JPS5850899B2 - Ijiyou Kenshiyutsu Kairo Oyuusuru Antiskitsudo Seigiyosouchi - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an anti-skid control device for an automobile, and particularly to an abnormality detection circuit thereof.

2. Description of the Related Art Conventionally, anti-skid control devices have been known in automobiles that use a vehicle speed signal and a wheel speed signal to detect a slip state of a wheel during braking and control a braking device.

An example is shown in FIG. For convenience of explanation, the output signal frequencies of wheel speed detector 1 and vehicle speed detector 2 are respectively fω
, fd, and both are equal during normal driving.

Furthermore, if the number of stages of the digital counters 31 and 32 is 3 and 4 stages, respectively, the counter 31 is
An output is output from the side, which resets the flip-flop 5 and at the same time clears both counters via the OR circuit 4.

When the flip-flop 5 is in the reset state, the braking device 6 is operated by the braking signal B.

Next, the wheels slip during braking, and fω is approximately 1 of fd.
/2 or more, the counter 32 outputs an output and the flip-flop 5 is set.

When the flip-flop 5 is in the set state, the brake device 6 does not operate regardless of the presence or absence of the brake signal B, and loosens the brake to prevent the wheels from slipping.

In the above anti-skid control device, the vehicle speed detector 2 (
Or, if an abnormality occurs in the wheel speed detector 1) and fd abnormally decreases (or fω increases abnormally), the flip-flop 5 will maintain the reset state even when the wheel slips, and the anti-skid device It will not work as such.

Conventionally, in order to detect this abnormality, a separate circuit similar to the circuit shown in FIG. 1 has been installed, which tends to increase the circuit scale.

An object of the present invention is to simplify the circuit by making the anti-skid circuit and the abnormality detection circuit common.

Hereinafter, the present invention will be explained in detail with reference to Examples.

The circuit shown in FIG. 2 is a circuit in which a timer circuit 7 for abnormality detection is added to the circuit shown in FIG. 1.

If there is no abnormality in the device shown in FIG.
"), the timer is reset, and when the output signal 8 is "o" (or "1"), the timer continues to operate, and the timer continues to operate for a certain period of time (
It functions to output an abnormality detector signal after the abnormality judgment time).

As described in the explanation of FIG. 1, it operates as an anti-skid control device.

During non-braking, a rectangular wave signal with a frequency corresponding to fd is output to the second stage output 8 of the counter 32, so the timer circuit 7 is reset and no abnormal signal is output.

Next, if the fd drops abnormally due to a failure during non-braking, or fd
ω has abnormally increased to about 1/2 of fd7111'5fω
If the value is below, both counters are reset by the output of the counter 31 before the reset signal 8 is output, and therefore the reset signal 8 is not output.

If such a state continues for longer than the abnormality determination time set in the timer, the timer circuit 7 will output an abnormality detection signal 9.

The circuit shown in FIG. 2 above is an example of implementation, and the counter 31
The number of stages of the counter 32, from which part of the counter 32 the reset signal 8 is taken, etc. can be freely selected according to design specifications.

[Brief explanation of drawings]

FIG. 1 is a conventional anti-skid control circuit diagram, and FIG. 2 is an anti-skid control circuit diagram to which an abnormality detection circuit of the present invention is added. 1: Wheel speed detector, 2: Vehicle speed detector, 31°32: Binary counter, 4: OR circuit, 5: Flip-flop, 6
: Braking device, 7: Timer circuit.

Claims (1)

[Claims] 1. Counter A receives a signal with a frequency proportional to the vehicle speed, and counter B receives a signal with a frequency proportional to the wheel speed. Set by the output of counter A and reset by the output of counter B. A flip-flop, a circuit for clearing both counters by an output signal from either one of the counters, and an output signal of the intermediate stage of the counter A for use as a detection signal for an abnormal decrease in vehicle speed or an abnormal increase in wheel speed. An anti-skid control device comprising an abnormality detection circuit that detects.