JPS63287652A - Anti-lock device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an anti-lock device for detecting the locked state of the wheels of an automobile and efficiently applying braking force.

[Conventional technology]

The anti-lock device has a configuration roughly as shown in FIG.

First, the AC voltage supplied from the wheel speed sensor S is converted into pulses by the interface circuit 22, counted by the pulse processing circuit 23, and inputted to the calculation and lock state detection circuit 24 as a wheel speed signal. This circuit 2
In step 4, the estimated vehicle speed, deceleration, or acceleration is calculated based on the wheel speed signal, and by comparison with various threshold values, if the wheels tend to lock, a brake pressure reduction command is issued; Further, when the lock is in a tendency to recover, a pressure increase command is issued.Furthermore, depending on certain conditions, a brake pressure maintenance command may be issued even during a pressure reduction or pressure increase command.

Now, when a pressure reduction command is issued from the circuit 24, the solenoid drive circuit 25 excites the solenoid SQL+ and the solenoid 5OLx. Then, pressure control valves V and VO both move to the left in the figure, and control valve V.

shuts off the hydraulic circuit from the hydraulic pressure generation source consisting of the master cylinder 26 and the pump P, and the control valve V2 connects the hydraulic circuit from the wheel cylinder 27 to the reservoir 28. Therefore, the brake pressure is reduced.

When the pressurization command is issued, the solenoid drive circuit 2
5, when solenoid SQL+ and 5OLt are demagnetized,
Pressure control valves v1 and (2) both move to the positions shown in the figure, allowing the hydraulic pressure generation source and the wheel cylinder 27 to communicate with each other.

Also, when a pressure hold command is issued, solenoid S
When the solenoid QL is energized and the solenoid sot, z is deenergized, the control valve v1 moves to the left in the figure, and the control valve V8 remains as it is in the figure, so the wheel cylinder 27 becomes the hydraulic pressure generation source. The pressure is cut off from the wheel cylinder 2.
7 is trapped in the circuit.

Brake pressure is therefore kept constant.

In this way, in the anti-lock device, a pressurization command is issued when a lock recovery tendency appears, but in order to detect a lock recovery tendency, for example, when the acceleration of the wheel exceeds a certain threshold, A method has been used in which the slip rate (estimated vehicle speed - wheel speed or estimated vehicle speed - slip rate evaluation value - wheel speed) becomes below a certain threshold.

(Problems with the conventional technology) However, if the occurrence of a lock recovery tendency is determined based only on acceleration, for example, if there are irregularities or obstacles on the road, and the wheel speed changes slightly and rapidly, There is a risk that the lock may be determined to have recovered even though there is no tendency to recover, and a pressurization command may be issued regardless of the temporary change.

Therefore, if the threshold value of acceleration is made sufficiently large, there is a problem in that the lock recovery tendency cannot be detected early and undesired pressure reduction occurs.

On the other hand, if the judgment is made based on a constant slip ratio, there is a problem in that excessive depressurization tends to occur until the slip ratio at which the locking tendency is initially detected is reached.

The purpose of this invention is to solve the above problem and set the threshold value to
It is an object of the present invention to provide an anti-lock device that can be set sufficiently large to perform appropriate early detection of lock recovery symptoms, and therefore has fewer false judgments.

[Means for achieving the purpose]

In order to achieve the above object, the present invention detects the occurrence of a lock recovery tendency only when the slip rate exceeds a slip recovery threshold after detecting the peak value of wheel deceleration. I made it.

[Effect]

By detecting the peak value of wheel deceleration, the first signs of wheel speed recovery can be seen;
A sufficiently large threshold can be set to detect a lock recovery tendency, and therefore a lock recovery tendency can be detected early.

〔Example〕

As shown in FIGS. 1 and 2, a wheel speed detection means 1 including a wheel speed sensor, an interface circuit, and a pulse processing circuit supplies a pulse signal proportional to the rotational speed of the wheel, and a wheel speed calculation circuit 2 and the wheel speed signal V. Output. The estimated vehicle speed calculation circuit 3 receives the signal V1 and calculates the estimated vehicle speed (2). On the other hand, the slip rate evaluation signal calculation circuit 4 calculates the slip rate evaluation signal S based on the wheel speed signal V@ and the vehicle speed signal ■9, and the circuit 5 calculates the slip rate evaluation signal S based on the wheel speed signal V@ and the vehicle speed signal ■9. Svν
, S, the slip rate signal λ (−Vv −3−Vw
) and output it. Note that although the slip rate evaluation signal S is used for subtraction here, this signal S may not be used.

The above-mentioned signals λ are respectively supplied to evaluation circuits 6.7, which include a slip start threshold λ1 and a slip recovery threshold λ2.
Evaluate the results with on/off logic signals 0□,
Output with 03.

The wheel speed signal V. is supplied to the differentiation circuit 8, and the deceleration of the wheel is calculated. Deceleration signal as calculation result*
Yes, it is supplied to the deceleration evaluation circuit 9, and the deceleration threshold -
b and the result is output as a logic signal o1. On the other hand, the deceleration signal *0 is the deceleration peak detection circuit 11
When a peak is detected, it outputs signal 04,
This causes flip-flop 12 to become cent. Note that the flip-flop 12 is reset by a signal 0°, which will be described later.

Now, when the brake is applied and the wheel speed signal VW begins to decrease, the circuit 3 generates a predetermined estimated vehicle speed signal . The circuit 4 receives the signals VV and - and calculates the slip evaluation signal S, and the circuit 5 calculates the slip rate signal λ
Calculate. When this signal λ exceeds the threshold λ1, the circuit 6 turns on the signal Ox. Additionally, a wheel speed signal V. The deceleration signal Ω1, which is the differential value of turns on. Therefore, the output signal 03 of the AND gate 14 is turned on. On the other hand, since the peak of deceleration has not yet appeared, signal 04 is off, so signal 0. remains off. Therefore, the output signal of the AND gate 16 is 0. is turned on, but when the peak of deceleration is detected, the peak value detection signal 04 is turned on, the flip-flop 12 is activated, and the signal 0. is turned on, and the output signal O1 of the AND gate 16 is turned off.

The output signal of the flip-flop 12 is input to the AND gate 15, and the output of the evaluation circuit 7 is input to the AND gate 1.
Connected to the negative end of 5. Right now, the signal is 0. is on and the slip rate signal λ is not below the slip recovery threshold λ8, so the output signal of the evaluation circuit 7 is 0. is turned off.

4 and the output signal O of AND gate 15? Turns on.

The output signals of AND gates 16 and 15 are 0. and 0° are input to the OR gate 17, so the signal 0□ is on and the signal 0? is off, the output signal of the OR gate 17, that is, the decompression signal 0. is on, and the signal 0. After is turned off,
Since the signal O, is turned on, the depressurization signal O9 is also
It's on. Then signal 0. turns off when the output signal O3 of the evaluation circuit 7 turns on and the signal 0 turns off, that is, when the value of the slip rate signal λ falls below the slip recovery threshold λ2. It is.

After the peak value of the deceleration signal YW is detected by the circuit 11 and the flip-flop 12 is activated, when the slip rate λ becomes lower than the threshold value λ2 as described above, the signal O3 is activated.
and 0. are both turned on, and therefore the output signal of AND gate 18 is 0. . That is, the pressurization signal is turned on. After this signal o1° is turned on, the signals 01 and 0!
When both are turned on, the flip-flop 12 is reset and the pressurization signal 010 is turned off.

In addition, the above-mentioned pressure reduction signal 0. and pressurization signal 0. . is supplied to the solenoid drive circuit 25 to drive the solenoid of the pressure control valve with the signal 0. and 0. . It is designed to be driven according to the following.

Note that the above circuit can of course be configured as hardware, but the same function may be provided in software stored in a microcomputer.

〔effect〕

According to the present invention, as described above, after detecting the peak value of wheel deceleration, it is determined whether the slip rate recovery threshold has been exceeded. can be set large enough for early detection, thus eliminating malfunctions caused by road surface conditions and preventing over-depressurization, which is common when judgments are made only based on acceleration or a certain slip ratio threshold. effective.

[Brief explanation of the drawing]

FIG. 1 is a schematic circuit diagram showing an embodiment of the anti-lock device of the present invention, Part 2 is an operating diagram thereof, and FIG. 3 is a diagram showing the concept of a conventional anti-lock device. 1... Wheel speed detection means, 2... Wheel speed calculation circuit, 3... Estimated vehicle body speed calculation circuit,
5...Slip rate calculation circuit, 6.7...
- Slip rate evaluation circuit, 8...Wheel deceleration calculation circuit, 9...Deceleration evaluation circuit, 11...
・Deceleration peak detection circuit, 12...Flip-flop, 14.15.16...AND gate,
17...OR gate, 24...Calculation and lock state detection circuit.

Claims (1)

[Claims] In response to the wheel speed signal from the wheel speed detection means, the calculation and lock state detection means detects a tendency of the wheels to lock, issues a pressure reduction command, and detects a tendency for lock recovery to issue a pressure increase command. In the lock device, the calculation and lock state detection means calculates the wheel deceleration, which is a differential value of the wheel speed, and after detecting its peak value, the slip rate, which is the difference between the estimated vehicle speed and the wheel speed, is determined by the slip recovery. An anti-lock device characterized by comprising means for detecting that a lock recovery tendency occurs when a threshold value is exceeded.