JP2002335642A - Rotary machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotary machine which can reduce torque ripples in a full operating condition. SOLUTION: A teeth 23 of a stator iron core 20 is formed of a base section 24 and a collar section 25 extending in both sides in the circumferential direction from the front end portion of the base section 24. The color section 25 is formed in the shape of staircase composed of a collar base section 25b extended in the circumferential direction from the base section 24 and a collar front end section 25a which is extended in the circumferential direction from the collar base section 25b and has the thin diameter direction thickness for the collar base section 25b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotating electric machine such as a motor, and more particularly, to a shape of a flange of teeth of a stator core capable of reducing a torque ripple in an entire operation range.

[0002]

2. Description of the Related Art FIG. 7 is a longitudinal sectional view schematically showing a configuration of a conventional magnetic pole concentrated winding motor, and FIG. 8 is an enlarged view showing a main part of a stator core applied to the conventional magnetic pole concentrated winding motor. . 7 and 8, the rotor 2 is formed in a cylindrical shape, and the permanent magnets 3 are arranged on the outer peripheral surface at an equal angular pitch in the circumferential direction. As the permanent magnet 3, a ferrite magnet, a neodymium magnet, a samarium cobalt magnet, or the like is used.

The stator 5 is formed by laminating magnetic thin plates made of a silicon steel plate or the like, and teeth 8 projecting radially inward from the inner peripheral surface of the cylindrical yoke portion 7. Stator core 6 formed on the surface at a predetermined pitch in the circumferential direction
And a stator winding 10 wound around the stator core 6. Each tooth 8 of the stator core 6 includes a base 8a having a predetermined tooth width, and flanges 8b protruding from both ends of the base 8a in the circumferential direction. In the stator core 6, a slot 9 is defined by a yoke portion 7 and adjacent teeth 8. Also, the stator winding 10
It is composed of windings 10 a for the number of the teeth 8,
0a is formed by winding a conductor wire around the base 8a of one tooth 8 a predetermined number of times. That is, the stator winding 1
A value of 0 means that the stator core 6 is wound around the magnetic poles in a concentrated manner.

[0004] The stator 6 constructed as described above is used for the rotor 2.
Are arranged coaxially so as to cover the outer circumference of the motor, and a current is applied to the stator winding 10 to magnetize the permanent magnets 3 so that the permanent magnets 3 adjacent in the circumferential direction have opposite polarities. Be completed. At this time, the radial end surface of each tooth 8 is formed in an arc surface so that the distance from the outer peripheral surface of the rotor 2 is evenly spaced, and the air gap 4 having a uniform gap length Lg is formed. It is formed between the rotor 2 and the stator 6.

In the conventional motor 1 configured as described above, when the permanent magnet 3 is magnetized, a large amount of short-circuit magnetic flux is generated between the opposed flange portions 8b, and the magnetic flux acting on the permanent magnet 3 of the rotor 2 is generated. There is a problem that the permanent magnet 3 cannot be efficiently magnetized. In order to solve this problem, a hole is formed in a part of the flange to increase the magnetic resistance between the opposed flanges, thereby reducing the short-circuit magnetic flux generated between the flanges, and acting on the permanent magnet. An attempt to increase the magnetic flux has been proposed in, for example, Japanese Patent Application Laid-Open No. 2000-166133.

In a conventional motor as an improvement described in Japanese Patent Application Laid-Open No. 2000-166133, as shown in FIG. 9, magnetic short circuit prevention holes 8c are provided at both ends in the circumferential direction of flange 8b of teeth 8A. Each is drilled.
In the conventional motor employing the stator core 6A configured as described above, the magnetic path between the opposed flanges 8b is reduced at the portion where the magnetic short-circuit preventing hole 8c is formed, that is, the magnetic resistance is increased, and The short-circuit magnetic flux generated at the time is reduced. This increases the magnetic flux acting on the permanent magnet when the permanent magnet is magnetized, so that the permanent magnet can be magnetized efficiently.
And

[0007]

As described above, a motor as a conventional improvement has been made for the purpose of improving the magnetizing characteristics of the permanent magnet, and it has been proposed that the variation of the material of the magnet and the variation of the magnet can be improved. No consideration has been given to a decrease in motor characteristics due to poor magnetization or the like. Therefore, the conventional motor as a remedy is insufficient for suppressing an increase in torque ripple due to variations in magnet materials and poor magnetization of the magnet. In other words, since a narrow portion is partially formed in the magnetic path in the vicinity of the facing flange 8b, the generation of a large short-circuit magnetic flux during magnetization can be suppressed by using the magnetic saturation of the magnetic path. There is a problem that the short-circuit magnetic path cannot be sufficiently saturated with respect to the magnetic flux generated during use, and the magnetic flux cannot be suppressed.

[0008] In view of the above, the present inventors have found that in producing a motor, machining errors such as variations in magnet materials and poor magnetization of the magnet occur, and these machining errors affect the torque ripple and cause motor characteristics. From the viewpoint of deteriorating the torque, a magnetic field analysis was performed with a focus on the relationship between the torque ripple and the slot opening width in order to suppress an increase in torque ripple caused by a machining error during normal use of the motor.

First, an ideal state free from machining errors will be described. Generally, in a permanent magnet motor driven by three-phase alternating current, a torque ripple having a frequency component of 6n times (n: natural number) of a power supply frequency is observed. It is known that the lower-order components of the torque ripple have a greater effect (hereinafter, these lower-order components are referred to as 6f components of the torque ripple). The 6f component of the torque ripple occurs only when power is supplied from the power supply, that is, occurs only in a load state. Here, La / L in the motor in the ideal state
FIG. 3 shows the results of a magnetic field analysis performed by the inventors regarding the relationship between g, the torque ripple, and the average torque. Note that La
Is the slot opening width, and Lg is the gap length of the air gap 4. In addition, the torque ripple indicates a 6f component,
It has been found that components other than the 6f component are hardly found. From FIG. 3, it can be seen that when the motor is designed to have a large La / Lg in an ideal motor load state without machining errors, the 6f component of the torque ripple can be reduced and the average torque can be increased. Therefore, in the ideal state,
By increasing the slot opening width La, torque ripple can be reduced.

Next, an actual state in which a machining error occurs will be described. That is, in an actual motor, machining errors such as variations in magnet materials and poor magnetization occur. It has been found from experiments and magnetic field analysis by the inventors that in this actual motor, in addition to the 6f component of the torque ripple, a torque ripple component due to the above-described machining error occurs. And the torque ripple component generated by the variation of the magnet is defined by the number of slots of the stator,
The number of pulsating components equal to the number of slots is generated per rotation (hereinafter referred to as torque ripple slot components). Here, FIG. 4 shows the results of a magnetic field analysis performed by the inventors regarding the relationship between La / Lg and the 6f component of the torque ripple and the average torque in the actual motor. From FIG. 4, it can be seen that, in the actual motor load state, the relationship between the 6f component of the torque ripple and the average torque and La / Lg is almost the same as the ideal motor load state without a machining error. Next, FIG. 5 shows the results of a magnetic field analysis performed by the inventors on the relationship between La / Lg and the torque ripple slot component in an actual motor. From FIG. 5, it can be seen that the slot component of the torque ripple increases almost in proportion to La / Lg when the motor is not loaded. Therefore, in the actual no-load state of the motor, it is desirable to design the slot opening width (La / Lg) small in order to reduce the torque ripple. On the other hand, in the actual motor load state, in addition to the torque ripple slot component, the torque ripple 6
An f component is generated. The slot component of the torque ripple under load does not depend much on La / Lg, as can be seen from FIG. 5, but the 6f component of the torque ripple decreases with increasing La / Lg, as can be seen from FIG. There is a tendency. Therefore, in order to reduce the torque ripple and increase the average torque in the actual motor load state, it is desirable to design La / Lg to be large.

The present inventors have found from the results of the magnetic field analysis on the relationship between the torque ripple and the slot opening width that, in an actual motor (actual machine) in which a machining error occurs, the entire operating range from a no-load state to a load state is considered. In order to reduce the torque ripple, it was found that it is desirable to reduce La / Lg in a no-load state and to increase La / Lg in a load state, and have arrived at the present invention. That is, according to the present invention, based on the above point of view, the flange shape of the teeth is devised so that the slot opening width is substantially different between the unloaded state and the loaded state, and the torque ripple is reduced in the entire operation range. An object of the present invention is to provide a rotating electric machine that can reduce the average torque and increase the average torque.

[0012]

A rotating electric machine according to the present invention has a base extending radially inward from an inner peripheral surface of an annular yoke, and a flange extending from a tip end of the base to both circumferential sides. Having a stator core having a plurality of teeth disposed on the inner peripheral surface of the yoke portion in the circumferential direction, and a stator winding wound around the stator core with magnetic pole concentrated winding. And, the stator is arranged coaxially so as to have an air gap on the inner peripheral side, a plurality of permanent magnets are disposed on the outer peripheral surface in the circumferential direction, and the permanent magnets adjacent in the circumferential direction have opposite polarities. In a rotating electric machine having a rotor that is magnetized, a flange portion of the teeth is provided with a flange base portion extending in a circumferential direction from the base portion, and a flange base portion extending in a circumferential direction from the flange base portion. Formed in a step-like shape consisting of a flange tip having a small radial thickness with respect to And those are.

Further, the stator core is formed by laminating magnetic thin plates in the axial direction, and the radial thickness of the tip end of the flange is equal to or greater than the thickness of the magnetic thin plate, and 2 mm of the thickness of the magnetic thin plate. It is formed less than twice.

The circumferential gap La between the circumferentially adjacent flange tips, the circumferential gap Lb between the circumferentially adjacent flange bases, and the gap length Lg of the air gap are defined by:
La <3.7Lg <Lb.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. Embodiment 1 FIG. FIG. 1 is a longitudinal sectional view showing a main part of a stator applied to a magnetic pole concentrated winding motor according to Embodiment 1 of the present invention, and FIG. 2 is a tooth tip of the magnetic pole concentrated winding motor according to Embodiment 1 of the present invention. It is an enlarged view which shows a part periphery. In each of the drawings, the same or corresponding parts as those in the conventional example shown in FIGS. 7 to 9 are denoted by the same reference numerals, and description thereof will be omitted.

In each of the figures, a stator 20 is formed by laminating magnetic thin plates made of silicon steel plate or the like in the axial direction, and has teeth 23 projecting radially inward from the inner peripheral surface of a cylindrical yoke portion 22. The stator includes a stator core 21 formed on the inner peripheral surface of the yoke portion 22 at a predetermined pitch in the circumferential direction, and a stator winding 10 wound around the stator core 21. Each tooth 23 of the stator core 21 includes a base 24 having a predetermined tooth width, and flanges 25 protruding from both ends of the base 24 in the circumferential direction. The stator core 21 includes
A slot 26 is defined by the yoke portion 22 and two adjacent teeth 23. The teeth 23 are formed in a circular arc surface such that the radial end surfaces thereof are uniformly spaced from the outer peripheral surface of the rotor 2 at equal intervals. And collar part 2
5 is a flange base 25b extending from the base 24 to both sides in the circumferential direction.
And a flange tip 2 extending from the collar base 25b to both circumferential sides.
5a. Flange base 25b
Is formed so that its radial thickness gradually decreases from the base 24 toward both sides in the circumferential direction.
The radial thickness is formed so as to gradually decrease from the flange base 25b toward both sides in the circumferential direction. Furthermore, the radial thickness of the base of the flange base 25b is Hsb,
When the radial thickness of the circumferential tip of the flange tip 25a is Hb, the radial thickness of the root of the flange tip 25a is Hsa, and the radial thickness of the circumferential tip of the flange tip 25a is Ha, Hsb >Hb>
Hsa> Ha. Also, the stator winding 10
Each of the windings 10a is formed of a plurality of windings 10a corresponding to the number of the teeth 23.
4 is formed by winding a predetermined number of times. That is, the stator winding 10 is wound around the stator core 21 by the magnetic pole concentrated winding method. Further, the permanent magnets 3 are arranged at an equiangular pitch on the outer periphery of the rotor 2, and the adjacent permanent magnets 3 are magnetized so as to have opposite polarities.

The stator 20 constructed as described above is arranged coaxially so as to cover the outer periphery of the rotor 2, and
Is completed. At this time, a uniform air gap 4 is formed between the rotor 2 and the stator 20.

In the no-load state of the motor 100 configured as described above, since no current flows through the stator winding 10, the magnetic flux density at the flange tip 25a of the flange 25 of the teeth 23 does not increase. Thereby, magnetic saturation of the flange tip 25a does not occur, and the slot opening width can be regarded as the distance between the adjacent flange tips 25a (corresponding to La in FIG. 2). That is, La / Lg is reduced, and the slot component of the torque ripple due to a machining error can be reduced. Further, in the load state of the motor 100, the magnetic flux generated by the current flowing through the stator winding 10 is
It flows through the flange base 25b from the flange tip 25a to the opposite flange tip 25a. Then, the magnetic flux density of the flange tip 25a becomes larger than the magnetic flux density of the flange base 25b, and the magnetic resistance of the flange tip 25a increases. Therefore, the slot opening width is determined by the distance between the adjacent flange bases 25b (Lb in FIG. 2). ). That is, at the time of energization, the slot opening width is equivalently increased. That is, La / L
g increases, and the 6f component of the torque ripple can be reduced.

As described above, according to the first embodiment, the flange 25 of the teeth 23 is formed to have a large thickness in the radial direction.
And is formed in a step-like shape comprising a flange tip portion 25a extending from the flange base portion 25b on both sides in the circumferential direction and having a smaller radial thickness than the flange base portion 25b. , The slot opening width is substantially reduced, and in a loaded state, the slot opening width is substantially widened. Therefore, in a no-load state, La / Lg becomes smaller,
And La / Lg (that is, Lb / Lg) in the load state
Is increased, so that a torque ripple can be reduced and the average torque can be increased in the entire operation range from the no-load state to the load state. Further, since the radial thickness of the flange base 25b is configured to gradually decrease toward both sides in the circumferential direction, the stator winding 1
0 is improved.

Further, the stator core 21 is formed by pressing a magnetic thin plate into a belt-like body having the yoke portion 22, the teeth 23 and the slots 26 formed thereon. It is manufactured by molding. Further, a ring-shaped body having the yoke portion 22, the teeth 23 and the slots 26 formed therein is formed from a magnetic thin plate by press forming, and a large number of such ring-shaped bodies are laminated. Or,
A long magnetic thin plate is press-formed to form a long strip having the yoke 22, the teeth 23 and the slots 26 formed thereon, and the strip is spirally wound. Therefore, if the radial thickness Ha of the circumferential tip of the flange tip 25a is too thin, the strength of the flange tip 25a is not ensured, and the flange tip 25a may be bent or broken in the stator core manufacturing process. As a result, the manufacturability of the stator core 21 deteriorates. Therefore, in consideration of the strength of the flange tip portion 25a, it is desirable that the radial thickness Ha be equal to or greater than the thickness (t) of the magnetic thin plate. This suppresses the occurrence of bending or breakage of the flange tip portion 25a in the manufacturing process of the stator core 21, thereby improving the yield. In addition, the flange tip 25a
Is smaller than twice the thickness (t) of the magnetic thin plate, a motor having good motor characteristics, that is, a small torque ripple and a large average torque can be realized. Therefore,
It is desirable that the radial thickness Ha of the flange tip portion 25a be t ≦ Ha ≦ 2t. Thereby, the manufacturability of the stator core is improved, and at the time of energization, the flange tip 25a can be sufficiently magnetically saturated, and a motor with small torque ripple can be obtained.

Here, when a machining error occurs, the 6f component and the slot component of the torque ripple and La / L
FIG. 6 shows the relationship with g. In FIG. 6, the relationship between the torque ripple under no load and La / Lg is the relationship between the slot component of the torque ripple and La / Lg in FIG. 5, and the relationship between the torque ripple under load and La / Lg. Is the relationship between the 6f component of the torque ripple in FIG. 4 and La / Lg. FIG. 6 shows that the 6f component of the torque ripple and the slot component intersect at La / Lg = 3.7. Therefore, in order to reduce the 6f component and the slot component of the torque ripple, La / Lg <
3.7, and it is desirable to satisfy Lb / Lg> 3.7 in a load state. That is, by setting La <3.7Lg <Lb, it is possible to achieve both reduction of the torque ripple and improvement of the motor efficiency (improvement of the DC torque with respect to the same current) in the entire operation range.

In the first embodiment, the collar base 25
The radial thickness of the root of b is Hsb, the radial thickness of the circumferential tip of the flange base 25b is Hb, the radial thickness of the root of the flange tip 25a is Hsa, and the circumferential direction of the flange tip 25a is Hsb. Assuming that the radial thickness of the tip is Ha, Hsb>Hb> Hsa
> Ha, but the flange shape is Hs
It may be formed so that b = Hb, Hsa = Ha, and Hb> Ha. Further, in the first embodiment, the flange distal end portion 25a is formed so that the radial thickness gradually decreases from the flange base portion 25b to both sides in the circumferential direction, but the flange distal end portion 25a has a radial thickness. The same effect can be obtained even if is formed so as to gradually increase from the flange base 25b to both sides in the circumferential direction. Further, in the first embodiment, the description has been given as applied to a motor. However, the present invention is not limited to a motor, and the same effects can be obtained even when applied to a rotating electric machine, for example, an AC generator. can get. Further, in the first embodiment, an example in which the air gap length Lg of the air gap is uniform has been described. Value is L
The same effect can be obtained by defining g.

[0023]

Since the present invention is configured as described above, it has the following effects.

According to the present invention, the tooth having the base extending radially inward from the inner peripheral surface of the annular yoke and the flange extending from the distal end of the base to both sides in the circumferential direction is provided by the yoke. A plurality of stator cores arranged in the circumferential direction on the inner peripheral surface of the portion, a stator having a stator winding wound around the stator core by magnetic pole concentrated winding, and an inner periphery of the stator. A rotor that is coaxially arranged to have an air gap on the side, a plurality of permanent magnets are circumferentially arranged on the outer peripheral surface, and the permanent magnets adjacent to each other in the circumferential direction are magnetized with opposite polarities. In the rotating electric machine provided with, the teeth flange portion,
It is formed in a step-like shape comprising a flange base extending circumferentially from the base and a flange tip extending circumferentially from the flange base and having a small radial thickness with respect to the flange base. Therefore, it is possible to obtain a rotating electric machine capable of reducing the torque ripple in the entire operation range.

Further, the stator core is formed by laminating magnetic thin plates in the axial direction, and the radial thickness of the tip end of the flange is equal to or greater than the thickness of the magnetic thin plate, and is 2% of the thickness of the magnetic thin plate. Since it is formed twice or less, the yield of the stator core is improved, and at the time of energization, the flange tip can be sufficiently magnetically saturated, and the torque ripple can be reduced.

A circumferential gap La between the circumferentially adjacent flange tips, a circumferential gap Lb between the circumferentially adjacent flange bases, and a gap length Lg of the air gap are defined by:
Since the relationship of La <3.7Lg <Lb is satisfied, the torque ripple can be reliably reduced in the entire operation range.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a main part of a stator applied to a magnetic pole concentrated winding motor according to Embodiment 1 of the present invention.

FIG. 2 is an enlarged view showing the vicinity of a tooth tip of the magnetic pole concentrated winding motor according to Embodiment 1 of the present invention.

FIG. 3 is a diagram showing a relationship between La / Lg, a 6f component of torque ripple, and an average torque in a magnetic pole concentrated winding motor having no machining error.

FIG. 4 is a diagram showing a relationship between La / Lg, a 6f component of torque ripple, and an average torque in a magnetic pole concentrated winding motor having a machining error.

FIG. 5 is a diagram showing a relationship between La / Lg and a torque ripple slot component in a magnetic pole concentrated winding motor having a working error.

FIG. 6 is a diagram illustrating a relationship between La / Lg and a 6f component and a slot component of a torque ripple in a magnetic pole concentrated winding motor having a machining error.

FIG. 7 is a longitudinal sectional view schematically showing a configuration of a conventional magnetic pole concentrated winding motor.

FIG. 8 is an enlarged view showing a main part of a stator core applied to a conventional magnetic pole concentrated winding motor.

FIG. 9 is an enlarged view showing a main part of a stator core applied to a conventional magnetic pole concentrated winding motor as an improvement measure.

[Explanation of symbols]

2 rotor, 3 permanent magnet, 4 air gap, 10
Stator winding, 20 stator, 21 stator core, 22
Yoke, 23 teeth, 24 base, 25 flange, 2
5a flange tip, 25b flange base, 100 motor (rotary electric machine).

Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat II (reference) H02K 21/16 H02K 21/16 MF term (reference) 5H002 AA01 AA09 AE07 5H615 AA01 BB01 BB02 BB14 BB16 PP01 SS03 SS05 SS51 5H621 AA02 GA01 GA04 GA16 GA18 HH01 JK05 5H622 AA02 CA02 CA05 DD01 DD02 DD06 PP03 QB01 QB09

Claims (3)

[Claims] 1. A tooth having a base extending radially inward from an inner peripheral surface of an annular yoke and flanges extending circumferentially on both sides from a distal end of the base is provided on an inner periphery of the yoke. A stator having a plurality of stator cores circumferentially disposed on a surface thereof; a stator having a stator winding wound around the stator core with magnetic pole concentrated winding; and an air gap on an inner peripheral side of the stator. And a rotor in which a plurality of permanent magnets are circumferentially arranged on the outer circumferential surface, and the permanent magnets adjacent in the circumferential direction are magnetized in opposite polarities. In the electric machine, a flange portion of the tooth is a flange base portion extending in a circumferential direction from the base portion, and a flange tip extending in a circumferential direction from the flange base portion and having a smaller radial thickness with respect to the flange base portion. A rotating electric machine characterized in that it is formed in a step-like shape comprising a part. 2. The stator core according to claim 1, wherein the stator core is formed by laminating magnetic thin plates in an axial direction. The rotating electric machine according to claim 1, wherein the rotating electric machine is formed to be twice or less. 3. A circumferential gap La between the circumferentially adjacent flange tips, a circumferential gap Lb between the circumferentially adjacent flange bases, and a gap length Lg of the air gap are La.
3. The rotating electric machine according to claim 1, wherein a relationship of <3.7 Lg <Lb is satisfied.