Scroll compressor

Abstract

This scroll compressor is provided with: a sealed container; a compression mechanism unit that is provided in the sealed container and compresses a refrigerant; an electric mechanism unit that drives the compression mechanism unit; and a rotary shaft that connects the compression mechanism unit and the electric mechanism unit, and transmits the rotational force of the electric mechanism unit to the compression mechanism unit. The compression mechanism unit is provided with: an orbiting scroll that has an orbiting base plate, an upper orbiting spiral body formed on an upper surface of the orbiting base plate, and a lower orbiting spiral body formed on a lower surface of the orbiting base plate; an upper fixed scroll that is disposed over the orbiting scroll, and has an upper fixed base plate and an upper fixed spiral body which is formed on a lower surface of the upper fixed base plate and combined with the upper orbiting spiral body of the orbiting base plate; and a lower fixed scroll that is disposed under the orbiting scroll, and has a lower fixed base plate and a lower fixed spiral body which is formed on an upper surface of the lower fixed base plate and combined with the lower orbiting spiral body of the orbiting base plate. In the orbiting scroll, the radial center of gravity, which is the radial position of the center of gravity of the orbiting scroll, coincides with the center of the orbiting base plate when viewed in the axial direction of the rotational axis.

Description

Scroll Compressor

[0001] The present disclosure relates to a scroll compressor that is mainly mounted in a refrigerator, an air conditioner, a water heater, or the like.

[0002] Conventionally, for example, a vertical scroll compressor has a configuration in which a compression mechanism is disposed in an upper portion of a container, a driving electric mechanism is disposed in a lower portion of the container, and the compression mechanism and the electric mechanism are connected by a rotating shaft. An example of this type of scroll compressor is the scroll compressor disclosed in Patent Document 1. The scroll compressor of Patent Document 1 is a multi-stage scroll compressor in which the compression mechanism has two compression chambers in the vertical direction, which is the axial direction of the rotating shaft.

[0003] The compression mechanism of the scroll compressor disclosed in Patent Document 1 includes an oscillating scroll having a spiral body formed on both sides of a swinging base plate, and two fixed scrolls facing the spiral body. The compression mechanism of the scroll compressor disclosed in Patent Document 1 includes an upper compression chamber having a spiral body and one of two fixed scrolls provided on one side of the swinging base plate of the oscillating scroll, and a lower compression chamber having a spiral body and the other of the two fixed scrolls provided on the other side of the swinging base plate. The scroll compressor disclosed in Patent Document 1 compresses refrigerant in the upper and lower compression chambers by causing the swinging scroll to swing when a rotating shaft rotates.

[0004] Japanese Patent Application Publication No. 10-110690

[0005] The scroll compressor of Patent Document 1 is a multi-stage compressor having a scroll on both sides of the oscillating base plate of the oscillating scroll, and there is a problem in that the compressor becomes unbalanced in the multi-stage compressor, resulting in increased vibration and noise.

[0006] The present disclosure is intended to solve the above-mentioned problems, and aims to provide a scroll compressor that can suppress an increase in vibration and noise in a multi-stage compressor having a scroll body on both sides of the oscillating base plate of the oscillating scroll.

[0007] The scroll compressor according to the present disclosure includes a sealed container, a compression mechanism provided in the sealed container and configured to compress a refrigerant, an electric mechanism for driving the compression mechanism, and a rotary shaft connecting the compression mechanism and the electric mechanism and transmitting the rotational force of the electric mechanism to the compression mechanism. The compression mechanism includes a swinging scroll having a swinging base plate, an upper swinging scroll formed on an upper surface of the swinging base plate, and a lower swinging scroll formed on a lower surface of the swinging base plate, and a rotary shaft disposed above the swinging scroll and configured to have an upper fixed base plate and an upper fixed The rotary scroll is provided with an upper fixed scroll formed on the lower surface of the base plate and having an upper fixed scroll body combined with the upper oscillating scroll body of the oscillating base plate, and a lower fixed scroll arranged below the oscillating scroll and having a lower fixed base plate and a lower fixed scroll body formed on the upper surface of the lower fixed base plate and combined with the lower oscillating scroll body of the oscillating base plate, and the radial center of gravity of the oscillating scroll, which is the radial position of the center of gravity of the oscillating scroll, coincides with the center of the oscillating base plate when viewed in the axial direction of the rotation shaft.

[0008] The scroll compressor according to the present disclosure is a multi-stage compressor having a volute body on both the upper and lower surfaces of the oscillating scroll base plate. The radial center of gravity of the oscillating scroll coincides with the center of the oscillating scroll base plate when viewed in the axial direction of the rotation shaft. This allows the scroll compressor to maintain proper balance and suppress increases in vibration and noise due to poor balance.

[0009] 1 is a schematic longitudinal sectional view illustrating the overall structure of a scroll compressor according to a first embodiment. FIG. 1 is an enlarged schematic longitudinal sectional view of the compression mechanism of FIG. 1. FIG. 2 is a view of the orbiting scroll of the scroll compressor according to the first embodiment as viewed from above. FIG. 3 is a view of the orbiting scroll of the scroll compressor according to the first embodiment as viewed from below. FIG. 4 is a schematic sectional view of the compression mechanism of the scroll compressor according to the second embodiment as viewed from the A-A portion of FIG. 1. FIG. 5 is a schematic sectional view of the compression mechanism of the scroll compressor according to the second embodiment as viewed from the B-B portion of FIG. 1. FIG. 6 is an enlarged schematic longitudinal sectional view of the compression mechanism of the scroll compressor according to the third embodiment. FIG. 7 is a schematic sectional view of the compression mechanism of the scroll compressor according to the fourth embodiment. FIG. 8 is an enlarged schematic longitudinal sectional view of the compression mechanism of the scroll compressor according to the fifth embodiment. FIG. 9 is an explanatory diagram of the positions of the centers of gravity of the upper and lower orbiting scrolls in the scroll compressor according to the sixth embodiment. FIG. 10 is a partial enlarged view of FIG. 11. FIG. 12 is an enlarged schematic longitudinal sectional view of the compression mechanism of the scroll compressor according to the seventh embodiment. FIG. 13 is an enlarged schematic longitudinal sectional view of the central portion of the orbiting scroll of the scroll compressor according to the eighth embodiment as viewed from below. FIG. 14 is an enlarged schematic sectional view of the central portion of the orbiting scroll of the scroll compressor according to the ninth embodiment as viewed from below.

[0010] Embodiment 1. Figure 1 is a schematic vertical cross-sectional view illustrating the overall structure of a scroll compressor 100 according to Embodiment 1. Figure 2 is an enlarged schematic vertical cross-sectional view of the compression mechanism 10 of Figure 1. The scroll compressor 100 according to Embodiment 1 includes a compression mechanism 10, an electric mechanism 20 that drives the compression mechanism 10, and a rotating shaft 4 that connects the compression mechanism 10 and the electric mechanism 20 and transmits the rotational force of the electric mechanism 20 to the compression mechanism 10. The scroll compressor 100 includes the compression mechanism 10, the electric mechanism 20, and the rotating shaft 4 inside a sealed container 50 that forms an outer shell. In the following description, the direction in which the rotating shaft 4 extends is referred to as the axial direction, and the direction perpendicular to the axial direction is referred to as the radial direction.

[0011] The scroll compressor 100 is applied to refrigeration cycle devices such as air conditioners and refrigerators, and is connected by refrigerant piping to a heat exchanger that functions as a condenser or an evaporator and an expansion device, and has the function of compressing the refrigerant to produce a high-temperature, high-pressure gas refrigerant.

[0012] A suction pipe 51 for drawing in the refrigerant and a discharge pipe 52 for discharging the refrigerant are connected to the sealed container 50. The suction pipe 51 is connected to the side surface of the sealed container 50, and the discharge pipe 52 is connected to the top surface of the sealed container 50.

[0013] The compression mechanism 10 has a function of compressing the refrigerant drawn in through the suction pipe 51 and discharging the compressed refrigerant into a high-pressure space 94 in the sealed container 50. The compression mechanism 10 includes an upper fixed scroll 1, a lower fixed scroll 2, and an orbiting scroll 3. The compression mechanism 10 is driven by a rotating shaft 4. The driving force of the rotating shaft 4 is transmitted to the orbiting scroll 3, thereby driving the compression mechanism 10. The rotating shaft 4 is supported by an upper bearing 12 provided at the center of the lower fixed scroll 2 and a lower bearing 13 provided on the subframe 7.

[0014] The compression mechanism 10 has a configuration in which an upper fixed scroll 1 is arranged above the orbiting scroll 3, and a lower fixed scroll 2 is arranged below the orbiting scroll 3. The compression mechanism 10 has a configuration in which the orbiting scroll 3 is arranged between the upper fixed scroll 1 and the lower fixed scroll 2.

[0015] The upper fixed scroll 1 includes an upper fixed base plate 1 a and an upper fixed spiral body 1 c, which is a spiral protrusion formed on a lower surface 1 b of the upper fixed base plate 1 a. The lower fixed scroll 2 includes a lower fixed base plate 2 a and a lower fixed spiral body 2 c, which is a spiral protrusion formed on an upper surface 2 b of the lower fixed base plate 2 a. The upper fixed scroll 1 is fixed to a sealed container 50.

[0016] The orbiting scroll 3 includes an oscillating base plate 3a, an upper oscillating spiral body 3ca which is a spiral protrusion formed on an upper surface 3ba of the oscillating base plate 3a, and a lower oscillating spiral body 3cb which is a spiral protrusion formed on a lower surface 3bb. The upper fixed spiral body 1c and the upper oscillating spiral body 3ca have symmetrical spiral shapes that are out of phase with each other. The orbiting scroll 3 is arranged in a sealed container 50 with the upper fixed scroll 1 and the lower fixed scroll 2 combined so that the spiral bodies mesh with each other.

[0017] An upper compression chamber 71 is formed between the upper fixed scroll 1c and the upper oscillating scroll 3ca. The upper compression chamber 71 moves from the radially outer side to the radially inner side as the upper oscillating scroll 3ca oscillates in accordance with the rotation of the rotary shaft 4. The upper compression chamber 71 is configured so that its volume decreases as it moves from the radially outer side to the radially inner side.

[0018] Similarly, the lower fixed scroll 2c and the lower oscillating scroll 3cb have symmetrical spiral shapes in opposite phases. A lower compression chamber 72 is formed between the lower fixed scroll 2c and the lower oscillating scroll 3cb. The lower compression chamber 72 moves from the radially outer side to the radially inner side as the lower oscillating scroll 3cb oscillates with the rotation of the rotary shaft 4. The volume of the lower compression chamber 72 decreases as it moves from the radially outer side to the radially inner side.

[0019] Hereinafter, the upper fixed scroll 1c and the lower fixed scroll 2c may be collectively referred to as the scrolls of the fixed scroll, and the upper oscillating scroll 3ca and the lower oscillating scroll 3cb may be collectively referred to as the scrolls of the oscillating scroll 3.

[0020] The scroll compressor 100 is a multi-stage compressor in which the compression mechanism section 10 has a plurality of compression mechanisms, and the compression mechanism section 10 has a low-stage compression mechanism 92 and a high-stage compression mechanism 93. The low-stage compression mechanism 92 includes a lower fixed scroll 2 and an orbiting scroll 3, and compresses the refrigerant drawn in from the suction pipe 51 in a lower compression chamber 72. The high-stage compression mechanism 93 includes an upper fixed scroll 1 and an orbiting scroll 3, and draws in the refrigerant compressed in the low-stage compression mechanism 92 and compresses it in an upper compression chamber 71.

[0021] The upper fixed scroll 1 and the lower fixed scroll 2 are fixed to the sealed container 50. Alternatively, the lower fixed scroll 2 may be fixed to the sealed container 50, and the upper fixed scroll 1 may be fixed to the lower fixed scroll 2, thereby fixing the scrolls to the sealed container 50. In a structure in which the upper fixed scroll 1 is fixed to the lower fixed scroll 2 and thereby fixed to the sealed container 50, the lower fixed scroll 2 has a cylindrical wall portion that protrudes upward on its outer periphery. The upper fixed scroll 1 is fixed to the lower fixed scroll 2 by being fastened to the wall portion with bolts or the like.

[0022] The lower fixed scroll 2 is formed with a first inlet passage 25 that guides refrigerant drawn from the suction pipe 51 into the compression mechanism 10. The first inlet passage 25 penetrates the lower fixed scroll 2 from the lower surface of the lower fixed scroll 2 toward the lower fixed scroll 2c. The lower fixed scroll 2 is also formed with a second inlet passage 26 that guides refrigerant compressed in the low-stage compression mechanism 92 to the high-stage compression mechanism 93. The second inlet passage 26 penetrates the lower fixed base plate 2a so that its upstream end opens to the lower compression chamber 72 and its downstream end opens to the upper compression chamber 71. In the illustrated example, the downstream end of the second inlet passage 26 is open, but the scroll compressor 100 may be configured to include a discharge valve that opens and closes the downstream end of the second inlet passage 26. If the scroll compressor 100 includes a discharge valve, a downwardly recessed recess may be formed in the upper surface of the lower fixed scroll 2, and the discharge valve may be installed in the recess.

[0023] An upper fixed base plate 1a of the upper fixed scroll 1 is provided with a discharge port 1d at the center thereof, and an upper discharge valve 1e is provided at the outlet of the discharge port 1d.

[0024] An Oldham ring 5 is disposed between the lower fixed scroll 2 and the orbiting scroll 3 to prevent rotation of the orbiting scroll 3 during orbital motion. The Oldham ring 5 is disposed above the lower fixed scroll 2 and between the lower fixed scroll 2 and the orbiting scroll 3. Although not shown in detail in FIGS. 1 and 2 , the Oldham ring 5 has an annular ring portion and a pair of key portions 5 a formed protruding from the upper and lower surfaces of the ring portion. The pair of upper and lower key portions 5 a of the Oldham ring 5 are fitted into a groove 3 d formed in the lower surface 3 bb of the orbiting base plate 3 a of the orbiting scroll 3 and a groove 2 d formed in the upper surface of the lower fixed scroll 2. The pair of upper and lower key portions 5 a of the Oldham ring 5 are fitted into the groove 3 d of the orbiting scroll 3 and the groove 2 d of the lower fixed scroll 2, thereby preventing rotation of the orbiting scroll 3 during orbital motion.

[0025] The electric mechanism 20 supplies rotational driving force to the rotating shaft 4 and includes a motor stator 21 and a motor rotor 22 as shown in FIG. 1 . The motor stator 21 is fixed to the inner circumferential surface of the sealed container 50 by shrink fitting or the like. The motor stator 21 is connected to a glass terminal (not shown) installed in the sealed container 50 by a lead wire (not shown) to obtain electric power from the outside. The motor rotor 22 is fixed to the rotating shaft 4 by shrink fitting or the like. The motor rotor 22 rotates when current is applied to the motor stator 21, thereby rotating the rotating shaft 4. A first balance weight 23 and a second balance weight 24 are fixed to the motor rotor 22 to balance the entire rotating system of the scroll compressor 100.

[0026] The rotating shaft 4 is composed of a lower shaft portion 4a located at the bottom and an eccentric shaft portion 4b located at the top. The lower shaft portion 4a is fixed to the motor rotor 22. The eccentric shaft portion 4b is fitted into a swing bearing 11 provided on the orbiting scroll 3. The central axis of the eccentric shaft portion 4b is eccentric with respect to the central axis of the lower shaft portion 4a of the rotating shaft 4. The eccentric shaft portion 4b is inserted into the swing bearing 11 provided on the orbiting scroll 3 and connected to the orbiting base plate 3a without passing through the orbiting base plate 3a of the orbiting scroll 3. The eccentric shaft portion 4b is configured to cause the orbiting scroll 3 to swing when the rotating shaft 4 rotates.

[0027] The lower shaft portion 4a is rotatably inserted into an upper bearing portion 12 disposed in the center of the lower fixed scroll 2 and a lower bearing portion 13 disposed in the center of a subframe 7 provided in the lower part of the sealed container 50. The upper bearing portion 12 and the lower bearing portion 13 are made of a bearing material used for sliding bearings, such as a copper-lead alloy, and are fixed to the lower fixed scroll 2 and the subframe 7 by press-fitting or the like.

[0028] The lower end of the lower shaft portion 4a of the rotating shaft 4 is connected to an oil pump 6, and the oil pump 6 is configured to be immersed in refrigeration oil stored in an oil reservoir 9 at the bottom of the sealed container 50. An oil supply path (not shown) is formed inside the rotating shaft 4, opening at the lower end of the lower shaft portion 4a and extending to the eccentric shaft portion 4b, so that refrigeration oil in the oil reservoir 9 can be supplied to each sliding portion. The rotating shaft 4 slides via an oil film of refrigeration oil.

[0029] As shown in Figure 1, the space inside the sealed container 50 is defined as follows: Within the internal space of the sealed container 50, the space below the lower fixed scroll 2 is referred to as a low-pressure space 91. Within the internal space of the sealed container 50, the space above the upper fixed scroll 1 is referred to as a high-pressure space 94.

[0030] The upper fixed scroll 1 separates the space within the high-stage compression mechanism 93 from the high-pressure space 94. The swinging base plate 3a of the swinging scroll 3 separates the high-stage compression mechanism 93 from the low-stage compression mechanism 92. The lower fixed scroll 2 separates the space within the low-stage compression mechanism 92 from the low-pressure space 91. The high-stage compression mechanism 93 and the low-stage compression mechanism 92 are separated by the swinging base plate 3a and are airtightly separated from the low-pressure space 91 and the high-pressure space 94 except for the first introduction path 25.

[0031] The pressure relationship among the spaces within the sealed container 50 is as follows: high-pressure space 94 > high-stage compression mechanism 93 > low-stage compression mechanism 92 > low-pressure space 91. Therefore, the swinging base plate 3a of the swinging scroll 3 swings while being pressed downward by the pressure difference between the pressure inside the high-stage compression mechanism 93 and the pressure inside the low-stage compression mechanism 92. Because the swinging scroll 3 swings while being pressed downward, it swings stably without axial displacement even though it is not fixed in the axial direction. By being pressed downward by the pressure difference, the swinging scroll 3 seals gaps between the tip surfaces of the lower swinging scroll 3cb and the lower fixed scroll 2c and the opposing surfaces 2b and 3bb, making the lower compression chamber 72 airtight and suppressing refrigerant leakage from the lower compression chamber 72. Alternatively, by sealing the gap between the oscillating base plate 3a and the thrust surface 2aa of the lower fixed scroll 2, the high-stage compression mechanism 93 and the low-stage compression mechanism 92 can be separated, thereby preventing refrigerant leakage.

[0032] However, conventional multi-stage scroll compressors are poorly balanced, which can cause vibration and noise.

[0033] In the scroll compressor 100 of the first embodiment, the radial center of gravity G1 of the orbiting scroll 3 (see FIG. 3 described later) coincides with the center O of the orbiting base plate 3a. The radial center of gravity G1 of the orbiting scroll 3 is the radial center of gravity position of the center of gravity G of the entire orbiting scroll 3. The center O of the orbiting base plate 3a is the center of the orbiting base plate 3a when the orbiting base plate 3a is viewed in the axial direction (hereinafter, abbreviated as the center O of the orbiting base plate 3a). In the scroll compressor 100 of the first embodiment, the radial center of gravity G1 of the orbiting scroll 3 coincides with the center O of the orbiting base plate 3a. This allows the scroll compressor 100 to maintain good balance and suppress various problems caused by poor balance. Note that in this specification, "coincidence" is not limited to strict coincidence, but also includes a case where good balance can be maintained and the two can be recognized as substantially coinciding.

[0034] Here, the scroll compressor 100 has the following specific configuration in which the radial center of gravity G1 of the orbiting scroll 3 coincides with the center O of the orbiting base plate 3a.

[0035] Fig. 3 is a view of the orbiting scroll 3 of the scroll compressor 100 according to embodiment 1 as seen from above. Fig. 4 is a view of the orbiting scroll 3 of the scroll compressor 100 according to embodiment 1 as seen from below.

[0036] First, the shapes of the upper oscillating spiral 3ca and the lower oscillating spiral 3cb will be described. The upper oscillating spiral 3ca and the lower oscillating spiral 3cb have shapes that follow an involute curve, as shown in Figures 3 and 4. The upper oscillating spiral 3ca is disposed on the oscillating bed plate 3a with the base circle center 3da of the involute offset from the center O of the oscillating bed plate 3a. The lower oscillating spiral 3cb is disposed on the oscillating bed plate 3a with the base circle center 3db of the involute offset from the center O of the oscillating bed plate 3a.

[0037] The upper and lower oscillating spirals 3ca and 3cb have the same spiral shape but are positioned differently relative to the oscillating base plate 3a. The upper and lower oscillating spirals 3ca and 3cb are arranged point-symmetrically with respect to the center O of the oscillating base plate 3a.

[0038] The upper oscillating spiral body 3ca and the lower oscillating spiral body 3cb are arranged point-symmetrically with respect to the center O of the oscillating base plate 3a, so that the radial center of gravity G1 of the oscillating scroll 3 coincides with the center O of the oscillating base plate 3a.

[0039] The upper oscillating scroll 3ca and the lower oscillating scroll 3cb are point-symmetric with respect to the center O of the oscillating base plate 3a. In other words, the base circle center 3da of the involute of the upper oscillating scroll 3ca and the base circle center 3db of the lower oscillating scroll 3cb are located at positions point-symmetric with respect to the center O of the oscillating base plate 3a when viewed in the axial direction of the oscillating scroll 3a. As a result, the radial center of gravity G1 of the oscillating scroll 3 coincides with the center O of the oscillating base plate 3a even when the center of gravity positions of the upper oscillating scroll 3ca and the lower oscillating scroll 3cb are misaligned.

[0040] Furthermore, when the base circle center 3da of the involute of the upper oscillating scroll 3ca and the base circle center 3db of the involute of the lower oscillating scroll 3cb coincide with the center O of the oscillating base plate 3a, the radial center of gravity G1 of the oscillating scroll 3 naturally coincides with the center O of the oscillating base plate 3a. Note that D1 and D2 in Figures 3 and 4 will be explained in the third embodiment described later.

[0041] 1 and 2 , the flow of refrigerant in the scroll compressor 100 according to the first embodiment will be described. When the electric mechanism 20 is driven, refrigerant flows from the refrigeration cycle circuit connected to the scroll compressor 100 through the suction pipe 51 into the low-pressure space 91 in the sealed container 50. The refrigerant that has flowed into the low-pressure space 91 passes through the first introduction path 25 and flows into the compression mechanism 10. The refrigerant that flows in from the suction pipe 51 is a refrigerant at a relatively low pressure in the refrigeration cycle circuit.

[0042] The refrigerant that has flowed into the compression mechanism 10 flows into the lower compression chamber 72 of the low-stage compression mechanism 92. The refrigerant that has flowed into the lower compression chamber 72 is compressed by the lower fixed scroll 2c and the lower oscillating scroll 3cb and is discharged from the lower compression chamber 72 through the second inlet path 26. The refrigerant that has been discharged from the lower compression chamber 72 flows into the upper compression chamber 71 of the high-stage compression mechanism 93. The refrigerant that has flowed into the upper compression chamber 71 is further compressed by the upper fixed scroll 1c and the upper oscillating scroll 3ca to become high-pressure refrigerant and is discharged from the discharge port 1d through the upper discharge valve 1e into the high-pressure space 94.

[0043] (Effects of the Scroll Compressor 100 of the First Embodiment) In the scroll compressor 100, the radial center of gravity G1 of the orbiting scroll 3 coincides with the center O of the orbiting base plate 3 a. Therefore, the scroll compressor 100 can properly maintain the balance of the orbiting scroll 3, and can suppress increases in vibration and noise due to deterioration of the balance.

[0044] In a scroll compressor, if the orbiting scroll is out of balance, the load on the pawls of the Oldham ring, which prevents the orbiting scroll from rotating, increases, making it more likely that problems such as breakage and wear of the Oldham ring will occur.

[0045] In contrast, in the scroll compressor 100, the radial center of gravity of the entire oscillating scroll 3 coincides with the center O of the oscillating base plate 3a, so that the balance of the oscillating scroll 3 can be maintained well and an increase in the load on the key portion 5a of the Oldham ring 5 can be suppressed.

[0046] Furthermore, if the balance of the orbiting scroll of the scroll compressor is poor, the airtightness of the compression chamber may be impaired, resulting in a decrease in performance.

[0047] In contrast, the scroll compressor 100 can maintain a good balance of the orbiting scroll 3, so that the airtightness of the upper compression chamber 71 and the lower compression chamber 72 can be maintained and performance degradation can be suppressed.

[0048] The scroll compressor 100 can have the following configuration in which the radial center of gravity G1 of the oscillating scroll 3 coincides with the center O of the oscillating bed plate 3a. The upper oscillating scroll 3ca and the lower oscillating scroll 3cb are provided on the oscillating bed plate 3a in point symmetry with respect to the center O of the oscillating bed plate 3a. The upper oscillating scroll 3ca and the lower oscillating scroll 3cb each have a shape following an involute curve. The base circle center 3da of the involute of the upper oscillating scroll 3ca and the base circle center 3db of the involute of the lower oscillating scroll 3cb are offset from the center O of the oscillating bed plate 3a. The upper oscillating scroll 3ca and the lower oscillating scroll 3cb are provided on the oscillating bed plate 3a in point symmetry with respect to the center O of the oscillating bed plate 3a.

[0049] Embodiment 2. Figure 5 is a schematic cross-sectional view of the compression mechanism 10 of the scroll compressor 100 according to embodiment 2, taken along line A-A in Figure 1. Figure 6 is a schematic cross-sectional view of the compression mechanism 10 of the scroll compressor 100 according to embodiment 2, taken along line B-B in Figure 1. The following description will focus on differences between embodiment 2 and embodiment 1, and configurations not described in embodiment 2 are similar to those in embodiment 1.

[0050] In the scroll compressor 100 of the first embodiment, the upper fixed scroll body 1c and the upper oscillating scroll body 3ca are symmetrical. In contrast, in the scroll compressor 100 of the second embodiment, the upper fixed scroll body 1c and the upper oscillating scroll body 3ca are asymmetrical, as shown in FIG. 5 . The upper fixed scroll body 1c has a shape in which the winding end is elongated more than the upper oscillating scroll body 3ca. Thus, in the scroll compressor 100, the upper fixed scroll body 1c and the upper oscillating scroll body 3ca are not necessarily symmetrical but may be asymmetrical. Note that FIG. 5 differs from FIG. 1 in the number of turns of the upper fixed scroll body 1c and the upper oscillating scroll body 3ca. Please refer to FIG. 5 as a reference diagram illustrating the asymmetrical shape of the upper fixed scroll body 1c and the upper oscillating scroll body 3ca.

[0051] In the scroll compressor 100 of the first embodiment, the lower fixed scroll body 2c and the lower oscillating scroll body 3cb are symmetrical. In contrast, in the scroll compressor 100 of the second embodiment, the lower fixed scroll body 2c and the lower oscillating scroll body 3cb are asymmetrical, as shown in FIG. 6 . The lower fixed scroll body 2c has a shape in which the end of the winding is more elongated than the lower oscillating scroll body 3cb. In this manner, the scroll compressor 100 may have asymmetrical shapes of the lower fixed scroll body 2c and the lower oscillating scroll body 3cb. Note that FIG. 6 differs from FIG. 1 in the number of windings of the lower fixed scroll body 2c and the lower oscillating scroll body 3cb. Please refer to FIG. 6 as a reference diagram illustrating the asymmetrical shapes of the lower fixed scroll body 2c and the lower oscillating scroll body 3cb.

[0052] In the scroll compressor 100 of the second embodiment, similarly to the scroll compressor 100 of the first embodiment, the base circle center 3da of the involute of the upper oscillating scroll 3ca and the base circle center 3db of the involute of the lower oscillating scroll 3cb are arranged to be offset from the center O of the oscillating base plate 3a. This allows the upper oscillating scroll 3ca and the lower oscillating scroll 3cb to be arranged more efficiently spread across the entire surface of the oscillating base plate 3a, compared to a configuration in which the base circle centers 3da and 3db coincide with the center O of the oscillating base plate 3a.

[0053] In the scroll compressor 100, the upper oscillating scroll 3ca and the lower oscillating scroll 3cb can be efficiently spread across the entire surface of the oscillating base plate 3a, allowing the involute of the scroll to be extended compared to a configuration in which the base circle center 3da of the upper oscillating scroll 3ca and the base circle center 3db of the lower oscillating scroll 3cb coincide with the center O of the oscillating base plate 3a. Because the scroll compressor 100 can extend the involute of the scroll, a larger scroll can be formed for the same base plate size, making it easier to form an asymmetrical shape between the upper oscillating scroll 3ca and the upper fixed scroll 1c facing the upper oscillating scroll 3ca. An asymmetrical scroll is formed by elongating either the fixed scroll or the oscillating scroll more than a symmetrical scroll. An asymmetrical scroll can have a larger displacement than a symmetrical scroll.

[0054] Similarly, in the scroll compressor 100, the upper oscillating scroll 3ca and the lower oscillating scroll 3cb can be efficiently spread across the entire surface of the oscillating base plate 3a, which allows the lower oscillating scroll 3cb and the lower fixed scroll 2c facing the lower oscillating scroll 3cb to have an asymmetrical shape. In other words, the scroll compressor 100 can easily make the scrolls of the fixed scroll and the scrolls of the oscillating scroll 3 asymmetrical while maintaining a relationship in which the radial center of gravity G1 of the oscillating scroll 3 as a whole coincides with the center O of the oscillating base plate 3a.

[0055] (Effects of the Scroll Compressor 100 of the Second Embodiment) The scroll compressor 100 of the second embodiment has an asymmetrical configuration between the scroll body of the fixed scroll and the scroll body of the orbiting scroll 3, and therefore has the same effects as those of the first embodiment. That is, the scroll compressor 100 of the second embodiment has the effect of suppressing an increase in vibration and noise due to poor balance, and suppressing an increase in the load applied to the key portion 5 a of the Oldham ring 5.

[0056] Furthermore, in the scroll compressor 100 of embodiment 2, the spiral body of the fixed scroll and the spiral body of the oscillating scroll 3 have asymmetric shapes, so that the displacement volume in each of the upper compression chamber 71 and the lower compression chamber 72 can be increased, thereby increasing the compressor capacity.

[0057] Embodiment 3. Embodiment 3 relates to the axial height of the upper oscillating scroll 3ca and the lower oscillating scroll 3cb. The following description will focus on the differences between Embodiment 3 and Embodiments 1 and 2, and the configuration not described in Embodiment 3 is the same as that of Embodiments 1 and 2.

[0058] 7 is an enlarged schematic vertical cross-sectional view of the compression mechanism 10 of the scroll compressor 100 according to Embodiment 3. In the scroll compressor 100 of Embodiment 3, the height H1 of the upper oscillating scroll 3ca is lower than the height H2 of the lower oscillating scroll 3cb. The plate thickness of the upper oscillating scroll 3ca and the lower oscillating scroll 3cb is the same.

[0059] Because the refrigerant pressure in the high-stage compression mechanism 93 is higher than the refrigerant pressure in the low-stage compression mechanism 92, the load applied to the base of the upper oscillating volute 3ca is greater than the load applied to the base of the lower oscillating volute 3cb. In the scroll compressor 100, the height H1 of the upper oscillating volute 3ca is lower than the height H2 of the lower oscillating volute 3cb, thereby providing the upper oscillating volute 3ca with greater strength than in a configuration in which H1 is the same as or higher than H2. Furthermore, because the refrigerant flowing into the high-stage compression mechanism 93 is more compressed than the refrigerant flowing into the low-stage compression mechanism 92, the volume of the refrigerant flowing into the high-stage compression mechanism 93 is smaller than the volume of the refrigerant flowing into the low-stage compression mechanism 92 at the same flow rate. This means that the height of the volutes in the high-stage compression mechanism 93 can be reduced without causing any problems.

[0060] In the scroll compressor 100, the upper oscillating volute 3ca is lighter than a configuration in which the height H1 of the upper oscillating volute 3ca is not lowered by the amount corresponding to the height H2. Therefore, the scroll compressor 100 has the following arrangement to balance the upper oscillating volute 3ca and the lower oscillating volute 3cb. The scroll compressor 100 has a configuration in which the base circle center 3da of the upper oscillating volute 3ca is shifted outward by the ratio of H1 to H2 from a position point-symmetrical with the base circle center 3db of the lower oscillating volute 3cb about the center O of the oscillating base plate 3a.

[0061] Specifically, the scroll compressor 100 has a configuration in which the upper oscillating scroll 3ca is disposed at a position that satisfies D1 = (H2 / H1) × D2, where D1 (see FIGS. 3 and 4) is the distance from the center O of the oscillating plate 3a to the base circle center 3da of the upper oscillating scroll 3ca, and D2 (see FIGS. 3 and 4) is the distance from the center O of the oscillating plate 3a to the base circle center 3db of the lower oscillating scroll 3cb.

[0062] (Effects of Scroll Compressor 100 of Embodiment 3) The scroll compressor 100 of Embodiment 3 has the same effects as those of Embodiments 1 and 2, as well as the following effect: In the scroll compressor 100 of Embodiment 3, the height H1 of the upper oscillating scroll 3ca is lower than the height H2 of the lower oscillating scroll 3cb, and therefore the upper oscillating scroll 3ca can be made stronger than in a configuration in which H1 is the same as or higher than H2.

[0063] Embodiment 4. Embodiment 4 relates to the axial height of the upper oscillating scroll 3ca and the lower oscillating scroll 3cb. The following description will focus on the differences between Embodiment 4 and Embodiments 1 and 2, and the configuration not described in Embodiment 4 is the same as that of Embodiments 1 and 2.

[0064] 8 is an enlarged schematic vertical cross-sectional view of the compression mechanism 10 of the scroll compressor 100 according to the fourth embodiment. In the scroll compressor 100 according to the fourth embodiment, the height H1 of the upper oscillating scroll 3ca and the height H2 of the lower oscillating scroll 3cb are the same. In this way, the scroll compressor 100 is not limited to one in which the height H1 of the upper oscillating scroll 3ca and the height H2 of the lower oscillating scroll 3cb are different, and may be the same.

[0065] In the scroll compressor 100, the height H1 of the upper oscillating scroll 3ca is the same as the height H2 of the lower oscillating scroll 3cb, so the center of gravity G of the entire oscillating scroll 3 coincides with the center of gravity G2 of the oscillating base plate 3a of the oscillating scroll 3.

[0066] (Effects of the Scroll Compressor 100 of Embodiment 4) Even when the height H1 of the upper oscillating scroll 3ca and the height H2 of the lower oscillating scroll 3cb are the same, the scroll compressor 100 of Embodiment 4 can achieve the same effects as those of Embodiments 1 and 2. That is, the scroll compressor 100 of Embodiment 4 can achieve the effect of suppressing increases in vibration and noise due to poor balance and of suppressing increases in the load on the key portions 5a of the Oldham ring 5.

[0067] Embodiment 5. Embodiment 5 relates to the thickness of the upper oscillating spiral body 3ca and the lower oscillating spiral body 3cb. The following description will focus on the differences between embodiment 5 and embodiment 4, and the configuration not described in embodiment 5 is the same as embodiment 4.

[0068] 9 is an enlarged schematic vertical cross-sectional view of the compression mechanism 10 of a scroll compressor 100 according to Embodiment 5. In the scroll compressor 100 of Embodiment 5, the thickness T1 of the upper oscillating scroll 3ca is greater than the thickness T2 of the lower oscillating scroll 3cb. As in Embodiment 4, the scroll compressor 100 of Embodiment 5 has the upper oscillating scroll 3ca and the lower oscillating scroll 3cb having the same height.

[0069] In the scroll compressor 100, the pressure of the refrigerant in the high-stage compression mechanism 93 is higher than the pressure of the refrigerant in the low-stage compression mechanism 92. Therefore, in the scroll compressor 100, the load applied to the base of the upper oscillating volute 3ca that constitutes the high-stage compression mechanism 93 is greater than the load applied to the base of the lower oscillating volute 3cb that constitutes the low-stage compression mechanism 92. In the scroll compressor 100, the thickness T1 of the upper oscillating volute 3ca is greater than the thickness T2 of the lower oscillating volute 3cb, so that the upper oscillating volute 3ca can have greater strength than in a configuration in which T1 is the same as or smaller than T2.

[0070] In the scroll compressor 100, the weight of the upper oscillating scroll 3ca is heavier than the lower oscillating scroll 3cb because the thickness T1 of the upper oscillating scroll 3ca is greater than the thickness T2. Therefore, the scroll compressor 100 has the following arrangement to balance the upper oscillating scroll 3ca and the lower oscillating scroll 3cb.

[0071] The scroll compressor 100 has a configuration in which the base circle center 3db of the lower oscillating volute 3cb is positioned further outward from the position point-symmetrical to the base circle center 3da of the upper oscillating volute 3ca, with the center O of the oscillating base plate 3a as the center, by the ratio of T1 to T2.

[0072] Specifically, the scroll compressor 100 has a configuration in which the upper oscillating volute 3ca and the lower oscillating volute 3cb are arranged at positions that satisfy (D1:D2=T2:T1), where D1 is the distance from the center O of the oscillating bed plate 3a to the base circle center 3da of the upper oscillating volute 3ca, and D2 is the distance from the center O of the oscillating bed plate 3a to the base circle center 3db of the lower oscillating volute 3cb, as shown in Figures 3 and 4 .

[0073] Depending on the configuration of the scroll compressor 100, the high-stage compression mechanism 93 may be located on the lower side and the low-stage compression mechanism 92 on the upper side. In this configuration, the thickness T2 of the lower oscillating scroll 3cb that constitutes the high-stage compression mechanism 93 is configured to be larger than the thickness T1 of the upper oscillating scroll 3ca that constitutes the low-stage compression mechanism 92. This allows the scroll compressor 100 to provide strength to the high-stage scroll.

[0074] In short, the scroll compressor 100 of the fifth embodiment has a compression mechanism including the orbiting scroll 3 and the upper fixed scroll 1, and a compression mechanism including the orbiting scroll 3 and the lower fixed scroll 2. One of these two compression mechanisms is a low-stage compression mechanism that compresses refrigerant drawn into the sealed container 50, and the other is a high-stage compression mechanism that draws in and compresses refrigerant compressed by the low-stage compression mechanism. The scroll compressor 100 of the fifth embodiment has a configuration in which, of the upper and lower orbiting scrolls 3ca and 3cb, the thickness of the scrolls constituting the high-stage compression mechanism 93 is greater than the thickness of the scrolls constituting the low-stage compression mechanism 92.

[0075] In a configuration in which the high-stage compression mechanism 93 is located on the lower side and the low-stage compression mechanism 92 is located on the upper side, and the thickness T2 of the lower oscillating volute 3cb is greater than the thickness T1 of the upper oscillating volute 3ca, the scroll compressor 100 has the following configuration: The scroll compressor 100 has a configuration in which the upper oscillating volute 3ca and the lower oscillating volute 3cb are arranged at positions that satisfy (D1:D2=T2:T1), as in the above case.

[0076] (Effects of Scroll Compressor 100 of Embodiment 5) The scroll compressor 100 of Embodiment 5 can achieve the same effects as those of Embodiment 4, as well as the following effect. In the scroll compressor 100 of Embodiment 5, the thickness of the scroll that constitutes the high-stage side compression mechanism 93 is greater than the thickness of the scroll that constitutes the low-stage side compression mechanism 92. Therefore, in the scroll compressor 100 of Embodiment 5, the scroll that constitutes the high-stage side compression mechanism 93 can have greater strength than in a configuration in which the thickness of the scroll that constitutes the high-stage side compression mechanism 93 is the same as or smaller than the thickness of the scroll that constitutes the low-stage side compression mechanism 92.

[0077] Sixth Embodiment The sixth embodiment relates to the number of turns of the involute of the spirals of the upper oscillating spiral body 3ca and the lower oscillating spiral body 3cb, and the length of the involute depending on the number of turns. The following description will focus on the differences between the sixth embodiment and the fourth embodiment, and the configuration not described in the sixth embodiment is the same as the fourth embodiment.

[0078] In the scroll compressor 100 of the sixth embodiment, the number of turns of the involute of the spiral and the length of the involute resulting from the number of turns are different between the upper oscillating scroll 3ca and the lower oscillating scroll 3cb. Note that, in the scroll compressor 100 of the sixth embodiment, the upper oscillating scroll 3ca and the lower oscillating scroll 3cb have the same height and thickness as in the fourth embodiment.

[0079] The upper oscillating volute body 3ca and the lower oscillating volute body 3cb are formed by an involute curve. The basic equation of an involute curve is expressed by the following equation (1) in a coordinate system with the center of the base circle as the center and the involute angle φ as a parameter, where a is the radius of the base circle. Equation (1) is excerpted from "Geometric Theory of Scroll Compressors, Authors: Morishita Etsuo, Sugihara Masahiro, Book Title: Turbomachinery, Vol. 13, No. 4, pp. 209-219, Published: April 10, 1985, by the Turbomachinery Society of Japan."

[0080]

[0081] The length of the involute is expressed by the following equation (2).

[0082]

[0083] where Φ is the involute end involution angle, and N is the number of turns −1 / 4.

[0084] The length l of the involute is expressed by the following equation (3).

[0085]

[0086] where φ ０ is the involute starting involution angle.

[0087] As can be seen from the above equations (3) and (2), the length l of the involute changes depending on the number of turns N. Furthermore, even if the number of turns N is the same, the length l of the involute will be different if φ0 is different. Since an actual spiral body has a tooth thickness, different involute equations exist for the inward surface of the spiral body and the outward surface of the spiral body. For simplicity's sake, the above equation (3) is expressed as the equation of an involute that passes through the center of the tooth.

[0088] In coordinates centered on the center of the base circle, the position of the center of gravity (xG, yG) of the involute curve is expressed by the following equation (4).

[0089]

[0090] The position of the center of gravity (xG, yG) of the involute curve can be transformed into equation (6) using equation (5) below.

[0091]

[0092]

[0093] FIG. 10 is an explanatory diagram of the center of gravity positions of the upper oscillating scroll 3ca and the lower oscillating scroll 3cb in the scroll compressor 100 according to the sixth embodiment. FIG. 11 is a partial enlarged view of FIG. 10. In the above-described embodiment, the dotted circles shown in FIGS. 3 to 6 are referred to as "base circle centers." Specifically, the dotted circles are "base circles," and the centers of the dotted circles are "base circle centers." Therefore, in FIGS. 10 and 11, the center of the dotted circle 3da is referred to as the base circle center 3da1, and the center of the dotted circle 3db is referred to as the base circle center 3db1. As shown in FIGS. 10 and 11, the position of the center of gravity Ga of the involute of the upper oscillating scroll 3ca is represented by (xga, yga) in coordinates centered on the base circle center 3da1 of the upper oscillating scroll 3ca. The position of the center of gravity Gb of the involute of the lower oscillating spiral body 3cb is (xgb, ygb) in coordinates centered on the base circle center 3db1 of the lower oscillating spiral body 3cb.

[0094] Here, the number of turns of the upper oscillating spiral body 3ca is N1, and the number of turns of the lower oscillating spiral body 3cb is N2. The length of the involute of the upper oscillating spiral body 3ca is l1, and the length of the involute of the lower oscillating spiral body 3cb is l2. l1 and l2 can be calculated using the above formula (3).

[0095] Furthermore, if the weight of the upper oscillating scroll 3ca is M1 and the weight of the lower oscillating scroll 3cb is M2, the weight of the involute is proportional to the length of the involute if the height and thickness are the same. Therefore, the ratio of the involute lengths is the ratio of the involute weights, so M1:M2 = l1:l2.

[0096] Here, the center of gravity Ga of the upper oscillating spiral 3ca and the center of gravity Gb of the lower oscillating spiral 3cb are located symmetrically with respect to the center O of the oscillating bed 3a. In other words, the upper oscillating spiral 3ca and the lower oscillating spiral 3cb are arranged on the oscillating bed 3a so that the coordinates (xga, yga) of the center of gravity Ga and the coordinates (xgb, ygb) of the center of gravity Gb are symmetric with respect to the center O of the oscillating bed 3a.

[0097] Furthermore, when the oscillating plate 3a is viewed in the axial direction of the rotation shaft 4, the distance from the center O of the oscillating plate 3a to the center of gravity Ga of the upper oscillating spiral body 3ca is defined as Da, and the distance from the center O of the oscillating plate 3a to the center of gravity Gb of the lower oscillating spiral body 3cb is defined as Db. In this case, the oscillating scroll 3 has a configuration in which the upper oscillating spiral body 3ca and the lower oscillating spiral body 3cb are arranged on the oscillating plate 3a at positions that satisfy Da:Db=M2:M1, that is, so as to satisfy Da:Db=l2:l1.

[0098] The number of turns of the upper oscillating scroll 3ca is N1, and the number of turns of the lower oscillating scroll 3cb is N2. In the oscillating scroll 3, N1 and N2 are the same, and the involute start angle φ ０ Even if the upper oscillating spiral body 3ca and the lower oscillating spiral body 3cb differ in Da:Db=M2:M1, that is, Da:Db=l2:l1, the upper oscillating spiral body 3ca and the lower oscillating spiral body 3cb may be arranged on the oscillating base plate 3a so as to satisfy Da:Db=M2:M1, that is, Da:Db=l2:l1.

[0099] (Effects of Scroll Compressor 100 of Sixth Embodiment) Even when the scroll compressor 100 of the sixth embodiment is configured such that the number of turns and the length of the involute of the upper oscillating scroll 3ca and the lower oscillating scroll 3cb are different from each other, by satisfying Da:Db=l2:l1, it is possible to obtain the same effects as those of the first to fifth embodiments. In other words, the scroll compressor 100 of the sixth embodiment can obtain the effect of suppressing an increase in vibration and noise due to a deterioration in balance, and of suppressing an increase in the load on the key portion 5a of the Oldham ring 5.

[0100] Embodiment 7. Embodiment 7 relates to the height, thickness, number of turns, and involute length of upper oscillating spiral body 3ca and lower oscillating spiral body 3cb. The following description will focus on the differences between embodiment 7 and embodiments 1 to 6, and the configuration not described in embodiment 7 is the same as embodiments 1 to 6.

[0101] 12 is an enlarged schematic vertical cross-sectional view of the compression mechanism 10 of a scroll compressor 100 according to a seventh embodiment. In the scroll compressor 100 of the seventh embodiment, the upper and lower oscillating scrolls 3ca and 3cb are different from each other in terms of height, thickness, number of turns, and involute length. The weight ratio between the upper and lower oscillating scrolls 3ca and 3cb corresponds to their volume ratio. Therefore, the scroll compressor 100 of the seventh embodiment is configured such that the center of gravity of the upper and lower oscillating scrolls 3ca and 3cb satisfies Da:Db = M2:M1 in terms of the volume ratio and the center of gravity of the involute.

[0102] Here, the volume of the oscillating spiral body can be calculated as an approximate volume, for example, by multiplying the height of the spiral body by the thickness of the spiral body by the involute length.

[0103] (Effects of Scroll Compressor 100 of Seventh Embodiment) Even when the upper and lower oscillating scrolls 3ca and 3b are configured to differ from each other in all of the height, thickness, number of turns, and involute length, the scroll compressor 100 can achieve the same effects as those of the first to sixth embodiments by satisfying Da:Db=M2:M1. In other words, the scroll compressor 100 of the seventh embodiment can achieve the effect of suppressing increases in vibration and noise due to poor balance, as well as an increase in the load on the key portions 5a of the Oldham ring 5.

[0104] Embodiment 8. Embodiment 8 relates to the position of upper oscillating spiral body 3ca on oscillating base plate 3a, and more specifically, to the positional relationship between the center of gravity Ga of upper oscillating spiral body 3ca, the center O of oscillating base plate 3a, and the base circle center 3da1 of upper oscillating spiral body 3ca.

[0105] FIG. 13 is an enlarged view of the center of the oscillating scroll 3 of the scroll compressor 100 according to the eighth embodiment, as viewed from below. The scroll compressor 100 of the eighth embodiment has a configuration in which the intersection Aa of a perpendicular line drawn from the center O of the oscillating base plate 3a to the line A and the line A is located outside the range between the base circle center 3da1 of the upper oscillating scroll 3ca and the center of gravity Ga of the upper oscillating scroll 3ca. Here, the line A passes through the base circle center 3da1 of the upper oscillating scroll 3ca and the center of gravity Ga of the upper oscillating scroll 3ca. Furthermore, in the scroll compressor 100 of the eighth embodiment, the distance Da is greater than the distance D1. In other words, the center of gravity Ga of the upper oscillating scroll 3ca is located radially outward of the base circle center 3da1 of the upper oscillating scroll 3ca. The above configuration can be applied in combination with the configurations of the first to seventh embodiments.

[0106] (Effects of Scroll Compressor 100 of Embodiment 8) The scroll compressor 100 of Embodiment 8 has the same effects as those of Embodiments 1 to 7, as well as the following effect. By adopting the above-described spiral arrangement, the scroll compressor 100 of Embodiment 8 can move the entire upper oscillating scroll 3ca further outward from the oscillating base plate 3a. Therefore, the scroll compressor 100 of Embodiment 8 can form a scroll with a larger displacement when, for example, the upper fixed scroll 1c and the upper oscillating scroll 3ca are asymmetrically shaped.

[0107] Ninth Embodiment The ninth embodiment relates to the position of the lower oscillating spiral body 3cb on the oscillating base plate 3a, and more specifically to the positional relationship between the center of gravity Gb of the lower oscillating spiral body 3cb, the center O of the oscillating base plate 3a, and the base circle center 3db1 of the lower oscillating spiral body 3cb.

[0108] FIG. 14 is an enlarged view of the center of the oscillating scroll 3 of a scroll compressor 100 according to the ninth embodiment, as viewed from below. The scroll compressor 100 of the ninth embodiment has a configuration in which the intersection point Ba of the perpendicular line drawn from the center O of the oscillating base plate 3a to the line B and the line B is located outside the range between the base circle center 3db1 of the lower oscillating scroll 3cb and the center of gravity Gb of the lower oscillating scroll 3cb. Here, the line B passes through the base circle center 3db1 of the lower oscillating scroll 3cb and the center of gravity Gb of the lower oscillating scroll 3cb. Furthermore, in the scroll compressor 100 of the ninth embodiment, the distance Db is greater than the distance D2. That is, the center of gravity Gb of the lower oscillating scroll 3cb is located radially outward of the base circle center 3db1 of the lower oscillating scroll 3cb. The above configuration can be applied in combination with the configurations of the first to eighth embodiments.

[0109] (Effects of Scroll Compressor 100 of Embodiment 9) The scroll compressor 100 of Embodiment 9 has the same effects as those of Embodiments 1 to 8, as well as the following effect. By adopting the above-described spiral arrangement, the scroll compressor 100 of Embodiment 9 can move the entire lower oscillating scroll 3cb further outward from the oscillating base plate 3a. Therefore, the scroll compressor 100 of Embodiment 9 can form a scroll with a larger displacement when, for example, the lower fixed scroll 2c and the lower oscillating scroll 3cb are asymmetrically shaped.

[0110] 1 Upper fixed scroll, 1a Upper fixed base plate, 1b Surface, 1c Upper fixed volute, 1d Discharge port, 1e Upper discharge valve, 2 Lower fixed scroll, 2a Lower fixed base plate, 2aa Thrust surface, 2b Surface, 2c Lower fixed volute, 2d Groove, 3 Oscillating scroll, 3a Oscillating base plate, 3ba Surface, 3bb Surface, 3ca Upper oscillating volute, 3cb Lower oscillating volute, 3d Groove, 3da Base circle center (dotted circle), 3da1 Base circle center, 3db Base circle center (dotted circle), 3db1 Base circle center, 4 Rotating shaft, 4a Lower shaft portion, 4b Eccentric shaft portion, 5 Oldham ring, 5a Key portion, 6 Oil pump, 7 Subframe, 9 Oil reservoir portion, 10 Compression mechanism portion, 11 1. Oscillating bearing, 12 upper bearing portion, 13 lower bearing portion, 20 electric mechanism portion, 21 motor stator, 22 motor rotor, 23 first balance weight, 24 second balance weight, 25 first introduction path, 26 second introduction path, 50 sealed container, 51 suction pipe, 52 discharge pipe, 71 upper compression chamber, 72 lower compression chamber, 91 low pressure space, 92 low stage compression mechanism, 93 high stage compression mechanism, 94 high pressure space, 100 scroll compressor, Aa intersection, Ba intersection, G center of gravity, G1 radial center of gravity, G2 center of gravity, Ga center of gravity, Gb center of gravity, H1 height, H2 height, O center, T1 thickness, T2 thickness.

Claims

1. A compressor comprising: a sealed container; a compression mechanism provided within the sealed container for compressing a refrigerant; an electric mechanism for driving the compression mechanism; and a rotating shaft connecting the compression mechanism and the electric mechanism and transmitting the rotational force of the electric mechanism to the compression mechanism, the compression mechanism comprising: an oscillating scroll having a swinging bed plate, an upper swinging spiral body formed on an upper surface of the oscillating bed plate, and a lower swinging spiral body formed on a lower surface of the oscillating bed plate; an upper fixed scroll disposed above the oscillating scroll, the upper fixed scroll having an upper fixed bed plate and an upper fixed spiral body formed on the lower surface of the upper fixed bed plate and combined with the upper swinging spiral body of the oscillating bed plate; and a lower fixed scroll disposed below the oscillating scroll, the lower fixed scroll having a lower fixed bed plate and a lower fixed spiral body formed on the upper surface of the lower fixed bed plate and combined with the lower swinging spiral body of the oscillating bed plate, the oscillating scroll comprising: A scroll compressor in which a radial center of gravity, which is the radial position of the center of gravity of the orbiting scroll, coincides with the center of the orbiting base plate when viewed in the axial direction of the rotation shaft.

2. A scroll compressor according to claim 1, wherein said upper and lower oscillating scrolls are provided on said oscillating base plate in point symmetry with respect to the center of said oscillating base plate.

3. A scroll compressor as claimed in claim 1 or 2, wherein each of said upper oscillating scroll and said lower oscillating scroll has a shape following an involute curve, the base circle center of the involute of said upper oscillating scroll and the base circle center of the involute of said lower oscillating scroll are offset from the center of said oscillating bed plate, and said upper oscillating scroll and said lower oscillating scroll are provided on said oscillating bed plate point-symmetrically with respect to the center of said oscillating bed plate.

4. A scroll compressor according to any one of claims 1 to 3, wherein the upper fixed scroll and the upper oscillating scroll are asymmetric in shape.

5. A scroll compressor according to any one of claims 1 to 4, wherein the lower fixed scroll and the lower oscillating scroll are asymmetric in shape.

6. A scroll compressor according to any one of claims 1 to 5, wherein the axial height of the upper oscillating scroll is lower than the axial height of the lower oscillating scroll.

7. A scroll compressor according to any one of claims 1 to 5, wherein the axial height of the upper oscillating scroll and the axial height of the lower oscillating scroll are the same.

8. A scroll compressor according to any one of claims 1 to 7, further comprising an Oldham ring disposed between said lower fixed scroll and said orbiting scroll for preventing said orbiting scroll from rotating on its axis.

9. A scroll compressor according to any one of claims 1 to 8, wherein the compression mechanism is provided above the electric mechanism within the sealed container.

10. A scroll compressor as described in any one of claims 1 to 9, wherein the compression mechanism section includes a compression mechanism including the oscillating scroll and the upper fixed scroll, and a compression mechanism including the oscillating scroll and the lower fixed scroll, one of which is a low-stage compression mechanism that compresses refrigerant sucked into the sealed container, and the other is a high-stage compression mechanism that sucks in and compresses the refrigerant compressed by the low-stage compression mechanism.

11. A scroll compressor as described in claim 10, wherein the upper fixed scroll separates a space in the high-stage compression mechanism including the oscillating scroll and the upper fixed scroll from a high-pressure space in the sealed container, the lower fixed scroll separates a space in the low-stage compression mechanism including the oscillating scroll and the lower fixed scroll from a low-pressure space in the sealed container, and the oscillating base plate of the oscillating scroll separates the low-stage compression mechanism from the high-stage compression mechanism.

12. A scroll compressor according to any one of claims 1 to 11, wherein the upper fixed scroll and the lower fixed scroll are fixed to the sealed container.

13. A scroll compressor as claimed in claim 10, and any one of claims 11 to 12 dependent on claim 10, wherein the thickness of the scroll constituting the high-stage compression mechanism out of the upper oscillating scroll and the lower oscillating scroll is greater than the thickness of the scroll constituting the low-stage compression mechanism.

14. A scroll compressor according to any one of claims 1 to 13, wherein the center of gravity of the lower oscillating scroll and the center of gravity of the upper oscillating scroll are located symmetrically with respect to the center of the oscillating base plate.

15. A scroll compressor as claimed in any one of claims 1 to 14, wherein, when the oscillating bed plate is viewed in the axial direction of the rotation shaft, the distance from the center of the oscillating bed plate to the center of gravity of the upper oscillating scroll is Da, the distance from the center of the oscillating bed plate to the center of gravity of the lower oscillating scroll is Db, the weight of the upper oscillating scroll is M1, and the weight of the lower oscillating scroll is M2, satisfying Da:Db=M2:M1.

16. A scroll compressor as claimed in any one of claims 1 to 15, wherein, when the oscillating bed plate is viewed in the axial direction of the rotation shaft, the distance from the center of the oscillating bed plate to the center of gravity of the upper oscillating scroll is Da, the distance from the center of the oscillating bed plate to the center of gravity of the lower oscillating scroll is Db, the involute length of the upper oscillating scroll is l1, and the involute length of the lower oscillating scroll is l2, satisfying Da:Db=l2:l1.

17. A scroll compressor as claimed in any one of claims 1 to 16, wherein an intersection point of a perpendicular line drawn from the center of the oscillating bed plate to a line passing through the base circle center of the upper oscillating scroll and the center of gravity of the upper oscillating scroll and the straight line is located outside the range on the straight line between the base circle center of the upper oscillating scroll and the center of gravity of the upper oscillating scroll, and a distance Da from the center of the oscillating bed plate to the center of gravity of the upper oscillating scroll when the oscillating bed plate is viewed in the axial direction of the rotation shaft is greater than a distance D1 from the center of the oscillating bed plate to the base circle center of the upper oscillating scroll.

18. A scroll compressor as claimed in any one of claims 1 to 17, wherein an intersection point of a perpendicular line drawn from the center of the oscillating table plate to a line passing through the base circle center of the lower oscillating scroll and the center of gravity of the lower oscillating scroll is located outside the range on the line between the base circle center of the lower oscillating scroll and the center of gravity of the lower oscillating scroll, and a distance Db from the center of the oscillating table plate to the center of gravity of the lower oscillating scroll is greater than a distance D2 from the center of the oscillating table plate to the base circle center of the lower oscillating scroll.

19. A scroll compressor as claimed in claim 10 and any one of claims 11 to 18 dependent on claim 10, wherein the high-stage compression mechanism is comprised of the upper oscillating scroll and the upper fixed scroll of the oscillating scroll, the low-stage compression mechanism is comprised of the lower oscillating scroll and the lower fixed scroll, and the lower fixed base plate of the lower fixed scroll has an introduction path for guiding refrigerant compressed in the low-stage compression mechanism to the high-stage compression mechanism, the introduction path being formed to penetrate the lower fixed base plate so that its upstream end opens into the compression chamber of the low-stage compression mechanism and its downstream end opens into the compression chamber of the high-stage compression mechanism.

20. A scroll compressor as claimed in any one of claims 1 to 19, wherein the eccentric shaft portion located at the end of the rotating shaft is inserted into a rocking bearing provided on the rocking plate and connected to the rocking plate without penetrating the rocking plate.

Images