Scroll Compressor

Abstract

According to the present invention, a scroll compressor comprises a shell (1) that accommodates an orbiting scroll (5), a frame (3), a fixed scroll (4), and a rotary shaft (10). The shell (1) has a first inner wall surface (2a) and a first protruding part (2b) that protrudes from the first inner wall surface (2a) to position the fixed scroll (4). The fixed scroll (4): has a fixed base plate (4a) and a fixed spiral body (4b) that is formed to protrude from the fixed base plate (4a); and, as positioned by the first protruding part (2b), is fixed to the first inner wall surface (2a) at shrink-fit parts (4c, 4d) of an outer circumferential part of the fixed base plate (4a). The shrink-fit parts (4c, 4d) include a first shrink-fit part (4c) and a second shrink-fit part (4d) that: are separated from each other in the axial direction of the rotary shaft (10) so as to sandwich a neutral axis (30) that is orthogonal to the rotary shaft (10) and passes through the center of gravity of the fixed scroll (4); and have a fixed length in the axial direction. The fixed scroll (4) is fixed to the first inner wall surface (2a) at both the first shrink-fit part (4c) and the second shrink-fit part (4d).

Description

[Technical field]

[0001] The present disclosure relates to a fixing structure for a fixed scroll in a scroll compressor. [Background technology]

[0002] Conventionally, in a scroll compressor, an orbiting scroll is supported on a frame fixed inside a shell, and a fixed scroll is provided opposite the orbiting scroll. A rotating shaft is attached to the orbiting scroll, and by rotating the rotating shaft, the orbiting scroll moves in an orbital motion relative to the fixed scroll, and the refrigerant is compressed in a compression chamber formed by combining the orbiting scroll of the orbiting scroll and the fixed scroll of the fixed scroll (for example, Patent Document 1).

[0003] In the scroll compressor of Patent Document 1, in order to expand the refrigerant suction space, the peripheral wall of the frame fixed inside the shell is eliminated, and the fixed scroll is fixed to the inner wall of the shell by shrink fitting. In this type of scroll compressor with a so-called frame outer wall-less structure, deformation of the fixed scroll when shrink fitting the fixed scroll to the shell is an issue, and in Patent Document 1, a stress absorbing part that absorbs stress from the outside in the radial direction is provided at a position radially outward from the fixed scroll body in the fixed base plate of the fixed scroll. In Patent Document 1, the stress absorbing part absorbs the stress due to fastening acting on the fixed base plate of the fixed scroll during shrink fitting, thereby suppressing deformation of the fixed scroll during shrink fitting. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Application No. 2019-508423 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in Patent Document 1, although deformation of the fixed scroll can be suppressed, if slight deformation remains, it is not possible to control the direction of deformation, i.e., whether the deformation is convex on one side of the rotating shaft or the other side. For this reason, in Patent Document 1, the tooth tip gap, which is the gap between the tooth tips of the fixed scroll and the oscillating scroll and the tooth bottom of the opposing scroll, increases or decreases from time to time compared to the ideal tooth tip gap at the time of design, and thus there is a problem that it is not possible to improve the precision of the formation of the tooth tip gap.

[0006] The present disclosure has been made to solve the above-mentioned problems, and has an object to provide a scroll compressor that can improve the accuracy of forming tooth tip gaps. [Means for solving the problem]

[0007] The scroll compressor according to the present disclosure includes a frame that holds a oscillating scroll, a fixed scroll arranged opposite the oscillating scroll, a rotating shaft that rotates the oscillating scroll, and a shell that accommodates the oscillating scroll, the frame, the fixed scroll, and the rotating shaft. The shell has a first inner wall surface and a first protrusion that protrudes from the first inner wall surface to position the fixed scroll. The fixed scroll has a fixed base plate and a fixed scroll body formed protruding from the fixed base plate. The fixed scroll is fixed to the first inner wall surface by a shrink-fitted portion on the outer periphery of the fixed base plate while being positioned by the first protrusion. The shrink-fitted portion has a first shrink-fitted portion and a second shrink-fitted portion that are spaced apart from each other and have a constant axial length, the first shrink-fitted portion and the second shrink-fitted portion having a neutral axis that passes through the center of gravity of the fixed scroll and is perpendicular to the rotation axis, and the fixed scroll is fixed to the first inner wall surface at two points, the first shrink-fitted portion and the second shrink-fitted portion. Effect of the Invention

[0008] The scroll compressor of the present disclosure is fixed to the shell at two locations, a first shrink-fit portion and a second shrink-fit portion, which are spaced apart from each other across the axial direction of the rotating shaft and have a constant axial length. With this configuration, the scroll compressor can control the deformation direction of the fixed scroll when shrink-fitting the fixed scroll to the shell, and can improve the formation accuracy of the tooth tip gap. [Brief description of the drawings]

[0009] [Figure 1] 1 is a schematic vertical sectional view of a scroll compressor according to a first embodiment. [Diagram 2] 1 is an exploded perspective view of a portion of a scroll compressor according to a first embodiment. [Diagram 3] 1 is a schematic partial vertical cross-sectional view of a main shell, a fixed scroll, and a main frame of a scroll compressor according to a first embodiment. [Figure 4] 2 is a view showing a state in which a fixed scroll is fixed to a main shell of the scroll compressor according to the first embodiment. FIG. [Diagram 5] 4 is an explanatory diagram of a tightening load acting on a first shrink-fit portion and a second shrink-fit portion when shrink-fitting a fixed scroll of the scroll compressor according to the first embodiment. FIG. [Figure 6] 5 is an explanatory diagram of a bending moment acting on a fixed scroll of the scroll compressor according to the first embodiment when the fixed scroll is shrink-fitted. FIG. [Figure 7] 4 is an explanatory view of the size relationship between the inner diameter of a main shell of the scroll compressor according to the first embodiment and the outer diameter of a shrink-fitted portion of a fixed scroll. FIG. [Figure 8] 10 is a schematic partial vertical cross-sectional view of a main shell, a fixed scroll, and a main frame of a scroll compressor according to a second embodiment. FIG. [Figure 9] 10 is a schematic enlarged cross-sectional view of a portion where a fixed scroll of a modified example of a scroll compressor according to Embodiment 2 is shrink-fitted into a main shell. FIG. [Figure 10]10 is an explanatory view of the relationship in size between the inner diameter of a main shell and the outer diameter of a shrink-fitted portion of a fixed scroll of a scroll compressor according to a second embodiment. FIG. [Figure 11] 11 is a schematic enlarged cross-sectional view of a portion where a fixed scroll of a scroll compressor according to a third embodiment is shrink-fitted into a main shell. FIG. [Figure 12] FIG. 11 is a plan view of a fixed scroll of a scroll compressor according to a third embodiment. [Figure 13] FIG. 11 is a plan view of a first modified example of a fixed scroll of the scroll compressor according to the third embodiment. [Figure 14] FIG. 11 is a plan view of a second modified example of the fixed scroll of the scroll compressor according to the third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. In each drawing, the same or corresponding parts are denoted by the same reference numerals, and the description thereof will be omitted or simplified as appropriate. In addition, the shape, size, arrangement, etc. of the configurations shown in each drawing may be changed as appropriate within the scope of the present disclosure.

[0011] Embodiment 1 A first embodiment will be described below. Fig. 1 is a schematic vertical cross-sectional view of a scroll compressor according to the first embodiment. Fig. 2 is an exploded perspective view of a part of the scroll compressor according to the first embodiment. The scroll compressor in Figs. 1 and 2 is a so-called vertical scroll compressor that is used with the central axis of the rotating shaft approximately perpendicular to the ground. In the following description, the direction in which the rotating shaft extends is called the axial direction, the direction perpendicular to the axial direction is called the radial direction, and the direction around the rotating shaft is called the circumferential direction.

[0012] The scroll compressor includes a shell 1, a main frame 3, a compression mechanism 6, a drive mechanism 14, a subframe 15, a rotating shaft 10, a bush 9, and a power supply unit 17. The scroll compressor is a so-called low-pressure shell type scroll compressor in which the inside of the shell 1 is filled with refrigerant before being compressed by the compression mechanism 6. In the following description, the main frame 3 is used as a reference, and the side where the compression mechanism 6 is provided (upper side) is designated as one end side U, and the side where the drive mechanism 14 is provided (lower side) is designated as the other end side L.

[0013] The shell 1 is a cylindrical housing made of a conductive material such as metal and has closed ends, and includes a main shell 2, an upper shell 16, and a lower shell 12. The main shell 2 is cylindrical, and a suction pipe 18 is connected to its side wall by welding or the like. The suction pipe 18 is a pipe that introduces the refrigerant into the shell 1 and communicates with the internal space of the main shell 2. The upper shell 16 is a first shell that is approximately hemispherical, and a part of its side wall is connected to the upper end of the main shell 2 by welding or the like, covering the upper opening of the main shell 2. A discharge pipe 19 is connected to the top of the upper shell 16 by welding or the like. The discharge pipe 19 is a pipe that discharges the refrigerant to the outside of the shell 1 and communicates with the internal space of the main shell 2. The lower shell 12 is a second shell that is approximately hemispherical, and a part of its side wall is connected to the lower end of the main shell 2 by welding or the like, covering the lower opening of the main shell 2.

[0014] The main frame 3 is a hollow metal frame with a cavity formed therein, and is provided inside the shell 1. The main frame 3 includes a body 3a, a main bearing 3b, and an oil return pipe 3c. The body 3a is fixed to the inner wall surface of one end side U of the main shell 2, and an accommodation space 3d is formed in the center along the longitudinal direction of the shell 1. The accommodation space 3d is open at the one end side U, and is stepped so that the space narrows toward the other end side L. An annular flat surface 3e is formed at the one end side U of the body 3a so as to surround the accommodation space 3d. A ring-shaped thrust plate 13 made of a steel plate material such as valve steel is disposed on the flat surface 3e.

[0015] Therefore, in the first embodiment, the thrust plate 13 functions as a thrust bearing. Also, an intake port 3f is formed at a position on the outer end side of the flat surface 3e of the main frame 3 that does not overlap with the thrust plate 13. The intake port 3f is a space that penetrates the main body 3a in the vertical direction, i.e., between the upper shell 16 side and the lower shell 12 side. The number of intake ports 3f is not limited to one, and multiple intake ports 3f may be formed.

[0016] An Oldham accommodation portion 3g is formed in a step portion on the other end side L of the main frame 3 from the flat surface 3e. A first Oldham groove 3h is formed in the Oldham accommodation portion 3g. The first Oldham groove 3h is formed so that a part of the outer end side is cut into the inner end side of the flat surface 3e. Therefore, when the main frame 3 is viewed from the one end side U, a part of the first Oldham groove 3h overlaps with the thrust plate 13. A pair of first Oldham grooves 3h are formed in the Oldham accommodation portion 3g. The pair of first Oldham grooves 3h are formed to face each other. The main bearing portion 3b is formed continuously with the other end side L of the body portion 3a, and a shaft hole 3i is formed therein. The shaft hole 3i penetrates the main bearing portion 3b in the vertical direction, and one end side U of the shaft hole 3i communicates with the accommodation space 3d. The oil return pipe 3c is a pipe for returning the lubricating oil accumulated in the storage space 3d to an oil reservoir inside the lower shell 12, and is inserted and fixed into an oil drain hole formed in the main frame 3, penetrating it from the inside to the outside.

[0017] The lubricating oil is, for example, a refrigeration oil containing an ester-based synthetic oil. The lubricating oil is stored in the lower part of the shell 1, i.e., the lower shell 12, and is pumped up by an oil pump 7 described later. The pumped up lubricating oil passes through an oil passage 20 in the rotating shaft 10, and reduces wear between mechanically contacting parts such as the compression mechanism 6, and improves temperature control and sealing properties of sliding parts. As the lubricating oil, an oil having excellent lubricating properties, electrical insulation properties, stability, refrigerant solubility, low-temperature fluidity, etc., and having a moderate viscosity is preferable.

[0018] The compression mechanism 6 is a compression mechanism that compresses the refrigerant. The compression mechanism 6 is a scroll compression mechanism that includes a fixed scroll 4 and a swing scroll 5. The fixed scroll 4 is made of metal such as cast iron, and includes a fixed base plate 4a and a fixed scroll 4b that is an involute-shaped protrusion formed protruding from the fixed base plate 4a. The fixed base plate 4a is disk-shaped, and a discharge port 4g is formed in the center thereof by penetrating in the vertical direction. The discharge port 4g penetrates the fixed base plate 4a from the fixed scroll 4b side to the back side on the opposite side. The fixed scroll 4b protrudes from the surface of the other end side L of the fixed base plate 4a to form a spiral-shaped wall, and its tip protrudes to the other end side L. The fixed scroll 4 is fixed to the main shell 2 by shrink fitting. The fixed scroll 4 is disposed opposite the swing scroll 5. The scroll compressor has a so-called frameless structure in which a fixed scroll 4 is fixed to the inner wall surface of a shell 1 .

[0019] As shown in FIG. 2, a groove 4aa is formed on the outer peripheral surface of the fixed base plate 4a over the entire circumference. The groove 4aa is formed on the outer peripheral surface of the fixed base plate 4a so as to extend in the circumferential direction. The groove 4aa is configured so that the axial position and the axial opening length hc (see FIG. 4 described later) are constant over the circumferential direction. The groove 4aa forms an annular inner space 4ab (see FIG. 1) between the outer peripheral surface of the fixed base plate 4a and the inner peripheral surface of the main shell 2, and the outer periphery of the fixed scroll 4 is divided in the axial direction. Note that, although the groove 4aa is formed on the outer peripheral surface of the fixed base plate 4a over the entire circumference in FIG. 2, it may be formed intermittently in the circumferential direction on the outer peripheral surface.

[0020] Of the outer periphery of the fixed base plate 4a, a portion located on one end side U from the groove 4aa and a portion located on the other end side L from the groove 4aa constitute a shrink-fitted portion fixed to the main shell 2. The shrink-fitted portion is an outer periphery of the fixed base plate 4a and extends in the circumferential direction. Hereinafter, the shrink-fitted portion located on the one end side U in the axial direction is referred to as the first shrink-fitted portion 4c, and the shrink-fitted portion located on the other end side L in the axial direction is referred to as the second shrink-fitted portion 4d. The first shrink-fitted portion 4c and the second shrink-fitted portion 4d are formed on both sides in the axial direction of the middle space 4ab. The axial length h1 (see FIG. 4 described later) of the first shrink-fitted portion 4c is constant in the circumferential direction, and the axial length h2 (see FIG. 4 described later) of the second shrink-fitted portion 4d is constant in the circumferential direction. The fixed scroll 4 is fixed to the main shell 2 by shrink fitting at two points in the axial direction, that is, at a first shrink fitting portion 4c and a second shrink fitting portion 4d.

[0021] The fixed base plate 4a of the fixed scroll 4 has a first portion 40 having a plate-like first shrink-fit portion 4c perpendicular to the axial direction, a flat second portion 41 having a plate-like second shrink-fit portion 4d perpendicular to the axial direction, and a plate-like intermediate portion 42 between the first portion 40 and the second portion 41. The fixed base plate 4a has a configuration in which the first portion 40, the intermediate portion 42, and the second portion 41 are integrated together and aligned in this order in the axial direction.

[0022] The swing scroll 5 is made of a metal such as aluminum, and includes a swing base plate 5a, a swing scroll 5b which is an involute-shaped protrusion formed protruding from the swing base plate 5a, and a cylindrical portion 5c. The swing scroll 5 is disposed in the refrigerant intake space 21 between the fixed scroll 4 and the main frame 3. The swing base plate 5a has a disk shape including one surface on which the fixed scroll 4b is formed, the other surface opposite to the one surface, and a side surface 5f which is a surface connecting the one surface and the other surface and is located at the outermost position in the radial direction. At least a part of the outer peripheral region of the other surface is a sliding surface 5e which slides against the thrust plate 13.

[0023] The oscillating base plate 5a is supported by the main frame 3 so that the sliding surface 5e can slide on the thrust plate 13. The oscillating scroll 5b protrudes from one surface of the oscillating base plate 5a to form a spiral wall, and its tip protrudes to one end side U. Note that a sealing member (not shown) is provided at the tip of the fixed scroll 4 and the tip of the oscillating scroll 5b of the oscillating scroll 5 to prevent leakage of the refrigerant.

[0024] The cylindrical portion 5c is a cylindrical boss formed to protrude from approximately the center of the other surface of the oscillating plate 5a toward the other end side L. A rocking bearing, a so-called journal bearing, which rotatably supports a slider 9a described later, is provided on the inner peripheral surface of the cylindrical portion 5c so that its central axis is parallel to the central axis of the rotating shaft 10. A second Oldham groove 5d is formed on the other surface of the oscillating plate 5a. The second Oldham groove 5d is an oval groove. A pair of the second Oldham grooves 5d are formed on the other surface of the oscillating plate 5a. The line connecting the pair of second Oldham grooves 5d is provided so as to be perpendicular to the line connecting the pair of first Oldham grooves 3h.

[0025] An Oldham ring 8 is provided in the Oldham accommodation portion 3g of the main frame 3. The Oldham ring 8 includes a ring portion 8a, a first key portion 8b, and a second key portion 8c. A pair of the first key portions 8b is formed on the surface of the other end side L of the ring portion 8a. The pair of first key portions 8b are formed to face each other and are accommodated in a pair of first Oldham grooves 3h of the main frame 3. A pair of second key portions 8c is formed on the surface of one end side U of the ring portion 8a. The pair of second key portions 8c are formed to face each other and are accommodated in a pair of second Oldham grooves 5d of the orbiting scroll 5. When the orbiting scroll 5 revolves by the rotation of the rotating shaft 10, the first key portion 8b slides in the first Oldham groove 3h, and the second key portion 8c slides in the second Oldham groove 5d. As a result, the Oldham ring 8 prevents the orbiting scroll 5 from rotating on its axis.

[0026] The fixed scroll 4b of the fixed scroll 4 and the swing scroll 5b of the swing scroll 5 are meshed with each other to form a compression chamber 4h. The compression chamber 4h has a volume that decreases from the outside to the inside in the radial direction, so the refrigerant is taken in from the outer end side of the scroll and gradually compressed by moving it toward the center. The compression chamber 4h communicates with the discharge port 4g at the center of the fixed scroll 4. A discharge valve 11 is provided on the surface of one end side U of the fixed scroll 4 to open and close the discharge port 4g in a predetermined manner to prevent the refrigerant from flowing back. The refrigerant compressed in the compression chamber 4h is discharged into the discharge space 16a in the upper shell 16 through the discharge port 4g and the discharge valve 11. The discharge space 16a is a high-pressure space due to the refrigerant discharged from the discharge port 4g.

[0027] The refrigerant may be, for example, a halogenated hydrocarbon having a carbon double bond in its composition, a halogenated hydrocarbon having no carbon double bonds, a hydrocarbon, or a mixture containing them. The halogenated hydrocarbon having a carbon double bond is an HFC refrigerant or a fluorocarbon-based low GWP refrigerant, which has an ozone depletion potential of zero. The halogenated hydrocarbon having a carbon double bond is a halogenated hydrocarbon having a chemical formula of C 3 H 2 F 4 Examples of halogenated hydrocarbons that do not have a carbon double bond include tetrafluoropropenes such as HFO1234yf, HFO1234ze, and HFO1243zf, which are represented by the formula: 2 F 2 Examples of refrigerants include refrigerants in which R32 (difluoromethane) and R41 are mixed, as represented by the formula: Hydrocarbons include natural refrigerants such as propane and propylene. Examples of mixtures include mixed refrigerants in which HFO1234yf, HFO1234ze, and HFO1243zf are mixed with R32 or R41.

[0028] The drive mechanism 14 is provided on the other end L of the main frame 3 inside the shell 1. The drive mechanism 14 includes a stator 14a and a rotor 14b. The stator 14a is a ring-shaped stator formed by winding a winding around an iron core formed of, for example, a plurality of laminated electromagnetic steel sheets via an insulating layer. The stator 14a is fixed and supported inside the main shell 2 by shrink fitting or the like. The rotor 14b is a cylindrical rotor having a permanent magnet built in an iron core formed of a plurality of laminated electromagnetic steel sheets and a through hole penetrating in the vertical direction in the center. The rotor 14b is disposed in the internal space of the stator 14a. The rotor 14b is disposed with a predetermined gap between its outer circumferential surface and the inner circumferential surface of the stator 14a.

[0029] The subframe 15 is a metal frame and is provided inside the shell 1 on the other end side L of the drive mechanism 14. The subframe 15 is fixedly supported on the inner peripheral surface of the other end side L of the main shell 2 by shrink fitting, welding, or the like. The subframe 15 is provided with an auxiliary bearing 15a and an oil pump 7. The auxiliary bearing 15a is a ball bearing provided on the upper central side of the subframe 15 and has a hole penetrating in the vertical direction at the center. The oil pump 7 is provided on the lower central side of the subframe 15 and is arranged so that at least a part of it is immersed in the lubricating oil stored in an oil reservoir of the shell 1.

[0030] The rotating shaft 10 is a long metal rod-shaped member and is provided inside the shell 1. The rotating shaft 10 includes a main shaft portion 10a and an eccentric shaft portion 10b. The main shaft portion 10a is a shaft constituting a main portion of the rotating shaft 10, and is arranged so that its central axis coincides with the central axis of the main shell 2. The rotor 14b is fixed to the outer surface of the main shaft portion 10a in contact with it. The eccentric shaft portion 10b is provided on one end side U of the main shaft portion 10a so that its central axis is eccentric with respect to the central axis of the main shaft portion 10a. The rotating shaft 10 has one end side U of the main shaft portion 10a inserted into the main bearing portion 3b of the main frame 3, and the other end side L inserted and fixed into the sub-bearing portion 15a of the sub-frame 15. As a result, the eccentric shaft portion 10b is arranged inside the cylindrical portion 5c of the fixed scroll 4.

[0031] A first balancer 10c is provided on one end U of the main shaft portion 10a of the rotating shaft 10, and a second balancer 10d is provided on the other end U of the main shaft portion 10a. The first balancer 10c and the second balancer 10d are provided to offset imbalance caused by the swing of the swing scroll 5. In addition, the rotating shaft 10 is provided with an oil passage 20 that penetrates the inside of the main shaft portion 10a and the eccentric shaft portion 10b in the axial direction.

[0032] The bush 9 is made of a metal such as iron, and is a connecting member that connects the orbiting scroll 5 and the rotating shaft 10. As shown in FIG. 2, the bush 9 is composed of two parts: a slider 9a and a balance weight 9b. The slider 9a is a cylindrical member with a flange formed on the other end side L, and is fitted into an annular gap between the eccentric shaft part 10b and the cylindrical part 5c of the fixed scroll 4. The balance weight 9b is a donut-shaped member with a weight part 9c that has a substantially C-shaped shape when viewed from the one end side U, and is provided eccentrically with respect to the center of rotation to offset the centrifugal force of the orbiting scroll 5. The balance weight 9b is fixed to the flange of the slider 9a by a method such as shrink fitting.

[0033] The power supply unit 17 is a power supply member that supplies power to the scroll compressor, and is fixed to the outer circumferential surface of the main shell 2 of the shell 1. The power supply unit 17 includes a cover 17a, a power supply terminal 17b, and a wire 17c. The cover 17a is a cylindrical cover member having a bottom on the side fixed to the main shell 2. The power supply terminal 17b is made of a metal member, one side of which is provided inside the cover 17a, and the other side of which is provided inside the shell 1. One side of the wire 17c is connected to the power supply terminal 17b, and the other side is connected to the stator 14a.

[0034] Next, the relationship between the main shell 2 and the compression mechanism 6 will be described with reference to FIGS.

[0035] FIG. 3 is a schematic vertical partial cross-sectional view of the main shell, the fixed scroll, and the main frame of the scroll compressor according to the first embodiment. FIG. 4 is a view showing a state in which the fixed scroll is fixed to the main shell of the scroll compressor according to the first embodiment. As shown in FIG. 3, the main shell 2 has a first inner wall surface 2a, a first protruding portion 2b protruding from the first inner wall surface 2a and positioning the fixed scroll 4, and a first positioning surface 2c facing the one end side U in the first protruding portion 2b. The main shell 2 further has a second inner wall surface 2d of the first protruding portion 2b, a second protruding portion 2e protruding from the second inner wall surface 2d and positioning the main frame 3, and a second positioning surface 2f facing the one end side U in the second protruding portion 2e. The fixed scroll 4 is shrink-fitted and fixed to the first inner wall surface 2a in a state in which it is positioned by the first positioning surface 2c. Moreover, the main shell 2 is fixed to the second inner wall surface 2d by shrink fitting in a state where it is positioned by the second positioning surface 2f.

[0036] The first positioning surface 2c has a recess 2g, which is a so-called recess. The role of the recess 2g is as follows. During cutting to form the first protruding portion 2b on the main shell 2, the connection portion between the first inner wall surface 2a and the first positioning surface 2c is likely to be a curved surface rather than a right angle. If this portion is a curved surface, even if the fixed scroll 4 is placed on the first protruding portion 2b, it will not contact the first positioning surface 2c and will float, resulting in low positioning accuracy. In contrast, if the recess 2g is formed on the first positioning surface 2c, the fixed scroll 4 can be surely in contact with the first positioning surface 2c, thereby improving positioning accuracy. The recess 2h formed on the second positioning surface 2f is also a so-called recess, which has the same function as the recess 2g. If the recess 2h is formed on the second positioning surface 2f, the main shell 2 can be surely in contact with the second positioning surface 2f, thereby improving positioning accuracy.

[0037] As shown in Fig. 3 and Fig. 4, the fixed scroll 4 is fixed to the first inner wall surface 2a by shrink fitting at two axial locations, i.e., the first shrink fitting portion 4c and the second shrink fitting portion 4d. The first shrink fitting portion 4c and the second shrink fitting portion 4d are provided to sandwich the neutral axis 30 in the axial direction of the rotating shaft 10. The neutral axis 30 is an axis that passes through the center of gravity 4e of the fixed scroll 4 and is perpendicular to the rotating shaft 10. The center of gravity 4e is the center of gravity of the entire fixed scroll. The first shrink fitting portion 4c and the second shrink fitting portion 4d are configured to be spaced apart from each other with the neutral axis 30 sandwiched in the axial direction of the rotating shaft 10 by forming the groove 4aa at a position including the neutral axis 30 in the axial direction of the rotating shaft 10.

[0038] The radial length ra of the groove 4aa forming the middle space 4ab is not particularly limited as long as the necessary wall thickness rb that can withstand the high pressure acting on the discharge port 4g can be secured. The necessary wall thickness rb is the thickness between the discharge port 4g and the groove 4aa in the radial direction. With regard to the radial length ra of the groove 4aa, for example, the groove 4aa may be extended radially inward to the position shown by the dotted line in FIG. 4, and the length ra may be lengthened to a position where the middle space 4ab overlaps with the fixed scroll body 4b of the fixed scroll 4 as viewed in the axial direction. By lengthening the length ra to enlarge the middle space 4ab, the scroll compressor can reduce the weight of the fixed scroll 4 and reduce the amount of raw material.

[0039] 5 is an explanatory diagram of a tightening load acting on the first shrink-fitted portion and the second shrink-fitted portion when shrink-fitting the fixed scroll of the scroll compressor according to the first embodiment. When the fixed scroll 4 is shrink-fitted to the main shell 2, a load due to shrink-fitting acts on each of the first shrink-fitted portion 4c and the second shrink-fitted portion 4d of the fixed scroll 4, as shown by the white arrows in FIG. 5. This load is a tightening load acting radially inward from the main shell 2.

[0040] Here, the axial center line (hereinafter, the first load line) 31 of the fastening load received by the first shrink-fitted portion 4c and the axial center line (hereinafter, the second load line) 32 of the fastening load received by the second shrink-fitted portion 4d do not intersect with the neutral axis 30 of the fixed scroll 4. In other words, the scroll compressor is formed so that the direction of the fastening load received by each of the first shrink-fitted portion 4c and the second shrink-fitted portion 4d is parallel to the neutral axis 30 and perpendicular to the rotation axis 10. Specifically, the axial length h1 of the first shrink-fitted portion 4c is constant in the circumferential direction, and the axial length h2 of the second shrink-fitted portion 4d is constant in the circumferential direction. As a result, the direction of the fastening load received by each of the first shrink-fitted portion 4c and the second shrink-fitted portion 4d is parallel to the neutral axis 30 and perpendicular to the rotation axis 10.

[0041] Next, the operation of the above-mentioned configuration will be described with reference to FIG.

[0042] FIG. 6 is an explanatory diagram of the bending moment acting on the fixed scroll when the fixed scroll of the scroll compressor according to the first embodiment is shrink-fitted. As described above, the fixed scroll 4 is fixed at two axial positions on the outer circumferential surface of the fixed base plate 4a, and the first shrink-fitted portion 4c and the second shrink-fitted portion 4d, which are the fixed portions, are provided on either side of the neutral axis 30. The axial lengths h1 and h2 of the first shrink-fitted portion 4c and the second shrink-fitted portion 4d are constant. In other words, the axial lengths h1 and h2 of the first shrink-fitted portion 4c and the second shrink-fitted portion 4d are constant in the circumferential direction, that is, do not change in the circumferential direction. Note that h1 and h2 may be the same as each other or may be different.

[0043] With the above configuration, the scroll compressor controls the direction of deformation of the first portion 40 and the second portion 41 of the fixed scroll 4 during shrink fitting to intentionally cause deformation in the opposite direction, thereby improving the accuracy of the tooth tip gap, as described below. Here, the tooth tip gap refers to the gap between the tooth tip of the fixed scroll 4b and the tooth bottom of the opposing scroll, the oscillating scroll 5. The tooth tip gap also refers to the gap between the tooth tip of the oscillating scroll 5b and the tooth bottom of the opposing scroll, the fixed scroll 4.

[0044] A tightening load is applied to the first part 40 including the first shrink-fitted portion 4c on the one end side U rather than the neutral axis 30 during shrink-fitting, so that a convex bending moment acts on the other end side L as shown by dotted line 50. As a result, the first part 40 tries to deform convexly towards the other end side L. On the other hand, a tightening load is applied to the second part 41 including the second shrink-fitted portion 4d on the other end side L rather than the neutral axis 30 during shrink-fitting, so that a convex bending moment acts on the one end side U as shown by dotted line 51. As a result, the second part 41 tries to deform convexly towards the one end side U.

[0045] That is, by providing the first shrink-fitted portion 4c and the second shrink-fitted portion 4d on either side of the neutral axis 30, bending moments in opposite directions act on the first portion 40 and the second portion 41. This bending moment generates stresses in the first portion 40 and the second portion 41 that cause distortions in directions that move the first portion 40 and the second portion 41 toward each other, as shown by the open arrows in Fig. 6, and the stresses are offset, thereby suppressing deformation of the fixed scroll 4. Therefore, the scroll compressor having the above configuration can suppress deformation of the fixed scroll 4 compared to a configuration in which the fixed scroll 4 is shrink-fitted at one location using the entire outer circumferential surface of the fixed scroll 4.

[0046] Here, consider the case where the first load line 31 and the second load line 32 are not parallel to the neutral axis 30 but intersect with it. In this case, a tightening load due to shrink fitting is applied to a surface including the neutral axis 30, and depending on the position, it is unclear whether the deformation of the fixed scroll 4 will be convex toward one end side U or convex toward the other end side L.

[0047] On the other hand, in the above configuration, since the first load line 31 and the second load line 32 are parallel to the neutral axis 30, the tightening load due to shrink fitting is not applied to the surface including the neutral axis 30. Therefore, the above configuration does not cause a phenomenon in which it is unclear whether the deformation will be convex on the one end side U or convex on the other end side L. Note that, when the grooves 4aa are intermittently formed on the outer peripheral surface of the fixed base plate 4a, the portions between the adjacent grooves 4aa are fixed to the first inner wall surface 2a of the main shell 2 by shrink fitting. Therefore, in the case of this configuration, although a tightening load due to shrink fitting is applied to the surface including the neutral axis 30, the grooves 4aa may be intermittently formed in the circumferential direction on the outer peripheral surface of the fixed base plate 4a to such an extent that it does not cause a phenomenon in which the deformation direction is unclear.

[0048] In the conventional configuration with a stress absorbing portion, the stress acting on the fixed scroll can be absorbed by shrink fitting to suppress deformation, but the direction of deformation cannot be controlled, and therefore the tooth tip gap cannot be set to the ideal value as designed.

[0049] In contrast, in the scroll compressor with the above configuration, the phenomenon that it is not clear whether the fixed scroll 4 will deform to one end side U or the other end side L is eliminated, and the direction of deformation is controlled so that deformation occurs in the opposite directions. This allows the scroll compressor to configure the tooth tip gap to be the ideal tooth tip gap as designed. In addition, the above configuration can suppress deformation caused by shrink fitting the fixed scroll 4, so that the ideal spiral shape of the fixed scroll 4 can be prevented from being destroyed, and a decrease in compression efficiency can be suppressed.

[0050] Incidentally, the position of the center of gravity G is affected by the size of the scroll, the configuration of the base plate, the shape of the back side of the scroll, etc. For this reason, in the scroll compressor of the first embodiment, these parameters that affect the center of gravity G are adjusted so that the center of gravity G of the fixed scroll 4 is located within the fixed base plate 4a.

[0051] The position of the center of gravity G can be adjusted as follows. · Form a thickened portion with an increased thickness of the fixed platen 4a on the discharge side surface of the fixed platen 4a. As a result, the position of the center of gravity G rises. It is desirable that the thickness of the thickened portion is equal to or greater than the length h1 of the first shrink fitting portion 4c and the length h2 of the second shrink fitting portion 4d. · Increase the thickness of the entire fixed platen 4a. As a result, the position of the center of gravity G rises. · Ensure that the radial length ra of the groove 4aa and the required wall thickness rb satisfy ra < rb. This suppresses the lowering of the center of gravity position due to providing the hollow space 4ab in the fixed platen 4a. It is desirable that ra is a length such that the hollow space 4ab does not overlap the fixed spiral scroll 4b of the fixed scroll 4 when viewed in the axial direction.

[0052] Here, in a scroll compressor where the center of gravity is not within the thickness of the fixed platen (for example, International Publication No. 2019 / 207785), since the neutral axis does not pass through the fixed platen, a structure in which the neutral axis is sandwiched between two shrink fitting portions in the fixed platen cannot be configured. Therefore, with this known configuration, it is not possible to control the deformation direction of the fixed scroll 4 during shrink fitting of the fixed scroll 4 to the shell 1 of the fixed scroll 4, and it is not possible to improve the formation accuracy of the tip clearance.

[0053] On the other hand, the scroll compressor of Embodiment 1 is configured such that the position of the center of gravity G is located within the fixed platen 4a, and has a structure in which the neutral axis 30 passing through the center of gravity G is sandwiched between the first shrink fitting portion 4c and the second shrink fitting portion 4d. As a result, the scroll compressor of Embodiment 1 can control the deformation direction of the fixed scroll 4 during shrink fitting of the fixed scroll 4 to the shell 1 of the fixed scroll 4, and can improve the formation accuracy of the tip clearance.

[0054] Even if the center of gravity position is adjusted as described above, the center of gravity G may be shifted from the center of the thickness of the fixed base plate 4a and positioned on the volute side or the discharge side. If the center of gravity G is shifted from the center of the thickness of the fixed base plate 4a, it becomes difficult to balance the magnitude of the vector in the distortion direction shown in FIG. 6. The magnitude of the vector is determined by the moment of (the distance between the center of the load due to shrink fitting and the neutral axis) x (the magnitude of the load due to the shrink fitting allowance). For this reason, for example, if the center of gravity G is shifted downward from the center of the thickness of the fixed base plate 4a, it is desirable to adjust the vector by setting the axial length h1 of the first shrink fitting portion 4c < the axial length h2 of the second shrink fitting portion 4d.

[0055] Next, the relationship in size between the inner diameter of the main shell 2 and the outer diameter of the shrink-fitted portion of the fixed scroll 4 will be described with reference to FIG.

[0056] Fig. 7 is an explanatory diagram of the size relationship between the inner diameter of the main shell and the outer diameter of the shrink-fitted portion of the fixed scroll of the scroll compressor according to embodiment 1. Note that Fig. 7 is a diagram for explaining the positions of the dimensions r1 to r4, and does not accurately show the shapes and sizes.

[0057] As shown in Fig. 7, r1 is the inner diameter of the first inner wall surface 2a, and r2 is the inner diameter of the second inner wall surface 2d. r3 is the outer diameter of the first portion 40 of the fixed base plate 4a, and r4 is the outer diameter of the second portion 41 of the fixed base plate 4a. In the first embodiment, the relationship r3=r4>r1>r2 holds. In the scroll compressor of the first embodiment, r1 to r4 are designed in consideration of this magnitude relationship, the strength of the fixed scroll 4, the retention force of the shrink fit, and interference with other parts.

[0058] Next, the operation of the scroll compressor will be described. When electricity is applied to the power supply terminal 17b of the power supply unit 17, torque is generated in the stator 14a and the rotor 14b, and the rotating shaft 10 rotates accordingly. The rotation of the rotating shaft 10 is transmitted to the orbiting scroll 5 via the eccentric shaft portion 10b and the bush 9. The orbiting scroll 5 to which the rotational driving force is transmitted is restricted from rotating on its own axis by the Oldham ring 8, and performs an eccentric orbital motion relative to the fixed scroll 4. At that time, the other surface of the orbiting scroll 5 slides against the thrust plate 13.

[0059] The refrigerant sucked into the shell 1 from the suction pipe 18 by the swinging motion of the swing scroll 5 reaches the refrigerant intake space 21 through the suction port 3f of the main frame 3 and is taken into the compression chamber 4h formed by the fixed scroll 4 and the swing scroll 5. The refrigerant is compressed by reducing its volume as it moves from the outer periphery toward the center with the eccentric revolution of the swing scroll 5. During the eccentric revolution of the swing scroll 5, the swing scroll 5 moves radially together with the bush 9 due to its own centrifugal force, and the side wall surfaces of the fixed scroll 4b and the swing scroll 5b come into close contact with each other. The compressed refrigerant is discharged from the discharge port 4g of the fixed scroll 4 and discharged to the outside of the shell 1 against the discharge valve 11.

[0060] Next, the process of assembling the fixed scroll 4 to the main shell 2 of the scroll compressor according to the first embodiment will be described with reference to FIG.

[0061] The process from the cutting process for forming the first protrusion 2b on the inner wall surface of the main shell 2 to the process before inserting the fixed scroll 4 is the same as that of a conventional scroll compressor having a frame-less outer wall structure (for example, International Publication No. 2018 / 078787). In this specification, the insertion of the fixed scroll 4 into the main shell 2 will be described.

[0062] First, the fixed scroll 4 is inserted from one end U of the main shell 2. The rotating shaft 10, bushing 9, Oldham ring 8, and swing scroll 5 are inserted before the fixed scroll 4. The fixed scroll 4 comes into surface contact with the first positioning surface 2c of the first protruding portion 2b, and is positioned in the axial direction. Here, since a recess 2g is formed in the first positioning surface 2c of the main shell 2, the fixed scroll 4 can reliably come into contact with the first positioning surface 2c, and thus is positioned with high accuracy.

[0063] The fixed scroll 4 is shrink-fitted into the main shell 2 while being positioned on the first positioning surface 2c. That is, the main shell 2 is heated to expand, and the fixed scroll 4 is inserted into the main shell 2. By heating and expanding the main shell 2, the fixed scroll 4 having outer diameters r3 and r4 larger than the inner diameter r1 of the main shell 2 can be inserted into the main shell 2.

[0064] When the fixed scroll 4 is shrink-fitted to the main shell 2 in a state where it is positioned with high accuracy as described above, the deformation of the fixed scroll 4 is suppressed as described above. Therefore, in the scroll compressor, it is possible to suppress the collapse of the spiral shape of the fixed scroll 4, the tooth tip gap can be configured to be the ideal tooth tip gap at the time of design, and the compression efficiency can be maintained. At the same time that the fixed scroll 4 is shrink-fitted and fixed to the main shell 2, the main frame 3 is also shrink-fitted to the main shell 2. The main frame 3 is fixed to the second inner wall surface 2d by shrink fitting or the like in a state where the positioning accuracy is increased by the recess 2h in the second positioning surface 2f of the main shell 2. The method of fixing the main frame 3 to the main shell 2 is not limited to shrink fitting, and other fixing methods may be used.

[0065] Finally, the upper shell 16 is inserted from one end U of the main shell 2, and then the main shell 2 and the upper shell 16 are fixed to the main shell 2 by welding or arc spot welding.

[0066] The above-described manufacturing method allows the scroll compressor to have a frame outer wall-less structure, thereby ensuring a large refrigerant intake space 21, while controlling the deformation direction of the first portion 40 and the second portion 41 of the fixed base plate 4a, thereby suppressing deformation of the fixed scroll 4. As a result, the above-described manufacturing method allows the fixed scroll 4 to be fixed to the main shell 2 while maintaining an ideal tooth tip gap, thereby providing a scroll compressor with little performance loss.

[0067] As described above, the scroll compressor of the first embodiment includes the main frame 3 that holds the orbiting scroll 5, the fixed scroll 4 that is disposed opposite the orbiting scroll 5, a rotating shaft that rotates the orbiting scroll 5, and the shell 1 that houses them. The shell 1 has a first inner wall surface 2a and a first protruding portion 2b that protrudes from the first inner wall surface 2a to position the fixed scroll 4. The fixed scroll 4 has a fixed base plate 4a and a fixed spiral body 4b formed protruding from the fixed base plate 4a, and is fixed to the first inner wall surface 2a by a shrink-fitted portion on the outer periphery of the fixed base plate 4a in a state where it is positioned by the first protruding portion 2b. The shrink-fitted portion has a first shrink-fitted portion 4c and a second shrink-fitted portion 4d that are spaced apart from each other across a neutral axis 30 that passes through the center of gravity 4e of the fixed scroll 4 and is perpendicular to the rotation axis in the axial direction of the rotation axis 10, and have the same and constant axial lengths. The fixed scroll 4 is fixed to the first inner wall surface 2a at two locations, a first shrink-fit portion 4c and a second shrink-fit portion 4d.

[0068] With the above-described configuration, the scroll compressor can control the deformation direction of the fixed scroll 4 when the fixed scroll 4 is shrink-fitted into the shell 1, and can improve the accuracy of forming the tooth tip gaps.

[0069] In the case of fixing by shrink fitting, if the shrink fitting allowance is small, the shrink fitting holding force is also small, and when the pressure in the compression chamber 4h becomes greater than the pressure in the discharge space 16a, the fixed scroll 4 floats up, causing a breakdown in the compressor. Also, if the shrink fitting allowance is too large, the fixed scroll 4 is deformed and distorted by the stress caused by the fastening from the shell 1 during shrink fitting, and the involute shape of the fixed scroll body 4b is destroyed, which may reduce the compression efficiency.

[0070] In contrast, in the scroll compressor of embodiment 1, even if the shrink-fit allowance of the fixed scroll 4 is increased, stresses that cause displacements in opposite directions are generated in the first portion 40 and the second portion 41 and these stresses cancel each other out, thereby suppressing deformation of the fixed scroll 4. Thus, the scroll compressor of embodiment 1 can improve the shrink-fit retention force while suppressing deformation of the fixed scroll 4 and suppressing a decrease in compression efficiency.

[0071] Further, a groove 4aa extending in the circumferential direction is formed on the outer peripheral surface of the fixed scroll 4, and an intermediate space 4ab is formed between the outer peripheral surface of the fixed scroll 4 and the first inner wall surface 2a of the shell 1. In the scroll compressor, a first shrink-fit portion 4c and a second shrink-fit portion 4d are formed on both sides of the intermediate space 4ab in the axial direction.

[0072] As configured above, a groove 4aa extending in the circumferential direction is formed on the outer peripheral surface of the fixed scroll 4, so that a first shrink-fit portion 4c and a second shrink-fit portion 4d are formed axially spaced apart from each other on the outer peripheral portion of the fixed scroll 4.

[0073] Moreover, the intermediate space 4ab overlaps the fixed scroll body 4b of the fixed scroll 4 when viewed in the axial direction.

[0074] With the above configuration, the scroll compressor can reduce the weight of the fixed scroll 4 and the amount of raw materials used, compared to a configuration in which the middle space 4ab is located radially outward of the fixed scroll body 4b of the fixed scroll 4 as viewed in the axial direction.

[0075] In addition, the fixed base plate 4a of the fixed scroll 4 has a first portion 40 which is plate-shaped and has a first shrink-fit portion 4c perpendicular to the axial direction, and a second portion 41 which is plate-shaped and has a second shrink-fit portion 4d perpendicular to the axial direction, and the outer diameter of the first portion 40 is the same as the outer diameter of the second portion 41.

[0076] When the outer diameter of the first portion 40 is the same as the outer diameter of the second portion 41 as in the above configuration, the fixed scroll 4 and the first inner wall surface 2a of the shell 1 are easily manufactured.

[0077] The shell 1 further has a second inner wall surface 2d and a second protrusion 2e that protrudes from the second inner wall surface 2d and positions the main frame 3, and the main frame 3 is fixed to the second inner wall surface 2d while being positioned by the second protrusion 2e.

[0078] With the above-described configuration, the fixed scroll 4 and the main frame 3 can be fixed to the shell 1 in the same manner in a series of manufacturing steps, which makes manufacturing easier.

[0079] Embodiment 2 The second embodiment differs from the first embodiment in the shape of the fixed base plate 4a of the fixed scroll 4 and the shape of the first inner wall surface 2a of the main shell 2. Other configurations are the same as or equivalent to those of the first embodiment. The following description will focus on the configurations of the second embodiment that are different from the first embodiment, and the configurations not described in the second embodiment are the same as those of the first embodiment.

[0080] 8 is a schematic vertical partial cross-sectional view of a main shell, a fixed scroll, and a main frame of a scroll compressor according to a second embodiment. In the first embodiment, the fixed scroll 4 has the same outer diameter r3 of the first part 40 and the outer diameter r4 of the second part 41 as shown in FIG. 7, but in the second embodiment, the outer diameter r3 of the first part 40 is larger than the outer diameter r4 of the second part 41. In other words, the outer diameter r4 of the second part 41 is smaller than the outer diameter r3 of the first part 40. The scroll compressor has a configuration in which the first protruding part 2b extends to one end side U into a gap between the outer peripheral surface of the second part 41 and the first inner wall surface 2a formed by the small outer diameter r4 of the second part 41.

[0081] The tip surface of the extension portion constitutes the first positioning surface 2c, and the inner wall surface of the extension portion constitutes a part of the first inner wall surface 2a. That is, the first inner wall surface 2a is configured in a one-step staircase shape. Hereinafter, the surface of the first inner wall surface 2a on the one end side U from the first positioning surface 2c is referred to as the first partial inner wall surface 2aa, and the surface on the other end side L is referred to as the second partial inner wall surface 2ab. In addition, the dotted lines shown in FIG. 8 in the main shell 2 indicate the positions of the first inner wall surface 2a and the first positioning surface 2c before the first protrusion 2b is extended for reference.

[0082] The fixed scroll 4 is positioned by the surface of the other end side L of the first portion 40 abutting against the first positioning surface 2c. In other words, the fixed scroll 4 is positioned by the first shrink-fitted portion 4c, which is the one of the first shrink-fitted portion 4c and the second shrink-fitted portion 4d that is farther from the fixed scroll body 4b in the axial direction, abutting against the step portion of the first inner wall surface 2a. The fixed scroll 4 is fixed to the stepped first inner wall surface 2a by shrink fitting. Specifically, the first shrink-fitted portion 4c is fixed to the first partial inner wall surface 2aa, and the second shrink-fitted portion 4d is fixed to the second partial inner wall surface 2ab.

[0083] In the second embodiment as well, the fixed scroll 4 is positioned by contacting with the first positioning surface 2c of the main shell 2, and is fixed to the first inner wall surface 2a by shrink fitting. Thus, in the second embodiment as well, the same effects as those in the first embodiment can be obtained.

[0084] Another example in which the first inner wall surface 2a is formed in a step shape with one step will be described below.

[0085] 9 is a schematic enlarged cross-sectional view of a portion where a fixed scroll of a modified scroll compressor according to the second embodiment is shrink-fitted to a main shell. In the configuration of FIG. 8, the second partial inner wall surface 2ab is flush with the second partial inner wall surface 2d, but in this modified example, the second partial inner wall surface 2ab is located between the first partial inner wall surface 2a and the second partial inner wall surface 2d in the radial direction. With this configuration, the first positioning surface 2c is divided into a first partial positioning surface 2ca on the first partial inner wall surface 2aa side and a second partial positioning surface 2cb on the second partial inner wall surface 2ab side. A recess 2ga for improving positioning accuracy is formed in the first partial positioning surface 2ca, and a recess 2gb for improving positioning accuracy is formed in the second partial positioning surface 2cb.

[0086] The fixed scroll 4 is positioned such that the surface of the other end side L of the first shrink-fitted portion 4c contacts the first portion positioning surface 2ca, which is a step portion of the first inner wall surface 2a, and the surface of the other end side L of the second shrink-fitted portion 4d contacts the second portion positioning surface 2cb. The first shrink-fitted portion 4c of the fixed scroll 4 is shrink-fitted to the first portion inner wall surface 2aa, and the second shrink-fitted portion 4d is shrink-fitted to the second portion inner wall surface 2ab. That is, although the shape of the inner wall surface of the main shell 2 is different from that of the first embodiment, the scroll compressor of the modified example is fixed to the main shell 2 in the same manner as the first embodiment. That is, in the scroll compressor of the modified example, the fixed scroll 4 is fixed to the main shell 2 by shrink-fitting the first shrink-fitted portion 4c and the second shrink-fitted portion 4d to the first inner wall surface 2a with the fixed scroll 4 positioned on the first positioning surface 2c.

[0087] Here, the relationship in size between the inner diameter of the main shell 2 and the outer diameter of the shrink-fitted portion of the fixed scroll 4 in the second embodiment will be described with reference to the following FIG.

[0088] FIG. 10 is an explanatory diagram of the relationship between the inner diameter of the main shell of the scroll compressor according to the second embodiment and the outer diameter of the shrink-fitted portion of the fixed scroll. Note that FIG. 10 is a diagram for explaining the position of each dimension of r1 to r5, and does not accurately show the shape and size. r1 is the inner diameter of the first partial inner wall surface 2aa of the first inner wall surface 2a, and r2 is the inner diameter of the second partial inner wall surface 2d. r3 is the outer diameter of the first portion 40 of the fixed base plate 4a, and r4 is the outer diameter of the second portion 41 of the fixed base plate 4a. r5 is the inner diameter of the second partial inner wall surface 2ab of the first inner wall surface 2a. In the second embodiment, the relationships r3>r1≧r5 and r4>r5≧r2 are established. In the scroll compressor according to the second embodiment, r1 to r5 are designed in consideration of this relationship, the strength of the fixed scroll 4, the retention force of the shrink fit, and interference with other parts.

[0089] According to the second embodiment, the same effect as that of the first embodiment can be obtained. In the second embodiment, the fixed base plate 4a of the fixed scroll 4 has a first portion 40 with an outer diameter larger than that of the second portion 41. In this configuration, the surface of the one end side U of the fixed scroll 4 can be used more widely than when the outer diameter of the first portion 40 is smaller than that of the second portion 41. The discharge valve 11 is provided on the surface of the one end side U of the fixed scroll 4, but it is also possible to provide a component such as a muffler that reduces the opening and closing sound of the discharge valve 11. Therefore, the surface of the one end side U of the fixed scroll 4 can be used more widely, thereby increasing the degree of freedom of the components.

[0090] Embodiment 3 The third embodiment relates to a technique for improving the shrink-fit holding force of the fixed scroll 4 to the main shell 2. The following description will focus on configurations of the third embodiment that are different from the first and second embodiments, and configurations not described in the third embodiment are the same as those in the first and second embodiments.

[0091] Fig. 11 is a schematic enlarged sectional view of a portion where a fixed scroll of a scroll compressor according to embodiment 3 is shrink-fitted to a main shell. Fig. 12 is a plan view of a fixed scroll of the scroll compressor according to embodiment 3. Fig. 13 is a plan view of a first modified example of the fixed scroll of the scroll compressor according to embodiment 3. Fig. 14 is a plan view of a second modified example of the fixed scroll of the scroll compressor according to embodiment 3.

[0092] The scroll compressor of the third embodiment has a configuration in which a plurality of bypass holes 4f having a circular cross section penetrating in the axial direction are provided in the first shrink-fitted portion 4c of the fixed scroll 4 as shown in Figs. 11 and 12. The bypass holes 4f are provided in the first shrink-fitted portion 4c on the side of the first shrink-fitted portion 4c and the second shrink-fitted portion 4d that is farther from the fixed scroll body 4b in the axial direction. The plurality of bypass holes 4f are formed at equal intervals in the circumferential direction as shown in Figs. 12 to 14. The bypass holes 4f communicate the discharge space 16a and the middle space 4ab. The cross-sectional shape of the bypass holes 4f is not limited to the circular shape shown in Fig. 12, and may be, for example, an arc shape as shown in Figs. 13 and 14. The bypass holes 4f may be formed inward from the outer circumferential surface of the first shrink-fitted portion 4c as shown in Figs. 12 and 13, or may be formed on the outer circumferential surface of the first shrink-fitted portion 4c as shown in Fig. 14. In short, the bypass hole 4f only needs to be configured to communicate the intermediate space 4ab with the discharge space 16a.

[0093] With the above-mentioned configuration, the discharge space 16a communicates with the middle space 4ab via the bypass hole 4f, and the high pressure in the discharge space 16a is introduced into the middle space 4ab, making the middle space 4ab a high-pressure space. By making the middle space 4ab a high-pressure space, the second shrink-fit portion 4d is pressed against the first positioning surface 2c as shown by the arrow in Fig. 11, and the holding force of the fixed scroll 4 to the main shell 2 is improved.

[0094] According to the third embodiment, the same effects as those of the first and second embodiments can be obtained, and the bypass hole 4f provided in the first shrink-fit portion 4c improves the holding force of the fixed scroll 4 to the main shell 2. The number of bypass holes 4f is not limited to multiple, and may be one. However, from the viewpoint of applying high pressure evenly to the fixed scroll 4, it is preferable that the scroll compressor has multiple bypass holes 4f formed at equal intervals in the circumferential direction.

[0095] In the above-mentioned first to third embodiments, the vertical scroll compressor has been described, but the present disclosure can also be applied to a horizontal scroll compressor. In this case, the horizontal scroll compressor can also be viewed with the main frame as a reference, with the side where the compression mechanism is provided being one end side and the side where the drive mechanism is provided being the other end side. In addition, the present disclosure is not limited to low-pressure shell type scroll compressors, but can also be applied to high-pressure shell type scroll compressors in which the inside of the shell is filled with refrigerant compressed by the compression mechanism. [Explanation of symbols]

[0096] 1 shell, 2 main shell, 2a first inner wall surface, 2aa first portion inner wall surface, 2ab second part inner wall surface, 2b first protrusion, 2c first positioning surface, 2ca first part positioning surface, 2cb second part positioning surface, 2d second inner wall surface, 2e second protrusion, 2f second positioning surface, 2g recess, 2ga recess, 2gb recess, 2h recess, 3 main frame, 3a main body, 3b main bearing, 3c oil return pipe, 3d accommodation space, 3e flat surface, 3f suction port, 3g Oldham accommodation section, 3h first Oldham groove, 3i shaft hole, 4 fixed scroll, 4a fixed base plate, 4aa groove, 4ab middle space, 4b fixed scroll, 4c first shrink fit section, 4d second shrink fit section, 4e center of gravity, 4f bypass hole, 4g discharge port, 4h compression chamber, 5 swing scroll, 5a swing base plate, 5b oscillating scroll, 5c cylindrical portion, 5d second Oldham groove, 5e sliding surface, 5f side surface, 6 compression mechanism portion, 7 oil pump, 8 Oldham ring, 8a ring portion, 8b first key portion, 8c second key portion, 9 bush, 9a slider, 9b balance weight, 9c weight portion, 10 rotating shaft, 10a main shaft portion, 10b eccentric shaft portion, 10c first balancer, 10d second balancer, 11 discharge valve, 12 lower shell, 13 thrust plate, 14 drive mechanism portion, 14a stator, 14b rotor, 15 subframe, 15a auxiliary bearing portion, 16 upper shell, 16a discharge space, 17 power supply portion, 17a cover, 17b power supply terminal, 17c wiring, 18 suction pipe, 19 discharge pipe, 20 Oil passage, 21 Refrigerant intake space, 30 neutral axis, 31 first load line, 32 second load line, 40 first section, 41 second section, 42 intermediate section, 50 dotted line, 51 dotted line.

Claims

1. A frame for holding an orbiting scroll; A fixed scroll disposed opposite the orbiting scroll; A rotation shaft that rotates the orbiting scroll; a shell that accommodates the orbiting scroll, the frame, the fixed scroll, and the rotating shaft; the shell has a first inner wall surface and a first protrusion protruding from the first inner wall surface to position the fixed scroll, the fixed scroll has a fixed base plate and a fixed scroll body formed protruding from the fixed base plate, and is fixed to the first inner wall surface by a shrink-fit portion on an outer periphery of the fixed base plate in a state where the fixed scroll is positioned by the first protruding portion, The shrink-fitted portion includes a first shrink-fitted portion and a second shrink-fitted portion that are spaced apart from each other across a neutral axis that passes through the center of gravity of the fixed scroll and is perpendicular to the rotation shaft in the axial direction of the rotation shaft, and have a constant length in the axial direction, The fixed scroll is fixed to the first inner wall surface at two locations, the first shrink-fit portion and the second shrink-fit portion.

2. a groove extending in a circumferential direction is formed on an outer peripheral surface of the fixed scroll, and an intermediate space is formed between the outer peripheral surface of the fixed scroll and the first inner wall surface of the shell, The scroll compressor according to claim 1 , wherein the first shrink-fitted portion and the second shrink-fitted portion are formed on both sides of the intermediate space in the axial direction.

3. The fixed scroll forms a compression chamber together with the orbiting scroll, Within the shell, a space on the opposite side of the fixed scroll from the orbiting scroll is a discharge space from which the refrigerant compressed in the compression chamber is discharged, 3. The scroll compressor according to claim 2, wherein the first shrink-fitted portion, which is one of the first shrink-fitted portion and the second shrink-fitted portion and is located away from the fixed scroll in the axial direction, has a bypass hole formed therein, which penetrates therethrough in the axial direction and communicates between the discharge space and the intermediate space.

4. 4. The scroll compressor according to claim 2, wherein the intermediate space overlaps with the fixed scroll body of the fixed scroll when viewed in the axial direction.

5. The fixed base plate of the fixed scroll has a first portion having a plate shape perpendicular to the axial direction and the first shrink-fit portion, and a second portion having a plate shape perpendicular to the axial direction and the second shrink-fit portion, The scroll compressor according to any one of claims 1 to 4, wherein an outer diameter of the first portion having the first shrink-fit portion that is away from the fixed scroll body in the axial direction out of the first shrink-fit portion and the second shrink-fit portion is equal to or larger than an outer diameter of the second portion.

6. The scroll compressor according to any one of claims 1 to 5, wherein the first inner wall surface is formed in a stepped shape with one step, and the first shrink-fitted portion, which is one of the first shrink-fitted portion and the second shrink-fitted portion and which is farther from the fixed scroll body in the axial direction, abuts against the stepped portion.

7. The shell further has a second inner wall surface and a second protrusion protruding from the second inner wall surface and positioning the frame, The scroll compressor according to any one of claims 1 to 6, wherein the frame is fixed to the second inner wall surface in a state where the frame is positioned at the second protruding portion.

Images