JP2017044186A - Scroll compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a scroll compressor capable of suppressing the deformation of a movable scroll during operation by removing tensile residual stress on the movable scroll shortly and inexpensively.SOLUTION: The scroll compressor includes a casing, a fixed scroll, a movable scroll 26, and a crank shaft. The movable scroll 26 is formed of spheroidal graphite cast iron. The movable scroll 26 has a second panel 26a, a second lap 26b, and an upper end bearing 26c. The second lap 26b extends from a first main surface 26d of the second panel 26a. The upper end bearing 26c extends from a second main surface 26e of the second panel 26a, where the crank shaft is fitted. At least part of the second surface 26e is subjected to shot peening treatment so that compression residual stress works on the second panel 26a. The compression residual stress is the one that works along the radial direction of the second main surface 26e toward the center of the second main surface 26e.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a scroll compressor.

  A scroll compressor used in a refrigeration apparatus or the like compresses refrigerant circulating in a refrigerant circuit. The scroll compressor includes a fixed scroll and a movable scroll. Each of the fixed scroll and the movable scroll has an end plate and a spiral wrap attached to the main surface of the end plate. The movable scroll wrap meshes with the fixed scroll wrap to form a compression chamber in which the refrigerant gas is compressed. The scroll compressor revolves the movable scroll by the rotation of the crankshaft and changes the volume of the compression chamber to compress the refrigerant. The movable scroll has a bearing into which the crankshaft is fitted. The movable scroll bearing is attached to the central portion of the main surface opposite to the main surface to which the wrap is attached.

  Conventionally, spheroidal graphite cast iron such as FCD600 has been used as a material for the movable scroll. Since spheroidal graphite cast iron has higher strength than gray cast iron such as FC250, the size of the movable scroll can be reduced and the size of the scroll compressor can be reduced. However, when spheroidal graphite cast iron is used as the material of the movable scroll having a complicated shape, tensile residual stress tends to be generated on the surface of the end plate due to the difference in the solidification rate and cooling rate between the lap and the bearing in the casting process. . For this reason, the tensile residual stress acting on the movable scroll formed of spheroidal graphite cast iron tends to be larger than the tensile residual stress acting on the movable scroll formed of gray cast iron. Here, the tensile residual stress is a stress acting in a direction away from each other along the radial direction of the end plate. Further, during operation of the scroll compressor, a force orthogonal to the main surface of the end plate acts on the movable scroll from the bearing toward the lap. This force and tensile residual stress cause the movable scroll to deform during operation of the scroll compressor.

  Conventionally, in order to suppress the deformation of the movable scroll formed of spheroidal graphite cast iron, various methods for removing the tensile residual stress acting on the movable scroll have been used. For example, Patent Document 1 (Japanese Patent Laid-Open No. 62-164819) discloses a method in which a movable scroll is held at 540 ° C. to 570 ° C. for 4 hours to 8 hours, cooled to 350 ° C., and then air cooled. ing. In Patent Document 2 (Japanese Patent Laid-Open No. 54-133420), the movable scroll is held at 850 ° C. to 1000 ° C. for 4 hours or less, then rapidly cooled to 200 ° C. to 400 ° C., and held at that temperature for 30 minutes or more. Thereafter, a method of performing shot peening is disclosed. In Patent Document 3 (Japanese Patent Laid-Open No. 2012-115925), first, second and third shot peening treatments are performed using shot materials having different particle diameters after heat-treating the movable scroll at 800 ° C. to 950 ° C. Is disclosed. However, these methods have a problem that the time and cost required for heat treatment and shot peening are large.

  An object of the present invention is to provide a scroll compressor capable of removing tensile residual stress acting on a movable scroll in a short time and at a low cost and suppressing deformation of the movable scroll during operation.

  A scroll compressor according to a first aspect of the present invention includes a casing, a fixed scroll, a movable scroll, and a crankshaft. The fixed scroll, the movable scroll and the crankshaft are accommodated in the casing. The movable scroll is formed of spheroidal graphite cast iron. The movable scroll meshes with the fixed scroll to compress the refrigerant. The crankshaft drives the movable scroll. The movable scroll includes a disk-shaped movable mirror plate, a spiral movable wrap, and a cylindrical portion. The movable end plate has a first main surface and a second main surface. The movable wrap extends from the first main surface. The cylindrical portion extends from the second main surface, and a crankshaft is fitted therein. At least a part of the second main surface is shot peened so that compressive residual stress acts on the movable end plate. The compressive residual stress is a stress that acts toward the center of the second main surface along the radial direction of the second main surface.

  In this scroll compressor, the compressive residual stress can be applied to the movable end plate only by subjecting the second main surface to shot peening without heat-treating the movable scroll. Therefore, this scroll compressor can remove the tensile residual stress acting on the movable scroll in a short time and at a low cost, and can suppress the deformation of the movable scroll during operation.

  A scroll compressor according to a second aspect of the present invention is the scroll compressor according to the first aspect, wherein the compressive residual stress is a stress having a negative average residual stress value. The average residual stress value is a plurality of intermediate points located at equal intervals along the circumferential direction of the second main surface with respect to the radial intermediate point between the outer edge of the cylindrical portion and the outer edge of the second main surface. It is the average of the residual stress value which acts in each of these. The residual stress value is negative when the stress from the outer edge of the second main surface in the radial direction acts on the movable mirror plate, and the stress from the center of the second main surface in the radial direction toward the outer edge is movable. Positive when acting on

  In this scroll compressor, the second main surface is shot peened so that radial stress from the outer edge of the second main surface toward the center acts at a plurality of intermediate points on the second main surface. Therefore, this scroll compressor can remove the tensile residual stress acting on the movable scroll in a short time and at a low cost, and can suppress the deformation of the movable scroll during operation.

  The scroll compressor which concerns on the 3rd viewpoint of this invention is a scroll compressor which concerns on a 1st viewpoint or a 2nd viewpoint, Comprising: The whole 2nd main surface is shot-peened.

  In this scroll compressor, the tensile residual stress acting on the movable scroll is effectively removed by performing shot peening on the entire second main surface. Therefore, this scroll compressor can effectively suppress the deformation of the movable scroll during operation.

  The scroll compressor which concerns on the 4th viewpoint of this invention is a scroll compressor which concerns on any one of the 1st thru | or 3rd viewpoint, Comprising: The ratio of the thickness of a movable wrap and the thickness of a movable end plate is 10 or less It is.

  In this scroll compressor, the thickness of the movable end plate is larger than the thickness of the movable wrap. Therefore, this scroll compressor has high strength of the movable end plate, and can effectively suppress deformation of the movable scroll during operation.

  The scroll compressor which concerns on the 5th viewpoint of this invention is a scroll compressor which concerns on any one of the 1st thru | or 4th viewpoint, Comprising: Spheroidal graphite cast iron is FCD600.

  In this scroll compressor, the movable scroll is formed of FCD600, which is spheroidal graphite cast iron having higher strength than cast iron such as FC250. Therefore, this scroll compressor can effectively suppress the deformation of the movable scroll during operation.

  The scroll compressor according to the present invention can remove the tensile residual stress acting on the movable scroll in a short time and at low cost, and can suppress the deformation of the movable scroll during operation.

It is a longitudinal cross-sectional view of the scroll compressor when the casing is in a basic posture according to the embodiment. It is a bottom view of a fixed scroll. It is a top view of a movable scroll. It is a bottom view of the fixed scroll in which the position of the second wrap of the movable scroll and the compression chamber are shown. It is a bottom view of a movable scroll. It is sectional drawing of the movable scroll cut | disconnected along VI-VI of FIG. It is a bottom view of a movable scroll as a comparative example. It is sectional drawing of the movable scroll cut | disconnected along VIII-VIII of FIG. It is a top view of the movable scroll based on an Example. 10 is a bottom view of a movable scroll according to Modification A. FIG.

  A scroll compressor 101 according to an embodiment of the present invention will be described with reference to the drawings. The scroll compressor 101 is used in a refrigeration apparatus such as an air conditioner. The scroll compressor 101 compresses the refrigerant gas circulating in the refrigerant circuit of the refrigeration apparatus.

(1) Configuration of Scroll Compressor The scroll compressor 101 is a compressor that compresses refrigerant using two scroll members having spiral-shaped wraps that mesh with each other. The scroll compressor 101 is a high and low pressure dome type scroll compressor.

  FIG. 1 is a longitudinal sectional view of the scroll compressor 101. The scroll compressor 101 mainly includes a casing 10, a compression mechanism 15, a housing 23, an Oldham joint 39, a drive motor 16, a lower bearing 60, a crankshaft 17, a suction pipe 19, and a discharge pipe 20. Consists of Next, each component of the scroll compressor 101 will be described.

(1-1) Casing The casing 10 includes a cylindrical body casing portion 11, a bowl-shaped upper wall section 12, and a bowl-shaped bottom wall section 13. The upper wall portion 12 is welded to the upper end portion of the trunk portion casing portion 11 in an airtight manner. The bottom wall portion 13 is welded to the lower end portion of the body casing portion 11 in an airtight manner. The casing 10 is formed of a rigid member that is unlikely to be deformed or damaged when pressure or temperature changes inside or outside the casing 10. The casing 10 is installed such that the cylindrical axial direction of the body casing portion 11 is along the vertical direction.

  Inside the casing 10, a compression mechanism 15, a housing 23 disposed below the compression mechanism 15, a drive motor 16 disposed below the housing 23, and a crankshaft 17 disposed to extend in the vertical direction. Etc. are housed. A suction pipe 19 and a discharge pipe 20 are welded to the wall portion of the casing 10 in an airtight manner.

  An oil sump space 10 a in which lubricating oil is stored is formed at the bottom of the casing 10. Lubricating oil is used to keep the lubricity of sliding parts such as the compression mechanism 15 good during the operation of the scroll compressor 101.

(1-2) Compression Mechanism The compression mechanism 15 is housed inside the casing 10, sucks and compresses low-temperature and low-pressure refrigerant gas, and discharges high-temperature and high-pressure refrigerant gas (hereinafter referred to as “compressed refrigerant”). . The compression mechanism 15 is mainly composed of a fixed scroll 24 and a movable scroll 26. The fixed scroll 24 is fixed with respect to the casing 10. The movable scroll 26 performs a revolving motion with respect to the fixed scroll 24. FIG. 2 is a bottom view of the fixed scroll 24 viewed along the vertical direction. FIG. 3 is a top view of the movable scroll 26 viewed along the vertical direction.

  The fixed scroll 24 is formed from gray cast iron, spheroidal graphite cast iron, aluminum, or the like. The movable scroll 26 is formed from spheroidal graphite cast iron. In the present embodiment, the spheroidal graphite cast iron used for the movable scroll 26 is FCD600.

(1-2-1) Fixed Scroll The fixed scroll 24 includes a first end plate 24a and a spiral-shaped first wrap 24b formed upright on the first end plate 24a. A main suction hole 24c is formed in the first end plate 24a. The main suction hole 24c is a space that connects the suction pipe 19 and a compression chamber 40 described later. The main suction hole 24 c forms a suction space for introducing a low-temperature and low-pressure refrigerant gas from the suction pipe 19 into the compression chamber 40.

  A discharge hole 41 is formed in the central portion of the first end plate 24a, and an enlarged recess 42 communicating with the discharge hole 41 is formed on the upper surface of the first end plate 24a. The enlarged recess 42 is a space recessed in the upper surface of the first end plate 24a. A lid 44 is fixed to the upper surface of the fixed scroll 24 with bolts 44 a so as to close the enlarged recess 42. The fixed scroll 24 and the lid 44 are tightly sealed through a gasket (not shown). A muffler space 45 that silences the operation sound of the compression mechanism 15 is formed by covering the enlarged recess 42 with the lid 44. The fixed scroll 24 is formed with a first compressed refrigerant channel 46 that communicates with the muffler space 45 and opens on the lower surface of the fixed scroll 24. As shown in FIG. 2, a C-shaped oil groove 24e is formed on the lower surface of the first end plate 24a.

(1-2-2) Movable Scroll The movable scroll 26 includes a disk-shaped second end plate 26a, a spiral second wrap 26b, and a cylindrical upper end bearing 26c. The second end plate 26a has a first main surface 26d and a second main surface 26e. The first main surface 26d is the upper main surface of the second end plate 26a. The second main surface 26e is a lower main surface of the second end plate 26a. The second wrap 26b is formed upright from the first main surface 26d. The upper end bearing 26c is formed upright from the central portion of the second main surface 26e. The movable scroll 26 has an oil supply hole 63 formed therein. The oil supply pore 63 communicates the outer peripheral portion of the first main surface 26d and the space inside the upper end bearing 26c at the center portion of the second main surface 26e.

  The fixed scroll 24 and the movable scroll 26 are surrounded by the first end plate 24a, the first wrap 24b, the second end plate 26a, and the second wrap 26b when the first wrap 24b and the second wrap 26b are engaged with each other. A compression chamber 40 that is a space is formed. The volume of the compression chamber 40 is gradually reduced by the revolving motion of the movable scroll 26. During the revolution of the movable scroll 26, the lower surfaces of the first end plate 24 a and the first wrap 24 b of the fixed scroll 24 slide with the upper surfaces of the second end plate 26 a and the second wrap 26 b of the movable scroll 26. Hereinafter, the surface of the fixed scroll 24 that slides with the movable scroll 26 is referred to as a thrust sliding surface 24d.

  FIG. 4 is a bottom view of the fixed scroll 24 in which the position of the second lap 26b of the movable scroll 26 and the compression chamber 40 are shown. In FIG. 4, the hatched area represents the thrust sliding surface 24 d of the fixed scroll 24. In FIG. 4, the outer edge of the thrust sliding surface 24 d represents the locus of the outer edge of the second end plate 26 a of the revolving movable scroll 26. As shown in FIG. 4, the oil groove 24e of the fixed scroll 24 is formed on the lower surface of the first end plate 24a so as to fit in the thrust sliding surface 24d.

  The second main surface 26e of the second end plate 26a is shot peened. The shot peening process is an injection processing process in which countless minute steel balls are projected toward the second main surface 26e, and the steel balls collide with the second main surface 26e at high speed. By the shot peening process, the second main surface 26e is plastically deformed so that innumerable minute recesses are formed on the second main surface 26e. As a result, the second end plate 26a is cured, and compressive residual stress is applied to the second end plate 26a.

  The diameter of the steel ball used in the shot peening process is 0.05 mm to 4 mm. The speed of the steel ball projected toward the second main surface 26e is 10 m / s to 200 m / s. An incident angle, which is an angle between the normal line of the second main surface 26e and the projection direction of the steel ball, is 40 ° to 90 °.

  FIG. 5 is a bottom view of the movable scroll 26. 6 is a cross-sectional view of the movable scroll 26 cut along VI-VI in FIG. 5 and 6, the stress acting on the movable scroll 26 is indicated by an arrow. In FIG. 5, the area of the second main surface 26e that has been shot peened is shown as a hatched area.

  As shown in FIGS. 5 and 6, the second main surface 26e is shot peened so that the compressive residual stress F1 acts on the second end plate 26a. The compressive residual stress F1 is a stress acting from the outer periphery of the second main surface 26e toward the center along the radial direction of the second main surface 26e.

  The compressive residual stress F1 acting on the second end plate 26a by the shot peening process of the second main surface 26e is a stress having a negative average residual stress value. The average residual stress value is an average of residual stress values acting at each of the intermediate points P1 to P4 shown in FIG. The intermediate points P1 to P4 are intermediate points in the radial direction of the second main surface 26e between the outer edge of the upper end bearing 26c and the outer edge of the second main surface 26e. The intermediate points P1 to P4 are located at equal intervals along the circumferential direction of the second main surface 26e. The number of intermediate points is arbitrary. The residual stress value is a negative value when a stress from the outer edge of the second main surface 26e toward the center acts on the second end plate 26a in the radial direction of the second main surface 26e. The residual stress value is a positive value when the stress from the center of the second main surface 26e toward the outer edge acts on the second end plate 26a in the radial direction of the second main surface 26e.

  The ratio between the thickness T1 of the second wrap 26b and the thickness T2 of the second end plate 26a is 10 or less. FIG. 6 shows thicknesses T1 and T2. When the thicknesses T1 and T2 are different depending on the position, the maximum values of the thicknesses T1 and T2 are used as shown in FIG.

(1-3) Housing The housing 23 is disposed below the compression mechanism 15. The outer peripheral surface of the housing 23 is joined to the inner peripheral surface of the body casing portion 11 in an airtight manner. Thereby, the internal space of the casing 10 is partitioned into a high-pressure space S <b> 1 below the housing 23 and an upper space S <b> 2 that is a space above the housing 23. The housing 23 mounts a fixed scroll 24 and holds a movable scroll 26 together with the fixed scroll 24. A second compressed refrigerant channel 48 is formed through the outer periphery of the housing 23 in the vertical direction. The second compressed refrigerant channel 48 communicates with the first compressed refrigerant channel 46 on the upper surface of the housing 23, and communicates with the high-pressure space S <b> 1 on the lower surface of the housing 23.

  A crank chamber S <b> 3 is recessed in the upper surface of the housing 23. A housing through hole 31 is formed in the housing 23. The housing through hole 31 penetrates the housing 23 in the vertical direction from the center of the bottom surface of the crank chamber S3 to the center of the lower surface of the housing 23. Hereinafter, a portion that is a part of the housing 23 and in which the housing through hole 31 is formed is referred to as an upper bearing 32. The housing 23 is formed with an oil return passage 23a that connects the high-pressure space S1 near the inner surface of the casing 10 and the crank chamber S3.

(1-4) Oldham Joint The Oldham Joint 39 is an annular member installed between the movable scroll 26 and the housing 23. The Oldham coupling 39 is a member for preventing rotation of the orbiting scroll 26 that is revolving.

(1-5) Drive Motor The drive motor 16 is a brushless DC motor disposed below the housing 23. The drive motor 16 mainly includes a stator 51 that is fixed to the inner surface of the casing 10 and a rotor 52 that is disposed with an air gap provided inside the stator 51.

  The outer peripheral surface of the stator 51 is provided with a plurality of core cut portions that are notched from the upper end surface of the stator 51 to the lower end surface and at a predetermined interval in the circumferential direction. The core cut portion forms a motor cooling passage 55 that extends in the vertical direction between the body casing portion 11 and the stator 51.

  The rotor 52 is connected to the crankshaft 17 that passes through the center of rotation in the vertical direction. The rotor 52 is connected to the compression mechanism 15 via the crankshaft 17.

(1-6) Lower Bearing The lower bearing 60 is disposed below the drive motor 16. The outer peripheral surface of the lower bearing 60 is joined to the inner surface of the casing 10 in an airtight manner. The lower bearing 60 supports the crankshaft 17. An oil separation plate 65 is attached to the upper end of the lower bearing 60. The oil separation plate 65 is a flat plate member accommodated in the casing 10. The oil separation plate 65 is fixed to the upper end surface of the lower bearing 60.

(1-7) Crankshaft The crankshaft 17 is accommodated in the casing 10. The crankshaft 17 is arranged so that its axial direction is along the vertical direction. The crankshaft 17 has a shape in which the axial center of the upper end portion is slightly eccentric with respect to the axial center of the portion excluding the upper end portion. The crankshaft 17 has a balance weight 18. The balance weight 18 is fixed in close contact with the crankshaft 17 at a height position below the housing 23 and above the drive motor 16.

  The crankshaft 17 passes through the rotation center of the rotor 52 in the vertical direction and is connected to the rotor 52. The crankshaft 17 is connected to the movable scroll 26 by fitting the upper end of the crankshaft 17 into the upper end bearing 26c. The crankshaft 17 is supported by the upper bearing 32 and the lower bearing 60.

  The crankshaft 17 has a main oil supply passage 61 extending in the axial direction thereof. The upper end of the main oil supply passage 61 communicates with an oil chamber 67 formed by the upper end surface of the crankshaft 17 and the second main surface 26e. The oil chamber 67 communicates with the thrust sliding surface 24d and the oil groove 24e via the oil supply hole 63 of the second end plate 26a, and finally communicates with the low pressure space S2 via the compression chamber 40. The lower end of the main oil supply passage 61 communicates with the oil sump space 10a.

  The crankshaft 17 has a first sub oil supply path 61 a, a second sub oil supply path 61 b, and a third sub oil supply path 61 c that branch from the main oil supply path 61. The first sub oil supply path 61a, the second sub oil supply path 61b, and the third sub oil supply path 61c extend in the horizontal direction. The first sub oil supply passage 61 a is open to the sliding surface between the crankshaft 17 and the upper end bearing 26 c of the movable scroll 26. The second sub oil supply passage 61 b opens in the sliding surface between the crankshaft 17 and the upper bearing 32 of the housing 23. The third sub oil supply passage 61 c is open on the sliding surface between the crankshaft 17 and the lower bearing 60.

(1-8) Suction Pipe The suction pipe 19 is a pipe for introducing the refrigerant of the refrigerant circuit from the outside of the casing 10 to the compression mechanism 15. The suction pipe 19 is fitted into the upper wall portion 12 of the casing 10 in an airtight manner. The suction pipe 19 penetrates the upper space S2 in the vertical direction. The inner end of the suction pipe 19 is fitted in the main suction hole 24 c of the fixed scroll 24. The inner end of the suction pipe 19 is the end of the suction pipe 19 in the internal space of the casing 10.

(1-9) Discharge Pipe The discharge pipe 20 is a pipe for discharging the compressed refrigerant from the high-pressure space S1 to the outside of the casing 10. The discharge pipe 20 is fitted in the body casing part 11 of the casing 10 in an airtight manner. The discharge pipe 20 penetrates the high-pressure space S1 in the horizontal direction. The opening 20 a of the discharge pipe 20 in the casing 10 is located in the vicinity of the housing 23.

(2) Operation of Scroll Compressor The operation of the scroll compressor 101 according to this embodiment will be described. Initially, the flow of the refrigerant | coolant which circulates through a refrigerant circuit provided with the scroll compressor 101 is demonstrated. Next, the flow of the lubricating oil inside the scroll compressor 101 will be described.

(2-1) Flow of refrigerant First, when the drive motor 16 is driven, the rotor 52 rotates. As a result, the crankshaft 17 fixed to the rotor 52 rotates. The rotational motion of the crankshaft 17 is transmitted to the movable scroll 26 via the upper end bearing 26c. The axis of the upper end portion of the crankshaft 17 is eccentric with respect to the axis of rotation of the crankshaft 17. The movable scroll 26 is engaged with the housing 23 via an Oldham joint 39. Thereby, the movable scroll 26 performs a revolving motion with respect to the fixed scroll 24 without rotating.

  The low-temperature and low-pressure refrigerant before being compressed is supplied from the suction pipe 19 to the compression chamber 40 of the compression mechanism 15 via the main suction hole 24c. By the revolving motion of the movable scroll 26, the compression chamber 40 moves from the outer peripheral portion of the fixed scroll 24 toward the center portion while gradually reducing the volume. As a result, the refrigerant in the compression chamber 40 is compressed to become a compressed refrigerant. The compressed refrigerant is discharged from the discharge hole 41 to the muffler space 45, and then discharged to the high-pressure space S1 via the first compressed refrigerant channel 46 and the second compressed refrigerant channel 48. Then, the compressed refrigerant descends the motor cooling passage 55 and reaches the high pressure space S <b> 1 below the drive motor 16. Then, the compressed refrigerant reverses the flow direction and raises the air gap between the other motor cooling passage 55 and the drive motor 16. Finally, the compressed refrigerant is discharged from the discharge pipe 20 to the outside of the scroll compressor 101.

  The crank chamber S3 and the oil chamber 67 located below the movable scroll 26 communicate with the high-pressure space S1. On the other hand, the compression chamber 40 located above the movable scroll 26 is a lower pressure space than the high pressure space S1 except for the central portion communicating with the discharge hole 41. Therefore, during the operation of the scroll compressor 101, the movable scroll 26 receives a force directed upward in the vertical direction due to the pressure difference between the upper and lower spaces of the movable scroll 26 and is pressed against the fixed scroll 24.

(2-2) Flow of Lubricating Oil First, when the drive motor 16 is driven, the rotor 52 rotates, whereby the crankshaft 17 rotates. When the compression mechanism 15 is driven by the rotation of the crankshaft 17 and the compressed refrigerant is discharged into the high-pressure space S1, the pressure in the high-pressure space S1 increases. Further, the upper end of the main oil supply passage 61 communicates with the low pressure space S <b> 2 through the oil chamber 67 and the oil supply hole 63. Thereby, a differential pressure is generated between the upper end and the lower end of the main oil supply passage 61. As a result, the lubricating oil stored in the oil reservoir space 10 a is sucked into the oil supply pipe 90 by the differential pressure, and rises in the main oil supply path 61 toward the oil chamber 67.

  Most of the lubricating oil that moves up the main oil supply passage 61 is sequentially divided into the third sub oil supply passage 61c, the second sub oil supply passage 61b, and the first sub oil supply passage 61a. The lubricating oil flowing through the third sub oil supply passage 61c lubricates the sliding surfaces of the crankshaft 17 and the lower bearing 60, and then is supplied to the high pressure space S1 and returned to the oil reservoir space 10a. The lubricating oil flowing through the second auxiliary oil supply passage 61b lubricates the sliding surface between the crankshaft 17 and the upper bearing 32 of the housing 23, and then is supplied to the high-pressure space S1 and the crank chamber S3. The lubricating oil supplied to the high pressure space S1 is returned to the oil sump space 10a. The lubricating oil supplied to the crank chamber S3 is supplied to the high-pressure space S1 via the oil return passage 23a of the housing 23 and returned to the oil reservoir space 10a. The lubricating oil flowing through the first auxiliary oil supply passage 61a lubricates the sliding surface between the crankshaft 17 and the upper end bearing 26c of the movable scroll 26, and then is supplied to the crank chamber S3, and is stored in the oil reservoir via the high-pressure space S1. Returned to the space 10a.

  The lubricating oil that has moved up to the upper end in the main oil supply passage 61 and reached the oil chamber 67 flows through the oil supply holes 63 and is supplied to the oil groove 24e due to the differential pressure. Part of the lubricating oil supplied to the oil groove 24e leaks into the low pressure space S2 and the compression chamber 40 while sealing the thrust sliding surface 24d. At this time, the high-temperature and high-pressure lubricating oil heats the refrigerant gas before compression existing in the low-pressure space S2 and the compression chamber 40. The lubricating oil that has flowed into the compression chamber 40 is mixed with the compressed refrigerant in the form of minute oil droplets. The lubricating oil mixed in the compressed refrigerant is discharged from the compression chamber 40 to the high-pressure space S1 through the same path as the compressed refrigerant. Thereafter, the lubricant oil collides with the oil separation plate 65 after descending the motor cooling passage 55 together with the compressed refrigerant. The lubricating oil adhering to the oil separation plate 65 falls in the high pressure space S1 and is returned to the oil sump space 10a.

(3) Features of the scroll compressor In the scroll compressor 101 of this embodiment, the compressive residual stress F1 is applied to the second end plate 26a of the movable scroll 26 by the shot peening process of the second main surface 26e. The tensile residual stress acting on the movable scroll 26 is removed by the compressive residual stress F1, and deformation of the movable scroll 26 during operation of the scroll compressor 101 is suppressed. The reason will be described below.

  Initially, the stress which acts on the movable scroll 126 shape | molded by FCD600 which is a spheroidal graphite cast iron is demonstrated as a comparative example. FIG. 7 is a bottom view of the movable scroll 126. 8 is a cross-sectional view of the movable scroll 126 cut along VIII-VIII in FIG. The movable scroll 126 has the same shape as the movable scroll 26 and is installed at the same position as the movable scroll 26 shown in FIG.

  The movable scroll 126 includes a disk-shaped second end plate 126a, a spiral second wrap 126b, and a cylindrical upper end bearing 126c. Second end plate 126a has a first main surface 126d and a second main surface 126e. The first main surface 126d is an upper main surface of the second end plate 126a. The second main surface 126e is a lower main surface of the second end plate 126a. Second wrap 126b is formed upright from first main surface 126d. Upper end bearing 126c is formed upright from the center of second main surface 126e. 7 and 8, the stress acting on the movable scroll 126 is indicated by an arrow.

  In the movable scroll 26 of the present embodiment, the second main surface 26e is shot peened, but in the movable scroll 126 of the comparative example, the second main surface 126e is not shot peened. The movable scroll 126 is not heat-treated after molding. That is, the movable scroll 126 is not subjected to a process for removing the tensile residual stress. Therefore, as shown in FIGS. 7 and 8, a tensile residual stress F11 is applied to the second end plate 126a. The tensile residual stress F11 is a stress acting from the center of the second end plate 126a toward the outer edge along the radial direction of the main surface of the second end plate 126a. The tensile residual stress F11 is mainly caused by a difference in the solidification rate or the cooling rate between the second lap 126b and the upper end bearing 126c when the movable scroll 126 is formed.

  Further, during the operation of the scroll compressor, the movable scroll 126 receives the pressing force F12 directed upward in the vertical direction due to the pressure difference, as described above. Therefore, during operation of the scroll compressor, the second end plate 126a of the movable scroll 126 receives a resultant force of the tensile residual stress F11 and the pressing force F12. This resultant force is a force that deforms the second end plate 126a so as to protrude upward in the vertical direction.

  On the other hand, as shown in FIGS. 5 and 6, compressive residual stress F1 is applied to the second end plate 26a of the movable scroll 26 of the present embodiment by shot peening treatment of the second main surface 26e. The compressive residual stress F1 acts from the outer edge of the second end plate 26a toward the center along the radial direction of the main surface of the second end plate 26a. That is, the compressive residual stress F1 acting on the second end plate 26a is a force in the direction opposite to the tensile residual stress F11 acting on the second end plate 126a as a comparative example. Therefore, a force corresponding to the resultant force of the tensile residual stress F11 and the pressing force F12 shown in FIG. That is, the compressive residual stress F1 acting on the second end plate 26a of the movable scroll 26 has an effect of suppressing deformation of the second end plate 26a protruding upward in the vertical direction. Thereby, the deformation | transformation of the movable scroll 26 during the driving | operation of the scroll compressor 101 is suppressed.

  In the present embodiment, in order to suppress the deformation of the movable scroll 26, only the shot peening process of the second main surface 26e is performed without heat-treating the movable scroll 26 after the movable scroll 26 is formed. The compressive residual stress F1 is applied. The heat treatment of the movable scroll 26 is a process of removing the tensile residual stress acting on the movable scroll 26 by heating the movable scroll 26 and maintaining the high temperature state for a long time and then gradually cooling it. The heat treatment of the movable scroll 26 takes a long time and is expensive. However, in the present embodiment, the tensile residual stress acting on the movable scroll 26 can be removed in a short time and at a low cost by performing only the shot peening process on the second main surface 26e. Thereby, the deformation | transformation of the movable scroll 26 at the time of the driving | operation of the scroll compressor 101 is suppressed.

  The ratio between the thickness T1 of the second wrap 26b and the thickness T2 of the second end plate 26a is 10 or less. As the ratio between T1 and T2 is smaller, the thickness T2 of the second end plate 26a is larger than the thickness T1 of the second wrap 26b, and the strength of the second end plate 26a is increased. Therefore, the second end plate 26a is deformed. Is suppressed more effectively. Therefore, deformation of the movable scroll 26 is effectively suppressed during the operation of the scroll compressor 101.

  Note that when the movable scroll is formed of gray cast iron such as FC250, compressive residual stress may act on the movable scroll without heat treatment of the movable scroll. However, the movable scroll formed of gray cast iron has a lower strength than the movable scroll 26 of the present embodiment formed of FCD600, which is spheroidal graphite cast iron. Since the movable scroll 26 is formed of FCD600 and compressive residual stress F1 is applied, the movable scroll 26 has high strength and is difficult to be deformed as compared with a movable scroll formed of gray cast iron.

  As described above, the scroll compressor 101 can remove the tensile residual stress acting on the movable scroll 26 in a short time and at low cost, and can suppress the deformation of the movable scroll 26 during operation.

(4) Example Next, the measurement result of a residual stress and the measurement result of a shape change regarding the movable scroll used for a scroll compressor are demonstrated. In this example, measurement was performed on three types of movable scrolls. Hereinafter, the three types of movable scrolls are referred to as an example, comparative example 1, and comparative example 2, respectively. The three types of movable scrolls have a common shape and dimensions.

  An example is the movable scroll 26 of the embodiment. In other words, the embodiment is a movable scroll that is formed of FCD600, which is spheroidal graphite cast iron, and the lower main surface of the end plate (the surface corresponding to the second main surface 26e) is shot peened. Comparative Example 1 is a movable scroll that is formed of FCD600 and is not subjected to heat treatment and shot peening treatment. Comparative Example 2 is a movable scroll that is formed of FC250, which is gray cast iron, and is not subjected to heat treatment and shot peening treatment. Tables 1 and 2 below show the measurement results of three types of movable scrolls.

  Table 1 is a table relating to the measurement result of the residual stress of each movable scroll. Table 1 lists the residual stress values measured at the same positions as the four intermediate points P1 to P4 shown in FIG. 5 and the average values thereof.

  Table 2 is a table regarding the measurement result of the shape change of each movable scroll. The shape change was measured by operating a scroll compressor provided with each movable scroll. The operating conditions of the scroll compressor are a high pressure space pressure of 4.4 MPa, a low pressure space pressure of 0.4 MPa, a rotation speed of 75 rps, and an operation time of 75 hours. The bottom surface position, which is the height position of the upper main surface (the surface corresponding to the first main surface 26d) of the end plate of the movable scroll, is measured before and after the operation of the compressor, and the bottom surface due to the operation of the scroll compressor. The amount of change in position was determined. The parameter representing the change in the shape of the movable scroll is the amount of change in the bottom surface position. The larger the absolute value of the change amount of the bottom surface position, the more the shape of the movable scroll changes. FIG. 9 is a top view of the movable scroll. FIG. 9 shows measurement regions R1 to R4 of the bottom surface position.

  From Table 1, the tensile residual stress acts on the movable scroll of Comparative Example 1, and the compressive residual stress acts on the movable scroll of Example and Comparative Example 2. That is, in the movable scroll 26 of the embodiment, it was confirmed that the tensile residual stress was removed and the compressive residual stress was applied by the shot peening process of the second main surface 26e.

  From Table 2, the amount of change in the bottom surface position of the movable scroll of Comparative Example 1 is larger in all measurement regions R1 to R4 than the movable scroll of Example and Comparative Example 2. The greater the amount of change in the bottom surface position, the greater the degree of deformation of the movable scroll. That is, it was confirmed that the movable scroll 26 of the embodiment is suppressed from being deformed during the operation of the scroll compressor 101 by the shot peening process of the second main surface 26e.

(5) Modifications Modifications applicable to the embodiment of the present invention will be described.

  In the movable scroll 26 of the embodiment, as shown in FIG. 5, the entire second main surface 26 e is shot peened. However, only a part of the second main surface 26e may be shot peened. FIG. 10 is a bottom view of the movable scroll 26 of this modification. In FIG. 10, the region of the second main surface 26e that has been shot peened is shown as a hatched region. In this modification, shot peening is performed only on a part of the second main surface 26e and on the outer peripheral side of the upper end bearing 26c. Even when only a part of the second main surface 26e is shot peened, a compressive residual stress can be applied to the second end plate 26a of the movable scroll 26. Therefore, the deformation of the movable scroll 26 during operation of the scroll compressor 101 is suppressed by subjecting only a part of the second main surface 26e to the shot peening process.

  The scroll compressor according to the present invention can remove the tensile residual stress acting on the movable scroll in a short time and at low cost, and can suppress the deformation of the movable scroll during operation.

DESCRIPTION OF SYMBOLS 10 Casing 17 Crankshaft 24 Fixed scroll 26 Movable scroll 26a 2nd end plate (movable end plate)
26b Second lap (movable wrap)
26c Top end bearing (cylindrical part)
26d 1st main surface 26e 2nd main surface 101 Scroll compressor

Japanese Patent Laid-Open No. 62-164819 JP 54-133420 A JP 2012-115925 A

Claims (5)

A casing (10);
A fixed scroll (24) housed in the casing;
A movable scroll (26) housed in the casing, formed of spheroidal graphite cast iron, and meshed with the fixed scroll to compress the refrigerant;
A crankshaft (17) housed in the casing and driving the movable scroll;
With
The movable scroll is
A disc-shaped movable end plate (26a) having a first main surface (26d) and a second main surface (26e);
A spiral movable wrap (26b) extending from the first main surface;
A cylindrical portion (26c) extending from the second main surface and into which the crankshaft is fitted,
At least a part of the second main surface is shot peened so that compressive residual stress acts on the movable end plate,
The compressive residual stress is a stress acting toward the center of the second main surface along the radial direction of the second main surface.
Scroll compressor (101). The compressive residual stress is a stress having a negative average residual stress value,
The average residual stress values are located at equal intervals along the circumferential direction of the second main surface with respect to the radial intermediate point between the outer edge of the cylindrical portion and the outer edge of the second main surface. An average of residual stress values acting at each of the plurality of said intermediate points,
The residual stress value is negative when stress toward the center from the outer edge of the second main surface in the radial direction acts on the movable mirror plate, and the outer edge from the center of the second main surface in the radial direction. Is positive when the stress toward
The scroll compressor according to claim 1. The entire second main surface is shot peened,
The scroll compressor according to claim 1 or 2. The ratio between the thickness (T1) of the movable wrap and the thickness (T2) of the movable mirror plate is 10 or less.
The scroll compressor according to any one of claims 1 to 3. The spheroidal graphite cast iron is FCD600.
The scroll compressor according to any one of claims 1 to 4.

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