1. Field
The present invention relates to a compressor, and more particularly, to a compressor and an air conditioner having the same.
2. Background
In general, a compressor converts mechanical energy into compressive energy. Compressors may be categorized into a reciprocating type, a scroll type, a centrifugal type, a rotary type and a vane type. The scroll 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 can generate heat, which lowers efficiency due to thermal losses.
The embodiments will be described in detail with reference to the following drawings in which like reference numerals refer to like elements, and wherein:
Reference will now be made in detail to preferred embodiments, examples of which are illustrated in the accompanying drawings.
A compressor and components thereof in accordance with embodiments as broadly described herein are shown in
Some compressors have used a chlorofluorocarbon (CFC)-based refrigerant such as 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. In addition, they may have inferior abrasion resistance. Accordingly, when an HFC-based refrigerant is used in a compressor, performance of the compressor is typically degraded.
The exemplary compressor shown in
The casing 20 includes a body 11 having a substantially cylindrical shape. The driving motor 20 and the compression device 30 are provided at lower and upper portions of the casing, respectively. An upper cap 12 and a lower cap 13 cover upper and lower ends of the body 11. The body 11 is formed with a cylindrical shape, and the upper and lower ends have substantially the same diameter. However, when an outer diameter (D1) of the driving motor 20 is larger than an outer diameter of the compression device 30 (in this embodiment, an outer diameter of a plate portion of a fixed scroll), a stepped portion may be formed between the driving motor 20 and the compression device 30.
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. As shown in
The stator laminator 25 may include a rotor insertion hole 25b having a substantially circular shape at its center. A plurality of protruding fixing portions 25c and cut-passages 25d are alternately formed along an outer circumferential surface of the stator laminator 25 so as to form a gas passage F with the casing 10.
As shown in
A ratio (d1/w1) between a diameter (d1) of the rotor insertion hole 25b and a width (w1) of the stator laminator 25 may be greater than or equal to 2.1. Additionally, an angle θ formed between both ends of the protruding fixing portion 25c and a center of the stator 21 may be 15°˜35°. In certain embodiments, at least two cut-passages 25d are formed so that a ratio (QA0/QA1) between a sum (QA0) of a circumferential length of each cut-passage 25d and a sum (QA1) of a circumferential length of each protruding fixing portion 25c is 0.2˜0.8.
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 with a copper wire having an enamel coating layer with a separation transition temperature of more than approximately 120° C. formed on an outer circumferential surface of the copper wire. An insulation film formed of a crystalline plastic film having a separation transition temperature of more than approximately 50° C. may be interposed between an outer circumferential surface of the coil and an inner circumferential surface of the stator laminator 25 contacting the coil. The coil 26 is formed so as to have a height H1 corresponding to 1.5˜3 times of the height H2 of the stator laminator 25.
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.
In the embodiment shown in
As shown in
The steel plate constituting the stator laminator 25 of the driving motor 20 or the rotor laminator 27 may have a thickness of less than 1/100 of the total heights of the stator and rotor, respectively. The rotor laminator 27 is formed so that its height (H3) may be 3˜7 times of a wrap height (H4) of a fixed scroll 31 and an orbiting scroll 32.
The upper and lower end plates 28A and 28B are respectively formed to have a thickness (t5) of approximately 1˜4 mm. 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 (t6) 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 27a 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 cross-section so as to fit into the shaft hole of the rotor 22. An oil hole 23a penetrates the length of the shaft 23. An oil feeder 23b, which may be implemented as a Trochoid pump, is 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 is formed so that its length may be 2˜6 times of a height of the rotor laminator 27, and so that its diameter (D4) may be 1/6˜¼ times a diameter (D5) of a plate portion of a fixed scroll 31.
In this embodiment, the compression part 30 includes a fixed scroll 31 fixed on an upper surface of a main frame 1 and an orbiting scroll 32 orbitably disposed on an upper surface of the main frame 1 so as to form a plurality of compression chambers P by being engaged with the fixed scroll 31. An Oldham's ring 33 is disposed between the orbiting scroll 32 and the main frame 1, for orbiting the orbiting scroll 32 and preventing a rotation of the orbiting scroll 32. A high/low pressure separating plate 34 is installed at a rear surface of the plate portion of the fixed scroll 31, for dividing the inside of the casing 10 into a high pressure portion and a low pressure portion. A backflow preventing valve 35 acts to prevent backflow of discharge gas by opening and closing a discharge port 31c of the fixed scroll 31.
The fixed scroll 31 includes a fixed wrap 31, which is an involutely formed at a lower surface of the plate portion and which constitutes one pair of compression chambers P. An inlet 31b is formed at a side surface of the plate portion and is connected to the suction pipe SP. A discharge port 31c formed at the center of an upper surface of the plate portion and is connected to the center of the fixed wrap 31a, for discharging compressed gas the upper portion of the casing 10.
The orbiting scroll 32 includes an orbiting wrap 32, which is an involutely formed on an upper surface of the plate portion, and which constitutes one pair of compression chambers P together with the fixed wrap 31a. A boss portion 32b is formed at the center of a lower surface of the plate portion for receiving a driving force of the driving motor 20 by being coupled to the rotation shaft 23. A back pressure chamber 1a is formed on an upper surface of the main frame 1 and supports the orbiting scroll 32 and contains oil therein. The back pressure chamber 1a is formed at a position where its outer diameter P6) is smaller than an outer diameter P2) of the rotor of the driving motor 20 so as to stabilize the operation of the orbiting scroll 32.
The fixed scroll 31 and the orbiting scroll 32 are formed by a casting method. Either the fixed scroll 31 and/or the orbiting scroll 32 may be solid-lubrication processed using a solid lubricant such as MoS2 and Lub so as to reduce a frictional loss. The orbiting scroll 32 may be formed of a material having a weight less than that of the fixed scroll 31 so as to improve efficiency of the driving 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.
When a hydro-fluorocarbon (HFC) based-refrigerant is used, fatty-acid ester oil is used for lubrication. Also, when a hydro-chlorofluorocarbon (HCFC)-based refrigerant is used, fatty-acid mineral oil is used for lubrication. The fatty-acid ester oil typically has a viscosity of 2˜70 cSt at a temperature of 40° C., and a viscosity of 1˜9 cSt at a temperature of 100° C., and is ester-coupled in a molecule at least two times. The fatty-acid mineral oil typically has a viscosity of 32˜68 cSt at a temperature of 40° C. and is ester-coupled in a molecule at least two times.
In order to ensure a continuous supply of oil to the compression part 30, oil is filled in the casing 10 to a height lower than a lowest end of the stator 21. Further, by minimizing the length of the rotor, and 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 on the rotation shaft 23 can be prevented.
A bearing 2 supporting a lower end of the rotating shaft 23 is mounted on the bottom of the casing 10. When power is supplied to the driving motor 20, and the rotation shaft 23 rotates together with the rotor 22, the orbiting scroll 32 moves in an orbital fashion on an upper surface of the main frame 1, as guided by the Oldham ring 33. One pair of compression chambers P are consecutively moved between the orbiting wrap 32a of the orbiting scroll 32 and the fixed wrap 31a of the fixed scroll 31. As the orbiting scroll 32 continuously orbits, the compression chambers P have a decreased volume, thereby sucking, compressing, and discharging refrigerant gas.
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.
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 between the stator 21 and the rotor 22 is uniformly maintained. This prevents interference between the rotor 22 and the stator 21, and enhances 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 hydrolysis, cracking, softening, expansion, and/or 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 poles 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 is comprised of a plurality of steel plates. In some embodiments, the steel plates are formed such that a distance (t1) from ends of the magnetic flux barriers 27a to an outer circumferential surface of the steel plate is substantially the same for all of the magnetic flux barriers. Further, a width (t2) of the magnetic flux barriers 27a in the radius direction, and a separation distance (t3) between adjacent magnetic flux barriers 27a in the radius direction increases towards the center. This helps to minimize deformation of the steel plate when the rotation shaft 23 is shrinkage fit into the rotor laminator 27.
In the aforementioned embodiment shown in
In yet another alternate embodiment, as shown in
When the distance (t1) between an end of each of the magnetic flux barriers 27a and an outer circumferential surface of the steel plate varies as shown in
When the a 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 compressor and the air conditioner. Furthermore, losses due to emissions are decreased, thus enhancing the function of the 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 scroll compressor and the air conditioner having the same is improved.
A compressor having an oil pumping system 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
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 affect 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. 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.