JP2014039393A - Motor fastening structure and motor equipped with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor fastening structure in which an increase of an iron loss is reduced by compression stress generated when fitting such as shrinkage fitting between a housing and a stator is performed, and also to provide a motor equipped with the motor fastening structure.SOLUTION: A motor fastening structure includes: a housing 1 having a cylinder shape; a stator 6 having a cylindrically shaped stator core fitted inside the housing 1; a plurality of slots 9 arranged in the circumferential direction of the stator 6; and a magnetic pole tooth 3 integrated with the stator core formed between neighboring slots 9. A fitting position 7 where the housing 1 and the stator 6 are fitted to each other is only a root part of the magnetic pole tooth 3.

Description

  The present invention relates to a motor fastening structure suitable for use in a general general-purpose motor and a motor equipped with the same.

  An electromagnetic steel plate is used for a stator core of a general motor. In order to maintain a laminated structure in which a large number of electromagnetic steel sheets constituting the stator core are laminated, and as a means for increasing the bonding strength with the frame, coupling by shrink fitting is performed.

  However, it is known that the compressive stress generated when the stator core is shrink-fitted into the housing increases the iron loss. Iron loss is electrical energy lost when a coil is wound around an iron core of a magnetic material and magnetized by alternating current. Further, the magnitude of the iron loss depends on the iron loss characteristic of the steel sheet, and the iron loss characteristic of the steel sheet has a problem that it deteriorates due to stress applied by shrink fitting or the like.

  As a document disclosing measures against the problem of increasing the iron loss due to the stress of shrink fitting, there is Patent Document 1 below.

  In Patent Document 1, when the stator is shrink-fitted in a hermetic container of a compressor, a contact area that is in contact with the inner peripheral surface of the hermetic container disposed at a constant interval in the circumferential direction of the stator, and the contact area The non-contact area | region formed in is provided. The compressive stress generated during shrink-fitting can be concentrated at the contact end with the shell on the outer periphery of the stator that does not affect the magnetic path while maintaining the symmetry of the stress distribution. It has been shown to reduce iron loss.

JP 2008-193778 A

  As a result of diligent investigations by the present inventors, the magnetic flux density is concentrated near the intermediate position between the adjacent magnetic teeth, so if the compressive stress generated at the time of shrink fitting is applied near the position where the magnetic flux density is concentrated, iron loss occurs. I found out that it would grow.

  Moreover, if the shrinkage allowance of a stator and a container main body is taken large, the compressive stress concerning a container main body will also become large. Thereby, there existed a problem that an iron loss became large.

  In Cited Document 1, the stator is fitted into the closed container of the compressor by shrink fitting. A non-contact area is provided to remove the compressive stress generated during shrink fitting from the place where the magnetic flux easily passes, but since the contact part is provided in the vicinity where other magnetic flux densities are concentrated, the magnetic properties of the electrical steel sheet There is a problem that the iron loss cannot be greatly reduced.

  The present invention has been made in view of such circumstances, and includes a motor fastening structure that alleviates an increase in iron loss due to compressive stress generated during fitting such as shrink fitting between a housing and a stator. An object of the present invention is to provide a motor provided.

In order to solve the above problems, the motor fastening structure of the present invention and the motor including the same employ the following means.
The motor fastening structure of the present invention includes a housing having a cylindrical shape, a stator having a cylindrical stator core fitted inside the housing, and a plurality of slots arranged in a circumferential direction of the stator. Magnetic pole teeth integrated with the stator core formed between adjacent slots, and the fitting position where the housing and the stator are fitted is at the base of the magnetic teeth. It is characterized by being only.

  The fitting position where the housing and the stator are fixed by shrink fitting or the like is only the base portion of the magnetic teeth on which the coil formed between adjacent slots is wound. Since the magnetic flux density is not concentrated at the base part of the magnetic teeth, an increase in iron loss due to the influence of shrinkage residual stress can be prevented as much as possible. In addition, since the magnetic flux density is concentrated in the connecting portion that connects the adjacent base portions, the connecting portion is not set as the fitting position by setting the fitting position only to the base portion of the magnetic teeth. Thereby, motor efficiency can be improved and power consumption can be reduced.

  Further, in the motor fastening structure according to the present invention, the fitting position between the housing and the stator is provided only at one end in the axial direction.

  The shrinkage allowance can be reduced by fitting the housing and the stator only at one end in the axial direction. By reducing the shrinkage allowance, the stressed range can be narrowed and limited. Thereby, it can prevent that the iron loss by the influence of a residual stress increases.

  Furthermore, in the motor fastening structure according to the present invention, the stator is extended in the axial direction with respect to the rotor, and a fitting position with the housing is only an extension portion of the stator. To do.

  By extending the stator in the axial direction with respect to the rotor and fitting with the housing, the shrinkage allowance can be reduced while avoiding the location where the magnetic flux density is concentrated. By reducing the shrinkage allowance, the stressed range can be narrowed. Thereby, it can prevent that the iron loss by the influence of a residual stress increases.

  Furthermore, in the motor fastening structure according to the present invention, the housing is made of an aluminum alloy.

  Since a material having excellent processability such as an aluminum alloy is used, the shape of the housing can be easily processed. Thereby, the position adjustment between the suction path and the fitting position can be adjusted by processing the housing. Also, there is a difference in coefficient of linear expansion between aluminum and iron used as a motor material. For this reason, in order to prevent the motor from coming off due to a temperature difference, the shrinkage allowance, press fit allowance, or the shrink fit force or press input is often increased, and the motor stress due to press fit becomes larger than that of the iron housing. Therefore, it is effective for the aluminum housing.

  Furthermore, the motor according to the present invention includes the motor fastening structure described above.

  The motor is provided with a motor fastening structure that can prevent an increase in iron loss due to the effect of residual stress of shrink fitting. Thereby, motor efficiency can be improved and power consumption can be reduced.

  According to the present invention, the fitting position between the stator and the housing is only the base portion of the magnetic pole teeth where magnetic flux is difficult to pass. Thereby, it can reduce that the compressive stress which generate | occur | produces at the time of shrink fitting affects magnetic flux. Therefore, it is possible to prevent the iron loss of the motor from increasing. Since an increase in iron loss can be prevented, motor efficiency can be improved and power consumption can be reduced.

1 is a cross-sectional view showing a motor to which a motor fastening structure according to the present invention is applied. It is the sectional side view which showed 1st Embodiment of the motor fastening structure which concerns on this invention. It is the cross-sectional view which showed 2nd Embodiment of the motor fastening structure which concerns on this invention. It is the sectional side view which showed 3rd Embodiment of the motor fastening structure which concerns on this invention. It is detail drawing which showed the shrink fit position of the motor fastening structure which concerns on this invention.

Embodiments of a motor fastening structure according to the present invention and a motor including the same will be described below with reference to the drawings.
[First Embodiment]
1 and 2 are cross-sectional views illustrating a motor according to a first embodiment to which the motor fastening structure according to the present invention is applied.
As shown in FIG. 1, the motor 10 includes a rotor 2, a stator 6, and a housing 1 that accommodates them. The stator 6 is disposed on the inner peripheral surface of the housing 1, and the rotor 2 is rotatably disposed on the inner peripheral side of the stator 6.

  The rotor 2 is a cylindrical magnetic body that is concentric with the rotary shaft 8 and is configured by, for example, stacking electromagnetic steel plates in the axial direction. A plurality of permanent magnets (not shown) are arranged on the rotor 2 in the circumferential direction. The number of permanent magnets varies depending on the specifications of the motor 10. The rotating shaft 8 is rotatably supported by a bearing (not shown) included in the housing 1.

  The stator 6 is arranged with a slight gap around the outer periphery of the rotor 2. The stator 6 having a stator core is a magnetic body, and is configured by, for example, laminating electromagnetic steel plates in the axial direction.

  The stator iron core is formed with magnetic teeth 3 that protrude radially inwardly in the radial direction and are arranged at predetermined intervals in the circumferential direction. A conducting wire is wound around the slot 9 which is a groove-like space formed between the magnetic pole teeth 3. The conductive wire is wound around the magnetic pole teeth 3 while passing through the slot 9 to form the coil 4.

  The housing 1 and the stator 6 are fitted by shrink fitting. The position to be fitted by shrink fitting is only the root portion located on the radially outer peripheral side of the magnetic pole teeth 3. That is, the fitting position 7 between the housing 1 and the stator 6 is only the base portion of the magnetic pole teeth 3.

  The motor 10 to which the motor fastening structure of the housing 1 and the stator 6 shown in FIG. 1 is applied is an open type and semi-sealed type motor 10. A non-contact portion where the housing 1 and the stator 6 do not contact each other is used as a refrigerant suction path 5. Moreover, the material of the housing 1 used for the open type and semi-sealed motor 10 is, for example, aluminum.

Next, the operation of the motor fastening structure having the above-described configuration and the motor 10 including the same will be described.
As shown in FIG. 1, the housing 1 is a casting using, for example, aluminum, has a cylindrical shape, and has an inner peripheral surface processed into a circular shape. Moreover, the stator 6 has a cylindrical shape whose whole is open at both ends. The stator iron core is wound on the magnetic pole teeth 3 to form the stator 6, and the stator 6 is shrink-fitted at the fitting position 7 in the housing 1.

  Further, as shown in FIG. 2, the position where the stator 6 and the housing 1 are shrink-fitted is only the base portion of the magnetic pole teeth 3 and is the fitting position 7.

  In the motor 10 configured as described above, a rotating magnetic field is generated in the stator 6 by energization of the coil 4, and a force attracted by the rotating magnetic field is generated in the rotor 2 having a permanent magnet. Rotate. Thereby, the motor 10 outputs a predetermined torque from the rotating shaft 8.

  As shown in FIG. 5, when a rotating magnetic field is generated in the stator 6 by energization of the coil 4 of the motor 10, magnetic flux is generated and the magnetic flux density is concentrated in a circle A indicated by a dotted line. To do. When the stator 6 and the housing 1 are shrink-fitted in a circle where the magnetic flux density of the circle A is concentrated, the iron loss of the motor 10 increases due to residual stress at the time of shrink-fitting. Therefore, it fits by shrink fitting in the fitting position 7 removed from the range of the circle A where the magnetic flux density is concentrated.

According to this embodiment, there exist the following effects.
The fitting position 7 where the stator 6 and the housing 1 are shrink-fitted is only the root of the magnetic teeth 3. Since the magnetic flux density is not concentrated at the base portion of the magnetic teeth 3, an increase in iron loss due to the influence of residual stress due to shrink fitting can be prevented as much as possible. Moreover, since the magnetic flux density concentrates on the connection part that connects the adjacent root parts, the connection part is not set as the fitting position. Thereby, motor efficiency can be improved and power consumption can be reduced.

  Since the material of the housing 1 is made of a material having excellent workability such as aluminum, the shape of the housing 1 can be easily processed. Thereby, the position adjustment of the suction path 5 and the fitting position 7 can be adjusted by processing the housing 1. There is a difference in linear expansion coefficient between aluminum and iron used as the material of the motor 10. Therefore, in order to prevent the motor 10 from coming off due to a temperature difference, the shrinkage allowance, press fit allowance, or the shrink fit force or press input is often increased, and the stress of the motor 10 due to press fit becomes larger than that of the iron housing. Therefore, the present invention is effective for an aluminum housing. It is also effective for an iron housing.

  Since the magnetic flux does not concentrate at the fitting position 7, it is possible to perform shrink fitting by increasing the stress. Thereby, the location of the fitting position 7 between the housing 1 and the stator 6 can be reduced. The places to be fitted are, for example, three or more places. Further, since the stress for shrink fitting can be increased, it is possible to prevent the stator 6 and the housing 1 made of different materials from coming off due to a temperature change caused by the operation of the motor 10.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIG.
In this embodiment, the fitting position 7 with the stator 6 is the same as that in the first embodiment as shown in FIG. 1 in the circumferential direction, but the fitting position 7 in the axial direction is the same as that in the first embodiment. Different. That is, the fitting position 7 of this embodiment is provided only at one end in the axial direction as shown in FIG. Therefore, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.
As shown in FIG. 3, a portion where only a part of the stator 6 is extended in the axial direction and the housing 1 are shrink-fitted.

  According to the present embodiment, the shrinkage allowance can be reduced by fitting the housing 1 and a portion where only a part of the stator 6 is extended in the axial direction only at one end in the axial direction. By reducing the shrinkage allowance, the stressed range can be narrowed and limited. Thereby, it can prevent that the iron loss by the influence of a residual stress increases.

[Third Embodiment]
Next, a third embodiment of the present invention will be described with reference to FIG.
In this embodiment, the fitting position 7 with the stator 6 is the same as that in the first embodiment as shown in FIG. 1 in the circumferential direction, but the fitting position 7 in the axial direction is the same as that in the first embodiment. Different.
The stator 6 of the present embodiment is extended in the axial direction with respect to the rotor 2, and the fitting position 7 with the housing 1 is provided only at the extension portion of the stator 6. Therefore, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.
As shown in FIG. 4, the stator 6 is extended in the axial direction with respect to the rotor 2, and the fitting position 7 with the housing 1 is only an extension portion of the stator 6.

  According to this embodiment, the shrinkage allowance can be reduced by extending the stator 6 in the axial direction with respect to the rotor 2 and fitting the stator 6 with the housing 1. By reducing the shrinkage allowance, the stressed range can be narrowed. Thereby, it can prevent that the iron loss by the influence of a residual stress increases. Moreover, since the process which extends the stator 6 to an axial direction is performed, it can process easily compared with the process which extends only a part to an axial direction.

1 Housing 2 Rotor 3 Magnetic Teeth 4 Coil 5 Suction Path 6 Stator 7 Fitting Position 8 Rotating Shaft 9 Slot 10 Motor

Claims (5)

A housing having a cylindrical shape;
A stator having a cylindrical stator core fitted inside the housing;
A plurality of slots arranged in a circumferential direction of the stator;
Magnetic pole teeth integrated with the stator core formed between adjacent slots, and
The motor fastening structure is characterized in that a fitting position where the housing and the stator are fitted is only a base portion of the magnetic pole teeth.   The motor fastening structure according to claim 1, wherein the fitting position between the housing and the stator is provided only at one end in the axial direction.   The motor fastening structure according to claim 1, wherein the stator is extended in an axial direction with respect to the rotor, and a fitting position with the housing is only an extension portion of the stator.   The motor fastening structure according to claim 1, wherein the housing is made of an aluminum alloy.   A motor comprising the motor fastening structure according to claim 1.

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