Scroll compressor

Abstract

This scroll compressor includes a compression mechanism part and a rotary shaft. In the compression mechanism part: a compression chamber is formed for compressing a refrigerant by a fixed spiral body and an oscillating spiral body engaging with each other; the base circle center of the oscillating spiral body of an oscillating scroll is offset in the winding start direction of the oscillating spiral body with respect to the center of an eccentric shaft part; the base circle center of the fixed spiral body of the fixed scroll is offset in the winding start direction of the fixed spiral body with respect to the center of the main shaft part; and among the points at which the base circle radius is the minimum in the oscillating spiral body and the fixed spiral body, the oblateness from the point (φrad) closest to a winding end to a point (φ-πrad) is set to be smaller than the oblateness from the point (φ-πrad) to a point (φ-2πrad).

Description

Scroll Compressor

[0001] The present disclosure relates to scroll compressors.

[0002] A scroll compressor used in an air conditioner, a refrigerator, or the like includes a compression mechanism that compresses a refrigerant in a compression chamber formed by combining a fixed scroll and an orbiting scroll, and a container that houses the compression mechanism. The fixed scroll and the orbiting scroll each have a configuration in which a scroll body is formed on a base plate, and the scroll bodies are meshed with each other to form a compression chamber. When the orbiting scroll is caused to oscillate, the compression chamber moves while reducing its volume, and the refrigerant is sucked into and compressed in the compression chamber.

[0003] Among these types of scroll compressors, a through-shaft scroll compressor in which the rotating shaft passes through the volute body of the orbiting scroll is known in order to stabilize the behavior of the orbiting scroll, thereby reducing losses due to internal leakage in the compression chamber and improving reliability. For this type of through-shaft scroll compressor, there is a technology for supporting the horizontal gas load of the compression mechanism within the plane of the orbiting bearing (see, for example, Patent Document 1).

[0004] Japanese Patent Application Publication No. 08-200250

[0005] However, in a configuration such as the compressor of Patent Document 1, the shape of the spiral bodies of the fixed scroll and the orbiting scroll does not allow the installation space of the spiral bodies within the compressor to be fully utilized for compression, resulting in a problem of insufficient suction volume or built-in volume ratio of the compressor.

[0006] The present disclosure has been made in consideration of the above points, and has an object to provide a scroll compressor in which the shapes of the scroll bodies of the fixed scroll and the swinging scroll are optimized to fit the installation space for the scroll bodies within the compressor, thereby improving the suction volume and built-in volume ratio of the compressor.

[0007] The scroll compressor according to the present disclosure comprises a compression mechanism section having at least one oscillating scroll with an oscillating scroll formed on an oscillating base plate, and at least one fixed scroll with a fixed scroll formed on a fixed base plate provided at a position opposite the oscillating scroll, and a rotating shaft penetrating the compression mechanism section and having a main shaft section and an eccentric shaft section that is eccentric with respect to the main shaft section and fixed to the oscillating scroll, and in the compression mechanism section, a compression chamber that compresses a refrigerant is formed by meshing the fixed scroll and the oscillating scroll, The base circle center of the oscillating spiral body of the crawler is offset in the direction of the start of winding of the oscillating spiral body from the center of the eccentric shaft portion as a reference, and the base circle center of the fixed spiral body of the fixed scroll is offset in the direction of the start of winding of the fixed spiral body from the center of the main shaft portion as a reference, and the flattening ratio from the point (φrad) closest to the end of winding to point (φ-πrad) among the points where the base circle radius is minimum in the oscillating spiral body and the fixed spiral body is set to be smaller than the flattening ratio from point (φ-πrad) to point (φ-2πrad).

[0008] The scroll compressor according to the present disclosure includes a compression mechanism having at least one oscillating scroll with an oscillating scroll formed on an oscillating base plate, and at least one fixed scroll with a fixed scroll formed on a fixed base plate provided at a position opposite the oscillating scroll, and a rotating shaft penetrating the compression mechanism and having a main shaft portion and an eccentric shaft portion eccentric with respect to the main shaft portion and fixed to the oscillating scroll, and in the compression mechanism, a compression chamber for compressing a refrigerant is formed by meshing the fixed scroll and the oscillating scroll. The center of the base circle of the oscillating spiral of the fixed scroll is offset in the direction of the start of winding of the oscillating spiral from the center of the eccentric shaft portion as a reference, and the center of the base circle of the fixed spiral of the fixed scroll is offset in the direction of the start of winding of the fixed spiral from the center of the main shaft portion as a reference, and the maximum value of the tooth thickness from the point (φ rad) closest to the end of winding to point (φ-π rad) among the points where the base circle radius is minimum in the oscillating spiral and fixed spiral is set smaller than the maximum value of the tooth thickness from point (φ-π rad) to point (φ-2π rad).

[0009] According to the present disclosure, in a scroll compressor, the base circle center of the orbiting scroll's orbiting scroll is offset in the direction of the start of winding of the orbiting scroll from the center of the eccentric shaft portion. Also, in the scroll compressor, the base circle center of the fixed scroll's fixed scroll is offset in the direction of the start of winding of the fixed scroll from the center of the main shaft portion. Also, in the scroll compressor, among the points where the base circle radii of the orbiting scroll and the fixed scroll are smallest, the flattening ratio from the point (φ rad) closest to the end of winding to point (φ-π rad) is set smaller than the flattening ratio from point (φ-π rad) to point (φ-2π rad). Alternatively, the maximum value of the tooth thickness from the point (φ rad) closest to the end of winding to point (φ-π rad) is set smaller than the maximum value of the tooth thickness from point (φ-π rad) to point (φ-2π rad). By having the above-described configuration, the scroll compressor can optimize the shapes of the scroll bodies of the fixed scroll and the orbiting scroll relative to the installation space for the scroll bodies within the compressor, thereby improving the suction volume and built-in volume ratio of the compressor.

[0010] Fig. 1 is a schematic vertical cross-sectional view of the overall configuration of a scroll compressor according to embodiment 1. Fig. 2 is a view showing a compression process in operation during one rotation of an orbiting scroll in the scroll compressor according to embodiment 1. Fig. 3 is a view showing the shape of the orbiting scroll in the scroll compressor according to embodiment 1. Fig. 4 is a view showing the relationship between the flattening ratio and the extension angle of the orbiting scroll in the scroll compressor according to embodiment 1. Fig. 5 is a view showing the relationship between the base circle radius and the tooth thickness of the orbiting scroll and the extension angle in the scroll compressor according to embodiment 1. Fig. 6 is a schematic vertical cross-sectional view of the overall configuration of a scroll compressor according to embodiment 2. Fig. 7 is a view showing the shape of the back surface of a first fixed scroll of the scroll compressor according to embodiment 2.

[0011] Hereinafter, a scroll compressor according to an embodiment will be described with reference to the drawings. In the following drawings, including FIG. 1, components with the same reference numerals are the same or equivalent, and are common throughout the embodiments described below. The configurations of the components shown throughout the specification are merely examples, and the present invention is not limited to the configurations described in the specification.

[0012] Embodiment 1 Fig. 1 is a schematic vertical cross-sectional view of the overall configuration of a scroll compressor 150 according to Embodiment 1. The scroll compressor 150 is a through-shaft scroll compressor.

[0013] The scroll compressor 150 according to the first embodiment includes a compression mechanism 30 , a rotating shaft 3 , a rotation prevention mechanism 5 , and an electric mechanism 6 .

[0014] More specifically, the scroll compressor 150 according to the first embodiment includes a compression mechanism 30 including an orbiting scroll 1 and a fixed scroll 2, an electric mechanism 6 that drives the compression mechanism 30 via a rotating shaft 3, and other components. The scroll compressor 150 has a configuration in which these components are housed inside a sealed container 100 that forms an outer shell. Within the sealed container 100, the compression mechanism 30 is located at a lower position, and the electric mechanism 6 is located above the compression mechanism 30.

[0015] A frame 4 is also housed inside the sealed container 100, between the orbiting scroll 1 of the compression mechanism 30 and the electric mechanism 6. The frame 4 is fixed to the inner peripheral surface of the sealed container 100 by shrink fitting, welding, or the like. Reamed holes (not shown) are formed in the frame 4 and the fixed scroll 2. The frame 4 is connected to the fixed scroll 2 by reamer pins (not shown) inserted into the reamed holes of the frame 4 and the fixed scroll 2. The frame 4 is fastened to the fixed scroll 2 by fixing parts such as bolts (not shown).

[0016] An oil supply path 200 is formed inside the rotating shaft 3, and a stirrer 10 is attached inside the oil supply path 200. The lower end of the rotating shaft 3 is placed in refrigeration oil stored in an oil reservoir 99 at the bottom of the sealed container 100. The refrigeration oil in the oil supply path 200 is subjected to centrifugal force by the stirrer 10 rotating together with the rotating shaft 3, and is supplied to each sliding part such as bearings 7, 8, and 9, which will be described later, via each bearing and a horizontal hole (not shown) in the rotating shaft 3 connected to the oil supply path 200. In this embodiment, the oil supply method is centrifugal oil supply, but is not limited to this, and pump oil supply using a positive displacement pump or the like may also be used.

[0017] The sealed container 100 is provided with a suction pipe 50 for drawing in the refrigerant and a discharge pipe 51 for discharging the refrigerant.

[0018] The compression mechanism 30 includes an orbiting scroll 1 and a fixed scroll 2. More specifically, the compression mechanism 30 includes at least one orbiting scroll 1 having an orbiting scroll 1b formed on an orbiting base plate 1a, and at least one fixed scroll 2 having a fixed scroll 2b formed on a fixed base plate 2a provided in a position opposite the orbiting scroll 1b. The compression mechanism 30, which includes the orbiting scroll 1 and the fixed scroll 2, has the function of compressing refrigerant sucked through the suction pipe 50 and discharging the compressed refrigerant into a first space 401 formed below the compression mechanism 30.

[0019] The orbiting scroll 1 is disposed above the fixed scroll 2 and is supported so as to be freely oscillating on an eccentric shaft portion 3b (described later) of the rotary shaft 3. The fixed scroll 2 is fixed to the inner peripheral surface of the sealed container 100.

[0020] The orbiting scroll 1 includes an orbiting base plate 1a and an orbiting spiral body 1b, which is a spiral protrusion formed on one surface of the orbiting base plate 1a. The fixed scroll 2 includes a fixed base plate 2a, a fixed spiral body 2b, which is a spiral protrusion formed on one surface of the fixed base plate 2a, and a fixed boss portion 2m.

[0021] The orbiting scroll 1 and the fixed scroll 2 are disposed in the sealed container 100 with the orbiting scroll 1b and the fixed scroll 2b meshing with each other. A compression chamber 71 is formed between the orbiting scroll 1b and the fixed scroll 2b, and the volume of the compression chamber 71 decreases from the outer side to the inner side in the radial direction as the rotating shaft 3 rotates. That is, in the compression mechanism 30 of the scroll compressor 150, the fixed scroll 2b and the orbiting scroll 1b mesh with each other to form the compression chamber 71 that compresses the refrigerant.

[0022] A discharge flow path 301 is formed in the fixed base plate 2a of the fixed scroll 2 to discharge the refrigerant compressed in the compression chamber 71 into the first space 401. A discharge valve 13 that opens and closes the discharge flow path 301 is provided in the discharge flow path 301.

[0023] A refrigerant flow path 302 is formed in the frame 4 and the fixed scroll 2, connecting a first space 401 located below the compression mechanism 30 with a second space 402 located above the compression mechanism 30. The refrigerant flow path 302 is a hole that penetrates the compression mechanism 30 in the axial direction of the rotating shaft 3, and is a refrigerant flow path that connects the first space 401 with the second space 402. The second space 402 is a space between the compression mechanism 30 and the electric mechanism 6 in the axial direction of the rotating shaft 3.

[0024] An anti-rotation mechanism 5 is disposed on the oscillating base plate 1a to prevent rotation of the oscillating scroll 1 during its orbital motion. The anti-rotation mechanism 5 connects the oscillating scroll 1 to the frame 4. An Oldham ring is generally used as the anti-rotation mechanism 5, but it is not limited to this. The detailed structures of the oscillating scroll 1 and the fixed scroll 2 will be described later.

[0025] The electric mechanism 6 supplies a rotational driving force to the rotating shaft 3 and includes an electric motor stator 6a and an electric motor rotor 6b. The electric mechanism 6 has the electric motor stator 6a and the electric motor rotor 6b to which the main shaft 3a is fixed, and drives the rotating shaft 3.

[0026] The motor stator 6a is connected by lead wires (not shown) to glass terminals (not shown) on the top or side of the sealed container 100 to obtain electric power from the outside. The motor rotor 6b is fixed to the rotating shaft 3 by shrink fitting or the like. In order to balance the entire rotating system of the scroll compressor 150, a first balance weight 11 is fixed to the rotating shaft 3, and a second balance weight 12 is fixed to the motor rotor 6b. These balance weights are fixed by shrink fitting, caulking or the like. The arrangement of the balance weights is not limited to this and may be freely determined.

[0027] The rotating shaft 3 has an upper main shaft portion 3a, an eccentric shaft portion 3b in the middle, and a lower counter shaft portion 3c. The eccentric shaft portion 3b is eccentric with respect to the axial centers of the main shaft portion 3a and the counter shaft portion 3c of the rotating shaft 3. The eccentric shaft portion 3b is eccentric with respect to the main axial center of the rotating shaft 3. The rotating shaft 3 passes through the compression mechanism portion 30 and has the main shaft portion 3a and the eccentric shaft portion 3b that is eccentric with respect to the main shaft portion 3a and is fixed to the orbiting scroll 1. The eccentric shaft portion 3b is fitted to the orbiting scroll 1 via a bearing 8. The rotation of the rotating shaft 3 causes the orbiting scroll 1 to perform an orbiting motion, and the eccentric shaft portion 3b slides against the bearing 8 via an oil film of refrigerant oil.

[0028] The main shaft portion 3a is fitted to the frame 4 via a bearing 7 arranged in the frame 4, and slides against the bearing 7 via an oil film of refrigerant oil. The counter shaft portion 3c is fitted to the fixed scroll 2 via a bearing 9 arranged in the fixed scroll 2, and slides against the bearing 9 via an oil film of refrigerant oil. The axis of the main shaft portion 3a of the rotating shaft 3 and the axis of the counter shaft portion 3c are aligned.

[0029] Here, the space within the sealed container 100 is defined as follows. Within the internal space of the sealed container 100, the space below the compression mechanism 30 is referred to as a first space 401. Furthermore, the space between the compression mechanism 30 and the electric mechanism 6 is referred to as a second space 402. Furthermore, the space above the electric mechanism 6, which is in communication with the discharge pipe 51, is referred to as a third space 403. As described above, the first space 401 and the second space 402 are in communication with each other via the refrigerant flow path 302. The second space 402 and the third space 403 are in communication with each other, for example, via a through-hole (not shown) formed in the motor rotor 6b or a gap between the motor stator 6a and the motor rotor 6b.

[0030] Fig. 2 is a diagram showing a compression process during one rotation of the orbiting scroll 1 in the scroll compressor 150 according to the first embodiment. Next, the operation of the compression mechanism 30 including the orbiting scroll 1 and the fixed scroll 2 will be described with reference to Fig. 2. Fig. 2 shows the orbiting scroll body 1b of the orbiting scroll 1 and the fixed scroll body 2b of the fixed scroll 2 in the A-A cross section in Fig. 1 of the scroll compressor 150 according to the first embodiment.

[0031] 2A is a compression process diagram showing operation at a rotational phase of 0° during one rotation of the orbiting scroll 1 of the scroll compressor 150 according to the first embodiment. 2B is a compression process diagram showing operation at a rotational phase of 90° during one rotation of the orbiting scroll 1 of the scroll compressor 150 according to the first embodiment.

[0032] 2C is a compression process diagram showing operation at a rotational phase of 180 degrees during one rotation of the orbiting scroll 1 of the orbiting scroll 1 in the scroll compressor 150 according to the first embodiment. 2D is a compression process diagram showing operation at a rotational phase of 270 degrees during one rotation of the orbiting scroll 1 of the scroll compressor 150 according to the first embodiment.

[0033] The rotational phase is based on the point when compression begins in the compression chamber 71 formed by the inward surface of the fixed scroll 2b and the outward surface of the oscillating scroll 1b. 2A to 2D in Figure 2 show the state in which the oscillating scroll 1b oscillates in the order of rotational phases 0°, 90°, 180°, and 270°, respectively.

[0034] When electricity is applied to a glass terminal (not shown) provided on the sealed container 100, the rotary shaft 3 of the scroll compressor 150 is rotated by the motor rotor 6b. Then, in the scroll compressor 150, the rotational force is transmitted to the bearing 8 via the eccentric shaft portion 3b of the rotary shaft 3, and the rotational force is transmitted from the bearing 8 to the orbiting scroll 1, causing the orbiting scroll 1 to perform an orbiting motion. The gas refrigerant sucked into the sealed container 100 from the suction pipe 50 is taken into the compression mechanism 30, which includes the orbiting scroll 1 and the fixed scroll 2.

[0035] 2A shows a state in which the compression chamber 71 formed by the inward surface of the fixed scroll 2b and the outward surface of the oscillating scroll 1b is closed and refrigerant suction is complete. Focusing on the configuration of the compression chamber 71 from 2A to 2D in FIG. 2, the compression chamber 71 reduces in volume as it moves from the outer periphery toward the center in accordance with the oscillating motion of the oscillating scroll 1. The gas refrigerant in the compression chamber 71 is compressed as the volume of the compression chamber 71 decreases.

[0036] As shown in Fig. 2, the compression chamber 71 reduces its volume in the order of 2A, 2B, 2C, and 2D as the rotary shaft 3 rotates. As shown in Fig. 2, 2A to 2D, the compression chamber 71 communicates with the discharge flow path 301 near the center of the scroll, and the compressed refrigerant is discharged into the first space 401 via the discharge valve 13.

[0037] As shown in FIG. 1 , in the scroll compressor 150, a back pressure chamber 73 is formed between the orbiting scroll 1 and the frame 4. That is, in the scroll compressor 150, the back pressure chamber 73, which communicates with the compression chamber 71, is formed on the back surface of one of the fixed scrolls. The back pressure chamber 73 is sealed in the radial direction centered on the rotary shaft 3 by an annular sealing material 14. The back pressure chamber 73 is connected to the compression chamber 71 by a flow path (not shown), and the pressure of the compression chamber 71 is bled to the back pressure chamber 73. In the scroll compressor 150, the pressure of the back pressure chamber 73 presses the orbiting scroll 1 downward in the axial direction, sealing the tooth tips of the orbiting scroll 1 b and the fixed scroll 2 b.

[0038] Next, the flow of refrigerant will be described. The gas refrigerant discharged from the scroll compressor 150 returns to the scroll compressor 150 via a refrigeration cycle equipped with a condenser, an expansion valve, an evaporator, etc. The gas refrigerant returning to the scroll compressor 150 flows into the sealed container 100 through the suction pipe 50. The low-pressure refrigerant that flows into the sealed container 100 from the suction pipe 50 is taken into the compression mechanism 30 equipped with the swinging scroll 1 and the fixed scroll 2, and is drawn into the compression chamber 71 as the swinging motion of the swinging scroll 1b occurs.

[0039] The gas refrigerant sucked into the compression chamber 71 is pressurized from low pressure to high pressure due to a geometric change in the volume of the compression chamber 71 caused by the movement of the oscillating scroll 1b. The high-pressure gas refrigerant then pushes open the discharge valve 13 and is then discharged into the first space 401. The gas refrigerant discharged into the first space 401 flows into the second space 402 via the refrigerant flow path 302. The gas refrigerant that has flowed into the second space 402 then passes through gaps between the motor stator 6a and the motor rotor 6b and flows into a third space 403 above the electric mechanism 6 located at the top of the sealed container 100. The gas refrigerant that has flowed into the third space 403 is discharged from the discharge pipe 51 to the outside of the scroll compressor 150 as high-pressure refrigerant.

[0040] FIG. 3 is a diagram showing the shape of the orbiting scroll 1 in the scroll compressor 150 according to the first embodiment. FIG. 4 is a diagram showing the relationship between the flattening ratio and the extension angle of the orbiting scroll 1 in the scroll compressor 150 according to the first embodiment. FIG. 5 is a diagram showing the relationship between the base circle radius and the tooth thickness of the orbiting scroll 1 in the scroll compressor 150 according to the first embodiment and the extension angle. In FIG. 5, the dotted line indicates the tooth thickness on the right side of the vertical axis, and the solid line indicates the base circle radius on the left side of the vertical axis. Furthermore, the solid and dotted arrows in FIG. 5 indicate which axis to view. Next, the shapes of the orbiting scroll 1 and the fixed scroll 2, which are characteristic parts of the first embodiment, will be described with reference to FIGS. 3, 4, and 5.

[0041] The curves of the outward surfaces of the oscillating spiral body 1b and the fixed spiral body 2b utilize the involute curves of circles shown in the following equations (1) and (2). Here, θ in equations (1) and (2) is the involution angle, and ζ is the angle that defines the rotation of the spirals of the oscillating spiral body 1b and the fixed spiral body 2b. Also, a(θ) is the base circle radius and is given as a function of the involution angle θ. a(θ) is a function shown in the following equation (3). a ｍｉｎ is the minimum value of the base circle radius, and ξ is the angle that defines the flattening direction of the swivel spiral 1b and the fixed spiral 2b. ｍｉｎ is determined from the combination of the base radius and the eccentricity to obtain a value that maximizes the intake volume while ensuring the required built-in volume ratio. α is the oblateness, which is a value that defines the degree of oblateness of the swivel scroll 1b and the fixed scroll 2b. The larger α is, the flatter the swivel scroll 1b and the fixed scroll 2b will be. x = a(θ) (cos(θ-ζ) + θ sin(θ-ζ)) (1) y = a(θ) (sin(θ-ζ) - θ cos(θ-ζ)) (2) a(θ) = a ｍｉｎ (1 + α sin ２ (θ−ξ)) (3)

[0042] Point 1h shown in Fig. 3 indicates the start point of the inward surface of oscillating spiral 1b, and point 1i shown in Fig. 3 indicates the start point of the outward surface of oscillating spiral 1b. That is, point 1h is the start point of the inward surface of oscillating spiral 1b, and point 1i is the start point of the outward surface of oscillating spiral 1b. Point 2h shown in Fig. 3 indicates the start point of the inward surface of fixed spiral 2b, and point 2i shown in Fig. 3 indicates the start point of the outward surface of fixed spiral 2b. That is, point 2h is the start point of the inward surface of fixed spiral 2b, and point 2i is the start point of the outward surface of fixed spiral 2b. Between point 1h, the start point of the inward surface, and point 1i, the start point of the outward surface of oscillating spiral 1b, the oscillating spiral 1b is formed by a linear portion formed in a straight line, or a curved portion formed by a gentle curve with an inflection point. The fixed spiral body 2b is formed by a linear portion formed in a straight line between point 2h, which is the starting point of the inward surface, and point 2i, which is the starting point of the outward surface, or a curved portion formed by a gentle curve with an inflection point.

[0043] The end of the windings on the outward surface of oscillating spiral body 1b is the point on the outward surface of oscillating spiral body 1b that is farthest from the center of the base circle of oscillating spiral body 1b, and the end of the windings on the inward surface of oscillating spiral body 1b is the point on the inward surface of oscillating spiral body 1b that is farthest from the center of the base circle of oscillating spiral body 1b. The end of the windings on the outward surface of fixed spiral body 2b is the point on the outward surface of fixed spiral body 2b that is farthest from the center of the base circle of fixed spiral body 2b, and the end of the windings on the inward surface of fixed spiral body 2b is the point on the inward surface of fixed spiral body 2b that is farthest from the center of the base circle of fixed spiral body 2b.

[0044] Of the curves that form the compression chamber 71, the curve with a large curvature that faces outward is the inward surface, and the curve with a small curvature that faces inward is the outward surface. Strictly speaking, since the center of the spiral is connected by an arc rather than a curve defined by the formula, the outward surface is the curve defined by formulas (1) to (3) in a plan view, and the straight line portion of the curve that smoothly connects to it or the surface up to the inflection point. Also, the inward surface is the curve that forms the compression chamber 71 opposite the curve defined by formulas (1) to (3) in a plan view, and the straight line portion of the curve that smoothly connects to it or the surface up to the inflection point.

[0045] Here, the characteristics of the scroll compressor 150 according to the first embodiment will be described using the orbiting scroll 1b as an example. As shown in FIG. 3 , the center 1d of the base circle radius of the orbiting scroll 1 is offset toward the start of winding of the orbiting scroll 1b from the center 1c of the orbiting scroll 1, which is the center of the bearing of the orbiting scroll 1 and the center of the rotary shaft 3. "Offset toward the start of winding" means that, in a cross section perpendicular to the axis in FIG. 3 , when a line is drawn that passes through the center of the main shaft 3a, which is the center of the compressor, and is perpendicular to a line connecting the center of the compressor and the start of winding, the center of the base circle is closer to the start of winding than the line. Note that, for the orbiting scroll 1, the "start of winding" here refers to, for example, the midpoint of an imaginary line segment connecting point 1i, which is the start point of the outward surface of the orbiting scroll 1b, and point 1h, which is the start point of the inward surface of the orbiting scroll 1b. The center 1c of the orbiting scroll 1 is the center of the rotary shaft 3, which is the center of the eccentric shaft 3b of the rotary shaft 3.

[0046] That is, in the scroll compressor 150, the base circle center of the oscillating scroll 1's oscillating scroll 1 is offset in the direction of the start of the oscillating scroll 1's winding from the center of the eccentric shaft portion 3b (see FIG. 1). Furthermore, in the scroll compressor 150, the flattening α from point 1e (φ rad) closest to the end of the oscillating scroll 1's winding (of the points where the base circle radius is smallest) to point 1f (φ-π rad) is set smaller than the flattening α from point 1f (φ-π rad) to point 1g (φ-2π rad). While FIG. 3 shows the base circle center on the side with the smaller flattening, it may also be on the side with the larger flattening. Point 1e (φ-rad) has a larger extension angle than the end of the oscillating scroll 1b, and may be a virtual point extending the oscillating scroll 1b. Here, among the points where the base circle radius of the oscillating spiral 1b is minimum, point 1e, which is closest to the end of the spiral, will be explained using Figure 5. The base circle radius takes on a minimum value every π rad. Among these points, the point closest to the end of the spiral is the point with the largest involution angle, so in Figure 5, the rightmost point of the solid line is point 1e closest to the end of the spiral.

[0047] The flattening direction of the spirals of the oscillating spiral body 1b and the fixed spiral body 2b is a fixed value per spiral. The flattening ratio α of the spirals of the oscillating spiral body 1b and the fixed spiral body 2b is set in a stepped manner every π rad. Because the flattening ratio α of the spirals is set in a stepped manner every π rad, the value of the flattening ratio α is constant over a π rad length section. In the range from point 1e (φ rad) to point 1f (φ-π rad), distance A is the distance from the center to "φ-1 / 2π". In the range from point 1f (φ-π rad) to point 1g (φ-2π rad), distance B is the distance from the center to "φ-3 / 2π". In this case, the spiral shape is formed so that distance A and distance B are equal. When the flattening ratio is constant, distance A is longer than distance B. Therefore, when the aspect ratio is constant, there is a margin in the direction of distance A, but there is a constraint in the direction of distance B, which poses a problem that the volute size (≒ compressor output) cannot be increased. In scroll compressor 150, by changing the aspect ratio of the volute depending on the direction and making distance A and distance B equal, the shape of the volute is optimized for the installation space for the volute within the compressor, thereby improving the suction volume and built-in volume ratio of the compressor.

[0048] In other words, the rate of change in tooth thickness and the maximum value of tooth thickness from point 1e (φ rad) closest to the end of the spiral to point 1f (φ-π rad), among the points where the tooth thickness is minimal on oscillating spiral 1b, are set smaller than the rate of change in tooth thickness and the maximum value of tooth thickness from point 1f (φ-π rad) to point 1g (φ-2π rad). Here, tooth thickness is defined as the minimum distance from any point on the outward surface of oscillating spiral 1b to the inward surface.

[0049] Among the points where the base circle radius is minimum in the oscillating spiral 1b, the maximum value of the tooth thickness from point 1e (φrad) closest to the end of the winding to point 1f (φ-πrad) is set smaller than the maximum value of the tooth thickness from point 1f (φ-πrad) to point 1g (φ-2πrad).

[0050] Generally, due to the characteristics of an involute curve, the curved portion of the oscillating scroll 1b near the end of the spiral bulges outward in the radial direction. For this reason, in the conventional compression mechanism 30, the area opposite the bulging direction of the oscillating scroll 1b was wasted space that could not be used for compression. To maximize the use of the internal space of the scroll compressor 150 for compression, it is effective to make the spiral shape of the oscillating scroll 1b from point 1f to point 1g flatter than the spiral shape from point 1e to point 1f. For example, in the compression mechanism 30 shown in FIG. 3, the section at the 7 o'clock position has an aspect ratio of 0 (normal involute), and the opposite section at the 1 o'clock position has an aspect ratio of 0.145.

[0051] While the description here has focused on the oscillating scroll 1b, the same applies to the fixed scroll 2b. As shown in Fig. 3, the center 2d of the base radius of the fixed scroll 2 is offset from the center 2c of the fixed scroll 2, which is the center of the bearing of the fixed scroll 2 and the center of the rotating shaft 3, toward the start of winding of the fixed scroll 2b. Note that, in the case of the fixed scroll 2, the "start of winding" here refers to, for example, the midpoint of an imaginary line segment connecting point 2i, which is the start point of the outward surface of the fixed scroll 2b, and point 2h, which is the start point of the inward surface of the fixed scroll 2b. The center 2c of the fixed scroll 2 is the center of the rotating shaft 3, and is also the center of the main shaft portion 3a and the counter shaft portion 3c of the rotating shaft 3.

[0052] That is, in the scroll compressor 150, the center of the base circle of the fixed scroll 2b of the fixed scroll 2 is offset in the direction of the start of winding of the fixed scroll 2b from the center of the main shaft portion 3a and the counter shaft portion 3c, which are the center of the compressor. Furthermore, in the scroll compressor 150, the flattening α from point 2e (φ rad) closest to the end of the winding to point 2f (φ-π rad), among the points where the base circle radius is smallest in the fixed scroll 2b, is set to be smaller than the flattening α from point 2f (φ-π rad) to point 2g (φ-2π rad). Point 2e has a larger extension angle than the end of the winding of the fixed scroll 2b, and may be a virtual point extending the curve of the fixed scroll 2b.

[0053] In the flattened shape of the spiral, distance A is the distance from the center to "φ-1 / 2π" in the range from point 2e (φ rad) to point 2f (φ-π rad). Distance B is the distance from the center to "φ-3 / 2π" in the range from point 2f (φ-π rad) to point 2g (φ-2π rad). In this case, the spiral shape is formed so that distance A is equal to distance B. When the flattening ratio is constant, distance A is longer than distance B. Therefore, when the flattening ratio is constant, there is room in the direction of distance B, but the direction of distance A is a constraint, which poses a problem of not being able to increase the spiral size (≒ compressor output). In the scroll compressor 150, by changing the flattening ratio of the spiral body depending on the direction and making distance A equal to distance B, the shape of the spiral body is optimized for the installation space of the spiral body within the compressor, improving the suction volume and built-in volume ratio of the compressor.

[0054] In other words, the rate of change in tooth thickness and the maximum value of tooth thickness from point 2e (φ rad) closest to the end of the spiral to point 2f (φ-π rad), among the points where tooth thickness is minimal on fixed spiral body 2b, are set smaller than the rate of change in tooth thickness and the maximum value of tooth thickness from point 2f (φ-π rad) to point 2g (φ-2π rad). Here, tooth thickness is defined as the minimum distance from any point on the outward surface of fixed spiral body 2b to the inward surface.

[0055] Among the points where the base circle radius is smallest on the fixed spiral body 2b, the maximum value of the tooth thickness from point 2e (φrad) closest to the end of the spiral to point 2f (φ-πrad) is set smaller than the maximum value of the tooth thickness from point 2f (φ-πrad) to point 2g (φ-2πrad).

[0056] Generally, due to the characteristics of an involute curve, the curved portion of the fixed scroll 2b near the end of the spiral bulges outward in the radial direction. For this reason, in the conventional compression mechanism 30, the area opposite the bulging direction of the fixed scroll 2b was wasted space that could not be used for compression. To maximize the use of the internal space of the scroll compressor 150 for compression, it is effective to make the spiral shape of the fixed scroll 2b from point 2f to point 2g flatter than the spiral shape from point 2e to point 2f.

[0057] In the scroll compressor 150, the base circle center of the orbiting scroll 1b of the orbiting scroll is offset in the direction of the start of the orbiting scroll 1b from the center of the eccentric shaft portion 3b. In the scroll compressor 150, the base circle center of the fixed scroll 2b of the fixed scroll is offset in the direction of the start of the fixed scroll 2b from the center of the main shaft portion 3a. In the scroll compressor 150, the flattening ratio from the point (φ rad) closest to the end of the orbiting scroll 1b and the point (φ-π rad) where the base circle radii are minimum in the orbiting scroll 1b and the fixed scroll 2b is set to be smaller than the flattening ratio from the point (φ-π rad) to the point (φ-2π rad). The scroll compressor 150 has the above-described configuration, which allows the shapes of the scrolls of the fixed scroll 2 and the orbiting scroll 1 to be optimized for the installation space for the scrolls within the compressor, thereby improving the suction volume and built-in volume ratio of the compressor.

[0058] By adopting this configuration, the scroll compressor 150 can maximize the use of space that was previously wasted in a compressor not having the above configuration. Therefore, compared to a compressor not having the above configuration, the scroll compressor 150 can increase the suction volume of the compression mechanism 30 including the oscillating scroll 1 b and the fixed scroll 2 b, thereby improving the compressor's capacity and energy efficiency.

[0059] In the scroll compressor 150, the base circle center of the orbiting scroll 1b of the orbiting scroll is offset in the direction of the start of the orbiting scroll 1b from the center of the eccentric shaft portion 3b. In the scroll compressor 150, the base circle center of the fixed scroll 2b of the fixed scroll is offset in the direction of the start of the fixed scroll 2b from the center of the main shaft portion 3a. In the scroll compressor 150, the maximum tooth thickness from the point (φ rad) closest to the end of the winding to point (φ-π rad) of the points where the base circle radii of the orbiting scroll 1b and the fixed scroll 2b are smallest is set smaller than the maximum tooth thickness from point (φ-π rad) to point (φ-2π rad). The scroll compressor 150 has the above-described configuration, which allows the shapes of the scrolls of the fixed scroll 2 and the orbiting scroll 1 to be optimized for the installation space for the scrolls within the compressor, thereby improving the suction volume and built-in volume ratio of the compressor.

[0060] By adopting this configuration, the scroll compressor 150 can maximize the use of space that was previously wasted in a compressor not having the above configuration. Therefore, compared to a compressor not having the above configuration, the scroll compressor 150 can increase the suction volume of the compression mechanism 30 including the oscillating scroll 1 b and the fixed scroll 2 b, thereby improving the compressor's capacity and energy efficiency.

[0061] Furthermore, the point (φrad) has a larger extension angle than the end portions of the oscillating scroll 1 b and the fixed scroll 2 b, and is a virtual point formed by extending the curves of the oscillating scroll 1 b and the fixed scroll 2 b. Even with this configuration, the scroll compressor 150 can improve the suction volume and built-in volume ratio of the compressor by optimizing the shapes of the scrolls of the fixed scroll 2 and the oscillating scroll 1 to fit the installation space for the scrolls within the compressor.

[0062] Embodiment 2. Figure 6 is a schematic vertical cross-sectional view of the overall configuration of a scroll compressor 150 according to embodiment 2. Note that components having the same functions and actions as those in embodiment 1 are given the same reference numerals, and descriptions thereof will be omitted. The scroll compressor 150 according to embodiment 2 differs from embodiment 1 in the compression mechanism 30. In embodiment 2, only the characteristic features will be described, and descriptions of other parts will be omitted.

[0063] The scroll compressor 150 according to the second embodiment is characterized by the presence of two compression mechanisms 30. The first orbiting scroll 101 has a first orbiting base plate 101a and a first orbiting spiral body 101b which is a spiral protrusion formed on one surface of the first orbiting base plate 101a. The second orbiting scroll 111 has a second orbiting base plate 111a and a second orbiting spiral body 111b which is a spiral protrusion formed on one surface of the second orbiting base plate 111a.

[0064] The first fixed scroll 102 has a first fixed base plate 102a, a first fixed spiral body 102b which is a spiral protrusion formed on one surface of the first fixed base plate 102a, and a first fixed boss portion 102m. The second fixed scroll 112 has a second fixed base plate 112a, a second fixed spiral body 112b which is a spiral protrusion formed on one surface of the second fixed base plate 112a, and a second fixed boss portion 112m.

[0065] The scroll compressor 150 has a first compression mechanism 30a including a first orbiting scroll 101 and a first fixed scroll 102, and a second compression mechanism 30b including a second orbiting scroll 111 and a second fixed scroll 112. The scroll compressor 150 has a configuration in which the first compression mechanism 30a and the second compression mechanism 30b are housed inside a sealed container 100 that forms an outer shell. The first compression mechanism 30a and the second compression mechanism 30b are collectively referred to as the compression mechanism 30.

[0066] The scroll compressor 150 also includes an electric mechanism 6 that drives the compression mechanism 30 via the rotary shaft 3, and other components, all of which are housed inside the sealed container 100 that forms the outer shell. The scroll compressor 150 has a first orbiting scroll 101 and a second orbiting scroll 111 that are arranged back-to-back, with the first compression mechanism 30a disposed above the second compression mechanism 30b. That is, the scroll compressor 150 includes two orbiting scrolls and two fixed scrolls, with the two orbiting scrolls arranged back-to-back. The second fixed scroll 112 is fixed to the inner circumferential surface of the sealed container 100 by shrink fitting, welding, or the like.

[0067] A first frame 19 and a second frame 20 are also housed inside the sealed container 100, and the first frame 19 and the second frame 20 are fastened to the second fixed scroll 112 by bolts (not shown) or the like. Reamed holes (not shown) are formed in the first frame 19, the second frame 20, and the second fixed scroll 112. The first frame 19 is connected to the second frame 20 and the second fixed scroll 112 by reamer pins (not shown) inserted into these reamed holes.

[0068] The first fixed scroll 102 is connected to the second frame 20 by guides 21 provided at two or more locations. The first fixed scroll 102 is prevented from moving in the circumferential direction by the guides 21, but is free to move in the axial direction.

[0069] The rotation prevention mechanism 5 is sandwiched in the axial direction between the first orbiting scroll 101 and the second orbiting scroll 111. The rotation prevention mechanism 5 connects the first orbiting scroll 101 to the first frame 19, and the second orbiting scroll 111 to the first frame 19, and prevents the first orbiting scroll 101 and the second orbiting scroll 111 from rotating during their orbital motion.

[0070] The first compression mechanism 30a, which includes the first orbiting scroll 101 and the first fixed scroll 102, has a function of compressing the refrigerant drawn through the suction pipe 50 and discharging the compressed refrigerant into the second space 402. The second compression mechanism 30b, which includes the second orbiting scroll 111 and the second fixed scroll 112, has a function of compressing the refrigerant drawn through the suction pipe 50 and discharging the compressed refrigerant into the first space 401.

[0071] The first orbiting scroll 101 is disposed below the first fixed scroll 102 and is supported so as to be freely swingable on the eccentric shaft portion 3 b of the rotating shaft 3. The second orbiting scroll 111 is disposed above the second fixed scroll 112 and is supported so as to be freely swingable on the eccentric shaft portion 3 b of the rotating shaft 3.

[0072] The first orbiting scroll 101 and the first fixed scroll 102 are disposed in the sealed container 100 with the first orbiting scroll 101b and the first fixed scroll 102b meshing with each other. A compression chamber 71 is formed between the first orbiting scroll 101b and the first fixed scroll 102b, and the volume of the compression chamber 71 decreases radially from the outer side to the inner side as the rotary shaft 3 rotates. That is, in the compression mechanism 30 of the scroll compressor 150, the first fixed scroll 102b and the first orbiting scroll 101b mesh with each other to form the compression chamber 71 that compresses the refrigerant.

[0073] The second orbiting scroll 111 and the second fixed scroll 112 are disposed in the sealed container 100 with the second orbiting scroll 111b and the second fixed scroll 112b meshing with each other. A compression chamber 72 is formed between the second orbiting scroll 111b and the second fixed scroll 112b, and the volume of the compression chamber 72 decreases from the outer side to the inner side in the radial direction as the rotating shaft 3 rotates. That is, in the compression mechanism 30 of the scroll compressor 150, the second fixed scroll 112b and the second orbiting scroll 111b mesh with each other to form the compression chamber 72 that compresses the refrigerant.

[0074] In the scroll compressor 150, the base circle center of the first orbiting scroll 101b is offset in the direction in which the first orbiting scroll 101b starts to wind with respect to the center of the eccentric shaft portion 3b. In the scroll compressor 150, the base circle center of the first fixed scroll 102b is offset in the direction in which the first fixed scroll 102b starts to wind with respect to the center of the main shaft portion 3a.

[0075] In the scroll compressor 150, the base circle center of the second orbiting scroll 111 is offset in the winding start direction of the second orbiting scroll 111b from the center of the eccentric shaft portion 3b. In the scroll compressor 150, the base circle center of the second fixed scroll 112b is offset in the winding start direction of the second fixed scroll 112b from the center of the main shaft portion 3a.

[0076] In the scroll compressor 150, the flattening ratio from point 1e (φrad) closest to the end of the first oscillating scroll 101b to point 1f (φ-πrad), where the base circle radius is minimal, is set smaller than the flattening ratio from point 1f (φ-πrad) to point 1g (φ-2πrad) (see FIG. 3).In the scroll compressor 150, the flattening ratio from point 2e (φrad) closest to the end of the first fixed scroll 102b to point 2f (φ-πrad), where the base circle radius is minimal, is set smaller than the flattening ratio from point 2f (φ-πrad) to point 2g (φ-2πrad) (see FIG. 3).

[0077] In the scroll compressor 150, the flattening ratio from point 1e (φrad) closest to the end of the second oscillating scroll 111b to point 1f (φ-πrad), where the base radius is minimal, is set smaller than the flattening ratio from point 1f (φ-πrad) to point 1g (φ-2πrad) (see FIG. 3).In the scroll compressor 150, the flattening ratio from point 2e (φrad) closest to the end of the second fixed scroll 112b to point 2f (φ-πrad), where the base radius is minimal, is set smaller than the flattening ratio from point 2f (φ-πrad) to point 2g (φ-2πrad) (see FIG. 3).

[0078] Of the points where the base circle radius is minimal in the first oscillating spiral body 101b, the maximum value of the tooth thickness from point 1e (φrad) closest to the end of the spiral to point 1f (φ-πrad) is set smaller than the maximum value of the tooth thickness from point 1f (φ-πrad) to point 1g (φ-2πrad).Of the points where the base circle radius is minimal in the first fixed spiral body 102b, the maximum value of the tooth thickness from point 2e (φrad) closest to the end of the spiral to point 2f (φ-πrad) is set smaller than the maximum value of the tooth thickness from point 2f (φ-πrad) to point 2g (φ-2πrad).

[0079] Of the points where the base circle radius is minimum in the second oscillating spiral body 111b, the maximum value of the tooth thickness from point 1e (φrad) closest to the end of the spiral to point 1f (φ-πrad) is set smaller than the maximum value of the tooth thickness from point 1f (φ-πrad) to point 1g (φ-2πrad).Of the points where the base circle radius is minimum in the second fixed spiral body 112b, the maximum value of the tooth thickness from point 2e (φrad) closest to the end of the spiral to point 2f (φ-πrad) is set smaller than the maximum value of the tooth thickness from point 2f (φ-πrad) to point 2g (φ-2πrad).

[0080] The portion of point 1e (φ-rad) has a larger expansion angle than the end of the first oscillating spiral 101b and may be a hypothetical point extending from the first oscillating spiral 101b. The portion of point 1e (φ-rad) has a larger expansion angle than the end of the second oscillating spiral 111b and may be a hypothetical point extending from the second oscillating spiral 111b.

[0081] Point 2e (φ-rad) has a larger expansion angle than the end of first fixed spiral body 102b and may be an imaginary point extending from first fixed spiral body 102b. Point 2e (φ-rad) has a larger expansion angle than the end of second fixed spiral body 112b and may be an imaginary point extending from second fixed spiral body 112b.

[0082] The spiral operation and shape of the first compression mechanism 30a including the first orbiting scroll 101 and the first fixed scroll 102, and the second compression mechanism 30b including the second orbiting scroll 111 and the second fixed scroll 112 are the same as those in embodiment 1. Note that the first orbiting scroll 101 and the second orbiting scroll 111 are eccentric in the same direction, but the first orbiting scroll 101 and the second orbiting scroll 111 may be eccentric in different directions. Furthermore, the shapes of the two compression mechanisms 30 do not have to be the same.

[0083] In this way, the scroll compressor 150 according to the second embodiment is configured to have two compression mechanism sections 30 inside the sealed container 100, thereby making it possible to increase the suction volume and further improve the compressor performance compared to the first embodiment.

[0084] A discharge flow path 300 is formed in the first fixed base plate 102a of the first fixed scroll 102 and the second frame 20 to discharge the refrigerant compressed in the compression chamber 71 into the second space 402. The discharge flow path 300 is a through hole formed in the first fixed base plate 102a and the second frame 20.

[0085] A discharge flow path 301 for discharging the refrigerant compressed in the compression chamber 72 to the first space 401 is formed in the second fixed base plate 112a of the second fixed scroll 112. The discharge flow path 301 is a through-hole formed in the second fixed base plate 112a. The scroll compressor 150 suppresses backflow of the compressed refrigerant by a discharge valve 13a installed at the outlet of the discharge flow path 301. The scroll compressor 150 also suppresses backflow of the compressed refrigerant by a discharge valve 13b installed at the outlet of the discharge flow path 301.

[0086] The second frame 20 fixes the relative positions of the first frame 19 and the second fixed scroll 112. A refrigerant flow path 302 that connects the first space 401 and the second space 402 is formed in the second frame 20, the first frame 19, and the second fixed scroll 112. The refrigerant flow path 302 is a through-hole formed in the second frame 20, the first frame 19, and the second fixed scroll 112.

[0087] Fig. 7 is a diagram showing the shape of the back surface of the first fixed scroll 102 of the scroll compressor 150 according to the second embodiment. Fig. 7 shows a cross section of the scroll compressor 150 according to the second embodiment shown in Fig. 6, taken along line A-A in Fig. 6. The scroll compressor 150 according to the second embodiment has two compression mechanism units 30, and therefore differs from the first embodiment in that the back pressure chamber and the discharge flow path must be formed on the same plane.

[0088] A back pressure chamber 74 is provided between the second fixed scroll 112 and the second frame 20 to press the first orbiting scroll 101 and the second orbiting scroll 111 together against the second fixed scroll 112 and seal the compression chambers 71 and 72. Refrigerant leakage from the back pressure chamber 74 to the suction space is suppressed by an annular sealing material 106. Refrigerant leakage from the second space 402, which is a high-pressure space, to the back pressure chamber 74 is suppressed by an annular sealing material 107.

[0089] The compression mechanism 30 has a plurality of discharge flow paths 300 formed inside the back pressure chamber 74, which discharge the refrigerant compressed by the compression mechanism 30. The openings of the discharge flow paths 300 on the compression chamber 71 side are located at the beginning of the spiral, and are formed on the back surface of the first fixed base plate 102a of the first fixed scroll 102 toward the center 2d of the base circle radius. Each discharge flow path 300 has an annular seal 303 installed on its outer periphery to prevent leakage into the back pressure chamber 74. The back pressure chamber 74 is preferably circular in shape to accommodate the seal 303. Furthermore, the back pressure chamber 74 cannot straddle the discharge flow paths 300.

[0090] In order to press the first orbiting scroll 101 and the second orbiting scroll 111 against the second fixed scroll 112, the area of ​​the back pressure chamber 74 needs to be sufficiently large. When the discharge flow path 300 and the back pressure chamber 74 are formed on the same plane in the scroll compressor 150, which is a through-shaft scroll compressor as in the second embodiment, the scroll compressor 150 may be configured as follows. In the scroll compressor 150, the center of the back pressure chamber 74 is offset from the center 2c of the first fixed scroll 102 toward the center 2d of the base circle to ensure a sufficient area for the back pressure chamber 74. When viewed in the axial direction of the rotating shaft 3, the center of the back pressure chamber 73 of the scroll compressor 150 is offset in the same direction as the centers of the base circles of the first fixed scroll 102b and the first orbiting scroll 101b.

[0091] The scroll compressor 150 according to the second embodiment has a configuration similar to that of the scroll compressor 150 according to the first embodiment, and therefore can achieve the same effects as those of the scroll compressor 150 according to the first embodiment.

[0092] Furthermore, the compression mechanism 30 includes two orbiting scrolls and two fixed scrolls, with the two orbiting scrolls arranged back-to-back. This configuration of the scroll compressor 150 allows for maximum utilization of space that would previously have been wasted in a compressor not having the above configuration. Therefore, compared to a compressor not having the above configuration, the scroll compressor 150 can increase the suction volume of the compression mechanism 30, which includes the orbiting scroll 1b and the fixed scroll 2b, thereby improving the compressor's capacity and energy efficiency.

[0093] Furthermore, when viewed in the axial direction of the rotary shaft 3, the center of the back pressure chamber 74 of the compression mechanism 30 is offset in the same direction as the centers of the base circles of the first fixed scroll 102b and the first oscillating scroll 101b. With this configuration, the scroll compressor 150 can apply to the back pressure chamber 74 a back pressure that overcomes the gas load of the compression mechanism 30 and seal the compression chambers 71 and 72. Therefore, the scroll compressor 150 can improve reliability and energy efficiency even when it has two compression sections.

[0094] Among scroll compressors, twin- and two-stage scroll compressors are known, in which a volute is formed on both sides of the oscillating base plate of the oscillating scroll for the purpose of increasing capacity and improving performance. These twin- and two-stage scroll compressors include a technique for dividing the oscillating base plate axially and storing an Oldham ring between the base plates to effectively utilize the space within the shell for suction volume. In this type of compressor configuration, the compressor cannot ensure sufficient area for the back pressure chamber, resulting in insufficient pressure between the tips of the volute teeth of the fixed and oscillating scrolls, which can increase loss due to internal leakage in the compression chamber.

[0095] The scroll compressor 150 has the above-described configuration, which ensures a sufficient area for the back pressure chamber 74, thereby improving reliability and energy efficiency compared to a scroll compressor not having the above-described configuration. That is, the scroll compressor 150 has the back pressure chamber 74 eccentrically aligned with the discharge flow path 300, which ensures a sufficient area for the back pressure chamber 74, thereby improving reliability and energy efficiency compared to a scroll compressor not having the above-described configuration.

[0096] Furthermore, the compression mechanism 30 has a discharge passage formed inside the back pressure chamber, through which the refrigerant compressed by the compression mechanism 30 is discharged. This configuration of the scroll compressor 150 maximizes the use of space for compression compared to compressors without the above configuration. Therefore, compared to compressors without the above configuration, the scroll compressor 150 can increase the suction volume of the compression mechanism 30, which includes the oscillating scroll 1b and the fixed scroll 2b, thereby improving the compressor's performance and energy efficiency. In other words, by arranging the back pressure chamber 74 so that it includes the discharge passage 300, the scroll compressor 150 can ensure sufficient area for the back pressure chamber 74, thereby improving reliability and energy efficiency compared to scroll compressors without the above configuration. The back pressure chamber 74 is separated from the discharge passage 300 by a seal 303.

[0097] 1 Swing scroll, 1a Swing base plate, 1b Swing spiral body, 1c Center, 1d Center, 1e Point, 1f Point, 1g Point, 1h Point, 1i Point, 2 Fixed scroll, 2a Fixed base plate, 2b Fixed spiral body, 2c Center, 2d Center, 2e Point, 2f Point, 2g Point, 2h Point, 2i Point, 2m Fixed boss portion, 3 Rotating shaft, 3a Main shaft portion, 3b Eccentric shaft portion, 3c Sub-shaft portion, 4 Frame, 5 Rotation prevention mechanism, 6 Electric mechanism portion, 6a Motor stator, 6b Motor rotor, 7 Bearing, 8 Bearing, 9 Bearing, 10 Stirrer, 11 First balance weight, 12 Second balance weight, 13 Discharge valve, 13a Discharge valve, 13b Discharge valve, 14 Sealing material, 19 First frame, 20 Second frame, 21 Guide, 30 Compression mechanism, 30a First compression mechanism, 30b Second compression mechanism, 50 Suction pipe, 51 Discharge pipe, 71 Compression chamber, 72 Compression chamber, 73 Back pressure chamber, 74 Back pressure chamber, 99 Oil reservoir, 100 Sealed container, 101 First orbiting scroll, 101a First orbiting base plate, 101b First orbiting scroll body, 102 First fixed scroll, 102a First fixed base plate, 102b First fixed scroll body, 102m First fixed boss portion, 106 Sealing material, 107 Sealing material, 111 Second orbiting scroll, 111a Second orbiting base plate, 111b Second orbiting scroll body, 112 Second fixed scroll, 112a Second fixed base plate, 112b Second fixed scroll body, 112m Second fixed boss portion, 150 scroll compressor, 200 oil supply path, 300 discharge flow path, 301 discharge flow path, 302 refrigerant flow path, 303 seal material, 401 first space, 402 second space, 403 third space.

Claims

1. A compressor having at least one oscillating scroll with an oscillating scroll formed on an oscillating base plate and at least one fixed scroll with a fixed scroll formed on a fixed base plate provided at a position opposite the oscillating scroll, and a rotating shaft penetrating the compression mechanism and having a main shaft portion and an eccentric shaft portion eccentric with respect to the main shaft portion and fixed to the oscillating scroll, wherein in the compression mechanism, a compression chamber is formed in which a refrigerant is compressed by the engagement of the fixed scroll with the oscillating scroll, the base circle center of the oscillating scroll of the oscillating scroll is offset in the direction in which the oscillating scroll starts to wind with respect to the center of the eccentric shaft portion, and the base circle center of the fixed scroll of the fixed scroll is offset in the direction in which the fixed scroll starts to wind with respect to the center of the main shaft portion, and The scroll compressor has an aspect ratio from a point (φrad) closest to the end of the winding to a point (φ-πrad) among the points at which the base circle radii of the oscillating scroll and the fixed scroll are minimal, which is set smaller than the aspect ratio from a point (φ-πrad) to a point (φ-2πrad).

2. A compression mechanism having at least one oscillating scroll with an oscillating scroll formed on an oscillating base plate, and at least one fixed scroll with a fixed scroll formed on a fixed base plate provided at a position opposite the oscillating scroll, and a rotating shaft penetrating the compression mechanism and having a main shaft portion and an eccentric shaft portion that is eccentric with respect to the main shaft portion and fixed to the oscillating scroll, wherein in the compression mechanism, a compression chamber is formed in which a refrigerant is compressed by meshing between the fixed scroll and the oscillating scroll, the base circle center of the oscillating scroll of the oscillating scroll is offset in the direction in which the oscillating scroll starts to wind with respect to the center of the eccentric shaft portion, and the base circle center of the fixed scroll of the fixed scroll is offset in the direction in which the fixed scroll starts to wind with respect to the center of the main shaft portion, and A scroll compressor in which the maximum value of the tooth thickness from a point (φrad) closest to the end of the winding to a point (φ-πrad) among the points at which the base circle radii of the oscillating scroll and the fixed scroll are respectively minimum is set to be smaller than the maximum value of the tooth thickness from a point (φ-πrad) to a point (φ-2πrad).

3. A scroll compressor as claimed in claim 1 or 2, wherein the point (φrad) has a larger extension angle than the winding end portions of the oscillating scroll and the fixed scroll, and is a virtual point formed by extending the curves of the oscillating scroll and the fixed scroll.

4. A scroll compressor as claimed in any one of claims 1 to 3, wherein the compression mechanism comprises two of the oscillating scrolls and two of the fixed scrolls, the two oscillating scrolls being arranged back-to-back.

5. A scroll compressor as described in claim 4, wherein the compression mechanism comprises a back pressure chamber formed on the back surface of one of the two fixed scrolls, which chamber communicates with the compression chamber, and when viewed in the axial direction of the rotation shaft, the center of the back pressure chamber is offset in the same direction as the base circle centers of the fixed scroll and the oscillating scroll.

6. A scroll compressor according to claim 5, wherein the compression mechanism has a discharge flow passage formed inside the back pressure chamber for discharging the refrigerant compressed by the compression mechanism.

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