JPS58123355A - Synchronous motor - Google Patents

Abstract

PURPOSE:To enhance the responding speed of a synchronous motor by continuously varying the thickness of permanent magnets provided on a rotor to form the distribution of magnetic flux density between a stator and the magnet in a sinusoidal state, thereby reducing the inductance of a stator coil. CONSTITUTION:A coil (not shown) is wound in grooves (not shown) formed on the inner periphery of a stator 1, which electric iron plates are laminated, and at least two permanent magnets 3-1-3-4 are provided on the outer periphery surface of a yoke 2 (which includes a shaft) provided at the center of the stator 1. Then, the thicknesses of the magnet 3-1-3-4 are continuously varied as prescribed so that the gap lengths between the stator 1 and the respective magnets 3-1-3-4 become minimum at the centers of the magnets 3-1-3-4 and maximum at the periphery, and the distribution of the magnetic flux of the air gaps between the stator 1 and the magnets 3-1-3-4 is formed in sinusoidal wave state.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a synchronous motor having field magnets (permanent magnets) arranged radially; Generally, a synchronous motor has a magnetic starter, in which electromagnetic iron is laminated and wound, and a magnetic starter is used. The opening provided in the center of the stator is tX@. For example, with a four-way synchronous motor,
For example, in that rotor.

Four field magnets (permanent magnets) arranged at equal intervals along the inner peripheral surface of the stator are fixed to the m-iron.

In such a synchronous motor, it is possible to make the magnetic flux vM degree distribution in the dark air gap between the stator and rotor sinusoidal in order to obtain uniform torque characteristics and other controllability. 0 In a conventional synchronous motor, the air gap length t between the stator and rotor is continuously increased by fixing a magnetic material, for example iron, of varying thickness to the outer circumference of a field stone with a constant thickness. change, thereby
The magnetic flux 1#& distribution in the air gap was made sinusoidal between the walls.

However, in the above-mentioned conventional type, the magnetic resistance of the iron of the magnetic material is smaller than that of the boundary stone, and the inductance of the winding of the stator becomes large.
There is a problem in that the response speed of the synchronous motor decreases. In particular, this becomes a serious problem when high response speed is required, such as with a synchronous servo motor.

The purpose of the invention was to reduce the inductance of the stator winding to 1 and reduce the inductance of the stator winding to 1gE based on the idea of continuously changing the thickness of the field magnetic field with high resistance and providing it directly under the stator winding. The purpose is to increase the response speed of the synchronous motor and solve all the problems in the conventional type of motor.

An actual tN1 example of the present invention will be explained below with reference to nine drawings.

FIG. 1 is a sectional view of a four-pole synchronous motor as an embodiment of the present invention. In Fig. 1, l is a stator on which electromagnetic iron plates are laminated, and #1 (not shown) in the axial direction of the inner cylinder is equipped with a winding (not shown). .

Four field magnets (permanent magnets) 3-1 to 3-4 are provided on the outer peripheral surface of the joint 2 (including the shaft) at the center of the stator 1, that is, along the inner periphery of the stator 1. ing.

In order to simplify the magnet shape, the stator 1 and each field magnet 3 are
The air gap length between -1 to 3-4 is set to be minimum at the center and maximum at the periphery.

As a result, the magnetic flux density distribution in the air gap () is made into a sine wave.

As shown in FIG. 1, according to the present invention, a field magnet 3-1
The thickness of ~3-4 is continuously changed, and this stator 1
The field magnets 3-1~
Since the magnetic resistance of 3-4 is large, the inductance of the stator 1 is small.

Next, using the figures 2 to 4, the stator 1 and the field magnet 3 are
Determination of the air gap length between "-1 and -" will be explained.

Figure 2 is an enlarged version of Figure 1 by @, and the field magnet 3-1
It shows the vicinity of . In fig.

L(71,LQ'lr...+LQ6+...,L91
1 is the air gap length set at equal intervals, Lmx
+ Zr2) B2 r...+ Lma l・"l
Lmll is air gap-*Lg 1. Lg 21
...eLQ@t...p It is the thickness of the field magnet 3-1 corresponding to Lgl 1. Air gap length LQ l +
Magnetic flux density B1 + in the air gap where L(l g +...pLg6t...+LQ11 is set
B2 r..., B6. ....

Bll is distributed in a sinusoidal manner as shown in FIG. Such air 7'f-r tube length and field magnet: 1
The thickness of 111 3-1 is then determined using the Bosu permeance coefficient P.

LgA...? However, L, the air gap length of the knee magnetic circuit 9m knee magnetic (gIM field magnet thickness A, knee magnetic tgJM air gap cross-sectional area A-; -m field a of the knee magnetic circuit cross-sectional area of the magnet f 2 Shuto leakage coefficient r: Contact layer coefficient In this case, in the magnetic circuit formed near each air feed f, Ag = AWL, f / r 1. Therefore, the permeance coefficient P is compared to ,,,
/L.

will be determined by. On the other hand, the permeance coefficient P is expressed by the magnetic flux density B1m field strength H.

Therefore, as shown in FIG. 4, each magnetic flux density B1 in FIG.
182. ..., B1, the permeance coefficient value p1. p2. ..., P□1 is found. 2°4 is the B-H characteristic curve edge determined by the material of the field magnet 3-1. As a result, the air gap length was 1°9g2.・
...e LQ @ r...l LQ 11 and thickness of field magnet 3-1 8 z-0l Lm2 t...'
Ltyts'...# Lm, 1 will be determined uniformly.

In this way, the length of the dark air gap between the stator 1 and the field stone 3-1 can be continuously changed, and the magnetic flux density distribution in the air gap can be made into a positive V:vertical shape.

Incidentally, FIG. 3 shows the magnetic flux density distribution of 1<'II inclination 0 to K). Further, in the second embodiment described above, a four-pole synchronous motor is shown, but it goes without saying that the present invention can be applied to other two-pole or more synchronous motors.

As explained above, according to the present invention, while maintaining a sinusoidal magnetic flux density distribution, the field magnet itself with high magnetic resistance is provided directly below the stator winding, so the inductance of the stator winding can be reduced. I can do it.

Therefore, the response speed of the synchronous motor can be increased.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a four-wood synchronous motor as an embodiment of the invention, and FIG. 2 is a partially enlarged view of FIG. 1. FIGS. 3 and 4 show the air gap L1 in FIG. 2. . L, , -..., L, 1□ is the next graph that determines Ol: stator. 2: Yuino ・ 3-1 to 3-4: Field magnet (water-immersed magnet) Ot#ken application applicant through FANUC Co., Ltd. Patent application agent 9P patent attorney Akira Yoiki Patent attorney Kazuyuki Nishidate Patent attorney Akira Yamaguchi

Claims (1)

[Claims] 1. The stator with PM and Jd of the cough stator
In a synchronous motor comprising a rotor having at least two permanent magnets arranged at equal intervals along the i1 plane, a. A synchronous motor 0 characterized in that the magnetic flux density distribution in the air gap between each of the permanent magnets is sinusoidal.