JPH07286807A - Magnetic rotation detector - Google Patents

Abstract

PURPOSE:To provide a highly reliable magnetic rotation detector which can accurately detect the rotating direction and rotational angle of a shaft to be detected even when the 50% duty ratio of the output signal of a magneto-electric converter element declines. CONSTITUTION:The magnetic rotation detector is provided with a rotor 13 for CW and another rotor 14 for CCW put on a shaft 11 to be detected for rotation in parallel with each other, one-way clutch bearing 12 which makes the rotors 13 and 14 to oppositely rotate in one directions only, a galvanomagnetic device 15 which is counterposed to the respective rotors 13 and 14, and a processing circuit 21 connected to the element 15.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic rotation detecting device using a magnetoelectric conversion element in home electric appliances, electric components and the like.

[0002]

2. Description of the Related Art Conventionally, as a technique in such a field,
For example, there were the following. FIG. 5 is a block diagram of a conventional magnetic rotation detecting device, and FIG. 6 is an output waveform diagram of the magnetic rotation detecting device.

As shown in FIG. 5, the multi-pole magnet rotor 2 attached to the rotation detection shaft 1 is magnetized with the required number of poles, and the magnetic force changes due to the rotation of the multi-pole magnet rotor 2. For example, Hall element or MR
A magnetic-electric conversion element 3 such as an element converts the signal into an electric signal, a waveform shaping circuit 4 performs waveform shaping, and outputs the signal to a processing circuit such as a digital IC up / down counter 5.

When the change in magnetic force of the multi-pole magnet rotor 2 is converted into an electric signal, the output of the magnetoelectric conversion element 3 is usually a sine wave. When detecting the rotation angle and the rotation direction, the outputs of the two magnetoelectric conversion elements 3 are detected. Is shifted by 1/4 cycle, 2
It is common to arrange two magnetoelectric conversion elements 3 as shown in FIG.
Is the output waveform. That is, when the multipole magnet rotor 2 rotates in the CW (clockwise) direction, the magnetoelectric conversion elements A and B arranged so as to be displaced from each other by 1/4 cycle,
The pulse of the output V _A2 of the magnetoelectric conversion element A rises first,
The output of the magnetoelectric conversion element B, V _B2 , rises with a delay of ¼ cycle. During CCW (counterclockwise) rotation, the output V _B2 of the magnetoelectric conversion element B rises first, and the output V _A2 of the magnetoelectric conversion element A rises with a delay of ¼ cycle.

Therefore, the direction of rotation of the rotated shaft can be determined by the rising order of the outputs of the magnetoelectric conversion elements A and B. For example, by inputting / outputting the output to the digital IC up / down counter 5, for example, the up / down clock terminal of the 74193, the up / down counter 5 is operated when the rotation detection shaft 1 rotates in the CW direction.
Performs a countdown operation, and performs a countup operation during rotation in the CCW direction, and the integrated value of the up / down counter 5 can calculate the rotation angle of the rotation detection shaft 1.

[0006]

However, in the above-mentioned conventional device, a duty ratio of 50% is required to detect the rotation direction and the rotation angle due to the phase relationship between the two waveforms, and the duty ratio of 50% is required. In order to ensure this, it is necessary to match the threshold value of the waveform shaping circuit with the output amplitude center voltage of each magnetoelectric conversion element.

FIG. 7 is a diagram showing each state of the output waveform of the magnetoelectric conversion element, the threshold value of the waveform shaping circuit, and the output waveform of the magnetic rotation detecting device. FIG.
/ 4 cycle-shifted waveform diagram in the normal state, FIG. 7B is a waveform diagram in which the output potential of the magnetoelectric conversion element is low due to variations in the magnetoelectric conversion elements A and B and aging, and FIG. 7C is in the CW direction, CCW
It is a direction repeated minute rotation waveform chart.

That is, FIG. 7A shows a waveform in which the output amplitude center voltage of the magnetoelectric conversion element and the threshold value of the waveform shaping circuit are in a normal state. However, if the threshold value of the waveform shaping circuit is fixed, as shown in FIG. 7B, the output amplitude center voltage and the threshold value may be significantly deviated due to variations in the magnetoelectric conversion element and aging. As shown in FIG. 7C, there is a problem that such a state becomes indistinguishable from the output waveform generated when the minute rotations in the CW direction and the CCW direction are repeated.

Further, in order to eliminate these and obtain stable performance, it is necessary to add a special circuit such as automatic calculation of the amplitude center voltage, which causes a significant cost increase. . In order to eliminate the above-mentioned problems, the present invention is a highly reliable magnetic rotation detecting device capable of accurately detecting the rotation direction and the rotation angle even if the 50% duty of the magnetoelectric conversion element output signal is broken. The purpose is to provide.

[0010]

In order to achieve the above object, the present invention provides, in a magnetic rotation detection device, two multipole magnet rotors arranged in parallel on a rotation detection shaft, and the two multipoles. A clutch mechanism in which the magnet rotor rotates only in one direction opposite to each other, a magnetoelectric conversion element facing each of the two multipole magnet rotors, and a processing circuit connected to the magnetoelectric conversion element are provided. is there.

[0011]

According to the present invention, as described above, two multi-pole magnet rotors that rotate only in one direction opposite to each other are arranged side by side, and are attached to the same rotation detection shaft. Independently, the magnetoelectric conversion elements are installed facing each other. Therefore, since the output can be extracted for each rotation direction, the rotation direction can be determined and the rotation angle can be detected regardless of the duty.

[0012]

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a block diagram of a magnetic rotation detecting device showing an embodiment of the present invention. Here, the same number of magnetisations is appropriately applied to the multipole magnet rotor set. As shown in FIG. 1, a multi-pole magnet rotor set 10 has a one-way clutch bearing 12 (for example, NTN HF one-way clutch bearing) as a clutch mechanism fitted in the center thereof, and the CW rotor 13 is The rotation detection shaft 11 rotates only when it rotates in the CW direction, and idles when it rotates in the CCW direction.
On the contrary, in the CCW rotor 14, the rotation detection shaft 11 is C
It rotates only when rotating in the CW direction, and idles when rotating in the CW direction.

The multi-pole magnet rotor set 10 includes
Magnetoelectric conversion elements 15 (A, B) are installed facing each other, and the outputs thereof are connected to the processing circuit 21.
That is, the waveform shaping circuit 22 and the falling differentiation circuit 2
3. Connected to digital IC up / down counter 24. Also, the output V _A1 of the waveform shaping circuit 22,
V _B1 is connected to the falling differentiation circuit 23, and the output V _A2 of the falling differentiation circuit 23 is a digital IC
The down counter 24, for example, the up input terminal of the 74193, and the output V _B2 of the falling differentiation circuit 23 are connected to the down clock input terminal.

Here, the falling differentiation circuit 23 includes a capacitor C ₁ connected to the output side of the waveform shaping circuit 22, and
Diode D ₁ and resistor R ₁ connected in parallel with the power supply V _CC
It consists of The waveform shaping circuit 22 may have a circuit configuration as shown in FIG. 3, for example. That is, as shown in FIG. 3A, a comparator 25 is used to input the output signal from the magnetoelectric conversion element 15 to the non-inverting input terminal (+), and the resistance from the power supply V _CC to the inverting input terminal (-). Constant voltage diode ZD via R ₂
A reference voltage having ₁ is input, and a shaped output signal can be obtained.

Further, as shown in FIG. 3B, a comparator 26 with hiss may be used. That is, a resistor R ₃ is provided at the non-inverting input terminal (+), a resistor R ₅ is provided between the non-inverting input terminal (+) and the output terminal, and a resistor R ₄ from the power supply V _CC is provided at the inverting input terminal (−). A reference voltage having a constant voltage diode ZD ₂ is input via the. Furthermore,
A transistor may be used as shown in FIG. That is, the first NPN transistor Tr
The first NPN transistor Tr for inputting the output signal from the magnetoelectric conversion element 15 to the base of ₁ via the resistor R _6.
The emitter of ₁ is grounded and the first NPN transistor T
The collector of r ₁ is connected to power supply V _CC through resistor R ₇ . The emitter of the second NPN transistor Tr ₂ is grounded, and the collector of the _second NPN transistor Tr ₂ is
The second NPN transistor Tr ₂ is connected to the power supply V _CC via the resistor R ₈ and the collector of the first NPN transistor Tr ₁ is connected to the base of the _second NPN transistor Tr ₂ .

Furthermore, the base of the _first NPN transistor Tr ₁ and the collector of the second NPN transistor Tr ₂ are connected via a resistor R ₉ . Further, instead of the fall differentiating circuit 23 described above, a circuit configuration as shown in FIG. 4 can be used. That is, as shown in FIG. 4 (a), using the negative logic OR circuit 28, an input signal V _A1 to one input terminal, to the other input terminal and the inverted input signal V _A1 by the inverter 27 , And through a resistor R ₁₀ to obtain a differential signal output from the output terminal.

Further, as shown in FIG. 4B, the input signal V _A1 is input to one of the input terminals after being inverted by the inverter 29, and the input signal is input to the one input terminal via the delay line 30. A positive logic NAND circuit 31 for inputting V _A1 may be provided. Next, the operation of this magnetic rotation detecting device will be described with reference to FIG. FIG. 2 is an output waveform diagram when the magnetic rotation detection device is powered on.

The timing of I is a waveform when the rotation detection shaft 11 is rotating in the CW direction. At this time, in the multi-pole magnet rotor set 10, only the CW rotor 13 is rotated by the action of the one-way clutch bearing 12,
The CCW rotor 14 does not rotate. Therefore, in the magnetoelectric conversion element A, no change in magnetic force occurs, V _A1 does not change in output, and V _A2 remains in the H state.

The magnetoelectric conversion element B includes a CW rotor 13
The magnetic force changes due to the rotation of. The output of the magnetoelectric conversion element B is shaped into a square wave V _B1 by the waveform shaping circuit 22. The square wave V _B1 falls and is differentiated by the differentiation circuit 23.
It is converted into a pulse V _B2 which becomes L only at the falling edge. The up / down counter 24 counts down when the down input has the rising edge of L → H when the up input is in the H state, and when the up input has the rising edge of L → H when the down input is in the H state. If there is, it will count up. In other words, the up input V _A2 is H during the I period.
Since it is in the state, it counts down at each rising edge of the down input V _B2 .

At time II, since the rotation detection shaft 11 is rotating in the CCW direction, the CW rotor 13 does not rotate, but only the CCW rotor 14 rotates. For this reason,
There is no change in the output of V _B1 and V _B2 remains in the H state. A change in magnetic force occurs in the magnetoelectric conversion element A due to the rotation of the CCW rotor 14. The output of the magnetoelectric conversion element A is converted by the waveform shaping circuit 22 and the square waves V _A1 and V _A2 are converted into a pulse V _{A2 in} which only the falling edge of V _A1 is L by the falling differential circuit 23.

At this time, since the down clock input V _{B2 of} the up / down counter 24 is in the H state, it counts up every rising edge of the up input V _A2 . The rotation angle can be calculated by the rotation direction of the rotation detection shaft 11 and the calculated value of the up / down counter 24 depending on which of the pulses V _A2 and V _B2 changes.

The present invention is not limited to the above embodiments, and various modifications can be made based on the spirit of the present invention, and these modifications are not excluded from the scope of the present invention.

[0023]

As described above in detail, according to the present invention, two multi-pole magnet rotors that rotate only in opposite directions to each other are arranged side by side on the rotation detection shaft, so that outputs can be output in different rotation directions. Since it can be taken out, the rotation direction can be determined and the rotation angle can be detected regardless of the duty.

Therefore, even if the amplitude center voltage of the magnetoelectric transducer changes over time or the magnetization of the multi-pole magnet rotor varies, a magnetic rotation detecting device having stable performance that is not affected by them is realized. it can.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a magnetic rotation detection device showing an embodiment of the present invention.

FIG. 2 is a diagram showing each output waveform of the magnetic rotation detection device showing the embodiment of the present invention.

FIG. 3 is a waveform shaping circuit diagram of the magnetic rotation detection device showing the embodiment of the present invention.

FIG. 4 is a falling differential circuit diagram of another magnetic rotation detection device showing an embodiment of the present invention.

FIG. 5 is a configuration diagram of a conventional magnetic rotation detection device.

FIG. 6 is a diagram showing each output waveform in each state of the conventional magnetic rotation detection device.

FIG. 7 is a diagram showing each state of an output waveform of a conventional magnetoelectric conversion element, a threshold value of a waveform shaping circuit, and an output waveform of a magnetic rotation detection device.

[Explanation of symbols]

 10 Multipole Magnet Rotor Set 11 Rotation Detection Axis 12 One-Way Clutch Bearing 13 CW Rotor 14 CCW Rotor 15 Magnetoelectric Converter 21 Processing Circuit 22 Waveform Shaping Circuit 23 Falling Differentiation Circuit 24 Up / Down Counter 25, 26 Comparator 27 , 29 Inverter 28 Negative logic OR circuit 30 Delay line 31 Positive logic NAND circuit

Claims (1)

[Claims] (A) Two multi-pole magnet rotors arranged side by side on a rotation detection shaft, and (b) a clutch mechanism in which the two multi-pole magnet rotors rotate in only one direction opposite to each other. c) A magnetic rotation detection device comprising a magnetoelectric conversion element facing each of the two multipole magnet rotors, and (d) a processing circuit connected to the magnetoelectric conversion element.