1. Field
The field relates to a compressor, and more particularly, to a rotary compressor and an air conditioner having the same.
2. Background
In general, a compressor converts mechanical energy into compressive energy. Compressors may typically be categorized into a reciprocating type, a scroll type, a centrifugal type, a rotary type and a vane type. A rotary compressor may be used to, for example, drive a refrigerating cycle such as, for example, in an air conditioner. A rotary compressor may include a driving motor which drives a compression part to compress fluid. The driving motor may be, for example, an induction motor, which has a simple structure, low cost, and is easily handled. However, slippage between the stator and the rotor of a motor can degrade performance in an induction motor. Further, induction current flow into the rotor generates heat, which lowers efficiency due to thermal loss.
Descriptions of rotary compressors and operation thereof can be found, for example, in U.S. Pat. Nos. 6,336,800, 6,312,233, and 6,250,899, which are subject to an obligation of assignment to the same entity, and the entirety of which is incorporated herein by reference.
The embodiments will be described in detail with reference to the following drawings in which like reference numerals refer to like elements wherein:
A rotary compressor and components thereof in accordance with embodiments as broadly described herein are shown in
Some rotary compressors have used a chlorofluorocarbon (CFC)-based refrigerant such as for example, CFC 11, CFC 12, CFC 113, CFC 114, and CFC 115. However, the use of these CFC-based refrigerants has been restricted worldwide, and thus HFC-based refrigerants, such as, for example, CFC 134a (1,1,1-tetrafluoroethane, CH2FCF3) has replaced many of the earlier CFC-based refrigerants. However, since HFC-based refrigerants have different chemical structure, they are not as easily mixed with lubrication fluids, such as, for example, oil, and have inferior abrasion resistance. Accordingly, when an HFC-based refrigerant is used in a compressor, performance of the compressor is degraded.
The exemplary rotary compressor shown in
The casing 10 includes a body 11 having a substantially cylindrical shape, with a driving motor 20 and a compression part 30 provided at upper and lower portions of the casing, and an upper cap 12 and a lower cap 13 which cover upper and lower ends of the body 11, respectively. A volume (V) from an upper end of the inner circumferential surface of the upper cap 12 to an upper end of the stator of the driving motor 20 is preferably formed to be more than 5000 mm3, thereby minimizing oil leakage.
As shown in
The stator 21 includes a stator laminator 25 which has a cylindrical shape so as to rotatably position the rotor 22 at the center thereof. A coil 26 is wound on the stator laminator 25 and connected to an external power source. The stator laminator 25 may form a ring shaped magnetic path, with a plurality of protruding poles 25a extending from an inner circumferential surface of the magnetic path at equal intervals. In certain embodiments, a distance between an upper end of the stator laminator 25 to a lower surface of an upper bearing plate, or main bearing 32 is approximately 110˜140 mm. In certain embodiments, a height difference between a center of a rotor laminator 27 in a shaft direction and a center of the stator laminator 25 in a shaft direction is within the range of −2˜3 mm, thereby preventing physical interference between the stator 21 and the rotor 22 due to an eccentric load on the rotation shaft 23.
The stator laminator 25 may include a rotor insertion hole 25b having a substantially circular shape at its center, with a plurality of protruding fixing portions 25c and cut-passages 25d alternately formed along an outer circumferential surface of the stator laminator 25 so as to form a gas passage F with the casing 10. In certain embodiments, the protruding fixing portions 25c and the cut-passages 25d may be symmetrical with each other, with the same interval therebetween. For example, a circumferential length between the protruding fixing portions 25c may be equal to a circumferential length between the cut-passages 25d so as to minimize any deformation of the stator laminator 25.
As shown in
The coil 26 may be successively wound on each of the protruding poles 25a of the stator laminator 25. The coil 26 may be implemented by forming an enamel coating layer having a separation transition temperature more than approximately 120° C. on an outer circumferential surface of a copper wire. An insulation film formed of, for example, a crystalline plastic film having a separation transition temperature more than approximately 50° C., may be interposed between an outer circumferential surface of the coil 26 and an inner circumferential surface of the stator laminator 25 contacting the coil 26.
The rotor 22 includes a rotor laminator 27. In certain embodiments, the rotor laminator 27 may be formed from a plurality of thin steel plates laminated in a shaft direction, with an upper end plate 28A and a lower end plate 28B disposed at upper and lower ends of the rotor laminator 27, respectively. Each steel plate of the rotor laminator 27 is provided with a shaft hole for insertion of the rotation shaft 23. In the embodiment shown in
A balance weight 29 eccentric at a certain angle in a circumferential direction is formed on the upper end plate 28A, either integrally or at a later point in fabrication. A thickness (t7) of the balance weight 29 may be less than two times the thickness (t5) of the upper end plate 28A so as to enhance reliability of the motor 20.
The upper and lower end plates 28A and 28B may either completely or partially cover the magnetic flux barriers 22a of the rotor 22 so as to form a path through the rotor 22 in the upper and lower directions.
The rotation shaft 23 may have a substantially circular section so as to fit into the shaft hole of the rotor 22. An oil hole 23a penetrates the length of the shaft 23, with an oil feeder 23b disposed at the lowest end of the oil hole 23a for drawing oil in from the casing 10. The rotation shaft 23 may be coupled to the shaft hole of the rotor 22 by numerous methods including, for example shrinkage fit of an outer diameter or shrinkage fit of an inner diameter. Deformation of the outer circumferential surface of the rotor 22, which in some instances is relatively weak, can be minimized by shrinkage fit of an inner diameter.
The rotation shaft 23 may include an eccentric portion 23c coupled to a rolling piston 34 at a lower outer circumferential surface thereof. In certain embodiments, the eccentric portion 23c is formed so that a ratio between a diameter (D1) of the shaft without the eccentric portion 23c and a diameter (D2) of the shaft 23 with the eccentric portion 23c can be 16:20˜18:30. In certain embodiments, the eccentric portion 23c is formed so that an eccentric amount thereof can be within a range of 1.5˜5 mm.
As shown in
In certain embodiments, the cylinder 31 has a ring shape with open upper and lower sides. The main bearing 32 and the sub bearing 33 each include a shaft hole for supporting the rotation shaft 23, and may have a disc shape to cover the open upper and lower sides of the cylinder 31. In certain embodiments, the cylinder 31, the main bearing 32, and the sub bearing 33 may be formed of gray pig iron, the rolling piston 34 may be formed of an alloy of molybdenum, nickel, and chrome, and the vane 35 may be formed of a high speed steel having undergone a nitriding process, thereby minimizing abrasion of the compression part. Other materials for these components may also be appropriate.
In certain embodiments, a diameter (D3) of the discharge port 32a may be approximately 5 mm when a volume of the compression chamber of the cylinder 31 is approximately 6 cc, and approximately 8 mm when the volume of the compression space is approximately 9 cc, thereby allowing for stable discharge of refrigerant. The muffler 37 may be coupled to an upper surface of the main bearing 32 by a bolt or other suitable fastener. For stability, a gap (t8) between an upper surface of the muffler 37 and a lower surface of the coil 26 is greater than 3.2 mm.
Operation of a rotary compressor as embodied and broadly described herein will now be explained.
When power is supplied to the stator 21 of the driving motor 20 and the rotor 22 is rotated, the rotation shaft 23 rotates to transmit a rotation force to the compression part 30. The rolling piston 34 rotates eccentrically in the cylinder 31, and refrigerant is drawn into a suction chamber through a refrigerant suction pipe SP connected to the cylinder 31. Then, the refrigerant is compressed and discharged into the casing 10 through the discharge port 32a.
In certain embodiments, the driving motor 20 is a synchronous reluctance motor which generates a rotation force by being synchronously rotated by a reluctance torque in a direction such that magnetic resistance is minimized. Accordingly, slippage between the stator 21 and the rotor 22 may be greatly reduced. Additionally, when an induction current flows into the rotor 22, thermal loss from the rotor 22 may be reduced to enhance efficiency of the motor 20.
Oil having acceptable mixture characteristics with a given refrigerant may be used, thereby preventing a ‘double-separation’ phenomenon in which the refrigerant and the oil are separated from each other at a sliding or friction portion of the compression part 30. Accordingly, frictional losses and abrasion of the compression part 30 can be reduced.
In order to ensure a continuous supply of oil to the compression part 30, oil is filled in the casing 10 to a height higher than the cylinder 31. An upper space of the casing 10 is established so that the refrigerant and oil discharged from the compression part 30 is not leaked to any portion of the refrigerating cycle after being separated in the inner space of the casing 10. Accordingly, abrasion of the compression part 30 due to oil leakage can be prevented.
Further, by minimizing the length of the rotor by sizing the various components and gaps therebetween as discussed above, interference between the stator 21 and the rotor 22 due to an eccentric load the rotation shaft 23 can be prevented.
In order to ensure that contraction of the stator laminator 25 in the radius direction is uniform if the stator 21 is shrinkage fit into the casing 10, the stator laminator 25 may be symmetrically formed, and a width of the stator laminator 25 and a length of the protruding fixing portion 25c may be sized to maintain a certain strength. Accordingly, the rotor insertion hole 25b of the stator laminator 25 maintains a substantially circular shape, and an air gap (t4) between the stator 21 and the rotor 22 is uniformly maintained, thereby preventing interference between the rotor 22 and the stator 21, and enhancing reliability of the driving motor 20 and the compressor.
The coil 26 may be implemented by forming an enamel coating layer on an outer circumferential surface of a copper wire, thereby preventing a voltage loss due to a hydrolysis, crack, softening, expansion, and breakdown. Also, an insulation film formed of a crystalline plastic film may be interposed between the coil 26 and an inner circumferential surface of the protruding pole 25a of the stator 21, thereby preventing any lowering in strength, tensile characteristics, or electrical insulating characteristics and enhancing reliability of the driving motor 20.
As discussed above, in certain embodiments, the rotor laminator 27 has a plurality of steel plates, and each of the magnetic flux barriers 27a has the same width (t1) from each end thereof to an outer circumferential surface of the steel plate, thereby facilitating fabrication.
Further, a width (t2) of the magnetic flux barrier 27a in the radius direction, and a width (t3) between adjacent magnetic flux barriers 27a in the radius direction are increased towards the center, thereby minimizing deformation of the steel plate when the rotation shaft 23 is shrinkage fit.
The rotor of the rotary compressor in accordance with another embodiment will now be explained.
In the aforementioned embodiment shown in
The rotor of a rotary compressor in accordance with another embodiment will now be explained.
In the aforementioned embodiments shown in
The casing 10, the driving motor 20, and the compression part 30 according to the second and third embodiments are similar to those of the first embodiment, and thus their details will be omitted.
When the width (t1) between an end of each of the magnetic flux barriers 27a and an outer circumferential surface of the steel plate is increased towards the center as shown in
In the preceding discussion, the aforementioned embodiments have been applied to a single rotary compressor having one cylinder. However, these embodiments may also be applied to a double-type rotary compressor as shown, for example, in
Each middle portion of the gas suction pipes SP1 and SP2 may be bent with different curvatures R1 and R2 so as to connect the cylinders 31 and 41 of the compression parts 30 and 40. In certain embodiments, the curvature R2 of the second gas suction pipe SP2 connected to the second compression part 40 far from the accumulator A is greater than the curvature R1 of the first gas suction pipe SP1, thereby enhancing reliability of the gas suction pipe SP2.
In the double-type rotary compressor, the length of the casing 10 may be longer than that of the single rotary compressor. Accordingly, a thickness (t9) of the base plate 1 for supporting the casing 10 on an installation surface may be increased. For instance, if a length L1 of the casing 10 is more than two times of an outer diameter (D4), the thickness (t9) of the base plate 1 may be 2.6˜4.0 mm to lend stability to the compressor.
When the rotary compressor in accordance with embodiments as broadly described herein is applied to an air conditioner, a thermal loss due to slippage of the driving motor is decreased, thus enhancing the function of the rotary compressor and the air conditioner. Furthermore, losses due to emissions are decreased, thus enhancing the function of the rotary compressor and the air conditioner having the same.
Further, when an eco-friendly refrigerant is used, oil easily mixed with the eco-friendly refrigerant has improved abrasion resistance and lubricating characteristics. Accordingly, reliability, durability and capacity of the rotary compressor and the air conditioner having the same is improved.
A compressor having a motor as embodied and broadly described herein has numerous applications in which compression of fluids is required, and in different types of compressors. Such applications may include, for example, air conditioning and refrigeration applications. One such exemplary application is shown in
Another such exemplary application is shown in
Another such exemplary application is shown in
Likewise, the motor as embodied and broadly described herein is not limited to installation in compressors. Rather, the motor as embodied and broadly described herein may be applied in any situation in which this type of driving force is required and/or advantageous.
An object is to provide a rotary compressor having a driving motor with high efficiency that is capable of generating less slip between a stator and a rotor, and generating less thermal loss at the rotor, and an air conditioner having the same.
Another object is to provide a rotary compressor capable of enhancing a function thereof by using an eco-friendly refrigerant and a driving motor of a high efficiency, and an air conditioner having the same.
Still another object is to provide a rotary compressor capable of enhancing a reliability thereof by using an eco-friendly refrigerant, by using oil easily mixed with the eco-friendly refrigerant, having an excellent abrasion resistance and lubricating characteristic, and not badly influencing on an insulating material, a drying material, etc., by using a driving motor suitable for the eco-friendly refrigerant and the oil, and an air conditioner having the same.
To achieve these and other advantages and in accordance with embodiments broadly described herein, there is provided a rotary compressor, including a casing having a hermetic inner space for filling a certain amount of oil, and to which gas suction pipe and a gas discharge pipe are connected, a driving motor installed at the inner space of the casing, and synchronously rotated by a reluctance torque in a direction that a magnetic resistance is minimized, at least one cylinder fixed at the inner space of the casing so as to be positioned at one side of the driving motor in a shaft direction, and to which the gas suction pipe is directly connected, for compressing a refrigerant, a plurality of bearing plates covering the cylinder thereby forming a compression space, for supporting a rotation shaft of the driving motor, at least one rolling piston orbit-motioned in the compression space of the cylinder, coupled to an eccentric portion of the rotation shaft, and linearly-contacting an inner circumferential surface of the cylinder, for flowing a refrigerant, and at least one vane contacting the rolling piston, for dividing the compression space into a suction chamber and a compression chamber, wherein a hydro-fluorocarbon (HFC) or hydro-chlorofluorocarbon (HCFC)-based refrigerant is used, wherein fatty acid-ester oil is used in the even of the HFC-based refrigerant, and fatty acid-mineral oil is used in the event of the HCFC-based refrigerant, the fatty-acid ester oil having a viscosity of 2˜70 cSt at a temperature of 40° C., having a viscosity of 1˜9 cSt at a temperature of 100° C., and ester-coupled in a molecule at least two times, the fatty-acid mineral oil having a viscosity of 32˜68 cSt at a temperature of 40° C. and ester-coupled in a molecule at least two times, wherein the driving motor includes a stator formed accordingly as a plurality of steel plates are laminated thus to be inserted into an inner circumferential surface of the casing, the steel plate having a plurality of protruding poles on which a field coil is wound, a rotor formed accordingly as a plurality of steel plates are laminated thus to be rotatably disposed in the stator, the steel plate having a plurality of magnetic flux barriers penetratingly formed in a shaft direction, in which a width of the magnetic flux barrier in a radius direction and a width between the magnetic flux barriers in the radius direction are increased towards the center of the driving motor, and a rotation shaft coupled to the center of the rotor by shrinkage fit thus to be supported by a frame, one end of the rotation shaft is coupled to the orbit scroll, wherein an insulation film formed of a crystalline plastic film having a separation transition temperature more than 50° C. is disposed between the stator of the driving motor and the field coil, and wherein the field coil is implemented by forming an enamel coating layer having a separation transition temperature more than 120° C.
Any reference in this specification to “one embodiment,” “an exemplary,” “example embodiment,” “certain embodiment,” “alternative embodiment,” and the like means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment as broadly described herein. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with any embodiment, it is submitted that it is within the purview of one skilled in the art to effect such feature, structure, or characteristic in connection with other ones of the embodiments.
Although embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More particularly, numerous variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art.