JP6329586B2 - Electric motor and air conditioner using the same - Google Patents

Description

  The present invention relates to an electric motor and an air conditioner using the same.

  Currently, R410A, which is widely used as a refrigerant for air conditioners, has a global warming potential of 2088 and is required to use a refrigerant with a smaller environmental load. As a candidate for this, use of R32 having a global warming potential of 675 (that is, about one-third of R410) as a refrigerant is under study.

  By the way, in the electric motor used for an air conditioner, between a coil | winding and a stator iron core is insulated with an insulating material, and the electric current leakage from a coil | winding to a stator iron core is suppressed. However, R32 has a higher dielectric constant than R410A. Therefore, when R32 is employed as the refrigerant, the leakage current cannot be sufficiently reduced even if the windings of the motor used in the air conditioner and the stator core are insulated with an insulating material.

  Patent Document 1 describes that the stator core or the insulating paper has a plurality of irregularities, reduces the contact area between the insulating paper and the stator core, reduces the floating capacitance, and can reduce the leakage current. Has been.

JP-A-8-107642

  However, in the case of an electric motor used for a compressor of an air conditioner, the inside is filled with a refrigerant. Therefore, even if a plurality of irregularities are provided on the stator core or the insulating paper, the refrigerant accumulates in the gap between the insulating paper and the stator core. Therefore, even if the electric motor of Patent Document 1 is used as a compressor for an air conditioner, the floating capacitance between the winding and the stator core cannot be reduced, and the leakage current cannot be sufficiently suppressed. .

The objective of this invention is providing the electric motor which suppressed the leakage current resulting from the floating electrostatic capacitance between a coil | winding and a stator iron core, and an air conditioner using the same .

In order to achieve the above object, an electric motor according to the present invention includes a compression mechanism for compressing and discharging a refrigerant, and an electric motor housed in a sealed container together with lubricating oil, and a stator iron core and a bearing for the stator iron core. A fixed coil having insulators disposed at both ends in a direction, a coil wound around the stator iron core and the insulator by a concentrated winding method, and an insulating material disposed between the stator iron core and the coil. The stator iron core includes a stator iron core annular portion and a plurality of teeth portions protruding radially inward from an inner peripheral surface of the stator iron core annular portion, and the insulator is And an insulator annular portion, and a plurality of trunk portions projecting radially inward from an inner circumferential surface of the insulator annular portion, wherein a circumferential width of the trunk portion is larger than a circumferential width of the teeth portion. , said coil The gap is provided between the coil and the stator iron core by being wound around the body part and the tooth part, and the insulating material is provided between the coil and the stator iron core. The coil and the insulating material are in contact with each other, and the distance between the coil and the stator core is longer than the thickness of the insulating material, and the stator iron There is a gap between the core and the insulating material , refrigerant and refrigeration oil accumulate in the gap between the stator iron core and the insulating material, and the dielectric constant of the insulating material is the coil and the fixed It is characterized by being lower than the dielectric constant in the gap between the iron core.

ADVANTAGE OF THE INVENTION According to this invention, the electric motor which suppressed the leakage current resulting from the floating electrostatic capacitance between a coil | winding and a stator iron core, and an air conditioner using the same can be provided.

Schematic of air conditioner combined with air conditioning Compressor longitudinal section Perspective view of stator core Bottom view of insulator Insulator perspective view Sectional view in the circumferential direction of the teeth part of the stator core and the body part of the insulator Explanatory drawing of folded part at both ends of insulation Sectional view in the circumferential direction of the teeth part of the stator core and the body part of the insulator

  Embodiments of the present invention will be described in detail with reference to the drawings as appropriate. In addition, the same code | symbol is attached | subjected to the common part in each figure, and the overlapping description is abbreviate | omitted.

  The overall configuration, operation, function, and the like of the compressor 1 according to the present embodiment will be described with reference to FIGS.

  FIG. 1 is a schematic view of an air conditioner that is also used for air conditioning. In the air conditioner of this embodiment, the compressor 1, the outdoor heat exchanger 34, the expansion mechanism 35, and the indoor heat exchanger 36 are connected by piping, and the refrigerant circulates.

  In the case of the cooling operation, the high-temperature and high-pressure gas refrigerant compressed by the compressor 1 flows to the outdoor heat exchanger 34 through the four-way valve 33. The high-temperature and high-pressure gas refrigerant is cooled by the outdoor heat exchanger 34 functioning as a condenser, and becomes a high-pressure liquid refrigerant. The high-pressure liquid refrigerant is expanded by the expansion mechanism 35, becomes a low-temperature low-pressure liquid refrigerant containing a slight amount of gas, and flows to the indoor heat exchanger 36. The low-temperature and low-pressure liquid refrigerant is heated by the indoor heat exchanger 36 functioning as an evaporator, becomes a low-temperature gas refrigerant, and returns to the compressor 1 through the four-way valve 33 again. In the heating operation, the refrigerant flow is changed by the four-way valve 33, and the refrigerant flows in the opposite direction to the cooling operation.

  FIG. 2 is a longitudinal sectional view of the compressor. The compressor 1 is used as a constituent device of a refrigeration cycle such as a refrigeration air conditioner (for example, an air conditioner, a refrigerator, a freezer, a refrigeration / refrigeration showcase, etc.), a heat pump type hot water supply device, etc., and includes a hermetic container, a compression mechanism 2 and an electric motor. 7 as a main component. The compressor 1 of this embodiment is a hermetic electric compressor.

  The sealed container of the compressor 1 includes a cylindrical tube portion 1a, a lid portion 1b welded to the top and bottom of the tube portion 1a, and a bottom portion 1c, and the inside is a sealed space. The compressor 1 houses the compression mechanism 2 and the electric motor 7, and stores a lubricating oil 8 composed of an ether-based or ester-based refrigerator oil in an oil reservoir 9 at the bottom. The oil level of the lubricating oil 8 is set so as to be located above the auxiliary bearing 15.

  The compressor 1 is provided with a suction pipe 11 that penetrates the lid 1b of the sealed container and a discharge pipe 22 that penetrates the cylinder 1a of the sealed container. The discharge pipe 22 is located immediately below the frame 5 and is provided so as to protrude in the center direction in the sealed container of the compressor 1. The distal end of the discharge pipe 22 projects from the outer peripheral surface of the end coil 17 to the center side and opens.

  The compression mechanism 2 compresses the gas refrigerant and discharges it into the sealed container, and is installed in the upper part of the sealed container. The compression mechanism 2 includes a fixed scroll 3, a turning scroll 4, a frame 5, and an Oldham ring 10 as main components.

  The fixed scroll 3 is configured by standing a spiral wrap on the end plate, and is bolted on the frame 5. A suction port 12 is provided in the peripheral portion of the fixed scroll 3, and a discharge port 14 is provided in the central portion. The suction port 12 communicates with the suction pipe 11 and the discharge port 14 communicates with the space above the compression mechanism 2 in the sealed container.

  The orbiting scroll 4 is configured by standing a spiral wrap on the end plate, and the orbiting scroll 4 is sandwiched between the fixed scroll 3 and the frame 5. The orbiting scroll 4 and the fixed scroll 3 are engaged to form a compression chamber. On the side of the orbiting scroll 4 opposite to the fixed scroll, a boss portion into which the orbiting bearing is incorporated is provided. An eccentric pin portion 6a is fitted to the orbiting bearing to drive the orbiting scroll 4 eccentrically.

  The Oldham ring 10 constitutes a rotation restricting mechanism of the orbiting scroll 4 and is installed between the orbiting scroll 4 and the frame 5 to prevent the orbiting scroll 4 from rotating and to perform a circular orbit motion.

  The frame 5 is fixed to the sealed container by welding, and supports the fixed scroll 3, the Oldham ring 10, and the orbiting scroll 4. In the center of the frame 5, a cylindrical portion protruding downward is provided. A main bearing 5a that supports the shaft 6 is provided in the cylindrical portion.

  A plurality of discharge gas passages that connect the upper space of the fixed scroll 3 and the lower space of the frame 5 are formed in the outer peripheral portions of the fixed scroll 3 and the frame 5.

  The electric motor 7 includes a rotor 7a, a stator 7b, a shaft 6, and a balance weight 16 as main components.

  The stator 7b is used for insulation between the coil 24 having a plurality of conductors that cause a current to flow and generate a rotating magnetic field, an iron core 23 for efficiently transmitting the rotating magnetic field, and the coil 24 and the iron core 23. And a resin molded product insulator 26 as a main component. The coil 24 of the stator 7b is wound by a concentrated winding method.

  The iron core 23 is fixed to the sealed container by shrink fitting. A large number of notches are formed on the outer circumference of the stator 7b, and a discharge gas passage is formed between the notches and the sealed container.

  The rotor 7a includes a rotor iron core 25 and a permanent magnet built in the rotor iron core 25 as main components, and converts a rotating magnetic field from the stator 7b into a rotational motion and is rotated around the shaft 6. The The rotor 7a is rotatably disposed in the central hole of the iron core 23 of the stator 7b.

  The shaft 6 is fitted into the central hole of the rotor 7a and integrated with the rotor 7a. One side of the shaft 6 protrudes from the rotor 7 a and is engaged with the compression mechanism 2, and an eccentric force is applied by the compression operation of the compression mechanism 2. In the present embodiment, the shaft 6 protrudes from both sides of the rotor 7a, is supported by the main bearing 5a and the auxiliary bearing 15 on both sides of the rotor 7a, and can rotate stably. The auxiliary bearing 15 is supported by a support member fixed by welding to the sealed container of the compressor 1 and is immersed in the lubricating oil 8.

  The lower end of the shaft 6 extends into the oil sump 9 at the bottom of the hermetic container of the compressor 1. The shaft 6 is provided with through holes 6b for supplying the lubricating oil 8 to the bearings and the sliding surfaces, and the lubricating oil 8 can be sucked up from the through holes 6b from the oil reservoir 9 at the lower end. Lubricating oil 8 sucked into the compression mechanism 2 from the oil reservoir 9 through the shaft through hole 6 b is supplied to each bearing and the sliding portion of the compression mechanism 2. The lubricating oil 8 supplied to the sliding portion of the compression mechanism 2 is discharged from the discharge port 14 at the center of the fixed scroll 3 together with the refrigerant gas.

  The balance weight 16 is a balance weight (hereinafter referred to as “upper balance weight”) 16a installed on the compression mechanism 2 side of the rotor 7a and a lower balance weight (hereinafter referred to as “compression mechanism 2”) of the rotor 7a. It is composed of 16b and is fixed to the rotor 7a by a plurality of rivets.

  When the electric motor 7 is energized and the rotor 7a rotates, the shaft 6 is also rotated accordingly, and the eccentric pin portion 6a performs an eccentric rotational motion, whereby the orbiting scroll 4 is driven to rotate, and the fixed scroll 3 and the orbiting scroll. 4, the compression chamber formed between the outer peripheral side and the central portion becomes smaller while moving. Thereby, the refrigerant gas sucked from the outside of the hermetic container of the compressor 1 through the suction pipe 11 and the suction port 12 is compressed by the compression mechanism 2, and the compressed refrigerant gas is discharged from the central portion of the fixed scroll 3. 14 is discharged into the upper space in the sealed container of the compressor 1.

  The stator 7 b includes a stator iron core 23, an insulator 26 disposed opposite to both end surfaces of the stator iron core 23 in the axial direction, and a coil wound around the stator iron core 23 and the insulator 26. 24.

  FIG. 3 is a perspective view of the stator core. As shown in FIG. 3, the stator core 23 is composed of a plurality of laminated steel plates, and protrudes radially inward from the stator core annular portion 27 and the inner peripheral surface of the stator core annular portion 27. In addition, there are teeth portions 28 arranged at equal intervals in the circumferential direction.

  The electric motor 7 has a so-called 4-pole 6-slot, and employs a so-called concentrated winding method in which the coil 24 is intensively wound around one tooth portion 28 without spanning the plurality of tooth portions 28.

  4 is a bottom view of the insulator, and FIG. 5 is a perspective view of the insulator. The insulator 26 is sandwiched between the stator iron core 23 and the coil 24 to insulate the stator iron core 23 from the coil 24. The insulator 26 is made of, for example, a resin material with good heat resistance such as liquid crystal polymer (LCP), polybutylene terephthalate (PBT), polyphenylene sulfide (PPS), polyimide, or polyester. Further, the insulator 26 is made of a material containing glass fiber, for example, for improving the strength.

  The dielectric constant of liquid crystal polymer (LCP) is 3.6, the dielectric constant of polybutylene terephthalate (PBT) is 3.1 to 3.3, and the dielectric constant of polyphenylene sulfide (PPS) is 2.8.

  As shown in FIGS. 4 and 5, the insulator 26 includes an insulator annular portion 29, and a plurality of body portions 30 that protrude radially inward from the inner peripheral surface of the insulator annular portion 29 and are arranged at equal intervals in the circumferential direction. have.

  The insulator annular portion 29 of the insulator 26 is disposed so as to be in contact with both end surfaces of the stator core annular portion 27 of the stator iron core 23, and the plurality of trunk portions 30 of the insulator 26 include the plurality of the stator iron core 23. It arrange | positions so that the both end surfaces of the teeth part 28 may be contact | connected. In other words, the stator core 23 is sandwiched between the two insulators 26 from the bearing direction.

  The insulator annular portion 29 is not chamfered at both ends in the circumferential direction on the surface in contact with the stator core 23, and is chamfered at both ends in the circumferential direction on the surface opposite to the stator core 23.

  The compressor 1 is driven by rotating the rotor 7 a together with the shaft 6 by an electromagnetic force generated in the stator 7 b by passing an electric current through the coil 24. A part of the current flowing through the coil 24 leaks to the stator core 23.

  Here, in the compressor 1, since the stator is directly fixed to the airtight container made of a steel plate, the values specified in the Electrical Appliance and Material Control Law (the charging unit and the surface of the container body and the like so as not to affect the human body). The leakage current flowing during the period must be within 1 mA). Therefore, it is necessary to take measures so that the leakage current leaking to the stator core 23 out of the current flowing through the coil 24 is 1 mA or less.

The principle of the leakage current is the same as that of the capacitor. When the leakage current is i, the frequency is f, the floating capacitance is C, and the voltage is V, the relationship of Expression (1) is established.
[Equation 1]
i = 2πfCV (1)
The stray electrostatic capacitance C between the coil 24 and the stator core 23 is ε as the relative dielectric constant between the coil 24 and the stator core 23, and the area between the coil 24 and the stator core 23. Is S, and the distance between the coil 24 and the stator core 23 is d, the relationship of Expression (2) is established.
[Equation 2]
C = εS / d (2)
[Dielectric constant of R32]
By the way, compared with R410A, R32, which has a low global warming potential and is studied as a candidate for a next-generation refrigerant, has a high relative dielectric constant ε. For example, the relative dielectric constant ε of R410A at 40 ° C. is 7.7045, whereas the relative dielectric constant ε of R32 at 40 ° C. is 11.268.

  That is, when R32 is adopted as the refrigerant, the floating capacitance C becomes larger than that in the equation (2). Then, there is a possibility that the leakage current i exceeds the value specified in the Electrical Appliance and Material Control Law from Equation (1).

  Leakage current i can be reduced by sandwiching the insulating material 32 between the coil 24 and the stator core 23. However, when R32 is adopted as the refrigerant, the leakage current i cannot be kept below the value defined in the Electrical Appliance and Material Control Law with the insulating material 32 that is currently widely used. The thickness of the insulating material 32 that is currently widely used is 3 mm at the maximum. However, if the thickness is thicker than 3 mm or two insulating materials 32 are used in layers, the cost is high and the assemblability is deteriorated.

  FIG. 6 is a cross-sectional view in the circumferential direction of the teeth portion of the stator core and the trunk portion of the insulator. The coil 24 is wound around the teeth portion 28 of the stator core 23 and the trunk portion 30 of the insulator 26 by a winding machine.

  Conventionally, the teeth 24 of the coil 24 and the stator core 23 are in close contact with each other. On the other hand, in the present embodiment, as shown in FIG. 6, the circumferential width of the trunk portion 30 of the insulator 26 is made larger than the circumferential width of the teeth portion 28 of the stator core 23. By winding the coil 24 around the stator core 23 and the insulator 26, the coil 24 does not contact the stator core 23, and a gap 31 is provided between the stator core 23 and the coil 24. it can.

  According to the present embodiment, by securing the distance d between the coil 24 and the stator core 23 by the gap 31, the floating capacitance C is made smaller than the formula (2), and the leakage current is calculated from the formula (1). i can be made equal to or less than the value specified in the Electrical Appliance and Material Control Law.

  The teeth portion 28 of the stator core 23 and the body portion 30 of the insulator 26 have substantially the same shape except for the width in the circumferential direction when viewed from the axial direction of the stator core 23 (the rotational axis direction of the shaft 6). . However, in order to prevent the deterioration of the coil 24, a portion of the body portion 30 of the insulator 26 that is discharged in the circumferential direction from the teeth portion 28 of the stator core 23 has an elliptical shape.

  Further, R32 and refrigerating machine oil are collected in the gap 31. By disposing the insulating material 32 having a dielectric constant lower than that of R32 and refrigerating machine oil in a part of the gap 31, the average value of the relative dielectric constant ε in the gap 31 can be lowered, and the leakage current i can be further reduced. it can.

  Further, in addition to making the circumferential width of the body portion 30 of the insulator 26 larger than the circumferential width of the teeth portion 28 of the stator iron core 23, the coil 24 is interposed between the stator core 23 and the coil 24. Arranging the insulating material 32 may be used in combination.

  Further, in addition to making the circumferential width of the trunk portion 30 of the insulator 26 larger than the circumferential width of the teeth portion 28 of the stator iron core 23, the inner circumferential surface of the insulator annular portion 29 is made the stator iron. The core annular portion 27 may be protruded inward in the radial direction from the inner peripheral surface.

  As described above, according to the present embodiment, the distance between the coil 24 and the stator core 23 can be increased, the stray capacitance C can be reduced, and the effect of reducing leakage current can be obtained.

  In the present embodiment, description of the same components as those in the first embodiment is omitted. FIG. 7 is an explanatory diagram of folded portions at both ends of the insulating material. FIG. 8 is a cross-sectional view in the circumferential direction of the teeth portion of the stator core and the trunk portion of the insulator.

  As shown in FIG. 7, the insulating material 32 of the present embodiment has a folded portion 32 a in which both ends in the bearing direction are folded. That is, at both ends of the stator iron core 23 in the bearing direction, the insulating material 32 is folded and overlapped so as to be disposed between the stator iron core 23 and the coil 24 in the radial direction.

  Although the insulating material 32 of this embodiment is one piece, since the coil 24 is supported by the folded portion 32a of the insulating material 32, the distance d between the coil 24 and the stator core 23 is insulated even near the center. The thickness of the material 32 can be doubled.

  According to the present embodiment, as shown in FIG. 8, in addition to disposing the insulating material 32 between the coil 24 and the stator iron core 23, the gap 31 between the stator iron core 23 and the insulating material 32. Can be provided. Therefore, by folding back the insulating material 32 and securing the distance d between the coil 24 and the stator core 23, the floating capacitance C is made smaller than the equation (2), and the leakage current i is calculated from the equation (1). Can be reduced.

  In this embodiment, as shown in FIG. 8, the folded portion 32 a of the insulating material 32 is positioned closer to the stator core 23 than the coil 24, but the folded portion 32 a of the insulating material 32 is located on the coil 24 side. May be located.

  However, when the folded portion 32 a of the insulating material 32 is positioned on the coil 24 side, the gap 31 is positioned between the coil 24 and the insulating material 32 near the center. Since the refrigerant accumulates in the gap 31, current easily leaks from the coil 24 to the refrigerant.

  On the other hand, when the folded portion 32a of the insulating material 32 is positioned on the stator iron core 23 side, the gap 31 is positioned between the fixed iron core 23 and the insulating material 32 as shown in FIG. That is, since the gap 31 is in contact with the coil 24 via the insulating material 32, current leakage from the coil 24 to the refrigerant accumulated in the gap 31 can be reduced.

  Further, the distance d between the coil 24 and the stator core 23 may be secured by increasing the thickness in the circumferential direction of the stator core 23 at both ends of the stator core 23 in the bearing direction.

  As described above, according to the compressor of the present invention, the distance between the coil 24 and the stator core 23 can be increased, the stray capacitance C can be reduced, and the leakage current reduction effect can be obtained.

  The present invention is not limited to the above-described embodiments, and includes various modifications. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Further, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

  For example, as the compression mechanism 2, a rotary type, a swing type, or a reciprocating type may be used in addition to the scroll type.

  Moreover, although the case where R32 was used as a refrigerant | coolant was demonstrated, it is not restricted to this. For example, as the refrigerant, a mixed refrigerant containing more than 50% by weight of R32 or other refrigerants requiring countermeasures against leakage current may be used.

DESCRIPTION OF SYMBOLS 1 Airtight container 7 Electric motor 7a Rotor 7b Stator 8 Lubricating oil 9 Oil reservoir 23 Stator iron core 25 Rotor iron core 24 Coil 26 Insulator 27 Stator iron core annular part 28 Teeth part 29 Insulator annular part 30 Trunk part 31 Crevice 32 Insulating material 32a Folding portion 33 Four-way valve 34 Outdoor heat exchanger 35 Expansion mechanism 36 Indoor heat exchanger

Claims (5)

In an electric motor stored in an airtight container together with a compression mechanism and a lubricating oil for compressing and discharging a refrigerant,
A stator core,
Insulators disposed at both ends of the stator core in the bearing direction;
A coil wound in a concentrated winding manner on the stator core and the insulator;
An insulating material disposed between the stator core and the coil;
Comprising a stator having
The stator iron core includes a stator iron core annular portion and a plurality of teeth portions protruding radially inward from an inner peripheral surface of the stator iron core annular portion,
The insulator includes an insulator annular portion, and a plurality of trunk portions protruding radially inward from an inner peripheral surface of the insulator annular portion,
The circumferential width of the body portion is larger than the circumferential width of the teeth portion,
The coil is wound around the body portion and the teeth portion, thereby providing a gap between the coil and the stator iron core,
The insulating material is disposed in a part of a gap between the coil and the stator iron core,
The coil and the insulating material are in contact with each other,
The distance between the coil and the stator iron core is longer than the thickness of the insulating material, and there is a gap between the stator iron core and the insulating material, and the stator iron core and the insulating material Refrigerant and refrigeration oil accumulate in the gap between
The electric motor characterized by the dielectric constant of the said insulating material being lower than the dielectric constant in the clearance gap between the said coil and the said stator core. In an electric motor stored in an airtight container together with a compression mechanism and a lubricating oil for compressing and discharging a refrigerant,
A stator core,
Insulators disposed at both ends of the stator core in the bearing direction;
A coil wound in a concentrated winding manner on the stator core and the insulator;
An insulating material disposed between the stator core and the coil;
Comprising a stator having
The stator iron core includes a stator iron core annular portion and a plurality of teeth portions protruding radially inward from an inner peripheral surface of the stator iron core annular portion,
The insulator includes an insulator annular portion, and a plurality of trunk portions protruding radially inward from an inner peripheral surface of the insulator annular portion,
The circumferential width of the body portion is larger than the circumferential width of the teeth portion,
The coil is wound around the body portion and the teeth portion, thereby providing a gap between the coil and the stator iron core,
The insulating material is disposed in a part of a gap between the coil and the stator iron core,
The inner peripheral surface of the insulator annular portion protrudes radially inward from the inner peripheral surface of the stator core annular portion,
The coil and the insulating material are in contact with each other,
The distance between the coil and the stator iron core is longer than the thickness of the insulating material, and there is a gap between the stator iron core and the insulating material, and the stator iron core and the insulating material Refrigerant and refrigeration oil accumulate in the gap between
The electric motor characterized by the dielectric constant of the said insulating material being lower than the dielectric constant in the clearance gap between the said coil and the said stator core. The electric motor according to claim 1, wherein a thickness of the insulating material is 3 mm or less. A hermetic compressor having the electric motor according to any one of claims 1 to 3, a condenser, an expansion valve, and an evaporator are sequentially connected in an annular manner, and a refrigerant circuit through which a refrigerant flows is provided.
The air conditioner, wherein the refrigerant is R32 or a mixed refrigerant containing more than 50% by weight of R32. The stator is fixed to the closed container of the hermetic compressor,
5. The air conditioner according to claim 4, wherein a current leaking to the stator core is equal to or less than a value defined in the Electrical Appliance and Material Control Law.