and the shutoff by the shutoff valve is released. In this case, the pressurization piston of the master cylinder is advanced by the brake operation. During this, the brake fluid flows back from the wheel cylinder into the master cylinder and pushes back the pressurizing piston, which causes a shock to the brake operating member and gives a driver discomfort.

Further, a port is formed in the cylinder bore of the master cylinder, and normally, the pressurizing chamber of the master cylinder and the reservoir are made to communicate with each other by the port, the pressurizing piston moves slightly forward, and the rubber seal of the pressurizing piston. In a master cylinder with a port in which the pressurizing chamber can be pressurized after the cup seal has passed through this port, the cup seal is pushed into the port by the backflowing brake fluid. It is damaged by being advanced with the pressure piston.

On the other hand, in the portless master cylinder in which the reservoir and the pressurizing chamber are communicated with each other by the liquid passage provided in the pressurizing piston, a check valve is provided in the liquid passage and is closed by advancing the pressurizing piston. The brake fluid in the pressurizing chamber is pressurized, but the rubber seal of this check valve is damaged. For example, as a valve of a check valve, a metal valve body covered with a rubber seal is widely used, and when brake fluid rapidly flows back from the wheel cylinder, this brake fluid reverses. When it flows out to the reservoir through the stop valve, the rubber seal is bent and pushed between the valve body and the valve seat. Then, when the liquid pressure in the pressurizing chamber becomes high, the pushed rubber seal is strongly sandwiched between the valve body and the valve seat and damaged. The check valve has a double structure having a rubber seal and a ball seal,
If the ball is seated on the valve seat before the rubber seal to block the communication between the reservoir and the pressurization chamber, when the brake fluid flows into the pressurization chamber, the seat of the ball seal on the valve seat causes the rubber seal Deflection is prevented and damage is avoided, but the structure of the master cylinder is inevitable.

In view of the above-mentioned circumstances, the present invention has a structure of a check valve for preventing a shock to a brake operating member and damage to a rubber seal of a master cylinder when a brake is operated during acceleration slip control. The object is to obtain an acceleration slip control device that can be avoided without complicating the above.

[0010]

In order to solve the above problems, the present invention operates by transmitting a brake fluid pressure generated in a master cylinder in response to an operation of a brake operating member to a wheel cylinder. Acceleration slip control device that shuts off the brake from the master cylinder with a shut-off valve and operates with a hydraulic pressure of a hydraulic pressure source different from that of the master cylinder in order to prevent excessive slippage of the drive wheels during vehicle acceleration. In the above, when the brake operation member is operated during the acceleration slip control, the hydraulic pressure lowering means for lowering the hydraulic pressure of the wheel cylinder, and the hydraulic pressure lowering means causes the hydraulic pressure of the wheel cylinder to be the same as that of the master cylinder. Provided with a shutoff release means for releasing the shutoff between the master cylinder and the brake by the shutoff valve after being lowered to almost the same level. Those were.

[0011]

As described above, after the hydraulic pressure of the wheel cylinder is reduced by the hydraulic pressure lowering means and the hydraulic pressure of the wheel cylinder becomes substantially equal to the hydraulic pressure of the master cylinder, the wheel cylinder and the master cylinder are made to communicate with each other. For example, the brake fluid in the wheel cylinders may not flow into the pressurizing chamber of the master cylinder, or the amount of inflow may be small, causing shock to the brake operating member and damaging the rubber seal of the pressurizing piston. Is avoided.

[0012]

As described above, according to the present invention, even if a large amount of brake fluid exists in the wheel cylinders at the end of the acceleration slip control, it is possible to prevent the brake fluid from flowing into the master cylinder.
It is possible to prevent a shock from occurring in the brake operating member and damage to the rubber seal of the pressure piston. Also,
The check valve of the master cylinder does not have to have a double structure having a rubber seal and a ball seal, and the structure of the master cylinder does not become complicated. In this case, the cutoff releasing means can be configured by a slight modification of the control program of the acceleration slip control device, and the hydraulic pressure lowering means can also be configured by a slight modification of the control program if the hydraulic pressure control device of the acceleration slip control device is used. In particular, the objective can be achieved at low cost.

[0013]

Embodiments of the present invention will now be described in detail with reference to the drawings. In FIG. 1, 10 is a brake pedal. The hydraulic pressure generated in one of the two pressurizing chambers of the master cylinder 12 by depressing the brake pedal 10 is transmitted to the front wheel cylinder 18 of the left front wheel 16 by the liquid passage 14. , Liquid passage 20
By the rear wheel cylinder 2 of the brake of the right rear wheel 22
4 via a proportioning valve 26. Further, the hydraulic pressure generated in the other pressurizing chamber is transmitted to the front wheel cylinder 32 of the brake of the right front wheel 30 via the liquid passage 28, and is transmitted to the left rear wheel 3 via the liquid passage 34.
It is transmitted to the rear wheel cylinder 38 of the No. 6 brake via the proportioning valve 40. The left and right front wheels 16 and 30 are drive wheels.

Left and right front wheels 16, 30 and rear wheels 36, 2
2 is independently antilock-controlled. The anti-lock control devices provided in each of the four wheels have the same configuration, and the left front wheel 16 will be representatively described. A normally open first electromagnetic opening / closing valve 50 is provided in the liquid passage 14, and a reservoir 54 forms a reservoir 54 in a portion of the liquid passage 14 between the first electromagnetic opening / closing valve 50 and the front wheel cylinder 18. It is connected.

A normally closed second electromagnetic on-off valve 56 is provided in the reservoir passage 52, and the combination of the opening and closing of the first and second electromagnetic on-off valves 50 and 56 causes the hydraulic pressure of the front wheel cylinder 18 ( (Hereinafter, referred to as wheel cylinder pressure) is increased by transmission of hydraulic pressure from the pressurizing chamber of the master cylinder 12 and is decreased by discharge of brake fluid to the reservoir 54, or the front wheel cylinder 18 is set to the master cylinder 12 The same height is maintained by blocking the communication with both the reservoir 54 and the reservoir 54.

The liquid passage 14 has a first electromagnetic opening / closing valve 50.
A bypass valve 58 for bypassing the valve is provided and a check valve 60 is provided so that the brake fluid quickly returns to the master cylinder 12 when the brake is released.

The brake fluid discharged from the front wheel cylinder 18 to the reservoir 54 is pumped up by a pump 66 equipped with two check valves 64 being driven by a pump motor 68, and the first electromagnetic fluid in the fluid passage 14 is pumped. It is returned to the part on the master cylinder 12 side from the opening / closing valve 50. 7
Reference numeral 0 is a shock absorber that absorbs the pulsation of the brake fluid. The pump 66 is provided with a relief valve (not shown),
The discharge pressure is set so as not to exceed the set value.

The left and right front wheels 16 and 30, which are the driving wheels, are respectively the first and second electromagnetic on-off valves 50 and 56, the reservoir 54,
Acceleration slip control is independently performed using the pump 66. Therefore, an electromagnetic directional control valve 80 is provided in each of the liquid passages 14 and 28. The electromagnetic directional control valve 80 is connected to the master cylinder reservoir 84 of the master cylinder 12 by a master cylinder reservoir passage 82, and a state in which the front wheel cylinders 18 and 32 are communicated with the pressurizing chamber of the master cylinder 12 and the master cylinder reservoir 84. It is switched to the state of communicating with. In the latter state, the front wheel cylinders 18, 32 and the pressurizing chamber of the master cylinder 12 are shut off, and the electromagnetic directional control valve 80 functions as a shutoff valve. Liquid passage 1
4, 28 are also provided with a bypass passage 86 that bypasses the electromagnetic directional control valve 80, and allows the flow of brake fluid from the master cylinder 12 to the front wheel cylinders 18, 32, but blocks the reverse flow. A check valve 88 is provided.

In the master cylinder reservoir passage 82, an electromagnetic opening / closing valve 90 for acceleration slip control and a pilot type opening / closing valve 92 are provided in series. The pilot-type on-off valve 92 is provided between the master cylinder reservoir 84 and the acceleration slip control electromagnetic on-off valve 90, and as shown in FIG.
98 are formed concentrically. The liquid chamber 96 is connected to the master cylinder 12 and houses the rod 102 sealed by the seal member 100. Rod 1
One end of 02 is slidably projected into the liquid chamber 98, and a large-diameter spring receiver 104 is brought into contact with the projecting end.

The liquid chamber 98 has a master cylinder reservoir 84.
And a valve seat member 108 having a circular cross section. A valve seat 110 is formed at the protruding end of the valve seat member 108 into the liquid chamber 98, and a liquid passage 112 that opens to the valve seat 110 and is connected to the front wheel cylinders 18 and 32 is formed in the valve seat member 108. Are formed. A spring receiver 114 is also accommodated in the liquid chamber 98 so as to be movable in the axial direction. The spring receiver 114 holds a ball 116 as a valve element, and a spring 118 arranged between the spring receiver 114 and the spring receiver 104 causes the ball 11 to move.
6 is urged in such a direction as to be seated on the valve seat 110. The effective pressure receiving area of the ball 116 when seated on the valve seat 110 is made slightly smaller than the effective pressure receiving area of the rod 102. If the front wheel cylinder pressure of the liquid passage 112 does not become slightly higher than the master cylinder pressure, the pilot type The on-off valve 92 does not open.

When the hydraulic pressure is not supplied from any of the front wheel cylinders 18 and 32 and the master cylinder 12, the rod 102, the spring bearing 104 and the spring bearing 114 are in the positions shown in the drawing, and the rod 102 and the spring bearing 114 are not separated from each other. Ball 1 with small distance
16 sits on the valve seat 110 to block the communication between the front wheel cylinders 18, 32 and the master cylinder reservoir 84.

Further, the master cylinder reservoir 84 is
The fluid passage 130 is connected between the check valve 64 of the pump 66 for pumping up the brake fluid discharged to the reservoir 54 and the reservoir 54. A normally closed brake fluid supply electromagnetic on-off valve 132 is provided in the fluid passage 130, and the pump 66 is operated while the brake fluid supply electromagnetic on-off valve 132 is open. The brake fluid is supplied from the electromagnetic direction switching valve 80 of the fluid passage 28 to the portion on the front wheel cylinder 32 side. The check valve 134 blocks the brake fluid pumped from the master cylinder reservoir 84 into the reservoir 54.

The acceleration slip control is carried out by an acceleration slip control unit 140 mainly composed of a computer. The rotation speeds of the left and right front wheels 16, 30 and the rear wheels 36, 22 are measured by the rotation speed sensors 142, 144, 146, 1
It is detected by 48 and supplied to the vehicle speed calculation unit 150. The vehicle speed and the like calculation unit 150 calculates the wheel speed, the wheel acceleration, the vehicle body speed and the like, and supplies them to the acceleration slip control unit 140 and an antilock control unit (not shown).

The anti-lock control unit includes the first and second electromagnetic on-off valves 50 and 52 of each system of four wheels, the pump motor 6
8 is controlled to perform anti-lock control. On the other hand, the acceleration slip control unit 140 is connected with a brake switch 152 for detecting the depression of the brake pedal 10, and the first and second electromagnetic on-off valves 50, 56 of the left and right front wheel systems are connected.
Electromagnetic directional control valve 80, electromagnetic on-off valve for acceleration slip control 9
0, opening / closing and switching of the brake fluid supply electromagnetic on-off valve 132, and controlling the pump motor 68 to perform acceleration slip control. In the RAM of the computer of the acceleration slip control unit 140, as shown in FIG.
4 and a flag 156 are provided together with the working area, and various programs necessary for performing the acceleration slip control are stored in the ROM, the hydraulic pressure counting routine shown in the row chart of FIG. 4 and the acceleration slip control end processing shown in FIG. Contains routines.

Next, the operation will be described. During non-braking and non-driving, the first and second electromagnetic on-off valves 50 and 56, the electromagnetic directional control valve 80, the acceleration-slip control electromagnetic on-off valve 90, and the brake fluid supply electromagnetic on-off valve 132 are positioned as shown in FIG. The hydraulic pressure of the master cylinder 12 (hereinafter referred to as the master cylinder pressure) is supplied to the front and rear wheel cylinders 18, 32, 24, 38. Therefore, when the brake pedal 10 is depressed, the master cylinder pressure is transmitted to the front and rear wheel cylinders 18, 32, 24, 38, and the left and right front wheels 16, 30 and the rear wheels 22, 36 are prevented from rotating. .

When the braking force is excessive with respect to the friction coefficient of the road surface and the slip ratio of the wheels exceeds the proper range, antilock control is performed. First and second solenoid on-off valves 50,
By opening and closing 56, the wheel cylinder pressure is increased, decreased, and held, and the slip ratio of the wheel is kept within an appropriate range.

Further, when the driving force at the time of acceleration such as starting the vehicle is excessive with respect to the friction coefficient of the road surface and the slip ratios of the left and right front wheels 16 and 30 which are the driving wheels become excessive, the acceleration slip control is performed. Is done. In this case, the electromagnetic directional control valve 80 is switched and the front wheel cylinder 1
The 8 and 32 are communicated with each other and the communication with the master cylinder 12 is blocked. The electromagnetic on-off valve 90 for acceleration slip control is kept closed, the electromagnetic on-off valve 132 for supplying brake fluid is opened, and the pump 66 is opened.
Is driven. Therefore, the master cylinder reservoir 84
The brake fluid in the inside is pumped up and supplied to the front wheel cylinders 18, 32, the respective rotations of the left and right front wheels 16, 30 are suppressed, and the slip is reduced. The master cylinder reservoir 84 and the pump 66 constitute a hydraulic pressure source for acceleration slip control, and the pump 66 for antilock control is used.
Is also used as a hydraulic pressure source for acceleration control.

The hydraulic pressure in the front wheel cylinders 18 and 32 is controlled by opening and closing the first and second solenoid on-off valves 50 and 56.
The slip ratio is increased, decreased, and maintained so that it is within the appropriate range. At this time, the front wheel cylinder 1
The brake fluid discharged from 8, 32 to the reservoir 54 is
It is returned to the liquid passages 14 and 28 by the pump 66.

When the acceleration slip control is performed in this manner, the hydraulic pressure counting routine and the acceleration slip control end processing routine are executed. The hydraulic pressure counting routine is performed separately for the front wheel cylinders 18 and 32.
Will be representatively described.

In the hydraulic pressure counting routine, first, in step S1 (hereinafter abbreviated as S1. The same applies to other steps), it is determined whether or not the acceleration slip control is being performed. If the acceleration slip control is not performed, the determination result is NO, S8 is executed,
Whether or not the acceleration slip control ending process is being performed is determined depending on whether or not the flag 156 is ON. If the acceleration slip control end process is not performed, the determination result in S8 is NO, the counter 154 is reset in S9, and the execution of the routine ends.

If the acceleration slip control is being performed, the determination result in S1 is YES, and in S2 it is determined whether or not the wheel cylinder pressure is maintained. If it is, the determination result in S2 is YES. Then, the execution of the routine ends. If the wheel cylinder pressure is not held, S3 is executed and it is determined whether or not the wheel cylinder pressure is increased. If the pressure is increased, the determination result of S3 is YES, S4 is executed, and the count value C of the counter 154 is increased by α. α will be described later.

If the wheel cylinder pressure has been reduced, the determination result in S3 becomes NO, S5 is executed, and the count value C is reduced by β. The amount of brake fluid supplied to the front wheel cylinder 18 when the pressure is increased in the acceleration slip control and the amount of brake fluid discharged from the front wheel cylinder 18 to the reservoir 54 when the pressure is reduced are respectively
Discharge capacity of pump 66, first and second solenoid on-off valves 50, 5
The amount of supply and the amount of discharge are not the same, depending on the structure of 6 and so on. The α and β are respectively the front wheel cylinders 18, 3 while the program is executed for one cycle.
2 is a value representing the ratio of the amount of brake fluid supplied to the front wheel cylinder 18 and the amount of brake fluid discharged from the front wheel cylinder 18. The count value C obtained by such addition and subtraction of α and β is the front wheel. It represents the amount of brake fluid in the cylinder 18.

Next, in S6, it is judged whether or not the count value C is 0 or less. If it is not 0 or less, S7 is executed.
Is skipped and the execution of the routine ends. If it is 0 or less, S7 is executed and the count value C is reset, and the execution of the routine ends. The count value C is prevented from becoming a negative value. When there is no brake fluid left in the front wheel cylinder 18, the count value C =
This is because it is represented by 0.

In the acceleration slip control termination processing routine, it is determined in S101 whether the acceleration slip control is terminated. This judgment is based on the brake pedal 1
This is performed depending on whether 0 is depressed, whether the vehicle body speed is equal to or higher than a set value, or the like. If none of the acceleration slip control termination conditions are satisfied, the determination result in S101 is NO, and the routine execution is terminated.

If any one of the conditions for ending the acceleration slip control is satisfied, the determination result in S101 is YES.
Here, it is assumed that the brake pedal 10 is suddenly depressed. As a result, S102 is executed, the brake fluid supply electromagnetic on-off valve 132 is closed, and the supply of brake fluid from the master cylinder reservoir 84 is cut off. Further, the first and second electromagnetic on-off valves 50 and 56 are brought into the state shown in FIG. 1 and the front wheel cylinder 18 is brought into a pressure increasing state.
Further, the electromagnetic valve 90 for acceleration slip control is opened to bring the front wheel cylinder 18 into communication with the master cylinder reservoir 84, and the flag 156 is set.
Is set.

Although the electromagnetic directional control valve 80 remains switched to the state in which the front wheel cylinder 18 is shut off from the master cylinder 12, the hydraulic pressure generated in the pressurizing chamber of the master cylinder 12 by depressing the brake pedal 10 remains. Can be transmitted to the front wheel cylinder 18 through the bypass passage 86.

Due to the supply of brake fluid from the master cylinder reservoir 84 during acceleration slip control, there is pressurized brake fluid in the front wheel cylinder 18. Therefore, when the brake pedal 10 is initially depressed,
The wheel cylinder pressure is higher than the master cylinder pressure,
In the pilot type on-off valve 92, the rod 102 does not move forward, the ball 116 is separated from the valve seat 110, and the front wheel cylinder 18 and the master cylinder reservoir 8
4 is communicated with and the brake fluid is discharged. Also,
The brake fluid in the reservoir 54 is also pumped up by the pump 66 and discharged. From the master cylinder reservoir 84 to the front wheel cylinder 1 for acceleration slip control.
The brake fluid supplied to No. 8 is discharged.

When the master cylinder pressure increases and becomes slightly higher than the wheel cylinder pressure, the rod 102 is advanced and abuts the spring bearing 114 via the spring bearing 104,
The ball 116 is seated on the valve seat 110 to cut off the communication between the front wheel cylinder 18 and the master cylinder reservoir 84. After the shutoff, the hydraulic pressure slightly higher than the master cylinder pressure becomes the valve opening pressure, the pilot type on-off valve 92 does not open, the brake fluid supplied from the master cylinder 12 is not discharged to the master cylinder reservoir 84, and the front wheel cylinder The rotation of the wheels can be suppressed by being supplied to 18. When the master cylinder pressure and the wheel cylinder pressure are almost equal (more precisely, the wheel cylinder pressure is slightly higher than the master cylinder pressure), the reduction of the wheel cylinder pressure is ended, and the extra brake fluid is discharged. Never be done.

When the pilot type on-off valve 92 is open and the brake fluid in the front wheel cylinder 18 is discharged to the master cylinder reservoir 84, the wheel cylinder pressure is higher than the master cylinder pressure, and the wheel cylinder pressure causes the wheels to rotate. Sufficient to suppress. While the brake fluid supplied for the acceleration slip control is discharged to the master cylinder reservoir 84, the rotation of the wheels is suppressed, and after the discharge is completed, the master cylinder pressure passes through the bypass passage 86 to the front wheel cylinder 18. The rotation of the wheels is suppressed by being transmitted.

After the process at the end of the acceleration slip control such as closing the brake fluid supply electromagnetic on-off valve 132 is performed in S102, S103 is executed to determine whether the count value C of the counter 154 is 0 or not. Is done. This determination result is initially NO, and S105 is executed, and the value γ is subtracted from the count value C. This value γ represents the amount of brake fluid discharged to the master cylinder reservoir 84 during one cycle of execution of the program, as a ratio to the amount of brake fluid supplied and the amount of brake fluid respectively represented by the values α and β. This is a value, and subtracting the value γ from the count value C means measuring the time required to completely discharge the brake fluid amount in the front wheel cylinder 18 at the end of the acceleration slip control.

Next, S106 is executed, and the count value C
Whether or not is negative is determined, but the result of this determination is NO, and the execution of the routine ends. S101-S
If 103, S105, and S106 are repeatedly executed and the count value C becomes negative, the determination result of S106 becomes YES, and the count value C is reset in S107.
Therefore, when S103 is executed next time, the determination result is YES, S104 is executed, and the flag 156 is executed.
Is reset, and the electromagnetic directional control valve 80 is switched to a state in which the front wheel cylinder 18 and the master cylinder 12 are communicated with each other. Also, the pump 66 is stopped and the electromagnetic valve for acceleration slip control 90 is closed.

When the acceleration slip control is completed by stepping on the brake pedal 10, the pilot type on-off valve 92 is closed when the master cylinder pressure becomes substantially equal to the wheel cylinder pressure, so that the entire brake fluid from the front wheel cylinder 18 is closed. Is not discharged, and after the discharge of the brake fluid to the master cylinder reservoir 84 is completed and until the time represented by the count value C elapses, the electromagnetic directional control valve 80 includes the master cylinder 12 and the front wheel. The cylinder 18 remains disconnected. However, since the master cylinder pressure is transmitted through the bypass passage 86, when the electromagnetic directional control valve 80 is switched to the state in which the master cylinder 12 and the front wheel cylinder 18 are communicated with each other, the master cylinder pressure is suddenly transferred to the front wheel cylinder 18. Cylinder pressure is not transmitted and the brake pedal 10 is not suddenly depressed. On the contrary, the brake fluid does not flow into the pressurizing chamber, causing a shock to the brake pedal 10 or generating an impact noise.
The rubber seal of the pressure piston is not damaged. It should be noted that if the brake pedal 10 is pressed so rapidly as to require anti-lock control, the pump 66
Is continuously activated by the antilock control unit.

When the conditions for ending the acceleration slip control other than the depression of the brake pedal 10 are satisfied, S102 to S107 are similarly executed. In this case, since hydraulic pressure is not transmitted from the master cylinder 12, the pilot-type on-off valve 92 functions as a check valve that uses the set load of the spring 118 as the opening pressure, and the wheel cylinder pressure becomes the set load of the spring 118. The electromagnetic directional control valve 80 is switched while the brake fluid is discharged until they become equal to each other, so that the master cylinder 12 and the front wheel cylinder 18 communicate with each other.

At this time, the spring 11 is provided between the pilot type on-off valve 92 and the front wheel cylinder 18.
The brake fluid having a hydraulic pressure corresponding to the set load of 0 remains, and the brake fluid returns to the master cylinder reservoir 84 via the pressurizing chamber of the master cylinder 12 and the check valve. However, the amount of the brake fluid is small and there is no problem.

The count value C representing the amount of brake fluid in the front wheel cylinder 18 is obtained by using values α and β representing the amount of brake fluid supplied to the front wheel cylinder 18 and the amount of brake fluid discharged to the reservoir 54, respectively. After the count condition is satisfied and the acceleration slip control termination condition is satisfied, the count value C is subtracted using the value γ representing the discharge amount of the brake fluid to the master cylinder reservoir 84, and when it becomes 0, the electromagnetic directional control valve 80 The count value C almost represents the amount of brake fluid in the front wheel cylinder 18 when the acceleration slip control end condition is satisfied.
The electromagnetic directional control valve 80 can be switched around when the brake fluid in the pump 66 has just run out, and the pump 66 can be prevented from being uselessly operated.

As is apparent from the above description, in the present embodiment, the brake pedal 10 constitutes a brake operating member, and the acceleration slip control electromagnetic opening / closing valve 90, the pilot type opening / closing valve 92, and S102 of the ROM of the computer. The portion for storing and the portion for executing S102 of the CPU constitute hydraulic pressure reduction means, and the electromagnetic directional control valve 80, S of the ROM.
The part for storing 103 to S107 and the part for executing those steps of the CPU constitute the interruption canceling means.

In the above embodiment, the master cylinder reservoir passage 82 was provided with the electromagnetic slip valve 90 for acceleration slip control and the pilot type on-off valve 92, but as shown in FIG. Valve 9
0 may be omitted.

In this case, the master cylinder reservoir passage 8
The pilot-type on-off valve 160 provided in No. 2 has the same structure as the pilot-type on-off valve 92, but the spring 118
The set load is set to a height at which the wheel cylinder pressure is sufficiently high to suppress wheel rotation even when the pilot pressure is 0 during acceleration slip control, for example, 30 kg / cm ² . The valve opening pressure of the pit pressure on-off valve 160 based only on the set load of the spring 118 is referred to as the minimum valve opening pressure.
Further, a master cylinder pressure sensor 162 for detecting the hydraulic pressure in the pressurizing chamber of the master cylinder 12 and wheel cylinder pressure sensors 164, 166 for detecting the hydraulic pressures of the front wheel cylinders 18 and 32 are provided, and the detection result is an acceleration slip. It is adapted to be supplied to the control unit 140.

During acceleration slip control in this hydraulic brake device, the electromagnetic directional control valve 80 cuts off the communication of the front wheel cylinders 18 and 32 with the master cylinder 12 and switches the communication to the master cylinder reservoir 84. Although the acceleration slip control is performed in the same manner as in the above-described embodiment, since the minimum opening pressure of the pilot-type on-off valve 160 is high, the brake fluid pumped up from the master cylinder reservoir 84 by the pump 66 is at about atmospheric pressure and is at the master pressure. It does not escape to the cylinder reservoir 84, and the hydraulic pressure required for the acceleration slip control is secured.

The acceleration slip control end processing is performed according to the acceleration slip control end processing routine shown in FIG.
This acceleration slip control end processing routine is separately performed for the left front wheel 16 and the right front wheel 32, but the left front wheel 16 will be representatively described.

If any one of the acceleration slip control termination conditions is satisfied, the determination result of S201 is YES, and S
202 is executed, and a brake fluid supply solenoid on-off valve 132
Is closed, the first electromagnetic on-off valve 50 is closed, and the second electromagnetic on-off valve 56 is opened to connect the front wheel cylinder 18 to the reservoir 54.

The brake fluid discharged from the front wheel cylinder 18 to the reservoir 54 is pumped up by the pump 66 and discharged to the master cylinder reservoir 84 via the pilot type on-off valve 160. The discharge pressure of the pump 66 is higher than the minimum opening pressure of the pilot type on-off valve 160, and the brake fluid is discharged to the master cylinder reservoir 84.

Next, S203 is executed, and the master cylinder pressure sensor 162 and the wheel cylinder pressure sensor 16 are
Based on each detection result of 4, it is determined whether the master cylinder pressure is equal to or higher than the wheel cylinder pressure. At the beginning of depression of the brake pedal 10, the master cylinder pressure is low, the determination result in S203 is NO, and the execution of the routine ends.

If the master cylinder pressure is equal to or higher than the wheel cylinder pressure, the determination result of S203 is YES and S20
4 is executed, the electromagnetic directional control valve 80 is switched to a position that allows the front wheel cylinder 18 and the master cylinder 12 to communicate with each other, the first electromagnetic opening / closing valve 50 is opened and the second electromagnetic opening / closing valve 56 is closed, and the front The wheel cylinders 18 and 32 are communicated with the master cylinder 12. Further, the pump 66 is stopped and the execution of the routine ends.

Since the master cylinder pressure is equal to or higher than the wheel cylinder pressure, even if the master cylinder 12 is communicated with the front wheel cylinder 18, the pressurized brake fluid in the front wheel cylinder 18 flows back to the master cylinder 12. After that, the wheel cylinder pressure becomes equal to the master cylinder pressure, and the brake pedal 10
It rises according to the stepping force of.

When the wheel cylinder pressure reaches such a level that the master cylinder 12 and the front wheel cylinder 18 may be communicated with each other, the electromagnetic directional control valve 80 is immediately switched so that the front wheel cylinder 18 becomes the master cylinder. It is not necessary to provide the bypass passage 86 and the check valve 88 that bypass the electromagnetic directional control valve 80 because they are communicated with each other. Even if the wheel cylinder pressure reaches a height at which the electromagnetic directional control valve 80 can be switched,
When the electromagnetic directional control valve 80 cannot be switched until the time required to discharge all the brake fluid in the wheel cylinder when the acceleration slip control end condition is satisfied, the wheel cylinder pressure is sufficiently reduced. However,
There is no possibility that the front wheel cylinder and the master cylinder will not communicate with each other, and the bypass passage 86
This is because it is not necessary to supply the brake fluid from the.

In this embodiment, the pump 66, the pilot type on-off valve 160, and the computer ROM S202.
And a portion of the CPU that executes S202 constitute hydraulic pressure reduction means, and the electromagnetic directional control valve 80, the master cylinder pressure sensor 162, the wheel cylinder pressure sensor 1
64, 166, the portion of the ROM that stores S203 and S204, and the portion of the CPU that executes those steps constitute the disconnection canceling means.

In the embodiment shown in FIGS. 1 to 5, a pilot type on-off valve 92 is provided, and the master cylinder 1
Although the brake fluid supplied from No. 2 was not discharged to the master cylinder reservoir 84, the pilot type on-off valve 92 was omitted and the electromagnetic valve 9 for acceleration slip control was omitted.
Only 0 may be provided. When the brake operating member is operated during the acceleration slip control, the acceleration slip control electromagnetic opening / closing valve 90 is opened to allow the discharge of the brake fluid from the wheel cylinder to the reservoir, and the master cylinder pressure and the wheel cylinder pressure are detected. When they are almost equal, they are closed to complete the hydraulic pressure reduction. However, in this case, it is necessary to provide the pump 66 with a relief valve for returning excess brake fluid to the low pressure side (the master cylinder reservoir 84 or the suction side of the pump 66).

Further, in the embodiment shown in FIGS. 1 to 5, when the acceleration slip control is completed, the first and second electromagnetic on-off valves 5
Although 0 and 56 can be switched to a state in which the wheel cylinder pressure is increased, both the first and second electromagnetic on-off valves 50 and 56 are opened and the brake fluid in the front wheel cylinders 18 and 32 is stored in the reservoir 54. Alternatively, the water may be discharged by pumping up the pump 66. When the discharge capacity of the pump 66 is large, the first electromagnetic opening / closing valve 50 may be closed and the second electromagnetic opening / closing valve 56 may be opened to drain all the brake fluid by pumping up the pump 66.

Further, in the embodiment shown in FIGS. 1 to 5, the electromagnetic directional control valve 80 is sufficient to discharge the excess brake fluid in the front wheel cylinders 18 and 32 after the acceleration slip control termination condition is satisfied. After a lapse of time, the front wheel cylinders 18 and 32 were switched to a position where the master cylinder 12 communicates with each other. However, when the master cylinder pressure becomes higher than the wheel cylinder pressure, the pilot-type on-off valve 92 closes. You may make it switch simultaneously. For example, similar to the embodiment shown in FIGS. 6 and 7, a hydraulic pressure sensor for detecting the master cylinder pressure and a wheel cylinder pressure may be provided and switching may be performed based on the detection results, or a pilot type on-off valve. At 92, it may be detected that the pilot-type on-off valve 92 is closed by the master cylinder pressure based on the detection of the movement of the rod 102, and the electromagnetic direction switching valve 80 may be switched.

Further, in the embodiment shown in FIGS. 1 to 5, the front wheel cylinders 18 and 3 are controlled during the acceleration slip control.
Count value C for counting the amount of brake fluid in 2
Is separately distinguished from the amount of brake fluid supplied to the front wheel cylinders 18 and 32, and the countdown at the end of the acceleration slip control is not performed based on the amount of brake fluid discharged to the master cylinder reservoir 84. It is not essential, but common values may be added or subtracted in S4, S5, and S105.

Further, in the embodiment shown in FIGS. 6 and 7, both the master cylinder pressure and the wheel cylinder pressure are detected, but the wheel cylinder pressure is calculated from the brake fluid amount in the wheel cylinder. It may be estimated. In this case, for example, as in the embodiment shown in FIGS. 1 to 5, the values α and β representing the ratio of the amount of brake fluid supplied to the front wheel cylinders 18 and 32 and the amount of brake fluid discharged are set. A count value C representing the amount of brake fluid in the front wheel cylinders 18 and 32 is obtained by using the value γ representing the amount of brake fluid discharged by the pump 66 from the count value C during the acceleration slip control termination processing.
The wheel cylinder pressure is estimated on the basis of the value C obtained by subtracting and is compared with the master cylinder pressure detected by the master cylinder pressure sensor.

Further, as the shutoff valve for shutting off the communication between the front wheel cylinders 18 and 32 and the master cylinder 12 during the acceleration slip control, it is possible to use an electromagnetic on-off valve instead of the electromagnetic directional control valve 80. In this case, it is necessary to configure the hydraulic circuit so that the brake fluid can be supplied from the acceleration slip control hydraulic pressure source such as the pump 66 to the wheel cylinders of the brakes of the drive wheels with the electromagnetic opening / closing valve closed. Of course there is.

Further, a dedicated accumulator may be provided as a hydraulic pressure source for controlling the acceleration slip and the brake fluid may be supplied to the wheel cylinder of the brake of the drive wheel. The hydraulic pressure is stored in the accumulator by a pump different from the anti-lock control pump and is supplied during the acceleration slip control.

Further, the brake fluid in the wheel cylinder may be directly returned to the reservoir without passing through the anti-lock control solenoid valve. For example, the wheel cylinder and the master cylinder reservoir are directly connected, the brake fluid is discharged from the wheel cylinder at the end of the acceleration slip control, and the discharge is stopped when the wheel cylinder pressure and the master cylinder pressure become almost equal. Of.

Furthermore, in each of the above-mentioned embodiments, the increase, decrease, and retention of the wheel cylinder pressure are performed by the two electromagnetic on-off valves 50, 52, but they may be performed by the three-position electromagnetic directional control valve.

Further, in each of the above-mentioned embodiments, an explanation has been given by taking as an example a device in which the acceleration slip control is performed by using an electromagnetic opening / closing valve for antilock control, but the present invention is not limited to this. Even if the acceleration slip control device provided in the hydraulic brake device or the anti-lock control device is provided, it can be applied to the device that performs the acceleration slip control without using it.

Further, the present invention can be applied to an acceleration slip control device provided in a front and rear two-system hydraulic brake device and an acceleration slip control device for a four-wheel drive vehicle. Besides, the present invention can be implemented in various modified and improved modes based on the knowledge of those skilled in the art without departing from the scope of the claims.

[Brief description of drawings]

FIG. 1 is a system diagram of a hydraulic brake device including an acceleration slip control device according to an embodiment of the present invention.

FIG. 2 is a front sectional view showing a pilot type on-off valve of the acceleration slip control device.

FIG. 3 is a diagram showing a configuration of a RAM of a computer of an acceleration slip control unit of the acceleration slip control device.

FIG. 4 is a flowchart showing a hydraulic pressure counting routine stored in a ROM of the computer.

FIG. 5 is a flowchart showing an acceleration slip control end processing routine stored in a ROM of the computer.

FIG. 6 is a system diagram of a hydraulic brake device including an acceleration slip control device according to another embodiment of the present invention.

7 is a flowchart showing an acceleration slip control end processing routine stored in a ROM of a computer of an acceleration slip control unit of the acceleration slip control device shown in FIG.

[Explanation of symbols]

 10 Brake Pedal 12 Master Cylinder 16 Left Front Wheel 18 Front Wheel Cylinder 30 Right Front Wheel 32 Front Wheel Cylinder 80 Electromagnetic Directional Change Valve 90 Electromagnetic Open / Close Valve for Acceleration Slip Control 92 Pilot Open / Close Valve 140 Acceleration Slip Control Unit 160 Pilot Open / Close Valve

Claims (1)

[Claims] 1. A brake that operates by transmitting a brake fluid pressure generated in a master cylinder to a wheel cylinder in response to an operation of a brake operating member, prevents excessive slippage of driving wheels during acceleration of a vehicle. In order to prevent this, in the acceleration slip control device that shuts off from the master cylinder by the shutoff valve and operates with the hydraulic pressure of the hydraulic pressure source different from the master cylinder, the brake operation member was operated during the acceleration slip control. At this time, the hydraulic pressure lowering means for lowering the hydraulic pressure of the wheel cylinder and the hydraulic pressure lowering means lowers the hydraulic pressure of the wheel cylinder to be substantially equal to the hydraulic pressure of the master cylinder and then shuts off by the shutoff valve. An acceleration slip control device comprising: a disconnection releasing means for releasing.