JPS62152361A - Brushless motor - Google Patents

Abstract

PURPOSE:To facilitate the magnetization of a permanent magnet used for a rotor and simple winding to reduce the cost, by appropriately setting the pole width and the dimension of the pole base of each magnetic pole of a stator. CONSTITUTION:A rotor 1 is provided with a cylindrical permanent magnet 2 magnetized with different poles alternately at equal intervals in the circumferential direction, a cup-formed yoke 3, and a rotary shaft 4; and the supply direction of the current in windings 11 arranged in a stator 5 is changed by the output of a magnetism-sensitive element 12. So far as the respective magnetic poles 6a, 6b of the stator 5 are concerned, an electrical angle for the magnetic pole surface width is arranged to be almost 90 degrees, and the width of the magnetic pole base is arranged to be sufficiently smaller than the magnetic pole surface width, and an electrical angle on the side of shorter distance between the magnetic poles is arranged to be almost 140 degrees, and the length from the center to the magnetic pole surface is formed to have a dimensional relation.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field 1] The present invention relates to a brushless motor using a magnetically sensitive element such as a Hall element.

[Background Art] This type of brushless motor combines a 2-pole or 4-pole stator with a 2-pole, 4-pole, or 4-pole, 8-pole permanent magnet rotor, and has a reluctance torque and a cycle twice that of the stator. The one that generates a current torque and synthesizes the current torque such that the peak value and the zero point of the reluctance torque coincide to always obtain a rotational torque in one direction is a temporary one. In this case, the formation of the magnetic poles of the permanent magnet rotor is complicated.

Therefore, the applicant of the present application, who is researching this type of brushless electric motor, has filed the patent application No. 59-177016. Special application 1986-199
917, etc., as shown in Fig. 6, the permanent magnet A of the rotor
is simply made into a cylindrical shape in which different poles are magnetized alternately at equal intervals in the circumferential direction, and the stator is made by changing the valley width of the pair of magnetic poles B and C, and by making a difference in the opening angle of adjacent magnetic poles, The structure of the rotor and stator with permanent magnets has been simplified. D is a Hall element.

However, when trying to further downsize and reduce the cost of electric motors, winding work becomes complicated because multiple windings do not have the same shape due to the shape of the magnetic poles of the stator, and the magnetic pole surface on the side with a smaller spacing between the magnetic poles Since the ends are close together, there is a risk of winding loss and breakage during the winding process.

[Object of the Invention] The present invention has been made in view of the above-mentioned reasons, and its purpose is to simplify the magnetization of permanent magnets used in the rotor while simplifying the winding. The purpose of the present invention is to provide a brushless electric motor that can reduce costs.

[Disclosure of the Invention] The brushless electric motor of the present invention comprises a rotor, a stator, a winding, and a current direction of the winding, each having a cylindrical permanent magnet in which different poles are alternately magnetized at equal intervals in the circumferential direction. In a brushless electric motor comprising a magnetically sensitive element for switching, each magnetic pole of the stator has the same dimensions with a magnetic pole surface width of approximately 90 degrees in electrical angle, a magnetic pole base sufficiently narrower than the magnetic pole surface width, and a distance between these magnetic poles. It is characterized in that the side with the smaller distance is approximately 140 electrical degrees, and the length from the center to the magnetic pole face has a size relationship, thereby achieving the above object.

(Example) An example of the present invention will be described below based on FIGS. 1 to 5.

Reference numeral 1 denotes a rotor having a cylindrical permanent magnet 2, which is constructed by fixing the permanent magnet 2 to the inner peripheral wall of a cup-shaped yoke 3 and fixing a rotating shaft 4 to the center of the bottom. The permanent magnet 2 has different poles (N pole, S pole) alternately magnetized at equal intervals in the circumferential direction. When developed in the circumferential direction of the permanent magnet 2, this magnetized state forms a sinusoidal waveform with a peak value at the center as shown in FIG. Or it is possible to make it more than that.

Reference numeral 5 denotes a stator made of a laminated iron core, which has magnetic poles 6 (in this embodiment, the first magnetic pole 6) equal to the number of poles of the rotor 1 (permanent magnet 2).
a, ° second magnetic pole 6b) and its magnetic pole surface 5c
, 5d face the permanent magnet 2 in the radial direction. 1st
．． The width of the second magnetic poles 5a, 5b is approximately 90 degrees in electrical angle, and the width of the magnetic pole bases 6e, 6f is the same, sufficiently narrower than the magnetic pole surface width, and the spacing between these magnetic poles is The smaller side is approximately 140 electrical degrees. Furthermore, the length from the center to the magnetic pole face 6C is R1, and the length from the center to the magnetic pole face 6C is R1.
If the length up to d is R2, then the size relationship is R1<R2, that is, the gap between the permanent magnet 2 and each magnetic pole face 5c, 5d is formed to have a size relationship. Therefore, the first
．． When the second magnetic poles 6a, 6b are not polarized, the rotor 1 is stopped so that the center of any one of the permanent magnets 2 and the center of the second magnetic pole 6b coincide with each other.

This stator 5 is fixed to the outer periphery of a cylindrical support 9 fixed to the main casing 8 . Further, a bearing 10 is mounted on the inner periphery of the cylindrical support body 9, and the rotating shaft 4 is rotatably supported by the bearing 10.

Reference numeral 11 denotes a two-phase winding that is wound with a series bifilar winding around each magnetic pole base 5e, 5f of the stator 5, and when a current is passed through it, each magnetic pole 5a, 5b has N, S polarity or S, N polarity. Give. Naturally, when the current direction is switched, the polarity applied to each magnetic pole 5a, 5b is switched.

Reference numeral 12 denotes a magnetic sensing element consisting of a Hall element attached to the stator 5, which detects one of the polarities (in this example, the N pole) of the permanent magnet 2 of the rotor 1, and its output is used in a general current switching circuit. is input to switch the current direction of the winding 11.

The current switching circuit is, for example, as shown in Fig. 5, and when the magnetic sensing element 12 detects the N pole, it turns on the transistor Q3, turns on the transistor Q1, and turns off the transistor Q2, and when it detects the S pole, it turns off the transistor Q3. to turn off transistor Ql.

Transistor Q2 is turned on to switch the currents in windings tta and llb.

(Operation) FIG. 4(a) shows a stable stopped state in which no current flows through the winding 11. When current is passed through the winding 11 in this state, the first magnetic pole 6a is given an N pole, and the second V71 pole 6b is given an S pole. Therefore, the N pole of the permanent magnet 2 receives a repulsive force from the N pole of the first magnetic pole 6a and an attractive force from the S pole of the second Vi1 pole 6b, causing the rotor 1 to rotate in the direction indicated by the arrow. When the permanent magnet 2 rotates to the state shown in (b), the S pole of the permanent magnet 2 also receives a repulsive force from the S pole of the second magnetic pole 6b and an attractive force from the N pole of the first magnetic pole 6a.
It reaches the position (d) rotated by 180° via C).

In this state, the magnetic sensing element 12 detects the N pole and the winding 11
Therefore, the current direction of the first . Second magnetic pole 6a.

The polarity applied to 6b is switched, and this is repeated thereafter, so that the rotor 1 continues to rotate.

Although this embodiment has been described with the rotor disposed outside the stator, the rotor may be disposed inside the stator.

[Effects of the Invention] The brushless electric motor of the present invention has the same dimensions in which each of the magnetic poles of the stator has a magnetic pole surface width of approximately 90 degrees in electrical angle, the magnetic pole base is sufficiently narrower than the magnetic pole surface width, and the spacing between these magnetic poles is The smaller side of the magnetic pole is approximately 140 degrees in electrical angle, and the length from the center to the magnetic pole face has a size relationship, which not only enables self-starting in one direction, but also improves the magnetization of the permanent magnet. Although it is simple, the winding wire wound around each magnetic pole has the same shape, making the winding work easier, and the distance between the ends of the magnetic pole faces on the side where the spacing between the magnetic poles is smaller is also wider than that of the conventional type. In the winding process, wire breakage is less likely to occur due to winding loss, and winding can be simplified and costs can be reduced.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing one embodiment of the present invention, FIG. 2 is a vertical cross-sectional view thereof, FIG. 3 is a characteristic diagram showing the magnetized state of the rotor, and FIG.
)(b)(c)(d) are operation explanatory diagrams, FIG. 5 is a circuit diagram of a general current switching circuit, and FIG. 6 is a cross-sectional view showing a conventional example. ■-rotor, 2.-permanent magnet, 3.-cup-shaped yoke,
4-rotating shaft, 5-stator, 6--magnetic pole, 9--cylindrical support, 11--winding wire, 12--magnetic sensing element. Patent applicant: Matsushita Electric Works Co., Ltd. Patent attorney: Takemitsu Sanko (and 2 others) Figure 1 Figure 2 Figure 3 Figure 4 (C) (d) Figure 5 Figure 6

Claims (1)

[Claims] (1) A rotor that has a cylindrical permanent magnet in which different poles are alternately magnetized at equal intervals in the circumferential direction, and a rotor that has magnetic poles equal to the number of poles of the rotor and whose magnetic pole surface is the permanent magnet of the rotor. A stator facing the magnet in the radial direction, a winding wound around each magnetic pole of the stator, and a winding attached to the stator that detects the polarity of the rotor and switches the current direction of the winding. In a brushless motor comprising a magnetically sensitive element, each magnetic pole of the stator is
The magnetic pole surface width is approximately 90 degrees in electrical angle, the magnetic pole base is sufficiently narrower than the magnetic pole surface width, and the side with the smaller spacing between these magnetic poles is approximately 140 degrees in electrical angle, and the length from the center to the magnetic pole surface is A brushless electric motor characterized in that the brushless motor is formed to have a size relationship.