JP2005354870A - Stator of motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the stator of a motor which can prevent the deterioration of magnetic characteristics by the compression stress of the case that an outer frame is fixed in contact with the stator of the motor, and which can prevent the decrease of a motor efficiency. <P>SOLUTION: In the motor having the stator which has a plurality of teeth in a circumferential direction and the outer frame for fixing in contact the stator, the outer periphery of the stator in which the root of the teeth is positioned, is fixed in contact to the outer frame. An air gap for alleviating the stress near the outer periphery of the stator is provided between the root of the teeth and the outer periphery of the stator fixed in contact to the outer frame. Consequently, the stator of the motor can be made in which the compression stress applied to the stator of the motor is reduced to prevent the deterioration of the magnetic characteristics. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a stator having a plurality of teeth portions in a circumferential direction and an electric motor in which the stator is contact-fixed to an outer frame.

Conventionally, the stator of an electric motor mounted on a compressor which is a driving source for an air conditioner or a refrigerator is
The stator is fixed directly to the case which is the outer frame. The stator of the motor is a shrinking method that heats the case to a high temperature and is assembled to the stator, or a cooling method that cools the stator of the motor and is assembled to the case, and the stator is fixed to the case with a slight tightening allowance. A press-fitting method or the like is used. In addition, the stator of an electric motor can be easily fixed and assembled | attached to a case by using a shrink-fitting method and a cooling swallow method together.

  When the stator of the electric motor is fixed to the case in this way, an allowance is provided between the stator and the case to some extent so that the stator does not loosen (does not fall off) from the case during operation of the electric motor. However, since the case for fixing the stator is formed by drawing or deep drawing, the dimensional tolerance is large, and when the stator is assembled to the case, the tightening margin is too large, or the stator is deformed, or There is a problem that the tightening margin is too small and the stator loosens and falls off from the case.

To solve these problems, for example, as disclosed in Japanese Patent Application Laid-Open No. 5-268740 (see Patent Document 1), a contact-fixed fitting in a compressor for a refrigeration cycle in which a stator of an electric motor is fixed in contact with a case. A slit longer than the circumferential length of the mating portion is provided along the outer peripheral surface of the stator.
This prevents the stator from being deformed by elastically deforming the outer diameter of the stator by the slit provided in the stator and absorbing the dimensional tolerance generated in the case.

  In addition, when the case is fixed to the stator by the shrinkage method as described above, the contraction force of the case acts on the stator as a compressive force, which deteriorates the magnetic characteristics of the stator and reduces the motor efficiency. Yes. In response to such a problem, for example, as disclosed in Japanese Patent Application Laid-Open No. 2002-136003 (see Patent Document 2), the stress generated during shrink-fitting of the case is relaxed by a hole provided in the stator, and the magnetic characteristics are deteriorated. There has been proposed an electric motor with reduced noise.

Japanese Patent Laid-Open No. 5-268740 JP 2002-136003 A

  When fixing the stator of a conventional electric motor to the case by shrinkage or the like, stress proportional to the tightening margin is generated. Therefore, as a method of relieving this stress, a slit (hole) is provided on the outer periphery of the stator. However, depending on the slits provided in the stator, the case is provided in the stator in order to reduce the force with which the case tries to hold the stator and the stator falls off or the increase in iron loss due to stress is reduced. Regardless of the slit, the magnetic flux path is compressed, and there is a case where the efficiency of the motor is deteriorated. In view of the above, the present invention provides a gap at an appropriate position to relieve stress generated in the vicinity of the outer peripheral surface of the stator, thereby reducing the deterioration of magnetic characteristics as much as possible, and the gap between the case and the stator. It is an object of the present invention to obtain a stator of an electric motor in which the holding force is not lowered and the stator does not fall off.

The invention described in claim 1 is an electric motor including a stator of an electric motor having a plurality of teeth portions in a circumferential direction, and an outer frame that contacts and fixes the stator.
The stator outer periphery where the teeth base of the stator is located is fixed in contact with the outer frame, and the stator teeth base of the stator and the stator outer periphery fixed in contact with the outer frame (case). In the meantime, by providing a gap to relieve stress in the vicinity of the outer periphery of the stator, it is possible to reduce the compressive stress due to shrinkage as much as possible, and to prevent deterioration of magnetic properties due to stress, and to prevent iron loss of the stator. It is possible to prevent the increase. In this case, the gap may be at least one gap between the root of the teeth portion and the outer periphery of the stator fixed in contact with the outer frame, and a plurality of teeth provided in the circumferential direction of the stator. It is not always necessary to provide a gap between all the teeth bases and the outer periphery of the stator, and the number and size of the gaps may be appropriately selected as necessary.

  According to a second aspect of the present invention, a gap is provided between the root of the stator portion of the stator and the outer periphery of the stator fixed in contact with the outer frame, and the gap is formed from the root of the teeth portion of the stator. By providing a bridge part that crosses the outer periphery of the stator fixed in contact with the frame, the stator is securely fixed to the outer frame by the bridge part that crosses the gap, together with a gap that prevents deterioration of the magnetic characteristics of the stator. It can be set as the stator of the electric motor which a stator does not drop from a frame.

  According to a third aspect of the present invention, an opening angle of the outer periphery of the stator that is centered on the inner diameter center of the stator and is fixed in contact with the outer frame is provided to relieve stress in the vicinity of the outer periphery of the stator. By making the opening angle equal to or larger than the opening angle of the gap, the vicinity of the outer periphery of the stator is not buckled by the compressive stress when the outer frame is contacted and fixed to the stator, and the gap is not depressed. As a result, the outer periphery of the stator fixed in contact with the outer frame is not permanently deformed and the stator is not loosened (dropped off) from the outer frame, so that the stator can be securely fixed.

  According to a fourth aspect of the present invention, the outer periphery of the stator where the teeth base of the stator is located is fixed in contact with the outer frame, and the outer periphery of the stator where the slot bottom provided in the stator is positioned is the outer frame. , So that compressive stress is not applied to the narrow yoke portion at the bottom of the slot. Thereby, since the fall of a magnetic characteristic can be suppressed and the iron loss of a stator does not increase, the efficiency of an electric motor does not fall.

  The invention according to claim 5 is based on a distributed winding method in which, for example, magnetic flux is dispersed in each tooth portion by using the present invention for a stator of a concentrated winding motor in which a winding is directly wound around one tooth portion. By using the stator of a concentrated winding type motor in which a larger amount of magnetic flux is concentrated on one tooth portion and the magnetic flux density is higher than that of the stator of the electric motor, a decrease in magnetic characteristics is further suppressed.

  The invention according to claim 6 can reduce the compressive stress when the outer frame is fitted to the stator by using the compressor in which the stator of the motor is incorporated in the outer frame. A reduction in characteristics is suppressed, and a stator that does not reduce the efficiency of the motor can be obtained. Thereby, the energy efficiency for air conditioners and refrigerators driven by an electric motor can be increased.

  According to the seventh aspect of the present invention, the same effect as described above can be obtained by using the stator of an electric motor that is incorporated in an outer frame and mounted for in-vehicle use.

  The present invention relates to an electric motor including a stator having a plurality of teeth portions in the circumferential direction and an outer frame to which the stator contacts and fixes. Occurs when assembling the outer frame to the stator by providing a gap between the teeth base and the outer periphery of the stator fixed in contact with the outer frame to relieve stress in the vicinity of the outer periphery of the stator. The compressive stress strain can be absorbed, and the deterioration of the magnetic characteristics in the stator can be suppressed. Thereby, the iron loss which generate | occur | produces in a stator can be reduced, and it can come out that the fall of an electric motor efficiency is prevented.

  In addition, the gap portion is provided with a bridge portion that connects the stator tooth base of the stator to the outer periphery of the stator that is fixed in contact with the outer frame. It can be set as the stator of the electric motor which does not loosen and fall off.

  Further, as a method of preventing the stator outer peripheral portion from being permanently deformed and falling off the stator when the outer frame is fitted to the stator, the outer frame with the center of the stator inner diameter as the center of the axis can be used. The outer periphery of the stator is fixed by making the opening angle of the outer periphery of the stator fixed in contact with the opening equal to or wider than the opening angle of the gap provided to relieve stress in the vicinity of the outer periphery of the stator. The strength can be maintained without sinking into the part, and the stator can be prevented from loosening and falling off from the outer frame due to the elastic force of the outer periphery of the stator.

  In addition, the yoke portion of the stator (for example, the stator core portion between the slot bottom and the outer periphery of the stator) is prevented from coming into contact with the outer frame so that the magnetic flux density of the stator is very high. Compressive stress is not applied to the part. As a result, a decrease in magnetic characteristics can be prevented, and a decrease in motor efficiency can be prevented.

  In addition, it is possible to effectively suppress deterioration of magnetic characteristics due to compressive stress by applying to a stator of a concentrated winding type motor in which magnetic flux concentrates on a yoke part or a teeth part from a distributed winding type stator.

  Further, the present invention can be used for stators of all electric motors in which the outer frame is contact-fixed to the stator. In particular, the stators of electric motors mounted on compressors for air conditioners and refrigerators driven by electric motors, An excellent effect can be obtained by using it as a stator of an electric motor for vehicle use.

  Embodiments of the present invention will be described with reference to the drawings. The electric motor of FIG. 1 is a cross-sectional view of an electric motor in which the stator 1 is fixed in contact with the outer frame 7. In this case, as a method of contacting and fixing the stator 1 of the motor to the outer frame 7, a shrinking method in which the outer frame 7 is heated and fixed to the stator 1 is contacted, or the outer frame 7 is brought into contact with the stator 1 at a low temperature. The present invention can be applied to a cooling swallow method for fixing, a press-fitting method for press-fitting the outer frame 7 into the stator 1, and the like. It should be noted that the workability is improved and the stator 1 can be easily fixed to the outer frame by appropriately using a shrinking method, a cooling method, a press-fitting method, or the like. Moreover, as a material used for the outer frame 7 of the stator 1 of FIG. 1, it is iron, aluminum etc., for example, and does not ask | require a magnetic material and a nonmagnetic material.

  The stator 1 used in this embodiment of FIG. 1 is provided with an annular yoke portion 5, and six teeth portions 4 extend from the annular yoke portion 5 in the inner diameter direction of the stator 1, and the teeth portion 4 and the teeth portion. A slot 2 is formed between the four slots. The slot 2 is provided with a winding by a concentrated winding method in which the winding 3 is directly wound around the tooth portion 4 to form a three-phase four-pole. Note that an insulating material (resin bobbin, film, etc.) for insulating the winding 3 is used for the slot 2, but it is not shown. Moreover, in this embodiment, what has the same function on the structure is attached | subjected the same symbol.

  A plurality of notches 11 are provided on the outer periphery of the stator 1. By providing this notch 11, cooling between the outer frame 7 and the stator 1 can be performed. For example, in a compressor stator 1 used for an air conditioner or a refrigerator, a notch 11 provided on the outer periphery of the stator 1 is used as a gas passage through which refrigerant gas or the like flows. The outer frame 7 that is fixed in contact with the stator 1 is fixed in contact with the outer peripheral portion 9 of the stator where the teeth 8 of the stator 1 are located.

  FIG. 2 shows a partially enlarged view of each tooth portion 4 of the embodiment shown in FIG. An arrow 13 in the figure represents the flow of magnetic flux. As a magnetic flux path, magnetic flux from the narrow-width yoke portion 5 of the slot bottom portion 12 adjacent to and sandwiching the teeth portion 4 flows from the narrow-width yoke portion 5 of the slot bottom portion 12 where the magnetic flux concentrates and flows. . However, as can be seen from FIG. 2, it can be seen that the magnetic flux is not concentrated in the vicinity of the stator outer peripheral portion 9 where the teeth root 8 is located, and the magnetic flux density is relatively low.

  Therefore, when the stator 1 is contacted and fixed to the outer frame 7 and the magnetic characteristics are not deteriorated by the compressive stress applied to the stator 1, the stator outer peripheral portion 9 where the teeth root 8 of the stator 1 is located is provided. By making contact and fixation with the outer frame 7, it is possible to reduce the influence of the compressive stress on the magnetic characteristics. Thereby, the iron loss which generate | occur | produces in the stator 1 can be reduced, and it can come out that the fall of an electric motor efficiency is prevented.

  Further, a gap portion 10 is provided between the teeth root 8 and the stator outer peripheral portion 9 of the stator 1 to relieve stress in the vicinity of the stator outer peripheral portion 9. The gap portion 10 is provided as a through hole in the vicinity of the stator outer peripheral portion 9 so as to follow the axial direction of the stator 1. The shape of the gap 10 may be a long hole along the stator outer peripheral part 9 or a round hole.

  For example, as the shape of the through hole provided between the teeth base 8 and the stator outer peripheral portion 9 of the stator 1, magnetic flux concentrates on the yoke portion 5 of each slot bottom 12 as described above. The magnetic fluxes from the yoke portions 5 of the adjacent slot bottom portions 12 merge and flow into the teeth portion 4. Therefore, the shape of the magnetic flux flowing into the yoke portion 5 of each slot bottom 12 may be such that there is no hindrance. For example, FIG. 3 shows another embodiment different from that shown in FIG. By making the side Y1 facing the yoke part 5 side of the slot bottom part 12 shorter than the side Y2 facing the tooth part 4, the magnetic flux can flow without the shape of the gap 10a interfering with the magnetic path.

  In addition, a gap provided between the teeth base 8 and the outer periphery of the stator 1 fixed in contact with the outer frame 7 is generated, for example, when the stator 1 is fixed by shrinkage to the outer frame 7. It is possible to prevent the deterioration of magnetic characteristics due to the influence of compressive stress. However, depending on the fastening allowance between the stator 1 and the outer frame 7, the holding force between the outer frame 7 and the stator 1 may be reduced. This is because when the tightening margin is set large, the stator iron core between the gap portion of the stator 1 and the stator outer peripheral side sinks into the gap portion and loses elastic force to be permanently deformed.

  In such a case, as shown in FIG. 1 and FIG. 2, the teeth portion root 8 of the stator 1 is placed in the gap portion 10 provided between the teeth portion root 8 of the stator 1 and the stator outer peripheral portion 9. By providing the bridge portion 6 extending from the outer periphery 9 to the stator, the holding force between the outer frame 7 and the stator 1 can be maintained. In this case, the position of the bridge portion 6 across the gap portion 10 is set such that the substantially central portion of the gap portion 10 provided between the teeth root 8 and the stator outer peripheral portion 9 extends from the teeth root 8 to the stator outer peripheral portion 9. , And is provided at a substantially central portion of the gap 10 to prevent the compressive stress such as shrinkage of the stator 1 from being applied to the gap 10 in a biased manner. In addition, when there are a plurality of gap portions 10, a plurality of bridge portions 6 are provided so that compressive stress is applied evenly. Thereby, the compressive stress applied to the stator 1 by the outer frame 7 can be made uniform.

  Further, the width of the bridge portion 6 is preferably equal to or greater than the thickness of one sheet of the thin electromagnetic steel plate constituting the stator, and by making it narrower than the width of the teeth portion 4 of the stator 1, It is easy to provide the gap portion 10, and the stator outer peripheral portion 9 due to the compressive stress does not sink into the gap 10 and is permanently deformed.

  When viewed from the inner diameter of the stator 1 as shown in FIGS. 1 to 3, the opening angle θ1 of the stator outer peripheral portion 9 fixed in contact with the outer frame 7 around the center of the inner diameter of the stator 1 is By making the opening 10 the same as or wider than the opening angle θ2 of the gap 10, 10a between the teeth base 8 of the stator 1 and the stator outer periphery 9 that is fixed to the outer frame 7 in contact with the outer frame 7, When the frame 7 is fitted, it is possible to prevent the stator outer peripheral portion 9 of the gap portions 10 and 10a from sinking and being permanently deformed, and the stator 1 from falling off.

  Θ1 is a stator outer peripheral portion 9 which is fixed in contact with the outer frame 7 around the inner diameter center of the stator 1, and the outer frame 7 and the stator outer periphery where one tooth root 8 of the stator 1 is located. The portion 9 is a portion that is fixed in contact with the portion 9. Further, θ2 is a gap 10, 10a between the teeth base 8 of the stator 1 and the stator outer periphery 9 fixed in contact with the outer frame 7. In this case, the gap 10, provided in the teeth base 8, When there are a plurality of 10a, it is the opening angle of the gap located on the outermost side of the gap in the circumferential direction of the stator, and the side wall of the gap located on the outermost side of the gap around the teeth portion 4 of the stator 1 Is the maximum opening angle formed by the sides or points.

  Accordingly, the stator core portion between the outer peripheral portion 9 of the stator that is fixed in contact with the outer frame 7 and the outermost diameter of the gap portions 10 and 10a so that θ2 ≦ θ1 is depressed in the gap portions 10 and 10a. The elastic force is not lost, and the holding force between the outer frame 7 and the stator outer peripheral portion 9 does not decrease. Further, the width of the stator core between the outer peripheral portion 9 of the stator and the outermost diameter of the gaps 10 and 10a is equal to or greater than the thickness of one thin magnetic steel sheet having a laminated structure in the axial direction of the stator 1. Yes, it may be a width that can relieve the compressive stress, and may be provided, for example, about 0.25 mm to 3 mm.

  In the embodiment, the stator outer peripheral portion 14 where the slot bottom portion 12 is located is not fixed in contact with the outer frame 7. The slot bottom 12 has a large cross-sectional area of the slot 2 so that as many windings 3 as possible can be mounted in the slot 2 in order to improve the motor performance. From such a structure, the yoke portion 5 between the slot bottom portion 12 and the stator outer peripheral portion 14 inevitably has a narrow width. When this narrow width is fixed in contact with the outer frame 7, the influence of the compressive stress is very large. This deteriorates the magnetic characteristics as compared with the case where the stator outer peripheral portion 9 where the tooth root 8 is located is fixed to the outer frame 7 in contact.

  As described above with reference to FIG. 2, the magnetic fluxes flowing from the narrow-width yoke portion 5 of the slot bottom portion 12 join at the stator tooth portion base 8 and flow into the teeth portion 4. In this case, the magnetic flux flowing from the vicinity of the tooth base 8 to the tooth portion 4 toward the inner diameter side of the stator 1 is increased, but in the vicinity of the stator outer peripheral portion 9 fixed in contact with the outer frame 7 where the tooth base 8 is located. The magnetic flux is not so high.

  From this, the magnetic flux path passes through the narrow width yoke portion 5 of the slot bottom portion 12 and flows from the vicinity of the teeth portion 8 to the teeth portion 4, so that the stator core in the vicinity of the stator outer periphery 9 of the teeth portion root 8 is provided. Is relatively less affected by magnetic flux. Therefore, the stator outer peripheral portion 9 of the teeth base 8 with little deterioration in magnetic properties due to compressive stress is fixed in contact with the outer frame 7. On the other hand, the stator outer peripheral portion 14 of the yoke portion 5 having a narrow width at the slot bottom portion 12 that is greatly affected by the magnetic characteristics due to the compressive stress is not in contact with the outer frame 7.

  As can be seen from the flow of the magnetic flux, for example, the winding 3 is directly wound around one tooth portion 4 from the stator 1 in which the magnetic flux is distributed to the plurality of tooth portions 4 by the distributed winding method, and the magnetic flux is concentrated. By providing the gap portions 10 and 10a between the teeth base 8 and the stator outer peripheral portion 9 in the concentrated winding type stator 1, it is possible to more effectively suppress the deterioration of the magnetic properties and to reduce the iron loss. It can be prevented from increasing. Thereby, the fall of the efficiency of an electric motor can be prevented. In particular, the tooth portion 4 in which the winding 3 is concentrated winding has a wider tooth width than the distributed winding type stator, and therefore the stator core portion in the vicinity of the stator outer peripheral portion 9 where the teeth portion root 8 is located is also provided. Since the magnetic flux density in this part is wide and relatively low, the position where the air gaps 10 and 10a for relaxing the compressive stress are provided is optimal.

  FIG. 4 shows a case where a gap 10 is provided between the tooth base 8 of the stator and the outer peripheral portion 9 of the stator that is fixed in contact with the outer frame 7 to reduce the compressive stress (practical product). This is a comparison of the efficiency of the electric motor with the case (conventional product). The presence or absence of the gap 10 changes the influence on the magnetic characteristics, and the ratio of the iron loss in the motor performance changes. In particular, the effect is noticeable at low speed where the ratio of iron loss is large. In FIG. 5, as in FIG. 4, the motor loss due to the presence or absence of the gap 10 is separated and shown in a bar graph. As in FIG. 4, it can be seen that the iron loss is reduced. FIG. 4 shows a case where the rotation speed is 1800 rpm and the loss at the rated load is separated.

  As described above, the gaps 10 and 10a are provided between the teeth base 8 of the stator and the outer periphery 9 of the stator, and the reduction of the efficiency of the motor is reduced by relaxing the compressive stress in the vicinity of the stator outer periphery 9. Therefore, it is possible to prevent the deterioration of magnetic properties by using the stator of the motor on the outer frame for all outer frame motors that are fixed in contact with the outer frame by methods such as shrinking, cooling, and press fitting. It is possible to prevent the efficiency from decreasing. In particular, it can be used as a stator of an electric motor that is hardly affected by the compressive stress of the outer frame by being used for a stator of an electric motor mounted on a compressor for an air conditioner or a refrigerator, or an electric motor for an on-vehicle use. .

The cross-sectional view at the time of fixing the stator of an electric motor to the outer frame in embodiment. The elements on larger scale of the space | gap part located between the stator teeth part base in FIG. 1, and a stator outer peripheral part. The figure which showed another embodiment of the space | gap part. The graph which compared the motor efficiency at the time of making the stator of an electric motor contact and fix to an outer frame. The loss comparison of the stator of the electric motor demonstrated in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Stator, 2 ... Slot, 3 ... Winding, 4 ... Teeth part, 5 ... Yoke part, 6 ... Bridge part, 7 ... Outer frame, 8 ··· teeth portion base, 9,14 ··· stator outer periphery portion, 10, 10a ··· gap portion, ········································ ..Contact fixed opening angle between outer frame and stator outer periphery, θ2... Gap opening angle.

Claims (7)

In an electric motor comprising a stator having a plurality of teeth portions in the circumferential direction, and an outer frame for contacting and fixing the stator,
The outer periphery of the stator where the teeth base is located is fixed to the outer frame in contact,
Between the teeth base and the stator outer periphery fixed in contact with the outer frame,
A stator for an electric motor, wherein a gap is provided to relieve stress in the vicinity of the outer periphery of the stator. The stator of the electric motor according to claim 1, wherein a bridge portion is provided in the gap portion to connect the outer periphery of the stator contacted and fixed to the outer frame from the base of the tooth portion. Is the opening angle of the outer periphery of the stator centered on the inner diameter center of the stator in contact with and fixed to the outer frame the same as the opening angle of the gap provided to relieve stress in the vicinity of the outer periphery of the stator? The stator of the electric motor according to claim 1, wherein the stator is wider than that. The stator outer periphery where the teeth portion root is located is fixed in contact with the outer frame, and the stator outer periphery where the slot bottom provided in the stator is positioned is not in contact with the outer frame. The stator of the electric motor according to any one of claims 1 to 3. 5. The motor fixing according to claim 1, wherein a winding by a concentrated winding method in which a direct winding is wound is mounted on a teeth portion of the stator of the electric motor. Child. The stator for an electric motor according to any one of claims 1 to 5, which is mounted on a compressor for an air conditioner or a refrigerator driven by the electric motor. The stator for an electric motor according to any one of claims 1 to 5, wherein the stator is mounted as a stator for an in-vehicle electric motor.

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