JPH0297290A - Detector for direction of rotation of motor - Google Patents

Abstract

PURPOSE:To detect the direction of rotation of a motor by setting the duty ratio of the rotary signal of a rotary-signal generating means at a value different from 50% and providing the output side of the rotary-signal generating means with a duty-ratio discriminating means. CONSTITUTION:The periphery of the rotary section of a motor 1 is magnetized so that N and S poles conduct outputs at a duty ratio different from 50%. A flux sensing element is installed to a rotary-signal generator 4, the magnetic flux of N and S poles is sensed with the revolution of the motor 1, and the direction of rotation of the motor 1 can be detected from the output level of a comparator 8.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a rotation direction detection device for a motor that rotates in both forward and reverse directions, such as a capstan drive motor of a VTR.

[Conventional technology]

As a conventional device for detecting the rotational direction of this type of motor, the National Technical Report (Nation
al Technical Report) Vol.
28, Nl3.

(1982, 6) requires two rotating pulses, each with a phase difference of 90 degrees from each other, and sampling the other pulse on the rising or falling edge of one pulse, as shown in P, 147. The direction of rotation was detected by

[Problem to be solved by the invention]

In the above-mentioned conventional technology, generators for two phases of rotational pulses are required, and in some cases, an amplifier dedicated to each rotational pulse is required.

Furthermore, a sampling circuit (for example, a flip-flop circuit) and the like are required.

As described above, there is a problem in that special or separate means or circuits must be provided in order to detect the rotational direction of the motor.

SUMMARY OF THE INVENTION An object of the present invention is to provide a motor rotation direction detection device that can detect the rotation direction using simpler means (circuits).

[Means to solve the problem]

The above purpose is to change the rotation pulse generation mechanism provided in the rotating part of the motor to a value where the duty ratio of the generated pulses is different from 50% (
This is achieved by arranging the duty ratio to be larger or smaller than 50 inches, and providing means for detecting that the duty ratio is reversed when the motor rotates in the forward direction and in the reverse direction.

[Effect]

For example, the duty ratio of the rotation pulse of the motor during normal rotation is set to 30%. In this case, the duty ratio during reverse rotation is 70%. If the amplitude of this rotation pulse is set to ■ and is smoothed with a CR filter, the output will be 3V/10 during forward rotation.
, 7V/10 during reverse rotation, and the direction of rotation of the motor can be easily determined from this potential difference.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a configuration diagram illustrating an embodiment of a motor rotation direction detection device according to the present invention, in which 1 is a motor, 2 is a drive signal amplifier for driving the motor, and 3 is a signal input terminal for controlling the motor speed. , 4 is a rotation signal generator that generates a frequency proportional to the rotation speed of the motor, 5 is an amplifier, 6 is a resistor, 7 is a capacitor, 8 is a comparator, and 9 is a reference voltage source.

In the figure, the periphery of the rotating portion of the motor 1 is magnetized with N poles and S poles in a pattern with intervals that provide an output with a desired duty ratio. Further, the rotation signal generator 4 includes a magnetic flux sensing element such as a magnetoresistive element, a Hall element, a magnetic head, etc., and senses the magnetic flux from the magnetized N pole and S pole as the motor 1 rotates. This is converted into an electrical signal.

FIG. 2 is an operational waveform diagram of FIG. 1, where 10 is a waveform during normal rotation and 11 is a waveform during reverse rotation.

Waveform 10 has the above duty ratio of 30%, and waveform 11 has a duty ratio of 7.
It shall be 0chi.

1 and 2, when an appropriate voltage for driving the motor is applied to the signal input terminal 3, the amplifier 2 sends a driving current to the motor 1, and the motor 1 rotates. , the duty ratio is 30 depending on the rotation direction.
% or 70% pulse signal is applied to the amplifier 5. The pulse signal amplified by the amplifier 5 is smoothed by a smoothing circuit consisting of a resistor 6 and a capacitor 7, and is then smoothed at 3V/10 or 7V.
A voltage of V/10 is applied to one input of the comparator 8.

The above smoothed voltage when the motor 1 rotates in the normal direction is waveform 10 in FIG.
As shown in , it is 3V/10, so if the voltage of the reference voltage source 9 of the comparator 8 is V/2, the output of the comparator 8 is L.
``level'', and when the motor 1 is in reverse rotation, the output of the comparator 8 becomes ``H'' level.

Thereby, the rotational direction of the motor 1 can be detected based on the level of the output of the comparator.

〔Effect of the invention〕

As explained above, according to the present invention, detection of the rotation direction of a motor can be realized with a small number of parts and a simple configuration, and it is possible to significantly improve reliability and improve economic efficiency. Therefore, it is possible to provide a motor rotation direction detection device with excellent functions without the drawbacks of the above-mentioned prior art.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of a motor rotation direction detecting device according to the present invention, and FIG. 2 is an operational waveform diagram outside the box. 1...Motor 2...Drive signal amplifier 3
...Drive signal input terminal 4...Rotation signal generator 5...
・Amplifier 6...Resistor 7...Capacitor 8...Comparator 9...Reference voltage source

Claims (1)

[Scope of Claims] 1. In a motor rotation direction detection device comprising a motor and rotation signal generation means for generating a rotation signal with a frequency proportional to the rotation speed of the motor, the duty of the rotation signal of the rotation signal generation means The motor is characterized in that the ratio is set to a value different from 50%, a duty ratio determining means is provided on the output side of the rotation signal generating means, and the rotation direction of the motor is detected by the duty ratio determining means. Motor rotation direction detection device. 2. In claim 1, the rotation signal generating means comprises magnetization of N poles and S poles arranged alternately in a pattern corresponding to the duty ratio on the periphery of the rotating part of the motor, and a magnetic flux sensor for detecting the magnetic flux of this magnetization. What is claimed is: 1. A rotational direction detection device for a motor, comprising: an element.