JP4823787B2 - Rotor, hermetic compressor and refrigeration cycle apparatus - Google Patents

Description

  The present invention relates to a rotor using a permanent magnet, a hermetic compressor, and a refrigeration cycle apparatus.

  In a high-efficiency hermetic compressor used in a refrigeration cycle, a brushless DC motor having a permanent magnet disposed on a rotor is used as an electric element, and a method of operating at a variable frequency by a dedicated control device having an inverter is used.

  Usually, a rotor in which permanent magnets are arranged generally has a structure in which a magnet insertion hole is provided in a rotor core obtained by punching and laminating thin electromagnetic steel sheets, and the permanent magnet is fitted into the rotor core with a gap.

  Further, the rotor has a shaft hole into which the rotating shaft is fitted, and the fitting between the rotor and the rotating shaft is performed by heating the rotor and expanding the diameter of the shaft hole so that the rotating shaft is fitted into the shaft hole. The shrink-fitting is generally inserted into

  However, in the rotor in which the permanent magnet is arranged, the performance of the permanent magnet may be deteriorated when the temperature of the permanent magnet is increased during shrink fitting.

Therefore, for example, in order to prevent damage caused by melting or deterioration of the plastic constituting the bonded magnet even if the rotary shaft is shrink-fitted in a state where the Bond (registered trademark) magnet is previously formed on the outer periphery of the iron core. The rotor of the electric motor includes a columnar iron core having a shaft hole into which a rotating shaft is fitted, and a cylindrical plastic bond magnet integrally formed on the outer periphery of the iron core. The iron core has a structure in which the inner layer portion on the shaft hole side and the outer layer portion on the bond magnet side are connected by a plurality of bridging portions arranged at intervals in the circumferential direction. When the iron core is heated from the shaft hole side in order to shrink fit the rotating shaft, the cross-sectional area of the iron core increases the thermal resistance due to the reduced cross-sectional area. Therefore, a rotor of an electric motor that suppresses the temperature rise of the bonded magnet has been proposed (see, for example, Patent Document 1).
JP 2000-92762 A

  However, when a rare earth magnet or the like is used for the permanent magnet, it is not sufficient to reduce the heat transfer from the inner layer portion to the outer layer portion of the iron core by the bridging portion as in Patent Document 1, and the performance of the permanent magnet is deteriorated. There is a case.

  The present invention has been made to solve the above-described problems. In a rotor in which a permanent magnet is arranged, the performance of the permanent magnet is deteriorated even if the rotating shaft is fitted to the rotor by shrink fitting. An object of the present invention is to provide a rotor, a hermetic compressor, and a refrigeration cycle apparatus with less fear.

  A rotor according to the present invention is obtained by punching and laminating thin electromagnetic steel sheets, having a shaft hole in the center, a substantially cylindrical rotor core, and a rotor core provided in the rotor core, wherein the shaft hole is formed inside. 1 pipe part, the 2nd pipe part which is arranged on the outside of the first pipe part and has a plurality of magnet insertion holes formed in the circumferential direction, the first pipe part, and the second pipe part are connected, A rib portion disposed at intervals in the circumferential direction; and a hole formed radially outside the rib portion and formed in the axial direction. The first tube portion and the second tube portion are separated from each other. It is arranged and formed so as to have a hollow portion surrounded by the first tube portion, the second tube portion and the rib portion, and is formed in the axial direction between the hole formed in the axial direction and the hollow portion. The thin-walled portion has a predetermined thickness.

  With the above configuration, the rotor according to the present invention is less likely to deteriorate the performance of the permanent magnet even when the rotary shaft is fitted to the rotor by shrink fitting.

Embodiment 1 FIG.
1 to 5 show the first embodiment. FIG. 1 is a sectional view of a hermetic compressor 37. FIG. 2 is a sectional view of a rotor core 21 before a permanent magnet is inserted. FIG. 4 is a cross-sectional view of the rotor 11 in which the permanent magnet 24 is inserted into the iron core 21, and FIG. 4 is a result of analyzing the temperature of the inner wall portion of the magnet insertion hole 22 when the first pipe portion 56 of the rotor 11 is heated with respect to the four types of rotor 11. FIG. 5 is a diagram showing a modified example of the rotor core 21.

  The overall configuration of the hermetic compressor 37 will be described with reference to FIG. The hermetic compressor 37 will be described by taking a one-cylinder rotary compressor as an example. The hermetic compressor 37 accommodates a compression element 2 that compresses a refrigerant and an electric element 3 that drives the compression element 2 in a hermetic container 1 composed of an upper container 1a and a lower container 1b. . The compression element 2 and the electric element 3 are connected by a crankshaft 4, and the compression element 2 is accommodated in the lower part of the sealed container 1 and the electric element 3 is accommodated in the upper part of the sealed container 1.

  In the compression element 2, a rolling piston 9 that fits in the eccentric portion 8 of the crankshaft 4 is housed in a cylinder 5, and one end of a vane (not shown) that reciprocates radially in a groove provided in the cylinder 5 is a rolling piston. A compression chamber is formed in contact with the outer periphery of 9. Openings at both axial ends of the cylinder 5 are closed by a main bearing 6 and a sub-bearing 7.

  Next, the electric element 3 will be described with reference to FIGS. 2 to 3 in addition to FIG. The electric element 3 includes a stator 10 and a rotor 11 and is, for example, a brushless DC motor. The stator 10 is divided in two in the axial direction into a stator core formed by stacking stator core sheets formed by punching thin electromagnetic steel sheets and a plurality of teeth formed on the inner diameter side of the stator core. Insulating member 15 fitted together, copper wire 16 having an insulating film wound on insulating member 15, and copper wires 16 or copper wire 16 and lead wire 17 are connected on insulating member 15 Terminal.

  The rotor 11 is configured by laminating a rotor core sheet formed by punching a thin electromagnetic steel plate, and adjacent to the magnet insertion hole 22 and the magnet insertion hole 22, a plurality of air holes 40 formed on the center side in the radial direction. (6 in the example of FIG. 2), air holes 45 formed between the air holes 40 (one example of holes formed in the axial direction, three in the example of FIG. 2) and rivet holes 46 (formed in the axial direction) 2 in the example of FIG. 2, and the slit core 47 formed on the radial center side of the air hole 40 (an example of the cavity, 6 in the example of FIG. 2). And a permanent weight 24 inserted into the magnet insertion hole 22 and an end balance weight 25a (sealed compression) which is disposed at both ends of the rotor core 21 and also serves as an end plate for preventing the permanent magnet 24 from scattering. In the machine 37, it is arranged at the upper end of the rotor core 21) and (In the hermetic compressor 37 is disposed at the lower end portion of the rotor core 21) under the balance weight 25b includes a upper balance weight 25a, and a rivet 26 securing the lower balance weight 25b, and the rotor core 21. The rivet 26 is inserted into the rivet hole 46. The upper balance weight 25a, the lower balance weight 25b, and the end plate may be separate parts.

  As shown in FIG. 2, the substantially cylindrical rotor core 21 has a plurality of magnet insertion holes 22 (six in FIG. 2) extending in the circumferential direction on the inner side of the outer peripheral surface for the number of poles. The air holes 40 are formed adjacent to each other in the radial center of each magnet insertion hole 22 (six in FIG. 2). For example, at least one circular air hole 40 is provided for the magnet insertion hole 22. The original role of the air hole 40 is to guide the refrigerant gas discharged from the compression element 2 to the upper part of the sealed container 1 and to drop the refrigerating machine oil guided to the upper part of the sealed container 1 together with the refrigerant gas to the lower part of the sealed container 1. It is. A thin portion is formed between the air hole 40 and each magnet insertion hole 22, and the thin portion is deformed to fix the permanent magnet 24.

  Another air hole 45 is provided between the air holes 40. A rivet hole 46 for inserting the rivet 26 for fixing the upper balance weight 25a, the lower balance weight 25b and the rotor core 21 between the adjacent air holes 40 in the circumferential direction of the air holes 40 provided with the air holes 45 is provided. Provided. The air holes 45 and the rivet holes 46 are alternately arranged in the circumferential direction.

  A plurality of slit portions 47 (an example of a hollow portion) are formed at intervals in the circumferential direction on the outer side of the shaft hole 49 in which the crankshaft 4 is fitted in the rotor core 21. A portion between the slit portions 47 is referred to as a rib portion 55.

  A substantially cylindrical portion having the inner side of the slit portion 47 as the outer peripheral surface and the shaft hole 49 as the inner peripheral surface is referred to as a first tube portion 56.

  A substantially cylindrical portion having the outer side of the slit portion 47 as the inner peripheral surface and the outer peripheral surface of the rotor core 21 as the outer peripheral surface is referred to as a second pipe portion 57.

  The first pipe part 56 and the second pipe part 57 are connected by a rib part 55.

  An air hole 45 and a rivet hole 46 are formed close to the outside of the rib portion 55. A thin portion 48 a is provided between the air hole 45 and the slit portion 47, and a thin portion 48 b is provided between the rivet hole 46 and the slit portion 47. The air holes 45 and the rivet holes 46 are circular in FIG. 2, but may be other shapes such as long holes and polygons.

  FIG. 3 shows the rotor 11 in which the permanent magnet 24 is inserted into the magnet insertion hole 22 of the rotor core 21.

  When the crankshaft 4 is shrink-fitted into the shaft hole 49, the first tube portion 56 is heated from the inside of the first tube portion 56, that is, from the shaft hole 49 (for example, high-frequency heating by a coil) to expand the shaft hole 49. . At this time, due to the presence of the slit portion 47, the air hole 45, and the rivet hole 46, heat transfer to the permanent magnet 24 existing in the second tube portion 57 is suppressed.

  The results of confirming the effect of suppressing heat transfer to the permanent magnet 24 when the first pipe portion 56 is heated by the slit portion 47, the air hole 45, and the rivet hole 46 are shown below.

FIG. 4 shows the result of analyzing the inner wall temperature of the magnet insertion hole 22 when the first pipe portion 56 of the rotor 11 is heated (heated from the inner peripheral side of the first pipe portion 56) for the following four types of rotors 11. It is. The temperature of the inner wall portion of the magnet insertion hole 22 when the temperature of the inner peripheral portion of the first pipe portion 56 reaches a predetermined temperature that can be shrink-fitted at the time of shrink fitting of the crankshaft 4 was obtained.
(1) No slit 47 (in FIG. 2, there is no slit 47 and only the air hole 45 and the rivet hole 46).
(2) The slit portion 47, the air hole 45, and the rivet hole 46 are provided, and the thickness of the thin portion 48a is 0.81 mm (the thickness of the thin portion 48b is the same).
(3) The slit portion 47, the air hole 45, and the rivet hole 46 are provided, and the thickness of the thin portion 48a is 0.64 mm (the thickness of the thin portion 48b is the same).
(4) The slit portion 47, the air hole 45, and the rivet hole 46 are provided, and the thickness of the thin portion 48a is 0.55 mm (the thickness of the thin portion 48b is the same).

  When the inner peripheral surface of the first pipe portion 56 of the rotor 11 is heated at a high frequency under a predetermined heat input condition using a coil, for example, the temperature of the inner peripheral surface of the first pipe portion 56 is about a few seconds in about 10 seconds. Since it reaches 100 ° C., the heating is finished here. At this time, the temperature of the inner wall portion of the magnet insertion hole 22 is still low and 50 ° C. or less. After the end of heating, the temperature of the inner peripheral surface of the first pipe portion 56 decreases for a while and becomes close to a predetermined temperature at which shrink fitting can be performed in about 20 seconds from the start of heating. On the other hand, the temperature of the inner wall portion of the magnet insertion hole 22 gradually increases from the start of heating, and the time when the temperature of the inner peripheral surface of the first tube portion 56 reaches the shrink-fit temperature (about 20 seconds from the start of heating) Saturates almost.

  As shown in FIG. 4, the magnet without the slit portion 47 of (1) is a magnet when the temperature of the inner peripheral portion of the first pipe portion 56 becomes a predetermined temperature that can be shrink-fitted when the crankshaft 4 is shrink-fitted. The inner wall temperature of the insertion hole 22 is about 177 ° C.

  On the other hand, the slit portion 47, the air hole 45, and the rivet hole 46 of (2), and the thin portion 48a having a thickness of 0.81 mm, are included in the first pipe portion 56 when the crankshaft 4 is shrink-fitted. The inner wall temperature of the magnet insertion hole 22 when the temperature of the peripheral portion reaches a predetermined temperature at which shrink fitting can be performed is about 100 ° C.

  Further, (3) the slit portion 47, the air hole 45, and the rivet hole 46, and the thin portion 48a having a thickness of 0.64 mm is the inner peripheral portion of the first pipe portion 56 when the crankshaft 4 is shrink-fitted. The temperature of the inner wall of the magnet insertion hole 22 when the temperature becomes a predetermined temperature at which shrink fitting can be performed is about 89 ° C.

  Further, (4) the slit portion 47, the air hole 45, and the rivet hole 46, and the thin portion 48a having a thickness of 0.55 mm, is the inner peripheral portion of the first pipe portion 56 when the crankshaft 4 is shrink-fitted. The temperature of the inner wall of the magnet insertion hole 22 when the temperature becomes a predetermined temperature at which shrink fitting can be performed is about 82 ° C.

  As described above, the slit portion 47, the air hole 45, and the rivet hole 46 are provided, and the thickness of the thin portion 48a between the slit portion 47 and the air hole 45 and the thickness of the thin portion 48b between the slit portion 47 and the rivet hole 46 are set. For example, when the crankshaft 4 is shrink-fitted by setting it to 0.81 mm or less, even if the inner peripheral portion of the first pipe portion 56 is heated to a temperature higher than a predetermined shrinkable temperature that is a shrink-fitting temperature, the heat is magnetized. As shown in FIG. 4, the temperature is not higher than about 100 ° C., and even if the permanent magnet 24 is inserted into the magnet insertion hole 22, there is little risk of lowering the performance. By using this rotor 11 for the electric element 3 of the hermetic compressor 37, stable performance can be obtained.

  FIG. 5 shows a modification of the rotor core 21. In the example of FIG. 5, the slit portion 61 a has a shape having an air hole portion at substantially the center. Further, the slit portion 61b adjacent to the slit portion 61a via the rib portion 55 has a shape having a rivet hole portion at substantially the center. The slit portions 61a and the slit portions 61b are alternately arranged in the circumferential direction. In the case of FIG. 5, three slit portions 61a and three slit portions 61b are formed. However, this is an example, and any number may be used. And the air hole 60 (an example of the hole formed in the axial direction) is arrange | positioned in the radial direction outer side of the rib part 55 formed between the slit part 61a and the slit part 61b. There is a thin portion 62 a between the slit portion 61 a and the air hole 60, and there is a thin portion 62 b between the slit portion 61 b and the air hole 60. The thickness of the thin portion 62a and the thin portion 62b is preferably set to 0.81 mm or less, for example. The present embodiment is particularly effective because the demagnetization of the permanent magnet 24 can be suppressed when the crankshaft 4 is shrink-fitted into the shaft hole 49 after the permanent magnet 24 is magnetized.

Embodiment 2. FIG.
FIG. 6 is a diagram showing the second embodiment and is a refrigerant circuit diagram of the air conditioner. As shown in FIG. 6, the refrigerant circuit of the air conditioner includes a hermetic compressor 37, a four-way valve 50, an outdoor heat exchanger 51, a decompression device 52 (electronic expansion valve), an indoor heat exchanger 53, and an accumulator for the refrigerant circuit. 54.

  During the cooling operation, as shown by the solid line in FIG. 6, the refrigerant includes the hermetic compressor 37, the four-way valve 50, the outdoor heat exchanger 51, the decompression device 52, the indoor heat exchanger 53, the four-way valve 50, and the refrigerant circuit. It flows in the order of the accumulator 54 and the hermetic compressor 37.

  During the heating operation, as shown by the broken line in FIG. 6, the refrigerant includes the hermetic compressor 37, the four-way valve 50, the indoor heat exchanger 53, the decompression device 52, the outdoor heat exchanger 51, the four-way valve 50, and the refrigerant circuit. It flows in the order of the accumulator 54 and the hermetic compressor 37.

  By using the hermetic compressor 37 of the first embodiment, an air conditioner with stable performance can be obtained.

  Although the air conditioner has been described as an example, the hermetic compressor 37 can be used for a device that uses a refrigeration cycle, for example, a refrigeration cycle device such as a refrigerator, a showcase, or a water heater.

FIG. 5 shows the first embodiment, and is a cross-sectional view of a hermetic compressor 37. FIG. It is a figure which shows Embodiment 1, and is sectional drawing of the rotor core 21 before inserting a permanent magnet. FIG. 3 shows the first embodiment, and is a cross-sectional view of the rotor 11 in which a permanent magnet 24 is inserted into the rotor core 21. FIG. 5 shows the first embodiment, and shows the results of analyzing the inner wall portion temperature of the magnet insertion hole 22 when the first pipe portion 56 of the rotor 11 is heated with respect to four types of rotors 11. FIG. 5 shows the first embodiment, and shows a modification of the rotor core 21. FIG. It is a figure which shows Embodiment 2, and is a refrigerant circuit figure of an air conditioner.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Airtight container, 1a Upper container, 1b Lower container, 2 Compression element, 3 Electric element, 4 Crankshaft, 4a Main shaft, 4b Secondary shaft, 5 Cylinder, 6 Main bearing, 7 Secondary bearing, 8 Eccentric part, 9 Rolling piston, 10 Stator, 11 Rotor, 13 Stator core, 13a Teeth, 15 Insulating member, 16 Copper wire, 17 Lead wire, 19 Glass terminal, 21 Rotor core, 22 Magnet insertion hole, 24 Permanent magnet, 25a Balance on top Weight, 25b Lower balance weight, 26 rivets, 27 Accumulator, 28 Suction connection pipe, 29 Discharge pipe, 37 Sealed compressor, 40 Air hole, 40a Protruding part, 45 Air hole, 46 Rivet hole, 47 Slit part, 48a Thin wall part, 48b Thin portion, 49 shaft hole, 50 four-way valve, 51 outdoor heat exchanger, 52 decompression device, 53 indoor Exchanger, 54 refrigerant circuit accumulator 55 rib portion, the first tubular portion 56, 57 the second tubular portion, 60 air holes, 61a slits, 61b slits, 62a thin portion, 62b thin portion.

Claims (3)

In a rotor used for an electric element of a hermetic compressor that operates using refrigerant gas and refrigeration oil,
Thin electromagnetic steel plates are punched laminated, and the rotor core having a substantially cylindrical shape that have the axial hole in the center,
A first pipe part provided on the rotor core and forming the shaft hole inside;
A second tubular portion disposed on the outer side of the first pipe section, and the magnet insertion holes formed in plural in a circumferential direction, the plurality of magnet insertion holes to guide and the refrigerant gas and the refrigerating machine oil A plurality of air holes that are formed on the center side in the radial direction and formed with thin portions between the magnet insertion holes, and a plurality of permanent magnets that are deformed and fixed to the magnet insertion holes by deforming the thin portions . A pipe section;
A rib portion that connects the first tube portion and the second tube portion and is disposed at intervals in the circumferential direction;
It is formed on the outer side in the radial direction of the rib portion, and has a hole formed in the axial direction.
The first pipe part and the second pipe part are arranged so as to be spaced apart from each other and have a hollow part surrounded by the first pipe part, the second pipe part, and the rib part, and the shaft A rotor having a thin wall portion of 0.81 mm or less formed in an axial direction between a hole formed in a direction and the hollow portion. In a sealed container, a motor element comprising a stator and a rotating rotor, in the hermetic compressor that houses a compression element driven by the electric element,
A hermetic compressor using the rotor according to claim 1 as the rotor of the electric element.   A refrigeration cycle apparatus using the hermetic compressor according to claim 2.