JPH08308156A - Permanent-magnet rotor - Google Patents

Abstract

PURPOSE: To reduce magnetic leakage from the driving shaft of a permanent- magnet rotor when shaft is made of a magnetic material by putting a roller yoke on the driving shaft and intercepting a magnetic circuit at, at least, one location between the driving shaft and the bearing. CONSTITUTION: In a brushless motor 1, a magnetic rotating shaft 7 rotatably supported by a bearing 5 and the magnetic rotating shaft 12 of a rotor 8 provided with magnetic pieces 11 for field in a rotor yoke 10 are coupled with each other in the inside diameter section of a nonmagnetic sleeve 15. The rotating shaft 12, the sleeve 15, and the rotating shaft 7 transmit the rotational force of the rotor 8 to the outside, at the same time, the shafts 12 and 7 maintain a constant interval in the sleeve 15 and inhibits the transmission of leak magnetic fluxes from the rotor 8. Therefore, the effective magnetic fluxes are increased and the efficiency of the motor 1 is improved. At the same time, higher torques can be transmitted due to the magnetic materials used for the shafts 7 and 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a permanent magnet rotor in which a permanent magnet piece for a field is inserted into the rotor yoke at the base of magnetic poles at substantially the same distance from the drive shaft. The present invention relates to a permanent magnet rotor that does not leak.

[0002]

2. Description of the Related Art Generally, a silicon yoke having an insertion opening for inserting a field magnet piece is laminated to form a rotor yoke, and the field magnet piece is press-fitted and inserted into the insertion opening of the rotor yoke. A permanent magnet rotor of such a brushless motor is known.

FIG. 7 shows a cross-sectional view of a conventional brushless motor. The brushless motor 51 is tightened by a bolt 52, and a pair of housing members 53, 54
The housing member 53 rotatably supports a single non-magnetic rotating shaft 57 by a bearing 55.
A rotor 58 is fixed to the rotating shaft 57, and one end of the rotating shaft 57 projects from the end surface of the housing member 53 and the rotor 58.
Is configured to be able to transmit the rotating force of the. A stator 59 is arranged around the rotor 58, and the stator 59 is sandwiched by the housing members 53 and 54.

The rotor 58 is composed of a rotor yoke 60 in which a large number of silicon steel plates are laminated and two field magnet pieces 61 inserted in the rotor yoke 60.

A part of the inside of the stator 59 constitutes a magnetic pole portion 66, and the magnetic pole portion 66 of the stator 59 faces the outer circumference of the magnetic pole portion 63 of the rotor with a slight distance therebetween. The stator coil 67 is connected to an external power source by a conductor 68.

FIG. 8 is a transverse cross-sectional view of the rotor yoke 60 having the field permanent magnet piece 61 inserted therein. In the rotor yoke 60, the pair of field permanent magnet pieces 61 are inserted into the opposite insertion openings 62 so that the N poles oppose each other. The generated magnetic flux passes through the inside of the rotor yoke, flows from the magnetic pole portion 63a to the external space of the permanent magnet rotor, and reaches the S pole of the magnetic pole piece 63b.
As a result, the magnetic pole portion 63a of the permanent magnet rotor has an N-pole magnetism, while the magnetic pole portion 63b has an S-pole magnetism.

At this time, the magnetic flux from the field permanent magnet piece 61 to the inside of the yoke has a magnetic rotary shaft that is as thin as possible.
If the torque is excessive, a non-magnetic rotating shaft is used.

[0008]

However, in the permanent magnet rotor described in the prior art, when the rotating shaft is an inexpensive magnetic rotating shaft, the inside of the rotor yoke is made up of two magnets incorporated in the rotor yoke. Due to the repulsion of the magnetic flux of the same pole, a part of the magnetic flux of the stator and a part of the magnetic flux of the rotor leak through the rotating shaft to the bearing and housing member, reducing the motor efficiency and attracting iron powder to the bearing. This not only causes a problem in durability but also causes noise. Therefore, in the conventional technique, a non-magnetic material is used for the rotating shaft. However, in a motor that uses a non-magnetic rotating shaft but requires a large torque, the rotating shaft is made thicker, so that the cost is higher than that of the magnetic rotating shaft, and at the same time, there is a problem in strength. It may be provided with an eccentric part, gear cutting, or processing on a pulley etc. on the rotating shaft itself that transmits rotational force to the outside, which causes quality and manufacturing problems such as durability and workability. Was.

Therefore, an object of the present invention is to solve the problems of the conventional permanent magnet rotor and to provide a permanent magnet rotor which uses a magnetic rotating shaft, has little magnetic flux leakage, is low in cost, and can maintain its performance. Is.

[0010]

According to the first aspect of the present invention,
The rotor yoke is made by stacking many steel plates and 2n on the outer circumference.
Magnetic drive in a permanent magnet rotor that has a magnetic pole of (n is a positive integer) and has a slot for inserting a permanent magnet piece for a field in every other base at substantially equal distances from the drive shaft. A rotor yoke is attached to the shaft, and at least one magnetic circuit is cut off between the drive shaft and the bearing.

According to a second aspect of the present invention, the rotor yoke is formed by laminating a large number of steel plates, has a magnetic pole of 2n (n is a positive integer) on the outer circumference, and has a base portion at every other distance from the drive shaft at substantially the same distance. In a permanent magnet rotor having a slot for inserting a magnetic permanent magnet piece, a rotor yoke is attached to a magnetic drive shaft, and the drive shaft and the drive shaft inserted into the bearing are made of a non-magnetic material. It is characterized by being connected by a sleeve.

According to a third aspect of the present invention, there is a through hole on the outer circumference of the sleeve, and a burr formed by processing the hole protrudes on the inner peripheral surface of the sleeve, whereby a gap is maintained between the respective rotary shafts. It is characterized by being

The invention according to claim 4 is characterized in that both ends of the sleeve are in contact with the rotor yoke and the bearing.

According to a fifth aspect of the present invention, the rotor yoke is formed by laminating a large number of steel plates, has a magnetic pole of 2n (n is a positive integer) on the outer periphery, and has a base portion at every other distance from the drive shaft at substantially equal distances. In a permanent magnet rotor having a slot for inserting a magnetic permanent magnet piece, a rotor yoke is attached to a magnetic drive shaft, and the drive shaft for transmitting torque is connected to the drive shaft by a non-magnetic sleeve. A bearing is installed on the outer circumference of the sleeve.

According to a sixth aspect of the present invention, the bearing is a metal bearing, and at the same time, a through hole exists in the outer periphery of the sleeve, and the hole is filled with bearing oil.

[0016]

【Example】

(Embodiment 1) An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a vertical sectional view showing an embodiment of the brushless motor of the present invention. The brushless motor 1 is tightened by a bolt 2 and has a pair of housing members 3 and 4, and the housing member 3 rotatably supports a magnetic rotary shaft 7 by a bearing 5.
Has one end protruding from the end surface of the housing member 3.

The rotor 8 is fixed to the magnetic rotary shaft 12, and one end of the rotary shaft 12 and the non-magnetic sleeve 1 are connected to the rotary shaft 7.
5 is connected at the inner diameter portion of the rotor 5, and the rotational force of the rotor 8
It is configured such that the rotational force can be transmitted to the outside through the sleeve 2, the sleeve 15, and the rotary shaft 7. Further, the rotary shaft 12, the sleeve 15 and the rotary shaft 7 are located on a straight line, and the rotary shaft 12 and the rotary shaft 7 are arranged inside the sleeve 15 at a constant distance so as to prevent transmission of leakage magnetic flux from the rotor 8. There is.

A stator 9 is arranged around the rotor 8,
The stator 9 is sandwiched by the housing members 3 and 4.

The rotor 8 is composed of a rotor yoke 10 in which a large number of silicon steel plates are laminated, and two field magnet pieces 11 inserted into the rotor yoke 10.

A part of the inside of the stator 9 constitutes a magnetic pole portion 16, and the magnetic pole portion 16 of the stator 9 is the magnetic pole portion 1 of the rotor.
It is opposed to the outer periphery of 3 with a slight distance. The stator coil 17 is connected to an external power source by a conductive wire 18.

FIG. 2 shows a cross-sectional view of the rotor yoke 10 having the permanent magnet pieces 11 for field magnets inserted therein. In the rotor yoke 10, since the pair of field permanent magnet pieces 11 are inserted into the opposite insertion ports 19 with the N poles facing each other, the N poles of the field permanent magnet pieces 11 are replaced by the repulsion of the magnetic flux. The generated magnetic flux passes through the inside of the rotor yoke, flows from the magnetic pole portion 13a to the external space of the permanent magnet rotor, and reaches the S pole of the magnetic pole piece 13b.
As a result, the magnetic pole portion 13a of the permanent magnet rotor has an N-pole magnetism, while the magnetic pole portion 13b has an S-pole magnetism. On the other hand, a small amount of magnetic flux also flows in the axial direction of the magnetic rotary shaft 12 through the magnetic flux inside the yoke from the field permanent magnet piece 11.

FIG. 3 shows a vertical cross-sectional view of the rotor yoke 10 having the field magnet permanent magnet pieces 11 inserted therein. In the rotor yoke 10, a pair of facing permanent magnet pieces 11 for field magnets are inserted and attached with their N poles facing the rotating shaft 12. One end of the magnetic rotary shaft 7 is supported by the bearing 5, and the other end of the magnetic rotary shaft 7 can transmit torque to the outside. In particular, the transmission portion of the external tokule is straight in the present embodiment, but in some cases, it is toothed, or in an air conditioner compressor, it is connected to an eccentric portion or a compression device. Therefore, the rotary shaft 7 is a magnetic rotary shaft that is easy to process and inexpensive. Also, a non-magnetic sleeve 15 that connects the rotating shaft 7 and the rotating shaft 12 on the same straight line.
Is arranged. The sleeve 15 is formed in a cylindrical shape, and the rotary shaft 7 and the rotary shaft 12 are connected to each other by a crimp or the like in the inner diameter portion. However, there is a through hole 20 penetrating the inside of the sleeve 15 in the outer peripheral portion, and the rotary shaft 7 and the rotary shaft 12 are not in contact due to the through hole 20.
Since the magnetic rotary shaft 12 and the magnetic rotary shaft 7 are not in direct contact with each other and the magnetic rotary shafts are connected by the non-magnetic sleeve 15, the pair of field permanent magnet pieces leak. The magnetic flux 21 does not flow to the rotating shaft 7 and the bearing 5. Further, since the leakage magnetic flux leaks only for a short distance of the rotating shaft 12, the effective magnetic flux contributing to the torque of the stator is increased.

Further, the sleeve 15 is brought into contact with the ends of the bearing and the rotor yoke so that the sleeve 15 can be positioned, and the rotary shaft 7 and the rotary shaft 12 can be positioned.
Since the bearing and the rotor yoke can be made straight, it can be manufactured at low cost and easily. Further, since the axial length of the sleeve 15 is a very short distance due to the installation between the end of the rotor yoke and the bearing 5, the sleeve 15 can be manufactured at low cost even if the sleeve 15 is a non-magnetic material. .

FIG. 4 is an enlarged vertical cross-sectional view of the joint portion of each rotary shaft inside the sleeve 15. The magnetic rotary shaft 7 and the magnetic rotary shaft 12 are joined to the inside of the sleeve 15. However, each rotating shaft is prevented from contacting with the rotating shaft 7 and the rotating shaft 12 by a burr 22 which is formed on the inner diameter of the sleeve and which is formed when the through hole 20 formed in the sleeve 15 is manufactured. As a result, the magnetic flux leaking from the rotor yoke is not transmitted to the rotary shaft 7 via the rotary shaft 12. If the gap between the rotary shaft 7 and the rotary shaft 12 is T1, then
It was found that when 1 mm or more, it was difficult to be transmitted to the rotating shaft 7, and when it was 2 mm or more, no magnetic flux was transmitted. Further, it is obvious that the gap T1 is larger than the diameter of the through hole 20 in manufacturing. Further, although the number of the through hole 20 is described as one in this embodiment, it is needless to say that the same effect can be obtained even if a plurality of through holes 20 are manufactured. Also sleeve 15
Is transmitted from the torque rotating shaft 12 generated between the rotor yoke and the stator, and is transmitted to the rotating shaft 7 so that eccentricity and twist do not occur.

(Embodiment 2) FIG. 5 shows a vertical sectional view of still another embodiment of the present invention.

In the rotor yoke 10, a pair of opposing field permanent magnet pieces 11 are inserted and attached with their N poles facing the rotating shaft 12. One of the magnetic rotary shafts 7 is fixed by a non-magnetic sleeve 25, and the other is capable of transmitting torque to the outside. In particular, in the present embodiment, the transmission part of the external tokule is straight, but in some cases, gear cutting is performed, and in the domestic compressor, it is connected to the eccentric part or the compression device. Therefore, the rotary shaft 7 is a magnetic rotary shaft that is easy to process and inexpensive. Further, a non-magnetic sleeve 25 that connects the rotating shaft 7 and the rotating shaft 12 on the same straight line is arranged. The sleeve 25 is formed in a cylindrical shape, and the rotary shaft 7 and the rotary shaft 12 are connected to each other by a crimp or the like in the inner diameter portion. However, there is a through hole 28 that penetrates the inside of the sleeve 25, and the rotary shaft 7 and the rotary shaft 12 are blocked from contact by the through hole 28. Further, since the magnetic rotating shafts are connected by the non-magnetic sleeve 15, the leaked magnetic flux 21 of the pair of field permanent magnet pieces leaks to the rotating shaft 7 and the bearing 5 provided on the outer peripheral portion of the sleeve 25. Absent. Further, since the leakage magnetic flux 27 leaks only for a short distance of the rotary shaft 12, the effective magnetic flux contributing to the torque of the stator is increased.

Further, the bearing 26 is composed of a metal bearing, the outer peripheral portion of which is fixed to the housing member (not shown), and the axial length thereof is set to be slightly shorter than the sleeve 25, and the end of the rotor yoke 10 is set. Since the gap T2 is set by the portion, it is set in a range where the magnetic flux directly leaked from the rotor yoke does not influence. The gap T2 is usually set to 1 mm or more,
Preferably, it is installed at 2 mm or more so that it is not affected by the leakage magnetic flux. A gap 29 is provided in the sleeve 25 and the bearing 26 so that the rotary shaft rotates. In the present invention, since the bearings are installed only on one of the left and right sides, the distance between the bearing 26 and the rotor yoke affects the vibration of the rotor. Therefore, since the bearing 26 of this configuration can be set close to the rotor yoke, it is possible to achieve very little rotor runout. Also, the axial length of the bearing can be set long.

The sleeve 25 has a through hole 28 on the outer peripheral surface that penetrates the inner diameter.

FIG. 6 is an enlarged vertical cross-sectional view of the joint portion of each rotary shaft inside the sleeve 25. The magnetic rotary shaft 7 and the magnetic rotary shaft 12 are joined to the inside of the sleeve 25. However, the rotary shafts 7 and 12 do not come into direct contact with each other due to the burrs 30 formed on the inner diameter of the sleeves, which are formed in the production of the through holes 28 provided in the sleeve 25. As a result, the magnetic flux leaking from the rotor yoke is not transmitted to the rotary shaft 7 via the rotary shaft 12. Bearing 26
There is a gap 29 for rotation between the sleeve 25 and the sleeve 25, the sleeve 25 has a through hole 28, and the bearing oil is filled inside. The rotation causes the oil to seep into the gap 29, It has a structure that minimizes wear with metal bearings. Also sleeve 25
Is greater than the thickness that is transmitted from the torque rotating shaft 12 generated between the rotor yoke and the stator and is not transmitted to the rotating shaft 7 to cause eccentricity, twist, etc., and the leakage magnetic flux is not transmitted to the bearing 26. It is set larger than the large size.

[0031]

According to the first and second aspects of the present invention, the rotor yoke is formed by laminating a large number of steel plates, has magnetic poles of 2n (n is a positive integer) on the outer circumference, and is substantially equal to the drive shaft. In a permanent magnet rotor having a slot for inserting a field permanent magnet piece at every other distance base, a rotor yoke is attached to a magnetic drive shaft, and the rotor yoke is inserted between the drive shaft and a bearing. Since the magnetic circuit is cut off, the amount of magnetic flux leakage is small and at the same time the effective magnetic flux is increased, leading to improved motor efficiency. In addition, a magnetic rotating shaft can be used as the rotating shaft, enabling transmission of high torque.

According to the third aspect of the present invention, there is a through hole in the outer circumference of the sleeve, and the burr processed in the hole projects to the inner peripheral surface of the sleeve, whereby the proper gaps of the respective rotary shafts are maintained. By doing so, it is possible to easily position the sleeve inside the rotary shaft, and it is easy to prevent the transmission of magnetic flux.

According to the fourth aspect of the invention, since the both ends of the sleeve are in contact with the rotor yoke and the bearing, the machining of the rotary shaft is simplified and the cost is reduced.

According to the invention of claim 5, a rotor yoke is attached to the magnetic drive shaft, and the drive shaft for transmitting torque to the outside is connected by a non-magnetic sleeve.
Since the bearing is installed on the outer circumference of the sleeve, the bearing can be installed up to the vicinity of the end portion of the rotor yoke, so that the eccentricity of the rotor yoke is significantly reduced.

According to the sixth aspect of the present invention, the bearing is a metal bearing, and at the same time, a through hole exists in the outer periphery of the sleeve, and the hole is filled with bearing oil. Wear due to friction with the sleeve has been significantly reduced.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a brushless motor of the present invention.

FIG. 2 is a cross-sectional view of the rotor yoke of the present invention.

FIG. 3 is a vertical sectional view of a rotor yoke of the present invention.

FIG. 4 is an enlarged vertical sectional view of the sleeve of the present invention.

FIG. 5 is a vertical sectional view of a rotor yoke according to another embodiment of the present invention.

FIG. 6 is a vertical cross-sectional view of a sleeve according to another embodiment of the present invention.

FIG. 7 is a vertical sectional view of a conventional brushless motor.

FIG. 8 is a cross-sectional view of a conventional rotor yoke.

[Explanation of symbols]

 1 Brushless Motor 2 Bolts 3,4 Housing Member 5 Bearing 7,12 Rotating Shaft 8 Rotor 9 Stator 10 Rotor Yoke 11 Field Magnet Piece 13,16 Magnetic Pole 15,25 Sleeve 17 Stator Coil 18 Conductor 20,28 Through Hole 21, 27 magnetic flux 30 burr

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical indication H02K 21/14 H02K 21/14 M 29/00 29/00 Z

Claims (6)

[Claims] 1. A rotor yoke is formed by laminating a large number of steel plates, has magnetic poles of 2n (n is a positive integer) on the outer periphery, and has permanent magnet pieces for field magnets at every other base at substantially equal distances from the drive shaft. In a permanent magnet rotor having a slot adapted to be inserted, a rotor yoke is attached to a magnetic drive shaft, and at least one magnetic circuit is cut off between the drive shaft and the bearing. Permanent magnet rotor. 2. A rotor yoke is formed by laminating a large number of steel plates, has magnetic poles of 2n (n is a positive integer) on the outer periphery, and has permanent magnet pieces for field magnets at every other base at substantially equal distances from the drive shaft. In a permanent magnet rotor having a slot for insertion, a rotor yoke is attached to a magnetic drive shaft, and the drive shaft and the drive shaft inserted in the bearing are connected by a sleeve made of a non-magnetic material. A permanent magnet rotor characterized in that 3. A through hole is formed on the outer circumference of the sleeve, and burrs formed by processing the hole project to the inner peripheral surface of the sleeve, whereby gaps are maintained between the respective rotary shafts. The permanent magnet rotor according to claim 2. 4. The permanent magnet rotor according to claim 2, wherein both ends of the sleeve are in contact with the rotor yoke and the bearing. 5. The rotor yoke is formed by laminating a large number of steel plates, has magnetic poles of 2n (n is a positive integer) on the outer periphery, and has permanent magnet pieces for field magnets at every other bases at substantially the same distance from the drive shaft. In a permanent magnet rotor having slots to be inserted, a rotor yoke is attached to a magnetic drive shaft, and the drive shaft for transmitting torque to the drive shaft is connected by a non-magnetic sleeve. A permanent magnet rotor characterized in that a bearing is installed. 6. The permanent magnet rotating device according to claim 5, wherein the bearing is a metal bearing, and at the same time, a through hole is formed in the outer circumference of the sleeve, and the hole is filled with bearing oil. Child.