JPS5828526B2 - rotation detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rotational position detection device for detecting the rotational position of a crankshaft, etc. of an engine in an automobile, which detects the rotational position without delay regardless of the rotational speed of the crankshaft, etc. It is.

Conventionally, devices for detecting the rotation of, for example, the crankshaft of a car engine, have been designed to rotate by winding a coil around a magnetic material and facing the rotating body, and inducing an alternating electromotive force in the coil due to changes in magnetic flux caused by the unevenness of the rotating body. There is something that detects body rotation.

However, in this type of device, the alternating electromotive force induced in the coil is affected by changes in the magnetic flux applied to it, that is, the rotational speed of the rotating body, and when the rotational speed of the rotating body is low, the alternating electromotive force induced in the coil is affected by the rotational speed of the rotating body. This has the disadvantage that it hardly occurs and it is impossible to detect the rotation of the rotating body.

The present invention solves the above-mentioned drawbacks, and includes a plate attached to a rotating body and a plate arranged opposite to the plate and fixed to a housing, and in which a plate is arranged at regular intervals on opposing surfaces of both plates. LC refers to cases in which electrodes are arranged in the circumferential direction, and the electrodes on one plate and the electrodes on the other plate face or do not face each other due to rotation.
It is an object of the present invention to provide a rotation detection device that can satisfactorily detect the rotation of the rotating body by detecting the resonance waveform of a resonance circuit.

The present invention will be described below with reference to embodiments shown in the drawings.

FIG. 1 is a sectional view showing the overall configuration of the device of the present invention,
100 is a housing fixed to the outside of the bearing 110, 120 is a shaft fixed to the inside of the bearing 110, and 130 is a printed board housing the detection circuit section 101, which is fixed to the housing 100.

Further, 140 is a first plate made of a printed board fixed to the housing 100 with screws 170, 150 is a second plate made of a printed board fixed to the rotating body 160 with screws 180, and the rotating body 160 is fixed to the rotating body 160 with screws 190. Since it is fixed to the shaft 120 by
The rotation of the shaft 120 causes the second plate 150 to
rotates to face the first plate 140.

Further, FIGS. 2a and 2t) are plan views showing the opposing surfaces 140a and 150a of the first plate 140 and the second plate 150, and as shown in FIG. A first electrode 141 in the shape of a shape is arranged by printing, and a signal from the detection circuit section 101 is connected to a connection section 142 by a lead wire 102.
is transmitted through.

Further, as shown in the figure, a second electrode 151 is arranged by printing on the second plate 150 in correspondence with the electrode 141 of the first plate 140.
51 is connected to the rotating body 1 made of a conductor via a connecting part 152.
60 and shaft 120).

Next, FIG. 3 shows details of the detection circuit section 101 which includes a capacitor 332 as one element, which is composed of the first electrode 141 of the first plate 140 and the second electrode 151 of the second plate 150. Shows the electrical wiring diagram.

In FIG. 3, 300 is a storage battery, 30L 302 is a power supply terminal and a ground terminal, and 303 is an output terminal that outputs a signal of "1 per or 0" in response to the rotation of the second plate 150.

310 is an oscillation circuit, and inverter gates 311 . Crystal oscillator 315, resistors 313, 314, capacitor 316,
317 and an inverter gate 312 for inversion amplification, and an oscillation signal of a constant frequency appears on the signal line 10.

320 is a frequency dividing circuit, which is frequency-divided by a binary counter 321 to a frequency at which the resonant output of a resonant circuit 330 (described later) is maximum (hereinafter referred to as the fundamental frequency), and inverted and amplified by inverter gates 322, 323, and 324. After that, the 3 LC signals sent to the LC resonant circuit 330
The resonant circuit 330 includes a coil 331 and the capacitor 3 described above.
32, and the second plate 1
The capacitance of the capacitor 332 changes according to the rotation of the capacitor 50, and an output having a phase different from the fundamental frequency (hereinafter referred to as a resonant waveform) is obtained.

340 is a limiter circuit, which is composed of a coupling capacitor 341 and diodes 342 and 343, and clips the resonant waveform obtained by the LC resonance circuit 330 with the upper limit level being the power supply voltage level and the lower limit level being the ground potential. The signal is then sent to an inverter gate 351 for inversion amplification.

350 is a phase detection circuit, D type flip-flop 3
A waveform obtained by inverting and amplifying the fundamental frequency by an inverter gate 353 is sent to the data terminals 54 and 355, and a clock terminal of the D-type flip-flop 354 is sent to the inverter gate 351 for inverting amplification.
The obtained waveform is further passed through an inverter gate 352 for inversion amplification, and also to a D type flip-flop 3.
The waveforms obtained through the aforementioned inverter gate 351 for inverting amplification are respectively input to the clock terminals of 55, and the output signals of the D type flip-flops 354 and 355 are input to the NAND gates 356, 357, 358, 3.
A logical operation is further performed in step 59 to turn on or off the transistor 363 of the output circuit 360, thereby appearing at the output terminal 303 as a 0" or '1" signal.

In the output circuit 360, 361 and 362 are resistors.

Next, the operation of the above configuration will be explained.

First, in FIG. 3, the operation will be described in the case where the AC signal Emsin (ωt+θ) is applied to the LC resonant circuit 330.

If the inductance of the coil 331 is the inductance, the resistance component is R, and the capacitance of the capacitor 332 is C, the current 18 flowing through the coil 331 is, and the voltage IEI appearing at the connection between the coil 331 and the capacitor 332 is, and the voltage IEI is the capacitor. Due to the capacitance C of 332, the signal becomes a signal whose phase changes with respect to the AC signal Emsin (wt+θ).

As shown in FIG. 4C, the resonant frequency of the LC resonant circuit 330 when the second electrode 151 of the second plate 150 corresponds only half to the first electrode 141 of the first plate 140 is as described above. It is assumed that the fundamental frequency of

Therefore, as shown in figure a, when the second electrode 151 is in a position completely corresponding to the first electrode 141, the first and second
A capacitor 33 composed of electrodes 141 and 151 of
The capacitance of 2 is maximum, and as shown in the figure,
When the electrode 151 hardly corresponds to the electrode 141,
The capacitance of the aforementioned capacitor 332 is minimal.

Therefore, in the case of Figure 4a where the capacitance is maximum,
The phase difference with the fundamental frequency is maximum, and as shown in Figure 5, waveform 4 is delayed by approximately 180 degrees from the fundamental frequency 30.
0, and in the case of FIG. 4 where the capacitance is minimum, a resonant waveform 50 having substantially the same phase as the fundamental frequency 30 appears as shown in FIG. 5C.

Moreover, the waveform in FIG. 5d is the resonance waveform 60 in the case of FIG. 4C.
It is.

As described above, the electrode 1 of the second plate 150
51, the output terminal of the LC resonant circuit 330 shown in FIG. correspond) or in opposite phase (when the first
When the electrode 141 and the second electrode 151 do not correspond), the waveforms appear sequentially, so the D-type flip-flops 354 and 355 combine the signal whose fundamental frequency is inverted and amplified by the inverter gate 353 with the LC resonance circuit 330.
By logically calculating the phase difference with the output signal, the output terminal 303 outputs a signal of -1... or "O".

Also, the NAND gates 356, 357°358 in FIG.
．． The flip-flop composed of 359 has an output terminal 30
This is to prevent chattering when the output signal appearing at 3 changes from "1." to "On" or from "etott" to "lv.".

In the embodiment described above, the second electrode 151 is grounded, but a signal between the second electrode 151 on the rotating side and the detection circuit section 101 on the stationary side is transmitted by a signal transmission means such as a slip ring or a brush. It is also possible to transmit the information.

As described above, in the device of the present invention, electrodes are arranged circumferentially at the same intervals on the second plate attached to the rotating body and the first plate attached to the stationary side, respectively. LC that has a capacitor as one element
Since rotation is detected by the phase shift of the resonant waveform of the resonant circuit, there is an excellent effect that rotation can be detected satisfactorily even at low speed rotation by changing the capacitance of the capacitor.

In addition, by grounding the second electrode placed on the second plate attached to the rotating body, there is no need to run a connecting wire from the rotating first plate, and for example, the rotating body can be grounded. It is possible to directly fix the second plate to the rotating body even if there is a rotary body.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view showing the overall configuration of an embodiment of the device of the present invention, FIGS. 2 a and b are front views showing the first and second plates of the device shown in FIG. 1, and FIG. 3 Figure 1 is a detailed electrical connection diagram of the detection circuit in the illustrated device, Figure 4a
, b, and c are electrical circuit diagrams in various states of the electrodes to explain the operation of the device shown in FIG. 1, and FIG. 5 is a diagram of voltage signal waveforms at various points to provide an explanation of the operation of the device shown in FIG. 1. 101... detection circuit, 140... first plate,
141... First electrode, 150... Second plate, 151... Second electrode, 160... Rotating body, 31
0°320...Oscillation circuit and frequency dividing circuit constituting a periodic signal supply circuit, 330...LC resonant circuit, 331...
Coil, 332... Capacitor, 350... Phase detection circuit.

Claims (1)

[Scope of Claims] 1. A first plate having first electrodes arranged in the circumferential direction at equal intervals, and a first plate having first electrodes arranged in the circumferential direction at the same intervals at a position facing the fourth electrode. a second plate having two electrodes and rotating together with the rotating body; and a capacitor and coil formed by the first and second electrodes. Rotation characterized by comprising a periodic signal supply circuit that supplies a signal, and a phase detection circuit that detects rotation by detecting the phase state of the output signal of the periodic signal supply circuit and the output signal of the LC resonance circuit. Detection device. 2. The rotation detection device according to claim 1, wherein the second electrode is grounded.