JPH04123963A - Reflux antilock type brake system - Google Patents

Abstract

PURPOSE:To reduce an operating noise as well as to curtail the extent of spending energy by controlling a pump so as to be stopped at a time when a brake fluid residue detecting means has detected a fact that a brake fluid is not left behind in a reservoir after the pump is started by a pump control means. CONSTITUTION:This brake system is provided with a hydraulic source 1 such as a master cylinder or the like, a wheel cylinder 2, a reservoir 3, a solenoid valve gear 4 interconnecting this wheel cylinder 2 alternatively to the hydraulic source and the reservoir 3, and an antilock control means 5 controlling hydraulic pressure in the wheel cylinder via this solenoid valve gear 4. Also it is provided with a pump 6, drawing up a brake fluid exhausted to the reservoir 3 by way of the solenoid valve gear 4 and recovering it, and a pump control means 7. In this case, there is provided a brake fluid residue detecting means 8 which detects whether the brake fluid is left behind in the reservoir 3 or not. When this detecting means 8 has detected a fact that there is no brake fluid by the pump control means 7, the pump 6 is controlled so as to be stopped.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a recirculation type anti-lock brake system equipped with a recirculation pump, and particularly relates to a technique for omitting unnecessary operation of the recirculation pump. .

Conventional technology: As disclosed in Japanese Patent Application Laid-open No. 64-67464, the conventional recirculation anti-lock brake system generally includes:
(a) A hydraulic pressure source such as a mask cylinder that generates brake hydraulic pressure in response to the operation of a brake operating member such as a brake pedal; (b) A wheel cylinder that operates a brake that suppresses rotation of the wheels; (C) (d) an electromagnetic valve device that selectively communicates the wheel cylinder with the hydraulic pressure source and the server; (f) a pump that pumps up brake fluid discharged from the wheel cylinder to the reservoir via the electromagnetic valve device and recovers it to a hydraulic pressure source; g) pump control means for starting and stopping the pump.

Problems to be Solved by the Invention In the recirculation type anti-lock brake system, for example, it is necessary to reduce the operating noise of the pump and the motor that drives it, to prevent wasteful energy consumption by the pump, etc. In order to extend the life of these pumps, it is required that the pumps do not operate when no brake fluid remains in the reservoir, that is, when there is no need to operate the pumps. However, with conventional recirculation anti-lock type pre-registration systems, brake fluid remains in the reservoir regardless of whether brake fluid actually remains in the reservoir. It was designed to shut down the pump at a certain time when it was expected to run out.

Therefore, in some cases, the pump may continue to operate even though there is no liquid remaining in the reservoir, resulting in a problem that the pump, motor, etc. are operated unnecessarily.

The present invention has been made with the aim of solving this problem.

As a means to solve the problem, the gist of the present invention is as shown in FIG. Reservoir 3 Solenoid valve device 4
．． Anti-lock control means5. In the recirculation type anti-lock J5II brake system including a pump 6 and a pump control means 7, a brake fluid residual detection means 8 is provided to detect whether or not brake fluid remains in the suspension bar 3, and a pump control means 8 is provided. The means 7 is configured to stop the pump 6 when the brake fluid residual detecting means 8 detects that no brake fluid remains.

In the recirculation type anti-lock braking system according to the present invention, after the pump 6 is started by the pump control means 7, if the brake fluid remaining detection means 8 detects that no brake fluid remains in the server 3, , the pump 6 is stopped by the pump control means 7.

Effects of the Invention Therefore, according to the present invention, the pump does not need to be operated when no brake fluid actually remains in the reservoir, so unnecessary operation of the pump etc. is omitted, reducing operating noise and consumption. Effects such as energy savings and extended life can be obtained.

EXAMPLE Hereinafter, an example in which the present invention is applied to a recirculation type anti-lock braking system for a front-end/rear-drive four-wheel vehicle will be described in detail with reference to the drawings.

In FIG. 2, 11 is a mask cylinder serving as a liquid pressure source I, and is provided with two independent pressurizing chambers. This mask cylinder 11 generates a brake fluid pressure having a height proportional to the operating force of a brake pedal 12 as a brake gear operating member. The brake fluid pressure generated in one pressurizing chamber passes through the provisioning/bypass valve 17I to the main fluid passage I.
6. The main fluid passage 16 is generally divided in the middle and is connected to front wheel cylinders 20a and 20b via electromagnetic hydraulic pressure control valves 8a and 18b, respectively. The brake fluid pressure generated in the other pressurizing 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, and after passing through this, the main liquid passage 22 is divided into two legs and connected to two rear wheel cylinders 26a and 26b. Two front wheel cylinders 20a, 2
0b actuates the brakes that suppress the rotation of the left and right front wheels, respectively, and the two rear cylinders 26a and 26b actuate the brakes of the right rear wheel, respectively.

When the front system including the main fluid passage 16 is normal, the provisioning/bypass valve 14 proportionally reduces the brake main fluid pressure in the rear system including the main fluid passage 22, In the event of failure, the brake fluid pressure from the mask cylinder 11 is maintained as is, and the Yapoir cylinder 26a,
26b.

The electromagnetic hydraulic pressure control valves 18a and 18b are always in an increased pressure state that communicates the front wheel cylinders 20a and 20b with the mask cylinder II, as shown in the figure, or when the solenoid 30 is energized with a relatively large current. When the front wheel cylinders 20a, 20b are cut off from the mask cylinder 11 and communicated with the reservoir 32, the front wheel cylinders 20a, 20b are switched to a reduced pressure state.
0b is switched to a pressure holding state in which it is cut off from both the mask cylinder 11 and the reservoir 32. The electromagnetic hydraulic pressure control valve 24 also operates according to the switching of the excitation state of the solenoid 34.
The rear wheel cylinders 26a and 26b are switched between an increased pressure state in which they are communicated with the mask cylinder 11, a reduced pressure state in which they are communicated with the reservoir 36, and a pressure maintained state in which they are not communicated with any of them.

Each reservoir 32,36 is connected to each wheel cylinder 20a, .
20b, 26a, 261) is stored under pressure. Specifically, as shown in FIG. 3, a piston 42 is slidably fitted into a cylindrical housing 40. 11 of 42, thereby
A liquid storage chamber 44 in which the brake main liquid is stored is formed on the 1f side, and a spring 46 is provided to constantly bias the piston 42 in a direction to reduce the volume of the liquid storage chamber 44. It is. An annular rubber seal 48 and an annular rubber magnet 50 are attached to the outer peripheral surface of the piston 42 to keep the liquid storage chamber 44 airtight.

On the outside of the housing 4o, there is a position closest to the rubber magnet 50 when the screw 1 hem 42 is at the forward end position (the original position shown in the figure, where the volume of the liquid storage chamber 44 is the minimum). A reed switch 52 is fixedly disposed at. The reed switch 52 is equipped with a pair of reeds (not shown) that open and close in response to magnetic force, and when the screws I to 42 are at the forward end position and are closest to the rubber magnet 50 or the reeds, the magnetism of the rubber magnet 50 is removed. Either the pair of leads closes due to the force, or the lead opens due to its own elastic force when the screw I/N 42 is retracted from the forward end position. Zunawaji,
In this embodiment, the piston 42 and the reed switch 52 function as the brake main fluid residual detection means 8.

The brake fluid in the reservoir 32 is pumped up by a pump 58 shown in FIG.
It will be returned to 6. A damper 62 for reducing the discharge pulsation of the pump 58 is connected to the pump passage 6o, and a check valve 64 is provided for preventing the reverse flow of the liquid into the damper 62 from the main liquid passage 16 side. . Similarly, the rear system also includes a pump 66 and a pump passage 68. damper 70
and a check valve 72. Pumps 58 and 66 are also driven by a common motor 74.

The front system also includes each freon 1 to wheel cylinder 2.
Two reflux passages 76 are provided that allow the main liquid to flow back from the electromagnetic hydraulic pressure control valves 1.8a and 20b to the mask cylinder 11 by bypassing the electromagnetic hydraulic control valves 1.8a and 8b, and each reflux passage 76 has a Check valve 78 that prevents backflow of brake main fluid
Or is provided.

The front system is further provided with a bypass passage 84 equipped with a normally open electromagnetic on-off valve 80 and a check valve 82.
From mask cylinder 11 to Freon 1 to wheel cylinder 2
When the brake main liquid is supplied to 0a and 20b, the brake main liquid is supplied to the electromagnetic hydraulic pressure control valve 18a.

18b and the electromagnetic on-off valve 80 at a sufficient flow rate. The rear system also includes a recirculation passage 88 with a check valve 86 or no bypass passage.

The reservoirs 32 and 36 of 111f are connected by the reflux passage 90,
It is connected to a reservoir 92 that stores the main brake liquid under atmospheric pressure and supplies the main brake liquid to the mask cylinder 11, and the recirculation passage 90 is provided with a normally closed electromagnetic on-off valve 94. Further, the brake pedal 12 includes:
A brake switch 98 is provided to detect depression of the brake switch.

The electromagnetic hydraulic pressure control valves 18a, 18b, 24. The electromagnetic on-off valves 80 and 94 and the motor 74 are controlled by an anti-lock control unit 1-100 shown in FIG. This unit 100 is mainly composed of a computer, and is based on Taite, C.
PU1.02. ROM104. It includes a RAMI 06 and buses 1 and 08 that connect them. bus 108
An input interface l1.0 is connected to the input interface 110, and a rear wheel speed sensor 114 that detects the average rotational speed of the left and right rear wheels from the rotational speed of the propeller shirt 1 of the vehicle, and a rear wheel speed sensor 114 that detects the rotational speed of the left and right front wheels, respectively. Speed sensors 118 and 120 that detect the brake switch 98 and the reed switch 52 are connected. Bus 1.08 also has an output interface 12
6 is connected to this output interface 126, and the electromagnetic hydraulic control valves 18a, 1llib, 24 and the electromagnetic (il)
The l-closing valves 80, 94 and the motor 74 are connected. Further, the ROM 104 stores various control programs including an anti-lock control routine (not shown) and a motor control routine represented by flowcharts 1 to 1 in FIG.

In the recirculation type anti-lock brake system configured as described above, when braking the vehicle, the CPU I02 determines whether an excessive locking tendency has occurred in either the left or right front wheels or the rear wheels, that is, the depression force on the brake pedal I2. It is determined whether or not is excessive in relation to the coefficient of friction of the road surface, and if so, the anti-lock control routine and the motor control routine are each repeatedly executed. The anti-lock control routine uses the rear wheel speed sensor 114. Based on the detection results of the front left wheel speed sensor 118 or the front right wheel speed sensor 120, the electromagnetic hydraulic pressure control valves 18a, 181) and 24 are set to a reduced pressure state or an increased pressure state so that the slip ratio of each wheel is maintained within an appropriate range. Anti-lock control is carried out to appropriately switch to either the pressure holding state or the pressure holding state. An example of this anti-lock control is described in Japanese Patent Application Laid-open No. 1987-6463448, of which the present applicant is the applicant. A detailed explanation will be omitted here.

Note that information indicating whether or not each electromagnetic hydraulic pressure control valve 18a, 181), 24 is currently in a depressurized state is provided in RA, M2O3 in relation to each electromagnetic hydraulic pressure control valve 18a, 18b, 24.
is stored in the memory.

Further, information indicating whether or not anti-lock control is currently being performed is also stored in the RAM 106. Also,
- times of anti-lock control, for example, the brake pedal 12
The process is terminated when the driver releases the pedal or the vehicle speed drops to the lowest value (for example, 3 km/h) at which anti-lock control is possible.

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

In this routine, first, in step Sl (hereinafter simply referred to as Sl; the same applies to other steps),
three electromagnetic hydraulic pressure control valves], 8a, 18b, 24 (
It is determined whether one of the two is in a reduced pressure state. Assuming that is the case this time, the result of the judgment will be yes,
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, thereby starting the pumps 58, 66. This completes the current execution of this motor control routine.

Thereafter, if none of the three electromagnetic hydraulic pressure control valves 18a, 18b, and 24 are in a reduced pressure state while the execution of this motor control routine is repeated, the determination result of Sl becomes NO, and in S4, It is determined whether the current anti-lock control has ended or not. Assuming that is not the case this time, the result of the determination is NO, and in S5, it is determined whether or not the reed switch 52 for the reservoir 32 is closed, thereby determining whether or not brake fluid remains in the reservoir 32. In other words, it is determined whether the reservoir 32 is empty or not. If the reed switch 52 is closed, the first screw 42 of the reservoir 32 is at the forward end position (non-operating position), so it is determined that there is no brake fluid remaining in the reservoir 32. On the other hand, if the reed switch 52 is open, Since brake parts 1 to 42 have retreated from their forward end positions, it is determined that brake fluid remains. If it is assumed that the brake fluid remains this time, the result of the determination will be NO, and the current execution of this motor control routine will end.

Thereafter, if no brake fluid remains in the reservoir 32 while the execution of this motor control routine is repeated, S5
The determination result is YES, and in S6, the reservoir 3
By determining whether or not the reed switch 52 for 6 is closed, it is determined whether or not brake fluid remains in the reservoir 36. This determination is based on S5 above.

If it is assumed that the brake fluid remains this time, the result of the determination will be no, and the current execution of this motor control routine ends.

After that, if there is no brake fluid remaining in the reservoir 32, the determination result in S6 becomes YES, and the motor 74 is stopped in S7, and the pump 58 is stopped.
．． 46 or stopped. In this brake system, since the motor 74 is shared by the front system and the rear system, the motor 74 can be operated until no brake fluid remains in the brake servers 32, 36 of either system. This completes the current execution of this motor control routine.

Thereafter, as this motor control routine is repeatedly executed, the determination result in S4 becomes YES as to whether or not the current anti-lock control has been completed, and the motor 74 is stopped in S8. The motor 74 is stopped regardless of whether brake fluid remains in each reservoir 32, 36. Thereafter, the electromagnetic on-off valve 94 is opened in S9.

Currently, the anti-lock control has just ended, and the electromagnetic hydraulic pressure control valves 1.8a, 181) and 24 are in an increased pressure state, that is, each wheel cylinder 20a, 20b, 26a.

261] from each reservoir 32, 36], so when the electromagnetic on-off valve 94 is opened, each reservoir 3
2.36 communicates with the reservoir 92 via a reflux passage 90 and an electromagnetic on-off valve 94. Since each reservoir 32.36 stores brake fluid under pressure, if each reservoir 32.36 is in communication with the server 92, the brake fluid remaining in each reservoir 32.36 will not be assisted by each pump 58.66. It will be collected into the reservoir 92.

Thereafter, in S10 it is determined whether the reservoir 32 is empty, and in Sll it is determined whether the reservoir 36 is empty. If 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 brake fluid does not remain in any of them, , S10 and Sll are both YES, and after the electromagnetic on-off valve 92 is closed in SI2, one execution of this motor control routine ends.

Therefore, in this embodiment, the operating time of motor 74 and pumps 58, 66 is saved because motor 74 is stopped when no brake fluid actually remains in either reservoir 32 or 36.

Furthermore, in this embodiment, after the anti-lock control ends, the brake fluid remaining in each reservoir 32, 36 is collected into the reservoir 92 without requiring the motor 74 or the like to operate. 74 etc. operation time is saved.

As is clear from the above explanation, in this example,
The portion of the anti-lock control unit 100 that executes the motor control routine shown in FIG.
b, 24 constitute the solenoid valve device 4 for the left front wheel system, right front wheel system, and rear wheel system, respectively, and the rear wheel speed sensor 114. Front wheel speed sensor 1. ], S8 I 20. The brake switch 98 and the like constitute the anti-lock control means 5 in cooperation with the anti-lock control section of the anti-lock control unit 1-100.

Hereinafter, one embodiment of the present invention has been described in detail with reference to the drawings, but the present invention can be implemented in various other forms with various modifications and improvements based on the knowledge of those skilled in the art.

[Brief explanation of the drawing]

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 which is an embodiment of the present invention. Figure 3 is the second
FIG. 7 is a front sectional view showing the reservoir 3236 in the figure. FIG. 4 is a block diagram showing the electrical system of the Bregie system. FIG. 5 is a flowchart I. showing a portion of the control program stored in the ROM in FIG. 4 that is closely related to the present invention. 1: Hydraulic pressure source 2: Wheel cylinder 3.32
．． 36: Reservoir 4: Solenoid valve device 5: Anti-lock control means 6.58, 66: Pump 7: Pump control means 8: Breigi fluid residual detection means 11: Mask cylinders 18a, 18b, 24: Electromagnetic hydraulic pressure control valve 20a, 20b
: Front pole cylinder 26a, 26b: Rear wheel cylinder 42, piston 52 Reed switch 74 Motor 100/Anti-lock control unit Applicant: Yota Motors Co., Ltd.

Claims (1)

[Scope of Claims] A hydraulic pressure source that generates brake hydraulic pressure in response to the operation of a brake operating member; a wheel cylinder that operates a brake that suppresses rotation of a wheel; a reservoir; and an electromagnetic valve device that selectively communicates with the reservoir and the hydraulic pressure of the wheel cylinder is controlled via the electromagnetic valve device so that the slip rate of the wheel is maintained within an appropriate range when the vehicle is braked. anti-lock control means; a pump that pumps up brake fluid discharged from the wheel cylinder to the reservoir via the electromagnetic valve device and recovers it to the hydraulic pressure source; and a pump control means that starts and stops the pump. In the recirculation type anti-lock brake system, the brake fluid residual detection means detects whether brake fluid remains in the reservoir, and the brake fluid residual detection means detects whether brake fluid remains in the reservoir. A recirculation type anti-lock brake system, characterized in that the pump is stopped in response to detecting that there is no remaining fuel.