JPH06263023A - Reflux type antilock brake device - Google Patents

Abstract

PURPOSE:To avoid an increase in braking distance caused by a decrease in brake operating force by kick back cased when a reflux type antilock brake device is operated. CONSTITUTION:An electromagnetic type brake operating force assisting device 10 is installed in a position opposed to a brake pedal 12. This device is composed of a member 48 to be attracted composed of a magnetic substance installed on the brake pedal 12 and an attracting member 46 containing a coil 42 and a yoke 44 installed on a car body 40. Simultaneously when antilock control is started, an electric current is carried to the coil 42, and the member 48 to be attracted is attracted to the attracting member 46, and brake operating force of a driver is assisted by this attraction force, and an increase in a braking distance by kick back caused by antilock control is avoided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for avoiding a decrease in brake operating force due to kickback in a reflux type antilock brake device.

[0002]

2. Description of the Related Art An anti-lock brake system includes a brake operating device, a master cylinder for converting an operating force of the brake operating device into a hydraulic pressure, a brake cylinder for operating a brake for suppressing wheel rotation, and an anti-lock control device. It is configured to include and. Then, the reflux type anti-lock control device is provided between the reservoir, the brake cylinder, the master cylinder, and the reservoir,
At least a switching valve device that can switch between a pressure-reduced state that allows pressure reduction of the brake cylinder and a pressure-increased state that allows pressure increase, a pump that pumps up brake fluid in the reservoir and returns it to the master cylinder, and wheel rotation. It is configured to include a wheel rotation speed sensor that detects a speed, and an antilock control unit that controls the switching valve device based on the detection result of the wheel rotation speed sensor to maintain the wheel slip in an appropriate range. .

In the return type anti-lock brake device equipped with the return type anti-lock control device, a so-called kickback phenomenon occurs during its operation. Hydraulic pressure is generated in the master cylinder according to the operating force applied to the brake operating device by the driver. This hydraulic pressure is
The braking force is supplied to the brake cylinder via the switching valve device, and the braking device is driven to generate a braking force. At this time, if the operating force of the brake operating device (hereinafter referred to as the brake operating force) is excessive in relation to the friction coefficient of the road surface and the braking force becomes too large and the slip ratio of the wheels increases, the antilock control device Is activated to adjust the slip ratio of the wheel. The adjustment of the slip ratio is performed by switching the passage for transmitting the hydraulic pressure of the brake fluid by the switching valve.

When the hydraulic pressure in the brake cylinder is excessive and the slip ratio is large, the communication state is changed from the state in which the brake cylinder and the master cylinder are in communication to the state in which the brake cylinder and the reservoir are in communication. By switching and a part of the brake fluid in the brake cylinder flows out to the reservoir, the fluid pressure in the brake cylinder is reduced and the slip ratio of the wheels is reduced. However, at this time, it is difficult to stop the hydraulic pressure drop of the brake fluid in an optimal braking force state and maintain it, so that the hydraulic pressure in the brake cylinder is usually reduced more than necessary, and the braking force is also reduced. It decreases with it. The master cylinder and the brake cylinder are made to communicate again in order to recover the reduced braking force and obtain the optimum braking force. However, when the hydraulic pressure in the master cylinder is high, the slip ratio becomes too high again, so the communication is switched by the switching valve. After that, the braking force is adjusted by repeatedly switching the switching valve.

Here, if the brake fluid in the brake cylinder is repeatedly discharged to the reservoir, the brake fluid in the master cylinder may decrease, and it may not be possible to generate sufficient hydraulic pressure. Liquid is pumped back to the master cylinder. The pump is started at the start of the antilock control and continuously operated until the antilock control is completed. Therefore, the amount of brake fluid in the master cylinder is temporarily reduced when the master cylinder and the brake cylinder are made to communicate with each other, and then is recirculated by the pump to be recovered. At this time, the pulsation of the pump and the change in the brake fluid volume in the master cylinder due to the switching of the switching valve give a displacement to the brake operating device and make the driver feel a thrust-back force that opposes the brake operating force. This is kickback.

When the thrust-back force is applied by kickback, the braking force of the driver may be weakened and the braking force may be reduced. When the driver does not continue to apply a constant brake operating force, the position of the brake operating device is gradually retracted by being pushed by the kickback thrusting force, and the brake operating force is reduced and the braking force is reduced. In order to avoid this reduction in braking force, it is necessary to prevent the reduction in operating force due to kickback.

As one of the means, there is an attempt to eliminate kickback itself.
Japanese Patent Laid-Open No. 112162 discloses a brake device that generates hydraulic pressure in a phase that cancels fluctuations in the hydraulic pressure of the brake fluid. This is to detect a variation in the hydraulic pressure of the brake fluid with a sensor and generate a hydraulic pressure in a phase that cancels the variation based on the detection signal.

[0008]

However, in the case of using the brake device described in the above publication, after the pressure fluctuation of the brake hydraulic pressure is detected by the sensor, the hydraulic pressure of the opposite phase to the detected phase is generated, so that the response There is a delay and kickback is not fully avoided. Therefore, the brake device does not sufficiently prevent the reduction of the braking operation force, and thus the avoidance of the reduction of the braking force is insufficient. Therefore, it is an object of the present invention to develop a technique for surely preventing a decrease in brake operating force due to kickback and satisfactorily avoiding a decrease in braking force.

[0009]

In order to solve the above-mentioned problems, the present invention provides a brake operation force assisting device for assisting an operation force of a brake operating device in an antilock brake device operating state in a reflux type antilock brake device. The point is to provide.

[0010]

In the present invention, the brake operation force assisting device is used in order to avoid a decrease in brake operation force due to kickback that occurs when the antilock brake device is activated. The brake operation force assisting device is a means for further adding assist operation force to the brake operation force applied by the driver,
For example, a means using an electromagnet can be used. When an electromagnet is used, at the same time when the antilock control is started, a magnetic field is generated between a pair of magnetic bodies fixed to the brake operating device and the vehicle body, and a force that drives the brake operating device in the same direction as the brake operating force. Is added. By assisting the operation force in this way, the brake operation force is increased, and even when kickback is applied and the brake operation force of the driver is reduced, sufficient braking force is secured.

The auxiliary operating force may be applied intermittently or continuously during the antilock control.
If the driver greatly reduces the brake operating force while the assist is stopped when the auxiliary operating force is applied intermittently, the brake operating device returns to the original position and the anti-lock control is released to brake the vehicle. The operation of the brake operation force assisting device of the operating device is stopped. On the other hand, when the auxiliary operating force is continuously applied, the operation of the brake operating force assisting device is not stopped due to the reduction of the brake operating force of the driver. Therefore, for example, when the driver's foot is separated from the brake pedal, which is the operating member of the brake operating device,
The auxiliary operating force is released by configuring so that the operation of the brake operating force assisting device is stopped when the detection means such as the pressure sensor and the limit switch detects it.

[0012]

As described above, when the anti-lock control device is activated, the brake operating force is increased by the auxiliary operating force applied by the brake operating force assisting device as an assist to the driver's brake operating force. Therefore, even if the brake operation force of the driver decreases due to kickback, the brake operation force as a whole becomes large enough to maintain the antilock control, and the decrease of the braking force is avoided.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, the brake operation force assisting device 10
Is provided at a position facing the brake pedal 12. The brake pedal 12 is connected to the master cylinder 16 via a transmission member 14. Master cylinder 16
Is connected to a liquid passage branched into two, one is connected to the electromagnetic direction switching valve 18, and the other is connected to the pump 22 via the check valve 20. The pump 22 is driven by the motor 24. One port of the electromagnetic directional control valve 18 is connected to the brake cylinder 28 provided in the wheel portion 26, and the other one port is connected to the reservoir 30. The electromagnetic directional control valve 18 is normally in a state where the master cylinder 16 and the brake cylinder 28 are in communication with each other, and the brake cylinder 28 is connected to the master cylinder 1 when antilock control is performed.
6 is switched to a pressure increasing state in which it communicates with the reservoir 30, a pressure reducing state in which it communicates with the reservoir 30, and a holding state in which neither the master cylinder 16 nor the reservoir 30 communicates. Further, the wheel portion 26 is provided with a wheel rotation speed sensor 32,
It is connected to the controller 34. The controller 34 is connected to the electromagnetic directional control valve 18, the motor 24, and the brake operation force assisting device 10 and controls them. As shown in FIGS. 2 and 3, the brake operating force assisting device 10 is fixed to the vehicle body 40 and includes the coil 42 and the yoke 4.
A suction member 46 including 4 and a suction member 48 made of a magnetic material and attached to the brake pedal 12 are provided. An exciting current is supplied from the controller 34 to the coil 42, and a magnetic attractive force is generated between the attracting member 46 and the attracted member 48. This suction force assists the driver's brake operation force F.

Next, the operation will be described. Hydraulic pressure is generated in the master cylinder 16 in accordance with the brake operating force F applied to the brake pedal 12 by the driver. This hydraulic pressure passes through the electromagnetic directional control valve 18 and the brake cylinder 2
8, the braking device is driven and a braking force is generated. At this time, the brake operation force F is excessively large in relation to the friction coefficient of the road surface, and when the braking force becomes too large and the slip ratio of the wheels increases, the wheel rotation speed sensor 32
The controller 34 operates based on the information of (1) to adjust the slip ratio of the wheel. The slip ratio is adjusted by switching the hydraulic pressure passage by the electromagnetic directional control valve 18.
At this time, the master cylinder 16 associated with the switching of the hydraulic passages
Since the change in the amount of internal brake fluid and the pulsation of the discharge pressure of the pump 22 are transmitted to the brake pedal 12, the driver feels so-called kickback.

The brake operation force assisting device 10 prevents the driver's brake operation force F from being lowered by such kickback. When the antilock control is started, an exciting current is supplied from the controller 34 to the coil 42, the attracted member 48 is attracted by the attracting member 46, and the brake operating force F is assisted. Therefore, as shown in FIG. 4, the brake operating force F after the antilock control is started is equal to the brake operating force assisting device 10
It is shifted upward by the auxiliary amount compared to the case where the switch is not activated.

The solid line in FIG. 4 shows the change over time of the brake operating force F when the brake operating force is not assisted. The anti-lock control is started at the time t1 when the brake operating force F becomes F1, reaches the maximum at t2, and is then pushed back by the kickback to be reduced. When the driver feels kickback, the braking force F is reduced in the case of a driver who is not accustomed to kickback, or in the case of an elderly person or a woman with weak leg strength, and the antilock control is started at time t3. Brake operating force F1 corresponding to hydraulic pressure
It may fall below and fall to F3.

When the brake operation force F3 is slightly lower than F1, the hydraulic pressure of the master cylinder 16 as a hydraulic pressure source for increasing the pressure of the brake cylinder 28 becomes insufficient even if the controller 34 continues the antilock control. , The pressure increase gradient for the antilock control becomes small, and the antilock control cannot be performed well. Also, the brake operating force F3
Is smaller than F1, even if the electromagnetic direction switching valve 18 is switched to the pressure increasing state by the controller 34, the hydraulic pressure in the brake cylinder 28 does not increase and the braking force becomes insufficient.
In either case, the braking distance increases. On the other hand, the alternate long and short dash line in the figure shows the relationship between the brake operating force F and the time when the brake operating force auxiliary device 10 is activated at the same time when the antilock control is started after the brake operation is started. By operating the brake operation force assisting device 10, the brake operation force F increases from F1 to F2. Therefore, even if the driver presses the kickback to reduce the brake operating force F, the brake operating force F is maintained at a value larger than F1 at the start of the antilock control, and the master cylinder 16 has the hydraulic pressure of the brake cylinder 28. Sufficient pressure can be maintained as a source. Therefore, anti-lock control is performed well, and good braking performance can be maintained.

Further, the brake operating force assisting device 10 does not always operate, but in this embodiment, as shown in FIG. 5, a time for checking the driver's intention to release the brake operating force is set at regular time intervals. Is provided, and the braking operation force F is not assisted during that period. Therefore,
If the driver does not significantly reduce the brake operating force F and continues to depress the brake pedal 12, the brake operating force F
However, if the driver significantly reduces the brake operating force F, the brake pedal 12 sucks the brake operating force assisting device 10 while the brake operating force F is not being assisted. The brake pedal 12 is released from the force application space, or the depression of the brake pedal 12 is significantly eased.

As is clear from the above, in this embodiment,
The brake pedal 12 and the transmission member 14 constitute a brake operating device, the electromagnetic directional switching valve 18 constitutes a switching valve device, and the controller 34 constitutes antilock control means.

Although one embodiment of the present invention has been described in detail above, the present invention is not limited to this embodiment, and for example, a brake operating force assisting device may be provided in the brake operating force transmitting member. Well, not limited to electromagnetic type,
A mechanical auxiliary operating force may be applied to the brake operating device. Besides, the present invention can be implemented in various modified and improved modes based on the knowledge of those skilled in the art without departing from the scope of the claims.

[Brief description of drawings]

FIG. 1 is a system diagram of a reflux type antilock brake device that is an embodiment of the present invention.

FIG. 2 is a front view showing a part of the brake operation force assisting device of the above embodiment in section.

3 is a cross-sectional view taken along the line AA of FIG.

FIG. 4 is a graph showing a relationship between a brake operating force and time in the above embodiment.

FIG. 5 is a graph showing the operation timings of the controller and the brake operating force assisting device in the above embodiment.

[Explanation of symbols]

 10 Brake Operation Force Auxiliary Device 12 Brake Pedal 16 Master Cylinder 18 Electromagnetic Directional Change Valve 22 Pump 24 Motor 28 Brake Cylinder 30 Reservoir 32 Wheel Rotation Speed Sensor 34 Controller 42 Coil 44 Yoke 46 Suction Member 48 Suctioned Member

Claims (1)

[Claims] 1. A brake operating device, a master cylinder that converts an operating force of the brake operating device into a hydraulic pressure, a brake cylinder that operates a brake that suppresses wheel rotation, a reservoir, the brake cylinder, and the master cylinder. Is provided between the reservoir and the reservoir, and at least
A switching valve device that can switch between a pressure-reducing state that allows pressure reduction of the brake cylinder and a pressure-increasing state that allows pressure increase, a pump that pumps up the brake fluid in the reservoir and returns it to the master cylinder, and the rotational speed of the wheels. Anti-rotation brake that includes a wheel rotation speed sensor that detects the wheel speed and anti-lock control means that controls the switching valve device based on the detection result of the wheel rotation speed sensor to maintain the slip of the wheel in an appropriate range. The recirculation type anti-lock brake device, wherein the device has a brake operation force assisting device for assisting the operation force of the brake operating device while the antilock control means is in operation.