JPH04121260A - hydraulic brake device - Google Patents

Abstract

PURPOSE:To obtain a bydraulic brake device for a vehicle capable of making effective use of its brake performance in emergency by controlling brake hydraulic pressure at a higher value when operational speed is more than a set value than when the operational speed is equal to or less than the set value CONSTITUTION:In the vicinity of a base end part of a brake pedal 10, an encoder 64 is disposed to detect turning movement speed in working the pedal 10 and is connected to an antiskid controller 50 to send it a pulse signal with every turning movement of the pedal 10 at a very small prescribed angle. When the brake pedal 10 is worked, it is judged whether its operational speed is larger than a reference value or not. When the pulse signals from the encoder 64 are larger in number than a reference value, the pressure intensifying gradient alphaof the brake bydraulic pressure is set to alpha1, but when the signals are smaller in number than the value, alpha is set to alpha2. In this case the set value alpha1 is larger than the set value alpha2.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a hydraulic brake device used for braking a vehicle, and in particular to an electro-hydraulic control means for controlling brake fluid pressure in response to an electrical signal. This invention relates to a hydraulic brake device equipped with a hydraulic brake system.

A conventional hydraulic brake system for a vehicle has means for supplying brake fluid pressure to the brakes in response to the operation of a brake operating member, and furthermore, an electric brake system for controlling the brake fluid pressure in response to an electric signal. Those equipped with hydraulic pressure control means are widely used.

The hydraulic brake device described in Japanese Patent Application No. 2-21053 is one of them. In this hydraulic brake device, the pedal force on the brake pedal, which is a brake operating member, is detected by a pedal force sensor, and the brake fluid pressure corresponding to the pedal force is generated by a hydraulic pressure generator equipped with a reservoir, a pump accumulator, and an electromagnetic hydraulic pressure control valve. caused by
It is designed to be supplied to the brakes.

The anti-skid hydraulic brake system also includes electro-hydraulic control means. For example, the brake fluid pressure generated in the mask cylinder in response to the depression of the brake pedal is controlled by an electromagnetic fluid pressure control device, so that the slip of the wheel against the road surface whose rotation is suppressed by the brake is prevented. This is detected and the brake fluid pressure is controlled to prevent excessive slippage.

As described above, in a vehicle hydraulic brake system equipped with an electro-hydraulic pressure control means, the brake hydraulic pressure is suppressed to a relatively low value at -S for various reasons. For example, in the hydraulic brake device of Japanese Patent Application No. 2-21053,
In order to prevent yawing that does not correspond to the steering state of the steering device from occurring in the vehicle body during braking, the hydraulic pressures of the left and right brakes are appropriately controlled. In addition, in an anti-skid type hydraulic brake system, when braking is performed while the vehicle is running on a so-called straddle road where the left and right friction coefficients are different, anti-skid control is started on the brake with the lower friction coefficient. Despite this, anti-skid control is not performed on the brakes with higher friction coefficients, resulting in a difference in braking force between the left and right sides, causing yawing in the vehicle body. The driver deals with this yawing by steering, but it is difficult to deal with it when yawing occurs suddenly, so if anti-skid control is started on the side where the friction coefficient is low, the Efforts are being made to keep the gradient of pressure increase for the higher brakes low. If the pressure increase gradient is kept low, the occurrence of severe yawing can be avoided, and the driver can sufficiently cope with yawing by steering the vehicle.

Problems to be Solved by the Invention As described above, in a vehicle hydraulic brake system equipped with an electro-hydraulic pressure control means, appropriate braking is performed by controlling the brake fluid pressure, but it is not clear whether the braking is appropriate. Whether or not this happens depends on the situation in which braking is performed. For example, if a situation arises in which the vehicle must be stopped urgently while the vehicle is running, it is better to stop the vehicle in the shortest braking distance possible, even if it means sacrificing ride comfort and driving stability.

However, in conventional hydraulic brake devices equipped with electro-hydraulic control means, such consideration has not been taken, and there has been a problem in that braking performance cannot be effectively demonstrated in an emergency.

In an emergency, the brake fluid pressure is higher than normal (
The object of this invention is to provide a hydraulic brake system for a vehicle that can effectively utilize brake performance in an emergency by controlling the hydraulic brake system.

Means for Solving the Problems The gist of the present invention is as shown in FIG. In a vehicle hydraulic brake device including a brake 2 and an electro-hydraulic pressure control means 3, when the operating speed of the brake operating member 1 is greater than a set value, the brake hydraulic pressure is applied to the electro-hydraulic control means 3, and the operating speed is The reason is that a control command means 4 is provided to control the control higher when the value is less than a set value.

Function: In the vehicle hydraulic brake system according to the present invention, if the operating speed of the brake operating member I is smaller than the set value, it is assumed that normal braking is being performed and a rule established in consideration of ride comfort and running stability is established. Electro-hydraulic control means 3 based on
controls brake fluid pressure. If the operating speed of the brake operating member is higher than the set value, it is assumed that emergency braking is being performed, and the emergency control command means 4 causes the electrohydraulic pressure control means 3 to control the brake fluid pressure to a higher value than normal.

In an emergency, the brakes are applied more forcefully than normal.

Effects of the Invention Therefore, according to the present invention, proper braking is performed during normal braking, similar to a hydraulic brake device equipped with a conventional electro-hydraulic control means, and stronger braking is performed during emergency braking. , it is possible to obtain the effect of being able to effectively deal with emergency situations.

Embodiments Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 2 is a system diagram showing an embodiment in which the present invention is applied to an anti-skid type hydraulic brake device.

The pressing force of the brake pedal 1°, which is a brake operating member, is boosted by the brake booster 12 and transmitted to the mask cylinder 14. The mask cylinder 14 is a tandem cylinder that generates brake fluid pressure in two independent pressure chambers, and the brake fluid pressure generated in one pressure chamber is transmitted to the anti-skid actuator 18 via a fluid passage 16. Furthermore, the fluid is transmitted to the brakes 28.30 of the left and right front wheels 24.26, respectively, via the liquid passages 20.22.

The brake fluid pressure generated in the other pressurizing chamber is transferred to the fluid passage 32. It is transmitted to the brakes 40.42 of the left and right rear wheels 36.38 via the anti-skid actuator 18 and the liquid passage 34. In the middle of the liquid passage 16 and the liquid passage 32,
A blow-up switching/bypass pulp 44 is provided, and when the brake fluid pressure to the brakes 28.30 of the front wheels 2426 is normal, the fluid pressure of the mask cylinder 14 is reduced and the brake fluid pressure to the brakes 28.30 of the rear wheels 2426 is reduced. If the brake fluid pressure to the brake 28.30 of the front wheel 24.26 does not rise normally, the fluid pressure in the mask cylinder 14 is not reduced and the brake 40.4 of the rear wheel 36.38 is transmitted to the brake 40.42.
2.

The anti-skid actuator 18 is controlled by an anti-skid controller 50 mainly composed of a computer, and independently controls the hydraulic pressure of the brake 28 of the left front wheel 24 and the brake 30 of the right front wheel 26, and also independently controls the hydraulic pressure of the brake 28 of the left front wheel 24 and the brake 30 of the right front wheel 26. The hydraulic pressure of the brakes 40 and 42 is commonly controlled. The anti-skid controller 50 includes a speed sensor 52°5 that detects the rotational speed of the front wheels 2426.
4 and speed sensors 56, 5B that detect the rotational speed of the left and right rear wheels 36, 38 are connected, and based on the input signals from these, the slip rate of each wheel is estimated, and if the slip rate is excessive. The anti-skid actuator 18 controls the hydraulic pressure of the brakes on each wheel to prevent this from happening. The computer of the anti-skid controller 50 performs initial settings in response to the ON operation of the ignition switch 60, and starts hydraulic pressure control when the slip rate of each wheel exceeds the set value, so that the vehicle travel speed remains constant at 41 km/h. (
For example, 10 km/h) or less, or brake pedal 1
Hydraulic pressure control is terminated in response to the OFF operation of the brake switch 62 upon release of the brake pedal.

An encoder 64 is disposed near the base end of the brake pedal 10 to detect the rotational speed of the brake pedal 10 when the brake pedal 10 is depressed. The encoder 64 is connected to the anti-skid controller 50, and supplies one pulse signal to the anti-skid controller 50 every time the brake pedal IO rotates by a certain minute angle.

The ROM of the computer that constitutes the main body of the anti-skid controller 50 stores programs shown in the flowcharts of FIGS. 3 and 4. By repeatedly executing these programs at regular intervals, the brake switch Hydraulic pressure control is performed in consideration of the determination of the operating speed of 0 and the determination result.

First, determination of operation speed will be explained.

In step SL (hereinafter simply referred to as SL; the same applies to other steps), the brake switch 62 is turned on.
Based on whether or not the brake pedal 10 is in the depressed state, it is determined whether the brake pedal 10 is in the depressed state. brake pedal 1
In a state where 0 is not depressed, the result of this determination is No, 32 and below are skipped, and one operation speed determination ends without substantially performing anything.

When the brake pedal 10 is depressed, the determination result of Sl becomes YES, and the timer and counter start operating. The timer measures the elapsed time after the brake operation switch 62 is turned on, and the counter counts the pulse signal from the encoder 64 after the brake switch 62 is turned on.

Next, in S3, it is determined whether or not the speed determination flag FS is set, but since the speed determination flag FS is reset in the initial setting of the main routine (not shown), the result of the determination is NO, and S4 It is determined whether the time T1 has elapsed. Initially, the result of this determination is NO, and 35 and below are skipped, but after the time T1 has elapsed, the result of the determination becomes YES, and the operating speed S of the brake pedal 10 is changed in S5.

is the standard value SI! . A determination is made as to whether the value is greater than or not.

The operating speed S8 is expressed by the number of pulse signals emitted from the encoder 64 during the time T2, and if the number of pulse signals is larger than the reference value SHO, the pressure increase gradient α of the brake fluid pressure becomes α1 in S6. If it is smaller, it is set to α2 in S7. Set value α1 is set value α
Greater than 2.

Thereafter, since the speed setting flag FS is set in S8, the determination result in S3 becomes YES, and 34 and below are skipped. The pressure increase gradient α is set after a relatively short time T4 at the beginning of the depression of the brake pedal 10, and is not set thereafter.

Next, hydraulic pressure control will be explained.

At Sll, hydraulic pressure control of the brake 28 of the left front wheel 24 is performed. This hydraulic pressure control is performed for wheels 24°26.36.
The running speed of the vehicle body is calculated based on the rotational speed of the brake 28, and when the rotational speed of the left front wheel 24 becomes smaller than the running speed by more than a certain ratio, the hydraulic pressure of the brake 28 is reduced as shown in FIG. Thereafter, the control is performed to prevent the slip rate of the left front wheel 24 from becoming excessive by increasing, maintaining, or decreasing the hydraulic pressure of the brake 2B while monitoring the rotational speed of the left front wheel 24. Since this is well known, detailed explanation will be omitted.

While the above hydraulic pressure control is not necessary, the left hydraulic pressure control flag FL
is in the reset state, but is set as soon as control is started. Therefore, until the hydraulic pressure control of the left front wheel 24 is started, the determination result in S12 is NO, and S13 and S14 are skipped.

If the hydraulic pressure control of the left front wheel 24 is started, the determination result in S12 becomes YES, and the right hydraulic pressure control flag F is set in S13.
A determination is made as to whether R is set, that is, whether hydraulic pressure control of the right front wheel 26 is being performed. If the result of the determination is YES, steps 315 to S18 are executed, but if the result is NO, suppression control of the pressure increase gradient of the right front wheel 26 is performed in S14.

If the friction coefficients of the road surfaces that the left front wheel 24 and the right front wheel 26 are in contact with are approximately equal, suppression of brake fluid pressure by the anti-skid control should start almost simultaneously on both sides, but the friction on the left side of the road surface If the coefficient is considerably smaller than the friction coefficient on the right side, only the hydraulic pressure on the left front wheel 24 is kept low by anti-skid control, and the hydraulic pressure on the right front wheel 26 is kept low.
The hydraulic pressure is allowed to further increase as the hydraulic pressure of the mask cylinder 14 increases. As a result, a large difference occurs between the left and right braking forces, and a yaw moment is generated that causes the vehicle to turn to the right. This yaw moment is dealt with by the driver operating the steering wheel, but if the yaw moment is too sudden, it cannot be adequately dealt with, and the vehicle body ends up turning to the right. Since it is undesirable for such a situation to occur, in the device of this embodiment, the pressure increase gradient of the front wheel on the side where anti-skid control is not started, in this case the right front wheel 26, is set to
Pressure increase gradient suppression control is performed to make the pressure increase gradient lower than the pressure increase gradient of the mask cylinder 14, and this pressure increase gradient is normally suppressed to a relatively gentle gradient α2 as shown by the broken line in FIG. It will be done. In the pressure increase gradient suppression control of S14, the set value α2 is used as the pressure increase gradient α.

On the other hand, when it is necessary to stop the vehicle urgently, the driver suddenly depresses the brake pedal 10, so that the operation speed S becomes larger than the reference value SRO. In this case, in the pressure increase gradient suppression control of SI4, a relatively large setting value α1 is adopted as the pressure increase gradient α, and the hydraulic pressure of the right front wheel 26 is set at a relatively steep gradient, as shown by the solid line in FIG. The braking force of the right front wheel 26 is increased compared to normal braking, and the braking distance is shortened. Note that if a relatively large pressure increase gradient α1 is adopted, relatively rapid yawing will occur, but
Since the driver is tense when braking, the driver can cope with relatively rapid yawing without any problem.

In steps 315 to 318, the same control as that for the left front wheel 24 is performed on the right front wheel 26, and if the slip of the right front wheel 26 becomes excessive, antiskid control is also performed on the right front wheel 26.

At 319, anti-skid control is performed for the left and right rear wheels 36 and 38. Regarding the left and right rear wheels 36.38, low selection control is applied, that is, the left and right rear wheels 36.38
Anti-skid control is performed focusing on the side with lower rotational speed.

As is clear from the above explanation, in this example,
The portion of the anti-skid controller 50 that executes steps 311 to S19 works together with the anti-skid actuator 18 to constitute the electro-hydraulic control means 3, and the portion of the anti-skid controller 50 that executes steps S1 to S8 constitutes the emergency control command means 4. It consists of

Another embodiment of the invention is shown in FIG.

In the figure, 80 and 82 are front wheel cylinders that operate the brakes on the left and right front wheels, and 84.86
is the rear wheel cylinder that operates the brakes on the left and right rear wheels. These wheel cylinders 80, 82, 84.
At 86, by switching the change valve 88, the hydraulic pressure generated in the mask cylinder 92 based on the depression of the brake pedal 90 and the pressure of the accumulator 96 controlled by the electromagnetic hydraulic pressure control valve 92 based on the depression of the brake pedal 90 are controlled. The higher hydraulic pressure is selectively supplied. 97 is a proportioning half. The pedal force on the brake pedal 90 is detected by a pedal force sensor 98 and supplied to the controller 100. The controller 100 controls the electromagnetic hydraulic pressure control valve 94 based on the depression force on the brake pedal 90 and the vehicle body acceleration supplied from the acceleration sensor 102.
The excitation current is calculated and is caused to be supplied to the electromagnetic hydraulic pressure control valve 94 by the operating amplifier 104. As a result, the hydraulic pressure in the wheel cylinders 80, 82, 84, 86 is adjusted to the brake pedal 90.
The height is controlled to provide a deceleration that corresponds to the pedal force. An encoder 105 for detecting the rotation speed of the brake pedal 90 is also connected to the controller 1oO. The accumulator 96 includes a pump 10 from the reservoir 106.
The brake fluid pumped up by 8 is always stored within a constant hydraulic pressure range. 110 is the pump 10
This is the motor that drives 4. In this hydraulic brake system, hydraulic pressure controlled by the electromagnetic hydraulic pressure control valve 94 is normally supplied to the wheel cylinders 80, 82, 84, 86, but if there is an abnormality on the 'QN hydraulic pressure control valve 94 side. When this occurs, the hydraulic pressure generated in the mask cylinder 92 is supplied to ensure braking force. The control pressure of the electromagnetic hydraulic pressure control valve 94 is set to be slightly higher than the hydraulic pressure of the mask cylinder 92.

The electromagnetic hydraulic pressure control valve 94 is a spool-type electromagnetic hydraulic pressure control valve, and supplies brake hydraulic pressure at a height proportional to the excitation current to the wheel cylinders 80, 82, 84, and 86. The spool is driven in one direction by a force proportional to the hydraulic pressure of the control pressure boat connected to the wheel cylinders 80, 82, 84, 86, while the control force of the force motor is generated with a magnitude proportional to the excitation current. is applied in the opposite direction, and the spool stops at a position where both are balanced, thereby controlling the hydraulic pressure.

ROM of the computer that forms the main body of the controller 100
A program represented by the flowchart in FIG. 7 is stored in .

At 321, the output signal of the pedal force sensor 98 is read, and the pedal force of the brake pedal 90 is detected. S22
, the operating speed of the brake pedal 90 is detected by counting the pulse signals output from the encoder 105. Then, in S23, it is determined whether the operating speed of the brake pedal is greater than the reference value, and if the result of the determination is No, it is determined that normal braking is in progress, and normal brake fluid pressure control is performed in S24. be exposed. In other words, the brake fluid pressure is controlled to a level that provides a deceleration commensurate with the force applied to the brake pedal 9o.

On the other hand, the determination result of S23 is YES, that is,
When the operation speed of the brake pedal 90 is higher than the reference value, control is performed to rapidly increase the brake fluid pressure to a predetermined maximum brake fluid pressure. by this,
During emergency braking, the maximum brake fluid pressure is supplied to the front wheel cylinders 80.82 regardless of the operating speed and depression force of the brake pedal 90, and the maximum fluid pressure is supplied to the rear wheel cylinders 84.86 through the provisioning valve 97. The hydraulic pressure at the height reduced by is reduced to 1, and
Maximum braking force is generated at all brakes, and the braking distance of the vehicle is significantly shortened.

As is clear from the above explanation, in this example,
The part of the controller 100 that executes 321 and S24 works together with the electromagnetic hydraulic control valve 94 to control the electrohydraulic control means 3.
The part of the controller 100 that executes S22, 323, and S25 constitutes the emergency control command means 4.

In the above two embodiments, the rotation speed of the brake pedal 10,900 as a brake operating member is determined by the encoder 64,
105, the brake operation speed can be detected by detecting the brake operation speed. It is also possible to detect speed. Furthermore, it is also possible to detect the hydraulic pressure of the mask cylinder 14 and the like using a hydraulic pressure sensor, and to detect the operating speed of the brake operating member based on the magnitude of the pressure increase gradient.

In addition, in the embodiment described above, the brake fluid pressure was controlled in two stages according to the two stages of the brake operation speed, but the operation speed of the brake operation member is divided into multiple stages, and each It is also possible to perform different brake fluid pressure control for each stage.

In addition, the present invention can be practiced with various modifications and improvements based on the knowledge of those skilled in the art, such as applying the present invention to the hydraulic brake device disclosed in Japanese Patent Application No. 2-21053.

[Brief explanation of drawings]

FIG. 1 is a diagram conceptually showing the configuration of the present invention. FIG. 2 is a system diagram showing an anti-skid type hydraulic brake device which is an embodiment of the present invention. FIGS. 3 and 4 are flowcharts showing a control program for the hydraulic brake device. FIG. 5 is a graph conceptually showing an example of brake fluid pressure control in the hydraulic brake device. FIG. 6 is a system diagram showing a hydraulic brake device according to another embodiment of the present invention. FIG. 7 is a flowchart showing a control program for the hydraulic brake device. IO = Brake pedal 14: Mask cylinder 18: Anti-skid actuator 2B, 30, 40, 42 Brake 50: Anti-skid controller 64: Encoder 80.82: Front wheel cylinder 84.86: Rear wheel cylinder 90 Brake pedal 94: ii Electromagnetic hydraulic pressure control valve 6: Accumulator 100: Controller 105: Encoder Figure 1 Group Figure 3 Figure 42 Cover Figure 7

Claims (1)

[Claims] A vehicle hydraulic brake device comprising an electrohydraulic pressure control means for supplying brake fluid pressure to the brake in response to an operation of the brake operating member and controlling the brake fluid pressure in response to an electric signal, wherein the brake operating member If the operating speed of the brake fluid is greater than a set value, the electro-hydraulic pressure control means is provided with emergency control command means for controlling the brake fluid pressure higher than when the operating speed is below the set value. Pressure brake device.