JP7408011B2 - two-stage scroll compressor - Google Patents

Description

The present disclosure mainly relates to a two-stage scroll compressor installed in a refrigerator, an air conditioner, and a water heater.

Conventionally, a multi-stage scroll compressor includes a closed container, a plurality of compression mechanism sections disposed in the closed container and compressing a refrigerant, and a drive mechanism section that drives the plurality of compression mechanism sections. The mechanism section is disposed between two of the plurality of compression mechanism sections, and the sealed container includes a low pressure space into which one of the plurality of compression mechanism sections sucks the refrigerant, and a low pressure space from which one of the plurality of compression mechanism sections sucks the refrigerant. an intermediate pressure space in which the refrigerant is compressed and discharged by one of the plurality of compression mechanism sections, and the refrigerant sucked from the intermediate pressure space is compressed in a different one of the plurality of compression mechanism sections. Each of the plurality of compression mechanism parts has a compression chamber formed by combining a fixed scroll and an oscillating scroll with a spiral body protruding from the base plate. A technique is known in which performance is maintained by configuring (for example, see Patent Document 1).

Patent No. 6689414

In a two-stage scroll compressor such as Patent Document 1, which includes two compression mechanism sections and a drive mechanism section in a closed container, and the drive mechanism section is arranged between the two compression mechanism sections, an oscillating scroll, etc. The number of eccentric parts (hereinafter referred to as eccentric parts) is greater than in the case of single-stage eccentric parts, so if the balanced design of eccentric parts is not appropriate, the efficiency of the compressor may decrease, and vibration and noise may be caused. There were issues such as an increase in

The present disclosure has been made to solve the above-mentioned problems, and by appropriately designing the balance of eccentric parts, it is possible to suppress a decrease in compressor efficiency and an increase in vibration and noise. The purpose is to provide a two-stage scroll compressor.

A two-stage scroll compressor according to the present disclosure includes a hermetic container that forms an outer shell, a drive mechanism section that is disposed within the hermetic container and serves as a drive source, and a drive mechanism section that is disposed above and below the drive mechanism section; two compression mechanism sections each having a compression chamber formed by combining a fixed scroll fixed in a closed container and an oscillating scroll driven by the drive mechanism section; A crankshaft that transmits transmission to an oscillating scroll, a balancer that is provided on the crankshaft and that offsets the imbalance caused by the two oscillating scrolls, and two Oldham rings that prevent each of the oscillating scrolls from rotating. , the two oscillating scrolls are eccentric in the same direction with respect to the central axis of the crankshaft, and the closed container is a low-pressure space into which fluid is sucked by one of the two compression mechanisms; An intermediate pressure space from which the fluid compressed by one of the two compression mechanism parts is discharged, and a high pressure space from which the fluid compressed by the other of the two compression mechanism parts is discharged. The two compression mechanism sections have an internal space, and the two compression mechanism sections include a first compression mechanism section that compresses the fluid taken in from the low pressure space and discharges it into the intermediate pressure space; a second compression mechanism section that compresses and discharges it into the high-pressure space, and the two Oldham rings are configured such that their simple harmonic directions are orthogonal to each other, and the first compression mechanism section The mass of the Oldham ring is Mold1, the mass of the Oldham ring of the second compression mechanism section is Mold2, the revolution radius of the oscillating scroll of the first compression mechanism section is R1, and the rocking motion of the second compression mechanism section. When the revolution radius of the scroll is R2, the two Oldham rings are configured to satisfy 0.95≦(Mold2×R2/Mold1×R1)≦1.05 .

According to the two-stage scroll compressor according to the present disclosure, since the two swinging scrolls, which are eccentric components, are eccentric in the same direction with respect to the central axis of the crankshaft, a balancer is installed between the two compression mechanism parts. can be placed. As a result, it is possible to secure the displacement amount, which suppresses a decrease in the efficiency of the compressor, and also to reduce imbalances in static and dynamic balance, suppressing increases in vibration and noise. .

1 is a sectional view of a two-stage scroll compressor according to Embodiment 1. FIG. FIG. 3 is a diagram showing directions of simple vibration of two Oldham rings of the two-stage scroll compressor according to the first embodiment. FIG. 2 is a schematic diagram showing the positional relationship between two swinging scrolls and two Oldham rings of the two-stage scroll compressor according to the first embodiment. FIG. 3 is a diagram showing the inertia force acting on the rocking scroll and the balancer during one rotation of the two-stage scroll compressor according to the first embodiment. FIG. 3 is a diagram showing an inertial force acting in an eccentric direction on an Oldham ring during one rotation of the two-stage scroll compressor according to the first embodiment. When each component is arranged so that the simple harmonic directions of the two Oldham rings of the two-stage scroll compressor according to the first embodiment are orthogonal to each other, the eccentric direction that acts on each of the two Oldham rings during one rotation It is a figure showing the inertial force which acts on. When each component is arranged so that the simple harmonic directions of the two Oldham rings of the two-stage scroll compressor according to the first embodiment coincide, the eccentric direction that acts on each of the two Oldham rings during one rotation is It is a figure showing the inertial force which acts. When each component is arranged so that the simple harmonic directions of the two Oldham rings of the two-stage scroll compressor according to the second embodiment are orthogonal to each other, the eccentric direction that acts on each of the two Oldham rings during one rotation. It is a figure showing the inertial force which acts on. FIG. 7 is a schematic diagram showing the positional relationship between two swinging scrolls and a balancer of a two-stage scroll compressor according to a third embodiment. FIG. 3 is a sectional view of a two-stage scroll compressor according to a fourth embodiment.

Embodiments of the present disclosure will be described below based on the drawings. Note that the present disclosure is not limited to the embodiments described below. Further, in the following drawings, the size relationship of each component may differ from the actual one.

Embodiment 1.
FIG. 1 is a sectional view of a two-stage scroll compressor 100 according to the first embodiment.

The two-stage scroll compressor 100 according to the first embodiment has a function of sucking in a fluid such as a refrigerant, compressing it, and discharging it in a high temperature and high pressure state. As shown in FIG. 1, the two-stage scroll compressor 100 includes a closed container 11 forming an outer shell. Inside the airtight container 11, a first compression mechanism section 35, a second compression mechanism section 36, a drive mechanism section 37, and other components are housed. In the closed container 11, a first compression mechanism section 35 is disposed above the drive mechanism section 37, and a second compression mechanism section 36 is disposed below the drive mechanism section 37. The two-stage scroll compressor 100 performs two-stage compression with the first compression mechanism section 35 on the low stage side and the second compression mechanism section 36 on the high stage side. That is, in the two-stage scroll compressor 100, after the first compression mechanism section 35 compresses the fluid, the second compression mechanism section 36 further compresses the fluid. Further, the lower part of the closed container 11 serves as an oil reservoir 20.

The airtight container 11 includes a low pressure space 22 into which fluid is sucked by the first compression mechanism section 35, an intermediate pressure space 23 from which fluid compressed by the first compression mechanism section 35 is discharged, and a second compression mechanism section 36. It has three internal spaces: a high pressure space 24 from which compressed fluid is discharged.

The first compression mechanism section 35 has a function of compressing the fluid sucked in from the suction pipe 8 communicating with piping outside the closed container 11 and discharging it into the intermediate pressure space 23 inside the closed container 11 . Further, the second compression mechanism section 36 has a function of compressing the fluid taken in from the intermediate pressure space 23 and discharging it into the high pressure space 24 formed below in the closed container 11 . The high-pressure fluid discharged into the high-pressure space 24 is discharged from the discharge pipe 9 to the outside of the closed container 11 . In order to compress fluid, the drive mechanism section 37 includes a first swinging scroll 2 forming a first compression mechanism section 35 and a second swinging scroll 5 forming a second compression mechanism section 36. It has the function of driving each. That is, the drive mechanism section 37 drives the first swinging scroll 2 and the second swinging scroll 5 via the crankshaft 7, so that the first compression mechanism section 35 and the second compression mechanism section 36 generate fluid. It is designed to be compressed.

The first compression mechanism section 35 includes a first fixed scroll 1 and a first swinging scroll 2. The first swinging scroll 2 is arranged on the lower side, and the first fixed scroll 1 is arranged on the upper side. The first fixed scroll 1 includes a first fixed base plate 1c and a first fixed spiral body 1b which is a spiral protrusion provided on one surface of the first fixed base plate 1c. The first swinging scroll 2 includes a first swinging base plate 2c and a first swinging spiral body 2b which is a spiral protrusion provided on one surface of the first swinging base plate 2c. Here, the first fixed spiral body 1b and the first oscillating spiral body 2b each have a shape extending along a curve such as an involute or an algebraic spiral. The first fixed scroll 1 and the first swing scroll 2 are provided in the closed container 11 with the first fixed scroll body 1b and the first swing scroll body 2b being engaged with each other. A first compression chamber 12 whose volume decreases radially inward is formed between the first fixed spiral body 1b and the first oscillating spiral body 2b.

The first fixed scroll 1 is fixed inside the closed container 11 via the first frame 3 fixed to the closed container 11. A first discharge port 1a is formed in the center of the first fixed scroll 1 to discharge fluid that has been compressed and has an intermediate pressure. A first valve 15 made of a leaf spring is disposed at the outlet opening of the first discharge port 1a to cover the outlet opening and prevent backflow of fluid. A first valve holder 14 that limits the amount of lift of the first valve 15 is provided at one end of the first valve 15 . In other words, when the fluid is compressed to an intermediate pressure in the center of the first compression chamber 12, the first valve 15 is lifted against its elastic force, and the compressed fluid flows from the first discharge port 1a to the flow path 35a. and is discharged into the intermediate pressure space 23.

In addition to the first discharge port 1a, the first fixed scroll 1 is formed with a subport 1d that communicates with the intermediate pressure space 23. A subport valve 29 made of a leaf spring is disposed at the outlet opening of the subport 1d to cover the outlet opening and prevent backflow of fluid. A sub-port valve holder 28 is provided at one end of the sub-port valve 29 to limit the amount of lift of the sub-port valve 29. That is, when the fluid in the middle of compression in the first compression chamber 12 is compressed to an intermediate pressure or higher, the sub-port valve 29 is lifted against its elastic force, and the compressed fluid passes from the sub-port 1d through the flow path 35a to the intermediate pressure. It is discharged into the pressure space 23.

The first swinging scroll 2 is configured to perform an eccentric rotation motion with respect to the first fixed scroll 1 without rotating due to the first Oldham ring 25. Further, a first swing bearing portion 2d is formed in the center of the first swing scroll 2 to receive a driving force. The first swing bearing portion 2d has a concave shape into which the upper end portion of the crankshaft 7 is fitted. The first swing bearing part 2d of the first swing scroll 2 is fitted with a first eccentric part 7a, which is an upper end part of a crankshaft 7, which will be described later, with a slight gap.

The second compression mechanism section 36 includes a second fixed scroll 4 and a second swinging scroll 5. The second swinging scroll 5 is arranged on the upper side, and the second fixed scroll 4 is arranged on the lower side. The second fixed scroll 4 includes a second fixed base plate 4c and a second fixed spiral body 4b which is a spiral protrusion provided on one surface of the second fixed base plate 4c. The second swinging scroll 5 includes a second swinging base plate 5c and a second swinging spiral body 5b which is a spiral protrusion provided on one surface of the second swinging base plate 5c. Here, the second fixed spiral body 4b and the second oscillating spiral body 5b each have a shape extending along a curve such as an involute or an algebraic spiral. The second fixed scroll 4 and the second swinging scroll 5 are provided in the closed container 11 in a state where the second fixed scroll body 4b and the second swing scroll body 5b are engaged with each other. A second compression chamber 13 whose volume decreases radially inward is formed between the second fixed spiral body 4b and the second oscillating spiral body 5b.

The second fixed scroll 4 is fixed inside the closed container 11 via a second frame 6 fixed to the closed container 11. A second discharge port 4a is formed in the center of the second fixed scroll 4 to discharge fluid that has been compressed and has an intermediate pressure. A second valve 17 made of a plate spring is disposed at the outlet opening of the second discharge port 4a to cover the outlet opening and prevent backflow of fluid. A second valve holder 16 that limits the lift amount of the second valve 17 is provided at one end of the second valve 17 . That is, when the fluid is compressed to a predetermined pressure within the second compression chamber 13, the second valve 17 is lifted against its elastic force. Then, the compressed fluid is discharged from the second discharge port 4a to the high pressure space 24 in the chamber 30 attached to the back surface of the second fixed scroll 4, and is discharged to the outside of the closed container 11 through the discharge pipe 9. Note that a space surrounded by the chamber 30 and the back surface of the second fixed scroll 4 forms a high-pressure space 24 that communicates with the second discharge port 4a.

The second swinging scroll 5 is configured to perform an eccentric rotation movement with respect to the second fixed scroll 4 without rotating due to the second Oldham ring 26. Further, a second swing bearing portion 5d is formed in the center of the second swing scroll 5 to receive a driving force. The second swing bearing portion 5d has a hole that penetrates in the vertical direction so that the lower end portion of the crankshaft 7 is fitted therein. A second swing bearing portion 5d of the second swing scroll 5 is fitted into a second eccentric portion 7b, which is a lower end portion of the crankshaft 7, which will be described later, with a slight gap therebetween.

The drive mechanism section 37 includes a stator 19 fixedly held in the sealed container 11 , a rotor 18 rotatably arranged on the inner peripheral surface of the stator 19 and fixed to the crankshaft 7 , and a rotor 18 fixed to the crankshaft 7 . The crankshaft 7 is housed in the direction of the rotor 18 and rotates integrally with the rotor 18. The stator 19 has a function of rotationally driving the rotor 18 when energized. Further, the outer peripheral surface of the stator 19 is fixedly supported on the closed container 11 by shrink fitting, spot welding, or the like. The rotor 18 has a function of being rotationally driven by energizing the stator 19 and rotating the crankshaft 7 . This rotor 18 has a permanent magnet inside. Further, the rotor 18 is fixed to the outer periphery of the crankshaft 7, and is held with a small gap from the stator 19.

The crankshaft 7 rotates as the rotor 18 rotates, and rotates the first swinging scroll 2 and the second swinging scroll 5. The crankshaft 7 is rotatably supported by a bearing 3a located at the center of the first frame 3 on the upper side and a bearing 6a located at the center of the second frame 6 at the lower side. A second eccentric part 7b is provided at the lower end of the crankshaft 7 and fits into the second swing bearing part 5d so that the second swing scroll 5 can rotate eccentrically. Furthermore, a first eccentric portion 7a is provided at the upper end of the crankshaft 7, which fits into the first swing bearing portion 2d so that the first swing scroll 2 can rotate eccentrically. Further, the first eccentric portion 7a and the second eccentric portion 7b are provided so that their eccentric directions coincide with each other. This is to ensure that the first orbiting scroll 2 and the second orbiting scroll 5 are eccentric in the same direction with respect to the central axis of the crankshaft 7, so that the eccentric directions coincide with each other.

The crankshaft 7 is provided with a balancer 31 that offsets the unbalance caused by the swinging of the first swinging scroll 2 and the second swinging scroll 5 and the simple harmonic motion of the first Oldham ring 25 and the second Oldham ring 26. ing. This balancer 31 is eccentric with respect to the central axis of the crankshaft 7 in a direction opposite to the eccentric direction of the first orbiting scroll 2 and the second orbiting scroll 5. In addition, taking into account manufacturing errors, if the angle θ between the eccentric direction of the balancer 31 and the two oscillating scrolls is within the range of 180°±5°, the balancer 31 will be aligned with the central axis of the crankshaft 7. On the other hand, it is assumed that the two orbiting scrolls are eccentric in a direction opposite to that of the two orbiting scrolls. Here, θ is measured from the central axis of the crankshaft 7 toward the center of gravity of the balancer 31 and the center of the eccentric axis of one eccentric part of the two oscillating scrolls, respectively, when viewed from above of the two-stage scroll compressor 100. Draw a straight line and find the angle between the two straight lines.

A suction pipe 8 for sucking in fluid, a discharge pipe 9 for discharging fluid, and an injection pipe 10 for introducing fluid that cools intermediate pressure space 23 are connected to the closed container 11, respectively.

Inside the airtight container 11, a first frame 3 and a second frame 6 are fixed. The first frame 3 is fixed to the inner circumferential surface of the closed container 11 and above the drive mechanism section 37, and has a through hole 3c formed in the center thereof for pivotally supporting the crankshaft 7. The first frame 3 rotatably supports the crankshaft 7 using a bearing portion 3a. The bearing portion 3a is constituted by, for example, a sliding bearing. Further, the second frame 6 is fixed to the inner circumferential surface of the closed container 11 and below the drive mechanism section 37, and has a through hole 6d formed in the center thereof to pivotally support the crankshaft 7. Further, a flow path 6b for guiding fluid to the second compression chamber 13 is formed inside the second frame 6, and a second suction port 6c, which is an inlet of the flow path 6b, is formed in the upper part of the second frame 6. is formed. The second frame 6 supports the second swinging scroll 5 and rotatably supports the crankshaft 7 with a bearing portion 6a. Note that it is preferable that the outer peripheral surface of the second frame 6 is fixed to the inner peripheral surface of the closed container 11 by shrink fitting, spot welding, or the like.

An oil pump 21 is fixed to the lower side of the crankshaft 7, and a through hole 4e is provided in the second fixed scroll 4 so that the rotational force of the crankshaft 7 can be transmitted to the oil pump 21. The oil pump 21 is a positive displacement pump, and as the crankshaft 7 rotates, the refrigerating machine oil held in the oil reservoir 20 is passed through an oil circuit (not shown) provided inside the crankshaft 7 to the first swing bearing. 2d, the bearing portion 3a, the thrust bearing portion 3b, the second swing bearing portion 5d, and the bearing portion 6a.

In the airtight container 11, there is a first Oldham ring 25 for preventing the rotation movement of the first oscillating scroll 2 during the eccentric rotation movement, and a ring 25 for preventing the rotation movement of the second oscillation scroll 5 during the eccentric rotation movement. A second Oldham ring 26 is arranged for each. The first Oldham ring 25 is arranged between the first swinging scroll 2 and the first frame 3, and has the function of preventing the first swinging scroll 2 from rotating on its axis and allowing it to revolve. It has become. Further, the second Oldham ring 26 is disposed between the second swinging scroll 5 and the second frame 6, and has the function of preventing the second swinging scroll 5 from rotating on its own axis and allowing it to revolve. It looks like this.

Here, the operation of the two-stage scroll compressor 100 will be briefly explained using FIG. 1. Note that in the following, it is assumed that the fluid is a refrigerant.
When power is supplied to a power terminal (not shown) provided in the sealed container 11, torque is generated in the stator 19 and the rotor 18, and the crankshaft 7 rotates. A first oscillating scroll 2 is rotatably fitted into the first eccentric portion 7a of the crankshaft 7, and a second oscillating scroll 5 is rotatably fitted into the second eccentric portion 7b of the crankshaft 7. has been done. Further, the first oscillating scroll body 2b of the first oscillating scroll 2 and the first fixed scroll body 1b of the first fixed scroll 1 are engaged with each other, and a plurality of first compression chambers 12 are formed. Further, the second oscillating scroll body 5b of the second oscillating scroll 5 and the second fixed scroll body 4b of the second fixed scroll 4 engage with each other, and a plurality of second compression chambers 13 are formed.

The first compression chamber 12 that takes in gas from the suction pipe 8 reduces its volume while moving from the outer periphery toward the center as the first swinging scroll 2 moves eccentrically, thereby compressing the refrigerant. Here, the refrigerant compressed in the first compression chamber 12 is carbon dioxide alone or a mixed refrigerant containing carbon dioxide. In this way, by using carbon dioxide alone or a mixed refrigerant containing carbon dioxide, which has a low GWP, as the refrigerant compressed by the two-stage scroll compressor 100, it is possible to contribute to suppressing global warming. The refrigerant gas compressed in the first compression chamber 12 is discharged from the first discharge port 1 a provided in the first fixed scroll 1 into the intermediate pressure space 23 against the first valve 15 . The refrigerant compressed in the first compression chamber 12 mixes with the refrigerant flowing in from the injection pipe 10.

Then, the second compression chamber 13 that takes in gas from the intermediate pressure space 23 reduces its volume while moving from the outer circumference toward the center as the second swinging scroll 5 moves eccentrically, thereby compressing the refrigerant. The refrigerant gas compressed in the second compression chamber 13 is discharged from the second discharge port 4 a provided in the second fixed scroll 4 against the second valve 17 and discharged from the discharge pipe 9 to the outside of the closed container 11 . Note that the first valve 15 and the second valve 17 are regulated by a first valve holder 14 and a second valve holder 16, respectively, so that they do not deform more than necessary. Prevents damage.

In addition, in the following, the first Oldham ring 25 and the second Oldham ring 26 will be collectively referred to as two Oldham rings, and the same shall apply to the generic terms of two components such as "first" and "second".

FIG. 2 is a diagram showing the simple harmonic directions of each of the two Oldham rings of the two-stage scroll compressor 100 according to the first embodiment. Note that FIG. 2(a) shows the simple harmonic direction of the first Oldham ring 25, and FIG. 2(b) shows the simple harmonic direction of the second Oldham ring 26. Moreover, FIG. 2 is a diagram of the two Oldham rings seen from above of the two-stage scroll compressor 100, and in FIGS. 2(a) and 2(b), the first swing key in the circumferential direction is The illustration is made so that the position of the groove 2e and the position of the second frame key groove 6e coincide with each other.

The first Oldham ring 25 has a ring portion 25a and two pairs of first Oldham keys 25b formed on the upper and lower surfaces of the ring portion 25a. The two first Oldham keys 25b on the upper surface are inserted into two first swing key grooves 2e formed in the first swing scroll 2, respectively, and are slidable in one direction. Further, the two first Oldham keys 25b on the lower surface are inserted into two first frame key grooves 3e formed in the first frame 3, respectively, and are slidable in a direction intersecting the one direction. . With this configuration, the first swing scroll 2 does not rotate but revolves around its axis.

The second Oldham ring 26 has a ring portion 26a and two pairs of second Oldham keys 26b formed on the upper and lower surfaces of the ring portion 26a. The second Oldham key 26b on the upper surface is inserted into a second frame key groove 6e formed in the second frame 6, and is slidable in one direction. Further, the second Oldham key 26b on the lower surface is inserted into a second swing keyway 5e formed in the second swing scroll 5, and is slidable in a direction intersecting the one direction. With this configuration, the second swinging scroll 5 is configured to revolve around itself without rotating.

The first frame 3 is installed so that the two first frame keyways 3e are aligned in the left-right direction in the paper of FIG. 2(a), and the simple harmonic direction of the first Oldham ring 25 is indicated by the arrow in FIG. 2(a). The direction is as shown. Further, the second frame 6 is installed in such a direction that the two second frame key grooves 6e are lined up in the vertical direction on the paper of FIG. 2(b) orthogonal to the two first frame key grooves 3e, and The direction of simple harmonic motion is the direction shown by the arrow in FIG. 2(b). As a result, the simple harmonic directions of the first Oldham ring 25 and the second Oldham ring 26 are orthogonal to each other.

FIG. 3 is a schematic diagram showing the positional relationship between two swing scrolls and two Oldham rings of the two-stage scroll compressor 100 according to the first embodiment. In order to simplify the explanation, it is assumed that the center of gravity of the two swinging scrolls is on the eccentric axis E2, and that the radius of revolution of the two swinging scrolls is the same.

FIG. 3 is a view from the direction in which the first swing keyways 2e are lined up from the front to the back of the paper, and when the two-stage scroll compressor 100 is being driven, A state in which the portion 7b is located on the right side in FIG. 3 is shown. The direction of simple vibration of the first Oldham ring 25 is the left-right direction in FIG. 3, and the center of gravity position B of the first Oldham ring 25 always overlaps with the eccentric axis E2 during rotation. On the other hand, the direction of simple harmonic motion of the second Oldham ring 26 is perpendicular to the plane of FIG. 3, and the center of gravity D of the second Oldham ring 26 always overlaps with the central axis E1 of the crankshaft 7 during rotation.

FIG. 4 is a diagram showing the inertial force acting on the rocking scroll and balancer 31 during one rotation of the two-stage scroll compressor 100 according to the first embodiment. Although FIG. 4 shows one of the two swinging scrolls, a similar straight line is shown for the other one as well.
As shown in FIG. 4, centrifugal force acts on the rocking scroll and balancer 31 during rotation, and the inertial force acting on the rocking scroll and balancer 31 during one rotation remains constant.

FIG. 5 is a diagram showing the inertia force acting on the Oldham ring in the eccentric direction during one rotation of the two-stage scroll compressor 100 according to the first embodiment. Although FIG. 5 shows one of the two Oldham rings, the other one also shows a similar waveform.
As shown in FIG. 5, the motion of the Oldham ring is simple harmonic motion, unlike the oscillating scroll and the balancer 31, so the inertial force acting on the Oldham ring during one rotation changes periodically. Therefore, it is theoretically impossible to achieve perfect balance using the balancer 31, which always exerts a constant inertial force.

FIG. 6 shows that when each component is arranged so that the simple harmonic directions of the two Oldham rings of the two-stage scroll compressor 100 according to the first embodiment are orthogonal to each other, each of the two Oldham rings changes during one rotation. FIG. 3 is a diagram showing an inertial force acting in an eccentric direction.
As shown in FIG. 6, there is a difference of 90° between the period of simple harmonic motion of the first Oldham ring 25 and the period of simple harmonic motion of the second Oldham ring 26. Therefore, the sum of the inertial forces acting on each of the two Oldham rings during one rotation is equalized.

FIG. 7 shows the effect on each of the two Oldham rings during one rotation when each component is arranged so that the simple harmonic directions of the two Oldham rings of the two-stage scroll compressor 100 according to the first embodiment coincide. FIG. 3 is a diagram showing inertial force acting in an eccentric direction.
As shown in FIG. 7, the period of simple harmonic motion of the first Oldham ring 25 and the period of simple harmonic motion of the second Oldham ring 26 match. Therefore, the sum of inertial forces acting on each of the two Oldham rings during one rotation is not equalized.

In addition, the two-stage scroll compressor 100 according to the first embodiment has the first compression mechanism section 35 and the suction pipe 8 on the upper side of the drive mechanism section 37, and the second compression mechanism section 36 and the discharge pipe 9 on the lower side. However, the present invention is not limited thereto, and they may be arranged upside down. That is, the first compression mechanism section 35 and the suction pipe 8 may be arranged below the drive mechanism section 37, and the second compression mechanism section 36 and the discharge pipe 9 may be arranged above it.

Further, in the two-stage scroll compressor 100 according to the first embodiment, the balancer 31 is arranged above the drive mechanism section 37; however, the balancer 31 is not limited thereto, and may be arranged below the drive mechanism section 37. Good too.

Further, in the two-stage scroll compressor 100 according to the first embodiment, as shown in FIG. 2, the two Oldham rings each have a key, and the two frames each have a keyway, but the configuration is limited to this. Not done. It is sufficient that each of the two oscillating scrolls has a function that allows it to revolve without rotating, for example, two Oldham rings each have a keyway, and two frames each have a key. But that's fine.

(Effects of Embodiment 1)
As described above, the two-stage scroll compressor 100 according to the first embodiment includes the hermetic container 11 constituting the outer shell, the drive mechanism section 37 disposed inside the hermetic container 11 and serving as a drive source, and the upper and lower parts of the drive mechanism section 37. Two compression mechanism sections each having a compression chamber formed by combining a fixed scroll arranged on the lower side and fixed in the closed container 11 and an oscillating scroll driven by the drive mechanism section 37; and a drive mechanism section 37. a crankshaft 7 that transmits the driving force of the two oscillating scrolls to the two oscillating scrolls, and a balancer 31 that is provided on the crankshaft 7 and cancels out the unbalance caused by the two oscillating scrolls. It is eccentric in the same direction with respect to the central axis E1 of the shaft 7.

According to the two-stage scroll compressor 100 according to the first embodiment, the two swinging scrolls, which are eccentric components, are eccentric in the same direction with respect to the central axis E1 of the crankshaft 7, so that the two compression mechanisms A balancer 31 can be placed between the parts. As a result, it is possible to secure the displacement amount, which suppresses a decrease in the efficiency of the compressor, and also to reduce imbalances in static and dynamic balance, suppressing increases in vibration and noise. . In addition, considering manufacturing errors, if the angle θ1 between the eccentric directions of the two oscillating scrolls is within the range of 0°±5°, the two oscillating scrolls will align with the central axis E1 of the crankshaft 7. It is assumed that they are eccentric in the same direction. This means that even if the two-stage scroll compressor 100 is manufactured so that θ1 is 0°, some variation will occur, but as long as θ1 is within the range of 0°±5°, the same effect as above can be obtained. This is so that you can be saved.

In addition, since the two eccentric parts of the crankshaft 7 are fitted into the bearing parts of the two rocking scrolls, the angle formed by the eccentric directions of the two rocking scrolls is the angle between the two eccentric parts of the crankshaft 7. It is the same as the angle formed by Therefore, θ1 is calculated by drawing a straight line from the central axis E1 of the crankshaft 7 toward the center of the eccentric shaft of the two eccentric parts when viewed from above of the two-stage scroll compressor 100, and determining the angle formed by the two straight lines. is the same as

Here, let us consider a case where the two swinging scrolls are not eccentric in the same direction with respect to the central axis E1 of the crankshaft 7.
For example, when θ1=180°, in order to eliminate the unbalance of static balance and dynamic balance caused by the two oscillating scrolls, the balancer 31 should be placed above the first compression mechanism section 35 or below the second compression mechanism section 36. It needs to be placed in In other words, the balancer 31 cannot be placed between the two compression mechanisms.

When the balancer 31 is disposed above the first compression mechanism section 35, the first fixed scroll 1 and the first swinging scroll 2 are connected to the crankshaft in order to extend the crankshaft 7 to the top of the first compression mechanism section 35. It is necessary to penetrate with 7. Then, the central portions of the first fixed scroll 1 and the first swinging scroll 2 are occupied by the crankshaft 7 and its bearing portion. Therefore, when the balancer 31 is disposed above the first compression mechanism section 35, the amount of displacement cannot be increased beyond a certain amount.

On the other hand, when the balancer 31 is disposed below the second compression mechanism section 36, the balancer 31 is immersed in the refrigerating machine oil in the oil reservoir 20. Then, the balancer 31 rotates while immersed in refrigerating machine oil, resulting in a decrease in compressor efficiency due to oil agitation loss. Further, when 0°<θ1<180°, the central axis E1 of the crankshaft 7 and the two eccentric shafts are not in a straight line when the two-stage scroll compressor 100 is viewed from above. Therefore, one balancer 31 cannot eliminate the unbalance between the static balance and the dynamic balance caused by the two swinging scrolls. Furthermore, compared to the case where θ1=0°, the amount of unbalance in static balance and dynamic balance becomes larger.

Further, the two-stage scroll compressor 100 according to the first embodiment includes two Oldham rings that prevent rotation of each oscillating scroll, and the two Oldham rings are configured such that the simple harmonic directions are orthogonal to each other. There is.

According to the two-stage scroll compressor 100 according to the first embodiment, since the two Oldham rings are configured such that their simple harmonic directions are orthogonal to each other, the inertia force acting in the eccentric direction of the two Oldham rings can be leveled. As a result, increases in vibration and noise can be further suppressed. In addition, considering manufacturing errors, if the angle θ2 formed by the simple harmonic directions of the two Oldham rings is within the range of 90° ± 5°, the simple harmonic directions of the two Oldham rings are orthogonal to each other. shall be taken as a thing. This means that even if the two-stage scroll compressor 100 is manufactured so that θ2 is 90°, some variation will occur, but as long as θ2 is within the range of 90°±5°, the same effect as above can be obtained. This is so that you can be saved.

In the two-stage scroll compressor 100 according to the first embodiment, the balancer 31 is eccentric with respect to the central axis E1 of the crankshaft 7 in a direction opposite to the eccentric direction of the two oscillating scrolls.

According to the two-stage scroll compressor 100 according to the first embodiment, the balancer 31 is eccentric in the opposite direction to the eccentric direction of the two oscillating scrolls with respect to the central axis E1 of the crankshaft 7, so that static balance and Dynamic imbalance can be minimized, and increases in vibration and noise can be further suppressed.

Embodiment 2.
Embodiment 2 will be described below, but the description of parts that overlap with Embodiment 1 will be omitted, and the same or corresponding parts as in Embodiment 1 will be given the same reference numerals.

In the two-stage scroll compressor 100 according to the second embodiment, the mass of the first Oldham ring 25 is Mold1, the revolution radius of the first oscillating scroll 2 is R1, the mass of the second Oldham ring 26 is Mold2, and the second oscillating When the revolution radius of the scroll 5 is R2, the two Oldham rings are configured to satisfy the following formula (1).

0.95≦(Mold2×R2/Mold1×R1)≦1.05
・・・・・・(1)

Here, if the product of the mass of the part and the radius of revolution is defined as the amount of eccentricity, then Mold1×R1 is the amount of eccentricity of the first Oldham ring 25, and Mold2×R2 is the amount of eccentricity of the second Oldham ring 26. . In other words, equation (1) indicates that the ratio of the eccentricity of the second Oldham ring 26 to the eccentricity of the first Oldham ring 25 is 0.95 or more and 1.05 or less, and the eccentricity of the first Oldham ring 25 is This shows that the amount and the amount of eccentricity of the second Oldham ring 26 are almost the same.

FIG. 8 shows that when each component is arranged so that the simple harmonic directions of the two Oldham rings of the two-stage scroll compressor 100 according to the second embodiment are orthogonal to each other, each of the two Oldham rings changes during one rotation. FIG. 3 is a diagram showing an inertial force acting in an eccentric direction.
When two Oldham rings are configured to satisfy equation (1), as shown in FIG. 8, the inertia forces acting on each of the two Oldham rings in the eccentric direction become the same. Therefore, the sum of inertial forces acting on each of the two Oldham rings during one rotation is constant.

(Effects of Embodiment 2)
In the two-stage scroll compressor 100 according to the second embodiment, the mass of the first Oldham ring 25 of the first compression mechanism section 35 is Mold1, the mass of the second Oldham ring 26 of the second compression mechanism section 36 is Mold2, and the mass of the second Oldham ring 26 of the second compression mechanism section 36 is Mold2. When the revolution radius of the first oscillating scroll 2 of the compression mechanism section 35 is R1, and the revolution radius of the second oscillating scroll 5 of the second compression mechanism section 36 is R2, the two Oldham rings are 0.95≦. It is configured to satisfy (Mold2×R2/Mold1×R1)≦1.05.

According to the two-stage scroll compressor 100 according to the second embodiment, the two Oldham rings are configured to satisfy 0.95≦(Mold2×R2/Mold1×R1)≦1.05. The inertia forces acting on each of the two Oldham rings in the eccentric direction are the same. Therefore, the sum of inertial forces acting on each of the two Oldham rings during one rotation can be kept constant. As a result, the rotating balancer 31 makes it possible to reduce the static unbalance amount to zero.

Embodiment 3.
Embodiment 3 will be described below, but the description of parts that overlap with Embodiments 1 and 2 will be omitted, and the same or corresponding parts as in Embodiments 1 and 2 will be given the same reference numerals.

In the two-stage scroll compressor 100 according to the third embodiment, the mass of the first orbiting scroll 2 is Morb1, the revolution radius of the first orbiting scroll 2 is R1, the mass of the second orbiting scroll 5 is Morb2, and the mass of the second orbiting scroll 5 is Morb2. When the revolution radius of the swinging scroll 5 is R2, the two swinging scrolls are configured to satisfy the following equation (2).

0.95≦(Morb2×R2/Morb1×R1)≦1.05
...(2)

Here, if the product of the mass of the part and the radius of revolution is defined as the amount of eccentricity, then Morb1×R1 is the amount of eccentricity of the first swinging scroll 2, and Morb2×R2 is the amount of eccentricity of the first swinging scroll 2. It is. In other words, equation (2) indicates that the value of the ratio of the eccentricity of the second swinging scroll 5 to the eccentricity of the first swinging scroll 2 is 0.95 or more and 1.05 or less, and the first swinging scroll This shows that the amount of eccentricity of No. 2 and the amount of eccentricity of the first orbiting scroll 2 are almost the same.

FIG. 9 is a schematic diagram showing the positional relationship between the two swinging scrolls and the balancer 31 of the two-stage scroll compressor 100 according to the third embodiment.

Here, in the two-stage scroll compressor 100, in order to eliminate the unbalance caused by the two oscillating scrolls, the balancer 31 must be arranged so as to satisfy the following formula (3) from the balance of static balance and dynamic balance. Bye. As shown in FIG. 9, the height from the center of gravity C of the second oscillating scroll 5 to the center of gravity F of the balancer 31 is defined as Lb, and the center of gravity C of the second oscillating scroll 5 is defined as Lb. The height of the first swinging scroll 2 to the center of gravity position A when used as a reference is defined as Lorb1.

Lb=Lorb1/(α+1) (3)

Here, α is the ratio of the product of the mass and the radius of revolution of each of the two oscillating scrolls, as shown by the following equation (4).

α=(Morb2×R2)/(Morb1×R1) (4)

In the third embodiment, 0.95≦(Morb2×R2/Morb1×R1)≦1.05, and if Morb1×R1=Morb2×R2, α=1 in equation (4). Therefore, equation (3) becomes Lb=Lorb1/2. In other words, in the two-stage scroll compressor 100, in order to eliminate the unbalance caused by the two oscillating scrolls, the balancer 31 must be moved so that the center of gravity F of the balancer 31 is the center of the center of gravity of the two oscillating scrolls. Just place it. Therefore, in the third embodiment, it is possible to eliminate the imbalance caused by the two swinging scrolls without performing complicated balance design.

(Effects of Embodiment 3)
In the two-stage scroll compressor 100 according to the third embodiment, the mass of the first orbiting scroll 2 of the first compression mechanism section 35 is Morb1, the mass of the second orbiting scroll 5 of the second compression mechanism section 36 is Morb2, When the revolution radius of the first oscillating scroll 2 of the first compression mechanism section 35 is R1, and the revolution radius of the second oscillating scroll 5 of the second compression mechanism section 36 is R2, the two oscillating scrolls are 0. .95≦(Morb2×R2/Morb1×R1)≦1.05.

According to the two-stage scroll compressor 100 according to the third embodiment, the two swinging scrolls are configured to satisfy 0.95≦(Morb2×R2/Morb1×R1)≦1.05. Therefore, in the two-stage scroll compressor 100, in order to eliminate the imbalance caused by the two oscillating scrolls, the balancer 31 is arranged so that the center of gravity F of the balancer 31 is the center of the center of gravity of the two oscillating scrolls. do it. As a result, it is possible to eliminate the imbalance caused by the two swinging scrolls without performing complicated balance design.

Embodiment 4.
Embodiment 4 will be described below, but the description of parts that overlap with Embodiments 1 to 3 will be omitted, and the same or corresponding parts as in Embodiments 1 to 3 will be given the same reference numerals.

In the two-stage scroll compressor 100 according to the fourth embodiment, the mass of the first orbiting scroll 2 is Morb1, the revolution radius of the first orbiting scroll 2 is R1, the mass of the second orbiting scroll 5 is Morb2, and the mass of the second orbiting scroll 5 is Morb2. When the revolution radius of the swinging scroll 5 is R2, the two swinging scrolls are configured to satisfy the following equation (5).

2≦(Morb2×R2)/(Morb1×R1)≦3 (5)

Here, if the product of the mass of the part and the radius of revolution is defined as the amount of eccentricity, then Morb1×R1 is the amount of eccentricity of the first swinging scroll 2, and Morb2×R2 is the amount of eccentricity of the first swinging scroll 2. It is. In other words, equation (5) indicates that the ratio of the eccentricity of the second swinging scroll 5 to the eccentricity of the first swinging scroll 2 is 2 or more and 3 or less.

In the two-stage scroll compressor 100, in order to eliminate the unbalance caused by the two oscillating scrolls, the balancer must be adjusted so as to satisfy the equation (3) explained in the third embodiment from the balance between the static balance and the dynamic balance. 31 may be placed. By arranging the balancer 31 so as to satisfy equation (3), it is possible to eliminate the imbalance caused by the two swinging scrolls.

FIG. 10 is a sectional view of a two-stage scroll compressor 100 according to Embodiment 4.
When the two swinging scrolls are configured to satisfy equation (5) and the balancer 31 is arranged so as to satisfy equation (3), as shown in FIG. It is arranged closer to the second swinging scroll 5 than the scroll 2. Therefore, a large space is formed above the balancer 31, so that, for example, the drive mechanism section 37 can be placed in the large space, and the space inside the closed container 11 can be used effectively.

Note that in the two-stage scroll compressor 100 according to the fourth embodiment, the two swinging scrolls may be configured to satisfy the following equation (5)' instead of the equation (5).

2≦(Morb1×R1)/(Morb2×R2)≦3
...(5)'

When the two oscillating scrolls are configured to satisfy equation (5)', and the balancer 31 is arranged so as to satisfy equation (3), the balancer 31 is configured to have a higher priority than the second oscillating scroll 5. It is arranged near the swinging scroll 2. Therefore, a large space is formed below the balancer 31, so that, for example, the drive mechanism section 37 can be placed in the large space, and the space inside the closed container 11 can be used effectively.

(Effects of Embodiment 4)
In the two-stage scroll compressor 100 according to the fourth embodiment, the mass of the first orbiting scroll 2 of the first compression mechanism section 35 is Morb1, the mass of the second orbiting scroll 5 of the second compression mechanism section 36 is Morb2, When the revolution radius of the first oscillating scroll 2 of the first compression mechanism section 35 is R1, and the revolution radius of the second oscillating scroll 5 of the second compression mechanism section 36 is R2, the two oscillating scrolls are 2 It is configured to satisfy ≦(Morb1×R1)/(Morb2×R2)≦3, or 2≦(Morb2×R2)/(Morb1×R1)≦3.

According to the two-stage scroll compressor 100 according to the fourth embodiment, the two oscillating scrolls satisfy 2≦(Morb1×R1)/(Morb2×R2)≦3, or 2≦(Morb2×R2)/( Morb1×R1)≦3. Therefore, in the two-stage scroll compressor 100, the balancer 31 is placed closer to one of the two oscillating scrolls in order to eliminate the imbalance caused by the two oscillating scrolls. As a result, a large space is formed above or below the balancer 31, and the space within the closed container 11 can be used effectively.

In the two-stage scroll compressor 100 according to the fourth embodiment, the height of the second compression mechanism section 36 to the center of gravity of the balancer 31 with respect to the center of gravity of the second swinging scroll 5 is Lb, When the height of the first compression mechanism section 35 to the center of gravity position of the first oscillating scroll 2 with respect to the center of gravity position of the second oscillating scroll 5 of the second compression mechanism section 36 is Lorb1, 2 The balancer 31 is arranged so that two oscillating scrolls satisfy 2≦(Morb1×R1)/(Morb2×R2)≦3 and Lb>Lorb1/2, or two oscillating scrolls The balancer 31 is arranged so that 2≦(Morb2×R2)/(Morb1×R1)≦3 and Lb<Lorb1/2 are satisfied.

According to the two-stage scroll compressor 100 according to the fourth embodiment, the two swinging scrolls satisfy 2≦(Morb1×R1)/(Morb2×R2)≦3 and satisfy Lb>Lorb1/2. The balancer 31 is arranged so that the two swing scrolls satisfy 2≦(Morb2×R2)/(Morb1×R1)≦3 and Lb<Lorb1/2. is located. That is, in the two-stage scroll compressor 100, the position where the balancer 31 is disposed in order to eliminate the imbalance caused by the two swinging scrolls is closer to one of the two swinging scrolls. As a result, a large space is formed above or below the balancer 31, and the space within the closed container 11 can be used effectively.

Embodiment 5.
Embodiment 5 will be described below, but the description of parts that overlap with Embodiments 1 to 4 will be omitted, and the same or corresponding parts as in Embodiments 1 to 4 will be given the same reference numerals.

In the two-stage scroll compressor 100 according to the fifth embodiment, the first oscillating scroll 2 is made of an aluminum material such as aluminum, and the second oscillating scroll 5 is made of a cast iron material such as spheroidal graphite cast iron. has been done.

Comparing the pressures of the fluid in the two compression chambers, we find that the pressure in the first compression chamber 12, which increases from low pressure to intermediate pressure, is higher than that in the second compression chamber 13, which increases from intermediate pressure to high pressure. is small compared to the pressure of Therefore, the strength required for the first orbiting scroll 2 is generally lower than the strength required for the second orbiting scroll 5. Therefore, for the first oscillating scroll 2, an aluminum-based material that has lower strength but also lower density than cast iron-based materials can be used.

In the two-stage scroll compressor 100 according to the fifth embodiment, the mass of the balancer 31 is Mb, the revolution radius of the center of gravity of the balancer 31 is Rb, the mass of the first swinging scroll 2 is Morb1, and the revolution of the first swinging scroll 2 When the radius is R1, the mass of the second swinging scroll 5 is Morb2, and the revolution radius of the second swinging scroll 5 is R2, the two swinging scrolls are configured to satisfy the following formula (6). There is.

Mb x Rb = Morb1 x R1 + Morb2 x R2 (6)

Here, regarding the first oscillating scroll 2, a case where it is made of a cast iron material and a case where it is made of an aluminum material will be compared with the same shape and the same revolution radius. At this time, the value of Morb1 is smaller when the structure is made of an aluminum material, which has a lower density, than when it is made from a cast iron material. Therefore, from equation (7), the mass of the balancer 31, the orbital radius of the center of gravity of the balancer 31, or both can be reduced.

Note that the first oscillating scroll 2 may be made of a cast iron material, and the second oscillating scroll 5 may be made of an aluminum material.

(Effects of Embodiment 5)
As described above, in the two-stage scroll compressor 100 according to the fifth embodiment, one of the two oscillating scrolls is made of an aluminum material, and the other is made of a cast iron material.

According to the two-stage scroll compressor 100 according to the fifth embodiment, one of the two oscillating scrolls is made of an aluminum material, and the other is made of a cast iron material. As a result, the mass of the balancer 31, the orbital radius of the center of gravity of the balancer 31, or both can be reduced, reducing the cost of materials used for the balancer 31 and expanding the space inside the closed container 11. Can be done.

1 First fixed scroll, 1a First discharge port, 1b First fixed spiral body, 1c First fixed base plate, 1d Sub port, 2 First swinging scroll, 2b First swinging scroll, 2c First swinging table Plate, 2d First swing bearing section, 2e First swing keyway, 3 First frame, 3a Bearing section, 3b Thrust bearing section, 3c Through hole, 3e First frame keyway, 4 Second fixed scroll, 4a Second discharge port, 4b Second fixed spiral body, 4c Second fixed base plate, 4e Through hole, 5 Second swing scroll, 5b Second swing scroll body, 5c Second swing base plate, 5d Second swing body Dynamic bearing section, 5e Second swing keyway, 6 Second frame, 6a Bearing section, 6b Channel, 6c Second suction port, 6d Through hole, 6e Second frame keyway, 7 Crankshaft, 7a First eccentricity part, 7b second eccentric part, 8 suction pipe, 9 discharge pipe, 10 injection pipe, 11 closed container, 12 first compression chamber, 13 second compression chamber, 14 first valve holder, 15 first valve, 16 second Valve holder, 17 second valve, 18 rotor, 19 stator, 20 oil reservoir, 21 oil pump, 22 low pressure space, 23 intermediate pressure space, 24 high pressure space, 25 first Oldham ring, 25a ring part, 25b first Oldham key, 26 Second Oldham ring, 26a Ring part, 26b Second Oldham key, 28 Subport valve holder, 29 Subport valve, 30 Chamber, 31 Balancer, 35 First compression mechanism part, 36 Second compression mechanism part, 37 Drive mechanism part, 100 Two-stage scroll compressor.

Claims (3)

an airtight container forming the outer shell;
a drive mechanism section that is arranged in the sealed container and serves as a drive source;
two compression mechanisms disposed above and below the drive mechanism section, each having a compression chamber formed by combining a fixed scroll fixed in the closed container and an oscillating scroll driven by the drive mechanism section; Department and
a crankshaft that transmits the driving force of the drive mechanism section to the two swing scrolls;
a balancer that is provided on the crankshaft and cancels out the unbalance caused by the two swinging scrolls;
two Oldham rings that prevent rotation of each of the oscillating scrolls,
The two rocking scrolls are eccentric in the same direction with respect to the central axis of the crankshaft,
The airtight container is
a low-pressure space into which fluid is sucked by one of the two compression mechanism parts; an intermediate-pressure space into which the fluid compressed by one of the two compression mechanism parts is discharged; and one of the two compression mechanism parts. It has three internal spaces, the other of which is a high pressure space from which the compressed fluid is discharged,
The two compression mechanism parts are
a first compression mechanism unit that compresses the fluid taken in from the low pressure space and discharges it into the intermediate pressure space;
a second compression mechanism unit that compresses the fluid sucked from the intermediate pressure space and discharges it into the high pressure space;
The two Oldham rings are configured such that their simple harmonic directions are orthogonal to each other,
The mass of the Oldham ring of the first compression mechanism section is Mold1, the mass of the Oldham ring of the second compression mechanism section is Mold2, the revolution radius of the orbiting scroll of the first compression mechanism section is R1, and the second When the revolution radius of the oscillating scroll of the compression mechanism section is R2,
The two Oldham rings are
It is configured to satisfy 0.95≦(Mold2×R2/Mold1×R1)≦1.05.
Two-stage scroll compressor. an airtight container forming the outer shell;
a drive mechanism section that is arranged in the sealed container and serves as a drive source;
two compression mechanisms disposed above and below the drive mechanism section, each having a compression chamber formed by combining a fixed scroll fixed in the closed container and an oscillating scroll driven by the drive mechanism section; Department and
a crankshaft that transmits the driving force of the drive mechanism section to the two swing scrolls;
a balancer that is provided on the crankshaft and cancels out the unbalance caused by the two swinging scrolls,
The two rocking scrolls are eccentric in the same direction with respect to the central axis of the crankshaft,
The balancer is
eccentric in a direction opposite to the eccentric direction of the two oscillating scrolls with respect to the central axis of the crankshaft ;
The airtight container is
a low-pressure space into which fluid is sucked by one of the two compression mechanism parts; an intermediate-pressure space into which the fluid compressed by one of the two compression mechanism parts is discharged; and one of the two compression mechanism parts. It has three internal spaces, the other of which is a high pressure space from which the compressed fluid is discharged,
The two compression mechanism parts are
a first compression mechanism unit that compresses the fluid taken in from the low pressure space and discharges it into the intermediate pressure space;
a second compression mechanism unit that compresses the fluid sucked from the intermediate pressure space and discharges it into the high pressure space;
Lb is the height to the center of gravity of the balancer when the center of gravity of the swinging scroll of the second compression mechanism is referenced, and Lb is the height of the center of gravity of the swinging scroll of the second compression mechanism. When the height to the center of gravity of the swinging scroll of the first compression mechanism section is Lorb1, the mass of the swinging scroll of the first compression mechanism section is Morb1, and the swinging scroll of the second compression mechanism section is When the mass of is Morb2, the radius of revolution of the oscillating scroll of the first compression mechanism section is R1, and the radius of revolution of the oscillating scroll of the second compression mechanism section is R2,
The balancer is arranged such that the two swinging scrolls satisfy 2≦(Morb1×R1)/(Morb2×R2)≦3 and Lb>Lorb1/2, or
The balancer is arranged such that the two swinging scrolls satisfy 2≦(Morb2×R2)/(Morb1×R1)≦3 and satisfy Lb<Lorb1/2.
Two- stage scroll compressor. The two-stage scroll compressor according to claim 2 , wherein one of the two swinging scrolls is made of an aluminum material and the other is made of a cast iron material.

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