JPH02101989A - Brushless motor - Google Patents

Abstract

PURPOSE:To enable smooth starting by providing a pulse generator for feeding a pulse signal to a stator coil when a brushless motor is started and a mode switching circuit section for stopping the input of the pulse signal to the stator coil and switching to normal rotation of motor through a rotor position detector. CONSTITUTION:A brushless motor comprises a pulse generator 5 for inputting a pulse signal to a stator coil 4, a counter 6 for counting the pulse signals provided from the pulse generator 5, and a mode switching circuit 7 for stopping the input of the pulse signal to the stator coil 4 and switching to normal rotation through a rotor position detector 5. A rotor magnet 1 is shifted from the dead point by means of the pulse signal provided from the pulse generator 5, and switching is made to normal rotation through the rotor position detector 3 under the state. By such an arrangement, the motor is started smoothly and smooth rotation is continued thereafter.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a brushless morph, and particularly to a DCC brushless morph with a two-phase unipolar drive system.

[Conventional technology]

Generally, a two-phase unipolar drive is often used as a fan motor.

For this type of motor, in order to eliminate dead points at startup and ensure smooth startup, the zero point of the torque waveform at startup and the stable point (zero point) of detent torque
(For example, a method in which the magnetization of the magnet is unbalanced, a method in which the stator stack shape is unbalanced, etc.) was used.

[Problem to be solved by the invention]

The methods described in the conventional technology have problems such as vibration (electromagnetic vibration) and noise due to unbalance, and furthermore, they have the disadvantage of being difficult to manufacture and high cost.

Therefore, with the present invention, it is possible to start up smoothly,
Moreover, it is an object of the present invention to provide a brushless morph that has a simple structure and can be manufactured at low cost.

[Means to solve the problem]

In order to achieve the above object, the brushless morph in the present invention includes a pulse generator for inputting a pulse signal to the stator coil at the time of startup; and a rotor position for switching energization to the stator coil for normal motor rotation With a detector;
a counter that counts pulse signals from the pulse generator and detects that one pulse signal is input to each phase of the stator coil; A mode switching circuit section that stops inputting a pulse signal to the stator coil and switches the motor to normal rotation based on the rotor position detector.

[Effect]

When the motor starts, the rotor magnet stops at the dead point position, and in this state, if a pulse signal is input from the pulse generator to the stator coil, each phase will be energized at least once. Thus, a state is created in which the stator poles facing the rotor magnet poles are of the same polarity. At this time, the rotor magnet deviates from the dead point, and immediately after receiving the detection signal from the counter, the mode switching circuit stops inputting the pulse signal to the stator coil, and the rotor position The motor is switched to normal rotation by the detector. Therefore, the motor is driven to rotate continuously.

〔Example〕

Examples will be described below with reference to the drawings.

FIG. 4 shows a simplified plan view of a brushless morph according to the present invention, and this motor is a two-phase unipolar drive type DC brushless motor, with a four-pole rotor magnet 1,
a stator 2 fitted inside the rotor magnet 1;
The motor rotates by switching the energization to the stator coil 4 in response to a signal from a rotor position detector 3 disposed close to the rotor magnet l.

Therefore, in this motor, the torque generated by excitation of each phase has the waveforms ■ and waveforms ■ in Figure 3,
In addition, in the same figure, the waveform ■ indicates detent torque.
In other words, the stable points of the rotor are point a, point b, and
There are four points, the 0 point and the d point, which are the so-called dead points of the rotor magnet l. When the rotor magnet 1 is in a stopped state, the rotor magnet 1 is at a dead point, and although the stator coil 4 is energized, the torque is zero, so it does not start.

However, when the negative phase is excited, the positional relationship will be as shown in FIG. 4 I or FIG. 4 ■. In other words, in the state shown in FIG.
Holding the inquiry stopped state, in the state shown in Figure 4 ■,
The stator poles facing the poles of the rotor magnet l are of the same polarity and repel, and the rotor magnet l rotates 90" in the circumferential direction and stops. In addition, when the other phase is excited, the opposite occurs as shown in FIG. If it is in the state shown in Figure 4, the state will be as shown in Figure 4. If it is in the state shown in Figure 4, it will be in the state shown in Figure 4.゛Rotates and stops. Therefore, if each phase is excited once,
The rotor magnet 1 will rotate at least 90 degrees, and if the rotor position detector 3 is energized during this rotation, continuous rotation will be obtained. In addition,
In FIG. 4, N indicates a north pole, and S indicates a south pole.

Therefore, in the present invention, at least the rotor magnet l-1 is moved in the circumferential direction from the stopped state of the rotor magnet l as described above, and during the movement, the rotor position detector 3 is used to excite the rotor magnet l. .

That is, as shown in FIGS. 1 and 2, this brushless morph includes a pulse generator 5 for inputting pulse signals to the stator coil 4 at startup, and a counter for counting the pulse signals of the pulse generator 5. 6, and a mode switching circuit section 7 that stops the input of pulse signals to the stator coil 4 and switches the rotor position detector 5 to normal rotation of the motor.

Specifically, in this brushless morph drive circuit, a pulse signal generated from a pulse generator 5 is input to the stator coil 4 via a counter 6, a mode switching circuit section 7, and an amplifier 8. Therefore, if a pulse signal is input to the stator coil 4, the stator coil 4 will be excited, so if a pulse signal is input to each phase of the stator coil 4 once, the voltage of either phase will be excited. When inputting, the fourth
The state shown in Figure H can be achieved. The counter 6 detects that one pulse signal is input to each phase of the stator coil 4, and inputs the detected signal to the mode switching circuit section 7. teeth,
The rotor magnet 1 rotates in the circumferential direction and deviates from the dead point. And in this deviated state,
Since the mode switching circuit section 7 switches the motor to normal rotation, the rotor position detector 3 detects the rotor magnet 1.
By detecting the position of stator coil 4, the current supply to stator coil 4 can be switched, and continuous rotation of the motor can be achieved. Note that the mode switching circuit section 7 is a NAND circuit 10.1.
1, a transistor 12, and a resistor 13.14, and an additional 8 consists of a transistor 15.16 and a resistor 17.
18, and in Figures 1 and 2, 9
is an amplifier provided between the rotor position detector 3 and the mode switching circuit section 7.

Therefore, FIG. 5 shows a pulse signal and an input signal of the amplifier 8 that drives the stator coil 4. In the figure, mode 1 indicates a state in which a pulse signal is input to the stator coil 4, and mode 2 and 1 shows a state in which energization is switched to the stator coil 4 for normal rotation of the motor. In addition, f and ■ in FIG. 5 indicate signals output from the counter 6, and ■ and ■ in FIG. 5 change to signals of opposite polarity when the pulse signal is switched to the signal from the rotor position detector 3. FIG. 5V and (2) show the case where the signal changes to the same polarity when the pulse signal is switched to the signal from the rotor position detector 3.

〔Effect of the invention〕

Since the present invention is configured as described above, it produces the effects described below.

The pulse signal from the pulse generator 5 causes the rotor magnet 1 to deviate from the dead point, and in this state the rotor position detector 3 switches the motor to normal rotation, so the motor starts smoothly. Once started, smooth continuous rotation can be obtained, electromagnetic vibrations are extremely small, and noise can be reduced. In addition, there is no need to make the magnetization of the magnet unbalanced or the shape of the stack stack unbalanced as in the past, and the structure is extremely simple, which has the advantage of being easy to manufacture and not requiring high costs. It turns out.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of an embodiment of a brushless motor according to the present invention, FIG. 2 is a block diagram thereof, and FIG. 3 is a torque waveform diagram.
FIG. 4 is a simplified plan view, and FIG. 5 is a waveform diagram. 3... Rotor position detector, 4... Stator coil,
5... Pulse generator, 6... Counter, 7... Mode switching circuit section.

Claims (1)

[Claims] 1. A pulse generator 5 for inputting a pulse signal to the stator coil 4 at startup, a rotor position detector 3 for switching energization to the stator coil 4 for normal rotation of the motor, and a pulse signal from the pulse generator 5. a counter 6 that counts and detects that one pulse signal is input to each phase of the stator coil 4; and a signal from the counter 6 that causes the pulse generator 5 to send the pulse signal to the stator coil 4; A brushless motor comprising: a mode switching circuit section 7 for stopping input of a pulse signal and switching to normal rotation of the motor by the rotor position detector 3.