JPH0657080U - Motor rotation detection circuit - Google Patents

Abstract

(57) [Summary] [Object] To provide a rotation detection circuit for a motor, which is advantageous for downsizing and can be configured at low cost. [Structure] 20 is a rotor having magnets 21 in which N and S poles are alternately magnetized in the circumferential direction, and 22u to 22w.
Is a stator coil of each phase, 24u to 24w are rotors 20
This is a Hall element that detects the rotational position of the. Hall element 2
The detection signals of 4u to 24w are supplied to the three-phase motor drive circuit 23, respectively.
To the coil 22u according to the rotational position of the rotor 20.
By controlling the direction and timing of the current flowing through ~ 22w,
The rotor 20 is rotationally driven by the magnetic fields generated by the coils 22u to 22w. Detection signal S of hall elements 24u to 24w
u to Sw are supplied to the mixing circuit 28 via the amplifier circuit 26 and the rectifier circuit 27, and the mixed output signal Sm is supplied to the waveform shaping circuit 29.
The waveform is shaped by to obtain the rotation detection pulse Pr. Unlike the conventional case, it is not necessary to form a black-and-white pattern or a magnetized pattern and to dispose a photodetection element or a magnetic detection element.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a motor rotation detection circuit suitable for being applied to obtain a pulse corresponding to the rotation of a motor in order to control the rotation speed of the motor, for example.

[0002]

[Prior art]

 It has been proposed to drive a reel of a digital audio tape recorder (DAT), a video tape recorder (VTR) or the like with a direct drive motor (DD motor) which is a flat type motor. In this case, in order to control the number of revolutions of the reel and hence the number of revolutions of the motor, conventionally, a pulse corresponding to the rotation of the motor is obtained by the method shown in FIGS. 5A and 5B.

In the method shown in FIG. 5A, a black and white pattern 11 is radially formed on the upper surface of a rotor 10 of a reel motor, and a light emitting element 12A and a light receiving element 12B are arranged so as to face the pattern surface. The pattern surface is irradiated with light, the light reflected by the pattern surface is detected by the light receiving element 12B, and a pulse corresponding to the rotation of the motor is obtained from the detection output of the light receiving element 12B.

In the method shown in FIG. 1B, a magnetizing pattern 13 is formed on the side surface of a rotor 10 of a reel motor, and a magnetic detecting element, for example, a hall element 14 is arranged so as to face the pattern surface. A pulse corresponding to the rotation of the motor is obtained from the detected output.

[0005]

[Problems to be solved by the device]

 However, in the method shown in FIG. 5A, since it is necessary to dispose the light emitting element 12A and the light receiving element 12B facing the pattern surface, a space for mounting them is required, which hinders miniaturization. . Further, since the light emitting element 12A and the light receiving element 12B are required and the black and white pattern 11 is required to be formed, it is expensive.

Further, in the method shown in FIG. 1B, since it is necessary to dispose the Hall element 14 so as to face the pattern surface, a space for mounting the Hall element 14 is required, which hinders miniaturization. Further, since the Hall element 14 is required and the magnetizing pattern 13 is required to be formed, it is expensive.

Therefore, the present invention provides a rotation detection circuit for a motor, which is advantageous in miniaturization and can be configured at low cost.

[0008]

[Means for Solving the Problems]

 This invention has a rotor having a magnet in which N poles and S poles are alternately magnetized in the circumferential direction, and a plurality of motor coils arranged in the circumferential direction so as to face the rotor. , A stator having a magnetic detection element for detecting the rotational position of the rotor, and controlling the direction and timing of the current flowing through the plurality of motor coils according to the detection output of the magnetic detection element. A pulse generating means for generating a pulse according to the rotation of the motor based on the detection output of the element is provided.

[0009]

[Action]

 In this invention, a pulse corresponding to the rotation of the motor is generated by using the detection output of the magnetic detection element that constitutes the motor, and it may be constructed by adding some circuits to the motor. Therefore, it is not necessary to form a black-and-white pattern, a magnetized pattern, or the like as in the conventional case, and to dispose a dedicated photodetection element or magnetic detection element, which is advantageous for downsizing and can be inexpensively constructed.

[0010]

【Example】

 An embodiment of the present invention will be described below with reference to FIG. This example is an example of detecting the rotation of a reel motor (DD motor) which is a flat motor.

In the figure, 20 is a rotor of a reel motor. The rotor 20 has magnets 21 in which N and S poles are alternately magnetized in the circumferential direction. In the magnet 21 of this example, 8 poles (4 sets of N poles and S poles) are magnetized in the circumferential direction at 45 ° division.

Further, 22 u, 22 v, and 22 w are three sets of motor coils that form a stator, and are arranged so as to face the magnet 21 of the rotor 20. One ends of these motor coils 22 u, 22 v, 22 w are commonly connected (Y connection), and the other ends thereof are connected to a three-phase motor drive circuit 23. The motor coils 22u, 22v, 22w of each set are each composed of two motor coils connected in series, and therefore, six motor coils are arranged at 60 ° division in the circumferential direction of the stator. The motor coils of the same set are arranged at opposite positions. A current is supplied from the three-phase motor drive circuit 23 to the motor coils 22u, 22v, 22w of each set.

Further, 24 u, 24 v, and 24 w are Hall elements as magnetic detection elements for detecting the rotational position of the rotor 20. These Hall elements 24u, 24v, 24w are arranged at the same positions as one motor coil constituting each set of motor coils 22u, 22u, 22w. The detection signals Su, Sv, Sw of the Hall elements 24u, 24v, 24w are supplied to the three-phase motor drive circuit 23, respectively, and the directions of the currents flowing in the motor coils 22u, 22v, 22w according to the rotational position of the rotor 20 and Timing is controlled.

FIG. 2 shows a specific configuration of a conventionally known three-phase motor drive circuit 23. 41 is a three-phase logic, 42 is a power supply terminal, 43u, 43v, 43w are PNP type transistors constituting switching elements, Reference numerals 44u, 44v and 44w are NPN type transistors which form a switching element.

A control signal is supplied from the three-phase logic 41 to the bases of the transistors 43u to 43w and 44u to 44w according to the detection signals of the Hall elements 24u to 24w, that is, corresponding to the rotational position of the rotor 20. Thus, the direction and timing of the current flowing through the motor coils 22u to 22w are controlled, and the rotor 20 is rotationally driven by the magnetic field generated by the motor coils 22u to 22w.

3A, 3B, 3C are detection signals Hv, Hu, Hw of the Hall elements 24v, 24u, 24w (Hv, Hu, Hw are signals obtained by waveform-shaping the detection signals Sv, Su, Sw by three-phase logic. , The high level becomes "HIGH" corresponding to the N pole, and the low level becomes "LOW" corresponding to the S pole.), D, E, and F in the figure are collector potentials Lv, 44v of the transistors 44v, 44u, and 44w. Lu, Lw, and G, H, and I in the same figure show base potentials SLv, SLu, SLw of the transistors 43v, 43u, 43w. Although FIG. 3 shows the rotation angle of the rotor 20 from 0 ° to 90 °, it is repeated from 90 ° to 180 °, 180 ° to 270 °, and 270 ° to 360 °. Note that “MID” indicates an intermediate level.

Returning to FIG. 1, the detection signals Su, Sv, Sw of the Hall elements 24u, 24v, 24w are amplified by the amplifier circuit 26 and then supplied to the rectifier circuit 27. The output signals Su ', Sv' and Sw 'of the rectifying circuit 27 are supplied to the mixing circuit 28 and mixed. Then, the mixed output signal Sm of the mixing circuit 28 is supplied to the waveform shaping circuit 29 for waveform shaping, and the output signal of the waveform shaping circuit 29 is derived to the output terminal 30 as the rotation detection pulse Pr.

In the above configuration, when the rotor 20 rotates, the detection signals Sv, Su, Sw of the Hall elements 24v, 24u, 24w become as shown in FIGS. 4B, C, D, respectively, and the output of the rectifying circuit 27 is output. The signals are as shown in E, F and G in the same figure, the mixed output signal Sm of the mixing circuit 28 is as shown in H in the same figure, and 12 pulses / A rotation detection pulse Pr for rotation is obtained. Incidentally, FIG. A shows the magnetic poles of the magnet 21 facing the Hall element 24v.

As described above, in this example, the rotation detection pulse Pr is obtained by using the detection signals Su to Sw of the Hall elements 24u to 24w, and the amplification circuit 26, the rectification circuit 27, the mixing circuit 28, and the waveform shaping. It can be configured by adding some circuits such as the circuit 29, and it is not necessary to form a black-and-white pattern or a magnetized pattern and to dispose a dedicated photodetection element or magnetic detection element as in the conventional case. In addition, it is advantageous for downsizing and can be constructed at low cost.

In the above embodiment, the magnet 21 of the rotor 20 is magnetized to have 8 poles in 45 ° division, and the stator is divided into 6 motor coils (3 motor coils 22u, 22v, 22w in 60 ° division). ) Is arranged, the number of magnetized poles of the magnet 21 and the number of motor coils are not limited to this.

Further, although the above embodiment is an example of detecting the rotation of the reel motor, it is needless to say that the rotation of the motor having other similar structure can be detected in the same manner.

[0022]

[Effect of device]

 According to this invention, a pulse corresponding to the rotation of the motor is generated by using the detection output of the magnetic detection element that constitutes the motor, and since some circuits can be added to the motor, As described above, it is not necessary to form a black-and-white pattern, a magnetized pattern, etc., and to dispose a dedicated photodetection element or magnetic detection element, which is advantageous for downsizing and is inexpensive.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a motor rotation detection circuit according to the present invention.

FIG. 2 is a configuration diagram showing a specific configuration of a three-phase motor drive circuit.

FIG. 3 is a timing chart showing the operation of the example of FIG.

FIG. 4 is a waveform diagram for explaining the operation of the example of FIG.

FIG. 5 is a diagram for explaining a conventional example.

[Explanation of symbols]

 20 rotor 21 magnet 22u, 22v, 22w motor coil 23 three-phase motor drive circuit 24u, 24v, 24u Hall element 26 amplification circuit 27 rectifier circuit 28 mixing circuit 29 waveform shaping circuit 30 output terminal

Claims (1)

[Scope of utility model registration request] 1. A rotor having a magnet in which N poles and S poles are alternately magnetized in a circumferential direction, and a rotor arranged facing the rotor and having a plurality of motor coils in the circumferential direction, A motor having a stator having a magnetic detection element for detecting the rotational position of the rotor, and controlling the direction and timing of the current flowing through the plurality of motor coils according to the detection output of the magnetic detection element, A rotation detecting circuit for a motor, comprising pulse generating means for generating a pulse according to the rotation of the motor based on the detection output of the magnetic detecting element.