JP5370529B2 - Electric compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reliably reduce deformation of an assembled housing independently of distortion of stator core sheets. <P>SOLUTION: A stator core 32 comprising a laminate of circumferentially circular stator core sheets is fixed in a motor housing 15 with at least part of an outer circumference of the stator core 32 in contact with an inner surface of the motor housing 15. Specifically, stator core sheets die-punched from an electromagnetic steel sheet are laminated by 180&deg; turns in reference to the rolling direction of the electromagnetic steel sheet, and portions of the punched stator core sheets with smaller differences in stator core outside diameter dimension from the die are set as fixed positions and portions with larger differences in the direction of increasing outside diameter dimension are set as non-fixed positions. <P>COPYRIGHT: (C)2012,JPO&amp;INPIT

Description

  The present invention relates to an electric compressor.

  FIG. 6 shows an example of a stator 100 in a motor, and the stator 100 is fixed in a cylindrical housing 150. The stator core 110 in the stator 100 is configured by laminating a plurality of stator core sheets. In FIG. 6, windings and the like are omitted.

  As shown in FIG. 7, a general electromagnetic steel sheet strip 160 is rolled to a predetermined thickness, and the stator core sheet 111 is punched from the electromagnetic steel sheet strip 160 using a mold. Then, a plurality of stator core sheets 111 are laminated to form a stator core 110.

  On the other hand, as shown in FIG. 8, there is a thickness deviation in the direction perpendicular to the rolling direction in the electromagnetic steel sheet strip 160. Therefore, in the stator core 110 that requires a squareness, the punched stator core sheet 111 is rotated and stacked (so-called “rolling”).

  A copper wire is wound around the teeth 110a (see FIG. 6) of the stator core 110 to insulate the stator 100 of the motor. The stator 100 is fixed to the housing 150 by shrink fitting as shown in FIG. In FIG. 6, the stator 100 is shown as being fixed all around by the housing 150.

  Patent Document 1 discloses a technique for manufacturing a stator core in a perfect circle. Specifically, an ellipse that extends in a direction perpendicular to the rolling direction and contracts in the rolling direction is corrected to a perfect circle by correcting the mold. In Patent Document 2, the stator is fixed by a plurality of protrusions on the inner wall of the housing.

Japanese Patent Laid-Open No. 10-24333 JP 2006-299834 A

  However, when the electromagnetic steel sheet strip 160 is punched with a mold, distortion occurs in the stator core sheet as shown in FIG. That is, FIG. 9 shows the outer periphery mold contour of the stator core sheet and the punched stator core sheet outer periphery contour. The outer periphery mold contour of the stator core sheet is a perfect circle, but the stamped stator core sheet outer periphery contour is an ellipse. (Even if the outer peripheral mold of the stator core sheet is a circle, the actual stator core sheet is oval). Specifically, in a stator core sheet having a circular outer periphery, as shown in FIG. 9, the outer diameter dimension increases in the rolling direction of the electromagnetic steel sheet, and the outer diameter dimension decreases in the direction orthogonal to the rolling direction. The outer diameter may be small in the rolling direction, and the outer diameter may be large in the direction orthogonal to the rolling direction.

  Since the distortion after punching the electromagnetic steel sheet strip 160 is different between lots, it is important for the manufacturer of the stator core 110 to manage the outer diameter of the stator core sheet 111. It was necessary to adjust the mold to ensure the process capability.

  In addition, a part of the outer peripheral portion of the housing 150 may be flattened and a sensor may be attached to the flat portion. However, since the stator 100 is fixed due to the influence of the outer peripheral strain of the stator core 110, the flatness of the flat processed portion is deteriorated. If the sensor is attached to such a flat portion having deteriorated flatness, the sensitivity of the sensor may not be fulfilled due to poor sensitivity. For this reason, after the stator 100 is fixed to the housing 150, it has been unavoidable to perform planar processing after taking measures to prevent foreign matter from entering the housing 150.

  Furthermore, in the 18-slot stator core sheet as shown in FIG. 6, for example, when the stator core 110 rolled 60 ° as shown in FIG. As the stator core 110 is made of a perfect circle, the contact area between the inner periphery of the shrink-fit housing 150 and the outer periphery of the stator core 110 is smaller than that of the housing 150 during high load operation. There is a possibility that the stator 100 may rotate because the fixing is lost to the torque generated by the motor.

  The present invention has been made under such a background, and an object thereof is to reduce the deformation of the housing after assembly with high reliability without affecting the distortion of the stator core sheet.

  The invention according to claim 1 is an electric compressor having a compression mechanism inside and an annular stator core fastened inside a cylindrical motor housing, wherein the stator core is formed by laminating a plurality of elliptical stator core sheets. The stator core is fixed in the motor housing in a state where at least a part of the outer periphery thereof is in contact with the inner surface of the motor housing, and includes an intersection with a long axis in the outer peripheral contour of the stator core sheet. The range includes an unfixed position with respect to the motor housing, and further includes a point having angles of 45 °, 135 °, 225 °, and 315 ° around the center with respect to the intersection with the long axis in the outer peripheral contour of the stator core sheet. Is a fixed position with respect to the motor housing.

  According to a second aspect of the present invention, in the electric compressor according to the first aspect, the stator core is stacked by rotating 180 degrees around the center with respect to the intersection with the long axis in the outer peripheral contour of the stator core sheet. May be formed.

  According to the present invention, the reliability is high without affecting the distortion of the stator core sheet, and the deformation of the housing after assembly can be reduced.

The schematic sectional drawing which shows the stator fixed to the housing in this embodiment. The disassembled perspective view which shows rolling of a stator core sheet. An explanatory view showing distortion of a stator core sheet. Explanatory drawing for determining the fixed / non-fixed boundary. The schematic sectional drawing which shows the stator fixed to the housing of another example. The schematic sectional drawing which shows the stator fixed to the housing for demonstrating background art. The top view for demonstrating the stator core sheet | seat punched out from an electromagnetic steel plate strip. The perspective view which shows the plate | board thickness deviation of an electromagnetic steel plate strip. An explanatory view showing distortion of a stator core sheet. Sectional drawing in the state which has arrange | positioned the laminated stator core sheet | seat in the housing. The schematic sectional drawing embodied in the hermetic compressor using the motor which has the stator fixed to the housing by the fixing method in this embodiment.

Hereinafter, an embodiment of a hermetic electric compressor embodying the present invention will be described with reference to the drawings. The compressor has a compression mechanism inside.
First, the configuration of the electric compressor 10 will be described. As shown in FIG. 11, a sealed housing 11 constituting the electric compressor 10 is a bottomed horizontal cylindrical housing formed by forging aluminum, for example. The main body 12 and a front housing 13 joined and fixed to an opening edge of the front side (right side in FIG. 11) of the housing main body 12 are configured. The housing body 12 includes a compressor housing 14 on the front side, a motor housing 15 integrally formed at the rear end portion of the compressor housing 14, and a rear housing 16 integrally formed at the rear end portion of the motor housing 15. It is comprised by.

  A scroll-type compression mechanism 17 is accommodated in the compressor housing 14. The compression mechanism portion 17 is fixedly fitted and fixed to the inner peripheral surface of the opening on the front side of the compressor housing 14 and the base plate 18 fitted and fixed to the step portion of the inner peripheral surface 14a of the compressor housing 14. The scroll member 19 and the orbiting scroll member 20 accommodated between the substrate 18 and the fixed scroll member 19 are configured. A compression chamber 21 formed by the fixed scroll member 19 and the orbiting scroll member 20 passes through a suction hole 18 a formed in the substrate 18 from a suction chamber 22 formed on the back side of the substrate 18 inside the compressor housing 14. Refrigerant gas is sucked and compressed. The compressed refrigerant gas is discharged into a discharge chamber 23 in the front housing 13 from a discharge hole 19 a provided in the fixed scroll member 19.

  The front housing 13 is formed with an outlet 13a for supplying compressed refrigerant gas to an external cooling circuit. An inlet 16a for introducing refrigerant gas from an external cooling circuit is formed in the suction chamber 22 on the outer peripheral surface of the rear housing 16.

  A stator 31 is fitted and fixed to the inner peripheral surface of the motor housing 15 constituting the electric motor M. The stator 31 includes an iron stator core 32 and a winding 33 wound around a slot 32a (see FIG. 1 described later) formed on the inner peripheral side of the stator core 32. An annular stator core 32 is fastened inside the cylindrical motor housing 15. Between the boss portion 16b integrally formed on the inner bottom surface of the rear housing 16 and the boss portion 18b integrally formed on the back surface of the substrate 18, a rotating shaft 28 is rotatable via bearings 29 and 30. It is supported. An eccentric pin 34 provided at the tip of the rotary shaft 28 is connected to a boss 20a integrally formed on the back surface of the orbiting scroll member 20 via a bearing. A rotor 35 is fitted and fixed to the outer peripheral surface of the rotary shaft 28. Moreover, a part of outer peripheral part of the motor housing 15 is planar processed, and the inverter 50 is attached to the planar part 15a.

  Therefore, when an alternating current is applied to the winding 33 by an energization mechanism (not shown), the rotating shaft 28 is rotated by the electromagnetic induction action of the stator 31 and the rotor 35, and the eccentric pin 34 is swung, so that the turning The scroll member 20 is turned in a state where rotation is prevented. As a result, the refrigerant gas is compressed by the compression mechanism 17 described above.

Next, the configuration of the main part of the present invention will be described.
In FIG. 1, the schematic cross section of the stator side member of the motor in this embodiment is shown. In FIG. 1, a stator 31 is disposed in the motor housing 15. The stator core 32 in the stator 31 is configured by stacking stator core sheets 32b obtained by punching out electromagnetic steel strips as shown in FIG. That is, as described with reference to FIG. 7, the electromagnetic steel sheet strip 160 is rolled to a predetermined thickness, and the stator core sheet 32 b is punched from the electromagnetic steel sheet band 160 using a mold, and a plurality of stator core sheets are provided. The sheets are stacked to form the stator core 32. The stator core 32 has a circular outer peripheral shape.

  In FIG. 1, a slot 32 a is formed on the inner peripheral surface of the laminated stator core 32. In FIG. 1, the number of slots of the stator core 32 is “18”. In FIG. 1, windings and the like are omitted.

  As shown in FIG. 2, as a stacked structure of the stator core sheets 32 b in the stator core 32, the stator core sheets 32 b are rotated and rotated by 180 ° with respect to the rolling direction of the steel sheet. Thus, as described in FIG. 8, there is a thickness deviation in the direction perpendicular to the rolling direction in the electromagnetic steel strip 160, but the stator core sheet 32b is stacked vertically by rotating and stacking the stator core sheet 32b. can do. In addition, variations in the height of the stator core 32 after lamination can be reduced.

The stator core 32 having a laminated structure will be described.
When the outer periphery of the stator core sheet 32b is punched from the electromagnetic steel strip 160 using a circular mold, as shown in FIG. 3, even if the outer peripheral mold contour of the stator core sheet in the mold is a perfect circle, The outer contour of the stator core sheet or the stator core sheet that is further annealed after punching becomes an ellipse. In particular, in the present embodiment, an elliptical shape is shown in which the long axis is in the steel plate rolling direction and the short axis is in the direction perpendicular to the steel plate rolling direction.

  In FIG. 3, when the angle θ with respect to the steel plate rolling direction is about 45 °, about 135 °, about 225 °, and about 315 °, the stamped stator core sheet outer peripheral contour (ellipse) and the outer peripheral mold contour of the stator core sheet 32b (Circles) intersect. Therefore, the portion where the angle θ on the outer periphery of the stator core sheet 32b is about 45 °, about 135 °, about 225 °, and about 315 ° is the portion of the stamped stator core sheet 32b with respect to the outer diameter dimension for the stator core sheet in the mold. This is a portion where the difference in outer diameter dimension δ (variation) is small.

In this way, it can be seen that the punched portion having an angle of approximately 45 °, approximately 135 °, approximately 225 °, and approximately 315 ° with the rolling direction is not affected by the distortion or is extremely small.
FIG. 4 shows a tolerance added to the outer diameter of the stator core sheet in FIG.

  In FIG. 4, line A is a stator core sheet outer diameter tolerance median contour, and specifically, a perfect circle having a diameter of A mm. Line B is a stator core seat outer diameter tolerance upper limit contour and is a perfect circle of diameter A + amm (tolerance), and line C is a stator core seat outer diameter tolerance lower limit contour and is a true diameter A−amm (tolerance). It is a circle. Thus, the line B is the circle with the largest tolerance for the outer diameter dimension for the stator core sheet in the mold, and the line C is the circle with the smallest tolerance for the outer diameter dimension for the stator core sheet in the mold.

  In FIG. 4, line D is an ellipse representing the outer peripheral shape of the stamped stator core sheet 32 b (the outer peripheral contour of the stator core sheet formed into an ellipse). Specifically, taking a general steel sheet strip having a thickness of 0.35 mm as an example, when the outer periphery of the stator is punched with a circular mold, a strain of about 0.05% of the diameter is rolled on the steel sheet. And the direction perpendicular to the rolling direction. When 0.05% strain occurs in a stator core sheet having a diameter of Amm, the diameter is A + 0.0005 Amm in the rolling direction, and the diameter is A−0.0005 Amm in the direction perpendicular to the rolling direction. Therefore, in the ellipse indicated by line D in FIG. 4, the length of the major axis in the rolling direction is A + 0.0005 Amm, and the length of the minor axis in the direction orthogonal to the rolling direction is A−0.0005 Amm. The center of the ellipse indicated by the line D coincides with the ideal center of the perfect circle indicated by the line A. In this embodiment, 0.0005A> a.

In this way, FIG. 4 illustrates the case where the stator core sheet has a diameter of Amm, the outer diameter tolerance of the stator core sheet is ± amm, and the strain amount is 0.05%.
Here, the intersection points of the perfect circle indicated by the line B and the ellipse indicated by the line D are Pi1, Pi4, Pi5 and Pi8. Further, the intersections of the perfect circle indicated by the line C and the ellipse indicated by the line D are Pi2, Pi3, Pi6 and Pi7. The intersection points Pi1, Pi2, Pi3, Pi4, Pi5, Pi6, Pi7, Pi8 are respectively θ1, θ2, θ3, θ4, θ5, θ6, θ7, θ8 as the angles θ with respect to the steel sheet rolling direction. 3 and 4, the elliptical shape of the stator core 32 is drawn with more emphasis than actual.

  In consideration of this, in FIG. 1, stator core fixing protrusions 41 a, 41 b, 41 c, and 41 d are provided on the inner surface of the motor housing 15. The stator core fixing projections 41a, 41b, 41c, and 41d are in contact with the outer peripheral surface of the stator core 32 at the front end surfaces. That is, the stator core 32 is fixed in the motor housing 15 so that at least a part of the outer periphery of the stator core 32 and the inner surface of the motor housing 15 are in contact with each other.

  Here, the side surfaces (rising edges) of the stator core fixing protrusions 41a, 41b, 41c, and 41d are determined as follows. With respect to the rolling direction of the steel sheet, the side angles of the first stator core fixing protrusion 41a are θ1 and θ2 in FIG. Similarly, the side angles of the second stator core fixing protrusion 41b are θ3 and θ4 in FIG. The angles of the side surfaces of the third stator core fixing projection 41c are θ5 and θ6 in FIG. Regarding the fourth stator core fixing projection 41d, the angles of the side surfaces thereof are θ7 and θ8 in FIG.

  In this way, the fixing range of the stator core 32 in the motor housing 15 is set so that a portion where the difference δ of the outer diameter dimension of the stator core sheet 32b punched with respect to the outer diameter dimension for the stator core sheet in the mold is small is set as the fixing position. With respect to the rolling direction of the steel sheet, it is between θ1 and θ2, between θ3 and θ4, between θ5 and θ6, and between θ7 and θ8. Further, in order to place a portion having a large difference in the direction in which the outer diameter dimension is increased (difference in the outer diameter dimension of the stator core sheet 32b punched out with respect to the outer diameter dimension for the stator core sheet in the mold) in a non-fixed position, the motor housing 15, the non-fixed range of the stator core 32 is set between θ8 and θ1, between θ4 and θ5, and between θ2 and θ3, and between θ6 and θ7, based on the rolling direction of the steel sheet.

  Thus, the fixed ranges (θ1 ≦ θ ≦ θ2, θ3 ≦ θ ≦ θ4, θ5 ≦ θ ≦ θ6, θ7 ≦ θ ≦ θ8) vary depending on the tolerance of the outer diameter of the stator core 32, and are shown in FIGS. 4B and 4C. What is necessary is just to obtain | require an intersection by solving the expression of a circle | round | yen and the ellipse of D with simultaneous equations, respectively, and reflecting it in the protrusion design of the inner wall of the motor housing 15 of FIG. That is, a circle having the maximum and minimum tolerances for the outer diameter dimension of the stator core sheet in the mold (B and C in FIG. 4) and an ellipse whose center is the same as the center of the circle in the outer diameter dimension of the stator core sheet 32b (in FIG. 4). The intersections Pi1 to Pi8 with D) are defined as boundaries between the fixed position and the non-fixed position.

  Conventionally, since the distortion of the electromagnetic steel sheet strip 160 after die punching varies between lots, it is important for the manufacturer of the stator core 110 to manage the outer diameter dimension of the stator core sheet 111. It was necessary to adjust the mold to ensure the process capability. On the other hand, in this embodiment, regardless of the amount of strain between the electromagnetic steel strip bands, the portion where the difference δ in the outer diameter dimension of the stator core sheet 32b is small is set as the fixing position when fixing the motor housing 15 inside. Accordingly, the influence of the distortion of the stator core sheet 32b is eliminated, and the reliability is high, and the adjustment of the mold accompanying the management of the outer diameter of the stator core sheet 32b by the mold becomes unnecessary.

  Further, in FIG. 1, a part of the outer peripheral portion of the motor housing 15 is flattened, and the inverter 50 is attached to the flat portion. At this time, even if there is an outer periphery distortion of the stator core 32, the flatness of the flat processed portion does not deteriorate when the stator 31 is fixed. That is, if the inverter 50 is attached to the flat surface portion 15a having deteriorated flatness, the fixing failure of the inverter 50 may occur. In the present embodiment, this can be avoided. As a result, after the stator 31 is fixed to the motor housing 15, it is not necessary to perform planar processing after taking measures to prevent foreign matter from entering the motor housing 15. That is, the stator core is fixed in the housing by fixing the portion where the difference δ in the outer diameter of the stator core sheet is small in the housing regardless of the amount of distortion between the electromagnetic steel strip lots. Later, that is, the deformation of the housing after assembly is reduced (the flatness of the housing flat processing portion for mounting the inverter 50 is not deteriorated even after the stator is fixed), and it is not necessary to perform the flat processing after the stator is fixed.

  Furthermore, in the related art, in an 18-slot stator core sheet as shown in FIG. 6, for example, when a stator core rolled 60 ° as shown in FIG. Since the layers are rotated and rotated by 60 °, the contact area between the inner periphery of the shrink-fit housing 150 and the outer periphery of the stator core 110 becomes smaller than that when the stator core 110 is made of a perfect circle, and the housing is operated during high load operation. There is a possibility that the fixing of 150 loses the torque generated by the motor and the stator rotates. On the other hand, in the present embodiment, regardless of the amount of strain between the electrical steel sheet strip lots, the rolling angle is determined so that the parts having a small difference (variation) δ in the outer diameter of the stator core overlap, and the parts are determined. A stable contact area can be obtained since the fixing position is fixed to the housing. Therefore, in a rolled stator core with a rolled angle of 180 °, it is possible to secure a stable contact area between the inner periphery of the housing and the outer periphery of the stator core when being fixed in the housing, so that the fixing force in the housing is lost to the torque generated by the motor. Therefore, there is no risk that the stator (stator core) will rotate, and the reliability is high.

According to the above embodiment, the following effects can be obtained.
(1) As a method of fixing the stator core 32 in the motor housing 15 with at least a part of the outer periphery of the stator core 32 and the inner surface of the motor housing 15 in contact with each other, as described with reference to FIGS. A portion where the difference δ of the outer diameter dimension of the stator core sheet 32b punched out with respect to the outer diameter dimension for the stator core sheet is small is a fixed position (θ1 ≦ θ ≦ θ2, θ3 ≦ θ ≦ θ4, θ5 ≦ θ ≦ θ6 in FIG. θ7 ≦ θ ≦ θ8), and a portion (θ8 <θ <θ1, θ4 <θ <θ5 in FIG. 1) where the difference δ is large in the direction of increasing the outer diameter is set as an unfixed position. Therefore, it is possible to provide a stator core fixing method that is highly reliable without affecting the distortion of the stator core sheet 32b and that hardly deforms the housing after assembly. Further, in the hermetic compressor using this fixing method, fixing failure when fixing the inverter 50 to the motor housing 15 can be prevented.

  (2) As described with reference to FIGS. 1 and 4, the outer diameter dimension for the stator core sheet in the mold represents the circle having the maximum tolerance (B in FIG. 4) and the outer peripheral shape of the stamped stator core sheet 32 b. When the boundary between the fixed position and the non-fixed position is determined from the intersection points Pi1, Pi4, Pi5, and Pi8 with the ellipse (D in FIG. 4), the design considering the outer diameter tolerance of the stator core sheet can be performed.

  (3) As described with reference to FIGS. 1 and 4, the circle having the largest tolerance for the outer diameter dimension for the stator core sheet in the mold (B in FIG. 4) and the tolerance for the outer diameter dimension for the stator core sheet in the mold. Is obtained by solving the equations of the circle having the smallest diameter (C in FIG. 4) and the ellipse (D in FIG. 4) representing the outer peripheral shape of the stamped stator core sheet 32b by simultaneous equations, and obtaining the intersection thereof. Therefore, the dimensional tolerance management of the fixed position of the motor housing 15 can be easily designed.

  (4) As described with reference to FIGS. 1 and 3, the fixing of the stator core 32 is affected at a portion where the difference δ of the outer diameter of the stator core sheet 32b punched out with respect to the outer diameter of the stator core sheet in the mold is large. The parts that are not present (θ2 <θ <θ3, θ6 <θ <θ7 in FIG. 1) are set as non-fixed positions. Therefore, the hermetic housing 11 can be reduced in weight and the manufacturing cost can be reduced. In addition, when the motor is used in a hermetic electric compressor as in the present embodiment, the inverter 50 is positioned on the outer peripheral surface of the motor housing 15 at a non-fixed position between the stator core fixing protrusions 41a and 41b. It is arranged at the corresponding position. Accordingly, during operation of the compressor, when the refrigerant gas is introduced into the suction chamber 22 from the inlet 16a, the stator core fixing projections 41a and 41b can be passed between them, so that the inverter 50 can be efficiently cooled. .

The embodiment is not limited to the above, and may be embodied as follows, for example.
Focusing on the fact that the outer diameter distortion in the rolling direction contributes to the housing deformation, as shown in FIG. 5 instead of FIG. 1, the fixing range of the stator core 32 in the motor housing 15 is defined as θ1 to It may be between θ4 and between θ5 and θ8, and only the outer diameter strained portion in the rolling direction may not be fixed.

  Further, although the case where the number of slots 32a of the stator core 32 is “18” has been described, the number of slots is not limited to this and may be other slots.

  DESCRIPTION OF SYMBOLS 11 ... Housing, 31 ... Stator, 32 ... Stator core, 32b ... Stator core sheet, 41a ... 1st stator core fixing protrusion, 41b ... 2nd stator core fixing protrusion, 41c ... 3rd stator core fixing protrusion, 41d ... 1st 4 stator core fixing protrusions, δ...

Claims (2)

In an electric compressor having a compression mechanism inside and an annular stator core fastened inside a cylindrical motor housing,
The stator core is formed by laminating a plurality of elliptical stator core sheets,
The stator core is fixed in the motor housing in a state where at least a part of the outer periphery thereof is in contact with the inner surface of the motor housing, and a range including an intersection with the long axis in the outer peripheral contour of the stator core sheet is defined with respect to the motor housing. A non-fixed position is set, and a range including points with angles of 45 °, 135 °, 225 °, and 315 ° around the center with respect to the intersection with the long axis in the outer peripheral contour of the stator core sheet is fixed to the motor housing. An electric compressor characterized by being positioned. 2. The electric compressor according to claim 1, wherein the stator core is formed by rotating and laminating 180 degrees around the center with respect to an intersection with a long axis in an outer peripheral contour of the stator core sheet.