JPH06211122A - Auxiliary brake device of vehicle - Google Patents

Abstract

PURPOSE:To prevent a brake locking of an auxiliary brake device even in the running condition on a low mu road, by reducing the braking force of the auxiliary brake means when the difference between the signal values of the first and the second detecting means to detect a driving wheel and a nondriving wheel is larger than a specific value. CONSTITUTION:A controller 14 calculates the front wheel side mean wheel speed and the rear wheel side mean wheel speed depending on the signals form wheel speed sensors 12, and at the same time, finds the wheel speed difference DELTAV by reducing the rear wheel side mean wheel speed from the front wheel side mean wheel speed. After that, when the wheel speed difference DELTAV is larger than a specific value A, the controller 14 starts the control so as to reduce the braking force of an auxiliary brake means. In this case, it is considered that the rear wheel side mean wheel speed is smaller remarkably compared with the front wheel side mean wheel speed, and the rear wheels R are liable to be brake-locked. As a result, it can be decided that the braking force of the rear wheels R by the auxiliary brake means is too large, and the braking force is to be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an auxiliary braking device for vehicles.

[0002]

2. Description of the Related Art An auxiliary brake device mounted on a large vehicle such as a truck is composed of, for example, an exhaust brake part, an electromagnetic retarder part, a power retard part, etc., and reduces the driving force transmitted to driving wheels to reduce the braking force. Is generated. That is, when the driver turns on the auxiliary brake switch, the exhaust brake part and the power tard part generate resistance to reciprocating motion of the engine piston, and
The electromagnetic retarder unit generates a resistance force of the rotational movement of the driving force transmission shaft, absorbs a part of the driving force transmitted to the driving wheels, and brakes the driving wheels.

The braking force by the auxiliary braking device is set weaker than the braking force by the service braking device, but by using it together with the service braking device, the size and durability of the service braking device can be reduced. be able to.

[0004]

However, the above-mentioned conventional auxiliary braking device operates when the driver operates a switch, and a similar braking force is exerted regardless of the magnitude of the frictional resistance between the road surface and the wheels. generate. The frictional resistance between the road surface and the wheels changes depending on various conditions such as the road surface and the vehicle speed.
Therefore, for example, if the auxiliary brake device is operated while a so-called empty truck is traveling on a road having a small friction coefficient in relation to the wheels, that is, a low μ road, a weak brake of only the auxiliary brake device is generated. Even with the force, this braking force may become larger than the friction resistance, and in such a case, there is a problem that the driving wheels are brake-locked and traveling stability deteriorates.

The present invention has been made to solve the above problems, and an object of the present invention is to provide an auxiliary brake device for a vehicle capable of preventing the brake lock of the drive wheels.

[0006]

In order to achieve the above object, according to the present invention, auxiliary braking means for reducing the driving force of the driving wheels, and first and second means for detecting the rotational states of the driving wheels and the non-driving wheels are provided. When the difference between the signal value supplied from the second detection means and the first detection means and the signal value supplied from the second detection means is larger than a predetermined value, the braking force of the driving wheels by the auxiliary braking means is excessive. And the controller for reducing the braking force of the auxiliary braking means.

[0007]

The controller monitors the rotational states of the driving wheels and the non-driving wheels via the first and second detecting means. The auxiliary braking means affects the driving wheels but not the non-driving wheels, and the controller can detect the brake lock of the driving wheels based on the signal value from each detecting means. That is, when the difference between the signal value supplied from the first detection means and the signal value supplied from the second detection means is larger than a predetermined value, the controller determines that the braking force of the driving wheels by the auxiliary braking means is excessive. It is determined that there is, and the braking force of the auxiliary braking means is reduced. Therefore, the brake lock of the drive wheels is avoided.

[0008]

An embodiment of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 shows an embodiment of an auxiliary brake device to which the present invention is applied. An auxiliary brake device 10 for reducing a driving force transmitted from an engine 1 to a rear wheel R, which is a drive wheel, is an auxiliary brake device, a wheel. The auxiliary brake means is composed of a speed sensor 12, a controller 14, etc., and an auxiliary brake means is provided with an exhaust brake section 16, an electromagnetic retarder section 17, and a power retard section 18.

The exhaust brake section 16 is a braking means for providing an opening / closing valve in the exhaust pipe of the engine 1 to reduce the passage area in the exhaust pipe to increase the engine exhaust pressure and obtain a braking force. The electromagnetic retarder unit 17 includes, for example, a rotor that rotates integrally with a propeller shaft and a coil that is fixed to the vehicle body and applies a magnetic field to the rotor. The electromagnetic retarder unit 17 converts the rotational energy of the rotor into heat energy and releases it. It is a braking means that obtains power. The power tard part 18 cuts fuel of the engine 1 and adjusts valve timing and the like to generate a positive pressure in the combustion chamber when the piston rises and a negative pressure in the cylinder when the piston descends to obtain a braking force. It is a means.

The controller 14 is composed of a microcomputer and has a storage device such as a ROM / RAM, an input / output device and the like. On the input side of this controller 14,
The wheel speed sensor 12, the auxiliary brake switch 20, the brake pedal switch 22 and the like are electrically connected. The wheel speed sensor 12 is provided for each wheel. The wheel speed sensor 12 is composed of a grooved rotor that rotates integrally with the wheel and a pickup coil that is fixed to the vehicle body and faces the grooved rotor. The rotational speed of the grooved rotor is magnetically measured by the pickup coil. It senses and detects the rotational speed of the wheels. The auxiliary brake switch 20 is arranged on the operation panel of the driver's seat and is turned on when the auxiliary brake device 10 is operated. The auxiliary brake switch 20 that has been turned on supplies an on signal to the controller 20. Further, the brake pedal switch 22 is arranged in a brake pedal mechanism (not shown) of the service brake device, and supplies an ON signal to the controller 20 when the brake pedal is depressed.

It is desirable that the wheel speed sensor 12 also serves as the wheel speed sensor 12 of the ABS device in a vehicle equipped with an ABS (antilock brake system). An exhaust brake unit 16, an electromagnetic retarder unit 17, and a power retard unit 18 are electrically connected to the output side of the controller 14. Therefore, the controller 14 can individually operate and release the exhaust brake unit 16, the electromagnetic retarder unit 17, and the power retard unit 18, and reduce the braking force as an auxiliary braking unit. Also, the controller 1
A pilot lamp 21 is also electrically connected to the output side of 4. The pilot lamp 21 is arranged on the operation panel of the driver's seat and is operated by the controller 14 to light up.

An auxiliary brake control program is stored in the storage device of the controller 14. The controller 14 executes this control program when the auxiliary brake switch 20 is turned on and the auxiliary brake means is operated, and prevents the brake lock of the rear wheel R. Hereinafter, the auxiliary brake control program will be described with reference to FIG.

The controller 14 firstly executes step S3.
At 0, based on the signal from each wheel speed sensor 12,
Calculate the average wheel speed of the front left and right wheels (front wheel side average wheel speed) and the average wheel speed of the rear left and right wheels (rear wheel side average wheel speed), and subtract the rear wheel side average wheel speed from the front wheel side average wheel speed. Then, the wheel speed difference ΔV is obtained. After that, the controller 14 proceeds to step S32 and determines whether or not to reduce the braking force of the auxiliary braking means based on the wheel speed difference ΔV.
Specifically, when the wheel speed difference ΔV is larger than the predetermined value A (ΔV> A), the controller 14 starts this control and reduces the braking force of the auxiliary braking means.

Here, the wheel speed difference ΔV is equal to or less than a predetermined value A (Δ
In the case of V ≦ A), the rear wheel R that is affected by the braking force of the auxiliary braking means and the front wheel F that is not affected by this braking force are rotating in substantially the same manner, and the rear wheel R is brake locked. Not considered. Therefore, in this case, it can be determined that the braking force of the rear wheel R by the auxiliary braking means is not excessive, and it is not necessary to reduce the braking force of the auxiliary braking means.

Therefore, if the determination result in step S30 is negative (No), it is preferable to maintain the braking force of the auxiliary braking means, and the controller 14 returns to step S30 and repeats steps S30 and 32. On the other hand, the wheel speed difference ΔV is larger than the predetermined value A (A <
In the case of ΔV), the rear wheel side average wheel speed is significantly smaller than the front wheel side average wheel speed, and it is considered that the rear wheel R tends to be brake-locked. Therefore, it can be judged that the braking force of the rear wheel R by the auxiliary braking means is excessive, and in this case, it is necessary to limit the operation of the auxiliary braking means to reduce the braking force. Generally, when a so-called empty truck is traveling on a low μ road, the rear wheel R, which is a driving wheel, is easily brake-locked. If the wheel speed difference ΔV is larger than the predetermined value A, and thus the determination result of step S32 is affirmative, the controller 14 determines that the step S34
Proceed to.

In step S34, the controller 1
4 determines the release level n according to the value of the wheel speed difference ΔV. For example, when the value of the wheel speed difference ΔV is larger than the predetermined value A and equal to or smaller than the predetermined value B (A <ΔV ≦ B), the release level n is set to the value 1. Further, when the value of the wheel speed difference ΔV is larger than the predetermined value B and equal to or smaller than the predetermined value C (B
For <ΔV ≦ C), the release level n is set to the value 2.
Further, when the value of the wheel speed difference ΔV is larger than the predetermined value C (C <ΔV), the release level n is set to the value 3. If the brake lock tendency of the rear wheel R is strong, the wheel speed difference ΔV also increases, so the release level n is set according to the strength of the brake lock tendency of the rear wheel R.

After this, the controller 14 proceeds to step S3.
In step 6, the operation of the auxiliary brake means is released according to the release level n. For example, when the release level n is set to the value 1, only the operation of the electromagnetic retarder unit 17 is released and the operations of the exhaust brake unit 16 and the power retard unit 18 are maintained. When the release level n is set to the value 2, the operation of the power retard unit 18 in addition to the electromagnetic retarder unit 17 is released, and the operation of the exhaust brake unit 16 is maintained. Further, when the release level n is set to the value 3, the electromagnetic retarder unit 17 and the power retard unit 18
In addition to this, the operation of the exhaust brake portion 16 is also released, and therefore, the operation of all the auxiliary braking means is released. As a result, the magnitude of the braking force of the entire auxiliary braking device can be set according to the release level n. Table 1 shows the relationship between the wheel speed difference ΔV, the release level n, and the auxiliary braking means.

[0018]

[Table 1] The order of releasing the operation of the auxiliary braking device according to the release level n is not limited to this order. Also,
Only one of the exhaust brake unit 16, the electromagnetic retarder unit 17, and the power retard unit 18 may be operated depending on the release level n. In this case, it is desirable to consider the magnitude relationship of the braking forces of the exhaust brake unit 16, the electromagnetic retarder unit 17, and the power retard unit 18.

Next, the controller 14 carries out step S38.
Then, the pilot lamp 21 is turned on. As a result, the driver can know the decrease in the braking force of the auxiliary braking means by the controller 14. After that, the controller 14 proceeds to step S40 and determines whether or not to end this control program. Controller 1
4 ends this control program when the service brake device is activated, when the vehicle is stopped, and when the operation of the auxiliary brake device 10 is released.

Here, when the controller 14 receives the ON signal from the brake pedal switch 22,
Recognize the operation of the service brake system. Further, the controller 14 controls the vehicle when the signal from the wheel speed sensor 12 attached to the front wheel F that is not affected by the auxiliary brake device 10 has a value of 0 (or a value sufficiently close to 0). Recognize a stop. Furthermore, the controller 14
Recognizes the release of the operation of the auxiliary brake device 10 when the auxiliary brake switch 20 is turned off.

If the determination result in step S40 is negative, the controller 14 proceeds to step S42. Then, in step S42, the wheel speed difference ΔV is recalculated by the same method as in step S30, and then the controller 14 returns to step S34. On the other hand, in step S40,
When any of the conditions is satisfied and the determination result is affirmative, the controller 14 ends the execution of this control program.

In the present embodiment, step S3
The wheel speed difference ΔV is calculated at 0 and 42, and this wheel speed difference ΔV
In step S32 based on V, the control start is determined,
Although the release level n is determined in step S34,
The present invention is not limited to this. For example, the control start may be determined in step S32 based on the deceleration difference ΔG, and the release level n may be determined in step S34.
In this case, the controller 14 performs steps S30 and S42.
At the same time, the rotation deceleration of each wheel is obtained based on the signal from each wheel speed sensor 12, and the average deceleration of the rear left and right wheels is subtracted from the average rotation deceleration of the front left and right wheels to obtain the deceleration difference ΔG. Good.

In this embodiment, when the auxiliary brake switch 20 is turned on, the controller 14
Is configured to start the execution of the auxiliary brake control program, but is not limited to this. For example, if a cancel switch (not shown) is provided in the driver's seat and the driver turns on the cancel switch, the controller 14 controls the auxiliary brake control even if the auxiliary brake switch 20 is turned on. It may be configured such that the program is not executed.

Further, in this embodiment, the auxiliary brake device 10 is provided with the dedicated pilot lamp 21, but the pilot lamp 21 may be omitted. In this case, it is desirable to also serve as another pilot lamp arranged in the driver's seat, for example, a vehicle equipped with an ASR (anti-spin regulator) device that does not operate simultaneously with the auxiliary brake device 10. In, it is desirable to utilize an ASR lamp. At this time, it is desirable to turn on the ASR lamp while the ASR device is operating, and to blink the ASR lamp in step S38 of FIG.

[0025]

As described above, according to the present invention, auxiliary braking means for reducing the driving force of the driving wheels, first and second detecting means for detecting the rotational states of the driving wheels and the non-driving wheels, When the difference between the signal value supplied from the first detecting means and the signal value supplied from the second detecting means is larger than a predetermined value, it is judged that the braking force of the driving wheels by the auxiliary braking means is excessive. An auxiliary braking device for a vehicle is provided with a controller for reducing the braking force of the auxiliary braking means. Therefore, even if the vehicle is running on a low μ road in an empty state, it is possible to prevent the brake lock of the drive wheels by the auxiliary brake device.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of an auxiliary brake device for a vehicle according to the present invention.

FIG. 2 is a flow chart of an auxiliary brake control program executed by the controller 14 of FIG.

[Explanation of reference numerals] 10 auxiliary brake device 12 wheel speed sensor 14 controller 16 exhaust brake unit 17 electromagnetic retarder unit 18 power retard unit F front wheel R rear wheel

Claims (1)

[Claims] 1. An auxiliary braking means for reducing the driving force of a driving wheel, first and second detecting means for detecting rotational states of a driving wheel and a non-driving wheel, and a signal value supplied from the first detecting means. A controller that determines that the braking force of the driving wheels by the auxiliary braking device is excessive when the difference from the signal value supplied from the second detecting device is larger than a predetermined value, and reduces the braking force of the auxiliary braking device. An auxiliary brake device for a vehicle, comprising: