CN100427757C - Hermetic compressor - Google Patents
Hermetic compressor Download PDFInfo
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- CN100427757C CN100427757C CNB2005800009645A CN200580000964A CN100427757C CN 100427757 C CN100427757 C CN 100427757C CN B2005800009645 A CNB2005800009645 A CN B2005800009645A CN 200580000964 A CN200580000964 A CN 200580000964A CN 100427757 C CN100427757 C CN 100427757C
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- 230000004907 flux Effects 0.000 claims abstract description 61
- 230000006835 compression Effects 0.000 claims description 34
- 238000007906 compression Methods 0.000 claims description 34
- 230000004323 axial length Effects 0.000 claims description 22
- 239000004020 conductor Substances 0.000 claims description 10
- 150000002910 rare earth metals Chemical group 0.000 claims description 10
- 230000001360 synchronised effect Effects 0.000 claims description 6
- 230000002093 peripheral effect Effects 0.000 claims description 4
- 229910052761 rare earth metal Inorganic materials 0.000 claims description 4
- 238000007789 sealing Methods 0.000 claims 1
- 230000007423 decrease Effects 0.000 abstract description 4
- 239000000463 material Substances 0.000 description 17
- 239000003507 refrigerant Substances 0.000 description 17
- 239000000696 magnetic material Substances 0.000 description 14
- CNQCVBJFEGMYDW-UHFFFAOYSA-N lawrencium atom Chemical compound [Lr] CNQCVBJFEGMYDW-UHFFFAOYSA-N 0.000 description 12
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 10
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 10
- 229910052782 aluminium Inorganic materials 0.000 description 10
- 238000001816 cooling Methods 0.000 description 8
- 239000010687 lubricating oil Substances 0.000 description 8
- 229910052742 iron Inorganic materials 0.000 description 5
- 230000009471 action Effects 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 238000002955 isolation Methods 0.000 description 4
- 239000004215 Carbon black (E152) Substances 0.000 description 3
- CBENFWSGALASAD-UHFFFAOYSA-N Ozone Chemical compound [O-][O+]=O CBENFWSGALASAD-UHFFFAOYSA-N 0.000 description 3
- QJVKUMXDEUEQLH-UHFFFAOYSA-N [B].[Fe].[Nd] Chemical compound [B].[Fe].[Nd] QJVKUMXDEUEQLH-UHFFFAOYSA-N 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
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- 239000003302 ferromagnetic material Substances 0.000 description 3
- 229930195733 hydrocarbon Natural products 0.000 description 3
- 125000001183 hydrocarbyl group Chemical group 0.000 description 3
- 229910001172 neodymium magnet Inorganic materials 0.000 description 3
- 238000010792 warming Methods 0.000 description 3
- 229910000831 Steel Inorganic materials 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 239000003921 oil Substances 0.000 description 2
- 238000005057 refrigeration Methods 0.000 description 2
- 125000006850 spacer group Chemical group 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- 229910001018 Cast iron Inorganic materials 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 238000009833 condensation Methods 0.000 description 1
- 230000005494 condensation Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
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Abstract
A hermetic compressor has a bipolar permanent magnet motor where permanent magnet (124) is disposed in rotor core (123). Hollow bore (131) is disposed at the end on the compressing element (105) side of rotor core (123), and main bearing (111) extends into bore (131). The thickness of rotor core (123) is longer than that of stator core (126), thereby widening the magnetic path of rotor core (123). The magnetic flux amount generated in rotor core (123), which is conventionally insufficient due to existence of bore (131), increases, the loss decreases, and the efficiency increases.
Description
Technical Field
The present invention relates to a hermetic compressor used for a refrigeration cycle in a freezer compartment or the like of a refrigeration appliance.
Background
Recently, for a hermetic compressor used for a refrigerating apparatus in a freezer compartment of a refrigerator or the like, it is required to improve efficiency to reduce power consumption, and to reduce a size to increase a capacity efficiency of the freezer compartment of the refrigerator.
For example, japanese patent unexamined publication No.2001-73948 (hereinafter referred to as "document 1") discloses a conventional bipolar permanent magnet motor having a permanent magnet built in a rotor as a motor element instead of an induction motor to improve efficiency.
A conventional hermetic compressor will be described below with reference to the accompanying drawings.
Fig. 10 is a longitudinal sectional view of the conventional hermetic compressor in document 1. As shown in fig. 10, the hermetic container 1 accommodates a motor element 4 formed by a stator 2 and a rotor 3 and a compression element 5 driven by the motor element 4. The hermetic container 1 hermetically encloses the motor element 4 and the compression element 5.
Lubricating oil 6 is stored in sealed container 1. The shaft 10 has a main shaft 11 and an eccentric shaft 12, the rotor 3 is fixed to the main shaft 11, and the eccentric shaft 12 is formed eccentrically with respect to the main shaft 11. The cylinder block 14 has a substantially cylindrical compression chamber 15 and a main bearing 17 formed of an aluminum-based material (i.e., a non-magnetic material). A piston 19 is inserted into the compression chamber 15 of the cylinder block 14, which can slide back and forth in the compression chamber 15, and is connected to the eccentric shaft 12 through a connector 20.
The motor element 4 is a bipolar permanent magnet motor formed by:
a stator 2 in which a wire is wound on a stator core 25 made of laminated magnetic steel sheets; and
the rotor 3 in which permanent magnets 27 are built in a rotor core 26 made of laminated magnetic steel sheets.
A hollow hole 31 is arranged at an end portion of the rotor core 26 on a side facing the compression element 5, and the main bearing 17 protrudes into the hollow hole 31.
The operation of the hermetic-type compressor having this structure is described below. The rotor 3 of the motor element 4 rotates the shaft 10, and the rotation of the eccentric shaft 12 is transmitted to the piston 19 via the connector 20, thereby reciprocating the piston 19 in the compression chamber 15. By the reciprocating motion of the piston 19, the refrigerant gas is sucked from the cooling system (not shown) into the compression chamber 15, compressed, and then discharged to the cooling system again.
The flow and loss of magnetic flux in the rotation of the rotor 3 are described below. Since the main bearing 17 is made of a non-magnetic material, magnetic attraction force does not act between the inner periphery of the hole 31 and the main bearing 17, and therefore torque is not lost. Further, since the main bearing 17 is made of a non-magnetic material, the magnetic flux from the permanent magnet 27 is not attracted to the main bearing 17, and therefore most of the magnetic flux passes through only the rotor core 26. Therefore, core loss (particularly eddy current loss) hardly occurs in the main bearing 17, and thus efficiency can be improved.
However, in the conventional configuration, the magnetic circuit cannot pass through the main shaft 11 made of a non-magnetic material. The area through which the magnetic flux flows in the hole 31 of the rotor core 26 is small. Therefore, only a narrow magnetic path can be formed locally, the magnetic resistance is large, and the magnetic flux near the hole 31 is smaller than in the case where the hole 31 is not present. Therefore, the loss disadvantageously becomes very large.
When a hole is not formed in the bearing structure in order to reduce the loss in the hole 31, the main bearing 17 cannot extend into the hole 31 formed in the rotor core 26. In other words, the vertical overlap between the hole 31 and the main bearing 17 is eliminated, and therefore the rotor 3 is moved by the depth of the hole 31 to the side opposite to the compression element 5. Thereby, the height of the hermetic container 1 is disadvantageously increased by a distance equivalent to the depth of the hole 31.
Disclosure of Invention
In the hermetic compressor of the present invention, the motor element is a bipolar permanent magnet motor formed of a stator and a rotor having permanent magnets built in a rotor core. A hollow bore is arranged at the compression element side end of the rotor core, and the main bearing projects into the interior of the bore.
The axial length of the rotor core is longer than the axial length of the stator core of the stator. The magnetic path of the rotor core can be widened, so that the magnetic flux generated in the rotor core is increased, the loss is reduced, and the efficiency of the motor element is improved. This structure provides a wide magnetic path to smoothly flow the magnetic flux generated by the permanent magnet.
The spindle may be made of a magnetic material. In this case, the magnetic material main bearing and the shaft disposed inside the hole act as a magnetic circuit, so that the magnetic flux (insufficient in the conventional art) generated in the rotor increases, and the loss decreases. This structure provides a wide magnetic path to smoothly flow the magnetic flux generated by the permanent magnet.
In the hermetic-type compressor of the present invention, it is possible to form a magnetic circuit inside the hole without increasing the height of the hermetic container, and thus, the magnetic flux generated in the rotor is increased, the loss is reduced, and the efficiency is improved.
Drawings
Fig. 1 is a longitudinal sectional view of a hermetic compressor according to an exemplary embodiment 1 of the present invention.
Fig. 2 is an axial sectional view of a portion without a hole in a rotor according to exemplary embodiment 1.
FIG. 3 is an axial cross-sectional view of a portion with a hole in a rotor according to exemplary embodiment 1.
Fig. 4 is a longitudinal sectional view of a hermetic compressor according to exemplary embodiment 2 of the present invention.
Fig. 5 is a longitudinal sectional view of a hermetic compressor according to exemplary embodiment 3 of the present invention.
Fig. 6 is an enlarged sectional view of a main portion of a hermetic compressor according to exemplary embodiment 3.
FIG. 7 is an axial cross-sectional view of a portion with a hole in a rotor according to exemplary embodiment 3.
FIG. 8 is a characteristic element plot of magnetic flux density inside a bore in a rotor according to exemplary embodiment 3.
Fig. 9 is a characteristic element diagram of a coefficient of performance of a hermetic-type compressor according to exemplary embodiment 3.
Fig. 10 is a longitudinal sectional view of a conventional hermetic compressor.
Detailed Description
In the hermetic-type compressor of the present invention, the lubricating oil is reserved in the hermetic container, and the motor element and the compression element are also accommodated in the hermetic container. The compressing element has a shaft including an eccentric shaft and a main bearing for rotating the main shaft. The motor elements are bipolar permanent magnet motors formed by a stator and a rotor. The rotor has permanent magnets built in the rotor core. A hollow bore is arranged at the compression element side end of the rotor core, and the main bearing projects into the interior of the bore. The thickness (i.e., axial length) of the rotor core is longer than the axial length of the stator core of the stator. The magnetic path of the rotor core can be widened, so that the magnetic flux in the rotor core is increased, and the loss is reduced. In the conventional art, the magnetic flux is insufficient due to a narrow magnetic path caused by the hole. The thickness of the rotor core, which does not directly affect the height of the hermetic container, becomes large so that the height of the hermetic container does not increase. Therefore, the size and weight of the hermetic container can be reduced, the cost can be reduced, and the efficiency can be improved.
In the hermetic-type compressor of the present invention, both axial end portions of the rotor core may be arranged outside both axial end portions of the stator core, respectively. The magnetic centers of the stator and the rotor are substantially matched with each other so that an axial electromagnetic force is hardly generated, and the electromagnetic force acting on the rotor can be efficiently converted into a torque for rotating the shaft. Therefore, the efficiency is further improved.
In the hermetic-type compressor of the present invention, the axial length of the permanent magnet may be shorter than the axial length of the rotor core. The magnetic flux generated by the permanent magnets hardly leaks to the outside from the axial end portions of the rotor core, so that the material cost of the permanent magnets can be reduced without greatly reducing the effective magnetic flux. The cost can be further reduced.
The hermetic-type compressor of the present invention may have a configuration in which: the axial length of the permanent magnets is shorter than the axial length of the rotor core, and the permanent magnets are located on the side opposite the bore of the rotor. The magnetic flux generated by the permanent magnets is mainly generated in a wide portion of the rotor core without holes, so that a wide magnetic path can be formed, and the material cost of the permanent magnets can be reduced without greatly reducing the effective magnetic flux. The cost can be further reduced.
In the hermetic compressor of the present invention, the bipolar permanent magnet motor used as the motor element may be a self-starting permanent magnet synchronous motor having the following elements:
a plurality of conductor bars of a cage conductor for starting, located on the outer periphery of the rotor core; and
a rotor having a plurality of permanent magnets buried in an inner circumference thereof.
A synchronous motor having high efficiency may be used, and thus the efficiency of the hermetic compressor may be improved.
In the hermetic-type compressor of the present invention, the permanent magnet may be a rare earth magnet. The rare earth group magnet can provide a strong magnetic force so that the size and weight of the engine can be reduced and the size and weight of the hermetic compressor can be reduced.
In the hermetic-type compressor of the present invention, the main bearing may be made of a magnetic material. The main bearing and the shaft made of a magnetic material inside the bore serve as a magnetic circuit, so that the magnetic flux generated in the rotor increases beyond the loss caused by the eddy current generated in the main bearing, thus reducing the loss. Therefore, the efficiency of the engine element is improved and thus the efficiency of the hermetic compressor can be improved.
In the hermetic-type compressor of the present invention, the main bearing may be sintered from an iron-based material or cast from an iron-based material. The bearing may be made of an inexpensive iron-based material and may be integrally formed with the cylinder block, so that costs may be reduced.
In the hermetic-type compressor of the present invention, the depth of the hole (or the axial length of the hole) may be 1/3 or more of the thickness of the rotor core. Extending the main bearing made of magnetic material into the bore compensates for the insufficient magnetic flux in the rotor. Here, the shortage is caused by the small thickness of the portion of the rotor core having no hole. Therefore, in this case, the height of the hermetic compressor can be made smaller than the case where the rotor core has the same thickness but the holes are not arranged, and the efficiency can be improved.
In the hermetic-type compressor of the present invention, a gap between an outer peripheral edge of the hole and an inner peripheral edge of the main bearing may be set to 0.5 to 3 mm. The outer peripheral surface of the hole corresponds to the inner surface of the cylindrical hole of the rotor core. The magnetic resistance in the gap between the hole and the main bearing is reduced, a strong magnetic path is formed, leakage of magnetic flux is reduced, and magnetic flux is increased, so that efficiency can be further improved.
Exemplary embodiments of the present invention are described below with reference to the accompanying drawings. The present invention is not limited to those exemplary embodiments. The longitudinal or lateral reduction of some elements is exaggerated for clarity in the figures.
(exemplary embodiment 1)
Fig. 1 is a longitudinal sectional view of a hermetic compressor according to an exemplary embodiment 1 of the present invention. Fig. 2 is an axial sectional view of a portion of a rotor without a hole according to exemplary embodiment 1. Fig. 3 is an axial sectional view of a portion of a rotor having a hole according to exemplary embodiment 1.
In fig. 1, 2 and 3, hermetic container 101 stores lubricating oil 102 and accommodates motor element 103 and compression element 105 driven by motor element 103. Compressing element 105 has a shaft 110 including eccentric shaft 106 and main shaft 107, and a main bearing 111 for pivoting main shaft 107. The cylinder block 112 has a substantially cylindrical compression chamber 113. A main bearing 111 made of an aluminum-based material (i.e., a non-magnetic material) is fixed to the cylinder block 112. A piston 114 is inserted into the compression chamber 113 of the cylinder block 112, and the piston 114 can slide back and forth in the compression chamber 113 and is connected to the eccentric shaft 106 through a connector 115.
In exemplary embodiment 1, motor element 103 is a self-starting permanent magnet synchronous motor formed of stator 121 and rotor 125. The rotor 125 has a permanent magnet 124 built in a rotor core 123. The thickness (i.e., axial length) of the rotor core 123 is longer than the axial length of the stator core 126 of the stator 121. An end plate 127 for preventing the permanent magnets 124 from falling off is fixed to the rotor core 123. The plurality of conductive bars 128 arranged in the rotor core 123 and the short circuit rings 129 positioned at both axial ends of the rotor core 123 are integrally cast by aluminum die casting, thereby forming a cage conductor for starting.
Both axial ends of the rotor core 123 are arranged outside both axial ends of the stator core 126, respectively. In other words, the upper end of the rotor core 123 is higher than the upper end of the stator core 126, and at the same time, the lower end of the rotor core 123 is lower than the lower end of the stator core 126. A hollow hole 131 is arranged at the compression element 105-side end of the rotor core 123, and the main bearing 111 extends into the hole 131.
Here, the hole 131 is described. The rotor core 123 has a cylindrical through hole 133, and the shaft 110 is inserted into the through hole 133. The hole 131 is an annular recessed portion disposed in an upper portion of the through-hole 133. In other words, the hole 131 is a step having a diameter larger than that of the through-hole 133. Thus, the lower end of the main bearing 111 is received in the hole 131, and is thus inserted into the gap between the shaft 110 and the rotor core 123.
The permanent magnet 124 is a magnetic plate made of a neodymium iron boron ferromagnetic material (i.e., a rare earth group magnet). The permanent magnet 124 is formed of permanent magnets 124A, 124B, 124C, and 124D, which are arranged as shown in fig. 2. A pair of permanent magnets 124A and 124B of the same polarity face each other around the shaft 110 at a predetermined angle and at a predetermined interval. Meanwhile, another pair of permanent magnets 124C and 124D of the same polarity face each other around the shaft 110 at a predetermined angle and at a predetermined interval. All the permanent magnets 124A, 124B, 124C, and 124D are buried parallel to the axis of the rotor core 123. One pair of permanent magnets 124A and 124B of the same polarity forms one rotor pole, and the other pair of permanent magnets 124C and 124D of opposite polarity also forms one rotor pole. Thus, the entire rotor 125 forms two rotor poles. To prevent the magnetic flux of the adjacent permanent magnets 124A and 124C or the adjacent permanent magnets 124B and 124D from short-circuiting, an isolation 132 for preventing magnetic short-circuiting is formed. The spacers 132 are holes filled with a non-magnetic aluminum die cast material.
The refrigerant used in the compressor is a hydrocarbon refrigerant or the like, i.e., a natural refrigerant having a low global warming potential, such as R134a or R600a having a zero ozone depletion rate, and is used in combination with a lubricating oil having a high affinity.
The operation and action of the hermetic compressor having the above-described configuration are described below.
The rotor 125 of the motor element 103 rotates the shaft 110, and the rotation of the eccentric shaft 106 is transmitted to the piston 114 via the connector 115, thereby reciprocating the piston 114 in the compression chamber 113. Thereby, the refrigerant gas is sucked from the cooling system (not shown) into the compression chamber 113, and the refrigerant gas is compressed and discharged to the cooling system again.
Next, the flow of the magnetic flux of the permanent magnet 124 is conceptually described with the lines with arrows in fig. 2 and 3. The flow of magnetic flux in a portion of the rotor core 123 without the hole 131 is described in fig. 2. The magnetic flux from the permanent magnet 124A or 124B passes through the central portion of the rotor core 123 and is attracted to the permanent magnet 124C or 124D, respectively.
However, the flow of magnetic flux in the hole 131 in the rotor core 123 is described in fig. 3. The magnetic flux from the permanent magnet 124A or 124B cannot pass through the main bearing 111 made of an aluminum-based material that is a nonmagnetic material, so that the magnetic flux cannot pass into the hollow hole 131, and the magnetic flux is dispersed to the vicinity of a space formed by the outer periphery of the main bearing 111 and the inner periphery of the hole 131. Thus, the magnetic path in this portion is often liable to be narrowed and insufficient.
In exemplary embodiment 1, the axial length of the rotor core 123 is longer than the axial length of the stator core 126 of the stator 121, so that a wide magnetic path can be formed in the axial direction of the rotor core 123. As a result, the magnetic flux (insufficient in the conventional art) in the rotor core 123 increases, and the loss decreases. As described above, the motor element 103 of exemplary embodiment 1 has a wide magnetic path, and the flow of the magnetic flux of the permanent magnet 124 is smooth.
Since the axial length of the stator 123, which does not directly affect the height of the hermetic container 101, becomes long, the height of the hermetic container 101 does not increase. The height of hermetic container 101 reduces the distance of the depth (or axial length) of hole 131 as compared with the case where hole 131 is not present, and therefore hermetic container 101 can be reduced in size and weight.
Since both axial ends of the rotor core 123 are disposed outside both axial ends of the stator core 126, respectively, the magnetic centers of the stator 121 and the rotor 125 substantially match each other. Therefore, it is difficult to generate an axial electromagnetic force, and the electromagnetic force acting on the rotor 125 can be efficiently converted into torque for rotating the shaft 110, and thus efficiency is further improved.
As a result, the hermetic compressor can be reduced in size and weight, can be reduced in cost, and can be improved in efficiency.
When the hollow portion is arranged in the shaft for oil supply, the magnetic circuit is liable to become insufficient, similarly to the case with the hole 131. Therefore, the action of the above configuration further works effectively, and a similar effect can be obtained.
(exemplary embodiment 2)
Fig. 4 is a longitudinal sectional view of a hermetic compressor according to exemplary embodiment 2 of the present invention. In exemplary embodiment 2, elements similar to those in exemplary embodiment 1 are denoted by the same reference numerals, and detailed description of these elements is omitted.
In fig. 4, hermetic compressor 101 reserves lubricating oil 102 at the bottom thereof and accommodates motor element 201 and compression element 105 driven by motor element 201. Compressing element 105 has a shaft 110 including eccentric shaft 106 and main shaft 107, and a main bearing 111 for pivoting main shaft 107. The cylinder block 112 has a substantially cylindrical compression chamber 113 and a main bearing 111 made of an aluminum-based material (i.e., a non-magnetic material). A piston 114 is inserted into the compression chamber 113 of the cylinder block 112, and the piston 114 can slide back and forth in the compression chamber 113 and is connected to the eccentric shaft 106 through a connector 115.
In exemplary embodiment 2, motor element 201 is a self-starting permanent magnet synchronous motor formed of stator 202 and rotor 206. The rotor 206 has a permanent magnet 205 built therein in the rotor core 203. In exemplary embodiment 2, the thickness (i.e., axial length) of rotor core 203 is longer than the axial length of stator core 210 of stator 202. An end plate 211 for preventing the permanent magnets 205 from falling off is fixed to the rotor core 203.
A hollow hole 212 is arranged at an end portion of the rotor core 203 on the compression element 105 side, and the main bearing 111 extends into the hole 212. The axial length of the permanent magnet 205 is shorter than the axial length of the rotor core 203. The permanent magnets 205 are fixed to the lower side of the rotor core 203 without the holes 212. In other words, the permanent magnet 205 covers a region without the hole 212 in the axial direction of the rotor 206 (the height direction in fig. 4). The rotor core 203 has a cylindrical through hole 133, and the shaft 110 is inserted into the through hole 133 having the first diameter. The hole 212 is an annular recessed portion located at an upper portion of the through-hole 133. In other words, the hole 212 is a step having a second diameter larger than the first diameter of the through-hole 133. Therefore, the lower end of the main bearing 111 is received in the hole 212, and is thus inserted into the gap between the shaft 110 and the rotor core 203. The permanent magnet 205 covers a region of the rotor core 203 having the second diameter.
The permanent magnet 205 is a magnetic plate made of a neodymium iron boron ferromagnetic material (i.e., a rare earth group magnet). The permanent magnet 205 is similar in construction to fig. 2 and 3. In other words, two permanent magnets 205 form one rotor pole, and thus four permanent magnets 205 form two rotor poles in the entire rotor 206. The plurality of conductive bars arranged in the rotor core 203 and the short circuit rings 213 positioned at both axial ends of the rotor core 203 are integrally cast by aluminum die casting, thereby forming a cage conductor for starting. In order to prevent the magnetic flux of the adjacent permanent magnet 205 from being short-circuited, an isolation 132 for preventing the magnetic short-circuit is formed, and aluminum is mold-filled into a hole in the isolation 132.
The refrigerant used in the compressor is a hydrocarbon refrigerant or the like, i.e., a natural refrigerant having a low global warming potential, such as R134a or R600a having a zero ozone depletion rate, and is used in combination with a lubricating oil having a high affinity.
The operation and action of the hermetic compressor having the above-described configuration are described below.
The rotor 206 of the motor element 103 rotates the shaft 110, and the rotation of the eccentric shaft 106 is transmitted to the piston 114 via the connector 115, thereby reciprocating the piston 114 in the compression chamber 113. Thereby, the refrigerant gas is sucked from the cooling system (not shown) into the compression chamber 113, and the refrigerant gas is compressed and discharged to the cooling system again.
Next, the magnetic flux flow of the permanent magnet 205 is conceptually described. The flux flow in the portion of rotor 206 without holes 212 is similar to that in fig. 2. The magnetic flux from the permanent magnet 205 passes through the central portion of the rotor core 203. Meanwhile, the magnetic flux flow in the portion of the rotor core 206 having the hole 212 is similar to that in fig. 3. The magnetic flux from the permanent magnet 205 cannot pass through the hollow hole 212 because the main bearing 111 made of a non-magnetic material exists in the hole 212. Thereby the magnetic flux is dispersed to the vicinity of the space formed by the outer periphery of the main bearing 111 and the inner periphery of the hole 212. Thereby, the magnetic path in this portion is liable to be narrowed and is insufficient.
However, since the axial length of the permanent magnet 205 is shorter than that of the rotor core, the magnetic flux generated by the permanent magnet 205 hardly leaks to the outside from the axial end of the rotor core 203. Thus, the material cost of the permanent magnet 205 may be reduced without substantially reducing the effective magnetic flux. As described above, the motor element 103 of exemplary embodiment 2 has a wide magnetic path, and the flow of the magnetic flux generated by the permanent magnet 205 is smooth.
The permanent magnet 205 is arranged in the vertical direction of the rotor 206 at a lower position opposite to the upper position having the hole 212. Minimizing vertical overlap between the permanent magnet 205 and the hole 212. In this configuration, the magnetic flux generated by the permanent magnet 205 exists in a large part of the rotor core 203 where the hole 212 is absent, so that a magnetic path wider than the size of the permanent magnet 205 can be formed, and the material cost of the permanent magnet 205 can be reduced without greatly reducing the effective magnetic flux of the permanent magnet 205. Thus, efficiency is improved and costs are reduced at the same time.
The permanent magnet 205 is a rare earth magnet. The rare earth group magnet can exert a strong magnetic force, so that the motor can be reduced in size and weight, and the hermetic compressor can be reduced in size and weight.
Therefore, the size and weight can be further reduced, the cost can be reduced, and the efficiency can be improved.
When a hollow hole such as a passage for oil supply is disposed in the main shaft 107 of the shaft 110, the magnetic circuit tends to become insufficient similarly to the case with the hole 212. Therefore, the operation by the above configuration can further effectively work, and a similar effect can be obtained.
(exemplary embodiment 3)
Fig. 5 is a longitudinal sectional view of a hermetic compressor according to exemplary embodiment 3 of the present invention. Fig. 6 is an enlarged sectional view of a main portion of a hermetic compressor according to exemplary embodiment 3. Fig. 7 is an axial sectional view of a portion having a hole in a rotor according to exemplary embodiment 3. Fig. 8 is a characteristic element diagram between the magnetic flux density inside the hole and the clearance between the diameter of the hole and the outer diameter of the main bearing in the rotor according to example embodiment 3. Fig. 9 is a comparative characteristic diagram of coefficient of performance c.o.p of the hermetic compressor. In exemplary embodiment 3, those elements that are similar to those of exemplary embodiment 1 are denoted by the same reference numerals, and the description of those elements is simplified.
As shown in fig. 5, 6 and 7, hermetic container 101 stores lubricating oil 102 inside, and accommodates motor element 103 and compression element 105. Compressing element 105 has a shaft 110 including eccentric shaft 106 and main shaft 107, and a main bearing 111 that pivots main shaft 107. The cylinder block 112 has a substantially cylindrical compression chamber 113 and a main bearing 111 made of a cast iron-based material (i.e., a magnetic material). The piston 114 is inserted into the compression chamber 113 of the cylinder block 112 to slide back and forth, and is connected to the eccentric shaft 106 through a connector 115.
The motor element 103 is a self-starting permanent magnet synchronous motor formed of a stator 121 and a rotor 306. The rotor 306 has a permanent magnet 305 built in the rotor core 303. An end plate 311 for preventing the permanent magnets 305 from falling off is fixed to the rotor core 303. The plurality of conductive bars 308 arranged in the rotor core 303 and the short-circuit rings 309 positioned at both axial ends (in other words, upper and lower ends) of the rotor core 303 are integrally cast by aluminum die casting, thereby forming a cage conductor for starting.
A hollow hole 131 is arranged at an end portion on the compression element 105 side of the rotor core 303, and the main bearing 111 extends into the hole 131.
As shown in fig. 6, the thickness of the rotor core 303 is denoted by L, the inner diameter and depth of the hole 131 are denoted by D1 and M, respectively, and the outer diameter of the main bearing 111 is denoted by D2. In exemplary embodiment 3, the depth M is set to 1/3 or more of the thickness L, and the gap G between the outer periphery of the main bearing 111 and the inner periphery of the hole 131 is set to 0.5 to 3 mm. Here, G ═ (D1-D2)/2.
The permanent magnet 305 is a magnetic plate made of a neodymium iron boron ferromagnetic material (i.e., a rare earth group magnet). The permanent magnet 305 is formed of permanent magnets 305A, 305B, 305C, and 305D, and they are arranged as shown in fig. 7. A pair of permanent magnets 305A and 305B of the same polarity face each other around the shaft 110 at a predetermined angle and at a predetermined interval. Meanwhile, another pair of permanent magnets 305C and 305D of the same polarity face each other around the shaft 110 at a predetermined angle and at a predetermined interval. All the permanent magnets 305A, 305B, 305C, and 305D are buried parallel to the axis of the rotor core 303. One pair of permanent magnets 305A and 305B of the same polarity forms one rotor pole and the other pair of permanent magnets 305C and 305D of the opposite polarity also forms one rotor pole. Thus, the entire rotor 306 forms two rotor poles. In order to prevent the magnetic flux of the adjacent permanent magnets 305A and 305C or the adjacent permanent magnets 305B and 305D from being short-circuited, the isolation 132 for preventing the magnetic short-circuit is formed. The spacers 132 are holes in which the filling is made by aluminum molding.
The refrigerant used in the compressor is a hydrocarbon refrigerant or the like, i.e., a natural refrigerant having a low global warming potential, such as R134a or R600a having a zero ozone depletion rate, and is used in combination with a lubricating oil having a high affinity.
The operation and action of the hermetic compressor having the above-described configuration are described below.
The flux flow of the permanent magnet 305 is conceptually described by the line with an arrow in fig. 7. Fig. 7 shows the flow of magnetic flux in the hole 131 in the rotor core 303. As shown in fig. 7, the magnetic flux from the permanent magnet 305A or 305B passes through the gap between the outer periphery of the main bearing 111 and the inner periphery of the hole 131, the main bearing 111, and the shaft 110, and is attracted into the permanent magnet 305C or 305D, respectively.
At this time, the main bearing 111 extending into the hole 131 does not rotate, so that the propagation of the magnetic flux causes eddy current loss. However, the torque lost due to the eddy current induced on the outer diameter of the main bearing 111 is relatively smaller than the torque generated on the outer periphery of the rotor 303 by the motor itself. This is because the distance to the rotating shaft is short and therefore the force as a braking torque is small. Meanwhile, the main bearing 111 and the shaft 110 made of a magnetic material form a magnetic circuit, so that a magnetic flux generated in the rotor 306 increases. This effect increases with increasing depth M of the hole 131. As a result, the influence of the torque loss is relatively small. Therefore, the increase of the magnetic flux generated in the rotor 306 reduces the loss to improve the efficiency of the motor element 103, and thus the efficiency of the hermetic compressor can be improved. As described above, the motor element 103 of exemplary embodiment 3 has a wide magnetic path, and the flow of the magnetic flux generated by the permanent magnet 305 is smooth.
Since the depth of the hole 131 is set to 1/3 or more, which is very deep, of the thickness L in exemplary embodiment 3, especially the magnetic flux generated in the rotor 306 increases, the efficiency improvement effect is significant, and the entire height of the compressor is kept very low.
The main bearing 111 may be made of an inexpensive cast or sintered material, and may be integrally formed with the cylinder block 112, so that costs may be reduced.
As shown in fig. 8, when the gap G between the hole 131 and the main bearing 111 (where G ═ D1-D2)/2) increases, the magnetic flux density inside the hole 131 decreases. However, when the gap G is increased to be larger than 3mm, the magnetic flux density is hardly decreased. A clearance of up to 3mm is considered suitable when the main bearing 111 and the shaft 110 serve as a magnetic path through which magnetic flux passes. However, in view of the machining accuracy of the outer periphery of the main bearing 111 and the inner periphery of the hole 131, a gap G of 0.5 to 3mm is most preferable and effective. Therefore, by applying the above conditions, the magnetic resistance is reduced, a strong magnetic path is formed, leakage of magnetic flux is reduced, magnetic flux is increased, and efficiency is further improved.
In starting, a large current flows in the conductor bar 308 to generate a torque. The magnetic force generated by the built-in permanent magnet 305 acts as a braking torque during starting, and thus a large starting torque is required. In exemplary embodiment 3, the conductor bar 308 can be lengthened, the starting torque can be increased, so that the starting performance is good and high efficiency can be obtained.
More preferably, the permanent magnet 305 is formed of a rare earth magnet. The rare earth group magnet can exert a strong magnetic force, so that the motor can be reduced in size and weight, and the hermetic compressor can be reduced in size and weight.
Therefore, the size and weight can be further reduced, the cost can be reduced, and the efficiency can be improved.
In exemplary embodiment 3, a main bearing 111 cast from an iron-based material is integrally formed in a cylinder block 112. The construction of mounting the main bearing 111 made of an iron-based sintered material also produces similar advantages.
The improvement of the efficiency of the hermetic-type compressor in exemplary embodiment 3 is described below.
In fig. 9, the vertical axis shows the characteristics of coefficient of performance c.o.p (W/W) of the hermetic-type compressor of the conventional art and the hermetic-type compressor of exemplary embodiment 3. Here, R600a is used as the refrigerant, and the operating frequency of the reciprocating motion of the piston is 50 Hz. The working temperature conditions were close to those in the refrigerator, the evaporation temperature was-25 deg.c, and the condensation temperature was 55 deg.c.
As is apparent from the results of fig. 9, in the hermetic-type compressor of exemplary embodiment 3, the c.o.p. is greatly improved and the efficiency is improved as compared with the conventional hermetic-type compressor.
Industrial applicability
In the hermetic-type compressor of the present invention, the magnetic flux in the rotor core is increased to reduce the loss, the size and weight can be reduced, and the efficiency can be improved. Therefore, the hermetic compressor can be applied to a refrigerator of an air conditioner or a refrigerator.
Claims (6)
1. A hermetic compressor comprising:
sealing the container;
a motor element accommodated in the hermetic container; and
a compression element accommodated in the hermetic container and driven by the motor element,
wherein,
the compressing element has a shaft including an eccentric shaft and a main bearing for supporting the main shaft to be rotatable,
the motor element is a bipolar permanent magnet motor having a stator and a rotor, the rotor having permanent magnets built-in a rotor core,
a hollow hole is formed on the compression element side end portion of the rotor core, and
the axial length of the rotor core is longer than that of the stator core of the stator, and the axial length of the permanent magnet is shorter than that of the rotor core, thereby providing a wide magnetic path to smoothly flow the magnetic flux generated by the permanent magnet.
2. The hermetic compressor of claim 1, wherein both axial ends of the rotor core are disposed outside both axial ends of the stator core, respectively.
3. The hermetic-type compressor of claim 1,
the permanent magnets cover a region having no hollow hole in an axial direction of the rotor.
4. The hermetic-type compressor of claim 1,
the rotor core has a cylindrical through hole having a first diameter, the shaft is inserted into the through hole,
the hollow hole is a cylindrical concave portion formed in an upper portion of the through hole and has a second diameter larger than the first diameter,
the permanent magnet covers a region of the rotor having the first diameter in an axial direction of the rotor core.
5. The hermetic-type compressor of claim 1,
the motor element is a self-starting permanent magnet synchronous motor,
the motor element has a plurality of conductor bars of a cage conductor for starting on the outer periphery of the rotor core, and
the permanent magnet is arranged on an inner peripheral side of the conductor bar.
6. The hermetic compressor of claim 1, wherein the permanent magnet is a rare earth magnet.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP338443/2004 | 2004-11-24 | ||
| JP2004338443 | 2004-11-24 | ||
| JP340235/2004 | 2004-11-25 |
Related Child Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2008101112526A Division CN101354026B (en) | 2004-11-24 | 2005-11-22 | hermetic compressor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1842653A CN1842653A (en) | 2006-10-04 |
| CN100427757C true CN100427757C (en) | 2008-10-22 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB2005800009645A Expired - Fee Related CN100427757C (en) | 2004-11-24 | 2005-11-22 | Hermetic compressor |
| CN2008101112526A Expired - Fee Related CN101354026B (en) | 2004-11-24 | 2005-11-22 | hermetic compressor |
Family Applications After (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2008101112526A Expired - Fee Related CN101354026B (en) | 2004-11-24 | 2005-11-22 | hermetic compressor |
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| Country | Link |
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| CN (2) | CN100427757C (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102444580B (en) * | 2010-09-30 | 2016-03-23 | 艾默生电气公司 | With the digital compressor of across-the-line starting brushless permanent magnet electromotor |
| DE102010051262A1 (en) * | 2010-11-12 | 2012-05-31 | Secop Gmbh | Refrigeration compressor i.e. hermetically-sealed refrigeration compressor, for use in e.g. freezer, has stator provided with bundle of laminations, where axial center of bundle of laminations is located higher than axial center of magnets |
| CN106385117A (en) * | 2016-11-29 | 2017-02-08 | 安徽美芝制冷设备有限公司 | Motor used for compressor and compressor |
| CN108306466A (en) * | 2018-01-22 | 2018-07-20 | 安徽美芝制冷设备有限公司 | The manufacturing method of motor |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH08247030A (en) * | 1995-03-14 | 1996-09-24 | Matsushita Refrig Co Ltd | Electric compressor |
| JPH08270558A (en) * | 1995-03-31 | 1996-10-15 | Matsushita Refrig Co Ltd | Compressor |
| JPH10318132A (en) * | 1997-05-22 | 1998-12-02 | Matsushita Refrig Co Ltd | Erectrically driven compressor |
| JP2001073948A (en) * | 1999-07-02 | 2001-03-21 | Matsushita Refrig Co Ltd | Electric compressor |
| CN1316037A (en) * | 1999-07-02 | 2001-10-03 | 松下电器产业株式会社 | Electric compressor |
| JP2003074472A (en) * | 2001-08-31 | 2003-03-12 | Toshiba Kyaria Kk | Electric compressor |
| CN1521397A (en) * | 2003-02-12 | 2004-08-18 | 松下电器产业株式会社 | electric compressor |
-
2005
- 2005-11-22 CN CNB2005800009645A patent/CN100427757C/en not_active Expired - Fee Related
- 2005-11-22 CN CN2008101112526A patent/CN101354026B/en not_active Expired - Fee Related
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH08247030A (en) * | 1995-03-14 | 1996-09-24 | Matsushita Refrig Co Ltd | Electric compressor |
| JPH08270558A (en) * | 1995-03-31 | 1996-10-15 | Matsushita Refrig Co Ltd | Compressor |
| JPH10318132A (en) * | 1997-05-22 | 1998-12-02 | Matsushita Refrig Co Ltd | Erectrically driven compressor |
| JP2001073948A (en) * | 1999-07-02 | 2001-03-21 | Matsushita Refrig Co Ltd | Electric compressor |
| CN1316037A (en) * | 1999-07-02 | 2001-10-03 | 松下电器产业株式会社 | Electric compressor |
| JP2003074472A (en) * | 2001-08-31 | 2003-03-12 | Toshiba Kyaria Kk | Electric compressor |
| CN1521397A (en) * | 2003-02-12 | 2004-08-18 | 松下电器产业株式会社 | electric compressor |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1842653A (en) | 2006-10-04 |
| CN101354026B (en) | 2010-07-21 |
| CN101354026A (en) | 2009-01-28 |
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