JPH0777520B2 - Motor speed detection method - Google Patents

Description

The present invention relates to a rotation speed detection method for controlling the rotation speed of a motor in a washing machine or the like.

[Conventional technology]

As a motor encoder device for detecting the number of rotations of a motor, a reflector provided with a slit for rotating in synchronization with the rotor of the motor to detect an energized position, and a slit for detecting the slit of the reflector It is known that the sensor is arranged on a mounting plate facing the reflection plate.

An example of this is shown in FIGS. 7 to 11, and a disc-shaped reflector (3) that rotates in synchronization with the rotor shaft (5) of the rotor (4) of the motor is attached to the rotor shaft (5) of FIG. As shown, slits (8a) and non-slits (8b), which are equally divided in the circumferential direction, are alternately formed on the outer periphery of the reflector (3). In the example shown, both the slit (8a) and non-slit (8b) are 10
It has a width of degrees.

A sensor mounting plate (2) is disposed facing the reflection plate (3) by bossing from the encoder case (1) mounted on the motor frame (7).
As shown in FIG. 8, a sensor (6e) for detecting the slit (8a) and the non-slit (8b) was attached.

The sensor (6e) is configured as a reflection type sensor having a phototransistor that turns on and off depending on the presence or absence of reflection on the reflector (3) as shown in FIG. 10, and the output signal from the phototransistor is compared by a comparator (6e). It was introduced in 9a).

Next, the operation will be described. When the rotor shaft (5) rotates, the reflector plate (3) integrally attached to the rotor shaft also rotates, and as a result, the reflector plate (3) is below the sensor (6e). The slits (8a) and the non-slits (8b) are alternately positioned, and the reflective state and the non-reflective state are alternately displayed. The sensor (6e) is in the reflective state and the transistor of the internal circuit is turned on to cause the non-reflective state. Turn off in the state.

The on / off signals are input to the input terminal of the comparator (9e), where the on / off signals are compared with the reference voltage, and a rectangular wave output signal as shown in FIG. 11 is output.

By the way, if the information converted into a digital signal of the output of the comparator is introduced into a control device (not shown) and the information is calculated by the control device, the rotation speed of the rotor (4) can be detected.

[Problems to be Solved by the Invention]

In this way, in the conventional method of detecting the number of rotations of the motor by the encoder device for the motor, the output frequency of the sensor (6e) increases as the motor rotates at high speed,
Incorporating this output into the motor control device may increase the load on the control device.

In order to cope with this, it is required to complicate the circuit configuration and increase the size of the device.

It is an object of the present invention to provide a method for detecting the number of rotations of a motor, which eliminates the inconveniences of the conventional example, reduces the load on the control device, and can downsize and simplify the device.

[Means for Solving the Problems]

In order to achieve the above object, the present invention provides a reflector having a slit that rotates in synchronization with a rotor of a motor and a sensor for detecting the slit of the reflector, which is provided on a mounting plate facing the reflector. In the method of detecting the number of rotations of a motor using the encoder device for a motor described above, the slits of the reflector are two kinds of slits for detecting the energized position and a slit for detecting the amount of rotation, and detect the energized position. Equipped with a magnetic pole position detection circuit of the motor corresponding to the slit for detecting, and a speed detection circuit corresponding to the slit for detecting the amount of rotation, when the motor is rotating at low speed, the speed signal from the speed detection circuit is taken into the control device. ,
The purpose is to switch so that the magnetic pole position detection signal from the magnetic pole position detection circuit is taken into the control device during high speed rotation.

[Action]

According to the present invention, when the speed of the motor is high, the magnetic pole position detection signal from the magnetic pole position detection circuit is switched so as to be taken into the control device, so that the frequency becomes lower than the frequency of the speed signal, and the load on the control device can be reduced. it can.

〔Example〕

 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a plan view of a rotary plate showing an embodiment of a motor encoder device used in a motor rotation speed detection method of the present invention, FIG. 2 is a plan view of a sensor mounting plate of the same as above, and FIG. Since the entire configuration of the encoder device is the same as that already described for the conventional example of FIG. 7 in a side view with parts cut away, detailed description thereof is omitted here. Further, in the figure, the same components as those of the conventional example described with reference to FIGS. 7 to 11 are designated by the same reference numerals.

A disk-shaped reflector (3) that rotates in synchronism with this is attached to the rotor shaft (5) of the rotor (4) of the motor, and the reflector (3) has an equal angle of 10 degrees in the circumferential direction on the outer circumference of the reflector. Although the slits (8a) and the non-slits (8b) which are divided are alternately formed, the present invention is the same as the above-mentioned conventional example. However, in the present invention, the reflector (3) further includes a rotor (4) which is a permanent magnet. N
Circular slits (10) for 30 degrees corresponding to either the pole or the S pole are provided with a width of 30 degrees between them.

On the other hand, as shown in FIG. 2, the sensor mounting plate (2) has three sensors (6a) (6b) for detecting the slit (10).
(6c) are arranged on the same circumference with the same radius as the slit (10) at equal intervals of 15 degrees, and the detection sensors (6d) for the slit (8a) are arranged near the outer periphery of the mounting plate (2). did. As shown in FIG. 6, the configuration of these sensors (6a) (6b) (6c) (6d) is the same as that described with reference to FIG.

In this way, when the motor rotates, the sensor (6a)
(6b) and (6c) are offset by 15 degrees, so
The positions of the slits (10) shifted by 15 degrees are detected, and the sensors (6a) (6b) (6
It is output from the comparators (9a) (9b) (9c) of c) and the magnetic pole position of the rotor (4) is detected.

The slit (8a) and the non-slit (8b) are alternately located in the sensor (6d), and the reflective state and the non-reflective state are alternately displayed. The sensor (6e) is in the reflective state and the transistor of the internal circuit Turns on and turns off in the non-reflective state.

The on / off signals are input to the input terminal of the comparator (9d), where the on / off signals are compared with the reference voltage, and a rectangular wave output signal as shown as output 4 in FIG. 5 is output.

Therefore, according to the present invention, when the motor is rotating at a low speed as shown in FIG. 4, the speed signal of the output 4 shown in FIG. 5 from the speed detecting circuit by the sensor (6d) and the comparator (9d) is taken into the control device to rotate the motor. Is calculated.

On the other hand, during high speed rotation, it controls the magnetic pole position detection signals (outputs 1 to 3 in FIG. 5) from the magnetic pole position detection circuit consisting of the sesa (6a) (6b) (6c) and the comparators (9a) (9b) (9c). It is taken into the device and the number of rotations is calculated by this.

〔The invention's effect〕

As described above, the method for detecting the number of rotations of the motor of the present invention is such that the reflector that rotates in synchronization with the rotor of the motor and that has the slit and the sensor for detecting the slit of the reflector face the reflector. When using the motor encoder device that is mounted on the mounting plate, when the motor is high speed, it is switched so that the magnetic pole position detection signal from the magnetic pole position detection circuit is taken into the control device, so it is lower than the frequency of the speed signal. Since the frequency becomes the frequency, the burden on the control device can be reduced, and the size can be reduced.

[Brief description of drawings]

FIG. 1 is a plan view of a reflector of an encoder device for a motor used in the method for detecting the number of rotations of a motor of the present invention, FIG. 2 is a plan view of a sensor mounting plate of the same as above, and FIG. 3 is a part of the encoder device for a motor. FIG. 4 is a cutaway side view, FIG. 4 is a flow chart showing an embodiment of the method of the present invention, FIG. 5 is a waveform diagram of the output signal of the comparator, FIG. 6 is a circuit configuration diagram of the sensor, and FIG. 7 is a conventional motor. FIG. 8 is a plan view of the sensor mounting plate of the same as above, FIG. 9 is a plan view of the reflecting plate of the same as above, FIG. 10 is a circuit configuration diagram of the sensor, and FIG. It is a timing diagram of the output signal of the comparator. (1) …… Encoder case (2) …… Mounting plate (3) …… Reflector, (4) …… Rotor (5) …… Rotor shaft (6a) to (6e) …… Sensor (7) …… Motor frame, (8a) …… Slit (8b) …… Non-slit (9a) to (9e) …… Comparator (10) …… Slit

Front page continuation (72) Inventor Yoshiro Nagasu 1-1-1, Yamate, Funabashi City, Chiba Nihon Kentetsu Co., Ltd. Funabashi Manufacturing Co., Ltd. (56) Reference JP-A-49-129814 (JP, A) JP-A-SHO 63-240386 (JP, A) JP-A-63-277486 (JP, A) Actually opened 2-94493 (JP, U) Actually opened 64-50315 (JP, U)

Claims (1)

[Claims] 1. An encoder device for a motor, which rotates in synchronism with a rotor of a motor and has a reflecting plate having a slit and a sensor for detecting the slit of the reflecting plate, which is arranged on a mounting plate facing the reflecting plate. In the method of detecting the number of rotations of a motor using, the slits of the reflector are two kinds of slits, one for detecting the energized position and the other for detecting the amount of rotation, which corresponds to the slit for detecting the energized position. The motor magnetic pole position detection circuit and the speed detection circuit corresponding to the slit for detecting the rotation amount are provided. When the motor rotates at a low speed, a signal from the speed detection circuit is taken into the control device, and when the motor rotates at a high speed, the magnetic pole is detected. A method for detecting the number of rotations of a motor, characterized by switching so that a signal from a position detection circuit is taken into a control device.