JPS60213291A - Brushless dc motor - Google Patents

Abstract

PURPOSE:To generate a rotary phase reference signal without increasing the numbers of parts and steps and the cost by generating a rotary phase reference signal with the outputs of the first and second signal generating means for generating pulse signals of the prescribed number at every one revolution of a rotor. CONSTITUTION:The first signal generating means 7 generate N pieces of pulse signals at every one revolution of a rotor 1A, and the second signal generating means 8 generate M pieces of pulse signals at every one revolution of a rotor 1A. These pulse signals are input to a rotary phase reference signal generator 9A, and one pulse signal is generated at every one revolution of the rotor 1A. The relation of N, M is set to M=AXN+ or -1 in case of M>N, and to N=BXM + or -1 (where A, B, M, N are natural numbers of 1 or larger) in case of M<N.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a brushless DC motor in which the rotational phase of a rotor is controlled, and is effective for use as a drive source for various audio equipment, video equipment, etc. .

Conventional configuration and its problems Brushless DC motors do not use a brush commutator, so there is no commutation noise, and they have a long life and high reliability, and have been widely used in audio and video equipment. There is. In particular, a rotary head driving motor of a rotary head type video tape recorder controls the phase of a reference signal and the rotary head in order to scan a fixed position on a magnetic tape.

For this purpose, a rotational phase reference signal generating means for generating a signal indicating the mechanical rotational phase of the rotating head and the rotating head is incorporated.

Therefore, in conventional brushless DC motors in which the rotational phase is controlled, it is necessary to incorporate rotational phase reference signal generation means, which increases the number of parts, man-hours, and cost, and makes it difficult to downsize. Ta.

OBJECTS OF THE INVENTION An object of the present invention is to take such points into consideration, and to provide a method in which the relationship between the number of pulses N per rotation of the rotor of the first signal generating means and the second signal generating means and M is such that M>N. In the case, M=AxN+1 (1m)M (N (
7), then N=BXM+1 (([1jl) (however, A
, B, M, and N are natural numbers of 1 or more), thereby providing a brushless DC motor that can generate a rotational phase reference signal. In particular, the second signal generating means is composed of a first signal generating means for processing the output of the position signal generator or the back electromotive force of the drive coil, and a speed detecting means for controlling the rotational speed of the rotor. With this, it is possible to provide a brushless DC motor that generates a rotational phase reference signal without increasing the number of parts, man-hours, or cost, and that can be easily miniaturized.

Structure of the Invention In order to achieve the above object, the brushless DC motor of the present invention includes: a multi-pole magnetized permanent magnet attached to a rotor; a multi-phase drive coil disposed on a stator; a position signal generator that generates position signals of multiple phases corresponding to rotational positions of the rotor; a drive circuit that sequentially excites the drive coils of the multiple phases in response to the position signals of the multiple phases; a first signal generating means for generating N pulse signals for each revolution of the rotor; a second signal generating means for generating M pulse signals for each revolution of the rotor; A rotational phase reference signal generating circuit is provided which generates one pulse signal for each rotation of the rotor based on the output of the second signal generating means, and the relationship between the N and M is expressed as follows: M) In the case of H, M = AXN±1 (pieces) M (Nt7), then N=BXM±1 C pieces) (however, 8, B, M, and N are natural numbers of 1 or more), which allows the rotational phase reference signal to be It happens.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the brushless DC motor of the present invention.

In FIG. 1, 1A is a rotating shaft, and 1B is an 8-pole magnetized permanent magnet, which constitutes a rotor.

2.3.4 is a three-phase drive coil, and 6 is a Hall element 61°52.53 disposed facing the magnetized surface of the permanent magnet 1B.
6 is a drive circuit that sequentially excites the three-phase drive coils 2, 3.4 in accordance with the output of the position signal generator 5. , 7 is a Hall element 61 and its output is shaped into a waveform,
The first signal generating means consists of a comparator 71 that outputs four (N=4) pulse signals for each rotation of the rotor, 8A is a permanent magnet attached to the rotating shaft and magnetized with 10 poles, 8B is a This is a frequency generator that detects the magnetic flux of the permanent magnet 8A, shapes it into 6 (M = 6) pulse signals for each rotation of the rotor, and outputs it. 8 is composed of the permanent magnet 8A and the frequency generator 8B. This is a speed detection means.

The second signal generating means 9A generates a signal every one rotation of the rotor based on the outputs of the first signal generator 7 and the second signal generating means 8.
A rotational phase reference signal generation circuit that outputs pulse signals of
Reference numeral 10 denotes a DC voltage source that supplies a power supply voltage M to the three-phase drive coil 2°3.4.

Next, the operation of this embodiment will be explained using the specific configuration diagram of the rotational phase reference signal generation circuit shown in FIG. 2 and the main signal waveform diagram shown in FIG. 3. First, the drive circuit 6 supplies a constant voltage VH to the position signal generator 50 Hall element 61゜52.53, and sequentially drives the three-phase drive coil 2, 3. Excite 4.

Therefore, the permanent magnet 1B rotates. Since various well-known circuits can be used as the drive circuit 6, detailed description thereof will be omitted here.

As the permanent magnet 1B rotates, the Hall element 61 of the position signal generator 6 generates an alternating signal d corresponding to the number of pairs of magnetized poles. By manually inputting the signal a to the first signal generating means 7 constituted by the comparison booklet 1, one of the nine rotors is
Four (N=4) pulse signals (signal b in Fig. 3) per rotation.
). The second signal generating means 8 is a permanent magnet 1.
Similarly to B, the magnetic flux of the permanent magnet 8A attached to the rotating shaft 1A is detected, and six (M=5) pulse signals (signal C in FIG. 3) are output for each rotation of the rotor. Also, signal C
is also a signal that controls the rotational speed of the rotor. here,
The phase relationship between the output of the first signal generating means 7 (signal b) and the output of the second signal generating means 8 (signal C) is shown in FIG.

FIG. 2 is a specific configuration diagram of the rotational phase reference signal generation circuit 9A. By connecting a signal to the data terminal of the p-type flip-flop 91, a signal C to the clock terminal CK, and a ground point to the upper setter S and reset terminal R, a signal d is obtained at the output terminal Q. In addition, the broken line part is
This is the case where the rise of the signal C occurs when the signal C is at the "High" level, and the solid line is the case when the signal C is at the "Low" level.

The inverted signal of the signal d (that is, the Q output of the flip-flop 91) is applied to the terminal CK of the D-type flip-flop 92, and the circuit power supply voltage ■ is applied to the D-type flip-flop 92. c, ground point at S terminal, R terminal 1
By applying a signal to , the Q ratio is output and a signal e is obtained. The signal e is determined by the mechanical positional relationship between the Hall element 51, which is the input signal source of the first signal generator 70, and the frequency generator of the second signal generator 80, and is generated once every rotation of the rotor. Since it is a signal, it becomes a signal indicating the mechanical origin (rotational phase reference) of the rotating body.

As described above, according to this embodiment, the relationship between the number N of pulse signals per rotation of the first signal generating means 7 and the second signal generating means 8 and M is expressed as follows: M==AXN+1 (A= 1.N=4), the rotational phase reference signal is obtained without increasing the number of parts, man-hours, or cost.

Next, other embodiments of the present invention will be described with reference to the drawings.

FIG. 4 is a block configuration diagram of a brushless DC motor according to an embodiment of the present invention, FIG. 5 is a specific configuration diagram of a rotational phase reference signal generation circuit, and FIG. 6 is a waveform diagram of main signals. In FIG. 4, the components other than 8C and 9Bll are the same as the configuration of the embodiment shown in FIG. 1, and therefore their explanation will be omitted. 8C is a six-pole magnetized permanent magnet placed on the rotating shaft 1A, 9
Reference numeral B designates a rotational phase reference signal generating circuit which outputs one pulse signal for each rotation of the rotor based on the outputs of the first j signal generating means 7 and the second signal generating means 8.

Next, its operation will be explained. First, the drive circuit e supplies a constant voltage vH to the position signal generator 60 Hall element 61°E52.53, and the three-phase drive coil 2, 3
, 4'f: Excite. Therefore, the permanent magnet 1B rotates.

As the permanent magnet 1B rotates, a back electromotive force is generated in the three-phase drive coils 2, 3.4, respectively. The back electromotive force of the drive coil 2 (signal f in FIG. 6) is input to the positive phase input terminal of the comparator 71 of the first signal generating means 7, and the three-phase Il'
1, the voltage v of the DC voltage source 10 that supplies power to the moving coil
By inputting M to the negative phase input terminal, 1 of the rotor
Four (N=4) pulse signals (signal q in Fig. 6) per rotation.
)&obtain. Further, the second signal generating means 8 includes a permanent magnet 8
All magnetic fluxes of C are detected, 3 pieces per rotation of the rotor (M=3)
A pulse signal (signal h in FIG. 3) is output. This signal is also a signal that controls the rotational speed of the rotor.

Here, the phase relationship between the output (signal q) of the first signal generating means 17 and the output (signal h) of the second signal generating means 17 is not shown in FIG. 6. It is a specific block diagram of generation circuit 9B. A signal q is sent to the D terminal of the D-type flip-flop 93, a signal is sent to the CK terminal, and a signal i is obtained as a Q output by connecting the ground point to the S and R terminals.

Note that the broken line indicates that the rising edge of the signal is 'Hi' of the signal q.
In the case where it occurs at the time of gh “Level”, the solid line is “’Low”
``This is the case at level.

A signal i is applied to the CK terminal of the D-type flip-flop 94.

Circuit power source 'Tonta■' to D terminal. c, Earth point at S terminal.

By applying an inverted signal (signal) of signal q to the R terminal, signal k is obtained as the O output. This signal is determined by the mechanical positional relationship between the drive coil 2, which is the input signal source of the first signal generation means 7, and the frequency generator of the second signal generation means 8, as in the previous embodiment, and is determined by the mechanical positional relationship of the frequency generator of the second signal generation means 8. 1 for every rotation of
Since this signal is generated individually, it becomes a signal indicating the mechanical origin (rotational phase reference) of the rotating body.

As described above, according to this embodiment, the relationship between the number N of pulse signals per rotation of the rotor of the first signal generating means 7 and the second signal generating means 8 and M is expressed as follows: N==I3XM+1 (N =4.B=1), the rotational phase reference signal is obtained without increasing the number of parts, man-hours, or cost.

In the above embodiment, if M:>H, M=AxN±1 (pieces); if M<H, N=BxM±1 (pieces) (However, M, N, A, and B are 1 In the relational expression (natural numbers above), A=B=1. Although N=4, the configuration is not limited to this, and any first signal generating means and second signal generating means may be used as long as they generate a signal that satisfies the above relational expression.

For example, when M>N, N=4. A: If it is 2, then M
-s±1, and if N)M, then N=4゜13=1
Then, M=3. Therefore, the first signal generating means and the second signal generating means may be configured so that N and M are obtained in each case.

Further, the present invention is not limited to a motor having a three-phase drive coil, but can also be configured to a motor having a plurality of phases of drive coils.

Effects of the Invention As is clear from the above explanation, the brushless DC motor of the present invention has a relationship between the number of output pulses N and M per rotation of the rotor of the first signal generating means and the second signal generating means. , If M>N, M=AxN±1 (pieces) If M<N(7), N=BxM-11 (pieces) (however, M
, N, A, and B are natural numbers of 1 or more), one rotational phase reference signal is generated for each rotation of the rotor.

In particular, the input signal source of the first signal generating means is a position signal generator or a drive coil that is a component of a brushless DC motor, and the second signal generating means outputs a signal that satisfies the above relational expression, By configuring a speed detection means whose output controls the speed of the rotor, all rotational phase reference signals can be generated without increasing the number of parts, man-hours, and cost, and miniaturization becomes easy. Excellent effects can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a block configuration diagram showing an embodiment of the present invention, FIG. 2 is a specific configuration diagram of a rotational phase reference signal generation circuit in an embodiment of the present invention, and FIG. 4 is a block configuration diagram showing another embodiment of the present invention. FIG. 5 is a specific configuration diagram of a rotational phase reference signal generation circuit in another embodiment of the present invention. FIG. 6 is a diagram of main signal waveforms in FIGS. 4 and 5. 1A... Rotor, 1B... Permanent magnet for field, 2.3, 4... Drive coil, 6...
...Position signal generator, 6...Drive circuit, 7.
...First signal generating means, sA, sC...
・M-pole pair magnetized permanent magnet, sB... Second signal generating means, 9A, 9B...C ・Rotational phase reference signal generating circuit, 10... DC voltage source. Name of agent: Patent attorney Toshio Nakao and 1 other person □
, 7th Figure 2 Figure 3/1.1 Figure 4

Claims (4)

[Claims] (1) A multi-pole magnetized permanent magnet attached to the rotor, a multi-phase drive coil arranged on the stator, and a position that generates a multi-phase position signal corresponding to the rotational position of the rotor. a signal generator, a drive circuit that sequentially excites the drive coils of the plurality of phases in response to the position signals of the plurality of phases, and a first signal generator that generates N pulse signals for each rotation of the rotor. a second signal generating means for generating M pulse signals for each rotation of the rotor; It is equipped with a rotational phase reference signal generation circuit that generates one pulse signal every time, and the relationship between N and M is expressed as
(In the case of N(7), N=BXM±1 (pieces) (However, C,
B, N, and M are natural numbers of 1 or more). (2) The first signal generating means is configured to generate N pulse signals for each rotation of the rotor from the output of the position signal generator. 1
Brushless DC motors listed in ). (3) The signal generation means at end 1 generates N pulse signals for each rotation of the rotor by processing the back electromotive force generated in the drive coils of multiple phases as the rotor rotates. A brushless DC motor according to claim 1, characterized in that the brushless DC motor is configured to do so. (4) The second signal generating means is composed of a speed detecting means for controlling the rotational speed of the rotor, and is configured to generate M pulse signals for each rotation of the rotor.