JPH02211047A - Dc commutatorless motor - Google Patents

Abstract

PURPOSE:To omit a special PG signal detecting element by using three position detecting signals necessary for circuit commutated signal detection basically to obtain the PG signal. CONSTITUTION:Circuit commutated signal detecting position detecting elements 2, 3 and 4 consisting of Hall elements are provided at 120 intervals, their output enter into arithmetic circuits 13, 14 and 15 through amplifiers 10, 11 and 12, and stator windings 5, 6 and 7 are driven by operational output through driving circuits 16, 17 and 18. The difference in the output adjacent three position detectors 2, 3 and 4 is equal to the second output of the arithmetic circuits, so that the difference is led to an absolute value adder 19 to make absolute value addition, and three pulses are obtained in every rotation by comparing with a prescribed level with a comparator 22. A phase selective circuit 21 is turned ON in case the output of the position detecting element 4 is higher than the output of the position detecting elements 2 and 3, and an analog switch 24 outputs the output of one pulse in every rotation by passing the output of the comparator 22 at that time only.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a three-phase DC non-commutator motor, which is suitable for cylinder drum drive motors of video tape recorders (VTRs), spindle motors of floppy disk drives, etc. The present invention provides a DC non-commutator motor.

2. Description of the Related Art In recent years, DC non-commutator motors have come into widespread use in many VTRs and floppy disk devices. In the cylinder drum drive motors of these VTRs, a pulse signal (hereinafter referred to as the PG double signal) is sent once every rotation of the rotor of the motor connected to the drum in order to detect the rotational position of the rotating magnetic head of the drum. I need.

Also, in a spindle motor that drives a floppy disk drive device, a PG multiplied signal called an index pulse is required once per rotation in order to define the writing start position of the floppy disk.

A conventional motor configuration having means for obtaining such a PG multiplied signal is shown in FIG.

A rotor magnet 40 is fixed to the rotor yoke 34,
Further, a PG magnet 41 is fixed to the outer periphery of the rotor yoke 34, and a Hall IC 42 is attached to the stator board 37 facing the magnet 41. With this configuration, each time the rotor rotates once, the Hall IC detects the magnetic flux of the PG magnet and generates a PG multiplied signal.

Note that an element 44 for detecting the rotational position of the rotor is provided on a portion of the stator substrate 37 facing the rotor magnet 40.
is installed to control the drive.

Problems to be Solved by the Invention However, in the conventional configuration as described above, since the PG magnet is attached to the rotor with adhesive or the like,
This results in an increase in the number of processes and the number of parts.
Providing a magnetic sensing element for G pulse detection has the problem of increasing material costs and assembly man-hours, and in order to obtain the necessary sensitivity in terms of performance, it is necessary to use ordinary ferrite etc. Since magnets lack magnetic flux, expensive rare earth magnets are used as PC magnets, which has the problem of increasing costs.

In order to solve the above-mentioned problems, the present invention utilizes signals obtained from three position detection elements basically required to create a three-phase distribution signal in a three-phase non-commutator motor. The present invention provides a commutatorless motor that makes it possible to obtain a PG multiplied signal without increasing the number of parts.

Means for Solving the Problems In order to solve the above-mentioned conventional problems, the non-commutator motor of the present invention includes a three-phase stator winding, a two-phase stator winding,
a rotor with n magnetic poles magnetized, and a rotor facing this rotor;
The position detecting element includes three position detecting elements that detect the rotational position of the rotor, and a drive circuit that differentially synthesizes the output signals and switches the current to the three-phase stator windings. A part of the magnetic pole of the rotor facing the rotor is provided with a magnetized band of opposite polarity or non-magnetic, and the absolute values of the three-phase signals obtained by differentially combining the output signals of the position detection elements are added. The motor is equipped with a detection signal processing circuit that detects a PG multiplied signal once per rotation by comparing its output signal with a predetermined reference level.

Operation The present invention utilizes three position detection signals that are basically necessary for detecting commutation signals for drive control in a three-phase non-commutator motor consisting of four or more magnetic poles with the above-described configuration. , it is possible to obtain a PG multiplied signal once per rotation.

EXAMPLE Hereinafter, a DC commutatorless motor according to an example of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing the basic configuration of a motor in an embodiment of the present invention. In FIG. 1, reference numerals 2, 3.4 indicate position detection elements made of Hall elements, which are arranged with a mechanical phase difference of 120°. In addition, 5, 6, and 7 are stator windings that are mechanically arranged with a phase difference of 120°, and ■ is a magnetized part in which 4 magnetic poles (n = 2) are magnetized in the rotor. A south pole magnetized band a is provided on a part of the north pole of the position detection track facing the position detection element 2.3.4.

FIG. 2 is a circuit block diagram in an embodiment of the present invention.

In the figure, reference numerals 2, 3.4 are the position detection elements shown in FIG.

Further, the other end of the DC power supply 8 is grounded.

10.11.12 are amplifiers connected to the position detection elements 2, 3.4, respectively; 13, 14.15. is amplifier 10.
11.12. Subtraction circuit connected with, 16.17.18
are connected to the subtraction circuits 10.11.12, respectively, and the current drive circuits, 1, connected to the motor stator windings 5, 6.7.
9 is an absolute value addition circuit connected to the subtraction circuit 16, 17.18, 21 is a phase selection circuit connected to the amplifiers 10, 11.12, 22 is a comparator connected to the absolute value addition circuit 19, and 23 is an absolute value addition circuit connected to the subtraction circuit 16, 17.18. An analog switch 24 is connected to the phase selection circuit 21 and the comparator 22, and 24 is a PG signal detection circuit composed of the phase selection circuit, the comparator 22, and the analog switch 23.

Regarding the DC non-commutator motor configured as above,
The operation will be explained below using FIG. 2, FIG. 3, and FIG. 4. Here, FIG. 3 shows the PG signal detection circuit 24 of FIG.
FIG. 4 shows waveforms of various parts of the drive device shown in FIG. 2.

First, the operation will be explained with reference to the basic configuration diagram of the present invention shown in FIG. 1. As the rotor 1 rotates, for example, clockwise, the first . Second. third position detection element, 2
．． 3.4 is an output that responds in response to the magnetized magnetic poles of the opposing rotor, and the signal drops when each position detection element 2, 3, 4 faces the magnetized zone a as shown in Figure 4A. H+,
Hg and H3 are output, and the output is amplified by 10.11.12 (the gain is a constant). 13, 14, and 15 are subtracting circuits, and the output of the amplifier 10 and the output voltage KH+, KHz of the amplifier 11 are inputted to the subtracting circuit 13, subtracted, and a voltage of P+ (=KH+ KHz) is output. The output voltages KH2 and KH3 of the amplifiers 11 and 12 are input to the subtraction circuit 14 and subtracted to give Pg (=
A voltage of KHg KH3) is output. Similarly, the subtraction circuit 15 has output voltages KH3, KH,
is input and subtracted, resulting in F3 (= K H3 - K H+
) is output.

The subtracting circuits 13, 14, and 15 are each configured to obtain two output voltages, one of which is supplied to a drive circuit consisting of three differential circuits and a current amplification circuit, and is used to control the rotation of the motor stator winding. Current current IP+, IPg.

It becomes 1P3. The other output voltage P I e P R
#P3 is input to the absolute value addition circuit 9, but the output voltage PIF2.#P3 shown in FIG. Absolute value addition output Sl of F3 (St = IP + l + lPg l + P31
) becomes a waveform Sl in which the signal level drops at the portion of the magnetized band a, as shown in FIG.
By inputting a predetermined voltage V↑ to the other input terminal and comparing it, three pulses Pz are output per rotation as shown in the fourth diagram. Here, the phase selection circuit 21 includes a transistor 2 as shown in the circuit of FIG.
5゜26.27,28. The output signals of the amplifiers 10 and 11.12 are input to the bases of the transistors 25 and 26.27, and the magnitude relationship of the output signals H+, Hz, and H3 of the position detection elements is compared. , the transistor 28 is turned off only in the range (240° to 360°) where the third position detection element H3 is larger than the other Hl and Hg, and the transistor 28 is turned off in the other range (0 to 240''). By turning on, the PG at a position (240” to 360°) is selectively selected from the pulse P2.
The pulses are output as the output of the transistor 30 as a PG multiplied signal once per revolution as shown in FIG. 4E.

As is clear from the above explanation, according to the present invention, even in a three-phase non-commutator motor having four or more magnetic poles, a PG multiplied signal is generated once per rotation from signals obtained from three position detection elements. As compared with the conventional method, it is possible to obtain excellent effects such as a reduction in the number of detection elements such as PG magnets and magnetic sensing elements, and a reduction in the number of assembly steps.

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

FIG. 5 is a block diagram of another embodiment of the invention.

In the same figure, 2, 3.4 are position detection elements, 10.11
．． 12 is an amplifier, 13.14.15 is a subtraction circuit, 16,
17.18 is the current drive circuit, 5°6.7 is the stator winding,
24 is a PG signal detection circuit with a built-in phase selection circuit 21;
The above configuration is the same as the configuration of the block diagram in FIG.

The difference from the configuration shown in FIG. 2 is that an adder circuit 20 is connected to the outputs of the amplifiers 10, 11 and 12 to output a PG multiplied signal.The operation will be described below using the waveform diagram in FIG. I will explain.

Similarly to the first embodiment of the invention, the amplifier 10°11.12
The outputs include the signal outputs H+, H2, and H shown in FIG. 6A.
Outputs 3. The signal output is transmitted to the subtraction circuit 13, 14, 15° drive circuit 16, 17, 18 as in the first embodiment.
to the stator winding 5.6.7 via I p+ l I
The current is distributed as pg l r p3 to become a signal to drive the motor, and the signals H+, H2, and H3 are input to the adder circuit 20, and the signals are inputted into the adder circuit 20, and the signals are inputted into the adder circuit 20, and the signals are inputted into the adder circuit 20, and the signals are inputted into the adder circuit 20, and the signals are inputted into the adder circuit 20.
Outputs the PG times signal. The signal is compared with the voltage vT in the comparator 22, and furthermore, only the H3 drop signal is selected in the phase selection circuit 21, and a PG multiplied signal once per rotation is outputted to the output of analog SW 23. .

As explained above, in this embodiment as well, the PC is detected once per rotation by the signals obtained from the three position detection elements.
It is now possible to obtain a signal, and the PG is lower than that of the conventional method.
It is possible to obtain the excellent effects of reducing the number of detection elements such as magnets and magnetic sensing elements, and reducing the number of assembly steps.

In addition, in the above-mentioned embodiment of the present invention, the first and second
．． The third position detecting element is mechanically arranged at an angle of 120 degrees, but generally in a three-phase non-commutator motor having more than 2n (where n is a natural number of 2 or more) kinds of magnetic poles, three position detecting elements are used. It goes without saying that the same effect as in the embodiment can be obtained even if the elements are arranged with an angle difference of 120° x K/n (where K is a natural number that is a multiple of 3 or less).

Effects of the Invention As described above, the present invention provides a DC non-commutator motor configured to detect the magnetic flux of a rotor magnetized with 2n magnetic poles using a position detection element and distribute current to the motor. A part of one of the 2n magnetic poles is magnetized with reverse polarity or non-magnetic, and the signals are detected by the three position detection elements and summed and synthesized, thereby generating a normal signal. without affecting current distribution to the motor.
It is possible to obtain a PG multiplied signal once per revolution, making it possible to reduce the cost and size of drive motors for VTR devices and floppy disk devices.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of an embodiment of the present invention, Fig. 2 is a block diagram of the first embodiment of the invention, and Fig. 3 is a block diagram of the PG in Fig. 2.
A wing body circuit diagram of the signal detection circuit, FIG. 4 is a signal waveform diagram of each part in FIGS. 2 and 3, FIG. 5 is a block diagram of the second embodiment of the present invention, and FIG. A signal waveform diagram of each part in the figure, and FIG. 7 is a sectional view of a conventional DC non-commutator motor. 1... Rotor, 2, 3.4... Position detection element, 5.6.7... Stator winding, 10, 1
1.12...Amplifier, 13,14.15・Old・
・Subtraction circuit, 16°17.18...drive circuit,
24. Old... PG detection circuit. Figure 1 1-11 Rotation Chi (Rotamak, Sheep,, To) υ, 4---
a device IL output element

Claims (3)

[Claims] (1) A three-phase stator winding, facing the stator winding,
A rotor magnetized with 2n (where n is a natural number of 2 or more) magnetic poles, three position detection elements facing the rotor and detecting the rotational position of the rotor, and the position detection element first, second, and third amplifiers that amplify the respective output signals of the amplifiers; and first, second, and third amplifiers that synthesize the differences between the respective outputs of the amplifiers.
A third subtraction circuit, and a drive circuit that amplifies the output of the subtracter and supplies current to each of the three-phase stator windings, In part,
A DC non-commutator motor with reverse polarity or non-magnetic magnetized bands. (2) The three position detection elements are arranged at intervals of 120 degrees in electrical angle, and include an adder in which the outputs of the first, second, and third subtraction circuits are added and combined, and the output of this adder. 2. The DC non-commutator motor according to claim 1, further comprising a detection signal processing circuit that detects one PG pulse per rotation by comparing the signals at a predetermined reference level. (3) The three position detection elements are arranged at intervals of 120 degrees in electrical angle, and include an adder in which the outputs of the first, second, and third amplifiers are added and combined, and the output of this adder. 2. The DC non-commutator motor according to claim 1, further comprising a detection signal processing circuit that detects one PG pulse per rotation by comparing the signals at a predetermined reference level.