JPS62275869A - Anti-skid control method - Google Patents

Abstract

PURPOSE:To shorten a braking distance by making a comparison between the front and rear wheels of each system in speed so as to hold braking pressure to the rear wheel when the front wheel is lower than the rear wheel in speed beyond a predetermined value whereby assuming an anti-skid control only on the front wheel. CONSTITUTION:When the brake is applied while a vehicle is running, output signals from speed sensors 15FR and 15RL which detect the rotating speed of a right front and a left rear wheel in one of two cross piping type brake systems, are compared with each other by a comparator 107, thereby obtaining a difference S between said two signals by a subtracter 108. Then, said difference signal is compared with a predetermined difference in wheel speed DELTAV by a comparator 109 wherein a solenoid valve 102a is blocked in case of S>DELTAV through a FF circuit 110 and a driving circuit 111, thereby cutting off braking pressure to the rear wheel. And the moving contact 104a of a changeover switch 104 is changed over to a stationary contact 104c, thereby assuming an anti-skid control only on the front wheel based on front wheel speed.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention [Field of Application of the Invention] The present invention relates to a cross piping system in which anti-skid control is performed based on select lows between front wheels and rear wheels in each system. Regarding an anti-skid control method for a vehicle equipped with a dual-system anti-skid control brake system, the brake pressure is maintained on the rear wheels and the front wheels are The present invention relates to an anti-skid control method that performs anti-skid control based on the front wheel speed only when the vehicle is in use, thereby making full use of the brake pressure of the front wheels and also making use of the braking force of the rear wheels.

[Background of the invention]

In a vehicle equipped with the above-mentioned cross-piped dual-system anti-skid control brake system, the front and rear wheels of each brake system (
When controlling the diagonal) at the same time with select low, normally,
In a vehicle, the brake force is distributed to the front wheels so that the front wheels lock first, but if the anti-skid operates so that the rear wheels lock before the front wheels (rear wheel pre-lock), the front wheels will lock. Braking distance may be longer because the brake force is not fully utilized.

[Purpose of the invention]

Therefore, the present invention maintains the brake pressure on the rear wheels when the rear wheels tend to lock earlier than the front wheels, performs anti-skid control only on the front wheels based on the front wheel speed, and brakes the front wheels. The purpose of the present invention is to provide an anti-skid control method that effectively avoids the above-mentioned problem of increasing braking distance by making full use of the braking force of the rear wheels as well as the braking force of the rear wheels. shall be.

[Structure of the invention]

In the anti-skid control method of the present invention, in the above-mentioned cross-piped dual-system anti-skid control brake device,
When the rear wheel speed of either system decreases by more than a predetermined value than the front wheel speed due to the operation of the brake system,
Brake pressure to the rear wheels is cut off and maintained, and anti-skid control is performed only on the front wheels based on the front wheel speed.

[Effects of the Invention] According to the present invention, even if the rear wheels tend to lock earlier than the front wheels, the braking force of the front wheels can be fully utilized, and the braking force of the rear wheels can also be utilized. You can make use of it.

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

FIG. 1 schematically shows the configuration of an example of an anti-skid control device to which the present invention can be applied.
) ``Rake pedal, 2 is the mask cylinder, 3 is the wheel,
4 is a wheel brake device wheel cylinder, 5 is a gate valve, 6 is a solenoid valve device for both pressurization and holding (hereinafter referred to as a pressurizing valve), 7 is a TM valve device for pressure reduction (hereinafter referred to as a pressure reducing valve), 8 is from the mask cylinder 2 to the gate valve 5
and a main path for transmitting brake hydraulic pressure connected to the wheel cylinder 4 of the wheel brake device via the pressurizing valve 6.

The gate valve 5 has a cylinder 10.11 containing a differential pressure moving piston 9, and closes the valve 12 portion of the gate when moved to the left in the figure due to the differential pressure. When the valve 12 closes, the mask cylinder side and the foil cylinder side are pressure-blocked.

13 is a check valve, and 14 is a relief valve.

15 is a wheel speed detector (speed sensor) provided in relation to the wheel 3, and inputs detection information to the control circuit 16. This control circuit 16 is generally configured using a microcomputer, and in this embodiment, it is configured with a control 8 function corresponding to the block diagram shown in FIG. Based on the detection information from the speed sensor 15, the oil pressure holding signal S or the pressure reduction signal S2 is output.

The pressurizing valve 6 is of a normally open type, and is switched to the closed state by the hydraulic pressure holding signal S from the control circuit 16, thereby blocking the main path 8 (setting the hydraulic pressure holding state).
The reduced pressure Pal furnace is a normally closed type, and is switched to the open state by the reduced pressure signal St from the control circuit 16, and pressurized oil in the foil cylinder 4 is pumped up to the pressure accumulator 19 via the reservoir 17 and pump 18, and the gate valve 5 It is connected to a bypass path 20 so as to return this pumped up pressure oil between the pressurizing valve 6 and the pressurizing valve 6.

In the above, in order to simplify illustration and explanation,
I mentioned the system related to two wheels, but in reality,
A similar system is associated with each wheel,
Furthermore, according to the present invention, each of these systems is related to each other in a unique B manner as described below.

Fig. 2 is a diagram for explaining the piping system of a brake device to which the present invention is applied, Fig. 3 is a block diagram showing an example of a configuration in which the method of the present invention can be implemented, and Fig. 4 is a detailed diagram of the present invention. It is a figure for explaining. In Figures 2 and 3, parts corresponding to those in Figure 1 are indicated by the same symbols, and in these figures, FR is the right front wheel, FL is the left front wheel, and RR is the right rear wheel. , RL indicates the left rear wheel,
And when those letters are used as subscripts, they indicate that they are related to the respective wheels.

In FIG. 2, 15F, 15. 15111I
and 15. LL are speed sensors, respectively.

100a and 100b are modulators each including the gate valve, pressurization valve, pressure reduction valve, etc. described above with respect to FIG.
and wheel cylinders 4Fl and 411L of the brake device for the left rear wheel RL via pressure oil piping 101a, while the modulator 100b is connected to the left front wheel F
It is connected via a pressure oil pipe 101b to wheel cylinders 4FL and 4□ of a brake device for the L and right rear wheels RR. That is, the brake device shown in FIG. 2 has a cross-piped configuration. In such a configuration, according to the present invention, solenoid valves 102a and 102b are provided between the modulator 100a and the foil cylinder 4*L and between the modulator 100b and the foil cylinder 4□ of the pressure oil pipes 101a and 101b, respectively. These solenoid valves IQ2a and 102b are actuated by signals from the control circuit 16, as shown in FIG. 3, which will be explained in detail later with reference to FIG. As such, in the present invention, the above-described control circuit 16 includes a control circuit section 16a provided for the right front wheel and left rear wheel system, and a control circuit section provided for the left front wheel and right rear wheel system. 16b, and these recontrol circuit parts have the same circuit configuration, so in FIG. The details of the configuration of only one control circuit portion 16a are shown, and the other control circuit portion 16b is omitted for the sake of brevity. In FIG. 3, as described above, the parts corresponding to FIG. 1 are indicated by the same reference numerals, and the parts corresponding to FIG. 2 are also indicated by the same reference numerals.

First, a low select circuit 103 is provided, and a right front wheel speed sensor 15□ and a left rear wheel speed sensor 1511L are connected to a pair of inputs of this low select circuit 103, and the output side thereof will be explained in detail later. It is connected to a logic circuit 105 via a changeover switch 104. The outputs of this logic circuit 105 are connected to a holding pressure drive circuit 106a and a pressure reduction drive circuit 106b, respectively. Note that the changeover switch has one movable contact 104.
a, and two fixed contacts 104b and 104C, and as shown in the figure, the output of the low select circuit 103 is connected to the fixed contact 104b, and the other fixed contact 104C is connected to the speed sensor 15□. has been done.

Further, normally, the movable contact 104a is engaged with the fixed contact 104b.

Furthermore, a comparator 1.07 is provided, on the input side of this comparator speed sensors 15□ and 15. 1L is connected, and a subtracter 10 connected to the speed sensors I5□ and 15-L is connected to the output side.

The output of the subtractor 108 is connected to one input terminal of a comparator 109, the other input terminal of which is provided with a signal ΔV representing a predetermined wheel speed difference.

The output of the comparator 109 is connected to the cent terminal S of the flip-flop circuit 110.
The output terminal 0 is connected to the drive circuit 111 for the solenoid valve 102a described above. A voltage reduction drive circuit 10 is connected to the recent terminal R of the flip-flop circuit 110.
Off l-IJ gas generator 1 operated by the output of 6b
12 are connected.

The above explanation is about the control circuit section 16a for the front right wheel and rear left wheel system, but the control circuit section 16b for the front left wheel and rear right wheel system is configured in exactly the same way. , it should be understood that the operations described below are exactly the same.

Next, looking at the operation, the brake is turned on at time L1 as shown in Figure 4E, and the front wheel speed and rear wheel speed are as shown by curves ■ and ■ in Figure 4A, respectively. Suppose that the value decreases to . In this case, the signals representing the speeds from the speed sensors 15□ and 15*L are compared in the comparator 107, and based on this, the signal representing the rear wheel speed is subtracted in the subtractor 108 from the signal representing the front wheel speed. , the output of the subtractor 10, that is, the difference S between these two signals, is compared with the signal Δ■ representing the above-mentioned predetermined wheel speed difference in the comparator 109. If the difference S becomes larger than Δ■, comparator 1
An output signal appears on the output side of 09, this output signal is given to the set terminal S of the flip-flop circuit 110, and as a result, an output signal is obtained at the output terminal Q of this flip-flop circuit 110, and this output signal is driven. is applied to circuit 111 so that, as shown in FIG. 4B,
The solenoid valve 102a is closed for the above-mentioned time of 1°,
Brake pressure to the rear wheels is canted and maintained. At the same time, due to the effect of the output of the drive circuit 111, the third
As indicated by a dotted line 113 in the figure, the movable contact 104a of the changeover switch 104 is switched from the fixed contact 104b to 104C, and anti-skid control is performed only for the front wheels based on the front wheel speed. Figures 4C and 4D illustrate the operation of this anti-skid control.
Figure C illustrates the on/off state of the pressurization/holding valve in the modulator 100a, and the figure C illustrates the on/off state of the pressure reducing valve in the modulator. In the case of FIG. 4, the solenoid valve 102a is activated at the time tz, t7 when the rear wheel speed becomes lower than the front wheel speed by Δ■.
When the front wheel speed increases by, for example, 15% from the low peak, 14.1. Turn off the solenoid valve 1.
While 02a is on, the brake pressure for the rear wheels is cut off from the mask cylinder 2 and held, and anti-skid control is performed only for the front wheels based on the front wheel speed as shown in FIGS. 4C and D. It is possible.

[Brief explanation of drawings]

FIG. 1 is a diagram schematically showing the configuration of an example of an anti-skid control brake device to which the present invention can be applied, FIG. 2 is a diagram for explaining the piping system of the brake device to which the present invention is applied, and FIG. 4 is a block diagram showing an example of a configuration capable of implementing the method of the present invention, and FIG. 4 is a diagram for explaining the present invention in detail. In the drawing, 1 is a brake pedal, 2 is a mask cylinder, FR, FLSRR, RL are front right wheel, front left wheel, rear right wheel, rear left wheel, 4□, 4. 4-14, is a foil cylinder,
15□, 15. 15*x-15-t is a speed sensor, 16 is a control circuit, 100a and 100b are modulators, and 101a. 101b is a cross pipe, 102a and 102b are solenoid valves, 103 is a low select circuit, 104 is a changeover switch, 105 is a logic circuit, 106a is a pressurization/holding drive circuit, 1.06b is a pressure reduction drive circuit, and 107 is a comparator. , 108 is a subtracter, 109 is a comparator, 110 is 797.
17071 circuit, 111 is a drive circuit, and 112 is an off-trigger generator.

Claims (1)

[Scope of Claims] Anti-skid control for a vehicle equipped with a cross piping type two-system anti-skid control braking device in which anti-skid control is performed based on the select low of front wheels and rear wheels in each system. In the method, the front wheel speed and rear wheel speed of the system are compared, and if the rear wheel speed becomes lower than the front wheel speed by a predetermined value or more, the brake pressure for the rear wheels is maintained and the brake pressure is applied only to the front wheels based on the front wheel speed. An anti-skid control method characterized by performing anti-skid control using