JPS5849418B2 - Anti-slip handshake - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an anti-skid device for a vehicle in which a plurality of wheel axles are arranged close together.

For example, if a vehicle has three or more wheel axles, the front two
The present invention relates to an anti-skid device for a semi-trailer equipped with an axle or two rear axles close to each other, or a semitrailer with multiple axles and equipped with a plurality of closely spaced wheel axles.

In general, the brake friction coefficient fb and side friction coefficient fs between the wheels and the road surface are determined by the wheel slip rate S (vehicle speed is
If the wheel circumferential speed is Wv, then S(V b − Wv )
÷vb) as shown in FIG.

In other words, the brake friction coefficient fb is maximum at around S = 0.2 and becomes considerably small at S-1 (stuck wheel), and the side friction coefficient fs is highest at S-O and decreases as S increases.
-I becomes almost O.

The way the friction coefficients fb and fs change with respect to the slip rate is as follows:
It hardly changes even if the road surface condition changes.

Therefore, it is best to control the wheels by anti-skid by adjusting the brake pressure so that S=0.2 is always maintained, to maintain the brake force near the maximum, and to also maintain sufficient side force, that is, steering force and force to prevent irregular turns. Optimal.

Even in anti-skid devices for vehicles equipped with multiple wheel axles that are close together, differences in the brake friction coefficient fb and side friction coefficient fs between the wheels and the road surface for each wheel, and differences in the vehicle movement toward the front wheels during braking are considered. In terms of performance, it is best to perform anti-skid control independently for each wheel because of the movement of the center of gravity and the movement of the center of gravity to the outer wheels due to centrifugal force generated during braking when turning.

However, this requires a wheel rotational speed detector, a wheel speed detector, a control circuit, and a brake pressure controller for each wheel, which is uneconomical.

To deal with this, a wheel speed detector is provided for each wheel, and the wheel speed is integrated at each wheel axle using a selection circuit, and a control circuit and brake pressure controller are provided for each wheel axle to control the wheel speed. law is being practiced.

This method is economical because the control circuit and brake pressure controller are halved.

However, in this case, since the axis control is controlled for each wheel axle, the front and rear axles are independently controlled for the load movement in the front and rear force direction during braking, and the changes can be adequately coped with. When road conditions differ between the left and right sides of the vehicle, for example when one wheel is on concrete and the other wheel is on frozen ice on the shoulder, one brake pressure controller is used for both left and right wheels for each wheel axle. It is not good in terms of performance to control with

In other words, if the speed of the wheel with the higher force among the left and right wheels is input to the control circuit, the wheel with the higher force and the wheel speed will be sufficiently controlled;
A wheel with low wheel speed and force (a wheel whose slip rate is increasing and becoming stuck) becomes stuck because its brake pressure becomes inappropriately large.

Also, if the wheel speed of the left and right wheels with the lower force is input to the control circuit, the wheel with the lower force will be adequately controlled, but the brake pressure of the wheel with the higher wheel speed will be less suitable for the lower wheel speed. Since it is controlled by brake pressure, sufficient brake pressure cannot be applied, resulting in insufficient braking force.

Therefore, the present invention provides a wheel speed detector for each of the approaching multi-axle wheels of a vehicle, integrates the signals on the left and right sides, and uses one control circuit and brake pressure controller for each of the left and right sides. The object of the present invention is to provide an economical anti-skid device that has performance equivalent to independent control of each wheel by independently controlling the left and right wheels.

The following is a second example of the semi-trailer in which the present invention is implemented.
This will be explained with reference to FIG.

1 is a tractor and 2 is a semi-trailer, which are frozen by a coupler 3.

The semi-trailer 2 has wheels 5, 6 close to each other on its right side, and wheels 7, 8 on its left side symmetrically.

A relay valve 4 discharges pressure fluid corresponding to the pressure in the brake pipe 9 from the pressure vessel 10 to the brake pipe 11 when the brake is applied.

12 is a brake pressure controller for the right wheel, and 13 is a brake pressure controller for the left wheel, which respectively includes a relay valve 4 and right wheels 5, 6,
Each wheel brake actuator 35, 3B for the left wheels 7, 8,
37 and 38, and repeatedly releases, maintains, and releases the pressure of the brake actuators on each side to control the brake pressure against skid.

Detectors 14, 15, 16, 17 are connected to the respective wheels 5, 6.
, 7, and 8, and generates an AC output with a frequency proportional to the wheel speed of each wheel.

Reference numeral 18 denotes a control circuit, which includes all of the converter, selection circuit, and control logic circuit described later, and which is connected to each of the detectors 14 to 17.
The output of the brake L/-key pressure controllers 12, 13 {G
Sends control signals to independently release, maintain, and apply brake pressure.

19, 20, 21, 22 are converters, and each detector 1
4, 15, 16, 17, each wheel 5, 6, 7.8
converts into DC output according to the wheel speed.

The combination of the detector and its converter constitutes a wheel speed detector.

Selection circuits 23 and 24 select the outputs of converters 19 and 20, 21 and 22, respectively.

There are two types of selective force methods: one uses the wheel speed with the lower force of two people, and the other uses the wheel speed with the higher force, but in the former case, rotation of both wheels is ensured. However, if there is a difference in the coefficient of friction between the wheels and the road surface between the two wheels, or a difference in the load applied to the wheels between the two wheels, the wheel speed will be controlled by a lower force braking pressure. Braking force is insufficient for high speed forces.

In addition, when a high force wheel speed is used, the force at a low wheel speed causes the brake pressure to become inappropriately large and become stuck, and only one wheel can be effectively controlled.

However, even if one wheel becomes stuck, the other wheel is effectively controlled, so there is no loss of brake power.

Another selective force method is a force method that uses the average of both inputs, but when one force of two people advances to fixation, the change appears as 100, but the change in wheel speed is detected. Other than being able to do this, it is essentially the same as using force at a low wheel speed.

In the present invention, for reasons explained later, there is almost no difference in friction coefficient or load between the two input wheels. I use it.

Control logic circuits 25 and 26 calculate the outputs of the respective selection circuits 23 and 24, and release or maintain the brake pressure under certain conditions to prevent skidding.
A signal such as "loading" is sent to the electromagnetic solenoids 27 and 28 of the brake pressure controllers 12 and 13 to control the brake pressure controllers 12 and 13, respectively.

Each element of the configuration described above is known from Japanese Patent Application Laid-Open No. 49-44195, Japanese Patent Publication No. 49-33640, etc., and detailed explanation thereof will be omitted.

Next, the effects of using the present invention will be described.

Since anti-skid control is performed by integrating the wheels on each side, it is possible to prevent differences in road surface conditions between the right wheels 5, 6 and the left wheels 7, 8, as well as damage to the outside wheels due to centrifugal force during turning braking. In order to deal with differences in load caused by movement of the center of gravity, etc., the right wheels 5, 6 and the left wheels 7, 8 are controlled separately, that is, the right wheels 5, 6 are controlled by one brake pressure controller 12, and the right wheels 5, 6 are controlled separately. By controlling the left wheels 7 and 8 with one brake pressure controller 13, each wheel can be well controlled.

In addition, when the condition of the longitudinal force direction of the vehicle changes, for example, when the brake road surface changes from a high friction coefficient to a low friction coefficient, the right wheels 5, 6 and the left wheels 7, 8 are close to each other, so there is friction between the front and rear wheels. The time it takes to travel across road surfaces with different coefficients is very short, and the impact on overall braking performance is negligible.

Furthermore, even if the load changes in the longitudinal force direction due to a shift in the center of gravity that occurs during braking, the load of the semi-trailer 2 is supported by the wheels 5, 6, 7, and 8 and the coupler 3, and the load of the semitrailer 2 is supported by the wheels 5, 7, and the The distance between the axles 6 and 8 is only 1.2 to 1.5 m compared to the distance of several meters between the wheels and the coupler 3, and most of the load changes in the longitudinal force direction of the vehicle occur between the wheels and the coupler. The load change between the wheels 5, 7 and the wheels 6, 8 is on the order of several φ, and even when a force with a low wheel speed output is input to the control logic circuits 25, 26, the braking force changes. The loss is negligible.

Although the present invention has been described above with respect to a semi-trailer, the present invention can also be applied to a rear wheel axle of a truck equipped with a front wheel axle 30 and close rear wheel axles 31 and 32 shown in FIG. It can also be applied to vehicles with three or more axles.

With the configuration described above, this invention is economical because the number of control logic circuits and brake pressure controllers is halved compared to when each wheel is independently controlled. Since the control is integrated on each side, when the road surface conditions are different on both sides of the vehicle, or when the wheel loads are different on the left and right sides,
Furthermore, even when there is a load shift in the front-rear force direction of the vehicle due to movement of the center of gravity during braking, etc., it is almost unaffected by this and has almost the same performance as when each wheel is independently controlled.

[Brief explanation of the drawing]

Fig. 1 is a diagram of changes in the coefficient of friction between the wheels and the road surface depending on the slip rate, Fig. 2 is a block diagram of the piping and wiring of an embodiment of this invention applied to a semi-trailer, and Fig. 3 is the circuit of its control device. The block diagram, FIG. 4, is a diagram of another vehicle to which the present invention can be applied. fb・・・Brake friction coefficient, fs・・・・・・
Side friction coefficient, S...Slip rate, 1...
・Tractor, 2... Trailer, 3...
Coupler, 4... Relay valve, 5, 6, 7, 8...
... Wheels, 9, 11 ... Brake pipe, 10.
...Pressure vessel, 1 2, 1 3...Brake pressure controller, 14,15,16,17...
Detector, 18... Control circuit, 19, 20, 21
, 22...Converter, 23, 24...
- Selection circuit, 25, 26... Control logic circuit, 2
7, 28... Electromagnetic solenoid.

Claims (1)

[Claims] 1. In a vehicle in which multiple wheel axles are arranged close to each other, a wheel speed detector is provided for each of the left and right wheels in the direction of the traveling force of the wheel axle, and the output of the multiple wheel speed detectors on each side is A control circuit that selects a signal that is less than the average value of the signals and sends a brake pressure control signal corresponding to this selection signal, and a brake that commonly controls the brake pressure of the wheels on each side using the output of this control circuit. An anti-skid device for a vehicle, characterized by comprising a pressure controller.