KR20050006040A - A stator core of a permanent magnet motor and the permanent magnet motor - Google Patents

Abstract

PURPOSE: A stator core and a permanent magnet motor are provided to efficiently improve lowering of cogging torque without decreasing induction voltage generated during rotation by radially arranging teeth with respect to a rotating shaft. CONSTITUTION: A stator core comprises a plurality of teeth(5) radially arranged with respect to a rotating shaft. Each of the teeth has a head(5a) formed at the front end of each of the teeth. The plane of the head, opposed to a rotor permanent magnet(13), is constructed convexly toward the rotor permanent magnet. The length of the air gap formed between the head and the rotor permanent magnet is set such that the ratio between the length of the air gap at the center of the head and the length of the air gap at both ends of the head in a circumferential direction falls within the range of 1.4 to 2.4.

Description

Stator iron core and permanent magnet motor of permanent magnet motor {A STATOR CORE OF A PERMANENT MAGNET MOTOR AND THE PERMANENT MAGNET MOTOR}

The present invention relates to a stator iron core and a permanent magnet motor of a permanent magnet motor, in which a plurality of teeth are disposed radially with respect to a rotation axis to reduce cogging torque without lowering an induced voltage generated during rotation. will be.

As a conventional technique for the purpose of reducing the cogging torque without lowering the induced voltage generated during rotation of a stator core of a permanent magnet motor, it is disclosed, for example, in Japanese Patent Application Laid-Open No. 09-344646. There is something.

This technique is to form the shape of the surface on the side facing the rotor permanent magnet of the tooth head in an abduction type motor in an arc shape centering on the center of rotation of the rotor with respect to the center part in the circumferential direction, As it goes to the both ends of the circumferential direction from the center part of the circumferential direction, it is set as the shape which moves away from a rotor permanent magnet smoothly.

By the way, when the face shape of the tooth head is formed as described above, if both ends of the tooth head approach the rotor permanent magnet, that is, the gap between them becomes smaller, the effective magnetic flux acting on the rotor increases. The induced voltage increases, but on the one hand the cogging torque and torque ripple also increase. Further, if both ends of the tooth head are separated from the rotor permanent magnet, that is, the gap between them becomes larger, the cogging torque and torque ripple are smaller, but the effective magnetic flux is also smaller, so that the induced voltage is also reduced.

That is, there is a trade-off between securing the induced voltage level and suppressing cogging torque and torque ripple in how to set the gap length between the both ends of the tooth head and the rotor permanent magnet. Therefore, although the relationship should be set so that the relationship may be optimal about the said gap length, the said patent document does not have such a disclosure.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object thereof is to provide a stator core and a permanent magnet motor of a permanent magnet motor capable of more effectively reducing the cogging torque without lowering an induced voltage generated during rotation. It is in doing it.

The stator iron core of the permanent magnet motor according to claim 1 has a plurality of teeth disposed radially with respect to the rotation axis,

The convex shape of the side facing the rotor permanent magnet of the tooth head at the tip of the tooth is convex toward the permanent magnet side,

The gap length between the tooth head and the rotor permanent magnet is set so that the ratio of both ends to the center in the circumferential direction is in the range of 1.4 to 2.4.

That is, the inventors of the present invention simulated the generation state of the induced voltage and the cogging torque when the ratio of the pore length was changed. As a result, when the ratio of both ends with respect to the center of the circumferential direction was set to the range of 1.4-2.4, it turned out that the balance of both is in a suitable state.

In addition, as described in claim 2, the surface shape of the side of the tooth head facing the rotor permanent magnet is convex toward the permanent magnet side, and the ratio of the void length is set within the range of 1.6 to 2.2. As described in claim 3, it can be seen that when the ratio of the void length is set in the range of 1.8 to 2.0, the generation balance between the induced voltage and the cogging torque is further optimized.

The stator iron core of the permanent magnet motor according to claim 4 has a plurality of teeth disposed radially with respect to the rotation axis,

The face shape of the side of the tooth head opposite to the rotor permanent magnet of the tooth head is arc-shaped with the center in the circumferential direction centered on the center of rotation of the rotor, and both ends thereof make a tangent contacting both ends of the arc. At the same time,

The gap length between the tooth head and the rotor permanent magnet is set so that the ratio of both ends to the center in the circumferential direction is in the range of 1.6 to 2.6.

That is, in the face shape of the tooth head, when the both ends leading to the arc-shaped center portion form a tangent contacting each end of the arc, the change in the gap length from the center portion to the both ends becomes smoother. It is more advantageous to adjust the pore length.

Also in this case, as described in claim 5, the ratio of the void length is set in the range of 1.8 to 2.4, and further, as described in claim 6, the ratio of the void length is set in the range of 2.0 to 2.2. In this case, the generation balance between the induced voltage and the cogging torque becomes more optimal.

1 is a first embodiment when the present invention is applied to an abduction type permanent magnet motor, (a) is an enlarged view of the tooth head and the rotor permanent magnet portion, (b) is an air gap length ratio (G2 / G1) and a diagram showing the ratio between the induced voltage and the cogging torque generated when the permanent magnet motor rotates.

2 is an enlarged view of a tooth head portion;

3 is a plan view of a stator iron core;

4 is a longitudinal sectional view of a permanent magnet motor.

Fig. 5 is an equivalent view of Fig. 1 showing a second embodiment of the present invention.

Fig. 6 is an equivalent view of Fig. 3 showing the third embodiment in the case where the present invention is applied to an abduction type permanent magnet motor.

<Explanation of symbols for main parts of drawing>

1: permanent magnet motor

2: stator iron core

5: teeth

5a: tooth head

5b: central part

5c, 5d: end

13: rotor permanent magnet

15: teeth

15a: tooth head

16: stator iron core

17: tooth

17a: tooth head

18: rotor permanent magnet

20: permanent magnet motor

(First embodiment)

Hereinafter, a first embodiment in the case where the present invention is applied to an abduction type permanent magnet motor will be described with reference to FIGS. 1 to 4. First, FIG. 4 is a longitudinal cross-sectional view of the abduction type permanent magnet motor 1. In FIG. 4, the stator iron core 2 is formed by stacking a plurality of ring-shaped punched silicon steel sheets, and a circular hole 4 for mounting the bearing 3 is formed in the center portion thereof. 3, in this case, 12 teeth 5 are provided in the circumferential direction.

The armature windings 7 are wound around the teeth 5, and the tooth heads 5a at the tip end of the teeth 5 protrude radially outward from the armature windings 7. And the stator 8 is comprised by the stator iron core 2 and each armature winding 7.

On the other hand, the rotor 10 includes a rotating shaft 11 freely supported by the bearing 3, a rotor yoke 12 fixed to an upper end of the rotating shaft 11, and the rotor yoke. It consists of a cylindrical rotor permanent magnet 13 provided on the inner circumferential surface of the tube part 12a of (12), and this rotor permanent magnet 13 is the tooth head of the teeth 5 in the stator core 2. It is arrange | positioned so that it may oppose to 5a in radial direction through an air gap (gap).

Here, as shown in Fig. 1 (a) or Fig. 2, the surface shape of the side opposite to the rotor permanent magnet 13 in the tooth head 5a of the tooth 5 is 5b as the center portion. The radius centering on the rotation center O1 of the rotor 10 is formed in the arc shape of r1. Therefore, the air gap length G1 between the center part 5b of the tooth head 5a and the rotor permanent magnet 13 is the same in the circumferential direction.

And the surface shape of the rotor permanent magnet 13 side in the edge part 5c, 5d which extended to both sides of the center part 5b is formed so that it may be tangent with respect to the end point of the arc which forms the center part 5b. In addition, these are two-dimensional expressions of surface shapes, but in three-dimensional expression, since the surface shape of the center portion 5b forms a cylindrical surface, the surface shapes of the end portions 5c and 5d are relative to the cylindrical surface ends. It forms a tangent plane in direct contact with the axis.

In addition, as shown in FIG. 2, the circumferential arrangement ratios of the end portion 5c, the center portion 5b, and the end portion 5d are formed to be approximately 1: 2: 1. In this case, the surface shape of the side facing the rotor permanent magnet 13 in the tooth head 5a smoothly moves toward the both ends 5c and 5d at the central portion 5b, respectively. The air gap length between the tooth head 5a and the rotor permanent magnet 13 increases gradually toward the ends of each of the both ends 5c and 5d. And, at the left end of the end 5c and the right end of the end 5d, the air gap length G2 with respect to the rotor permanent magnet 13 becomes maximum, but the ratio of the air gap lengths G1 and G2 is 1: 2. It is set to be.

Fig. 1 (b) shows the ratio of the air gap length (G2 / G1) to the horizontal axis, and the ratio of the induced voltage and cogging torque generated when the permanent magnet motor 1 rotates to the vertical axis. That is, as described above, when both ends 5c and 5d of the tooth head 5a approach the rotor permanent magnet 13, the induced voltage increases, but on the other hand, the cogging torque and torque ripple also increase, and both ends When 5c and 5d move away from the rotor permanent magnet 13, cogging torque and torque ripple become small, but the induced voltage also becomes small.

Therefore, when the ratio (organic voltage) / (cogging torque) is changed as the index for making the cogging torque very small and the induced voltage very large, the (organic voltage) is changed. The change of) / (cogging torque) was calculated | required by simulation. As a result, when the ratio G2 / G1 becomes approximately "2",

It can be seen that (organic voltage) / (cogging torque) represents almost maximum.

According to the present embodiment as described above, the center portion 5b in the circumferential direction of the surface shape of the side facing the rotor permanent magnet 13 of the tooth head 5a constituting the stator iron core 2 is rotated by the rotor. A circular arc centered at the center and both end portions 5c and 5d form a tangential contact with both ends of the arc, respectively, the length of the air gap between the tooth head 5a and the rotor permanent magnet 13 in the circumferential direction It set so that the ratio of the both ends G2 with respect to the center G1 may be set to "2". Therefore, the induced voltage generated at the time of rotation of the permanent magnet motor 1 can be made very large, and both can be balanced so that the cogging torque and torque ripple are made very small. It is possible to suppress the occurrence of noise and noise.

Then, by forming both end portions 5c and 5d of the tooth head 5a to form a tangent plane leading to the center portion 5b, the change in the gap length from the center portion 5b to the both ends 5c and 5d is more gentle. This is more advantageous for adjusting the gap length.

(2nd Example)

FIG. 5 shows a second embodiment of the present invention, in which the same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. Only the other parts will be described below. In the second embodiment, the shape of the tooth head 15a of the tooth 15 is slightly different from the tooth head 5a.

That is, as shown in FIG. 5A, when the tooth head 15a faces the rotor permanent magnet 13, the surface shape of the side of the rotor permanent magnet 13 is circularly arced and three-dimensionally expressed, the rotor permanent magnet ( It forms the cylindrical surface which is convex toward 13). Also in this case, as in the first embodiment, the face shape of the tooth head 15a smoothly moves away from the rotor permanent magnet 13 as it faces both ends from the center, and the air gap length faces both ends. It gradually grows along. The air gap length G2 'at both ends is maximum, but the ratio with the air gap length G1' at the center is set to be 10:19.

FIG. 5B is a diagram corresponding to FIG. 1B. Also in this case, as in the first embodiment, as a result, when the ratio G2 '/ G1' is approximately 10:19, it can be seen that (organic voltage) / (cogging torque) shows almost maximum.

According to the second embodiment as described above, the air in the center is formed as a cylindrical surface in which the tooth head 15a faces the rotor permanent magnet 13 in a convex shape toward the rotor permanent magnet 13 side. The ratio between the gap length G1 'and the air gap length G2' at both ends was set to be 10:19. Therefore, almost the same effects as in the first embodiment can be obtained.

(Third Embodiment)

6 shows a third embodiment of the present invention. In the third embodiment, the present invention is applied to a permanent magnet type motor 20 of a high electric resistance type. In the stator core 16 of the stator, eight teeth 17 are provided on the inner circumferential side. In the center of the stator iron core 16, the rotor 19 provided with the rotor permanent magnet 18 is rotatably provided. And the surface shape of the side which opposes the rotor permanent magnet 18 in the tooth head 17a of the tooth 18 is an arc shape (cylindrical surface) centered on the position shifted in the outer peripheral direction of the stator core 16. As shown in FIG. )

Therefore, the shape of the surface of the tooth 17 facing the rotor permanent magnet 18 in the tooth head 17a smoothly moves from the rotor permanent magnet 18 toward both ends from the center in the circumferential direction. The air gap length between the tooth head 17a of the tooth 17 and the rotor permanent magnet 18 is made into the shape of being separated, and the gap length in both ends is set to G3 in the center of the circumferential direction, and Is G4,

It is set so that G4 / G3 = 2.

According to the third embodiment configured as described above, even when the present invention is applied to a permanent magnet-type motor of a civil war type, the same effects as in the second embodiment can be obtained.

The present invention is not limited to the embodiments described above and described in the drawings, but the following modifications or extensions are possible.

In the first embodiment, the air gap length ratio G2 / G1 between the tooth head and the rotor permanent magnet is not limited to "2". For example, even when the air gap length ratio is set in the range of 2.0 to 2.2, the range of 1.8 to 2.4, or the range of 1.6 to 2.6, it is possible to obtain advantageous effects.

In the second embodiment, the air gap length ratio G2 / G1 between the tooth head and the rotor permanent magnet is not limited to 10:19. For example, even when the air gap length ratio is set in the range of 1.8 to 2.0, the range of 1.6 to 2.2, or the range of 1.4 to 2.4, it is possible to obtain advantageous effects.

According to the stator iron core of the permanent magnet motor according to claim 1, a plurality of teeth are arranged radially with respect to the rotational axis, and convex to the permanent magnet side the face shape of the side facing the rotor permanent magnet of the tooth head, The gap length between the tooth head and the rotor permanent magnet was set so that the ratio of both ends to the center in the circumferential direction was in the range of 1.4 to 2.4. Therefore, when the motor provided with the stator iron core rotates, it is possible to optimize the balance of the generated state between the induced voltage and the cogging torque, and to prevent the occurrence of vibration or noise after extremely preventing the reduction of the efficiency of the motor. It becomes possible to suppress it.

According to the stator iron core of the permanent magnet motor according to claim 4, a plurality of teeth are arranged radially with respect to the rotation axis, and the center of the circumferential direction has a face shape on the side facing the rotor permanent magnet of the tooth head. A circular arc centered on the center of rotation of the shaft and both ends thereof make a tangential contact with both ends of the arc, and the length of the gap between the tooth head and the rotor permanent magnet in the circumferential direction is 1.6 to 2.6. The range was set. Therefore, the same effect as that of Claim 1 can be obtained, and the change of the gap length from the center part to both ends becomes more gentle, and adjustment of a gap length can be performed more easily.

Claims (7)

Placing a plurality of teeth radially about the axis of rotation, The convex shape of the side facing the rotor permanent magnet of the tooth head at the tip of the tooth is convex toward the permanent magnet side, The air gap between the tooth head and the rotor permanent magnet is set so that the ratio of both ends with respect to the center in the circumferential direction is in the range of 1.4 to 2.4. The surface of the side opposite to the rotor permanent magnet of the tooth head is convex toward the permanent magnet, The stator iron core of the permanent magnet motor is characterized in that the air gap length is set at a ratio of both ends with respect to the center in the circumferential direction in a range of 1.6 to 2.2. 3. The stator iron core of a permanent magnet motor according to claim 2, wherein the pore length is set in a range of 1.8 to 2.0 in the ratio of both ends to the center in the circumferential direction. Placing a plurality of teeth radially about the axis of rotation, The face shape of the side of the tooth head opposite to the rotor permanent magnet of the tooth head is arc-shaped with the center in the circumferential direction centered on the center of rotation of the rotor, and both ends thereof make tangents in contact with both ends of the arc. , The air gap between the tooth head and the rotor permanent magnet is set so that the ratio of both ends with respect to the center in the circumferential direction is in the range of 1.6 to 2.6. 5. The stator iron core of a permanent magnet motor according to claim 4, wherein the pore length is set at a ratio of both ends to a center in the circumferential direction in a range of 1.8 to 2.4. 6. The stator iron core of a permanent magnet motor according to claim 5, wherein the pore length is set at a ratio of both ends with respect to the center in the circumferential direction in the range of 2.0 to 2.2. The permanent magnet type motor provided with the stator iron core in any one of Claims 1-6.