JP2570805Y2 - Vehicle brake control device - Google Patents

Description

[Detailed description of the invention] "Industrial application field" The invention is an antilock function that prevents the locked state of the wheel during braking, and a traction that prevents the wheel from spinning during starting, turning, accelerating, etc. The present invention relates to a vehicle brake control device having a control function.

Conventional technology Conventionally, as a vehicle brake control device having both an antilock function and a traction control function, for example,
There is one described in JP-A-63-297159.

The brake control device includes a hydraulic pressure supply system that connects a wheel cylinder to a master cylinder, a supply control valve that opens and closes a flow path of the hydraulic pressure supply system, and a hydraulic pressure relief system that connects the wheel cylinder to a reservoir. A discharge control valve for opening and closing the flow path of the hydraulic pressure relief system is provided, respectively, between the reservoir and the hydraulic pressure supply system at a position upstream of the supply control valve, and downstream of the reservoir and the discharge control valve. A hydraulic transport system is disposed so as to connect between the hydraulic relief system at the position and the hydraulic relief system at a position downstream of the reservoir and the discharge control valve. A hydraulic pump is provided in the transport system. Then, the hydraulic pump is alternatively connected to a hydraulic supply system and a hydraulic relief system via one of the two hydraulic transport systems, and the other hydraulic transport system is directly connected to the reservoir. A four-port two-position switching valve is provided so as to extend over both hydraulic transport systems.

At the time of anti-lock control, a hydraulic pump is connected to a hydraulic pressure supply system, and control for releasing brake fluid of a wheel cylinder to a reservoir through a hydraulic pressure relief system in accordance with wheel speed information; and a hydraulic pump. Control to return the brake fluid from the reservoir to the hydraulic pressure supply system and repressurize the wheel cylinders.At the time of traction control, the hydraulic pump is connected to the hydraulic pressure relief system by the switching valve to brake the master cylinder. The liquid can be made to act on the wheel cylinder from the hydraulic pressure relief system.

[Problem to be Solved by the Invention] However, in such a brake control device, since the switching valve is a spool type valve having four ports and two positions, the clearance between the spool and the housing and the surface of the sliding surface thereof are provided. High dimensional accuracy and processing accuracy are required for roughness, etc., and it tends to be expensive, and if these accuracy are insufficient, fluid leakage will occur, and part of the brake fluid from the master cylinder will flow to the reservoir during braking. As a result, problems such as an increase in the amount of depression of the brake pedal occur.

The present invention has been proposed in view of the above circumstances, and aims to provide a brake control device that aims to reduce costs, reduce the occurrence of liquid leakage and the like, and effectively exhibit both functions of antilock and traction control. I do.

[Means for Solving the Problems] The brake control device according to the present invention includes a first hydraulic pressure supply system connecting between the master cylinder and the wheel cylinder, and a hydraulic pressure relief system connecting between the wheel cylinder and the reservoir. And a control valve provided in each of these systems for opening and closing respective paths, and connecting between the reservoir and the first hydraulic pressure supply system at a position upstream of the control valve in the first hydraulic pressure supply system, and A hydraulic pressure return system having a pressure feeding means, and a first hydraulic pressure supply system provided at a position upstream of a junction of the hydraulic pressure return system and the first hydraulic pressure supply system. A control switching valve that opens and closes, a second hydraulic pressure supply system that connects between the first hydraulic pressure supply system located upstream of the control switching valve and the reservoir, and a second hydraulic pressure supply system, A traction control valve for opening and closing the path of the second hydraulic pressure supply system, The control valve and the control switching valve in the first hydraulic pressure supply system are configured as normally open valves that are opened when traction control is not performed, and the traction control valve is operated by a master cylinder when a brake pedal is depressed. When the brake fluid pressure is generated, the passage of the second fluid pressure supply system is closed, and when the brake pedal is not depressed and the brake fluid pressure is not generated by the master cylinder, the passage of the second fluid pressure supply system is opened. When the brake pedal is not depressed, the excess brake fluid stored in the reservoir by the antilock control and the traction control is removed from the master cylinder after the completion of the control. It is characterized by comprising means for returning to.

[Operation] In the vehicle brake device of the present invention, (1) during normal braking, the brake fluid of the master cylinder is released from the hydraulic pressure supply system to the wheel by opening the flow path of the hydraulic pressure supply system by the control switching valve. Can be supplied to the cylinder. Also, during this normal braking,
Since the traction control valve is set so that the flow path of the second hydraulic pressure supply system is closed by the brake hydraulic pressure supplied from the master cylinder, the brake fluid does not flow directly from the master cylinder to the reservoir.

(2) During antilock control, the control valve of the hydraulic pressure supply system is closed and the control valve of the hydraulic pressure relief system is opened to release the brake fluid of the wheel cylinder to the reservoir. A pressure holding mode that holds the brake pressure of the wheel cylinder constant by closing both the valve and the control valve of the hydraulic pressure relief system,
Select the pressure increase mode, in which the control valve of the hydraulic pressure release system is closed and the control valve of the hydraulic pressure supply system is opened, and the brake fluid in the reservoir is supplied to the wheel cylinder by the hydraulic pressure return system. can do. In the antilock control, the traction control valve is set so that the flow path of the second hydraulic pressure supply system is closed by the brake hydraulic pressure supplied from the master cylinder. Does not flow.

(3) At the time of traction control, in a state where the control switching valve is closed and the flow path of the hydraulic pressure supply system between the master cylinder and the wheel cylinder is shut off, the control valve of the hydraulic pressure relief system is closed and the hydraulic pressure supply system is closed. By opening the control valve, the pressure increase mode in which the brake fluid of the master cylinder is supplied to the wheel cylinder by the hydraulic pressure return system pumping means, the control valve of the hydraulic pressure supply system, and the control valve of the hydraulic pressure relief system are both closed. A pressure holding mode that maintains the brake pressure of the wheel cylinder at a constant pressure, and a pressure reduction that drains the brake fluid of the wheel cylinder to the reservoir by closing the control valve of the hydraulic pressure supply system and opening the control valve of the hydraulic pressure relief system Mode can be selected. In addition, at the time of this traction control, the traction control valve is set so as to open the flow path of the second hydraulic pressure supply system. Can be effectively supplied to the wheel cylinder.

That is, in the vehicle brake device of the present invention, in addition to the conventional control valve, a control switching valve and a traction valve having only a function of simply opening and closing the flow path are provided, and the antilock control and the traction control are performed by these two valves. This makes it possible to simplify the entire configuration, reduce costs, reduce the occurrence of liquid leakage and the like, and perform reliable control.

On the other hand, the control valve and the control switching valve in the first hydraulic pressure supply system are configured as normally open valves that are opened when traction control is not being performed, and further, the traction control valve is operated by depressing a brake pedal. A means for opening the flow path of the second hydraulic pressure supply system and returning the excess brake fluid stored in the reservoir by the antilock control and the traction control to the master cylinder after the end of the control. (I) After the end of the anti-lock control and the traction control, and at a normal time when the brake pedal is not depressed, the excess brake fluid stored in the reservoir is released through the traction control valve in the open state. Can be returned to the master cylinder, which keeps the amount of brake fluid in the reservoir to a minimum, At the time of control, more brake fluid than necessary does not flow back to the master cylinder, thereby preventing adverse effects on the master cylinder. (II) After the anti-lock control and traction control are completed, and depressing the brake pedal During normal times, the excess brake fluid stored in the reservoir is sent to the master cylinder through the hydraulic pressure return system and the first hydraulic pressure supply system by the hydraulic pressure return system pressure feeding means through the control switching valve in the open state. The brake fluid in the reservoir is kept to a minimum, and during antilock control, the brake fluid does not flow back to the master cylinder more than necessary, adversely affecting the master cylinder. Is prevented. That is, in the present invention, the above (I)
The two systems shown in (II) and (II) allow the excess brake fluid stored in the reservoir to be returned to the master cylinder, so that if any trouble occurs in one system, the other system will function. By doing so, the trouble can be avoided and the reliability of the device can be improved. (III) Since the control valve and the control switching valve are in the open state at the start of the normal brake operation, The brake fluid pressure generated in the master cylinder due to the depression of the brake pedal can be immediately supplied to the wheel cylinders through the control switching valve and the control valve, thereby improving the brake operation feeling.

"Embodiment" Hereinafter, an embodiment of the brake control device of the present invention will be described with reference to the drawings.

FIG. 1 shows a first embodiment of the present invention. In this brake control device, reference numerals provided in a hydraulic pressure supply system 3 between a master cylinder 1 and a wheel cylinder 2 are provided. 4
Is a supply control valve for controlling the supply of brake fluid to the wheel cylinder 2, and a valve indicated by reference numeral 7 provided in the hydraulic pressure relief system 6 between the master cylinder 1 and the reservoir 5 is a discharge control valve. A valve indicated by reference numeral 8 connecting a downstream position of the discharge control valve 7 and an upstream position of the supply control valve 4 is a hydraulic pressure return system. Is provided with a pumping means 9 such as a pump. At the position upstream of the junction of the hydraulic pressure supply system 3 and the hydraulic pressure return system 8, control is performed to open and close the flow path of the hydraulic pressure supply system 3 to switch between antilock control and traction control as described later. A switching valve 10 is provided, and a second hydraulic pressure supply system 11 that connects the master cylinder 1 to a position upstream of the pressure feeding means 9 of the hydraulic pressure return system 8 is provided at a position further upstream than the control switching valve 10. The second hydraulic pressure supply system 11 is provided with a traction control valve 12 for opening and closing the flow path. The hydraulic pressure return system 8 and the hydraulic pressure supply system 3 at a position upstream of the control switching valve 10.
An overflow system 13 is provided between the hydraulic pressure supply system 3 and a relief valve 14 that allows only the flow from the hydraulic pressure return system 8 to the hydraulic pressure supply system 3.

The control switching valve 10 is in an `` open '' state when the power is off,
A normally open solenoid valve that is in the "closed" state at N is used. As for the supply control valve 4 and the discharge control valve 7, the former is a normally open type solenoid valve and the latter is a normally closed type solenoid valve as in the conventional example.

The traction control valve 12 is provided with a through hole 16 in the housing 15 so as to form a part of the second hydraulic pressure supply system 11 and a piston 18 housed in a cylinder chamber 17.
The piston 18 has a front end facing the through hole 16, and the interior of the cylinder chamber 17 is connected by the piston 18 to the atmosphere chamber 20 communicating with the atmosphere through the hole 19 and the second hydraulic pressure supply system 11 via a valve operation system 21. The working pressure chamber 22 is partitioned. Normally, when the piston 18 is separated from the through hole 16 by the return spring 23 to open the second hydraulic pressure supply system 11 and the brake hydraulic pressure from the master cylinder 1 acts on the working pressure chamber 22,
By pressing the piston 18 to close the through hole 16,
The second hydraulic pressure supply system 11 is shut off.

Reference numeral 24 denotes a brake pedal, reference numeral 25 denotes a brake switch, reference numeral 26 denotes a reservoir attached to the master cylinder 1, and reference numeral 27 denotes a hydraulic pressure supply system to other wheel cylinders.

Next, a control method by the brake control device configured as described above will be described separately for normal brake control, antilock control, and traction control.

[Normal brake control] In a normal state where the brake pedal 24 is not depressed, as shown in FIG. 1, the flow path of the hydraulic pressure supply system 3 between the master cylinder 1 and the wheel cylinder 2 is opened, and
The traction control valve 12 of the second hydraulic pressure supply system 11 is open, and the master cylinder 1 and the hydraulic pressure return system 8 are in communication.

When the brake pedal 24 is depressed, the brake fluid is supplied from the master cylinder 1 to the wheel cylinder 2 via the hydraulic pressure supply system 3 to generate a braking force.
At this time, since the brake fluid pressure also acts on the working pressure chamber 22 of the traction control valve 12 of the second fluid pressure supply system 11 via the valve operation system 21, the flow path of the second fluid pressure supply system 11 is shut off. The brake fluid does not flow through the fluid pressure return system 8.

[Anti-Lock Control] When the tendency of locking the wheels is detected during braking, control is performed by appropriately selecting from the following three modes according to the wheel speed information.

In this table, UP is a pressure increasing mode for increasing the brake fluid pressure of the wheel cylinder 2, HOLD is a pressure maintaining mode for keeping the brake fluid pressure of the wheel cylinder 2 constant, and DOWN is a pressure reducing mode for decreasing the brake fluid pressure of the wheel cylinder 2. In addition to indicating the mode, ON and OFF indicate the connection state of the power supply. During this antilock control, the control switching valve 10 is maintained in the OFF state.

That is, when the wheels tend to lock, for example, the pressure reducing mode is selected, and the supply control valve 4 controls the hydraulic pressure supply system 3.
And the discharge control valve 7 of the hydraulic pressure relief system 6 is opened to discharge the brake fluid of the wheel cylinder 2 to the reservoir 5. When the lock tendency is small or the lock release tendency is caused by the pressure reduction mode, the pressure holding mode is selected to shut off both the flow paths of the hydraulic pressure supply system 3 and the hydraulic pressure relief system 6. The brake fluid pressure of the wheel cylinder 2 is kept constant. At this time, the pressure feeding means 9 of the hydraulic pressure return system 8 is also operated, and when the locking tendency is eliminated, the mode is switched to the pressure increasing mode, and the supply control valve 4 opens the hydraulic pressure supply system 3 so that the wheel cylinder is opened. 2. Feed the brake fluid again into 2.

When the brake pedal 24 is depressed as described above, the traction control valve 12 controls the second hydraulic pressure supply system 11.
Is shut off, the brake fluid does not flow directly from the master cylinder 1 to the reservoir 5, and the operation of the pumping means 9 does not affect the master cylinder 1. Also, at normal times, the control valve 12 is open, and the amount of fluid in the reservoir 5 is kept to a minimum, so that more brake fluid than necessary does not flow back to the master cylinder 1 during antilock control. Has no adverse effect on

[Traction control] The control mode when the tendency of the wheels to spin at the time of starting or the like is detected is as shown in the following table.

During this traction control, the brake pedal 24 is not depressed, so that the traction control valve 12 connects the master cylinder 1 and the hydraulic pressure return system 8 with the second hydraulic pressure supply system 11 opened.

In the pressure increasing mode, the control switching valve 10 closes the flow path of the hydraulic pressure supply system 3 to cut off the connection between the master cylinder 1 and the wheel cylinder 2, and the pressure feeding means 9 operates to brake the master cylinder 1. The liquid is sequentially sent to the wheel cylinder 2 via the second hydraulic pressure supply system 11, the hydraulic pressure return system 8, and the hydraulic pressure supply system 3, and a braking force is applied. When the acceleration or the slip rate of the wheel is small or the acceleration or the slip rate is reduced to a predetermined value by the pressure increasing mode, the pressure holding mode is selected and the supply control valve 4 of the hydraulic pressure supply system 3 is closed. Thus, the pressure of the wheel cylinder 2 is kept constant. When the slip ratio of the wheel is maintained within the predetermined target value for a predetermined period of time, and it is detected that the idling tendency has been eliminated, the discharge control valve 7 of the hydraulic pressure relief system 6 is opened in the decompression mode, and the wheel is released. The brake fluid in the cylinder 2 is discharged to the reservoir 5. The brake fluid stored in the reservoir 5 is returned to the master cylinder 1 by the pressure feeding means 9 via the overflow system 13. If the brake fluid remains excessively in the reservoir 5 after the traction control is completed, the brake fluid is returned to the master cylinder 1 via the second hydraulic pressure supply system 11 and the brake fluid of the hydraulic pressure return system 8 is supplied to the control switching valve 10. To the master cylinder 1 through

The pumping means 9 starts and stops when the traction control is started, and stops when the brake pedal 24 is depressed even during the traction control.

In the brake control device of the first embodiment, the traction control valve 12 is opened and closed by the brake fluid pressure of the master cylinder 1, so that it is not necessary to provide a separate drive source and the operation is reliable. Further, the control switching valve 10 is not a spool type valve as in the conventional example, but uses an electromagnetic valve which has been used in a brake control device, and has high reliability.

"Second embodiment" Fig. 2 shows a second embodiment of the present invention.
The brake control device of the embodiment has a traction control valve.
The cylinder chamber 17 of 31 is divided into a working pressure chamber 22 and a return pressure chamber 32, and the working pressure chamber 22 is provided with a valve operating system from the master cylinder 1.
The valve operating system 33 is connected to the return pressure chamber 32 from the hydraulic pressure supply system 3. The second hydraulic pressure supply system 11 is connected to the traction control valve from the reservoir 26 of the master cylinder 1.
Connected to 31. The hydraulic pressure return system 8 is provided with an accumulator 34 at a position downstream of the pressure feeding means 9, and is connected to the hydraulic pressure return system 8 via a pressure release valve 35. The pressure release valve 35 is a normally closed type solenoid valve.

In the brake control device thus configured, when the internal pressure of the accumulator 34 is equal to or lower than a predetermined pressure, the pressure is accumulated according to the flowchart of FIG. That is, the internal pressure P _{ACC of the} accumulator 34 is smaller than the predetermined pressure P _O (S1), and the vehicle stops (S1).
2) When the brake switch 25 is not operating (S3)
At the same time, the control switching valve 10 and the supply control valve 4 are shut off and the pressure release valve 35 is opened (S4), and the pumping means 9 is operated (S5), whereby the brake fluid in the reservoir 26 of the master cylinder 1 is discharged. It is stored in the accumulator 34.
Then, when any one of S1 to S3 is negative, the pumping means 9 is stopped (S6).

During the anti-lock control, the control switching valve 10 and the pressure release valve 35 are both turned off, and the opening and closing of the supply control valve 4 and the discharge control valve 7 are controlled in the same manner as in the first embodiment. Is done.

On the other hand, the mode at the time of traction control is set as follows.

That is, in the brake control device of this embodiment, the pressure release valve 35 is opened in the pressure increasing mode, and the pressure of the wheel cylinder 2 is increased by using the brake fluid accumulated in the accumulator 34. In this case, since the brake fluid can be supplied by utilizing the pressure of the accumulator 34, the pressure feeding means 9 does not need to be used, and may be used only at the time of accumulating the pressure. Therefore, since there is no possibility that excessive brake fluid pressure acts on the fluid pressure return system 8, the overflow system as in the first embodiment shown in FIG.
13 and the relief valve 14 may be unnecessary.

In the second embodiment, the brake fluid is sucked from the reservoir 26 of the master cylinder 1 when the accumulator 34 accumulates the pressure, so that the suction pressure does not act on the master cylinder 1 or the fluid pressure supply system 3. An adverse effect on the seal portion and the like of the master cylinder 1 can be prevented.
In the traction control, it has been described that the pumping means 9 is not operated. However, when the accumulator 34 is used only for the purpose of improving the responsiveness when the traction control is started, the pumping is performed similarly to the first embodiment. Means 9 may be activated.

[Third Embodiment] FIG. 4 shows a third embodiment. This brake control device comprises a traction control valve 41 of a second hydraulic pressure supply system which is normally opened and a normally closed solenoid valve. It was done. In this case, since the antilock control is the same as in the above-described embodiments, only the mode at the time of traction control is shown in the following table.

In this case, the normally closed solenoid valve is normally open and the traction control valve of the second hydraulic pressure supply system 11 is opened.
The control for handling as 41 is performed. However, even after the traction control is completed, the normally closed solenoid valve is kept ON for a certain period of time, and the brake fluid stored in the reservoir 5 becomes the second fluid. It returns to the master cylinder 1 via the pressure supply system 11.

[Effects of the Invention] As is apparent from the above description, (1) In the vehicle brake device of the present invention, in addition to the conventional control valve, the control switching valve and the traction having only the function of simply opening and closing the flow path. Valves are provided, and these two valves are used to switch between antilock control and traction control. This makes it possible to simplify the overall configuration and reduce costs, and to reduce the occurrence of liquid leakage and the like. It is possible to perform reliable control.

(2) (I) After the anti-lock control and the traction control are completed, and in a normal state where the brake pedal is not depressed, the excess brake fluid stored in the reservoir is transferred to the master cylinder through the open traction control valve. The brake fluid in the reservoir is kept to a minimum, and during antilock control, the brake fluid does not flow back to the master cylinder more than necessary, adversely affecting the master cylinder. Can be prevented.

(II) After the anti-lock control and the traction control are completed and the brake pedal is not depressed in a normal state, the excess pressure stored in the reservoir by the pressure-feeding means of the hydraulic pressure return system through the open control switching valve. The brake fluid can be returned to the master cylinder through the fluid pressure return system and the first fluid pressure supply system, whereby the amount of the brake fluid in the reservoir is kept to a minimum, and the anti-lock control is performed more than necessary. It is possible to prevent the brake fluid from flowing back to the master cylinder, thereby preventing the brake fluid from adversely affecting the master cylinder. That is, in the present invention, the above (I)
The two systems shown in (II) and (II) allow the excess brake fluid stored in the reservoir to be returned to the master cylinder, so that if any trouble occurs in one system, the other system will function. By doing so, the trouble can be avoided, and the reliability of the device can be improved.

(III) Since the control valve and the control switching valve are open at the start of the normal brake operation, the brake fluid pressure generated in the master cylinder due to the depression of the brake pedal is immediately transmitted through the control switching valve and the control valve. The brake operation can be supplied to the wheel cylinder, thereby improving the brake operation feeling.

[Brief description of the drawings]

FIG. 1 is a piping diagram showing a first embodiment of the brake control device of the present invention, FIG. 2 is a piping diagram showing a second embodiment of the present invention, and FIG. FIG. 4 is a flow chart showing a control procedure, and FIG. 4 is a piping diagram showing a third embodiment of the present invention. 1 ... master cylinder, 2 ... wheel cylinder, 3 ...
... hydraulic pressure supply system (first hydraulic pressure supply system) 4 ... supply control valve 5
... Reservoir, 6 ... Hydraulic relief system, 7 ... Discharge control valve, 8 ... Hydraulic pressure return system, 10 ... Control switching valve, 11 ... Second
Hydraulic pressure supply system, 12… Traction control valve, 13… Overflow system, 14… Relief valve, 15… Housing, 16
…… Through hole, 17 …… Cylinder chamber, 18 …… Piston, 19…
... holes, 20 ... atmosphere chamber, 21 ... valve operating system, 22 ... operating pressure chamber, 23 ... return spring, 24 ... brake pedal, 25 ... brake switch, 26 ... reservoir, 27 ...
Hydraulic pressure supply system, 31… Traction control valve, 32… Return pressure chamber, 33… Valve operation system, 34… Accumulator, 35
... pressure release valve, 41 ... traction control valve.

Claims (1)

(57) [Scope of request for utility model registration] 1. A first hydraulic pressure supply system connecting between a master cylinder and a wheel cylinder, a hydraulic pressure relief system connecting between a wheel cylinder and a reservoir, and a path provided in each of these systems. A control valve for opening and closing the valve, and a first valve located upstream of the control valve in the reservoir and the first hydraulic pressure supply system.
A hydraulic pressure return system connected to the hydraulic pressure supply system and having a pressure feeding means on the way, and a first hydraulic pressure supply system located upstream of a junction of the hydraulic pressure return system and the first hydraulic pressure supply system Provided in
A control switching valve that opens and closes a path of the first hydraulic pressure supply system; a second hydraulic pressure supply system that connects between the first hydraulic pressure supply system upstream of the control switching valve and the reservoir; A traction control valve provided in the two-hydraulic-pressure supply system to open and close a path of the second-hydraulic-pressure supply system;
While comprising a normally open valve that is opened when traction control is not performed, the traction control valve,
When the brake hydraulic pressure is generated by the master cylinder when the brake pedal is depressed, the path of the second hydraulic pressure supply system is closed. When the brake pedal is not depressed and the brake hydraulic pressure is not generated by the master cylinder, the second hydraulic pressure supply is performed. When the brake pedal pressure is not depressed, the excess brake fluid stored in the reservoir by the anti-lock control and the traction control is released by opening the system path and responding based on the brake fluid pressure from the master cylinder. A brake control device for a vehicle, comprising: means for returning to the master cylinder after control is completed.