Patent Application
20170089341
The present invention relates to a scroll compressor and a method of manufacturing the same, and particularly relates to the structure of a balancer.
Conventionally, two balancers or more have been attached to a main shaft of a scroll compressor to compensate centrifugal force of an eccentrically orbiting spiral of oscillatory movement. Each balancer has, for example, a semi-circular shape or a fan shape in plan view to achieve eccentricity of a barycenter. Thus, rotation of the balancer agitates surrounding fluid, causing the following problems.
When the balancer is arranged below a main bearing, oil dropped from the main bearing is scattered in the form of mist by rotation of the balancer and is moved to the compressor together with refrigerant, resulting in an increase of oil loss. When the balancer is arranged in a frame above the main bearing, the balancer rotates in a space filled with oil, which leads to power loss due to agitation of the oil.
To solve the above-described problems, a scroll compressor is disclosed in which the agitation of fluid by the balancer is prevented (for example, refer to Patent Literature 1).
In Patent Literature 1, the balancer has an outline in a cylinder shape that is circular in plan view, and a hollow space is provided in the balancer to secure centrifugal force necessary for balancing with the centrifugal force of the orbiting spiral, and prevent agitation of surrounding fluid.
Patent Literature 1: Japanese Patent Laid-open No. 2002-031070 (for example, refer to [0016] and FIG. 2)
However, in Patent Literature 1, the hollow space is provided inside each balancer to achieve the eccentricity of its barycenter, and thus, when the balancer is disposed in a space filled with oil, the oil flows into the hollow space. This leads to a difference in the centrifugal force generated to the balancer from a designed value, causing a problem of increasing vibration.
The present invention is intended to solve the above-described problems, and it is an object of the present invention to provide a scroll compressor capable of preventing agitation of fluid and an increase in vibration, and a method of manufacturing the same.
A scroll compressor according to one embodiment of the present invention includes a fixed scroll including a spiral unit, an orbiting scroll including a spiral unit and combined with the spiral unit of the fixed scroll to form a compression chamber for compressing refrigerant, a main shaft for transmitting drive power to the orbiting scroll, an electric motor unit configured to rotate the main shaft, and a first balancer for compensating unbalance of the orbiting scroll with respect to a rotation center of the main shaft. The first balancer has an outline in a cylinder shape, and includes a high-density part made of a high-density material, and a low-density part made of a low-density material having a density lower than a density of the high-density material,
In a scroll compressor according to one embodiment of the present invention, a balancer has an outline in a cylinder shape, which can prevent agitation of surrounding fluid when the balancer rotates. Moreover, no hollow space for eccentricity of a barycenter is provided inside the balancer, causing no difference in centrifugal force generated to the balancer from a designed value, and preventing an increase in vibration.
Embodiments of the present invention will be described below with reference to the accompanying drawings. Those embodiments described below are not intended to limit the present invention. A relation between the sizes of components in the drawings described below is different from the actual relation in some cases.
The following first describes the structure of a scroll compressor 100 according to the present Embodiment 1.
The scroll compressor 100 is configured to suck and compress refrigerant circulating in a refrigeration cycle, and discharge the refrigerant at high temperature and high pressure. As illustrated in
The shell is a pressure resisting container including a middle shell 25 having a cylinder shape, a lower shell 26 sealed to an opening on a lower surface of the middle shell 25 by, for example, welding, and an upper shell 24 sealed to an upper surface opening of the middle shell 25 by, for example, welding.
The middle shell 25 is connected with a suction pipe 7 formed as part of a refrigerant circuit and configured to suck the refrigerant into the shell, and includes a frame 6 fixed to an inner periphery of an upper end part, and a stator 11 fixed to an inner periphery of a middle part. A bottom part of the lower shell 26 serves as an oil reservoir 18 that accumulates therein oil for lubricating each bearing. A bottom surface of the frame 6 is connected with an oil discharge pipe 8 for returning oil accumulated in the frame 6 to the oil reservoir 18. The upper shell 24 is connected with a discharge pipe 1 for discharging compressed refrigerant from the shell to the refrigerant circuit.
The compression mechanism unit includes at least a fixed scroll 4 provided with a spiral unit 4a on one of its surfaces, an orbiting scroll 5 provided with, on one of its surfaces, a spiral unit 5a having a spiral direction opposite to that of the fixed scroll 4, an orbiting bearing 21 provided opposite to a compression chamber with reference to the orbiting scroll 5 and supported to orbit freely by an eccentric slider shaft portion 14a, the frame 6 to which the fixed scroll 4 is fixed and that is provided with a main bearing 19 in a central part, and a main shaft 14 through which a rotor 12 adhered to an outer periphery transmits drive power to the orbiting scroll 5. The compression mechanism unit is coupled with the electric motor unit and configured to compress the refrigerant.
The eccentric slider shaft portion 14a is a slider mounting shaft installed on an upper part of the main shaft 14 to achieve eccentricity of a slider 22 with respect to the main shaft 14.
The spiral units 4a and 5a are combined with each other to form a plurality of compression chambers (not illustrated) between the fixed scroll 4 and the orbiting scroll 5. To reduce refrigerant leaked from an apical surface of the spiral unit 4a of the fixed scroll 4 and an apical surface of the spiral unit 5a of the orbiting scroll 5, sealing (not illustrated) is provided to the apical surface of the spiral unit 4a of the fixed scroll 4 and the apical surface of the spiral unit 5a of the orbiting scroll 5.
A discharge port 28 for discharging refrigerant gas compressed to high pressure is formed in a central part of the fixed scroll 4. The refrigerant gas compressed to high pressure is ejected into a high pressure part (not illustrated) in the upper shell 24. The refrigerant gas ejected into the high pressure part is discharged into the refrigeration cycle through the discharge pipe 1. The discharge port 28 is provided with a discharge valve 29 for preventing backflow of refrigerant from the high pressure part to the discharge port 28.
The electric motor unit includes the rotor 12 fixed to the main shaft 14 and the stator 11 fixed to the middle shell 25. The electric motor unit is configured to be driven at start of power supply to the stator 11 and rotate the main shaft 14, causing the orbiting scroll 5 to perform orbiting movement through the main shaft 14.
The scroll compressor 100 includes a thrust plate 30 as a thrust bearing that supports the orbiting scroll 5 in an axial center direction, an Oldham's coupling 23 supported to orbit freely by the frame 6 to prevent spin of the orbiting scroll 5 and provide orbiting movement, the slider 22 that supports the orbiting scroll 5 to allow the orbiting scroll 5 to orbit, a sleeve 20 provided near the eccentric slider shaft portion 143 to smoothly rotate the main bearing 19 of the frame 6 and the main shaft 14, and a first balancer 27 and a second balancer 13 for compensating unbalance of the orbiting scroll 5 performing orbiting movement through the eccentric slider shaft portion 14a, with respect to a rotation center of the main shaft 14. The first balancer 27 is provided above the electric motor unit, whereas the second balancer 13 is provided below the electric motor unit.
The main shaft 14 rotates with rotation of the rotor 12 to cause the orbiting scroll 5 to orbit. The upper part of the main shaft 14 is supported by the main bearing 19 formed in the frame 6. A lower part of the main shaft 14 is rotatably supported by a sub bearing 16 formed in a central part of a sub frame 15 provided to a lower part of the shell. The sub bearing 16 has its outer ring fitted by pressing in a bearing housing part formed in the central part of the sub frame 15.
The sub frame 15 is provided with a displacement oil pump 17 configured to pump oil from the oil reservoir 18 in the bottom part of the shell and supply the oil to each sliding unit, and a pump shaft portion 14b for transmitting rotational force to the oil pump 17 is integrally formed the main shaft 14.
The main shaft 14 includes inside a vertical lubricating hole 14c that penetrates from a lower end of the pump shaft portion 14b to an upper end of the eccentric slider shaft portion 14a in the vertical direction (axial direction) and supplies oil o bearings and sliding units of the compression mechanism unit.
The first balancer 27 includes a high-density part 10 and a low-density part 9 having a density lower than that of the high-density part 10, and is formed by attaching the high-density part 10 to the low-density part 9. The first balancer 27 has an outline in a cylinder shape not to agitate surrounding fluid when rotating. The high-density part 10 is made of a high-density material such as metal, and the low-density part 9 is made of a low-density material such as resin material. With this configuration, the first balancer 27 has a barycenter that is eccentric toward the high-density part 10, and is capable of generating centrifugal force necessary as a balancer. The first balancer 27 is substantially solid inside and has an extremely small hollow space to prevent generation of a difference in centrifugal force due to oil flowed into the first balancer 27.
The following describes an operation of the scroll compressor 100.
In the scroll compressor 100 configured as described above, when the stator 11 is supplied with power, the rotor 12 is rotated by rotational force from a rotating magnetic field generated by the stator 11, and the main shaft 14 is rotated by the rotation of the rotor 12.
When the main shaft 14 is rotated, the eccentric slider shaft portion 14a is rotated in the orbiting bearing 21 through the slider 22, transmitting drive power to the orbiting scroll 5. Simultaneously, the orbiting scroll 5 performs orbiting movement while being prevented from spinning by the Oldham's coupling 23 reciprocating inside an Oldham groove (not illustrated) of the orbiting scroll 5 housing a key part (not illustrated) formed on one of surfaces of the Oldham's coupling 23, and an Oldham groove (not illustrated) of the frame 6 housing a key part (not illustrated) formed on the other surface of the Oldham's coupling 23. The frame 6 and the sub frame 15 are fixed inside the shell, and thus an accuracy variation of the fixation and an accuracy variation in an individual component lead to an axial center difference between the main bearing 19 and the sub bearing 16. Because of these accuracy variations as well as deflection of the main shaft 14, the main bearing 19 and the main shaft 14, and the sub bearing 16 and the main shaft 14 are not always parallel to each other.
To provide parallelism to a sliding surface of the main bearing 19, the sleeve 20 is housed between the main shaft 14 and the main bearing 19. When the axial center difference exits between the main bearing 19 and the sub bearing 16, the main shaft 14 is tilted to the main bearing 19, but this tilt of the main shaft 14 is canceled by a pivot part (not illustrated) of the main shaft 14 in contact with an inner periphery of the sleeve 20. Accordingly, an outer periphery of the sleeve 20 is always slidable in parallel with the main bearing 19.
Centrifugal force is generated to the orbiting scroll 5 by its orbiting movement, causing the eccentric slider shaft portion 14a of the main shaft 14 to slide within a slidable range of a sliding surface (not illustrated) of the slider 22. Then, the spiral unit 5a of the orbiting scroll 5 and the spiral unit 4a of the fixed scroll 4 become in contact with each other to form a compression chamber. The centrifugal force of the orbiting scroll 5 and a load in the radial direction generated to compress refrigerant act on the eccentric slider shaft portion 14a of the main shaft 14, and accordingly, in some cases, the eccentric slider shaft portion 14a becomes deflected to be not parallel to an inner surface of the orbiting bearing 21 provided in a central part of a lower surface of the orbiting scroll 5.
To provide parallelism to a sliding surface in the orbiting bearing 21, the slider 22 is housed between the eccentric slider shaft portion 14a of the main shaft 14 and the orbiting bearing 21. Thus, the tilt of the eccentric slider shaft portion 14a of the main shaft 14 with respect to the orbiting bearing 21, which is caused by the deflection of the eccentric slider shaft portion 14a, is canceled by a pivot part (not illustrated) of the eccentric slider shaft portion 14a in contact with the sliding surface of the slider 22. Accordingly, an outer periphery of the slider 22 is always slidable in parallel with the orbiting bearing 21.
The refrigerant in the refrigerant circuit is sucked into the shell through the suction pipe 7, and flows, through a suction port (not illustrated) of the frame 6, into the compression chamber formed by the spiral unit 5a of the orbiting scroll 5 and the spiral unit 4a of the fixed scroll 4. The compression chamber is moved toward the center of the orbiting scroll 5 by the orbiting movement of the orbiting scroll 5, and the refrigerant is thereby reduced in volume to be compressed. In this process, the compressed refrigerant applies a load to separate the fixed scroll 4 and the orbiting scroll 5 from each other, but this load on the orbiting scroll 5 is supported by a bearing formed by the orbiting bearing 21 and the thrust plate 30. The compressed refrigerant passes through the discharge port 28 of the fixed scroll 4, pushes to open the discharge valve 29, and passes through the high pressure part in the upper shell 24, before being discharged from the shell to the refrigerant circuit through the discharge pipe 1.
In the above-described series of operations, the oil pump 17 is driven by the pump shaft portion 14b of the main shaft 14 in rotation to pump oil from the oil reservoir 18 at the bottom part of the shell through the vertical lubricating hole 14c. The pumped oil is supplied to the main bearing 19, the sub bearing 16, and the orbiting bearing 21. Then, the oil lubricates the main bearing 19 and the sub bearing 16 and drops down back to the oil reservoir 18 at the bottom of the shell. Oil having lubricated the orbiting bearing 21 is stored in a space 6a in the frame. The oil in the space 6a in the frame is supplied to the thrust bearing, the Oldham's coupling 23, the spiral units 4a and 5a, and the main bearing 19, and also used to, for example, cool the orbiting bearing 21 and the main bearing 19. The space 6a in the frame is provided with the oil discharge pipe 8, through which excessive oil is returned to the oil reservoir 18 at the bottom part of the shell from the space 6a in the frame.
The following describes the first balancer 27 according to the present Embodiment 1.
The low-density part 9 of the first balancer 27 includes a low-density main part 9c and a cover part 9d, and is provided with a shaft hole 9a through which the main shaft 14 is provided, a high-density part housing hole 9b for housing the high-density part 10, and a low-density part fastening hole 9e for fastening with the high-density part 10. The low-density part 9 has an outline in a cylinder shape with hollowed parts corresponding to the shaft hole 9a, the high-density part housing hole 9b, and the low-density part fastening hole 9e.
A high-density part fastening hole 10a for fastening with the low-density part 9 is formed in the high-density part 10 of the first balancer 27, and the high-density part 10 is fitted into the high-density part housing hole 9b of the low-density part 9 while positions of the high-density part fastening hole 10a and the low-density part fastening hole 9e of the low-density part 9 are aligned. In this fitting, it may be preferable to have a clearance of 1 mm or less between the high-density part 10 and the high-density part housing hole 9b of the low-density part 9 to uniquely determine the positional relation between the high-density part 10 and the low-density part 9 without a large variation. After the fitting, the low-density part 9 and the high-density part 10 are fastened to the low-density part fastening hole 9e and the high-density part fastening hole 10a through a first fastening member 2 such as a bolt or a rivet.
The high-density part 10 is supported by the low-density part 9 through frictional force between the cover part 9d of the low-density part 9 and a fastening surface of the high-density part 10, and thus, centrifugal force generated by the first balancer 27 in rotation prevents shifting of the low-density part 9 and the high-density part 10 from each other. This can prevent oil from flowing into the first balancer 27, thereby preventing a difference in centrifugal force.
As described above, the first balancer 27 according to the present Embodiment 1 has an outline in a cylinder shape, and thus can prevent agitation of surrounding fluid when rotating. The first balancer 27 includes the low-density part 9 and the high-density part 10, and thus has a barycenter that is eccentric toward the high-density part 10, thereby generating centrifugal force necessary as a balancer. The configuration of the first balancer 27 is substantially solid inside and has a small hollow space, preventing generation of a difference in centrifugal force due to oil flowing into the first balancer 27. This can prevent a difference in centrifugal force generated to the balancer from a designed value, and prevent an increase in vibration.
The following describes the present Embodiment 2. Any description duplicating with that in Embodiment 1 will be omitted, and any part identical or equivalent to that in Embodiment 1 will be denoted by the same reference numeral.
In the present Embodiment 2, the compression mechanism unit is provided with the balancer-attached slider ASSY 40. The balancer-attached slider ASSY 40 includes a balancer-attached slider 40a in which a slider 40d is attached to a high-density balancer 40f, and a low-density part 40b attached to the balancer-attached slider 40a. The balancer-attached slider 40a rotates in a space filled with oil, and thus reduction in an oil scattering loss can be achieved by attaching the low-density part 40b to the balancer-attached slider 40a.
As illustrated in
Fig, 6 is a diagram illustrating prevention of turnover of the balancer-attached slider ASSY 40 of the scroll compressor 100 according to Embodiment 2 of the present invention.
When a parallel sliding bearing is used as the orbiting bearing 21, an action central point of orbiting bearing reaction force exists at a position in a height direction of the center of the orbiting bearing 21. When a position in a height direction of an action central point of centrifugal force of the entire balancer-attached slider ASSY 40 is set to be equal to the position in the height direction of the center of the orbiting bearing, the centrifugal force (arrow α 41) and the orbiting bearing reaction force (arrow β 42) act at the same position in the height direction, preventing generation of a moment to turn over the balancer-attached slider ASSY 40. This configuration can prevent partial contact of the orbiting bearing 21, thereby securing the reliability of the orbiting bearing 21. When the balancer-attached slider 40a is covered by a hollow cover, centrifugal force applied to oil flowing into the cover adversely generates a moment to turn over the balancer-attached slider 40a, which is, however, not the case with the present Embodiment 2.
The following describes the present Embodiment 3. Any description duplicating with that in Embodiment 1 will be omitted, and any part identical or equivalent to that in Embodiment 1 will be denoted by the same reference numeral.
In the present Embodiment 3, as illustrated in
Even when the scroll compressor 100 is operated while refrigerant is accumulated and the second balancer 13 is immersed in a mixture of liquid refrigerant and oil, the oil and the liquid refrigerant do not flow into the second balancer 13, causing no difference in centrifugal force of the second balancer 13 from a designed value, and preventing an increase in vibration.
A high-density part fastening hole 52a is formed in the high-density part 52 of the second balancer 13, and a low-density part fastening hole 51a is formed in the low-density part 51 of the second balancer 13. A shaft hole 50 is formed by the high-density part 52 and the low-density part 51. A second fastening member 3 such as a bolt or a rivet is provided through the high-density part fastening hole 52a and the low-density part fastening hole 51a to swage the high-density part 52 and the low-density part 51 together with the rotor 12, thereby attaching the second balancer 13 to the rotor 12. This assembly can achieve a high productivity.
As illustrated in
The following describes the present Embodiment 4. Any description duplicating with that in Embodiment 1 will be omitted, and any part identical or equivalent to that in Embodiment 1 will be denoted by the same reference numeral.
1 discharge pipe 2 first fastening member 3 second fastening member 4 fixed scroll 4a spiral unit (fixed scroll) 5 orbiting scroll 5a spiral unit (orbiting scroll) 6 frame 6a space in the frame 7 suction pipe 8 oil discharge pipe 9 low-density part (first balancer) 9a shaft hole 9b high-density part housing hole 9c low-density main part 9d cover part 9e low-density part fastening hole 10 high-density part 10a high-density part fastening hole 11 stator 12 rotor 13 second balancer 14 main shaft 14a eccentric slider shaft portion 14b pump shaft portion 14c vertical lubricating hole 15 sub frame 16 sub bearing 17 oil pump oil reservoir 19 main bearing 20 sleeve 21 orbiting bearing 22 slider 23 Oldham's coupling 24 upper shell 25 middle shell 26 lower shell 27 first balancer 28 discharge port 29 discharge valve 30 thrust plate 40 balancer-attached slider ASSY 40a balancer-attached slider 40b low-density part 40c oil drain gap 40d slider 40e eccentric slider fitting hole 40f balancer 50 shaft hole 41 arrow α 42 arrow β 51 low-density part (second balancer) 51 a low-density part fastening hole 52 high-density part (second balancer) 52a high-density part fastening hole 100 scroll compressor
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2014/066215 | 6/18/2014 | WO | 00 |
