JPS6358167A - Trouble detector for rotation sensor - Google Patents

Abstract

PURPOSE:To certainly detect the trouble of a rotation sensor without erroneous detection, by detecting the disturbance of the output pulse of a tone wheel as a square wave and judging an abnormal state on the basis of the change quantities before and after the pulse width thereof. CONSTITUTION:In a rotation sensor, the pulse formed by the profile part of the tone wheel 2 connected to a rotary shaft 1 is counted by a detector 4 and subjected to frequency division in a certain ratio by a frequency dividing part 9 and a frequency dividing wave pulse width is measured by a pulse width measuring part 10. When there is an abnormal state such that the change quantities of the respective pulse widths of adjacent mutual frequency dividing waves become a predetermined value or more and an abnormal state in steady rotation at a definite speed or more reaches the definite number of times, a predetermined output order such as an alarm is applied to an output part 12 from a detection control part 11. For example, when the teeth of the profile part 3 are broken, the pulse corresponding to the broken part is not generated and the pulse width of a frequency dividing wave long as compared with that of the frequency dividing wave of a normal pulse is detected by the pulse width measuring part 10 and, when said pulse width becomes a predetermined value or more, an order is outputted to the output part 12 from the detection control part 11.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a failure detection device for a rotation sensor used for detecting the rotational speed of a wheel shaft of an automobile, etc. By detecting this, it is possible to detect malfunctions such as missing teeth in the tone wheel.

(Conventional technology and problems) Conventionally, failure detection in this type of rotation sensor relied on the operator's touch, which made it difficult to detect a failure if the operator was inexperienced. .

(Means for Solving the Problem) The present invention proposes a simple detection sensor having a configuration devised to ensure failure detection. A rotation sensor that counts pulses generated by the irregularly shaped portion 3 of the wheel 2, and a frequency dividing portion 9 that divides the frequency of the pulses at a certain ratio.
and measures the i9 pulse width of the frequency-divided wave.Grus width measurement unit 1
o, and when there is an abnormal state in which the amount of change in the Noculus width of each adjacent mutual frequency-divided wave is equal to or greater than a predetermined value, and when the above-mentioned abnormal state reaches a predetermined number of times during steady rotation at a constant speed or higher, the output section 12 This is a rotation sensor failure detection device having a detection control section 11 configured to give an output command such as a predetermined alarm to the rotation sensor.

(Function) For example, in a tone wheel 2 that is used as the irregularly shaped part 3 and has a missing tooth, the missing tooth corresponds to the part/
-, O pulse is not generated and the frequency-divided wave is detected by the pulse width measurement unit 10 as having a longer pulse width than the frequency-divided wave of other adjacent normal pulses, The detection control unit 11 detects an abnormal state in which the amount of change in pulse width of each of the abnormal frequency-divided wave and the normal frequency-divided wave exceeds a predetermined value.

Since this abnormal state reaches a certain number of times, a command is output from the detection control section 11 to the output section 12, and the output section 12 outputs a predetermined alarm or the like.

(Example) Next, an embodiment of the present invention will be described based on the drawings.

As illustrated in the block diagram in FIG. 1, the movement of a large number of teeth formed on a tone wheel 2 connected to a rotating shaft 1 such as a wheel axle, or a deformed part 3 such as a small hole (not shown) is controlled. It is detected by an optical type or magnetic type detector 4, and the /- detected by this is shown in FIG.
, Q Lus A is amplified by an amplifier 5, calculated as a rotational speed by a speed calculation unit 6, and the calculated rotational speed is used in a system control unit 7, which is provided to perform something such as traction control, for example. There is.

For fault detection, the Nogle Ai shaping circuit 8 shapes the square wave B' as shown in FIG. The frequency-divided wave C illustrated in FIG.
Measured by.

Pulse widths T1 and T of adjacent ones of the measured frequency-divided wave C
2. T2 and T3. ..., that is, T, -T2. T2-
The detection control unit 11 calculates the amount of change ΔT by setting T3p as the amount of change ΔT.
T2...), this is counted as an abnormal state, and when the count number n of this abnormal state reaches a certain number N (for example, 3 times), the detection control section 11 outputs the output section 12. The alarm unit 13 is configured to output an alarm command to the alarm unit 13, as an example, and instruct the system control unit 7 to deactivate.

When the rotating shaft 1 is, for example, a wheel shaft of a car, the above failure detection operation is performed when the rotational speed VM ih is equal to or higher than a constant speed V1 (for example, 30 km/h') and is a steady rotation with no brake applied. The rotational speed vM is, for example, the highest rotational speed of the four wheel axles.

The above control operation is shown in the flowchart in Fig. 4, and in the example shown as a time chart in Figs. Since the pulse widths T1 to T6 and Tlf: T2 and T3 are such that ΔT3 (=T3-T2)≦K (=10,000 T2), abnormal states are not counted.

Even during acceleration operation or chinastone, the amount of change in pulse width Δ
Since T satisfies ΔT≦, an abnormal state is not currented.

As an example of a failure, an example of failure detection when one tooth of the tone wheel 2 is missing is shown in Figures 3(a) to (a).
As shown in c), the pulse X output from the detector 4 is
A flat portion f1 corresponding to one cycle appears, and a flat portion f2 occurs in the shaped square wave Y.

This causes the frequency division wave 2 to be no<? The pulse width is smaller than the pulse width T1 when detecting a part without tooth chipping, compared to the pulse width T1 when detecting a part with tooth chipping.
T1 and Nasi, ΔT, (-T, -T1)≧K(-100T1
), the abnormal state is counted.

In the case of such a tooth chipping, the abnormal state is counted repeatedly with the number of times. For example, when the rotating shaft rotates several times, the number of counts n reaches a certain number N, and an alarm is output to the alarm unit 13. will be ordered.

As an example of a failure, for example, in the case of a temporary contact failure between the connector between the detector 4 and the amplifier 5, the count of abnormal conditions is:
Since the force is applied only once or twice, no commands such as alarms are output.

When the brake is not applied and the brake is not applied and the vehicle is in an accelerating state or a sluggish state, the adjacent radius width T1. T2. The difference between... is small, and as shown in Figure 2 (c) above, ΔT2゜ΔT
Since 6≦, it is not determined to be an abnormal state.

Judgment as to whether the brake is in the state is made by inputting, for example, the output of a brake switch that detects the operation of the brake pedal into the detection control unit 11. Also, if the brake is applied in the middle of counting an abnormal state, , the count of the detection control unit 11 is configured to be cleared.

For example, the pulse width measurement unit 10 opens a dart of a counter at the rising edge of the frequency-divided wave C, closes the dart at the falling edge of the frequency-divided wave C, and counts the clock signal input during this period. This is to measure the period T1 of .

Pulse width measurement section 10, rotation speed calculation section 6, detection control section 1
1 can be configured by a microcomputer 13, for example.

(Effects of the Invention) The rotation sensor failure detection device according to the present invention is configured as described above, and detects disturbances in the output and pulse of the tone wheel 2 as a square wave.・
An abnormal state is detected based on the amount of change before and after the pulse width, and when this abnormal state reaches a certain number of times, it is determined as a failure. Defects are eliminated and failures that require repair can be reliably detected, and since acceleration of the rotating shaft 1 and fluctuations in rotational speed due to the china stone are not detected, there is no false detection of failures in the rotation sensor. It can be reliably detected.

[Brief explanation of drawings]

The figures show an embodiment of the present invention, in which Fig. 1 is a block diagram of the control circuit, Figs. (B) and (C) are abnormal conditions 1...Rotating shaft, 2...Tone wheel, 3...
- Unusual part, 9... Frequency division part, 10... Pulse width measurement part, 11... Detection control part

Claims (1)

[Claims] A rotation sensor that counts pulses generated by an irregularly shaped part of a tone wheel coupled to a rotating shaft, comprising: a frequency dividing section that divides the frequency of the pulse at a certain ratio; There is an abnormal state in which the pulse width measurement unit that measures the pulse width and the amount of change in the pulse width of the adjacent front and rear divided waves exceed a predetermined value, and the above abnormal state is constant during steady rotation at a constant speed or higher. 1. A failure detection device for a rotation sensor, comprising: a detection control section configured to give an output command such as a predetermined alarm to an output section when a specified number of times is reached.