JP3010624U - Rotor - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a rotor capable of suppressing magnetic flux leakage while ensuring sufficient axial strength. [Structure] The rotor magnet 12 is magnetized so that one side in the axial direction is an N pole and the other side is an S pole, and a through hole 14 is formed in the center in the axial direction. First magnetic pole core 16
Are arranged on one side of the rotor magnet 12. The second magnetic pole core 18 is arranged on the other side of the rotor magnet 12. The rotor shaft 20 is inserted into the through hole 14 of the low tag net 12 and is rotatable integrally with the rotor magnet 12 about the axis. The tubular body portion 22 is formed of a non-magnetic material into a tubular shape, and between the rotor shaft 20 and the rotor magnet 12, between the rotor shaft 20 and the first magnetic pole core 16 and the second magnetic pole core 18, Rotor shaft 20
It is externally fitted and interposed between the rotor magnet 12, the first magnetic pole core 16, the second magnetic pole core 18, and the rotor shaft 20 and can rotate around the axis.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a rotor, and more specifically, one side of a rotor magnet and one side of a rotor magnet in which one side in the axial direction is magnetized to N pole and the other side is magnetized to S pole, and a through hole is formed in the center in the axial direction. The first magnetic pole core attached to the rotor magnet, the second magnetic pole core attached to the other side of the rotor magnet, and the through hole of the rotor magnet are inserted to rotate integrally with the rotor magnet around the axis. Rotor for a motor with a possible rotor shaft.

[0002]

[Prior art]

 FIG. 2 shows a sectional view of a main part of a conventional hybrid type stepping motor. The rotor magnet 102 is magnetized so that the left side in the axial direction is the N pole and the right side is the S pole. A through hole 104 is formed in the center of the rotor magnet 102 in the axial direction. A first magnetic pole core 106 is attached to the left side of the rotor magnet 102, and a second magnetic pole core 108 is attached to the right side. The rotor shaft 110 is inserted into the through hole 104 of the rotor magnet 102. The rotor shaft 110 is rotatably supported by a ball bear link 112, and is rotatable integrally with the rotor magnet 102 about the axis. A spacer 114 is interposed between the ball bearing 112 and the first magnetic pole core 106 and the second magnetic pole core 108 to maintain a predetermined positional relationship. A rotor 100 including a rotor magnet 102 and a rotor shaft 110 is rotatable within a stator 116 including a coil. In the stepping motor of FIG. 2, when the coil of the stator 116 is selectively energized at a predetermined timing, the rotor 100 rotates about its axis.

[0003]

[Problems to be solved by the device]

 However, the above conventional rotor 100 has the following problems. Normally, the magnetic circuit by the magnetic force of the rotor magnet 102 is closed as shown by the arrow X. However, if the rotor shaft 110 is made of a magnetic material such as iron, the magnetic circuit shown by the arrow Y is closed in addition to the magnetic circuit shown by the arrow X. When the magnetic circuit shown by the arrow Y is closed, the magnetic flux passing through the magnetic circuit becomes a leakage magnetic flux, and there is a problem that the magnetic efficiency of the rotor magnet 102 is reduced. Therefore, it has been proposed that the rotor shaft 110 is made of, for example, a stainless steel-based non-magnetic material instead of a magnetic material, but the problem that the shaft strength is insufficient remains. Therefore, an object of the present invention is to provide a rotor capable of suppressing magnetic flux leakage while ensuring sufficient axial strength.

[0004]

[Means for Solving the Problems]

 In order to solve the above problems, the present invention has the following configuration. That is, one side in the axial direction is magnetized to the N pole, the other side is magnetized to the S pole, and a rotor magnet having a through hole formed in the center in the axial direction, and a first magnet disposed on the one side of the rotor magnet. Magnetic pole core, a second magnetic pole core arranged on the other side of the rotor magnet, and a rotor shaft that is inserted into the through hole of the rotor magnet and is rotatable integrally with the rotor magnet about an axis. A rotor provided with a tubular member made of a non-magnetic material, at least one of which is between the rotor shaft and the rotor magnet and between the rotor shaft and the first magnetic pole core and the second magnetic pole core. And a cylindrical portion that is externally fitted to the rotor shaft and is interposed between the rotor magnet, the first magnetic pole core, the second magnetic pole core, and the rotor shaft. And one It is characterized by being rotatable around the body.

[0005]

[Action]

 The operation will be described. Since the tubular portion is made of a non-magnetic material, it is possible to prevent the magnetic force of the rotor magnet from leaking to the through hole side. Further, since the tubular portion is fitted onto the rotor shaft, the strength of the rotor shaft can be reinforced by the provision of the tubular portion. In addition, the rotor shaft made of a magnetic material can be used, and the heat treatment of the rotor shaft can increase the strength.

[0006]

【Example】

 Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. In this embodiment, the rotor 10 used in the hybrid type stepping motor will be described as an example. First Embodiment In FIG. 1, 12 is a rotor magnet, which is formed in a cylindrical shape. The rotor magnet 12 is magnetized so that the left side in the axial direction is the N pole and the right side is the S pole. A through hole 14 is formed in the center of the rotor magnet 12 in the axial direction. Reference numeral 16 is a first magnetic pole core, which is formed of a magnetic material in a cup shape. The first magnetic pole core 16 is attached to the left end surface and the left outer peripheral surface of the rotor magnet 12. On the outer peripheral surface of the first magnetic pole core 16, a plurality of irregularities (not shown) are formed along the circumferential direction at a predetermined pitch to form a plurality of N pole magnetic pole pieces.

Reference numeral 18 denotes a second magnetic pole core, which is formed of a magnetic material in a cup shape. The second magnetic pole core 18 is attached to the right end surface and the right outer peripheral surface of the rotor magnet 12. On the outer peripheral surface of the second magnetic pole core 18, a plurality of irregularities (not shown) are formed at a predetermined pitch along the circumferential direction, and a plurality of S pole magnetic pole pieces are formed in the same number as the plurality of N pole magnetic pole pieces described above. Has been done. Further, the second magnetic pole core 18 is arranged such that the S-pole magnetic pole piece thereof is displaced from the N-pole magnetic pole piece of the first magnetic pole core 16 by a half pitch. As a result, a plurality of N poles and S poles are alternately arranged in the circumferential direction on the outer circumference of the rotor 10. Reference numeral 20 denotes a rotor shaft, which is made of a non-magnetic material such as stainless steel. The rotor shaft 20 is inserted into the through hole 14 of the rotor magnet 12.

Reference numeral 22 denotes a tubular portion, which is made of a non-magnetic material (for example, synthetic resin or stainless steel) and has a tubular shape. The tubular portion 22 is fitted onto the rotor shaft 20 and is also inserted into the through holes 14 of the rotor magnet 12, the first magnetic pole cores 16 and the central holes 24 and 26 of the second magnetic pole cores 18. The rotor shaft 20 is tightly fitted to the cylindrical portion 22 by press fitting, for example, and is not rotatable with respect to each other. Rollet eyes are formed on the outer peripheral surface of the cylindrical body portion 22 to facilitate press-fitting work when the first magnetic pole core 16 and the second magnetic pole core 18 are non-rotatably attached to the cylindrical body portion 22. The rotor magnet 12 is sandwiched by the first magnetic pole core 16 and the second magnetic pole core 18. Therefore, the rotor 10 including the rotor shaft 20, the tubular portion 22, the rotor magnet 12, the first magnetic pole core 16 and the second magnetic pole core 18 is integrally rotatable around the axis. In this embodiment, the inner diameter of the through hole 14 of the rotor magnet 12 is formed to be slightly larger than the outer diameter of the tubular portion 22, and the inner diameter of the rotor magnet 12 and the outer periphery of the tubular portion 22 are arranged between A tubular gap is created, which facilitates attachment of the rotor magnetette 12 to the tubular portion 22.

Reference numeral 32 is a pair of ball bearings, which are an example of bearings. The ball bearing 32 is fitted onto the rotor shaft 20 to rotatably support the rotor shaft 20. The bow bearings 32 are disposed on both sides of the tubular portion 22, and the inner end surfaces of the bow bearings 32 are in contact with the respective end surfaces of the tubular portion 22. With this configuration, movement of the tubular body portion 22 in the axial direction is restricted. Reference numeral 34 denotes a stator, which is fixed around the rotor 10. Although not shown, a plurality of coils formed by winding electric wires around a plurality of stator cores are arranged in the stator 34 in the circumferential direction. It is similar to a known stepping motor that the magnetic force is unbalanced between the plurality of magnetic pole pieces of the rotor 10 by selectively energizing the plurality of coils and the rotor 10 rotates about the axis. Is.

In the stepping motor of this embodiment, the magnetic circuit by the magnetic force of the rotor magnet 12 of the rotor 10 is closed as shown by arrow A. In this embodiment, since the rotor shaft 20 and the tubular portion 22 are made of a non-magnetic material, magnetic flux leakage (see the magnetic circuit Y in FIG. 2) does not occur on the through hole 14 side of the rotor magnet 12 as in the conventional case. . Therefore, it is possible to realize a highly efficient stepping motor without lowering the magnetic efficiency of the rotor magnet 12. Even if the rotor shaft 20 is made of low strength stainless steel, the cylindrical body portion 22 is fitted onto the rotor shaft 20. Therefore, the strength of the rotor shaft 20 can be reinforced by the provision of the cylindrical body portion 22. Becomes In particular, if the tubular portion 22 is made of a non-magnetic metal or a reinforced synthetic resin such as FRP, the rotor shaft 20 can be further reinforced and sufficient strength and rigidity can be obtained.

The rotor shaft 20 does not necessarily have to be formed of a non-magnetic material. For example, even if the rotor shaft 20 is made of magnetic metal, the magnetic flux leakage cannot be completely prevented, but the magnetic flux leakage can be suppressed by the provision of the cylindrical portion 22 made of a nonmagnetic material. When the rotor shaft 20 is made of an iron-based metal, sufficient strength and rigidity can be obtained, and since the workability is good, productivity and dimensional accuracy can be improved.

Second Embodiment In this embodiment, the inner diameter of the through hole 14 is formed to be larger than the outer diameter of the rotor shaft 20, and the tubular portion 22 includes the rotor shaft 20, the first magnetic pole core 16 and The rotor magnet 12 is interposed only between the second magnetic pole core 18 and the second magnetic pole core 18, and is sandwiched between the first magnetic pole core 16 and the second magnetic pole core 18. Also in this embodiment, since the tubular portion 22 is made of a non-magnetic material and an air gap is formed between the through hole 14 of the rotor magnet 12 and the rotor shaft 20, the magnetic flux leakage is the same as in the conventional case. Does not occur. Therefore, it is possible to realize an efficient stepping motor without lowering the magnetic efficiency of the rotor magnet 12.

Third Embodiment In the present embodiment, the cylindrical body portion 22 is inserted into the through hole 24 and is interposed between the rotor magnet 12 and the rotor shaft 20, and the first magnetic pole core 16 and the second magnetic pole core 16 are provided. The magnetic pole cores 18 are attached to both ends of the rotor magnet 12. Also in this embodiment, since the cylindrical portion 22 is made of a non-magnetic material and an air gap is formed between the first magnetic pole core 16 and the second magnetic pole core 18 and the rotor shaft 20, the same is true. No magnetic flux leakage to the rotor shaft 20 occurs. Therefore, it is possible to realize an efficient stepping motor without lowering the magnetic efficiency of the rotor magnet 12.

Although various preferred embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and, for example, a spacer between both ball bearings 32 can be formed in a conventional manner. Needless to say, more modifications can be made without departing from the spirit of the invention, such as by inserting 114 (see FIG. 2).

[0015]

[Effect of device]

 When the rotor according to the present invention is used, the cylindrical portion is made of a non-magnetic material, so that the magnetic forces in the rotor magnet, the first magnetic pole core, and the second magnetic pole core leak to the rotor shaft side. Can be suppressed. Therefore, since the leakage magnetic flux is suppressed, the magnetic efficiency of the rotor magnet is not reduced and an efficient motor can be realized. In addition, since the cylindrical portion is externally fitted to the rotor shaft, the strength of the rotor shaft can be increased by the amount of the cylindrical portion provided. Thus, the rotor shaft can also be formed and magnetic flux leakage can be prevented. When the configuration of claim 2 is adopted, since the tubular body portion is interposed between the rotor shaft and the rotor magnet and between the rotor shaft and the first magnetic pole core and the second magnetic pole core, Magnetic leakage to the rotor shaft can be reliably suppressed. When the configuration of claim 3 is adopted, the cylindrical portion is interposed between the rotor shaft and the first magnetic pole core and the second magnetic pole core, and the air gap is provided between the rotor shaft and the rotor magnet. Since a gap is created, magnetic leakage to the rotor shaft can be suppressed. When the configuration of claim 4 is adopted, the tubular body portion is interposed between the rotor shaft and the rotor magnet, and the first magnetic pole core and the second magnetic pole core are attached to both ends of the rotor magnet. Since there is an air gap between and, magnetic leakage to the rotor shaft can be suppressed. When the configuration of claim 5 is adopted, since the tubular body portion is formed of synthetic resin, it is easy to manufacture the tubular body portion. When the configuration of claim 6 is adopted, since the tubular body portion is made of non-magnetic metal, the strength of the rotor shaft can be further reinforced.

When the configuration of claim 7 is adopted, since the rotor shaft is made of non-magnetic metal, it is possible to prevent leakage magnetic flux. According to the structure of claim 8, since the rotor shaft is made of magnetic metal, the strength of the rotor shaft can be maintained high. Further, it is easy to process. Further, by using the rotor adopting the above configuration, it is possible to realize a motor with good magnetic efficiency in which magnetic flux leakage to the rotor shaft is suppressed.

[Brief description of drawings]

FIG. 1 is a sectional view of a main part of a hybrid type stepping motor using a first embodiment of a rotor according to the present invention.

FIG. 2 is a sectional view of a main part of a conventional hybrid type stepping motor using a rotor.

FIG. 3 is a sectional view of a main part showing a second embodiment of the rotor according to the present invention.

FIG. 4 is a sectional view of a main portion showing a third embodiment of the rotor according to the present invention.

[Explanation of symbols]

 10 Rotor 12 Rotor Magnet 14 Through Hole 16 First Magnetic Pole Core 18 Second Magnetic Pole Core 20 Rotor Shaft 22 Cylindrical Body Part

Claims (9)

[Scope of utility model registration request] 1. One side in the axial direction is an N pole and the other side is an S pole.
A rotor magnet that is magnetized to a pole and has a through hole formed in the center in the axial direction, a first magnetic pole core arranged on the one side of the rotor magnet, and a first magnetic pole core arranged on the other side of the rotor magnet. A rotor having a second magnetic pole core and a rotor shaft that is inserted into the through hole of the rotor magnet and is rotatable integrally with the rotor magnet about an axis; At least one of the rotor shaft and the first magnetic pole core and the second magnetic pole core is formed of a non-magnetic material in a tubular shape and is fitted onto the rotor shaft. A rotor in which a body portion is interposed, and the cylindrical body portion can rotate integrally with a rotor magnet, a first magnetic pole core, a second magnetic pole core, and a rotor shaft about an axis. 2. The cylindrical portion is interposed between the rotor shaft and the rotor magnet, and between the rotor shaft and the first magnetic pole core and the second magnetic pole core. The rotor according to claim 1, wherein: 3. The inner diameter of the through hole is formed to be larger than the outer diameter of the rotor shaft, and the cylindrical portion is provided between the rotor shaft and the first magnetic pole core and the second magnetic pole core. And the rotor magnet includes a first magnetic pole core and a second magnetic pole core.
It is sandwiched between the magnetic pole cores according to claim 1.
The described rotor. 4. The cylindrical body portion is inserted into the through hole and is interposed between the rotor magnet and the rotor shaft, and the first magnetic pole core and the second magnetic pole core are of a rotor magnet. The rotor according to claim 1, wherein the rotor is attached to both ends. 5. The rotor according to claim 1, wherein the cylindrical body is made of synthetic resin. 6. The rotor according to claim 1, wherein the cylindrical portion is made of a non-magnetic metal. 7. The rotor according to claim 1, wherein the rotor shaft is made of non-magnetic metal. 8. The rotor according to claim 1, wherein the rotor shaft is made of magnetic metal. 9. A motor comprising the rotor according to claim 1, 2, 3, 4, 5, 6, 7 or 8.