JPS61155961A - Apparatus for detecting rotation - Google Patents

Abstract

PURPOSE:To prevent erroneous operation due to rotary vibration, by latching one of outputs of two sensors, of which the phases are shifted by a predetermined angle, by the other output and counting the latched output. CONSTITUTION:A pair of sensors 11, 12 are arranged in opposed relation to a rotor 100 which was alternately magnetized with N-poles and S-poles in the outer peripheral side thereof and output signals (a), (b) shifted by 90 deg. in a phase when the rotor 10 is rotated. The output signal (a) is sent to an edge detection circuit 14 and a clock signal (c) is generated at the incremental and decremental edges of the signal (a). This signal (c) is connected to the clock terminal CLK of a latch circuit 13 and latches the output signal (b). The output (d) of the latch circuit 13 is sent to a counter 15 and utilized in the detection of the number of rotations or rotary speed of the rotor 10. By this method, because the output signal (b) is not latched at the time of the vibration of the rotor 10, erroneous detection is prevented.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a rotation detection device, and more particularly to a rotation detection device in which a sensor is provided to face a rotating body and the output pulses of the sensor are used to detect the rotational speed or rotational speed of the rotating body.

[Prior art]

For example, when detecting the rotation speed on the output side of an automobile transmission, this rotation is used as a pulse using a Hall element or MR element to extract a detection signal, and this output pulse is used to generate various electronic control devices. becomes possible to operate. Therefore, when controlling the engine or transmission electronically, it is preferable to extract the rotational speed or rotational speed on the output side of the transmission as an electrical signal. In such cases, conventionally a sensor was installed on the outer periphery of the rotor, which rotates in proportion to the rotation speed on the output side of the transmission, and the output of this sensor was waveform-shaped and directly counted by a counter. Ta. The drawback of such conventional rotation detection devices is that when the rotor that is transmitted to the output side of the transmission generates rotational vibration due to photographing the engine, etc., the sensor generates pulses due to the rotational vibration, and the counter In some cases, this pulse was mistakenly counted. Therefore, even when the vehicle is not running, there is a problem in that the rotation is detected as if the rotation speed were present on the output side of the transmission. OBJECTS OF THE INVENTION The present invention has been made in view of these problems, and it is an object of the present invention to provide a rotation detection device that prevents malfunctions due to rotational vibrations.

[Structure of the invention]

The present invention provides an apparatus in which a first sensor is provided to face a rotating body, and the number of rotations or the rotational speed of the rotating body is detected using output pulses of the sensor.
A second sensor that generates a signal whose phase is shifted by a predetermined angle with respect to the output signal of the first sensor, and a latch means, and the output signal of one of the pair of sensors causes the latch to be activated. The rotation detecting device is characterized in that the means is operated to latch the output signal of the other sensor, and the output of the latch means is counted. Correct detection is performed regardless of rotational imaging within the phase difference range. K Embodiment The present invention will be described below with reference to an illustrated embodiment. FIG. 1 shows a rotation detection device according to an embodiment of the present invention, which detects the rotation of a rotating body 10 that rotates in proportion to the rotation speed on the output side of a transmission, for example. ing. The outer circumferential side of this rotary body 10 is magnetized alternately into north and south poles. A pair of sensors 11 and 12 are arranged to face the outer peripheral surface of this rotating body. These sensors 11 and 12 are arranged so that the phase difference of their output signals is shifted by 90''.The output terminal of the first sensor 11 is then connected to the data input terminal of the flip-flop 13. On the other hand, the output side of the second sensor 12 is connected to the edge detection circuit 14, and the output side of the edge detection circuit 14 is connected to the clock terminal of the flip-flop 13. The output signal of
for forming clock signals at the up-edge and down-edge of one of the sensors, for example sensor 12, for example, as shown in FIG. and a second differentiating circuit connected to the output side of the inverter 18 and consisting of a resistor 19 and a capacitor 20, and the output of these two differentiating circuits is taken out via an OR gate 21. This is what I did. According to such a configuration, therefore, clock signals can be obtained at the up edge and down edge of the output of the sensor 12, respectively. Note that the edge detection circuit 14 is not limited to the configuration shown in FIG. 2, but may be a circuit as shown in FIG. 3, for example. This circuit has a resistance of 16.1
9 are each connected to the power supply circuit,
Moreover, the outputs of the two differentiating circuits are taken out via the NAND gate 22. Even in such a circuit, clock signals can be obtained at the up edge and down edge of the output signal of the sensor 12, respectively. Next, the operation of this rotation detection device configured as above will be explained. A pair of sensors 11.1 shown in FIG.
2 generate output waveforms as shown by b and a in FIG. 4, respectively, as detection outputs. The output of the sensor 12 shown in FIG. 4A is converted by the edge detection circuit 14 into a lock signal as shown in FIG. It will be done. Since the output signal of the first sensor 11 is supplied as data to the data input of the flip-flop 13, the output of the sensor 11 is latched at the clock timing shown in FIG. 4C. Therefore, the flip-flop 13 produces an output as shown in FIG. 4d. These output pulses are counted by a counter 15 and detected as the number of rotations or rotational speed on the output side of the transmission. In this way, when the output of the first sensor 11 is latched by the flip-flop 13 by the up edge and down edge of the output signal of the second sensor 12, when the rotating body 10 is rotating in the same direction, the output of the sensor 11 is is inverted for each edge of the output of the sensor 12, so it becomes possible to obtain an output pulse as shown in FIG. 4d from the flip-flop 13, and it becomes possible to perform normal rotation detection. However, when the vehicle is stopped and no rotation is occurring on the output side of the transmission, and the rotating body 10 is making rotational vibrations due to engine vibration, the outer peripheral surface of the rotating body 10 The magnet oscillates relative to the sensor 12 as shown by arrow 25 in FIG. 4a, crossing and returning to the edges of the sensor's 12 output signal. Each time, the flip-flop 13 is latched, but if the magnitude of this rotational vibration is within the range of ±90'' phase difference of the output signal of the sensor 11.12, the output of the first sensor '11 is is not reversed,
The output of flip-flop 13, which is supplied to counter 15, does not change. Therefore, in such a case, counter 1
5 will no longer count incorrectly. Moreover, although the prevention of this malfunction varies depending on the stopping position of the rotating body 10, malfunction can be prevented within a range of at least 90 degrees and at most 180 degrees, so malfunctions due to considerably large rotational vibrations can be prevented. becomes possible.

【Effect of the invention】

As described above, the present invention provides a second sensor that generates a signal whose phase is shifted by a predetermined angle with respect to the output signal of the first sensor, and a latch means, and the output of one of the pair of sensors. The latch means is actuated by the signal to latch the output signal of the other sensor, and the output of the latch means is colored to detect the number of revolutions or the rotation speed. Therefore, according to the present invention, it is possible to provide a rotation detection device that can prevent malfunctions due to rotational vibration within the range of the phase difference of signals and can more accurately detect the number of rotations or rotational speed. It becomes like this.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a rotation detection device according to an embodiment of the present invention, FIG. 2 is a circuit diagram of an edge detection circuit of this rotation detection device, and FIG. 3 is a circuit diagram of an edge detection circuit according to a modified example. The circuit diagram and FIG. 4 are waveform diagrams showing the operation of the rotation detection device. In the symbols used in the drawings, 10...Rotating body 11...First sensor 12...Second sensor 13...Flip-flop 14...Edge detection circuit 15...Counter.

Claims (1)

[Claims] In the apparatus, a first sensor is provided to face the rotating body, and the number of rotations or the rotational speed of the rotating body is detected using an output pulse of the sensor.
a second sensor that generates a signal that is out of phase by a predetermined angle with respect to the output signal of the sensor, and a latch means,
The latch means is operated by the output signal of one of the pair of sensors to latch the output signal of the other sensor, and the output of the latch means is counted. Rotation detection device.