Compressor

Abstract

A compressor comprises: a compressor housing including a body part (2a) having a cylindrical shape; a compression part that is disposed inside the compressor housing and compresses a refrigerant; and a motor disposed inside the compressor housing. The motor includes a rotor and a stator core (23) disposed on an outer circumferential side of the rotor. The body part (2a) includes a first welded part (19) to which the body part (2a) is joined along the axial direction of a rotation shaft of the motor. The stator core (23) includes, in the circumferential direction of the stator core (23), a plurality of large-diameter parts (37) that come into contact with an inner circumferential surface of the body part (2a), and a plurality of non-large-diameter parts (38) in which the distance (R2) from the center (O) of the stator core (23) to an outer circumferential surface is shorter than that of the large-diameter parts (37). As viewed from the axial direction of the rotation shaft, the non-large-diameter parts (38) are disposed on a first straight line (L1) passing through the center (O) of the stator core (23) and the first welded part (19) along the radial direction of the stator core (23).

Description

Compressor

[0001] The present invention relates to a compressor.

[0002] As a compressor, there is known one in which the outer peripheral surface of the stator core of a motor is fixed to the inner peripheral surface of a compressor housing in which the motor is disposed inside. This type of compressor has a structure in which a plurality of protruding portions protruding radially outward of the stator core are provided on the outer peripheral portion of the stator core (Patent Document 1). In this structure, by bringing each protruding portion of the stator core into contact with the inner peripheral surface of the compressor housing, the contact range (contact surface) in contact with the inner peripheral surface of the compressor housing in the circumferential direction of the stator core is reduced, and when the stator core is fixed in the compressor housing, the compressive stress applied from the compressor housing to the stator core is reduced, and deformation of the stator core is suppressed.

[0003] Japanese Patent Application Laid-Open No. 2011-55576, Patent No. 7168883

[0004] By the way, generally, the compressor housing of a compressor is formed into a cylindrical shape by bending a rectangular iron plate, and a welded portion for joining both ends of the iron plate is provided, whereby a cylindrical body portion is formed (Patent Document 2). The body portion of the compressor housing formed in this way has a problem that the inner diameter on the straight line passing through the welded portion is large in the radial direction of the body portion, the inner diameter in the direction orthogonal to this straight line is small, and the inner peripheral surface of the body portion tends to be substantially elliptical in the circumferential direction of the body portion.

[0005] When the stator core is fixed to the inner peripheral surface of the body portion that has become substantially elliptical, a gap occurs between the inner peripheral surface of the body portion and the outer peripheral surface of the stator core in the radial direction along the straight line passing through the welded portion among the radial directions of the body portion, and there is a possibility that the holding force of the inner peripheral surface of the body portion for holding the outer peripheral surface of the stator core may decrease. In particular, when the contact surface between the inner peripheral surface of the body portion of the compressor housing and the stator core is reduced as in the structure of Patent Document 1, the decrease in the holding force of the inner peripheral surface of the body portion for holding the outer peripheral surface of the stator core becomes remarkable.

[0006] The disclosed technology has been made in view of the above, and an object thereof is to provide a compressor capable of suppressing a decrease in the holding force of the inner peripheral surface of the body portion of the compressor housing for holding the outer peripheral surface of the stator core.

[0007] One embodiment of a compressor disclosed in this application comprises a compressor housing having a cylindrical body, a compression unit disposed inside the compressor housing for compressing a refrigerant, and a motor disposed inside the compressor housing. The motor has a rotor and a stator core disposed on the outer circumference of the rotor. The body has a first welded joint where the body is joined along the axial direction of the motor's rotation axis. The stator core has a plurality of large-diameter portions in the circumferential direction of the stator core that are in contact with the inner circumferential surface of the body, and a plurality of non-large-diameter portions where the distance from the center of the stator core to the outer circumferential surface is smaller than that of the large-diameter portions. When viewed from the axial direction of the rotation axis, the non-large-diameter portions are arranged along the radial direction of the stator core on a first straight line passing through the center of the stator core and the first welded joint.

[0008] According to one embodiment of the compressor disclosed in this application, the reduction in the holding force by which the inner circumferential surface of the compressor housing holds the outer circumferential surface of the stator core can be suppressed.

[0009] Figure 1 is a longitudinal cross-sectional view showing the compressor of the embodiment. Figure 2 is a transverse cross-sectional view showing the three-phase motor of the compressor of the embodiment. Figure 3 is a plan view showing the stator of the three-phase motor in the embodiment. Figure 4 is a plan view showing the stator core in the embodiment. Figure 5 is a side view showing the first and second welds formed on the body of the container in the embodiment. Figure 6 is a transverse cross-sectional view illustrating the deformation that occurs when forming the body of the container in the embodiment. Figure 7 is a transverse cross-sectional view illustrating the main part of the stator core in the embodiment. Figure 8 is a transverse cross-sectional view showing an enlarged portion of Figure 7 to illustrate the first straight line in the embodiment. Figure 9 is a diagram showing the distribution of compressive stress occurring in the stator core in the embodiment. Figure 10 is a diagram showing the distribution of compressive stress occurring in the stator core in a comparative example. Figure 11 is a transverse cross-sectional view showing a modified stator core.

[0010] The following describes in detail, with reference to the drawings, an embodiment of the compressor disclosed in this application. However, the following embodiment does not limit the compressor disclosed in this application.

[0011] Figure 1 is a longitudinal cross-sectional view showing a compressor according to the embodiment. As shown in Figure 1, the compressor 1 is a so-called rotary compressor and comprises a container 2 as the compressor housing, a shaft 3 as the rotating shaft, a compression unit 5, and a three-phase motor 6.

[0012] The container 2 has a cylindrical body (main shell) 2a, a cup-shaped upper part (top shell) 2b, and a cup-shaped lower part (bottom shell) 2c. The body 2a, upper part 2b, and lower part 2c of the container 2 are made of metal material, and the upper part 2b is welded to the upper end of the body 2a, and the lower part 2c is welded to the lower end of the body 2a, thereby forming a sealed internal space 7. The internal space 7 is generally cylindrical. When the container 2 is placed vertically on a horizontal plane, it is constructed such that the central axis of the cylinder forming the internal space 7 is parallel to the vertical direction. The container 2 has an oil reservoir 8 formed in the lower part of the internal space 7. The oil reservoir 8 stores refrigerant oil 8a, which is a lubricating oil for lubricating the compression part 5. The container 2 is connected to an intake pipe 11, which serves as an intake part for drawing in refrigerant, and a discharge pipe 12, which serves as a discharge part for discharging compressed refrigerant. The shaft 3, which serves as the axis of rotation, is formed in a rod shape and is positioned in the internal space 7 of the container 2 such that one end is placed in the oil reservoir 8. The shaft 3 is supported by the container 2 so as to be rotatable about the central axis of the cylinder that makes up the internal space 7. By rotating, the shaft 3 supplies the refrigerant oil 8a stored in the oil reservoir 8 to the compression unit 5.

[0013] The compression section 5 is located at the bottom of the internal space 7 and above the oil reservoir 8. The compressor 1 further comprises an upper muffler cover 14 and a lower muffler cover 15. The upper muffler cover 14 is located above the compression section 5 in the internal space 7. The upper muffler cover 14 forms an upper muffler chamber 16 inside. The lower muffler cover 15 is located below the compression section 5 in the internal space 7 and above the oil reservoir 8. The lower muffler cover 15 forms a lower muffler chamber 17 inside. The lower muffler chamber 17 communicates with the upper muffler chamber 16 via a connecting passage (not shown) formed in the compression section 5. A compressed refrigerant discharge hole 18 is formed between the upper muffler cover 14 and the shaft 3, and the upper muffler chamber 16 communicates with the internal space 7 via the compressed refrigerant discharge hole 18.

[0014] The compression unit 5 compresses the refrigerant supplied from the intake pipe 11 as the shaft 3 rotates, and supplies the compressed refrigerant to the upper muffler chamber 16 and the lower muffler chamber 17. The refrigerant is compatible with the refrigerant oil 8a. The three-phase motor 6 is located above the compression unit 5 in the internal space 7.

[0015] Figure 2 is a cross-sectional view showing the three-phase motor 6 of the compressor 1 of the embodiment. As shown in Figures 1 and 2, the three-phase motor 6 comprises a rotor 21 and a stator 22. The rotor 21 is formed in a cylindrical shape by stacking a plurality of metal plates (not shown) and is integrated by a plurality of rivets 9. A shaft 3 is inserted through the center of the rotor 21, and the rotor 21 is fixed to the shaft 3. The rotor 21 has six slit-shaped magnet embedding holes 10a formed so as to form the sides of a hexagon with the shaft 3 as the center. Each magnet embedding hole 10a is formed at a predetermined interval in the circumferential direction of the rotor 21. Plate-shaped permanent magnets 10b are embedded in the magnet embedding holes 10a.

[0016] The stator 22 is generally cylindrical in shape and is positioned to surround the outer circumference of the rotor 21. The stator 22 comprises an annular stator core 23, an upper insulator 24 and a lower insulator 25, and a plurality of windings 46 (see Figure 1). The stator 22 and the container 2 are welded together by a plurality of second welds 20, which will be described later, formed at intervals in the circumferential direction of the stator 22.

[0017] The upper insulator 24 is fixed to the upper end of the stator core 23. The lower insulator 25 is fixed to the lower end of the stator core 23. As shown in Figures 1 and 2, an insulating film 26 is inserted into the stator core 23 along the inner circumferential surface of the slots between the stator core teeth 32-1 to 32-9, which will be described later, and the stator core 23 and the windings 46 are insulated by the insulating film 26. The insulating film 26 is made of a resin material such as polyethylene terephthalate (PET) or polyethylene naphthalate (PEN). The upper insulator 24 and the lower insulator 25 are made of a resin material and are insulating members that insulate the stator core 23 and the windings 46.

[0018] (Stator Structure) Figure 3 is a plan view showing the stator 22 of a three-phase motor 6 in an embodiment. As shown in Figure 3, windings 46, which are electric wires, are wound around each of the multiple stator core teeth 32-1 to 32-9 in the stator core 23, which will be described later. Each of the stator core teeth 32-1 to 32-9 has a winding portion 45 formed by each winding 46. The three-phase motor 6 in this embodiment is a concentrated winding type motor with 6 poles and 9 slots (see Figure 2). The multiple windings 46 include multiple U-phase windings 46-U1 to 46-U3, multiple V-phase windings 46-V1 to 46-V3, and multiple W-phase windings 46-W1 to 46-W3. Furthermore, in the stator 22, the neutral wires drawn from each winding section 45 and bundled together are covered with insulating tubing and inserted into the gaps between adjacent winding sections 45 in the circumferential direction of the stator 22 (the direction of rotation of the rotor 21) (see Figure 2).

[0019] Figure 4 is a plan view showing the stator core 23 in an embodiment. As shown in Figure 4, the stator core 23 comprises an annular yoke portion 31 and a plurality of stator core teeth portions 32-1 to 32-9 (also called stator core teeth portions 32) that serve as a winding drum portion, and is formed by laminating a plurality of metal plates. The metal plates are made of a soft magnetic material such as silicon steel plate.

[0020] The yoke portion 31 is formed in a generally cylindrical shape. Of the multiple stator core tooth portions 32-1 to 32-9, the first stator core tooth portion 32-1 is formed in a generally columnar shape. One end of the first stator core tooth portion 32-1 is formed continuously on the inner circumference side of the yoke portion 31, that is, it is formed to protrude from the inner circumferential surface of the yoke portion 31 toward the central axis of the stator core 23. The stator core tooth portions 32-2 to 32-9, other than the first stator core tooth portion 32-1, are also formed in a generally columnar shape, similar to the first stator core tooth portion 32-1, and protrude from the inner circumferential surface of the yoke portion 31 toward the central axis of the stator core 23. Furthermore, the multiple stator core tooth portions 32-1 to 32-9 are formed on the inner circumferential surface of the yoke portion 31, arranged at equal intervals of 40 degrees in the circumferential direction of the yoke portion 31. Hereinafter, the multiple stator core teeth portions 32-1 to 32-9 of the stator core 23 will be referred to as the stator core teeth portion 32.

[0021] Furthermore, as shown in Figure 4, the outer circumferential surface of the stator core 23 is provided with six first recesses 35 and three second recesses 36 extending axially along the stator core 23, at positions corresponding to each stator core tooth portion 32 in the circumferential direction of the stator core 23, serving as grooves through which the refrigerant oil 8a and refrigerant in the container 2 pass. In the circumferential direction of the stator core 23, two first recesses 35 are positioned between adjacent second recesses 36. The three second recesses 36 are arranged at equal intervals in the circumferential direction of the stator core 23. In addition, notched grooves 36a are formed in the three second recesses 36 for positioning and attaching the upper insulator 24 and the lower insulator 25 relative to the stator core 23. The main parts of the stator core 23 in this embodiment will be described later.

[0022] (Characteristic configuration of the compressor) Next, the characteristic configuration of the compressor 1 of the embodiment will be described. The characteristics of the embodiment include the shape of the stator core 23 in the three-phase motor 6, and the arrangement of the stator core 23 in the circumferential direction of the body portion 2a that was deformed during the manufacturing process of the container 2.

[0023] (Deformation of the body) Figure 5 is a side view showing the first welded portion 19 and the second welded portion 20 formed on the body portion 2a of the container 2 in the embodiment. Figure 6 is a cross-sectional view illustrating the deformation that occurs when forming the body portion 2a of the container 2 in the embodiment.

[0024] In the manufacturing process of container 2, a metal plate is formed into a cylindrical shape by bending, and the ends of the metal plate are joined together by seam welding to form a first welded portion 19, which is a seam weld. As shown in Figure 5, the first welded portion 19 extends along the axial direction of the shaft 3 of the three-phase motor 6 installed inside container 2, and the metal plate forming the body portion 2a is joined to it. Note that the first welded portion 19 is not limited to seam welding and may be formed by other welding methods such as laser welding or gas welding.

[0025] Next, the body portion 2a, on which the first welded portion 19 is provided, is subjected to a diameter expansion process to enlarge it to a predetermined inner diameter from the inner circumference side of the body portion 2a. At this time, because the mechanical strength near the first welded portion 19 in the circumferential direction of the body portion 2a is higher than that of other parts in the circumferential direction of the body portion 2a, the diameter expansion is not uniformly carried out over the entire circumference of the body portion 2a.

[0026] As a result, as shown in Figure 6, in the cross-section of the body portion 2a, it deforms outward in the first direction connecting the first weld 19 and the center of the body portion 2a, and inward in the second direction perpendicular to the first direction, so that the inner circumferential surface of the body portion 2a tends to become a substantially elliptical shape with a major axis along the first direction. When a stator core 23 formed with a constant outer diameter is fitted into such a body portion 2a, a gap is created between the inner circumferential surface of the body portion 2a and the outer circumferential surface of the stator core 23 in the major axis direction (first direction) where the first weld 19 is located, which reduces the holding force of the inner circumferential surface of the body portion 2a in holding the outer circumferential surface of the stator core 23.

[0027] Therefore, in this embodiment, the outer diameter of the stator core 23 is partially varied in the circumferential direction of the stator core 23, and the outer circumferential surface of the stator core 23 is positioned at a predetermined location relative to the inner circumferential surface of the body portion 2a, thereby suppressing the reduction in the holding force mentioned above.

[0028] Furthermore, in the manufacturing process of the compressor 1 of this embodiment, the stator 22 is temporarily fixed to the body portion 2a of the container 2 by shrink-fitting the body portion 2a of the container 2 onto the stator 22. As will be described later, in the stator core 23 of this embodiment, by reducing the area in the circumferential direction of the body portion 2a where the inner surface of the body portion 2a and the outer surface of the stator core 23 are in contact, the compressive stress generated in the stator core 23 by the external force applied from the body portion 2a that is shrink-fitted onto the stator 22 can be reduced.

[0029] As described above, the stator 22 is temporarily fixed within the body portion 2a, and then, as shown in Figure 5, is spot-welded to the body portion 2a and fixed by the second weld portion 20, which is a spot weld. In this embodiment, multiple second weld portions 20 are arranged at equal intervals in the circumferential direction of the stator core 23, as shown in Figures 2 and 7. As will be described in detail later, the arrangement of multiple second weld portions 20 at equal intervals suppresses deformation of the stator core 23 into which the body portion 2a is shrink-fitted. In addition, as shown in Figure 5, multiple second weld portions 20 are provided at intervals in the axial direction of the stator 22 (axial direction of the shaft 3). Note that the second weld portions 20 are not limited to spot welding and may be formed by other welding methods such as laser welding or gas welding.

[0030] (Large-diameter and non-large-diameter portions of the stator core) Figure 7 is a cross-sectional view illustrating the main part of the stator core 23 in the embodiment, showing the contact state between the stator core 23 and the body portion 2a of the container 2. Figure 8 is a cross-sectional view showing an enlarged portion of Figure 7 to illustrate the first straight line L1 in the embodiment.

[0031] As shown in Figures 4 and 7, the stator core 23 of the stator 22 has a plurality of large-diameter portions 37 that are in contact with the inner circumferential surface of the body portion 2a, and a plurality of non-large-diameter portions 38 whose distance from the center O of the stator core 23 to the outer circumferential surface is smaller than that of the large-diameter portions 37.

[0032] The non-large diameter portion 38 has a plurality of small diameter portions 39 along the circumferential direction of the stator core 23, where the distance R2 from the center O of the stator core 23 to the outer surface is smaller than the distance R1 from the center O of the stator core 23 to the outer surface of the large diameter portion 37, and a first recess 35 and a second recess 36 through which the refrigerant oil 8a passes. The first recess 35 and the second recess 36 are formed recessed toward the center O of the stator core 23 than the outer surface of the small diameter portion 39, so that the distance from the center O of the stator core 23 to the outer surface is smaller than that of the small diameter portion 39.

[0033] Furthermore, each large-diameter portion 37 is fitted to the inner circumferential surface of the body portion 2a of the container 2 by intermediate fitting. By intermediate fitting the three large-diameter portions 37 to the body portion 2a, when the body portion 2a is shrink-fitted to the large-diameter portions 37 of the stator core 23, the portion of the stator core 23 that receives external force from the body portion 2a is reduced and the external force applied from the body portion 2a is mitigated, compared to the case where the entire outer circumferential surface of the stator core 23 is in contact with the inner circumferential surface of the body portion 2a. Each small-diameter portion 39 is gap-fitted to the inner circumferential surface of the body portion 2a such that a gap G is provided between the stator core 23 and the inner circumferential surface of the body portion 2a in the radial direction of the stator core 23.

[0034] In this embodiment, three large-diameter portions 37 are arranged in the circumferential direction of the stator core 23 at equal intervals of 120 degrees in the central angle around the center O of the stator core 23. In this embodiment, six small-diameter portions 39 are arranged in the circumferential direction of the stator core 23, two on each side of the large-diameter portions 37. The large-diameter portions 37 and small-diameter portions 39 refer to a part of the circumferential direction on the outer surface of the annular yoke portion 31 of the stator core 23.

[0035] As shown in Figure 4, in the circumferential direction of the stator core 23, the circumferential length W1 of the large-diameter portion 37 and the circumferential length W2 of the small-diameter portion 39 along the outer surface of the stator core 23 are formed to be approximately the same. Each large-diameter portion 37 and each small-diameter portion 39 is set to have a central angle of approximately 20 degrees around the center O of the stator core 23.

[0036] In the circumferential direction of the stator core 23, the small-diameter range, which is the sum of the circumferential lengths W2 of the multiple small-diameter portions 39 along the outer circumferential surface of the stator core 23, is larger than the large-diameter range, which is the sum of the circumferential lengths W1 of the multiple large-diameter portions 37. That is, the sum of the circumferential lengths W2 of the six small-diameter portions 39, 6W2, is larger than the sum of the circumferential lengths W1 of the three large-diameter portions 37, 3W1. As a result, in the circumferential direction of the stator core 23, the large-diameter range in which the outer circumferential surface of the stator core 23 is in contact with the inner circumferential surface of the container 2 is reduced, and the external force applied from the container 2 to the stator core 23 during shrink-fitting can be appropriately reduced.

[0037] As shown in Figures 7 and 8, when R1 is the distance (large radius) from the center O of the stator core 23, which is the rotation center of the three-phase motor 6, to the outer surface of the large-diameter portion 37, and R2 is the distance (small radius) from the center O to the outer surface of the small-diameter portion 39, the relationship R1 > R2 is satisfied. Furthermore, in the body portion 2a which is deformed into a roughly elliptical shape, when R3a is the maximum distance (maximum radius of the body portion) from the center O to the inner surface of the body portion 2a along the major axis of the roughly elliptical shape, and R3b is the minimum distance (minimum radius of the body portion) from the center O to the inner surface of the body portion 2a along the minor axis of the roughly elliptical shape, the relationship R3a > R3b > R2 is satisfied. The distance R1 in the large-diameter portion 37 is formed to a size that is an intermediate fit with respect to the minimum distance R3b of the body portion 2a. Furthermore, each small-diameter portion 39 that is fitted into the inner circumferential surface of the body portion 2a of the container 2 has a gap G (= R3a - R2, or R3b - R2) between the outer circumferential surface of the small-diameter portion 39 and the inner circumferential surface of the body portion 2a that is greater than 0 and less than or equal to 250 [μm]. The gap G is set, for example, to 50 [μm] ≤ G ≤ 250 [μm].

[0038] In other words, when the body portion 2a of the container 2 is shrink-fitted onto the stator core 23, the contact portion where the outer circumferential surface of the stator core 23 contacts the inner circumferential surface of the body portion 2a is the large-diameter portion 37, and the non-contact portion where the outer circumferential surface of the stator core 23 does not contact the inner circumferential surface of the body portion 2a is the non-large-diameter portion 38 (for example, the small-diameter portion 39). The large-diameter portion 37 is a contact portion for temporarily fixing the stator core 23 inside the body portion 2a during the manufacturing process of the compressor 1, and it is sufficient that at least two large-diameter portions 37 are provided at appropriate positions in the circumferential direction of the stator core 23 for temporary fixing. That is, in the radial direction of the stator core 23, the portion formed to be large in order to bring the stator core 23 into contact with the body portion 2a is the large-diameter portion 37, and the portion formed to be small in order to prevent the stator core 23 from contacting the body portion 2a is the non-large-diameter portion 38. When a 9-slot stator core 23 is used as in the embodiment, it is preferable that three large-diameter portions 37 are provided as in the embodiment. This configuration allows the large-diameter portions 37 to be arranged at equal intervals in the circumferential direction of the stator core 23.

[0039] (First and Second Straight Lines) In the compressor 1 of the embodiment, when viewed from the axial direction of the shaft 3, the non-large diameter portion 38 is positioned on a first straight line L1 that passes through the center O of the stator core 23 and the first welded portion 19 along the radial direction of the stator core 23. That is, the stator core 23 is positioned and provided with respect to the circumferential direction of the body portion 2a such that either the small diameter portion 39, the first recess 35, or the second recess 36, which is the non-large diameter portion 38, is positioned on the first straight line L1.

[0040] In the approximately elliptical deformed body portion 2a, the inner diameter of the body portion 2a is maximum in the direction of the major axis of the approximately ellipse where the first straight line L1 is located, and the inner diameter of the body portion 2a is minimum in the direction of the minor axis of the approximately ellipse. For this reason, the large-diameter portion 37 that contacts the approximately elliptical deformed body portion 2a is positioned away from the first straight line L1 in the circumferential direction of the stator core 23 so as not to be positioned on the first straight line L1 where the inner diameter of the body portion 2a is maximum along the major axis. Consequently, the large-diameter portion 37 is avoided from being positioned on the first straight line L1 where the inner diameter of the body portion 2a is maximum in the approximately elliptical deformed body portion 2a. In other words, the large-diameter portion 37 contacts the body portion 2a at a position where the inner diameter of the body portion 2a is smaller than the inner diameter on the first straight line L1. This prevents gaps from forming between the outer circumferential surface of each large-diameter portion 37 that is in contact with the body portion 2a and the inner circumferential surface of the body portion 2a, unlike when the large-diameter portions 37 are arranged on the first straight line L1. As a result, a decrease in the holding force by which the inner circumferential surface of the body portion 2a holds the outer circumferential surface of the stator core 23 (the outer circumferential surface of each large-diameter portion 37) can be suppressed.

[0041] Furthermore, in the compressor 1 of this embodiment, the small-diameter portion 39 is arranged on the first straight line L1. As a result, the small-diameter portion 39 is arranged in the longitudinal direction of the substantially elliptical deformed body portion 2a, so compared to the structure in which the first recess 35 and the second recess 36 are arranged on the first straight line L1, the body portion 2a is less likely to come into contact with the small-diameter portion 39 when the body portion 2a is shrink-fitted to the stator core 23, and the compressive stress generated in the stator core 23 due to the small-diameter portion 39 coming into contact with the body portion 2a can be reduced. As a result, deformation of the stator core 23 can be suppressed, the magnetic balance in the circumferential direction of the stator core 23 is made uniform, and the decrease in efficiency of the three-phase motor 6 can be suppressed. Note that it is sufficient to have at least one small-diameter portion 39 arranged on the first straight line L1 to obtain the effect of reducing the compressive stress generated in the stator core 23.

[0042] Furthermore, in the compressor 1 of the embodiment, when viewed from the axial direction of the shaft 3, the large-diameter portion 37 is positioned on a second straight line L2 that passes through the center O of the stator core 23 and is perpendicular to the first straight line L1 in the radial direction of the stator core 23. In the substantially elliptical deformed body portion 2a, the inner diameter of the body portion 2a is minimized in the direction of the minor axis of the substantially ellipse where the second straight line L2 is located. Therefore, by positioning the large-diameter portion 37 on the second straight line L2, the large-diameter portion 37 contacts the body portion 2a at the position where the inner diameter of the body portion 2a is minimized in the substantially elliptical deformed body portion 2a, thereby appropriately securing the aforementioned holding force.

[0043] The first welded portion 19 formed on the body portion 2a has a width dimension along the circumferential direction of the body portion 2a on the outer surface of the body portion 2a, for example, about 5 mm to 10 mm. Therefore, as shown in Figure 8, in the circumferential direction of the body portion 2a, there is a first straight line L1 between the first straight line L1 passing through one end 19a of the first welded portion 19 and the first straight line L1 passing through the other end 19b of the first welded portion 19, and there are multiple first straight lines L1 depending on the width dimension of the first welded portion 19.

[0044] Therefore, in the embodiment, when viewed from the axial direction of the shaft 3, the non-large-diameter portion 38 being disposed on the first straight line L1 means that the stator core 23 is disposed in the body portion 2a such that all of the plurality of first straight lines L1 existing as described above pass through the non-large-diameter portion 38. That is, the stator core 23 is disposed in the body portion 2a such that the entire width dimension of the first welded portion 19 faces the non-large-diameter portion 38.

[0045] Also, regarding the second straight line L2 orthogonal to the first straight line L1, although there are also a plurality of them as in the case of the first straight line L1, for the large-diameter portion 37 that contacts the body portion 2a for temporary fixing, it is sufficient that the large-diameter portion 37 is disposed on at least one of the plurality of second straight lines L2 when viewed from the axial direction of the shaft 3. From the viewpoint of enhancing the contact state between the body portion 2a and the large-diameter portion 37, it is desirable that the stator core 23 is disposed in the body portion 2a such that all of the plurality of second straight lines L2 pass through the large-diameter portion 37.

[0046] (Position of the second welded portion) Each of the plurality of second welded portions 20 where the stator core 23 and the body portion 2a are spot welded is disposed on any one of the plurality of non-large-diameter portions 38 excluding the first straight line L1. In other words, each of the plurality of second welded portions 20 is not disposed on the first straight line L1. In the embodiment, in the stator core 23 in which each large-diameter portion 37 is fitted into the body portion 2a by shrink fitting, the second welded portion 20 is disposed only on the small-diameter portion 39.

[0047] By welding the non-large-diameter portion 38 in this way, a tensile force that pulls the stator core 23 outward in the radial direction of the body portion 2a acts on the second welded portion 20, and tensile stress is generated in the stator core 23. By canceling the compressive stress generated in the stator core 23 where the large-diameter portion 37 contacts the body portion 2a, deformation of the stator core 23 can be suppressed. Further, in the embodiment, since the plurality of second welded portions 20 are arranged at equal intervals in the circumferential direction of the stator core 23, the effect of canceling the compressive stress as described above is obtained evenly in the circumferential direction of the stator core 23, and the effect of suppressing deformation of the stator core 23 is enhanced. [[ID=,11]]

[0048] In addition, since the second welding portion 20 is not arranged on the first straight line L1, it is possible to avoid welding at a position on the first straight line L1 where the gap between the inner surface of the cylindrical portion 2a and the outer peripheral surface of the stator core 23 becomes maximum in the circumferential direction of the cylindrical portion 2a. For this reason, when welding is performed on the first straight line L1 where the gap becomes maximum, the spatter that scatters during welding becomes large, and the problem of spatter adhering to the inside of the cylindrical portion 2a can be avoided.

[0049] The second welding portion 20 is not mainly for holding the stator core 23 in the cylindrical portion 2a, but for restricting the movement of the stator core 23. Therefore, it may be provided on at least one of the plurality of small-diameter portions 39. In other words, by providing at least one second welding portion 20 in any of the non-large-diameter portions 38 located between the large-diameter portions 37, it acts so as to cancel the compressive stress generated by the contact of the large-diameter portion 37 with the cylindrical portion 2a, and thus the effect of suppressing the deformation of the stator core 23 can be obtained.

[0050] (Reinforcement portion of non-large-diameter portion) As shown in FIG. 7, caulking portions 28A as reinforcement portions for increasing the mechanical strength of the non-large-diameter portion 38 are provided in the vicinity of each of the plurality of second welding portions 20 on the stator core 23. In other words, the caulking portion 28A is provided on each of the small-diameter portions 39 included in the non-large-diameter portion 38 and joined to the cylindrical portion 2a by the second welding portion 20, and is located in the vicinity of the second welding portion 20 in the circumferential and radial directions of the small-diameter portion 39, that is, in the vicinity of the outer peripheral surface of the small-diameter portion 39. The caulking portion 28A is formed along the stacking direction (axial direction of the shaft 3) on the plurality of metal plates stacked so as to form the stator core 23, and joins the plurality of metal plates together.

[0051] The crimped portion 28A undergoes plastic deformation during formation and becomes less deformable due to work hardening, thereby increasing the mechanical strength of the small-diameter portion 39 where the second welded portion 20 is formed. This suppresses deformation of the stator core 23 due to compressive stress generated in the stator core 23. The reinforcing portion is not limited to the crimped portion 28A; for example, a part of the small-diameter portion 39, i.e., a part of the metal plate, may be formed from a highly rigid reinforcing material, although this is not shown in the figures. Furthermore, an enlarged portion (not shown) may be formed as a reinforcing portion in a part of the small-diameter portion 39 to make the width dimension of the small-diameter portion 39 along the circumferential direction of the stator core 23 larger than the width dimension of the large-diameter portion 37, thereby increasing the rigidity of the small-diameter portion 39.

[0052] In addition, there are voids (not shown) inside the crimped portion 28A in the stacking direction of the multiple metal plates, and these voids also act as insulating spaces that insulate the heat transmitted to the stator core 23 during welding of the body portion 2a and the small diameter portion 39 of the container 2. This prevents the insulating film 26 placed in the slots between the stator core teeth portions 32 from melting due to the heat generated during welding of the second weld portion 20.

[0053] (Reinforcement of large diameter section) Each of the multiple large diameter sections 37 of the stator core 23 is provided with a crimped section 28B, which serves as a reinforcement to increase the mechanical strength of the large diameter section 37, similar to the crimped section 28A of the small diameter section 39. The crimped section 28B provided on the large diameter section 37 is located in the center of the large diameter section 37 in both the circumferential and radial directions. In the crimped section 28B of the large diameter section 37, similar to the crimped section 28A of the small diameter section 39, it is formed along the lamination direction on multiple metal plates laminated to constitute the stator core 23, and connects the multiple metal plates to each other. In the crimped section 28B of the large diameter section 37, similar to the crimped section 28A of the small diameter section 39, the mechanical strength of the small diameter section 39 is increased by the effect of work hardening, which makes it difficult to deform. This makes it possible to suppress deformation of the stator core 23 due to compressive stress generated in the stator core 23. Furthermore, the reinforcing portion of the large-diameter portion 37 is not limited to the crimped portion 28B, and although not shown, for example, a part of the large-diameter portion 37, i.e., a part of the metal plate, may be formed from a reinforcing material with high rigidity.

[0054] (Compressive stress applied to the stator core) The compressive stress applied to the stator core 23 of the embodiment from the body portion 2a of the container 2 will be explained in comparison with the stator core 123 of the comparative example.

[0055] Figure 9 shows the distribution of compressive stress generated in the stator core 23 in the embodiment. Figure 10 shows the distribution of compressive stress generated in the stator core 123 in the comparative example. In Figures 9 and 10, as the negative values ​​shown in the figures decrease, that is, as the color approaches white from black, the compressive stress applied from the body portion 2a to the stator core 23 increases.

[0056] In the comparative example stator core 123, the same parts as in the embodiment stator core 23 are given the same reference numerals as in the embodiment and their descriptions are omitted. The comparative example stator core 123 has nine outer peripheral portions 137 formed with a constant radius (the distance between the center O of the stator core 123 and the outer peripheral surface of the outer peripheral portion 137 is constant), and between each outer peripheral portion 137, there is a recess, either a first recess 35 or a second recess 36, similar to the embodiment. The outer peripheral portions 137 in the comparative example are formed to be inter-fitted into the body portion 2a, similar to the large diameter portion 37 in the embodiment.

[0057] Therefore, the stator core 23 of the embodiment has a structure in which it contacts the body portion 2a at three locations, which are the three large-diameter portions 37, while the stator core 123 of the comparative example has a structure in which it contacts the body portion 2a at nine locations, which are the nine outer peripheral portions 137.

[0058] Comparing Figure 9 and Figure 10, in the comparative example stator core 123 shown in Figure 10, the compressive stress generated in the annular yoke portion 31, where the nine outer peripheral portions 137 contact the body portion 2a, is relatively large, while the compressive stress generated in the stator core teeth portion 32 is relatively small.

[0059] On the other hand, in the stator core 23 of the embodiment shown in Figure 9, the compressive stress generated on the outer circumference of the three large-diameter portions 37 that contact the body portion 2a is about the same as that of the outer circumference portion 137 in the comparative example, but the compressive stress generated on the inner circumference of the large-diameter portions 37 and the non-large-diameter portions 38 is about the same as that of the stator core teeth portion 32 in the comparative example. In other words, in the stator core 23 of the embodiment, the compressive stress generated in the yoke portion 31 excluding the outer circumference of the large-diameter portions 37 and in the stator core teeth portion 32 is about the same as the compressive stress generated in the stator core teeth portion 32 in the comparative example. Therefore, the stator core 23 of the embodiment can reduce the compressive stress generated in the yoke portion 31 due to external forces applied from the body portion 2a.

[0060] Therefore, in the embodiment, the stator core 23 experiences reduced compressive strain due to compressive stress, thus suppressing deformation of the stator core 23 and reducing distortion in the air gap between the stator core 23 and the rotor 21. As a result, the magnetic balance of the stator core 23 in the circumferential direction is made uniform, and the decrease in efficiency of the three-phase motor 6 is suppressed.

[0061] (Effects of the Embodiment) As described above, in the compressor 1 of the embodiment, the stator core 23 of the three-phase motor 6 has a plurality of large-diameter portions 37 that contact the inner circumferential surface of the body portion 2a of the container 2 in the circumferential direction of the stator core 23, and a plurality of non-large-diameter portions 38 whose distance R2 from the center O of the stator core 23 to the outer circumferential surface is smaller than that of the large-diameter portions 37. When viewed from the axial direction of the shaft 3, the non-large-diameter portions 38 are arranged along the radial direction of the stator core 23 on a first straight line L1 that passes through the center O of the stator core 23 and the first weld portion 19. Therefore, the large-diameter portions 37 are not positioned on the first straight line L1 where the inner diameter of the body portion 2a is maximum in the substantially elliptical body portion 2a, and the large-diameter portions 37 contact the body portion 2a at a position where the inner diameter of the body portion 2a is smaller than the inner diameter on the first straight line L1. This prevents a gap from forming between the outer circumferential surface of each large-diameter portion 37 that is in contact with the body portion 2a and the inner circumferential surface of the body portion 2a, unlike when the large-diameter portions 37 are arranged on the first straight line L1. As a result, a decrease in the holding force by which the inner circumferential surface of the body portion 2a holds the outer circumferential surface of the stator core 23 (the outer circumferential surface of each large-diameter portion 37) can be suppressed.

[0062] Furthermore, in the compressor 1 of the embodiment, the stator core 23 has a plurality of second welds 20 where the inner circumferential surface of the body portion 2a and the outer circumferential surface of the stator core 23 are joined, and each of the plurality of second welds 20 is located in one of the plurality of non-large diameter portions 38, excluding the first straight line L1. When the non-large diameter portions 38 are welded in this way, a tensile force acts on the second welds 20, pulling the stator core 23 radially outward from the body portion 2a, and tensile stress is generated in the stator core 23. This tensile stress cancels out the compressive stress generated in the stator core 23 where the large diameter portion 37 is in contact with the body portion 2a, thereby suppressing deformation of the stator core 23. In addition, by not arranging the second welds 20 on the first straight line L1, it is possible to avoid welding at a position on the first straight line L1 where the gap between the inner surface of the body portion 2a and the outer circumferential surface of the stator core 23 is maximum in the circumferential direction of the body portion 2a. Therefore, when welding is performed on the first straight line L1 where the gap is largest, the amount of spatter scattered during welding becomes large, and the problem of spatter adhering to the inside of the body 2a can be avoided.

[0063] Furthermore, in the compressor 1 of the embodiment, the stator core 23 is provided with crimping portions 28A near each of the multiple second welds 20 to increase the mechanical strength of the non-large diameter portions 38 (small diameter portions 39). This suppresses deformation of the stator core 23 due to compressive stress generated in the stator core 23. In addition, the voids inside the crimping portions 28A also act as insulating spaces that insulate the heat transmitted to the stator core 23 during welding of the body portion 2a and the small diameter portion 39. As a result, the insulating film 26 placed in the slots between the stator core teeth portions 32 is prevented from melting due to the heat generated during welding of the second welds 20.

[0064] Furthermore, in the compressor 1 of the embodiment, the multiple second welds 20 are arranged at equal intervals in the circumferential direction of the stator core 23. As a result, the effect of the tensile stress generated in the second welds 20 canceling out the compressive stress generated in the stator core 23 is obtained uniformly in the circumferential direction of the stator core 23, thereby enhancing the effect of suppressing deformation of the stator core 23.

[0065] Furthermore, in the compressor 1 of this embodiment, when viewed from the axial direction of the shaft 3, the large-diameter portion 37 is positioned on a second straight line L2 that passes through the center O of the stator core 23 and is perpendicular to the first straight line L1 in the radial direction of the stator core 23. As a result, in the substantially elliptical-shaped body portion 2a, the large-diameter portion 37 contacts the body portion 2a at the position where the inner diameter of the body portion 2a is smallest, so that the holding force that the inner circumferential surface of the body portion 2a holds the outer circumferential surface of the stator core 23 (the outer circumferential surface of each large-diameter portion 37) can be appropriately secured.

[0066] Furthermore, in the compressor 1 of the embodiment, each of the multiple large-diameter portions 37 of the stator core 23 is provided with a crimping portion 28B that increases the mechanical strength of the large-diameter portion 37. This makes it possible to suppress deformation of the stator core 23 due to compressive stress generated in the stator core 23.

[0067] Furthermore, in the compressor 1 of the embodiment, the stator core 23 has at least one small-diameter portion 39 arranged on the first straight line L1. As a result, the small-diameter portion 39 is arranged in the longitudinal direction of the substantially elliptical deformed body portion 2a, so compared to a structure in which the first recess 35 and the second recess 36 are arranged on the first straight line L1, the body portion 2a is less likely to come into contact with the small-diameter portion 39 when the body portion 2a is shrink-fitted to the stator core 23, and the compressive stress generated in the stator core 23 due to the small-diameter portion 39 coming into contact with the body portion 2a can be reduced. As a result, deformation of the stator core 23 can be suppressed, the magnetic balance in the circumferential direction of the stator core 23 is made uniform, and the decrease in efficiency of the three-phase motor 6 can be suppressed.

[0068] The following describes modified examples with reference to the drawings. In the modified examples, the same components and structural parts as in the embodiment are denoted by the same reference numerals as in the embodiment, and their descriptions are omitted. The stator core of the modified example differs from that of the embodiment in the shape of the non-large diameter section.

[0069] (Modified Example) Figure 11 is a cross-sectional view showing a modified stator core 123. As shown in Figure 11, the modified stator core 51 has a plurality of non-large diameter portions 52, the distance from the center O of the stator core 123 to the outer circumferential surface being smaller than the large diameter portion 37. The non-large diameter portions 52 are formed along the circumferential direction of the stator core 123 at a constant distance R5. The distance R5 of the non-large diameter portions 52 is formed to be approximately the same as, or smaller than, the distance R2 of the small diameter portion 39 in the embodiment. In the comparative example, as in the embodiment, the non-large diameter portions 52 are arranged on a first straight line L1, and the large diameter portion 37 is arranged on a second straight line L2.

[0070] Furthermore, a second welded portion 20 is formed by spot welding the body portion 2a to one of the multiple non-large diameter portions 52. The gap between the outer circumferential surfaces of the multiple non-large diameter portions 52 and the inner circumferential surface of the body portion 2a functions as a groove through which the refrigerant oil 8a and refrigerant in the container 2 pass. Also, for example, a notched groove 36a is formed on the outer circumferential surface of one of the multiple non-large diameter portions 52 for positioning and attaching the upper insulator 24 and the lower insulator 25 relative to the stator core 23.

[0071] In the modified example, by arranging the non-large diameter portion 52 on the first straight line L1, similar to the embodiment, the large diameter portion 37 is not positioned on the first straight line L1 where the inner diameter of the body portion 2a is maximum in the substantially elliptical deformed body portion 2a, and is positioned at a location where the inner diameter of the body portion 2a is smaller than the inner diameter on the first straight line L1. This prevents a gap from forming between the outer circumferential surface of each large diameter portion 37 that is in contact with the body portion 2a and the inner circumferential surface of the body portion 2a. Therefore, a decrease in the holding force of the inner circumferential surface of the body portion 2a in holding the outer circumferential surface of the stator core 23 can be suppressed.

[0072] 1 Compressor 2 Vessel (compressor housing) 2a Body 3 Shaft (rotating shaft) 5 Compression section 6 Three-phase motor 19 First welded section 20 Second welded section 21 Rotor 22 Stator 23 Stator core 28A Crimped section (reinforcement section) 28B Crimped section (reinforcement section) 35 First recess (groove section) 36 Second recess (groove section) 37 Large diameter section 38 Non-large diameter section 39 Small diameter section L1 First straight line L2 Second straight line O Center R1, R2 Distance

Claims

1. A compressor comprising: a compressor housing having a cylindrical body; a compression unit disposed inside the compressor housing for compressing a refrigerant; and a motor disposed inside the compressor housing, wherein the motor has a rotor and a stator core disposed on the outer circumference side of the rotor; the body has a first welded joint where the body is joined along the axial direction of the motor's rotation axis; the stator core has, in the circumferential direction of the stator core, a plurality of large-diameter portions in contact with the inner circumferential surface of the body, and a plurality of non-large-diameter portions where the distance from the center of the stator core to its outer circumferential surface is smaller than that of the large-diameter portions; and when viewed from the axial direction of the rotation axis, the non-large-diameter portions are arranged on a first straight line passing through the center of the stator core and the first welded joint along the radial direction of the stator core.

2. The compressor according to claim 1, wherein the stator core has a plurality of second welds where the inner circumferential surface of the body and the outer circumferential surface of the stator core are joined, and each of the plurality of second welds is located in any of the plurality of non-large diameter portions, excluding the first straight line.

3. The compressor according to claim 2, wherein the stator core is provided with reinforcing portions near each of the plurality of second welds to increase the mechanical strength of the non-large diameter portions.

4. The compressor according to claim 2, wherein the plurality of second welds are arranged at equal intervals in the circumferential direction of the stator core.

5. The compressor according to claim 1, wherein, when viewed from the axial direction of the rotating shaft, the large-diameter portion is arranged on a second straight line perpendicular to the first straight line, passing through the center of the stator core in the radial direction of the stator core.

6. The compressor according to claim 1, wherein each of the plurality of large-diameter portions of the stator core is provided with a reinforcing portion to increase the mechanical strength of the large-diameter portion.

7. The compressor according to any one of claims 1 to 6, wherein the plurality of non-large diameter portions include a plurality of small diameter portions having an arc-shaped outer surface and a plurality of groove portions formed along the axial direction of the rotating shaft through which lubricating oil in the compressor housing passes, and at least one of the small diameter portions is arranged on the first straight line.

Images