US20120301334A1

US20120301334A1 - Compressor and Refrigerating Cycle Apparatus

Info

Publication number: US20120301334A1
Application number: US13/479,438
Authority: US
Inventors: Baiying Huang; Hiroyasu Yoneyama; Kazuo Sakurai
Original assignee: Hitachi Appliances Inc
Current assignee: Hitachi Appliances Inc
Priority date: 2011-05-27
Filing date: 2012-05-24
Publication date: 2012-11-29
Also published as: JP2012246819A; CN102797675A

Abstract

In a conventional compressor, since a motor and a mechanical section of the compressor are disposed in one and the same closed container, the motor is exposed to high-temperature coolant and heated, and the efficiency of the motor is lowered. Further, during the operation of the compressor, the coolant circulating in the refrigerating cycle conveys additional heat generated by the motor coil. Thus the efficiency of the refrigerating cycle is lowered. The compressor according to the present invention includes a compression chamber divided into a closed chamber and an open chamber separated by a magnetic induction plate from each other. The closed chamber is filled with high temperature and pressure coolant and the rotor of the motor is disposed in the closed chamber, and the stator of the motor is disposed in the open chamber.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Japanese Patent Application No. 2011-118603 filed on May 27, 2011, the disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention
The present invention relates to an axial gap motor and a compressor using the same.
2. Description of the Related Art
In a conventional type compressor having an axial gap motor as disclosed in Japanese Laid-Open Patent Application Publication No. 2007-32429 for example (to be referred to as Patent Document 1 hereinafter), an axial gap motor and a compression mechanism section are disposed in one and the same closed container. The abovementioned axial gap motor is disposed in low-pressure coolant suctioned in a refrigeration cycle. By the rotation of the rotor, the coolant is sent to a stator, and then flown into the compression mechanism section to be compressed.
This configuration has an advantage that a liquid droplet or an oil droplet contained in the coolant is separated, and liquid compression can be avoided effectively.
However, in the abovementioned configuration of the compressor, the motor and the compression mechanism section are disposed in the same closed container. Therefore, the motor is exposed to high-temperature coolant and heated, and the efficiency is lowered. Further, during the operation of the compressor, the coolant circulating during the refrigerating cycle conveys additional heat generated by the motor coil. Thus the efficiency of the refrigerating cycle is lowered.
In light of the above, an objective of the present invention is to provide a highly-efficient compressor and a refrigerating cycle apparatus equipped with the same.

SUMMARY OF THE INVENTION

The objective of the present invention above is achieved by a compressor including an axial gap motor for driving the compressor, the axial gap motor having a stator and a rotor, the stator having a plurality of small stators each having a small stator core, the small stator core being made of magnetic steel sheet and having a wire wound therearound, the rotor having a magnet facing to the stator, wherein the stator is disposed outside of a closed chamber, the rotor is connected to a mechanical section of the compressor, and the compressor is driven by magnetic induction therebetween.
In addition, the objective of the present invention above is achieved by a high-pressure chamber compressor including a compression chamber, a compression mechanism section including a motor is disposed in the compression chamber, rotation of a rotor of the motor compressing coolant at high temperature and pressure, wherein the high temperature and pressure coolant fills up the compression chamber and is discharged thereafter, the motor is an axial gap motor, the compression chamber further includes a closed chamber and an open chamber separated by a magnetic induction plate, the closed chamber is filled with the high temperature and pressure coolant, and the rotor is disposed in the closed chamber.
According to the present invention, it is possible to provide a highly-efficient and highly-reliable compressor with a simple configuration.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-section outline drawing illustrating a compressor driven by an axial gap motor according to a first embodiment of the present invention;

FIGS. 2A and 2B are a structural outline drawing illustrating a rotor of the axial gap motor according to the first embodiment of the present invention;

FIGS. 3A to 3D are structural outline drawings illustrating cross-sections of a magnetic induction member according to the first embodiment of the present invention;

FIGS. 4A to 4D are outline drawings illustrating a stator of the axial gap motor according to the first embodiment of the present invention;

FIG. 5 is a cross-section outline drawing illustrating a stator of the axial gap motor according to the first embodiment of the present invention;

FIG. 6 is a cross-section outline drawing illustrating a compressor driven by an axial gap motor according to a second embodiment of the present invention;

FIGS. 7A to 7C are structural outline drawings illustrating cross-sections of a magnetic induction member according to the second embodiment of the present invention;

FIG. 8 is a cross-section outline drawing illustrating a compressor driven by an axial gap motor according to a third embodiment of the present invention; and

FIG. 9 is an outline drawing illustrating a refrigerating cycle of an air conditioner according to the fourth embodiment of the present invention.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENT

Embodiments of the present invention will be explained next in detail with reference to the related drawings according to the necessity.

Embodiment 1

FIG. 1 is a cross-section outline drawing illustrating a compressor driven by an axial gap motor according to a first embodiment of the present invention. Embodiment 1 will be explained with reference to FIGS. 1 to 5.
In FIG. 1, a compressor 82 is configured with a closed chamber 69 having a coolant compression mechanism section and a stator chamber 79 having a stator 2 which constitutes an axial gap motor, and the closed chamber 69 and the stator chamber 79 are separated from each other by a magnetic induction plate 50. The compression mechanism section is configured by engaging a spiral wrap 62 and a spiral wrap 65, the spiral wrap 62 standing erect on an end plate 61 of a fixed scroll member 60, and the spiral wrap 65 standing erect on an endplate 64 of a turn scroll member 63. The fixed scroll member 60 is press fitted into a casing of the compressor and fixed by welding. Then compression of the coolant is performed by making the turn scroll member 63 turn via a crankshaft 4.
Each of compression spaces 66 (66 a, 66 b . . . ) is defined by the fixed scroll member 60 and the turn scroll member 63. The outermost compression space 66 moves inward toward the center of the scroll members 60 and 63 along with the turning motion and the volume is reduced gradually. When the compression space 66 (66 a, 66 b . . . ) reaches near the center of the scroll members 60 and 63, compressed coolant is discharged from a discharge hole 67. Discharged gas comes into a closed chamber 69 located on a lower portion of a frame 68 by way of a gas passage (not shown) disposed in the fixed scroll member 60 and the frame 68, and then discharged via a discharge pipe 70 disposed on a side wall of the closed chamber 69 to outside the compressor.
Each of the closed chamber 69, the turn scroll member 63 and the rotor 3 is connected to the crankshaft 4. While the rotor 3 is rotating, the turn scroll member 63 is turning also with the rotation of the crankshaft 4, thereby compressing the coolant. An oil-retaining space 71 is disposed at the bottom of the closed chamber 69. Due to pressure difference between a back-pressure room and the closed chamber 69, oil in the oil-retaining space 71 is sent through an oil gallery 72 in the crankshaft 4 and supplied for lubrication of the slide portion of the turn scroll member 63 and the crankshaft 4, and slide bearing 73 etc.
FIGS. 2A and 2B are an outline drawing illustrating a rotor 3, and the rotor 3 is made of nonmagnetic material (metal, or possibly non-metal). Permanent magnets 17 are fixed to the disc-shaped rotor 3 with adhesive, and then magnetized such that adjacent magnets having opposite polarity by applying pulse current using a magnetizing device. The permanent magnet 17 may be made of ferrite or possibly rare earth magnet. The shape thereof may be roughly fan-shaped (possibly rectangle, square, oval, circle etc.), and the thickness thereof may be even (or possibly uneven).
FIGS. 3A to 3D are outline drawings illustrating cross-sections of a magnetic induction plate 50. FIG. 3B shows a cross-section in an axial direction, and FIGS. 3A, 3C and 3D show a cross-section in an a radial direction. The magnetic induction plate 50 includes a non-magnetic metal disc 51 having an external diameter slightly smaller than the inner diameter of the closed chamber 69 (thickness is 5 to 15 mm, material is stainless etc.), and a plurality of magnetic bodies 52 a (magnetic steel sheet, amorphous material, powder magnetic core etc.). On the non-magnetic metal disc 51, holes 52 of the same number of pieces and roughly same size as a small stator 16 are formed in a shape of annular array and a plurality of magnetic bodies 52 a are fixed by welding for example.
Here, the magnetic body 52 a may be configured to have a shape shown in FIG. 3C or 3D. The magnetic induction plate 50 is welded to a casing 18 of the compressor such that the magnetic induction plate 50 separates the closed chamber 69 from the stator chamber 79. In other words, in this compressor, the high-pressure chamber filled with high-pressure coolant gas and the stator chamber 79 in which the stator of the motor is disposed are separated by the magnetic induction plate 50.
In the stator chamber 79, the stator 2 of the axial gap motor is configured by setting and molding a plurality of small stators 16 and a magnetic induction end plate 7 on a holder 8. Then it is fixed to the casing 18. The stator 2 is press-fitted to the stator chamber 79, and then fixed with an air gap of 0.3 to 1.5 mm from the magnetic induction plate 50. The lead line of the coil passes through a hole 92 on the stator chamber 79 and is connected to a terminal block 91. For avoiding dust etc. from coming in, a cover 31 is attached on the casing 18 of the compressor with volts.
FIGS. 4A to 4D are outline drawings illustrating a small stator 16 of the axial gap motor.
As shown in FIG. 4A, a unit of a member 11, which is made of nonmagnetic material, having a constant length, and is roughly fan-shaped (possibly rectangle, square, oval, circle etc.), is made by plastic molding or the like. Then amorphous ribbon having one-side insulating coating is wound around the member 11. Upon reaching a predetermined size, the amorphous ribbon is cut off, the member 11 is hardened with adhesive or plastic coating, or the stator core is fixed by an insulating paper 13 with adhesive. Thus the small stator core 14 made of amorphous material, as shown in a cross-section shown in FIG. 4B, is produced.
Alternatively, as shown in FIG. 4C, the small stator core 14 a can be made by laminating a magnetic steel sheet, and coating the outer periphery with insulating material such as plastic. Further, a coil 15 is wound around the small stator core 14 (or 14 a), end wires 15 a and 15 b of the coil 15 are lead out, and thus the small stator 16 is formed as shown in FIG. 4D.
FIG. 5 is a sectional view in an axial direction of the stator. As shown in the figure, holes 20 are made on the periphery of the holder 8 with constant distance apart from each other, and then a plurality of the small stators 16 are mounted and fixed to the holes 20. The number of the small stators 16 is 3n (here, n represents natural numbers). End wires of the three-phase coil (U, V, W) are made by connecting the end wires 15 a and 15 b of the small stator 16. Then the plastic is flown and the integrated stator 2 is molded.
Next, the rotor 3 and the stator 2 are formed such that the magnetic induction plate 50 is disposed therebetween. The axial gap motor is formed such that a plurality of magnetic bodies 52 a is disposed with an air gap to the rotor 3 on both sides thereof including a plurality of permanent magnets 17 attached on the rotor 3 and the stator 2. The gap of the axial gap motor is 0.3 mm to 1.5 mm. Although the gap is the smaller the better, since the magnetic induction plate 50 takes a roll of a partition, it is necessary to make consideration about deformation volume thereof.
To partition the chamber of the whole compressor 82 into the closed chamber 69 and the stator chamber 79, the magnetic induction plate 50 is used as a partition. The magnetic induction plate 50 takes this role. Not only separating the chamber, it is also necessary to transfer the rotating magnetic field of the stator 2 to the rotor 3. A magnetic body 52 a(c, d) on the magnetic induction plate 50 takes this role. Thus, for improving the efficiency of the compressor, a magnetic induction member is provided on both end faces of the axial gap motor in an axial direction of the stator, and the compressor is driven by the magnetic induction. Maintenance can be improved as the stator 2 is disposed outside the closed chamber 69.
Next, the operation of the axial gap motor will be explained. In the stator 2, a three-phase coil is provided on each of the small stators 16. Rotating magnetic field can be generated by controlling current of an inverter in an axial direction on both end faces of the stator 2. The flux reaches to a plurality of permanent magnet 17 on the rotor 3 disposed in the closed chamber 69 by way of the magnetic body 50 which is a magnetic inductor, and then magnetic attraction or magnetic repulsion is generated between the magnetic body 52 a(c, d) and the permanent magnet 17. The rotor 3 rotates synchronously with the rotating magnetic field. Then the turn scroll member 63 which is connected to the crankshaft 4 also rotates in conjunction with the rotor 3, thereby operating the compressor.
To improve reliability of the coil, the rotor 3 may be magnetized using a dedicated yoke tool, and then connected to the mechanical section of the compressor.
To prevent flux from leaking, one of end faces of the stator 2 is provided with a magnetic disc 7. The magnetic disc 7 is made of a magnetic body such as a magnetic steel sheet, annular-shaped, and the area in a radial direction covers a plurality of small stators 16. In addition, the flux generated from a plurality of the small stators 16 is guided to the magnetic body 52 a. Thus leakage of the flux is reduced and the efficiency of the motor is improved.
Although the stator of the motor in the present embodiment comprises 12-pole and the rotor comprises 8-pole, the stator 2 and the rotor 3 may be configured to have another combination of pole numbers.
Thus, by making the compressor driven with magnetic induction using the axial gap motor described in FIGS. 1 to 4, it is possible to achieve a high efficiency compressor without affection of heat generated by the motor coil in the refrigerating cycle. In addition, reliability and maintenance of the compressor can be improved.

Embodiment 2

FIG. 6 is a cross-section outline drawing illustrating a compressor driven by an axial gap motor according to a second embodiment of the present invention. FIG. 7B is a cross-section in an axial direction of a magnetic induction member according to the second embodiment. FIGS. 7A and 7C are cross-sections in a radial direction of a magnetic induction member according to the second embodiment.
In the explanation of embodiment 2 according to the present invention, redundant descriptions of the compression mechanism section same as embodiment 1 may be omitted, and different portions of the axial gap motor will be explained. The magnetic induction plate 50 is configured with a disc 51 made of nonmagnetic material and having an outer diameter slightly smaller than the inner diameter of the closed chamber 69 (e.g. 5 to 10 mm in thickness, made of stainless), and a plurality of magnetic bodies 52 e (e.g. magnetic steel sheet, powder magnetic core). On the disc 51, holes 52 of the same number and roughly same size as the small stator cores 14 a (or 14) are formed in a shape of annular array and a plurality of magnetic bodies 52 e are fixed by welding as shown in FIG. 7C. Then a plurality of the magnetic bodies 52 e are coated with insulating material such as plastic, and then the coil 15 is wound therearound. Thus, a component integrating small stators 16 and the magnetic induction plate 50 are formed, and a magnetic induction component 54 having the stator 2 integrated by plastic molding is produced.
Further, the magnetic induction component 54 having the stator is mounted to the casing of the compressor 82 with a constant air gap of 0.3 mm to 1.5 mm. In the configuration shown in FIG. 7, the gap is the smaller the better as there is almost no bending of the nonmagnetic plate 51.
According to this configuration, when current is applied to each of the three-phase coils of the small stators 16 during operation of the compressor, rotating magnetic field is generated from coil wound around the small stator core. The flux reaches the permanent magnet 17 of the rotor 3 disposed in the closed chamber via the small stator 52 e. The rotor 3 rotates synchronously with the rotating magnetic field by the magnetic attraction or magnetic repulsion between the rotating magnetic field and the permanent magnet 17. Then the turn scroll member 63 which is connected to the crankshaft 4 also rotates, thereby operating the compressor.
As a plurality of the small stators 16 and the magnetic induction plate 50 are integrated, magnetic resistance of the flux path is considerably reduced, and the flux is prevented from leaking. Embodiment 2 receives full benefit of Embodiment 1, and in addition, the efficiency of the motor is considerably improved.
Thus there is provided an efficient compressor driven by magnetic induction in which the stator core of the axial gap motor is integrated with a magnetic induction member for improving efficiency.

Embodiment 3

FIG. 8 is a cross-section outline drawing illustrating a compressor driven by an axial gap motor according to a third embodiment of the present invention.
As shown in FIG. 8, the compressor according to Embodiment 3 includes two closed chambers 69 arranged on both end faces with an air gap of 0.3 mm to 1.5 mm. The closed casing 18 of the compressor and the casing 19 of the axial gap motor are fixed using volts.
In the present embodiment, since the configuration of the closed chamber 69 having coolant compression mechanism section is same as the Embodiments 1 and 2, the redundant explanation will be omitted. The stator 2 a of the axial gap motor according to the present embodiment is not provided with a magnetic disc 7. Other components are the same as those of the stator 2 and disposed in the stator chamber 79.
When current is applied to the three-phase coil of the stator 2 a, a rotating magnetic field is generated on both end faces of the stator 2, and attraction or repulsion force is generated relative to the rotors 3 disposed on both sides of the stator 2. As a result, the rotors 3 rotate at the same time by the induction of the rotating magnetic field. Then the turn scroll member 63 fixed on the crankshaft 4 also turns in conjunction with the rotation of the rotors 3 thereby performing compression operation of the coolant.
As described above, for improving efficiency of the compressor, a magnetic induction member is provided on both end faces in an axial direction of the axial gap motor, and the compressor is driven by magnetic induction. According to the configuration above, the compressor of Embodiment 3 receives full benefit of Embodiments 1 and 2, and in addition, a compressor having capacity larger than Embodiments 1 and 2 can be achieved.

Embodiment 4

FIG. 9 is an outline drawing illustrating a refrigerating cycle of an air conditioner according to a fourth embodiment of the present invention. In FIG. 9, a symbol 80 represents outdoor equipment and a symbol 81 represents indoor equipment. A compressor 82 is filled with coolant. A condenser 84, an expansion valve 85, and an evaporator 86 are connected via pipes. Each of the outdoor equipment 80 and the indoor equipment 81 is provided with a fan 88 and a motor. The fan is rotated by operation of the compressor 82, and heat exchange is performed between the coolant in the cooling unit and surrounding air. Due to the refrigerating cycle, the coolant is circulated in a direction indicated with the arrows. The compressor 82 compresses the coolant, performs heat exchange between the outdoor equipment 80 and the indoor equipment 81, thereby performing cooling operation. By providing a four-way valve (not shown) and reversing the direction of the refrigerating cycle, heating operation can be performed. When the operation is reversed between cooling and heating, the relation between the condenser 84 and the evaporator 86 is also reversed.
By applying a compressor using an axial gap motor explained in the embodiments to an air conditioner, freezing and refrigeration cycle apparatus etc., efficiency of the compressor can be improved and running costs can be reduced. In addition, since the stator is not exposed to high temperature and pressure coolant during the operation of the compressor, reliability can be improved with respect to insulation of the coil or aging degradation. Further, since the motor is disposed in a room separated from the closed chamber, maintenance of the motor becomes easy.

Claims

1. A compressor comprising:

an axial gap motor including a rotor and a stator; and

a coolant compression mechanism section disposed in a closed chamber and connected to the rotor of the axial gap motor via a crankshaft, wherein

the stator of the axial gap motor is disposed outside of the closed chamber, and the coolant compression mechanism section of the compressor is driven by magnetic induction therebetween.

2. The compressor according to claim 1,

wherein one of the coolant compression mechanism sections disposed on one side of the stator is driven by magnetic induction.

3. The compressor according to claim 1,

wherein two of the coolant compression mechanism sections disposed on both sides of the stator is driven by magnetic induction.

4. The compressor according to claim 1,

wherein a nonmagnetic metal plate is provided between the stator and the rotor of the axial gap motor, and the nonmagnetic metal plate is welded to a casing of the compressor.

5. The compressor according to claim 4 further comprising:

a plurality of small stator cores on both sides of a plane of the nonmagnetic metal plate, each projecting from either side of the plane of the magnet metal plate; and one or more magnetic inductors on the nonmagnetic metal plate, number and shape thereof being same as that of the small stator cores of the stator.

6. The compressor according to claim 4 further comprising:

a plurality of small stator cores on both sides of a plane of the nonmagnetic metal plate, each projecting on either side of the plane of the magnet metal plate; and

a coil being disposed on one side of each of a plurality of the small stator cores.

7. The compressor having an axial gap motor according to claim 1,

wherein the rotor is disposed on one side of end faces of the stator of the axial gap motor and an annular magnetic plate is disposed on the other side of end faces of the stator.

8. A high pressure chamber compressor comprising:

a motor including a rotor and a stator; and

a compression mechanism disposed in a compression chamber,

wherein

coolant is compressed by the compression mechanism via rotation of the rotor at high temperature and pressure, the coolant fills the compression chamber and is discharged thereafter,

the motor is an axial gap motor,

the compression chamber is partitioned into a closed chamber and an open chamber separated with a magnetic induction plate from each other, the closed chamber is filled with high temperature and pressure coolant and the rotor of the motor is disposed in the closed chamber, and the stator of the motor is disposed in the open chamber.

9. The high pressure chamber compressor according to claim 8, wherein the magnetic induction plate includes:

a nonmagnetic metal disc fixed on the compression chamber; and

a magnetic body transferring rotating flux from the stator to the rotor and press fitted into the nonmagnetic metal disc.

10. The high pressure chamber compressor according to claim 8,

wherein the magnetic induction plate includes:

a nonmagnetic metal disc fixed on the compression chamber; and

a magnetic body constituting a part of the stator and press fitted into the nonmagnetic metal disc.

11. A refrigerating cycle apparatus including the compressor according to claim 1, wherein coolant is circulated during a refrigerating cycle by operation of the compressor.

12. A refrigerating cycle apparatus including the compressor according to claim 2, wherein coolant is circulated during a refrigerating cycle by operation of the compressor.

13. A refrigerating cycle apparatus including the compressor according to claim 3, wherein coolant is circulated during a refrigerating cycle by operation of the compressor.

14. A refrigerating cycle apparatus including the compressor according to claim 4, wherein coolant is circulated during a refrigerating cycle by operation of the compressor.

15. A refrigerating cycle apparatus including the compressor according to claim 5, wherein coolant is circulated during a refrigerating cycle by operation of the compressor.

16. A refrigerating cycle apparatus including the compressor according to claim 6, wherein coolant is circulated during a refrigerating cycle by operation of the compressor.

17. A refrigerating cycle apparatus including the compressor according to claim 7, wherein coolant is circulated during a refrigerating cycle by operation of the compressor.

18. A refrigerating cycle apparatus including the compressor according to claim 8, wherein coolant is circulated during a refrigerating cycle by operation of the compressor.

19. A refrigerating cycle apparatus including the compressor according to claim 9, wherein coolant is circulated during a refrigerating cycle by operation of the compressor.

20. A refrigerating cycle apparatus including the compressor according to claim 10, wherein coolant is circulated during a refrigerating cycle by operation of the compressor.