JPS5930586B2 - Anti-skid device for vehicles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an anti-skid device for a vehicle that controls the braking force of the wheels to an optimum value so as to prevent the wheels from locking when braking the vehicle.

The purpose of this type of anti-skid device is to reduce the speed of the vehicle to prevent the wheels from locking when braking the vehicle, and to prevent loss of steering and irregular turns due to wheel locks caused by excessive braking force. The purpose is to prevent

For this reason, an anti-skid device is generally installed on each axle of a vehicle.

Figure 1 is a configuration diagram of a conventional anti-skid device applied to the pneumatic brake system of this type of large vehicle. , 5.6 are the left and right wheels of the rear axle, γ and 8 are wheel rotation speed detectors attached to the front wheels and detect the rotation speed of the wheels as electrical quantities, and 9 and 10 are wheel rotation speed detectors attached to the middle wheels. , 11, 12 are wheel rotational speed detectors mounted on the rear wheels; 13, 14, 15 are brake chambers that apply braking force to each wheel using pressurized air corresponding to the braking force generated by the brake valve 16; 1γt; 18. 19 (ri
Mitsu Lake Valve 1 and Brake Chambers 13, 14, 1
A braking force control signal generator 2 installed between the
A braking force control device 20 is controlled by an output signal generated at 0°21.22, and the braking force control device 20 uses the wheel rotation speed detectors 7 and 8 as input signals to detect a state in which the front wheels are about to lock. A braking force control signal generator 21 receives the wheel rotation speed detectors 9 and 10 as input signals, detects a state in which the center axle wheel is about to lock, and outputs a braking force control signal to the braking force control device 18. A braking force control signal generator that generates a control signal; 22 is a wheel rotation speed detector 1;
This is a braking force control signal generating device which takes 1.12 as an input signal, detects a state in which the rear wheels are about to lock, and generates a braking force control signal to the braking force control device 19.

In FIG. 1, anti-skid devices are installed independently on three axles, and their operations are all the same, so the operation of the anti-skid device for the front axle will be explained.

First, the wheel rotational speed is inputted as an electrical quantity by the wheel rotational speed detectors 7 and 8 to the braking force control signal generator 20.

When braking a vehicle, the braking force from the pressurized air generated by the brake valve 16 is applied to the wheels via the brake chamber 13, and when the braking force exceeds the pressure due to the frictional resistance between the wheels and the road surface, the wheels experience a large deceleration. Head to the lock.

A braking force control signal generator detects the deceleration of 20 wheels,
When the wheel deceleration exceeds a predetermined value,
A signal is generated to release the braking force, and the braking force control device 17 gradually reduces the braking force. When the deceleration of the wheels decreases due to the decrease in the braking force, and reaches the above-mentioned set value or less, the braking force decreases. and gradually increase the braking force.

By repeating the above operations, it was possible to prevent the wheels from locking during sudden braking, reduce the wheel speed to a slip ratio of around 20 relative to the vehicle body speed, and ensure steering performance and directional stability.

However, installing such a system on every axle of the vehicle has the drawback of being extremely expensive.

Furthermore, if either the center axle or the rear axle attached to the rear of the vehicle is equipped with an anti-skid device and only the rear axle is controlled, sufficient steering performance and directional stability during braking can be ensured, but this is not the case for large freight vehicles. As seen in some vehicles, a vehicle that drives the center axle and rear axle simultaneously, has a differential mechanism installed between the center axle and the rear axle, and has a function to activate and deactivate the differential mechanism from the driver's seat, There were the following problems.

In other words, when the differential mechanism is not operating, the rotation of the engine drive shaft is directly transmitted to the center shaft and rear shaft, so the rotation speed of the center shaft and the rotation speed of the rear shaft are the same, and when the differential mechanism is operating, the driving force is transmitted through the differential mechanism. The rotation speed is transmitted to the center shaft and rear shaft, and the rotation speed proportional to the sum of the center shaft rotation speed and the rear shaft rotation speed becomes the same as the drive shaft rotation speed, so if the anti-skid device on the center shaft is omitted, the differential mechanism will not operate. This may not be a problem, but when the differential mechanism is not operating, the center axle wheel rotation speed and the rear axle wheel rotation speed are the same, so if the center axle wheels lock during sudden braking, the rear axle wheels will also lock at the same time. Even if the braking force on the rear wheels is reduced, wheel locking cannot be prevented.

Furthermore, even if the rear axle anti-skid device is omitted, the rear axle wheel lock will also lock the center axle wheels, making the center axle anti-skid device uncontrollable.

For this reason, in this type of vehicle, it was necessary to install an anti-skid device on each axle.

The present invention solves the above-mentioned drawbacks, and provides a device that can control the anti-skid device regardless of whether the differential mechanism is activated or not, and can reduce the cost. An example will be described.

In FIG. 2, 1 to 6 are wheels on each axle, 7 to 10 are wheel rotation speed detectors attached to each wheel, 13 to 1j are brake chambers on each axle, 16 is a brake valve, and 17
- 19 are braking force control devices, 20 and 23 are braking force control signal generating devices, and the braking force control signal generating device 23 is configured as shown in FIG. 3, for example.

In FIG. 3, 24 is a differential mechanism operation switch that responds to the operation of the differential mechanism installed between the center axle and the rear axle, 25 and 26 are f-V converters, and 21
is a selection circuit, 28 is a differentiation circuit, 29 is a comparator, 30 is A
The ND circuit 31 and 32 are amplifiers.

Note that the f-V converters 25 and 26 convert the amount of electricity proportional to the wheel rotation speed generated by the wheel rotation speed detectors 9 and 100, and in the embodiment shown in FIG. 3, the number of pulses into a DC voltage corresponding to the wheel rotation speed. The conversion circuit 27 generates a DC voltage corresponding to the sum of the left and right wheel speeds of the center axle, the differentiation circuit 2B detects the wheel deceleration, and the output signal is led to the comparator 29.

The comparator 29 generates a braking force release signal when the wheel deceleration reaches a predetermined set deceleration or more, and
After the current is increased by step 1, the solenoid valve installed inside the braking force control device 18 is operated to gradually reduce the braking force of the center shaft.

When the differential mechanism is not operating, the brake force release signal generated by the comparator 29 is generated by the differential mechanism activation switch 24 and the AND circuit 30.
After the current is amplified by the amplifier 32 via the AND circuit 30, the solenoid valve in the braking force control device 19 is operated to reduce the braking force of the rear axle at the same time as that of the center axle.

Conversely, when the differential mechanism is activated, the braking force release signal generated by the comparator 29 is not guided to the braking force control device 19 due to the functions of the differential mechanism activation switch 24 and the AND circuit 30.

In other words, when the differential mechanism is not operating, the center axle wheel rotation speed and the rear axle wheel rotation speed are the same, so the center axle is controlled by the wheel speed information from the wheel rotation speed detectors 9 and 10 attached to the center axle. By braking the power control device 18 and the rear axle braking force control device 19 simultaneously, locking of the wheels of the center axle and the rear axle is prevented, and only the center axle braking force control device 18 is braked to operate the differential mechanism. Even if the wheels of the rear axle lock due to excessive braking force, the wheels of the center axle can be prevented from locking, thereby ensuring sufficient side force.

In addition, in the above-mentioned embodiment of the present invention, a case was explained in which a wheel rotation speed detector was installed on the center axle.
It is also possible to install a wheel rotation speed detector on the rear axle and to control only the rear axle when the differential mechanism is activated.

As explained above, the present invention makes it possible to omit the wheel rotation speed detector and the braking force control signal generator that were conventionally installed on the rear axle while ensuring the anti-skid device function. This has the advantage of greatly reducing the overall price.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a conventional device, and FIGS. 2 and 3 are block diagrams showing an embodiment of the present invention. In the figure, 1 to 6 are wheels, 7 to 12 are wheel rotation speed detectors,
13 to 15 are brake chambers, 17 to 19 are braking force control devices, 20 to 23 tri braking force control signal generators, 2
4 is a differential mechanism activation switch. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] The vehicle is equipped with 13 axles, including a front axle, a center axle, and a rear axle, and has a function of simultaneously driving the middle and rear axles and controlling the operation of a differential mechanism provided between the center axle and the rear axle. A brake pipe that brakes each axis independently, a wheel rotation speed detection device that detects the rotation speed of the wheel installed on the center or rear axle, and an output from the wheel rotation speed detection device to prevent the wheel from locking. A braking force control signal generating device is provided in the brake piping of the center axle and the rear axle, and the braking force is controlled by the output of the braking force control signal generating device. The first step is to control the A second braking force control device is provided, and when the differential mechanism is not operating, the output signal of the braking force control signal generating device is transmitted to the first braking force control device. At the same time, the output of the braking force control signal generator is input to the second braking force control device, and when the differential mechanism is activated, the output of the braking force control signal generating device is inputted to the braking force control device of one of the center axle or the rear axle where the wheel rotation speed detection device is installed. An anti-skid device for a vehicle, which inputs a signal and deactivates the other braking force control device.