JP2012161126A - Electric motor, compressor, and apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric motor which reduces the increase of an iron loss due to welding even when fixed to a housing by welding and thereby achieving high efficiency.SOLUTION: An electric motor of this invention is composed of a stator 10 and a rotor 20, and the stator 10 has an annular yoke 14 and multiple teeth 12 disposed on an inner peripheral part of the yoke. Three phase concentrated winding coils 13 are wound around the teeth through an insulator (an insulation film, an insulator, the like: not shown in the figure). The annular yoke 14 is fixed to a housing 30 by welding, and the welding is performed on the teeth outer peripheral side yoke 11 positioned on the teeth outer peripheral side.

Description

  The present invention relates to a high-efficiency electric motor and a compressor or other device equipped with the same.

  As a method of fixing the electric motor and the housing, shrink fitting is known as a well-known technique. As an example of an electric motor fixed by shrink fitting, an electric motor that has been improved in efficiency by suppressing an increase in iron loss of the electric motor has been proposed (for example, see Patent Document 1). In the case of Patent Document 1, the stator yoke portion is provided with a component that does not come into contact with the housing in order to suppress an increase in iron loss due to the influence of stress caused by shrink fitting. Higher efficiency is achieved by mitigating the effects of

JP 2004-201428 A

  When fixing by shrink fitting is used in the process of the electric motor, the iron loss increases due to the stress and the efficiency decreases. Therefore, in Patent Document 1, an increase in iron loss due to stress is suppressed and high efficiency is achieved by preventing contact between the stator yoke and the housing through which a large amount of magnetic flux flows. However, it is considered that there is a limit with considerable difficulty in completely eliminating the stress due to shrink fitting.

  For example, when the thickness of the housing is large, the effect of suppressing the increase in iron loss is small because the stress due to shrink fitting is large. Also, when the interference fit increases due to variations or the like, the effect of suppressing the increase in iron loss is reduced, and the efficiency is lowered. Furthermore, a yoke groove 17 for preventing contact with the housing must be provided in the yoke of the stator through which a large amount of magnetic flux flows, which increases the magnetic flux density of the yoke portion and causes an increase in iron loss.

  This invention is made | formed in view of the above-mentioned conventional subject, The objective is suppressing the increase in the iron loss by fixation by selecting it by welding fixation, without selecting the fixation by shrink fitting. Provide a highly efficient electric motor.

  In order to solve the above-described conventional problems, a first invention according to the present application includes an annular yoke and a plurality of teeth disposed on an inner peripheral portion of the yoke, and windings are provided on the plurality of teeth. The fixed stator is opposed to the inner periphery of the stator via a slight gap, is rotatably held, and is constituted by a rotor provided with a permanent magnet inside or on the surface of the rotor core. In the electric motor in which a part of the outer periphery of the core is fixed to the housing by welding, the electric motor has a configuration in which the welding position is a yoke portion having a low magnetic flux density. According to the above invention, an increase in iron loss due to fixing can be suppressed by setting the welding position to a yoke portion having a low magnetic flux density.

  The second invention according to the present application is the first invention, wherein the winding is a concentrated winding, and the welding position is a yoke portion located on the outer peripheral side of the teeth. It is an electric motor. By the said invention, the position of the said welding is made into the yoke part located in the outer peripheral side of the said teeth, and the iron loss increase by fixation can be suppressed.

  The third invention according to the present application is the first and second inventions, wherein the yoke part and the housing part are supplementarily shrink-fitted or press-fitted together with the fixing by welding. It is an electric motor. According to the above invention, play between the stator yoke portion and the housing can be prevented, and the fixing accuracy is improved. Moreover, since it is shrink-fitted or press-fitted auxiliary, an increase in iron loss due to stress can be suppressed.

  A fourth invention according to the present application is the electric motor according to any one of the first to third inventions, wherein the yoke portion located on the outer peripheral side of the teeth portion includes a hole penetrating in the axial direction. According to the above invention, by providing a hole penetrating in the axial direction in the yoke portion located on the outer peripheral side of the tooth portion, heat at the time of welding is not transferred to the tooth portion, and thermal deformation of the tooth portion is suppressed it can.

  A fifth invention according to the present application is the electric motor according to any one of the first to fourth inventions, wherein the hole has a substantially triangular shape. According to the above invention, by making the shape of the hole substantially triangular, the flow of magnetic flux is not hindered, and an increase in iron loss can be suppressed.

  In addition, in a sixth invention according to the present application, in the first to fifth inventions, the lower limit value of the thickness of the bridge constituting the hole shape is 1/2 of the diameter of the weld hole of the housing. It is an electric motor which comprises. According to the above invention, when the thickness of the bridge constituting the shape of the hole is set to ½ or more of the diameter of the welding hole of the housing, it is possible to prevent spatter during welding.

  A seventh invention according to the present application is the electric motor according to any one of the first to sixth inventions, wherein a perfect circle hole is provided at each end of the hole. According to the above invention, by providing a perfect hole at both ends of the hole, an increase in iron loss due to the stress can be suppressed even when a shrinkage stress is applied.

  An eighth invention according to the present application is a compressor provided with the electric motors according to the first to seventh inventions. According to the above invention, the compressor exhibits the effects and advantages of any one of the first to seventh inventions.

  A ninth invention according to the present application is an apparatus including the electric motor according to the first to seventh inventions. According to the above invention, the device exhibits the operations and effects of the corresponding first to seventh inventions.

  ADVANTAGE OF THE INVENTION According to this invention, the iron loss increase at the time of fixing a stator yoke part and a housing part can be made small, and a highly efficient electric motor can be provided.

Radial sectional view showing an embodiment The schematic diagram of the through-hole to which welding which shows one Embodiment is given The schematic diagram showing the relationship between the bridge which comprises the through-hole which shows one Embodiment, and the welding hole of a housing The schematic diagram which provided the perfect circle hole in the both ends of the through-hole which shows one Embodiment Radial cross section showing prior art

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 is an embodiment of the present invention and is a sectional view in the radial direction. As shown in this figure, the electric motor of the present invention comprises a stator 10 and a rotor 20, and the stator 10 has an annular yoke 14 and a plurality of teeth 12 arranged on the inner peripheral portion of the yoke, A winding 13 of a three-phase concentrated winding is applied via an insulator (insulating film, insulator, etc .: not shown). The annular yoke 14 and the housing 30 are fixed by welding, and the welding is applied to the yoke 11 on the outer peripheral side of the tooth located on the outer peripheral side of the tooth. The annular yoke 14 (other than the yoke portion located on the outer peripheral side of the tooth 12) has a high magnetic flux density, and when the annular yoke 14 portion is welded, the iron loss at the welded portion increases. However, the yoke 11 on the outer peripheral side of the tooth located on the outer peripheral side of the tooth has a small amount of magnetic flux flowing and a low magnetic flux density, so that an increase in iron loss due to welding is small. Therefore, if the yoke 11 on the outer peripheral side of the tooth positioned on the outer peripheral side is fixed by welding, the increase in iron loss is small and a highly efficient electric motor can be obtained.

  In addition, although the said form is a form with a concentrated winding, the same effect is acquired also in the case of a distributed winding, if the yoke part with a low magnetic flux density is made into the position which welds.

  In addition, the annular yoke 14 and the housing 30 are supplementarily shrink-fitted or press-fitted and fixed by welding, so that the accuracy of fixing the annular yoke 14 and the housing 30 is improved. Noise due to 10 unequal GAPs is reduced, and a low noise and high efficiency electric motor can be obtained.

  FIG. 2 is a diagram showing the shape of the through hole, which is an embodiment of the present invention. A through hole 15 penetrating in the axial direction is provided in the yoke 11 on the teeth outer peripheral side located on the outer peripheral side of the teeth. By providing the through hole, heat at the time of welding becomes difficult to be transmitted to the teeth 12, and thermal deformation of the teeth 12 can be suppressed. As a result, the accuracy of the GAP can be ensured, noise and the like due to GAP mismatch can be reduced, and a low noise and high efficiency electric motor can be obtained. Moreover, the yoke 11 on the outer periphery side of the tooth located on the outer periphery side of the tooth has a small amount of magnetic flux flowing, and can maintain high efficiency even if a through hole is provided. Further, when the electric motor of the present invention having this through hole is applied to a compressor, the through hole can be used as a passage through which a refrigerant flows, and a highly efficient compressor can be realized. In addition, when the electric motor of the present invention having this through hole is applied to a device, the through hole can be used as a heat radiating hole, temperature rise is suppressed, and a highly efficient device can be realized.

When designing the through hole, considering the flow of magnetic flux, the 15a portion of the through hole is made to be a concentric arc of the slot 14a portion constituting the annular yoke 14 or its equivalent, and the shape is made to be a triangular shape. The flow is not obstructed, and further efficiency improvement is possible.
FIG. 3 is a schematic view showing the relationship between the bridges constituting the through holes and the weld holes of the housing, showing an embodiment. By setting the thickness Bt of the bridge 16 constituting the through hole to be 1/2 or more of the diameter Yt of the welding hole 40 of the housing, it is possible to prevent spatter during welding and to obtain a high-quality electric motor.

  FIG. 4 is a schematic view showing a round hole provided at both ends of the through hole according to an embodiment. Even if the stator 10 and the housing 30 are auxiliary, if they are shrink-fitted or press-fitted, stress is applied to the yoke 14 and iron loss increases. As a countermeasure, a highly efficient electric motor can be obtained by providing perfect circular holes at both ends of the through hole to relieve stress. Furthermore, the electric motor of the present invention is mounted on a compressor and other devices.

  Even if the stator of the electric motor is used as a magnetizing yoke of the rotor, it is possible to provide a low-cost, high-insulation stator having high insulation performance that is resistant to magnetization stress, and a method of insulating the stator winding.

DESCRIPTION OF SYMBOLS 10 Stator 11 Teeth outer yoke 12 Teeth 13 Winding 14 Yoke 15 Through hole 16 Bridge 17 Yoke groove 20 Rotor 30 Housing 40 Welding hole

Claims (9)

A stator having an annular yoke and a plurality of teeth disposed on the inner peripheral portion of the yoke, and winding the plurality of teeth; and a slight gap in the inner periphery of the stator In the electric motor which is opposed to and is rotatably supported, and is constituted by a rotor provided with a permanent magnet inside or on the surface of the rotor core, and a part of the outer periphery of the stator core is fixed to the housing by welding. An electric motor having a configuration in which a position where welding is performed is a yoke portion having a low magnetic flux density. The electric motor according to claim 1, wherein the winding is a concentrated winding, and the welding position is a yoke portion located on an outer peripheral side of the teeth. 3. The electric motor according to claim 1, further comprising a configuration in which the yoke portion and the housing portion are supplementarily shrink-fitted or press-fitted together with the fixing by welding. 4. The electric motor according to any one of claims 1 to 3, wherein a hole penetrating in an axial direction is provided in a yoke portion positioned on an outer peripheral side of the tooth portion. The electric motor according to any one of claims 1 to 4, wherein the hole has a substantially triangular shape. The electric motor according to any one of claims 1 to 5, wherein a lower limit value of a thickness of a bridge constituting the shape of the hole is ½ of a diameter of a weld hole of the housing. The electric motor according to any one of claims 1 to 6, wherein perfect holes are provided at both ends of the hole. The compressor provided with the electric motor as described in any one of Claims 1 thru | or 7. The apparatus provided with the electric motor as described in any one of Claims 1 thru | or 7.

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