JP2519895B2 - Anti-lock control method - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention is for a vehicle that is equipped with a cross-pipe type two-system braking device and that is capable of switching the drive system between two-wheel drive and four-wheel drive. Anti-lock control method for locking the rear differential of the vehicle, thereby ensuring high braking efficiency, particularly when the vehicle enters an anti-skid control state on a split μ road surface during four-wheel drive Regarding the method.

[Background of the Invention]

In the vehicle equipped with the cross piping type two-system braking device as described above and capable of switching the drive system between the two-wheel drive and the four-wheel drive, all the wheels are directly connected to the drive system during the four-wheel drive. Therefore, it is difficult to lock the vehicle, but in an anti-skid control device for such a vehicle, this vehicle is usually driven by four wheels, for example, the left wheel has a high μ side and the right wheel has a low μ side split. When traveling on μ road surface, when the rear wheels on the low μ road surface are about to lock, antilock control is performed based on that, so the brakes are loosened too much and braking efficiency decreases. There is a problem that it will end up.

[Object of the Invention]

The present invention is an anti-lock control method for a vehicle equipped with a cross piping type two-system braking device and capable of switching the drive system between two-wheel drive and four-wheel drive. When the vehicle enters the anti-skid control state while traveling on the split μ road surface by four-wheel drive, the rear differential of the vehicle is locked to avoid the above-mentioned problem, and thus high braking efficiency can be secured. An object is to provide an antilock control method.

[Structure of Invention]

According to the antilock control method of the present invention, when the vehicle enters the antilock control state while traveling on the split μ road surface by four-wheel drive, a signal indicating that the vehicle is traveling on the split μ road surface is provided. , And a signal indicating that the anti-skid control state has been entered, and the rear differential of the vehicle is locked based on these signals.

〔The invention's effect〕

When the anti-lock control state is entered while traveling on the split μ road surface with four-wheel drive, the left and right rear wheels are accelerated and decelerated simultaneously by locking the rear differential, ensuring high braking efficiency. can do.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

First, referring to FIG. 1, there is shown a braking device to which the present invention is applied. In this figure, FR, FL, RR, RL
Are front right wheel, left front wheel, right rear wheel, left rear wheel, 1a and 1b are front axle, rear axle, 2a and 2b are front differential and rear differential.
3 is brake petal, 4 is master cylinder, 5 _FR ,
5 _FL , 5 _RR , and 5 _RL are the front right wheel FR, left front wheel FL, and right rear wheel R, respectively.
R is a wheel cylinder of the brake device for the left rear wheel RL. This brake system is equipped with a right front wheel cylinder 5 _FR
And the left rear wheel wheel cylinder 5 _RL are connected via a pipe 6a, and the left front wheel wheel cylinder 5 _FL and the right rear wheel wheel cylinder 5 _RR are connected via a pipe 6b. ing.

Further, in FIG. 1, 7 _FR , 7 _FL , 7 _RR , and 7 _RL are wheel speed detectors (speed sensors) provided in association with the right front wheel FR, the left front wheel FL, the right rear wheel RR, and the left rear wheel RL, respectively. ), And
These speed sensors input detection information to the control circuit 8. The control circuit 8 can be generally constructed by using a microcomputer, and in this embodiment, the control circuit 8 is provided with the components shown in the chain line block 8 in FIG. 2 or FIG. 3, respectively. Can be configured as one. Reference numerals 9a and 9b each include a gate valve, a pressurizing valve, a depressurizing valve, etc., and are known modulators that control increase / decrease in brake pressure. Piping 6a connecting _FR and left rear wheel wheel cylinder 5 _RL
The left front wheel wheel cylinder 5 _FL and the right rear wheel wheel cylinder 5 _RR are connected to a pipe 6b. These modulators 9a and 9b are
Controlled by a signal from the control circuit 8, each wheel cylinder performs an operation such as pressurization, depressurization or pressure retention.

In this embodiment, the rear differential lock signal generating circuit 10 to which the control circuit 8 and the speed sensors 7 _RR and 7 _RL for the right rear wheel and the left rear wheel are connected when the four wheels are driven, and the signals from this circuit are used. In response, an actuator 11 for locking the rear differential 2b is provided.
Further details will be described later with reference to FIGS. 3, 3 and 4. The rear differential lock signal generating circuit 10 provided according to the present invention is connected to the control circuit 8 and the speed sensors 7 _RR and 7 _RL only when the four wheels are driven as described above.
It is configured so as to be separated from them during wheel drive. In practice, when the vehicle drive system is switched to four-wheel drive, the circuit 10 is connected as described above in response to the two-wheel drive. Switching means is provided which operates to disconnect the circuit 10 in response to switching to drive, but such switching means has been omitted from the drawing for simplicity of illustration. It should be noted that each of FIGS. 3 to 3 shows the configuration at the time of four-wheel drive.

FIG. 2 shows one embodiment of the present invention, and the portions corresponding to FIG. 1 are designated by the same reference numerals as those in FIG.
In this embodiment, the control circuit 8 described above is composed of row select circuits 12a and 12b and logic circuits 13a and 13b connected to the row select circuits 12a and 12b, respectively.
Right front wheel speed sensor 7 _FR and left rear wheel speed sensor 7
_The left front wheel speed sensor 7 _FL and the right rear wheel speed sensor 7 _RR are connected to the other row select circuit 12b. Logic circuits 13a and 13b are connected to the output sides of the row select circuits 12a and 12b, and these logic circuits 13a and 13b are connected to modulators 9a and 9b, respectively.

Further, in this embodiment, the above-described rear differential lock signal generation circuit 10 includes a comparator 14 to which the left rear wheel speed sensor 7 _RL and the right rear wheel speed sensor 7 _RR are connected, and the output side of the comparator 14. , A flip-flop circuit 16 to which the trigger signal generator 15 is connected to the set terminal S, an OR gate 17 to which outputs of the logic circuits 13a and 13b are connected, and this OR gate. A timer circuit 18 connected to the output side of 17 (this timer circuit will be described later), and an AND gate 1 connected to the output side of the timer circuit 18 and the flip-flop circuit 16.
9 and a trigger signal generator 21 connected to the output side of the timer circuit 18 via an inverter 20 and connected to the reset terminal R of the flip-flop circuit 16 on the output side.

When the vehicle is driven by four wheels, the so-called split μ road surface in which the upper side is a low μ road surface and the lower side is a high μ road surface, for example, as shown in FIG. It is assumed that the wheels FR and RR are traveling on a low μ road surface and the left wheels FL and RL are traveling on a high μ road surface.

In such a state, when the brake is applied and the right front wheel FR on the low μ road surface is about to be locked, the pressure reducing signal S ₁ is obtained at the output side of the logic circuit 13a in FIG. 2, and thereby the modulator 9a is obtained. Is controlled, right front wheel FR
-The system of the left rear wheel RL enters the anti-skid control state. Then, the reduced pressure signal S ₁ is given to one input terminal of the OR gate 17, and no signal is given to the other input terminal of the OR gate 17 (the system of the left front wheel FL-the right rear wheel RR is anti-lock). When the skid control state is entered, the pressure reduction signal S ₂ is given from the logic circuit 13b), the OR gate 17 is turned on, and its output is given to the timer circuit 18, whereby the output side of the timer circuit 18 is given. The signal S ₃ is obtained. In this case, the timer circuit 18 is configured so that the output signal S ₃ is generated for a slightly longer time than the generation cycle of the pressure reduction signal S ₁ or S ₂ .

At the same time, as shown in FIG. 2, the signals from the left rear wheel speed sensor 7 _FR and the right rear wheel speed sensor 7 _RR are compared in the comparator 14, whereby the vehicle runs on the split μ road surface. Is detected, a signal resulting from this detection is applied to the trigger signal generator 15, the trigger signal is applied to the set terminal S of the flip-flop circuit 16, and an output signal is obtained from the flip-flop circuit 16. The flip-flop circuit 16 thus obtained
Is a signal indicating that the vehicle is currently traveling on the split μ road surface as described above, and this output signal indicates that the vehicle brake device has entered the anti-skid control state as described above. The output signal S ₃ from the timer circuit 18 is simultaneously given to the two input terminals of the AND gate 19, whereby the AND gate 19 is turned on and its output signal is given to the actuator 11, and the rear differential 2b is turned on. Locked. In this case, the locked state of the rear differential 2b is to be maintained during the output signal S ₃ of the timer circuit 18 is alive will be apparent.

When the rear differential 2b is locked in this manner, the right rear wheel RR on the low μ road surface is rotated on the left rear wheel RL side, so that sudden deceleration does not occur. Also, as mentioned above, at this point, the left front wheel
Since the FL-right rear wheel RR system does not control the pressure reduction, the rear axle maintains the braking force, but when the braking force further increases, the FL-RR system also enters the anti-skid control state. As described above, according to the present invention, the split μ is generated when the vehicle is driven by four wheels.
When traveling on the road surface, the control cannot be decided only on the low μ road side, so that high braking efficiency can be secured even on the split μ road.

In such a state, when the output signal S ₃ from the timer circuit 18 disappears, a trigger signal is generated at the output side of the trigger signal generator 21 by the action of the inverter 20, and the trigger signal is generated by the flip-flop circuit 16 Reset terminal R
As a result, the AND gate 19 is turned off, and the actuator 11 unlocks the rear differential 2b to make it free.

FIG. 3 shows another embodiment of the present invention, which is different from the embodiment of FIG. 2 described above only in the portion A ′ surrounded by the dotted line, and the other construction. Since the operation and the operation and the effects obtained thereby are the same as those in the case of FIG. 2, the parts corresponding to those of FIG. 2 in the embodiment of FIG. Is omitted. A portion A surrounded by a dotted line in FIG. 2 is composed of two row select circuits 12a and 12b, but in FIG. 3, a portion A'correspondingly surrounded by a dotted line is shown. Is composed of three row select circuits 22a, 22b, 22c.
2a left rear wheel speed sensor 7 _RL and right rear wheel speed sensor 7
_RR is connected, the output side of this row select circuit 22a is connected to the other two row select circuits 22b and 22c, and at the same time, these two row select circuits 22b and 2b are connected.
The right front wheel speed sensor 7 _FR and the left front wheel speed sensor 7 _FL are connected to 2c, respectively, and the outputs of the row select circuits 22b and 22c are connected to the logic circuits 13a and 13b, respectively.

Although the specific embodiment of the present invention has been described above, the present invention is not limited to that. The point is that when an antilock control state is entered while traveling on a split μ road surface during four-wheel drive. It should be understood that any structure can be used to lock the rear differential, and thus any such structure is within the scope of the present invention.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an example of a vehicle brake device to which the present invention is applied, FIG. 2 is a block diagram showing one embodiment of a configuration capable of carrying out the method of the present invention, and FIG. FIG. 4 is a block diagram showing an embodiment, and FIG. 4 is a diagram for explaining the present invention. In the drawing, FR is the right front wheel, FL is the left front wheel, RR is the right rear wheel,
RL is the left rear wheel, 1a is the front axle, 1b is the rear axle, 2a is the front differential,
2b is a rear differential, 3 is a brake pedal, 4 is a master cylinder, 5 _FR , 5 _FL , 5 _RR and 5 _RL are wheel cylinders, 6a and 6b are cross pipes, 7 _FR , 7 _FL , 7 _RR and 7 _RL are speed sensors. , 8 is a control circuit, 9a and 9b are modulators, 10 is a rear differential lock signal generating circuit, and 11 is an actuator.

Claims (1)

(57) [Claims] 1. An anti-lock control method for a vehicle, comprising a cross pipe type two-system braking device and capable of switching a drive system between two-wheel drive and four-wheel drive, when four-wheel drive is performed. When the anti-lock control state is entered on the split μ road surface, the rear differential of the vehicle is locked based on a signal indicating the split μ road surface and a signal indicating the anti-lock control state. And anti-lock control method.