JPH06276720A - Dc brushless motor - Google Patents

Abstract

PURPOSE:To facilitate the assembling of a motor and to suppress the lowering of its characteristics. CONSTITUTION:A Hall element 2w' is arranged at the center position of adjoining arbitrary two Hall elements 2u and 2v, out of three Hall element 2u, 2v, and 2w' arranged into an arc at equal angles for detecting the position of a magnet rotor 1 by their outputs, and the output of the Hall element 2w' arranged at this center position is reversed, and taken out. An the position of the rotor 1 is detected by the outputs of this Hall element 2w' arranged in the center position and other adjoining two Hall elements 2u and 2v.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a DC brushless motor for detecting a rotor position by using a Hall element.

[0002]

2. Description of the Related Art In a conventional DC brushless motor, as shown in FIG. 4, the positions of, for example, 4-pole magnet rotors 1 (hereinafter referred to as "rotors") are arranged on the outer periphery of the rotor 1 in an arc shape at equal angles. Detected by the outputs of the three Hall elements, that is, the U-phase Hall element 2u, the V-phase Hall element 2v, and the W-phase Hall element 2w, the windings 4 of the stator 3 are sequentially excited according to the detected position of the rotor 1. Rotor 1
I am trying to rotate.

Here, these three Hall elements 2u,
The 2v and 2w are turned on when facing the N pole, turned off when facing the S pole, and are turned on and off every time the rotor 1 rotates 90 °. And
When each of these Hall elements 2u, 2v, 2w is turned on, a current flows through the corresponding U-phase, V-phase and W-phase windings 4, and each winding 4 is excited.

In this DC brushless motor, the stator 3 is rotated by 60 ° in order to rotate the rotor 1 efficiently.
The winding 4 to be excited is sequentially changed with each rotation. Then, these Hall elements 2v, 2w, 2u are detected so as to detect that the stator 3 has rotated by 60 °.
As shown in the figure, the rotors 1 are arranged in an arc shape while being shifted by 60 ° while facing the rotor 1.

[0005]

However, in such a conventional DC brushless motor, since the hall elements are arranged so as to be shifted by 60 ° in this way, the mounting angle of the three hall elements is 120 °. (= 60 ° × 2)
Therefore, the substrate on which these Hall elements are arranged becomes large.

It is troublesome to incorporate such a large substrate into the motor so as to face the magnetic poles of the rotor, and since the mounting position of the substrate is located in the air passage of the motor, the substrate is the air passage. There is a problem in that a part of the motor is blocked and the characteristics of the motor such as the intake of outside air are deteriorated.

It is an object of the present invention to provide a DC brushless motor which is easy to assemble and which can suppress deterioration of motor characteristics.

[0008]

SUMMARY OF THE INVENTION According to the present invention, a rotor is sequentially excited by exciting a winding in accordance with the rotor position detected by outputs of three Hall elements arranged in an arc shape at an equal angle on the outer circumference of the rotor. In a DC brushless motor that rotates
Another hall element is arranged at the center position of any two adjacent hall elements of the three hall elements, and the output from the hall element arranged at this center position is reversed and taken out. It was done.

[0009]

The other Hall elements are arranged at the center position of any two adjacent Hall elements among the three Hall elements which are arranged in an arc shape at equal angles and whose output detects the rotor position. The output from the Hall element arranged at this center position can be reversed and taken out. Then, the position of the rotor can be detected by the outputs of the Hall element arranged at the center position and the other two adjacent Hall elements.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a partial sectional view showing the structure of a DC brushless motor according to an embodiment of the present invention. In the figure, the same reference numerals as those in FIG. 4 indicate the same or corresponding parts.

In the figure, 5 is a DC brushless motor main body (hereinafter referred to as "main body"), 6 is a fan for rotating by the rotor 1 to suck outside air, and 6a is a cooling fan cover. Reference numeral 7 denotes a diffuser that forms a ventilation path. The diffuser 7 is attached to a frame 7a, and a substrate 8 is provided on the opposite side of the frame 7a.
Is attached.

Here, as shown in FIG. 2, on this substrate 8, any two adjacent Hall elements, in the present embodiment, the U-phase Hall element 2u and the V-phase Hall element 2v are placed at the other center positions. A W-phase hall element 2w 'is arranged.

As a result, the angles formed by the W-phase Hall element 2w ', the U-phase Hall element 2u and the V-phase Hall element 2v are each 30 °, and the three Hall elements 2u, 2 are arranged.
Since the mounting angle of v, 2w ′ is 60 ° (= 30 ° × 2), the mounting angle becomes half of the conventional one, and the substrate 8 can be downsized.

The W-phase Hall element 2w 'is mounted in the opposite direction so that the output is reversed, for example, the back surface is used. Therefore, when the N-pole of the rotor 1 faces the W-phase Hall element 2w ′ attached in this way, the output of the W-phase Hall element 2w ′ is reversed and the same as when it faces the S-pole. It is supposed to be off.

In the DC brushless motor having the above structure, when the rotor 1 rotates, the U-phase Hall element 2u, the W-phase Hall element 2w 'and the V-phase Hall element 2v are shown in FIGS. The signals as shown in b) and (c) are output, respectively.

Since the output of the W-phase Hall element 2w 'shown in FIG. 3B is mounted in the opposite direction, the W-phase Hall element 2w' shown in FIG. 3D for reference.
The output is in the opposite phase when the is installed face up.

Further, the output of the W-phase Hall element 2w 'is the same as the output of the W-phase Hall element 2w placed in the conventional position as shown in FIG. Will be the same.

In this way, the W-phase hall element 2w 'is placed at the center position between the U-phase hall element 2u and the V-phase hall element 2v.
In addition, the position of the rotor 1 can be detected by mounting so that the back surface is used. Further, by setting the mounting angle of the three Hall elements 2u, 2v, 2w 'to 60 °, the substrate 8 can be downsized and the degree to which the substrate 8 blocks the ventilation path can be reduced.

When the back surface of the W-phase Hall element 2w 'is used in this way, the sensitivity of the W-phase Hall element 2w' is slightly lowered, but this is because, for example, the W-phase Hall element 2w 'is brought closer to the rotor 1. It is possible to make a correction by finely adjusting the mounting position or adjusting the mounting angle.

By the way, in the above description, W
Although the case where the back surface is used to invert and take out the output of the phase Hall element 2w 'has been described, the present invention is not limited to this, and the output of the W phase Hall element 2w' can be electrically processed. The output can be reversed and taken out.

Even in this case, since the electrical processing is performed, the processing time is longer than in the conventional case. However, this is because the mounting position of the W-phase Hall element 2w 'is laterally deviated and the timing of starting the processing is finely adjusted. It is possible to correct by doing.

[0023]

As described above, according to the present invention, the substrate can be miniaturized by arranging another Hall element at the center position of any two adjacent Hall elements, so that the assembly is simplified, and It is possible to reduce the degree to which the ventilation path of the substrate is blocked, and it is possible to suppress deterioration of motor characteristics.

[Brief description of drawings]

FIG. 1 is a partial sectional view of a main part of a DC brushless motor according to an embodiment of the present invention.

FIG. 2 is an enlarged plan sectional view of an essential part of the DC brushless motor.

FIG. 3 is a diagram showing the output of each Hall element of the DC brushless motor.

FIG. 4 is an enlarged plan sectional view of an essential part of a conventional DC brushless motor.

[Explanation of symbols]

 1 Magnet rotor 2 Hall element 4 Winding 5 DC brushless motor body 8 Board

Claims (1)

[Claims] 1. A DC which sequentially excites windings to rotate a rotor according to rotor positions detected by outputs of three Hall elements arranged in an arc shape at an equal angle on the outer circumference of the rotor.
In the brushless motor, another hall element is arranged at the center position of any two adjacent hall elements among the three hall elements, and the output from the hall element arranged at this center position is reversed. A DC brushless motor characterized by being taken out by taking out.