US20170089341A1

US20170089341A1 - Scroll compressor and method of manufacturing the same

Info

Publication number: US20170089341A1
Application number: US15/311,868
Authority: US
Inventors: Yuji Takamura
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2014-06-18
Filing date: 2014-06-18
Publication date: 2017-03-30
Also published as: JP6257765B2; WO2015194000A1; JPWO2015194000A1

Abstract

A scroll compressor 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.

Description

TECHNICAL FIELD

The present invention relates to a scroll compressor and a method of manufacturing the same, and particularly relates to the structure of a balancer.

BACKGROUND ART

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.

CITATION LIST

Patent Literature

Patent Literature 1: Japanese Patent Laid-open No. 2002-031070 (for example, refer to [0016] and FIG. 2)

SUMMARY OF INVENTION

Technical Problem

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.

Solution to Problem

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,

Advantageous Effects of Invention

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.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a vertical sectional view of a scroll compressor according to Embodiment 1 of the present invention.

FIGS. 2(a) and 2(b) are each a diagram illustrating a low-density part of a first balancer of the scroll compressor according to Embodiment 1 of the present invention.

FIGS. 3(a) and 3(b) are each a diagram illustrating a method of assembling the first balancer of the scroll compressor according to Embodiment 1 of the present invention.

FIG. 4 is an enlarged view of the vicinity of a balancer-attached slider ASSY of a scroll compressor according to Embodiment 2 of the present invention.

FIGS. 5(a) and 5(b) are each a diagram illustrating the balancer-attached slider ASSY of the scroll compressor according to Embodiment 2 of the present invention.

FIG. 6 is a diagram illustrating prevention of turnover of the balancer-attached slider ASSY of the scroll compressor according to Embodiment 2 of the present invention.

FIG. 7 is a vertical sectional view of a scroll compressor according to Embodiment 3 of the present invention.

FIGS. 8(a) and 8(b) are each a diagram illustrating a method of attaching, to a rotor, a second balancer of the scroll compressor according to Embodiment 3 of the present invention.

FIG. 9 is an enlarged view of the vicinity of the second balancer of the scroll compressor according to Embodiment 3 of the present invention.

FIG. 10 is a vertical sectional view of a scroll compressor according to Embodiment 4 of the present invention.

DESCRIPTION OF EMBODIMENTS

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.

Embodiment 1

The following first describes the structure of a scroll compressor 100 according to the present Embodiment 1.
FIG. 1 is a vertical sectional view of the scroll compressor 100 according to Embodiment 1 of the present invention.
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 FIG. 1, the scroll compressor 100 includes a compression mechanism unit and an electric motor unit in a shell, where the compression mechanism unit is arranged on an upper side, and the electric motor unit is arranged on a lower side.
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 4 a on one of its surfaces, an orbiting scroll 5 provided with, on one of its surfaces, a spiral unit 5 a 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 14 a, 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 14 a 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 4 a and 5 a 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 4 a of the fixed scroll 4 and an apical surface of the spiral unit 5 a of the orbiting scroll 5, sealing (not illustrated) is provided to the apical surface of the spiral unit 4 a of the fixed scroll 4 and the apical surface of the spiral unit 5 a 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 14 a, 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 14 b 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 14 c that penetrates from a lower end of the pump shaft portion 14 b to an upper end of the eccentric slider shaft portion 14 a 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 14 a 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 14 a 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 5 a of the orbiting scroll 5 and the spiral unit 4 a 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 14 a of the main shaft 14, and accordingly, in some cases, the eccentric slider shaft portion 14 a 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 14 a of the main shaft 14 and the orbiting bearing 21. Thus, the tilt of the eccentric slider shaft portion 14 a of the main shaft 14 with respect to the orbiting bearing 21, which is caused by the deflection of the eccentric slider shaft portion 14 a, is canceled by a pivot part (not illustrated) of the eccentric slider shaft portion 14 a 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 5 a of the orbiting scroll 5 and the spiral unit 4 a 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 14 b 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 14 c. 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 6 a in the frame. The oil in the space 6 a in the frame is supplied to the thrust bearing, the Oldham's coupling 23, the spiral units 4 a and 5 a, and the main bearing 19, and also used to, for example, cool the orbiting bearing 21 and the main bearing 19. The space 6 a 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 6 a in the frame.
The following describes the first balancer 27 according to the present Embodiment 1.
FIGS. 2(a) and 2(b) are each a diagram illustrating the low-density part 9 of the first balancer 27 of the scroll compressor 100 according to Embodiment 1 of the present invention. FIG. 2(a) is a plan view of the low-density part 9 of the first balancer 27, and FIG. 2(b) is a sectional view taken along line A-A in FIG. 2(a).
The low-density part 9 of the first balancer 27 includes a low-density main part 9 c and a cover part 9 d, and is provided with a shaft hole 9 a through which the main shaft 14 is provided, a high-density part housing hole 9 b for housing the high-density part 10, and a low-density part fastening hole 9 e 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 9 a, the high-density part housing hole 9 b, and the low-density part fastening hole 9 e.
FIGS. 3(a) and 3(b) are each a diagram illustrating a method of assembling the first balancer 27 of the scroll compressor 100 according to Embodiment 1 of the present invention. FIG. 3(a) illustrates the first balancer 27 before assembly, and FIG. 3(b) illustrates the first balancer 27 after assembly.
A high-density part fastening hole 10 a 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 9 b of the low-density part 9 while positions of the high-density part fastening hole 10 a and the low-density part fastening hole 9 e 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 9 b 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 9 e and the high-density part fastening hole 10 a 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 9 d 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.

Embodiment 2

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.
FIG. 4 is an enlarged view of the vicinity of a balancer-attached slider ASSY 40 of the scroll compressor 100 according to Embodiment 2 of the present invention. FIGS. 5(a) and 5(b) are each a diagram illustrating the balancer-attached slider ASSY 40 of the scroll compressor 100 according to Embodiment 2 of the present invention. FIG. 5(a) is a side view of the balancer-attached slider ASSY 40, and FIG. 5(b) is a sectional view taken along line B-B in FIG. 5(a).
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 40 a in which a slider 40 d is attached to a high-density balancer 40 f, and a low-density part 40 b attached to the balancer-attached slider 40 a. The balancer-attached slider 40 a rotates in a space filled with oil, and thus reduction in an oil scattering loss can be achieved by attaching the low-density part 40 b to the balancer-attached slider 40 a.
As illustrated in FIGS. 5(a) and 5(b), the low-density part 40 b is attached to the balancer-attached slider ASSY 40 to cover the high-density balancer 40 f. The balancer-attached slider 40 a is provided with an oil drain gap 40 c having a dimension of about 0.5 mm to 3 mm for draining oil leaking from a lower part of the orbiting bearing 21. When provided near a lower end of the orbiting bearing 21, the oil drain gap 40 c allows efficient drain of the oil through a shortest flow path. An eccentric slider fitting hole 40 e for fitting with the eccentric slider shaft portion 14 a is provided in a central part of the balancer-attached slider ASSY 40.
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 40 a 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 40 a, which is, however, not the case with the present Embodiment 2.

Embodiment 3

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.
FIG. 7 is a vertical sectional view of the scroll compressor 100 according to Embodiment 3 of the present invention.
In the present Embodiment 3, as illustrated in FIG. 7, the second balancer 13 includes a high-density part 52 and a low-density part 51 having a density lower than that of the high-density part 52.
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.
FIGS. 8(a) and 8(b) are each a diagram illustrating a method of attaching, to the rotor 12, the second balancer 13 of the scroll compressor 100 according to Embodiment 3 of the present invention. FIG. 8(a) is a plan view of the second balancer 13, and FIG. 8(b) is a side view of the second balancer 13.
A high-density part fastening hole 52 a is formed in the high-density part 52 of the second balancer 13, and a low-density part fastening hole 51 a 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 52 a and the low-density part fastening hole 51 a 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.
FIG. 9 is an enlarged view of the vicinity of the second balancer 13 of the scroll compressor 100 according to Embodiment 3 of the present invention.
As illustrated in FIG. 9, the second balancer 13 including the high-density part 52 and the low-density part 51 may be provided separately from the rotor 12 at a position closer to the sub bearing 16 than the rotor 12. With this configuration, the centrifugal force of the orbiting scroll 5 can be compensated even when the first balancer 27 and the second balancer 13 are downsized. When positioned at a lower position, the second balancer 13 is likely to be immersed into oil. Since the second balancer 13 is solid and has an outline in a cylinder shape, however, no oil scattering nor increase in vibration is caused unlike a case in which only a second balancer in a semi-cylinder shape is provided.

Embodiment 4

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.
FIG. 10 is a vertical sectional view of the scroll compressor 100 according to Embodiment 4 of the present invention. In the present Embodiment 4, as illustrated in FIG. 10, the first balancer 27 is provided below the main bearing 19. Embodiment 4 differs in the position of the first balancer 27 from Embodiment 1 in which the first balancer 27 is provided above the main bearing 19 as illustrated in FIG. 1. However, the same effect as that of Embodiment 1 is obtained with this position in the present Embodiment 4.

REFERENCE SIGNS LIST

1 discharge pipe 2 first fastening member 3 second fastening member 4 fixed scroll 4 a spiral unit (fixed scroll) 5 orbiting scroll 5 a spiral unit (orbiting scroll) 6 frame 6 a space in the frame 7 suction pipe 8 oil discharge pipe 9 low-density part (first balancer) 9 a shaft hole 9 b high-density part housing hole 9 c low-density main part 9 d cover part 9 e low-density part fastening hole 10 high-density part 10 a high-density part fastening hole 11 stator 12 rotor 13 second balancer 14 main shaft 14 a eccentric slider shaft portion 14 b pump shaft portion 14 c 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 40 a balancer-attached slider 40 b low-density part 40 c oil drain gap 40 d slider 40 e eccentric slider fitting hole 40 f 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) 52 a high-density part fastening hole 100 scroll compressor

Claims

1. A scroll compressor comprising:

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 having an outline in a cylinder shape, and including 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,

the low-density part covering an outer peripheral surface of the high-density part.

2. The scroll compressor of claim 1, wherein

the low-density part of the first balancer includes a shaft hole through which the main shaft is provided, a high-density part housing hole for housing the high-density part, and a low-density part fastening hole for fastening with the high-density part,

the high-density part of the first balancer includes a high-density part fastening hole for fastening with the low-density part of the first balancer, and

positions of the high-density part fastening hole of the first balancer and the low-density part fastening hole of the first balancer are aligned, and the high-density part of the first balancer and the low-density part of the first balancer are fastened to each other through a first fastening member with the high-density part of the first balancer being fitted into the high-density part housing hole.

3. The scroll compressor of claim 1, wherein

the first balancer is provided above the electric motor.

4. The scroll compressor of claim 1, further comprising a slider supporting the orbiting scroll, wherein

the first balancer is attached to the slider.

5. The scroll compressor of claim 1, further comprising a second balancer provided below the electric motor unit for compensating unbalance of the orbiting scroll with respect to the rotation center of the main shaft, wherein

the second 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.

6. The scroll compressor of claim 5, further comprising a sub bearing supporting a lower part of the main shaft, wherein

the second balancer is provided at a position closer to the sub bearing than the electric motor unit.

7. The scroll compressor of claim 5, wherein

the electric motor unit includes a rotor and a stator,

the low-density part of the second balancer is provided with a low-density part fastening hole for fastening with the rotor,

the high-density part of the second balancer is provided with a high-density part fastening hole for fastening with the rotor, and

the high-density part of the second balancer and the low-density part of the second balancer are fastened to the rotor through a second fastening member.

8. A method of manufacturing the scroll compressor of claim 2, comprising assembling the first balancer by

aligning the positions of the high-density part fastening hole of the first balancer and the low-density part fastening hole of the first balancer,

fitting the high-density part of the first balancer into the high-density part housing hole, and

fastening the high-density part of the first balancer and the low-density part of the first balancer through the first fastening member.

9. A method of manufacturing the scroll compressor of claim 7, comprising

attaching the second balancer to the rotor by fastening the high-density part of the second balancer and the low-density part of the second balancer to the rotor through the second fastening member.

10. The scroll compressor of claim 1, wherein

the low-density part comprises a resin material.

11. The scroll compressor of claim 4, wherein

the slider includes an oil drain gap for draining oil.

12. The scroll compressor of claim 11, further comprising an orbiting bearing provided opposite to the compression chamber with reference to the orbiting scroll, and supported to orbit freely by an eccentric slider shaft portion installed on an upper part of the main shaft,

wherein the oil drain gap is provided below a lower end of the orbiting bearing.

13. The scroll compressor of claim 12, wherein

the orbiting bearing comprises a parallel sliding bearing, and

the slider is arranged such that a position in a height direction of an action central point of centrifugal force of the entire slider is set to be equal to a position in a height direction of a center of the orbiting bearing.