Compressors and air conditioners

Abstract

The present invention provides a compressor and the like equipped with an electric motor with an outer rotor structure that drives with high efficiency. [Solution] The compressor 100 comprises a sealed container 1, an electric motor 7, a crankshaft 3, and a compression mechanism 2. The electric motor 7 has an outer rotor structure in which a rotor 72 is arranged on the outer circumference of a stator 71. The rotor 72 comprises a rotor core 72a, a plurality of permanent magnets 72b embedded in the rotor core 72a, and a rotor cup 72f arranged on the outer circumference of the rotor core 72a and fixed to the crankshaft 3. The rotor core 72a is fixed to the rotor cup 72f at one end in the axial direction, and a radial gap is provided between the rotor core 72a and the rotor cup 72f over the entire circumference in a predetermined range in the axial direction.

Description

Technical Field

[0001] The present disclosure relates to a compressor and an air conditioner.

Background Art

[0002] Regarding a compressor provided with an outer rotor structure motor, for example, the techniques described in Patent Documents 1 to 3 are known. That is, Patent Document 1 describes press-fitting in a state where a convex portion provided on the outer peripheral surface of a rotor yoke and a concave portion provided on the inner peripheral surface of a rotor cup are fitted together.

[0003] Further, Patent Document 2 describes forming a notch between adjacent magnetic pole portions in the circumferential direction on the inner peripheral surface of the rotor cup, and also describes fixing the rotor yoke and the rotor cup by press-fitting. Further, Patent Document 3 describes a hermetic motor compressor provided with an outer rotor structure motor unit.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the technologies described in Patent Documents 1 and 2, the rotor yoke (i.e., the rotor core) and the rotor cup are fixed by press-fitting, which necessitates ensuring a sufficient contact area. As a result, magnetic flux from the rotor yoke is more likely to leak through the rotor cup, leading to a decrease in the efficiency of the electric motor. Furthermore, because the rotor yoke and rotor cup are fixed by press-fitting, hysteresis losses due to residual stress may occur, potentially leading to a decrease in the efficiency of the electric motor.

[0006] Furthermore, while Patent Document 3 describes a sealed electric compressor equipped with an outer rotor structure, as mentioned above, it does not specifically describe a configuration for suppressing magnetic flux leakage. Thus, the technologies described in Patent Documents 1 to 3 have room for improvement in terms of increasing the efficiency of electric motors.

[0007] Therefore, the object of this disclosure is to provide a compressor, etc., equipped with an electric motor having an outer rotor structure that is driven with high efficiency. [Means for solving the problem]

[0008] To solve the aforementioned problems, the compressor according to the present disclosure comprises a sealed container, an electric motor having a stator and a rotor and housed in the sealed container, a shaft that rotates integrally with the rotor, and a compression mechanism that compresses a refrigerant as the shaft rotates, wherein the electric motor has an outer rotor structure in which the rotor is arranged on the outer circumference side of the stator, the rotor comprises a rotor core, a plurality of permanent magnets embedded in the rotor core, and a rotor cup arranged on the outer circumference side of the rotor core and fixed to the shaft, the rotor core is fixed to the rotor cup at one end in the axial direction, and a radial gap is provided between the rotor core and the rotor cup over the entire circumference in a predetermined range in the axial direction. [Effects of the Invention]

[0009] According to this disclosure, it is possible to provide a compressor, etc., equipped with an electric motor with an outer rotor structure that drives with high efficiency. [Brief explanation of the drawing]

[0010] [Figure 1] This is a longitudinal cross-sectional view of the compressor according to the first embodiment. [Figure 2] This is a perspective view showing a portion of the rotor of the electric motor, which is part of the compressor according to the first embodiment, with a cutout. [Figure 3] This is an exploded perspective view of the rotor of the electric motor included in the compressor according to the first embodiment. [Figure 4A] This is a plan view including the rotor of the electric motor provided in the compressor according to the first embodiment. [Figure 4B] This is a magnified view of area K1 in Figure 4A. [Figure 5A] This is a perspective view of the rotor core of the electric motor included in the compressor according to the second embodiment. [Figure 5B] This is a partially enlarged view including the rotor core of the electric motor provided in the compressor according to the second embodiment. [Figure 6A] This is a perspective view of the rotor core of the electric motor included in the compressor according to the first modified example of the second embodiment. [Figure 6B] This is a partially enlarged view including the rotor core of the electric motor provided in the compressor according to the first modification of the second embodiment. [Figure 7] This is a perspective view of the rotor core of the electric motor included in a compressor according to a second modification of the second embodiment. [Figure 8] This is a perspective view of the rotor core of the electric motor included in a compressor according to a third modified example of the second embodiment. [Figure 9] This is a diagram showing the configuration of an air conditioner according to the third embodiment. [Figure 10] This is a perspective view showing a modified compressor with a portion of the motor rotor cut out. [Modes for carrying out the invention]

[0011] ≪First Embodiment≫ <Compressor Configuration> Figure 1 is a longitudinal cross-sectional view of the compressor 100 according to the first embodiment. The compressor 100 shown in Fig. 1 is a scroll compressor that compresses gaseous refrigerant. As shown in Fig. 1, the compressor 100 includes a sealed container 1, a compression mechanism section 2, a crankshaft 3 (shaft), an oil feed pump 4, a main bearing 5, a swivel bearing 6, an electric motor 7, and a thrust bearing 8.

[0012] The sealed container 1 is a container that houses the compression mechanism section 2, the crankshaft 3, the electric motor 7, etc., and is substantially sealed. The sealed container 1 is formed of a predetermined metal that is a magnetic material. Lubricating oil for lubricating the compression mechanism section 2 and each bearing is enclosed in the sealed container 1 and stored as an oil sump D1 at the bottom of the sealed container 1. The sealed container 1 includes a cylindrical cylinder chamber 1a, a lid chamber 1b that closes the upper side of the cylinder chamber 1a, and a bottom chamber 1c that closes the lower side of the cylinder chamber 1a.

[0013] The suction pipe P1 and the discharge pipe P2 are fixed to the lid chamber 1b of the sealed container 1 in a state where they are inserted. The suction pipe P1 is a pipe that guides refrigerant to the suction chamber (not shown) of the compression mechanism section 2. The discharge pipe P2 is a pipe that guides the refrigerant compressed by the compression mechanism section 2 to the outside of the compressor 100. In the example of Fig. 1, the discharge pipe P2 is inserted into the lid chamber 1b, but instead, the discharge pipe P2 may be inserted into a predetermined location of the cylinder chamber 1a. A plurality of legs E1 for supporting the sealed container 1 are provided at the lower part of the bottom chamber 1c.

[0014] The compression mechanism section 2 is a mechanism that compresses refrigerant as the crankshaft 3 (shaft) rotates. The compression mechanism section 2 includes a fixed scroll 21, a swivel scroll 22, a frame 23, and an oldham ring 24.

[0015] The fixed scroll 21 is a member that forms a compression chamber C1 together with the swivel scroll 22. The fixed scroll 21 is installed above the frame 23 and fixed to the frame 23 with bolts (not shown). As shown in Fig. 1, the fixed scroll 21 includes a base plate 21a, a support portion 21b, and a fixed wrap 21c, and these are integrally formed.

[0016] The base plate 21a is a thick, disc-shaped plate. A suction chamber (not shown) is provided at a predetermined location near the periphery of the base plate 21a. The suction chamber is a space through which the refrigerant is guided via the suction pipe P1. A discharge port V1 is also provided near the center of the base plate 21a. The discharge port V1 is an opening that guides the refrigerant compressed in the compression chamber C1 to the discharge space C2 above the compression mechanism 2.

[0017] The support portion 21b is a cylindrical part that supports the base plate 21a and is provided on the periphery of the base plate 21a so as to surround the fixed wrap 21c. The annular lower surface of the support portion 21b is called the end plate surface 21d. The end plate surface 21d is the sliding surface on which the support portion 21b of the fixed scroll 21 contacts the end plate 22a of the orbiting scroll 22. The height position of the end plate surface 21d is approximately equal to the height position of the tooth tip of the fixed wrap 21c. The fixed wrap 21c, together with the orbiting wrap 22b, forms the compression chamber C1. The fixed wrap 21c has a spiral shape when viewed from below and extends downward from the base plate 21a.

[0018] The orbiting scroll 22 is a component that orbits in conjunction with the rotation of the crankshaft 3 and forms a compression chamber C1 between itself and the fixed scroll 21. The orbiting scroll 22 is positioned below the fixed scroll 21 and faces the fixed scroll 21 in the vertical direction. As shown in Figure 1, the orbiting scroll 22 comprises an end plate 22a, an orbiting wrap 22b, and a boss portion 22c, which are integrally formed.

[0019] The end plate 22a is the part that slides between the end plate surface 21d of the fixed scroll 21 and has a disc shape. The orbital wrap 22b has a spiral shape in plan view and extends upward from the end plate 22a. A compression chamber C1 is formed between the fixed wrap 21c and the orbital wrap 22b. The boss portion 22c has a cylindrical shape and extends downward from the center of the back surface of the end plate 22a. The boss portion 22c is fitted into the eccentric portion 3c of the crankshaft 3.

[0020] The frame 23 is a component that supports the fixed scroll 21 and pivotally supports the crankshaft 3 via the main bearing 5. The frame 23 has a generally rotationally symmetrical shape and is fixed to the inner circumferential surface of the cylindrical chamber 1a by welding or the like. A predetermined flow path (not shown) for refrigerant flow is provided between the upper part of the frame 23 and the cylindrical chamber 1a. The lower part of the frame 23 extends in a long, slender cylindrical shape along the outer circumferential surface of the crankshaft 3. As will be described in detail later, the stator 71 is fixed to the lower part of the frame 23.

[0021] The frame 23 is provided with a through hole (not shown) through which the crankshaft 3 is inserted. The frame 23 is also provided with a lubricating oil outlet hole 23a. The lubricating oil that rises through the lubrication through hole 3d of the crankshaft 3 and lubricates each bearing flows out through the outlet hole 23a of the frame 23.

[0022] The Oldham ring 24 is a ring-shaped member that, in response to the eccentric rotation of the eccentric portion 3c described later, causes the orbiting scroll 22 to orbit while constraining it without allowing it to rotate on its own axis. The Oldham ring 24 is installed in a groove (not shown) on the lower surface of the orbiting scroll 22, as well as in a groove (not shown) on the frame 23.

[0023] The crankshaft 3 (shaft) is an axial member that rotates integrally with the rotor 72 of the electric motor 7. The crankshaft 3 is positioned substantially coaxially with the central axis of the fixed scroll 21 and extends in the vertical direction. As shown in Figure 1, the crankshaft 3 comprises a main shaft portion 3a, a flange portion 3b, and an eccentric portion 3c.

[0024] The main shaft portion 3a is coaxially fixed to the rotor cup 72f of the electric motor 7 and rotates integrally with the rotor 72, including the rotor cup 72f. The flange portion 3b is a part that restricts the downward movement of the crankshaft 3 and protrudes radially outward from the main shaft portion 3a. The flange portion 3b is provided between the main shaft portion 3a and the eccentric portion 3c in the vertical direction and is locked to the frame 23 via a thrust bearing 8. The thrust bearing 8 is a bearing that receives the axial (thrust direction) load of the crankshaft 3 and is installed between the flange portion 3b and the frame 23.

[0025] The eccentric portion 3c is a part that rotates eccentrically with respect to the main shaft portion 3a, and as described above, it is fitted into the boss portion 22c of the orbital scroll 22. As the eccentric portion 3c rotates eccentrically, the orbital scroll 22 rotates to a predetermined position.

[0026] The crankshaft 3 has an axially oriented oil supply through-hole 3d for guiding lubricating oil upward. A radial lateral hole 3e is also provided, communicating with the oil supply through-hole 3d. A portion of the lubricating oil rising through the oil supply through-hole 3d is then guided to the main bearing 5 through the lateral hole 3e.

[0027] The oil supply pump 4 is a pump for drawing lubricating oil from the oil reservoir D1 at the bottom of the sealed container 1, and is installed at the lower end of the crankshaft 3. For example, a centrifugal pump is used as such an oil supply pump 4. As the crankshaft 3 rotates, lubricating oil is drawn up sequentially from the oil reservoir D1 through the oil supply pump 4 and the oil supply through-hole 3d. This lubricating oil is used to lubricate each bearing and the compression mechanism 2.

[0028] The main bearing 5 rotatably supports the crankshaft 3 with respect to the frame 23. The main bearing 5 is installed on the circumferential surface of the insertion hole (the hole through which the crankshaft 3 is inserted) in the frame 23. The slewing bearing 6 rotatably supports the eccentric portion 3c of the crankshaft 3 with respect to the boss portion 22c of the slewing scroll 22, and is installed on the inner circumferential surface of the boss portion 22c.

[0029] The electric motor 7 is an outer rotor motor that rotates the crankshaft 3 and is housed in a sealed container 1. In the outer rotor structure, the rotor 72 is positioned on the outer circumference (i.e., radially outward) of the stator 71, making it easier to generate torque compared to the inner rotor structure, thus enabling higher output and a smaller size for the electric motor 7. The type of electric motor 7 may be, for example, a permanent magnet synchronous motor, but is not limited to this.

[0030] As shown in Figure 1, the electric motor 7 comprises a stator 71 and a rotor 72. The stator 71 is a stator for generating a predetermined rotating magnetic field and is fixed to the lower part of the frame 23 by press-fitting or the like. The stator 71 has a cylindrical stator core 71a and windings 71b wound around this stator core 71a.

[0031] The rotor 72 is a rotor that rotates at a predetermined rate in accordance with the rotating magnetic field of the stator 71. The rotor 72 is positioned on the outer circumference of the stator 71 and faces the stator 71 radially via a predetermined air gap. As shown in Figure 1, the rotor 72 comprises a rotor core 72a, a plurality of permanent magnets 72b, end plates 72c, a non-magnetic material 72d, a plurality of fastening members 72e (see Figure 2), and rotor cups 72f.

[0032] The rotor core 72a is a cylindrical iron core for forming a predetermined magnetic path (see also Figure 3). The rotor core 72a is constructed by stacking thin, annular electromagnetic steel sheets in the axial direction. Multiple permanent magnets 72b (see also Figure 3) are ferromagnetic materials that generate magnetic attraction and repulsion forces with the rotating magnetic field of the stator 71, and are embedded in the rotor core 72a.

[0033] The rotor cup 72f is a metal component that rotates the rotor 72 and the crankshaft 3 together, and is fixed to the crankshaft 3. The rotor cup 72f is located on the outer circumference (i.e., radially outward) of the rotor core 72a. The central axis of the rotor cup 72f is assumed to be approximately coaxial with the central axis of the rotor core 72a. The rotor cup 72f is formed of a predetermined magnetic material and has a bottomed cylindrical shape (see also Figure 3). The rotor cup 72f faces the cylindrical chamber 1a of the sealed container 1 with a radial gap in between.

[0034] A through-hole H1 (see Figure 2) is provided in the center of the disc-shaped bottom of the rotor cup 72f for the crankshaft 3 to pass through vertically. A key member for preventing rotation may be installed near the through-hole H1, although it is not shown in the figure. This key member restricts the rotation of the rotor cup 72f relative to the crankshaft 3. In addition, multiple flow holes H2a (see also Figure 2) are provided around the through-hole H1 (see Figure 2) in the disc-shaped bottom of the rotor cup 72f for the passage of refrigerant and lubricating oil.

[0035] A radial relief hole H2b is provided at the lower part of the peripheral wall of the rotor cup 72f. The relief hole H2b has the function of allowing lubricating oil to flow out from the inside to the outside of the rotor cup 72f by centrifugal force. The end plate 72c of the rotor 72, the non-magnetic material 72d, and the fastening member 72e (see Figure 2) will be described later.

[0036] Figure 2 is a perspective view of the motor's rotor 72 with a portion cut out. Figure 2 also shows a portion of the cylindrical chamber 1a of the sealed container 1. As shown in Figure 2, the rotor cup 72f comprises a thick-walled portion 721f, a bottom portion 722f, and a thin-walled portion 723f. The thick-walled portion 721f is a cylindrical portion whose radial thickness is greater than that of the thin-walled portion 723f. The bottom portion 722f extends radially inward from the lower end of the thick-walled portion 721f. As described above, the bottom portion 722f is provided with a through hole H1 for inserting the crankshaft 3 (see Figure 1), as well as a number of passage holes H2a for passing refrigerant and lubricating oil.

[0037] The thin-walled portion 723f is a cylindrical part whose radial thickness is thinner than that of the thick-walled portion 721f, and it extends upward from the upper surface of the thick-walled portion 721f. The outer circumferential surfaces of both the thick-walled portion 721f and the thin-walled portion 723f are smooth cylindrical surfaces. On the other hand, the upper surface of the portion of the thick-walled portion 721f that is located radially inward from the inner circumferential surface of the thin-walled portion 723f is an annular stepped surface S1 in plan view. A total of three insertion holes (not shown) are provided in this stepped surface S1 at equal intervals in the circumferential direction. The lower part of the fastening member 72e is inserted into the insertion holes of the stepped surface S1.

[0038] As shown in Figure 2, a non-magnetic material 72d is placed on the stepped surface S1. The non-magnetic material 72d is a thin, annular member designed to suppress magnetic flux leakage. As shown in Figure 2, the non-magnetic material 72d is sandwiched axially between the rotor core 72a and the rotor cup 72f on the underside (one side in the axial direction) of the rotor core 72a. As the constituent material of such a non-magnetic material 72d, for example, aluminum or aluminum alloys, as well as copper alloys, titanium alloys, and non-magnetic stainless steel can be used. The rotor core 72a and end plate 72c are then sequentially installed on top of the non-magnetic material 72d.

[0039] The end plate 72c is a thin, annular member that prevents the permanent magnet 72b from coming out of the magnet insertion hole H3 (see Figure 3). The inner and outer diameters of the end plate 72c correspond to the inner and outer diameters of the rotor core 72a, and it is installed on the upper side of the rotor core 72a.

[0040] The fastening member 72e is a magnetic material used to fasten the rotor core 72a and the rotor cup 72f. The fastening member 72e also has the function of integrating multiple electromagnetic steel plates, which are components of the rotor core 72a, in the axial direction. For example, a rivet can be used as such a fastening member 72e. The rotor core 72a is fixed to the rotor cup 72f at its lower end (one end in the axial direction) by the fastening member 72e.

[0041] Furthermore, the rotor cup 72f is fixed to the crankshaft 3 (see Figure 1) by press-fitting or shrink-fitting. The rotor cup 72f, together with the rotor core 72a, rotates as a single unit with the crankshaft 3. As will be described in more detail later, when the rotor core 72a is fixed to the rotor cup 72f at its lower end, a radial gap G1 (see Figure 4B) is provided around the entire circumference between the rotor core 72a and the rotor cup 72f.

[0042] Figure 3 is an exploded perspective view of the motor rotor 72. As shown in Figure 3, the rotor core 72a is provided with multiple magnet insertion holes H3 for inserting permanent magnets 72b. Multiple permanent magnets 72b are housed one by one in these magnet insertion holes H3. Note that the permanent magnets 72b housed in the magnet insertion holes H3 may be divided into multiple parts in the vertical or horizontal direction.

[0043] Furthermore, three thin, annular non-magnetic materials 72d are stacked and placed on the stepped surface S1 of the rotor core 72a. The number of non-magnetic materials 72d may be one, two, or four or more. The inner and outer diameters of the non-magnetic materials 72d correspond to the inner and outer diameters of the rotor core 72a. Therefore, the non-magnetic materials 72d are interposed between the rotor core 72a and the rotor cup 72f over the entire circumference in the circumferential direction. Above the non-magnetic materials 72d, the cylindrical rotor core 72a and the thin, annular end plates 72c are sequentially installed.

[0044] As shown in Figure 3, the end plate 72c has three through holes H4 provided at equal intervals in the circumferential direction for inserting the fastening member 72e. Similarly, the rotor core 72a also has three fastening holes H5, and each non-magnetic material 72d has three through holes H6. The fastening member 72e passes through the through holes H4 in the end plate 72c, the fastening holes H5 in the rotor core 72a, and the through holes H6 in the non-magnetic material 72d in sequence, and is inserted into the insertion hole of the stepped surface S1 of the rotor cup 72f (see also Figure 2). The predetermined range R1 shown in Figure 3 will be described later.

[0045] Figure 4A is a plan view including the rotor 72 of the electric motor. Figure 4A also shows the cylindrical chamber 1a of the sealed container 1. Furthermore, Figure 4A illustrates the state with the end plate 72c (see Figure 3) and fastening member 72e (see Figure 3) removed. As shown in Figure 4A, the rotor 72 includes a rotor core 72a and rotor cups 72f, as well as six pairs of permanent magnets 72b. Each pair of permanent magnets 72b, 72b is arranged to open in a V-shape toward the central axis Z1 of the rotor 72 in a plan view. A single magnetic pole portion M1 is formed by the pair of V-shaped permanent magnets 72b, 72b.

[0046] These magnetic pole sections M1 are arranged such that adjacent magnetic poles in the circumferential direction are opposite to each other. In the example shown in Figure 4A, the electric motor 7 is configured as a 6-pole motor having 6 magnetic pole sections M1, but the number of poles of the electric motor 7 is not limited to 6. Alternatively, a pair of permanent magnets 72b, 72b may be integrated so that one magnetic pole section is formed by one permanent magnet.

[0047] As described above, the rotor core 72a has three fastening holes H5 provided at equal intervals in the circumferential direction. More specifically, the fastening holes H5 are provided between the magnetic pole portions M1, which are composed of permanent magnets 72b, 72b. That is, the circumferential position of the fastening holes H5 is between the magnetic pole portions M1. One fastening member 72e (see Figure 3) is installed in each of these fastening holes H5. As described above, the fastening member 72e is a magnetic material for fastening the rotor core 72a and the rotor cup 72f.

[0048] In this manner, fastening holes H5 are provided between the magnetic pole portions M1, and a magnetic fastening member 72e (see Figure 3) is inserted through the fastening holes H5. This suppresses distortion of the rotor 72's magnetic field due to the influence of the fastening member 72e. As the magnetic material that makes up the fastening member 72e, for example, iron or an iron alloy can be used, but it is not limited to these.

[0049] <Regarding magnetic flux leakage> Generally, in electric motors with an outer rotor structure, the longer the outer diameter of the rotor, the greater the output torque of the motor. However, in conventional electric motors with an outer rotor structure, increasing the outer diameter of the rotor shortens the distance between the outer surface of the rotor (i.e., the outer surface of the rotor cup) and the inner surface of the sealed container, which tends to increase magnetic flux leakage from the rotor to the sealed container. When such magnetic flux leakage occurs, eddy current losses in the motor increase, leading to a decrease in efficiency. Note that the shorter the distance between the rotor and the sealed container, the greater the degree of magnetic flux leakage tends to be.

[0050] Thus, with conventional technology, when attempting to increase the outer diameter of the rotor to obtain a large output torque, there was a problem in that the efficiency of the electric motor decreased due to magnetic flux leakage. Therefore, in the first embodiment, a radial gap G1 (see Figure 4B) is provided around the entire circumference between the rotor core 72a and the rotor cup 72f. As a result, even when the outer surface of the rotor 72 is brought close to the inner surface of the sealed container 1, the gap G1 functions as a magnetic insulating layer, thereby suppressing magnetic flux leakage from the rotor 72. In other words, since it is possible to suppress the leakage of magnetic flux from the rotor core 72a to the sealed container 1 via the rotor cup 72f, the efficiency of the electric motor 7 (see Figure 1) can be increased.

[0051] <Gap between the rotor core and rotor cup> Figure 4B is a magnified view of area K1 in Figure 4A. As shown in Figure 4B, a radial gap G1 is provided between the rotor core 72a and the rotor cup 72f over the entire circumference within a predetermined axial range R1 (see Figure 3). The predetermined range R1 (see Figure 3) is set to the range from the lower end (one axial end) to the upper end (the other axial end) of the rotor core 72a. In short, a radial gap G1 is provided over the entire area between the rotor core 72a and the thin-walled portion 723f (see Figure 2) of the rotor cup 72f. Also, as mentioned above, the rotor core 72a is fixed to the rotor cup 72f at its lower end (one axial end) (see Figure 2).

[0052] According to such a configuration, even when the outer diameter of the rotor 72 (the outer diameters of the rotor core 72a and the rotor cup 72f) is maximally lengthened, magnetic flux leakage to the sealed container 1 through the rotor cup 72f can be suppressed. Therefore, the efficiency of the electric motor 7 (see FIG. 1) can be improved. Further, the rotor core 72a and the rotor cup 72f are axially fixed by a fastening member 72e (see FIG. 2), while not particularly contacting each other in the radial direction. That is, since there is no particular need to press-fit the rotor core 72a into the rotor cup 72f, almost no residual stress is generated in the rotor 72. As a result, the generation of hysteresis loss associated with the residual stress can be suppressed, and the efficiency of the electric motor 7 (see FIG. 1) can be improved.

[0053] In addition, the outer peripheral surface of the rotor core 72a is smooth and cylindrical (see also FIG. 3). That is, the rotor core 72a is not particularly provided with protrusions as described in the second embodiment (see FIG. 5A). Further, the inner peripheral surface of the thin portion 723f (see FIG. 2) of the rotor cup 72f is also smooth and cylindrical.

[0054] Also, the relationship between the radial distance L1 between the rotor core 72a and the rotor cup 72f and the radial distance L2 between the rotor cup 43b and the sealed container 1 is preferably set such that (L1 + L2) ≤ 4 [mm]. As described above, since the gap G1 as a magnetic insulation layer is provided, magnetic flux leakage to the sealed container 1 can be suppressed even if the rotor core 72a and the rotor cup 72f are brought quite close to the sealed container 1. Note that the magnitude relationship between the distances L1 and L2 described above is appropriately set at the design stage. For example, the distance L1 may be longer than the distance L2 (L1 > L2), vice versa (L1 < L2), or the distances L1 and L2 may be equal to each other (L1 = L2).

[0055] Furthermore, a non-magnetic material 72d (see Figure 2) is sandwiched between the rotor core 72a and the rotor cup 72f in the axial direction. This also suppresses axial magnetic flux leakage from the permanent magnet 72b to the rotor cup 72f. For example, a non-magnetic material 72d (see Figure 2) made of relatively high-strength aluminum may be stacked in the axial direction. In this case, the thickness of the magnetic insulating layer formed by the non-magnetic material 72d may be 3 [mm] or more, but is not limited to this.

[0056] <Effects> In the first embodiment, a radial gap G1 (see Figure 4B) is provided around the entire circumference of the rotor core 72a and the rotor cup 72f, from the lower end to the upper end of the rotor core 72a. With this configuration, magnetic flux leakage to the sealed container 1 via the rotor cup 72f can be sufficiently suppressed. Therefore, the outer diameter of the rotor core 72a and rotor cup 72f can be maximized at the design stage, thereby improving the performance and efficiency of the electric motor 7. In addition, since there is no particular need to fix the rotor core 72a and rotor cup 72f by press-fitting, deformation and distortion of the rotor core 72a due to residual stress can be suppressed, and consequently, hysteresis loss can be reduced. Thus, according to the first embodiment, a compressor 100 equipped with an electric motor 7 with an outer rotor structure that drives with high efficiency can be provided.

[0057] ≪Second Embodiment≫ The second embodiment differs from the first embodiment in that a plurality of protrusions 722a (see Figure 5A) are provided on the outer circumferential surface of the rotor core 72Aa (see Figure 5A). Other configurations (such as the rotor cup 72f) are the same as in the first embodiment. Therefore, the differences from the first embodiment will be described, and the overlapping parts will be omitted from the explanation.

[0058] Figure 5A is a perspective view of the rotor core 72Aa of the electric motor included in the compressor according to the second embodiment. As shown in Figure 5A, the rotor core 72Aa has a cylindrical body portion 721a and a plurality of protrusions 722a projecting radially outward from the outer circumferential surface of the body portion 721a. In the example in Figure 5A, three protrusions 722a are provided at equal intervals in the circumferential direction. These protrusions 722a are provided to align the axes between the rotor core 72Aa and the rotor cup 72f (see Figure 3) (i.e., for coaxial alignment). Specifically, a plurality of protrusions 722a are provided to suppress misalignment of the central axis of the rotor cup 72f (see Figure 3) with respect to the central axis of the rotor core 72Aa.

[0059] Furthermore, press-fitting is not particularly necessary for the fitting between the rotor core 72Aa and the rotor cup 72f (see Figure 3); for example, clearance fitting or slight interference fitting can be used. Therefore, deformation or distortion of the rotor core 72Aa during fitting with the rotor cup 72f is minimal, thus suppressing hysteresis loss.

[0060] In the example shown in Figure 5A, the upper end of each projection 722a is substantially flush with the upper surface of the cylindrical main body 721a. The projection 722a extends downward from its upper end by a predetermined length. This predetermined length is shorter than the axial length of the main body 721a. For example, the axial length of the projection 722a may be shorter than half the total axial length of the rotor core 72Aa. This reduces the contact area between the projection 722a and the rotor cup 72f sufficiently, thereby suppressing magnetic flux leakage through the projection 722a.

[0061] The curvature of the circumferential surface of the projection 722a is approximately the same as the curvature of the inner circumferential surface of the rotor cup 72f (see Figure 5B). Furthermore, the length of the projection 722a protruding radially from the main body 721a may be approximately equal to the radial length of the gap G1 (see Figure 5B) between the rotor core 72Aa and the rotor cup 72f (see Figure 5B), or it may be slightly longer than the radial length of this gap G1. The number, arrangement, and dimensions of the projections 722a can be appropriately changed considering the ease of assembly between the rotor core 72Aa and the rotor cup 72f. The predetermined range R2 shown in Figure 5B will be described later.

[0062] Figure 5B is a partially enlarged view including the rotor core 72Aa. Figure 5B is a partially enlarged view of a portion of the rotor core 72Aa in a plan view. In addition to the rotor core 72Aa, Figure 5B also shows the rotor cup 72f and the cylindrical chamber 1a of the sealed container 1. As shown in Figure 5B, a radial gap G1 is provided between the rotor core 72Aa and the rotor cup 72f. This gap G1 is provided around the entire circumference of the rotor core 72Aa in a predetermined axial range R2 (see Figure 5A).

[0063] The aforementioned predetermined range R2 (see Figure 5A) is a part of the range from the lower end (one axial end) to the upper end (the other axial end) of the rotor core 72Aa. More specifically, the predetermined range R2 (see Figure 5A) is the range of the rotor core 72Aa in the axial direction, excluding the range in which the projections 722a exist. Each projection 722a is located outside the predetermined range R2 (see Figure 5A) in the axial direction of the rotor core 72Aa and is in contact with the inner circumferential surface of the rotor cup 72f. In the example of Figure 5B, the circumferential surface of the projection 722a is in contact with the inner circumferential surface of the rotor cup 72f.

[0064] Furthermore, it is preferable that the circumferential position of the projection 722a be at the center of the circumferential direction of the magnetic pole section M1, which is composed of permanent magnets 72b, 72b. At the center of the circumferential direction of the magnetic pole section M1, the magnetic field is weaker and the magnitude of the magnetic flux is smaller compared to other positions. Therefore, by providing the projection 722a at the center of the circumferential direction of the magnetic pole section M1, it is possible to suppress distortion of the magnetic field of the rotor 72 due to the influence of the projection 722a.

[0065] Furthermore, it is preferable that the central angle θ1 of a predetermined arc indicating the circumferential range of the projection 722a (the central angle with respect to the central axis of the rotor core 72Aa) is smaller than the pole arc angle θ2 of the magnetic pole portion M1 (θ1 < θ2). Here, the pole arc angle θ2 of the magnetic pole portion M1 refers to the central angle of the arc corresponding to the circumferential range of one magnetic pole portion M1 (the central angle with respect to the central axis of the rotor core 72Aa). With this configuration, the contact area between the projection 722a and the rotor cup 72f is reduced, thereby suppressing magnetic flux leakage through the projection 722a.

[0066] In the example shown in Figure 5B, the central angle θ1 of the arc representing the circumferential range of the projection 722a is 20% or less of the pole arc angle θ2 of the magnetic pole portion M1. This makes the contact area between the projection 722a and the rotor cup 72f sufficiently small, thereby effectively suppressing magnetic flux leakage. As mentioned above, the projection 722a is for aligning the axis between the rotor core 72Aa and the rotor cup 72f, so there is no particular need to ensure a wide contact area between the projection 722a and the rotor cup 72f by considering press-fitting or the like.

[0067] <Effects> According to the second embodiment, a radial gap G1 (see Figure 5B) between the rotor core 72Aa and the rotor cup 72f is provided around the entire circumference within a predetermined axial range R2 (see Figure 5A) of the rotor core 72Aa. This suppresses magnetic flux leakage to the sealed container 1 via the rotor cup 72f, thereby improving efficiency.

[0068] Furthermore, multiple protrusions 722a of the rotor core 72Aa are in contact with the inner circumferential surface of the rotor cup 72f (see Figure 5B). This allows the axis to be aligned between the rotor core 72Aa and the rotor cup 72f. As a result, the radial length of the gap G1 (see Figure 5B) between the rotor core 72Aa and the rotor cup 72f is more easily maintained to be substantially uniform in the circumferential direction. In addition, by aligning the axis between the rotor core 72Aa and the rotor cup 72f, vibrations of the compressor 100 can be suppressed, as well as runout and uneven contact of the crankshaft 3.

[0069] <<First Modification of the Second Embodiment>> Figure 6A is a perspective view of the rotor core 72Ba of the electric motor included in the compressor according to the first modified example of the second embodiment. As shown in Figure 6A, projections 722Ba (see also Figure 6B) with a semicircular cross-section may be provided in the axial direction. In the example in Figure 6A, three projections 722Ba are provided at equal intervals in the circumferential direction. The predetermined range R2 in Figure 6A indicates the range (axial range) in which a radial gap G1 (see Figure 6B) is provided between the rotor core 72Ba and the rotor cup 72f (see Figure 6B). This is the same as in the second embodiment (see Figure 5A), so the explanation is omitted.

[0070] Figure 6B is a partially enlarged view including the rotor core 72Ba. Figure 6B is a magnified view of a portion of the rotor core 72Ba in a plan view. In addition to the rotor core 72Ba, Figure 6B also shows the rotor cup 72f and the cylindrical chamber 1a of the sealed container 1. As shown in Figure 6B, a projection 722Ba with a semicircular cross-section is provided. The radial tip of the projection 722Ba is in contact with the inner circumferential surface of the rotor cup 72f. As mentioned above, since the projection 722Ba extends axially for a predetermined length (see Figure 6A), the tip of the projection 722Ba is in line contact with the rotor cup 72f (the contact area is linear). Since the projection 722Ba is for aligning the axes of the rotor core 72Ba and the rotor cup 72f, this type of line contact does not pose any particular problem.

[0071] Furthermore, the cross-sectional shape of the projection 722Ba is not limited to a semicircular shape, but may be other shapes such as a triangular shape. Also, for example, the projection of the rotor core 72Ba may be made hemispherical, so that this projection and the rotor cup 72f make point contact (the contact area is point-like).

[0072] ≪Second Modification of the Second Embodiment≫ Figure 7 is a perspective view of the rotor core 72Ca of the electric motor included in a compressor according to a second modified example of the second embodiment. In the example shown in Figure 7, instead of the projection 722a described in the second embodiment (see Figure 5A), a pair of divided projections 722Ca, 722Ca are provided. The pair of projections 722Ca, 722Ca are arranged at a predetermined distance apart in the axial direction of the rotor core 72Ca. The circumferential position and range of the projections 722Ca, 722Ca are the same as in the second embodiment (see Figure 5A), so a description is omitted.

[0073] Although not shown in the diagram, a radial gap is provided between the rotor core 72Ca and the rotor cup 72f (see Figure 3). This gap extends around the entire circumference of the rotor core 72Aa in a predetermined axial range R3. The aforementioned predetermined range R3 (the union of ranges R31, R32, and R33 shown in Figure 7) is the range from the lower end to the upper end of the rotor core 72Ca, excluding the range where the pair of upper and lower protrusions 722Ca, 722Ca exist. Even with this configuration, the same effects as in the second embodiment are achieved.

[0074] ≪Third Modification of the Second Embodiment≫ Figure 8 is a perspective view of the rotor core 72Da of the electric motor included in a compressor according to a third modified example of the second embodiment. In the example shown in Figure 8, adjacent protrusions 722Da are arranged in a staggered pattern in the circumferential direction. The circumferential position of each protrusion 722Da is at the circumferential center of the magnetic pole portion M1. A total of six protrusions 722Da are provided to correspond to a total of six magnetic pole portions M1. Note that in Figure 8, the three protrusions 722Da on the near side of the page are shown, and the remaining three protrusions 722Da on the far side of the page are not visible.

[0075] Although not shown in the diagram, a radial gap is provided between the rotor core 72Da and the rotor cup 72f (see Figure 3). This gap extends around the entire circumference of the rotor core 72Da in a predetermined axial range R4. The aforementioned predetermined range R4 (the union of ranges R41, R42, and R43 shown in Figure 8) is the range from the lower end to the upper end of the rotor core 72Da, excluding the range in which the protrusion 722Da exists. This configuration also achieves the same effects as the second embodiment (see Figure 5A).

[0076] ≪Third Embodiment≫ In the third embodiment, an air conditioner W1 (see Figure 9) equipped with the compressor 100 (see Figure 1) described in the first embodiment will be described.

[0077] Figure 9 is a diagram showing the configuration of the air conditioner W1 according to the third embodiment. The solid arrows in Figure 9 indicate the flow of refrigerant during the heating cycle. On the other hand, the dashed arrows in Figure 9 indicate the flow of refrigerant in the cooling cycle. The air conditioner W1 is a device that performs air conditioning, such as cooling and heating. As shown in Figure 9, the air conditioner W1 is equipped with a compressor 100, an outdoor heat exchanger 81, an outdoor fan 82, an expansion valve 83, a four-way valve 84, an indoor heat exchanger 85, and an indoor fan 86.

[0078] In the example shown in Figure 9, the compressor 100, outdoor heat exchanger 81, outdoor fan 82, expansion valve 83, and four-way valve 84 are installed in the outdoor unit U1. The indoor heat exchanger 85 and indoor fan 86 are installed in the indoor unit U2.

[0079] The compressor 100 is a device that compresses refrigerant gas and has the same configuration as the first embodiment (see Figure 1). The outdoor heat exchanger 81 is a heat exchanger in which heat exchange takes place between the refrigerant flowing through its heat transfer tubes (not shown) and the outside air supplied by the outdoor fan 82. The outdoor fan 82 is a fan that supplies outside air to the outdoor heat exchanger 81. The outdoor fan 82 is equipped with an outdoor fan motor 82a, which is its driving source, and is installed near the outdoor heat exchanger 81.

[0080] The indoor heat exchanger 85 is a heat exchanger in which heat exchange takes place between a refrigerant flowing through its heat transfer tubes (not shown) and indoor air (air from the air-conditioned room) supplied by the indoor fan 86. The indoor fan 86 is a fan that supplies indoor air to the indoor heat exchanger 85. The indoor fan 86 is equipped with an indoor fan motor 86a, which is its driving source, and is installed near the indoor heat exchanger 85.

[0081] The expansion valve 83 is a valve that reduces the pressure of the refrigerant condensed in the "condenser" (one of the outdoor heat exchanger 81 and the indoor heat exchanger 85). The refrigerant reduced in pressure by the expansion valve 83 is then led to the "evaporator" (the other of the outdoor heat exchanger 81 and the indoor heat exchanger 85).

[0082] The four-way valve 84 is a valve that switches the flow path of the refrigerant according to the operating mode of the air conditioner W1. For example, during cooling operation (see dashed arrow in Figure 9), the refrigerant circulates sequentially through the compressor 100, outdoor heat exchanger 81 (condenser), expansion valve 83, and indoor heat exchanger 85 (evaporator). On the other hand, during heating operation (see solid arrow in Figure 9), the refrigerant circulates sequentially through the compressor 100, indoor heat exchanger 85 (condenser), expansion valve 83, and outdoor heat exchanger 81 (evaporator).

[0083] <Effects> According to the third embodiment, since the air conditioner W1 is equipped with a highly efficient compressor 100, the overall performance and efficiency of the air conditioner W1 can be improved.

[0084] ≪Variations≫ Although the compressor 100 and air conditioner W1 related to this disclosure have been described in each embodiment above, the invention is not limited to these descriptions and various modifications can be made. For example, in the first embodiment, a case was described in which a thin, annular nonmagnetic material 72d (see Figure 2) is sandwiched between the rotor core 72a (see Figure 2) and the rotor cup 72f (see Figure 2). However, the system is not limited to this, and the following configurations may also be used.

[0085] Figure 10 is a perspective view showing a modified compressor with a portion of the motor rotor 72E cut out. As shown in Figure 10, an annular washer 72g made of a non-magnetic material may be arranged around the fastening member 72e. In the example in Figure 10, two washers 72g are stacked in the axial direction (the axial direction of the rotor 72E) and placed on the stepped surface S1 between the thick portion 721f and the thin portion 723f.

[0086] The fastening member 72e passes through the hole in the washer 72g and is inserted into the insertion hole (not shown) of the stepped surface S1 of the rotor cup 72f. As a result, in the region that does not overlap with the washer 72g in a plan view, a predetermined space G2 (magnetic insulating layer) is provided in the axial direction between the rotor core 72a and the rotor cup 72f, thereby suppressing magnetic flux leakage in the axial direction. In this way, a predetermined space G2 may be provided between the lower surface (end face on one end) of the rotor core 72a and the stepped surface S1 of the rotor cup 72f that is facing the lower surface of the rotor core 72a.

[0087] Furthermore, although each embodiment describes the case in which rivets are used as fastening members 72e (see Figure 2) of the rotor 72, the invention is not limited to this. For example, bolts or knock pins may be used as fastening members 72e. Also, although each embodiment describes the case in which multiple electromagnetic steel sheets constituting the rotor core 72a are integrated with fastening members 72e, the invention is not limited to this. For example, the multiple electromagnetic steel sheets may be integrated by laser welding or core crimping. In this case, fastening holes may be provided in the lower part of the rotor core 72a, and fastening and axis alignment may be performed by inserting knock pins or the like into these holes.

[0088] Furthermore, while each embodiment describes a case where the crankshaft 3 is supported in a cantilevered manner using the frame 23 (see Figure 1), the invention is not limited to this. For example, a subframe (not shown) may be provided separately to support the lower part of the crankshaft 3 (the lower side of the electric motor 7), so that the crankshaft 3 is supported in a double-sided manner by the frame 23 and the subframe.

[0089] Furthermore, each embodiment can be combined as appropriate. For example, the second and third embodiments may be combined so that the compressor of the air conditioner W1 (see Figure 9) has the following configuration. That is, the compressor may be equipped with an electric motor in which the rotor core 72Aa (see Figure 5A) has a plurality of protrusions 722a (see Figure 5A). Many other combinations are also possible.

[0090] Furthermore, although each embodiment describes the case in which the compressor 100 (see Figure 1) is used in a vertical orientation, it is not limited to this. For example, each embodiment can also be applied when the compressor 100 is used in a horizontal or diagonal orientation. Furthermore, although each embodiment describes the case where the compressor 100 is a scroll-type compressor, it is not limited to this. For example, each embodiment can be applied to other types of compressors such as rotary compressors and reciprocating compressors.

[0091] Furthermore, although the third embodiment described a case in which the air conditioner W1 (see Figure 9) is equipped with a four-way valve 84, it is not limited to this. That is, the four-way valve 84 may be omitted as appropriate, and the air conditioner may be used for cooling only or heating only.

[0092] Furthermore, the air conditioner W1 (see Figure 9) described in the third embodiment can be applied to various types of air conditioners, such as multi-split air conditioners for buildings, packaged air conditioners, and room air conditioners. Also, although the third embodiment describes an air conditioner W1 (see Figure 9) equipped with a compressor 100, it is not limited to this. For example, the third embodiment can also be applied to other refrigeration cycle devices such as chillers, water heaters, air conditioning and water heating systems, chillers, and refrigerators.

[0093] Furthermore, each embodiment is described in detail for the purpose of clearly illustrating this disclosure and is not necessarily limited to having all the configurations described. In addition, it is possible to add, delete, or replace some of the configurations in each embodiment as appropriate. Furthermore, the mechanisms and configurations described above are those deemed necessary for explanatory purposes and do not necessarily represent all of the mechanisms and configurations shown in the actual product. [Explanation of Symbols]

[0094] 1. Airtight container 2 Compression mechanism 3. Crankshaft (shaft) 4. Fuel pump 5 Main bearings 6. Swivel bearing 7 Electric motor 21 Fixed Scroll 22 Swivel Scroll 23 frames 24 Oldham Ring 71 stata 71a Stator Core 71b Winding 72, 72E Rotor 72a, 72Aa, 72Ba, 72Ca, 72Da, Rotor core 72b Permanent magnet 72c end plate 72d Non-magnetic material 72e Fastening member 72f Rotor Cup 81 Outdoor heat exchanger 82 Outdoor fan 83 Expansion valve 84 Four-way valve 85 Indoor heat exchanger 86 Indoor Fan 100 Compressors 721a Main body 722a,722Ba,722Ca,722Da protrusion G1 Gap G2 space H5 Fastening hole M1 magnetic pole part R1, R2, R3, R4 predetermined range S1 step surface Z1 center axis

Claims

1. A sealed container, An electric motor having a stator and a rotor, and housed in the sealed container, A shaft that rotates integrally with the rotor, It comprises a compression mechanism that compresses the refrigerant as the shaft rotates, The electric motor has an outer rotor structure in which the rotor is arranged on the outer circumference side of the stator. The rotor comprises a rotor core, a plurality of permanent magnets embedded in the rotor core, and a rotor cup positioned on the outer circumference of the rotor core and fixed to the shaft. The rotor core is fixed to the rotor cup at one end in the axial direction. A compressor in which a radial gap is provided between the rotor core and the rotor cup over the entire circumference within a predetermined range in the axial direction.

2. The predetermined range is the range from one end to the other end in the axial direction of the rotor core. The compressor according to claim 1, characterized by the following:

3. The predetermined range is a part of the range from one end to the other end in the axial direction of the rotor core. The rotor core has a cylindrical body and a plurality of protrusions projecting radially outward from the outer circumferential surface of the body. Each of the aforementioned protrusions is provided outside the predetermined range in the axial direction of the rotor core and is in contact with the inner circumferential surface of the rotor cup. The compressor according to claim 1, characterized by the following:

4. The circumferential position of the projection is the center in the circumferential direction of the magnetic pole portion composed of the permanent magnet. The central angle of a predetermined circular arc indicating the circumferential range of the projection is smaller than the polar arc angle of the magnetic pole portion. The compressor according to claim 3, characterized by the following:

5. The rotor has a fastening member which is a magnetic material that fastens the rotor core and the rotor cup together. The fastening member is installed in the fastening hole of the rotor core, The circumferential position of the fastening hole is between the magnetic pole portions composed of the permanent magnet. The compressor according to claim 1, characterized by the following:

6. At one end in the axial direction, a non-magnetic material is sandwiched in the axial direction between the rotor core and the rotor cup. The compressor according to claim 1, characterized by the following:

7. A predetermined space is provided between the end face of one end of the rotor core and the stepped surface of the rotor cup facing the end face. The compressor according to claim 1, characterized by the following:

8. An air conditioner comprising a compressor according to any one of claims 1 to 7, an outdoor heat exchanger, an expansion valve, and an indoor heat exchanger.

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