JP2616191B2 - Reflux type anti-lock brake system - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recirculation type anti-lock brake system having a recirculation pump, and more particularly to a technique for eliminating unnecessary operation of the recirculation pump. .

2. Description of the Related Art A recirculation type anti-lock brake system is generally disclosed in Japanese Patent Application Laid-Open No. 64-67464.
(A) a hydraulic pressure source such as a master cylinder that generates a brake hydraulic pressure in response to operation of a brake operation member such as a brake pedal, (b) a wheel cylinder that operates a brake that suppresses rotation of a wheel, and (c) A reservoir, (d) an electromagnetic valve device for selectively communicating a wheel cylinder with the hydraulic pressure source and the reservoir, and (e) an electromagnetic valve device for maintaining a wheel slip ratio in an appropriate range during vehicle braking. (G) an anti-lock control means for controlling the hydraulic pressure of the wheel cylinder via the solenoid valve, and (f) a pump for pumping brake fluid discharged from the wheel cylinder via the solenoid valve device to the reservoir and collecting the brake fluid in a hydraulic pressure source. Pump control means for starting and stopping the pump.

Problems to be Solved by the Invention In the recirculation type antilock type brake system,
For example, brake fluid remains in the reservoir to reduce the operating noise of the pump and the motor that drives the pump, to prevent wasteful consumption of energy by the pump and the like, and to extend the life of the pump and the like. If not, that is, if it is not necessary to operate the pump, it is required to disable the pump. However, in the conventional recirculation type anti-lock type brake system, the reservoir is independent of whether the brake fluid is actually remaining or not.
It was designed to stop the pump at certain times when it is expected that no brake fluid will remain in the reservoir under any conditions. Therefore, in some cases, the pump continues to operate even though the brake fluid does not remain in the reservoir, causing a problem that the pump, the motor, and the like are operated uselessly.

The present invention has been made to solve this problem.

Means for Solving the Problems And the gist of the present invention is, as shown in FIG. 1, the hydraulic pressure source 1, wheel cylinder 2, reservoir 3, solenoid valve device 4, anti-lock control means 5, pump 6, and Pump control means 7
And a depressurized state detecting means 8 for detecting whether or not the electromagnetic valve device 4 has been switched to a depressurized state in which the wheel cylinder 2 communicates with the reservoir 3, and brake fluid remaining in the reservoir 3. Brake fluid remaining detecting means 9 for detecting whether or not to perform the operation, and changing the pump control means 7 in response to the pressure reduction state detection means 8 detecting that the solenoid valve device 4 has been switched to the pressure reduction state. The pump 6 is started and the pump 6 is stopped in response to the brake fluid remaining detection means 9 detecting that no brake fluid remains.

In the recirculation type anti-lock brake system according to the present invention, the pump control means 7 starts the pump 6 in response to the pressure reduction state detection means 8 detecting that the solenoid valve device 4 has been switched to the pressure reduction state. After that, if the brake fluid remaining detecting means 9 detects that no brake fluid remains in the reservoir 3, the pump control means 7 stops the pump 6.

Effects of the Invention According to the present invention, the pump does not need to be operated when the brake fluid does not actually remain in the reservoir, so that unnecessary operation of the pump or the like is omitted, and the operation noise is reduced and consumption is reduced. Effects such as energy saving and extension of life are obtained.

The present invention is described below with reference to a front engine / rear drive type 4
An embodiment in which the invention is applied to a recirculation type anti-lock type brake system of a wheeled vehicle will be described in detail with reference to the drawings.

In FIG. 2, reference numeral 11 denotes a master cylinder as the hydraulic pressure source 1, which has two independent pressurizing chambers. The master cylinder 11 generates a brake fluid pressure having a height proportional to an operation force of a brake pedal 12 as a brake operation member. The brake fluid pressure generated in one pressurizing chamber is transmitted to the main fluid passage 16 via the proportioning / bypass valve 14. The main fluid passage 16 is bifurcated from the middle, and the front fluid cylinder 2 passes through electromagnetic fluid pressure control valves 18a and 18b, respectively.
0a, 20b. The brake fluid pressure generated in the other pressure chamber is transmitted to the main fluid passage 22 via the proportioning / bypass valve 14. The main liquid passage 22 is also provided with an electromagnetic hydraulic pressure control valve 24, after which the main liquid passage 22 is forked and connected to two rear wheel cylinders 26a, 26b. Two front wheel cylinders 20a,
20b each activates a brake that suppresses the rotation of the left and right front wheels, and has two rear wheel cylinders.
Reference numerals 26a and 26b operate the brakes of the left and right rear wheels, respectively.

The proportioning / bypass valve 14 is a main liquid passage.
If the front system including 16 is normal, the main liquid passage
It has a function of proportionally reducing the brake fluid pressure of the rear system including 22 and transmitting the brake fluid pressure from the master cylinder 11 to the rear wheel cylinders 26a and 26b as it is when the front system fails.

The electromagnetic hydraulic pressure control valves 18a, 18b are always in a pressure-increasing state in which the front wheel cylinders 20a, 20b and the master cylinder 11 are communicated as shown in the figure, but when the solenoid 30 is excited with a relatively large current. Is switched to a reduced pressure state in which the front wheel cylinders 20a and 20b are disconnected from the master cylinder 11 and communicate with the reservoir 32, and the solenoid 30
Is excited by a relatively small current, the front wheel cylinders 20a and 20b are switched to a pressure holding state in which both the master cylinder 11 and the reservoir 32 are shut off. The electromagnetic hydraulic pressure control valve 24 also does not communicate with the pressure increasing state in which the rear wheel cylinders 26a and 26b communicate with the master cylinder 11 and the pressure reducing state in which the electromagnetic pressure control valve 24 communicates with the reservoir 36 in accordance with the switching of the excitation state of the solenoid 34. This switches to the pressure holding state.

Each reservoir 32, 36 is a respective wheel cylinder 20a, 20b, 26a, 2
The brake fluid discharged from 6b is stored under pressure. Specifically, as shown in FIG. 3, a piston 42 is slidably fitted in a cylindrical housing 40, thereby A storage chamber where brake fluid is stored in front of 42
44 is formed, and a spring 46 for constantly urging the piston 42 in a direction to reduce the volume of the liquid storage chamber 44 is provided. An annular rubber seal 48 and an annular rubber magnet 50 for keeping the liquid storage chamber 44 airtight are attached to the outer peripheral surface of the piston 42. Outside the housing 40, the piston 42 is moved to the position closest to the rubber magnet 50 in a state where the piston 42 is at the forward end position (the original position shown in the drawing and the position where the volume of the liquid storage chamber 44 is the minimum). A switch 52 is fixedly provided. The reed switch 52 has a pair of reeds (not shown) that open and close in response to the magnetic force.When the piston 42 is at the forward end position and the rubber magnet 50 is closest to the reed, a pair of reeds is generated by the magnetic force of the rubber magnet 50. The reed is closed, but when the piston 42 is retracted from the forward end position, the reed is opened by its own elastic force. That is, in the present embodiment, the piston 42 and the reed switch 52 function as the remaining brake fluid detecting means 9.

The brake fluid in the reservoir 32 is pumped by a pump 58 shown in FIG. 2, and is returned to the main fluid passage 16 via a pump passage 60. A damper 62 for reducing the discharge pulsation of the pump 58 is connected to the pump passage 60, and a main liquid passage is provided.
A check valve 64 for preventing the brake fluid from flowing back from the 16 side to the damper 62 is provided. Pump for rear system as well
66, a pump passage 68, a damper 70 and a check valve 72. Pumps 58 and 66 also have a common motor 74
Driven by

The front system is also equipped with each front wheel cylinder 20
a, 20b are provided with two recirculation passages 76 that allow the brake fluid to recirculate to the master cylinder 11 by bypassing the electromagnetic fluid pressure control valves 18a, 18b. A check valve 78 is provided to prevent this. The front system is further provided with a bypass passage 84 having a normally-open electromagnetic on-off valve 80 and a check valve 82.When the brake fluid is supplied from the master cylinder 11 to the front wheel cylinders 20a and 20b, Brake fluid is supplied by electromagnetic hydraulic pressure control valves 18a, 18
A sufficient flow rate is supplied through both the valve b and the solenoid on-off valve 80. The rear system also includes a return passage 88 provided with a check valve 86, but does not include a bypass passage.

The reservoirs 32 and 36 are connected to a reservoir 92 that stores brake fluid under atmospheric pressure and supplies the brake fluid to the master cylinder 11 by a return passage 90, and a normally closed electromagnetic on-off valve is provided in the return passage 90. 94 are provided.
The brake pedal 12 is provided with a brake switch 98 for detecting depression of the brake pedal.

The electromagnetic hydraulic pressure control valves 18a, 18b, 24, the solenoid on-off valves 80 and 9
4 and the motor 74 are controlled by an antilock control unit 100 shown in FIG. The unit 100 is mainly composed of a computer, and includes a CPU 102, a ROM 104, a RAM 106, and a bus 108 for connecting them. An input interface 110 is connected to the bus 108, and a rear wheel speed sensor 114 for detecting an average rotational speed of the left and right rear wheels from the rotational speed of the propeller shaft of the vehicle is connected to the input interface 110.
And speed sensors that detect the rotational speed of the left and right front wheels respectively
118 and 120 are connected to the brake switch 98 and the reed switch 52. On bus 108,
The output interface 126 is connected, and the electromagnetic interface control valves 18a, 18b, 24, the electromagnetic switching valves 80, 94, and the motor 74 are connected to the output interface 126. Also, ROM10
4 stores various control programs, including an anti-lock control routine (not shown) and a motor control routine represented by a flowchart in FIG.

In the recirculation type anti-lock brake system configured as described above, the CPU 102 determines whether or not an excessive tendency to lock one of the left and right front wheels and the rear wheels during vehicle braking, that is, the pedaling force of the brake pedal 12 It is determined whether the relationship with the friction coefficient is excessive, and if so, the antilock control routine and the motor control routine are repeatedly executed. The anti-lock control routine is based on the detection result of the rear wheel speed sensor 114, the front left wheel speed sensor 118, or the front right wheel speed sensor 120, and controls the electromagnetic hydraulic pressure control valve 18a so that the slip ratio of each wheel is maintained in an appropriate range. , 18b, and 24 are appropriately switched to one of a reduced pressure state, an increased pressure state, and a maintained pressure state. An example of this antilock control is disclosed in Since it is described in JP-A-64-63448, detailed description is omitted here.

Note that information indicating whether each of the electromagnetic hydraulic pressure control valves 18a, 18b, 24 is currently in a depressurized state is indicated by each of the electromagnetic hydraulic pressure control valves 18a,
18b and 24 are stored in the RAM 106. Further, information indicating whether or not the antilock control is currently being performed is also stored in the RAM 106. One anti-lock control is terminated when, for example, the depression of the brake pedal 12 is released, or the running speed of the vehicle decreases to a minimum value (for example, 3 km / h) at which the anti-lock control is possible. .

The motor control routine is for controlling the motor 74 for driving the pumps 58 and 66, and will be described in detail below with reference to FIG.

In this routine, first, step S1 (hereinafter simply referred to as step S1)
Expressed by S1. The same applies to other steps)
It is determined whether at least one of the two electromagnetic hydraulic pressure control valves 18a, 18b, 24 is in a reduced pressure state. Assuming that this time is the case this time, the result of the determination is YES, and in S2, a command is issued to the electromagnetic on-off valve 94 to close it, and then, in S3, the motor 74 is started, so that the pump 58 , 66 are started. This is the end of the current execution of the present motor control routine.

Thereafter, if any of the three electromagnetic hydraulic pressure control valves 18a, 18b, and 24 shifts to a state where the pressure is not reduced while the execution of the motor control routine is repeated, the determination result of S1 becomes NO, and in S4, It is determined whether the current antilock control has been completed. Assuming otherwise this time, the result of the determination is no, and in S5, the reservoir 32
It is determined whether or not the brake fluid does not remain in the reservoir 32 by determining whether or not the reed switch 52 is closed, that is, whether or not the reservoir 32 is empty. If the reed switch 52 is closed, the piston 42 of the reservoir 32 is at the forward end position (inactive position), so it is determined that no brake fluid remains in the reservoir 32.
If the reed switch 52 is open, the piston 42 is retracted from the forward end position, so it is determined that the brake fluid remains. In this case, if it is assumed that the brake fluid remains, the result of the determination is no, and the current execution of the motor control routine ends.

Thereafter, if the brake fluid does not remain in the reservoir 32 while the execution of the motor control routine is repeated, the determination result in S5 is YES, and in S6, it is determined whether the reed switch 52 for the reservoir 36 is closed. Accordingly, it is determined whether or not the brake fluid remains in the reservoir 36. This determination is based on the above S5. In this case, if it is assumed that the brake fluid remains, the result of the determination is no, and the current execution of the motor control routine ends.

Thereafter, if the brake fluid no longer remains in the reservoir 32, the determination result in S6 is YES, and the motor 74
Are stopped, the pumps 58 and 46 are stopped. In the present brake system, since the motor 74 is shared by the front system and the rear system, the motor 74 is operated until no brake fluid remains in the reservoirs 32, 36 of either system. This is the end of the current execution of the present motor control routine.

Thereafter, if the current antilock control is completed while the execution of the motor control routine is repeated, the determination result in S4 becomes YES, and the motor 74 is stopped in S8. The motor 74 is stopped regardless of whether or not the brake fluid remains in each of the reservoirs 32 and 36. Thereafter, the electromagnetic on-off valve 94 is opened in S9. At present, immediately after the end of the antilock control, the electromagnetic hydraulic pressure control valve 18a is also
Both 8b and 24 are in the pressurized state, that is, each wheel cylinder 20a,
Since the solenoids 20b, 26a, 26b are shut off from the reservoirs 32, 36, the reservoirs 32, 36 communicate with the reservoir 92 via the return passage 90 and the solenoid on-off valve 94 when the solenoid on-off valve 94 is opened. Since each reservoir 32, 36 stores the brake fluid under pressure, if each reservoir 32, 36 communicates with the reservoir 92, the brake fluid remaining in each reservoir 32, 36 will not be assisted by each pump 58, 66. It will be collected in the reservoir 92.

Thereafter, in S10, it is determined whether the reservoir 32 is empty, and in S11, it is determined whether the reservoir 36 is empty. If the brake fluid remains in any of them, one execution of this motor control routine ends without closing the electromagnetic on-off valve 92, but if no brake fluid remains in any of them, , S10 and S11 are both YES, and one execution of the motor control routine ends after the electromagnetic on-off valve 92 is closed in S12.

Therefore, in this embodiment, the reservoir 32 and the
If the brake fluid does not actually remain in any of the 36, the motor 74 is stopped.
8,66 working hours are saved.

Further, in the present embodiment, after the antilock control is completed, the brake fluid remaining in each of the reservoirs 32 and 36 is collected in the reservoir 92 without requiring the operation of the motor 74 or the like. The operating time of 74 etc. is saved.

As is apparent from the above description, in the present embodiment, the part of the antilock control unit 100 that executes the part other than S1 in the motor control routine of FIG. And the electromagnetic hydraulic pressure control valves 18a, 18b, and 24 respectively include a left front wheel system, a right front wheel system,
The solenoid valve device 4 of the rear wheel system is configured, and a rear wheel speed sensor 114,
The front wheel speed sensors 118 and 120, the brake switch 98, and the like constitute the antilock control unit 5 in cooperation with the part related to the antilock control of the antilock control unit 100. Further, in the present embodiment, the part of the antilock control unit 100 that executes S1 in FIG.

Although the embodiment of the present invention has been described in detail with reference to the drawings, the present invention can be implemented in other various modified and improved forms based on the knowledge of those skilled in the art.

[Brief description of the drawings]

FIG. 1 is a block diagram conceptually showing the configuration of the present invention. FIG. 2 is a system diagram showing a recirculation type anti-lock brake system according to one embodiment of the present invention. FIG. 3 is a front sectional view showing the reservoirs 32 and 36 in FIG.
FIG. 4 is a block diagram showing an electric system of the brake system. FIG. 5 is a flowchart showing a portion of the control program stored in the ROM shown in FIG. 4 which is relevant to the present invention. 1: hydraulic pressure source, 2: wheel cylinders 3, 32, 36: reservoir 4: solenoid valve device 5: anti-lock control means 6, 58, 66: pump 7: pump control means 8: brake fluid remaining detection means 11: master Cylinder 18a, 18b, 24: Electromagnetic fluid pressure control valve 20a, 20b: Front wheel cylinder 26a, 26b: Rear wheel cylinder 42: Piston, 52: Reed switch 74: Motor 100: Antilock control unit

Claims (1)

(57) [Claims] A hydraulic pressure source for generating a brake hydraulic pressure in response to an operation of a brake operating member; a wheel cylinder for operating a brake for suppressing rotation of a wheel; a reservoir; An electromagnetic valve device that selectively communicates with the reservoir; and an anti-pressure device that controls the hydraulic pressure of the wheel cylinder via the electromagnetic valve device so that the slip ratio of the wheel is maintained in an appropriate range during vehicle braking. A lock control unit, a pump for pumping up brake fluid discharged from the wheel cylinder to the reservoir via the solenoid valve device and collecting the brake fluid in the hydraulic pressure source, and a pump control unit for starting and stopping the pump. In a reflux type anti-lock type brake system, a pressure-reducing state in which the solenoid valve device communicates the wheel cylinder with the reservoir. Pressure reduction state detection means for detecting whether or not the pressure has been switched to; and brake fluid remaining detection means for detecting whether brake fluid remains in the reservoir, and the pump control means detects the pressure reduction state detection. Means for activating the pump in response to detecting that the solenoid valve device has been switched to a reduced pressure state, and responding to the fact that the brake fluid remaining detecting means has detected that no brake fluid remains in the reservoir. A recirculation type anti-lock type brake system, wherein the pump is stopped.