JP2007263105A - Compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a miniaturizable compressor inexpensively providable on the market, without losing conventional slidability and processability. <P>SOLUTION: This compressor 1 has a first constituting part 23 and a first sliding part 24. The first constituting part can be welded by a laser. The first sliding part is composed of cast iron having a carbon quantity of 2.0 wt.% to 2.7 wt.% and weldable by the laser. The first sliding part is joined to the first constituting part by laser welding without using a dissoluble material. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a compressor, and more particularly to a compressor that achieves miniaturization (diameter reduction).

In the past, a technique has been proposed in which a pure nickel thin film is sandwiched between cast iron and a steel material, and laser light is irradiated from the steel material side to weld the cast iron and the steel material (see, for example, Patent Document 1).
JP 2001-334378 A

  By the way, in recent years, particularly in Japanese society, it is difficult to secure an installation space and the like, and therefore, downsizing of air conditioners, water heaters, and the like is desired. In order to achieve this downsizing, it is impossible to avoid downsizing compressors belonging to a large class of component parts.

  Therefore, for example, it is conceivable to switch the method of joining component parts from “bolt fastening” that has been conventionally performed to “laser welding”. If the joining method is switched from “bolt fastening” to “laser welding” in this way, the part provided exclusively for bolt joining can be eliminated, and the compressor can be downsized (smaller diameter). That is why. In addition, since there is no need for the material used for the portion provided for the bolt connection, the merit that the material cost can be reduced can be enjoyed. However, when the conventional technique as described above is adopted as laser welding, nickel itself is expensive, and thus there is a possibility that the above-described effect of reducing the material cost cannot be fully enjoyed.

  Moreover, when welding carbon steel, the carbon steel whose carbon amount is 0.3 wt% or less is normally selected. However, since there are many sliding parts in the compressor, there is a situation that a material having a high carbon content is preferred in order to ensure slidability. Moreover, since the raw material becomes poor in workability when the carbon content becomes low, it is preferable that the carbon content is as large as possible.

  The subject of this invention is providing the compressor which can be reduced in size, can be provided to a market cheaply, and does not lose the conventional slidability and workability.

  A compressor according to a first aspect of the present invention includes a first component part and a first sliding part. The first component can be laser welded. The first sliding component is made of cast iron having a carbon content of 2.0 wt% or more and 2.7 wt% or less and capable of laser welding. Here, “cast iron having a carbon content of 2.0 wt% or more and 2.7 wt% or less and capable of laser welding” is manufactured by, for example, a semi-molten die casting method or a semi-solid die casting method. Cast iron or the like constituting the molded product. And this 1st sliding component is joined with the 1st component by laser welding, without using a filler material. The component part may be a sliding part different from the first sliding part or a non-sliding part. Further, the “sliding part” mentioned here is, for example, a fixed scroll or a housing (bearing portion).

  In this compressor, the first sliding component made of cast iron having a carbon amount of 2.0 wt% or more and 2.7 wt% or less and capable of laser welding is joined to the first component by laser welding. For this reason, in this compressor, bolting is not required, miniaturization (small diameter) is possible, and the conventional slidability and workability are not lost. Further, the portion provided for the bolt joining can be eliminated, and further, since a filler material such as a nickel material is not used in laser welding, the raw material cost can be sufficiently reduced. Therefore, this compressor can be miniaturized, can be provided at low cost to the market, and does not lose the conventional slidability and workability.

  The compressor according to the second invention is the compressor according to the first invention, and the cast iron is heat-treated so that the tensile strength is 600 MPa or more and 900 MPa or less after being quenched and chilled as a whole. It is cast iron in which a fine metal structure is formed. That is, the first sliding component corresponds to a part that has been heat-treated after being molded by a semi-molten die-cast molding method or a semi-solid die-cast molding method. Here, the term “fine” means that it is finer than the metal structure of flake graphite cast iron.

  In this compressor, cast iron is cast iron in which a fine metal structure is formed as a result of being heat-treated so that the tensile strength becomes 600 MPa or more and 900 MPa or less after being quenched and chilled as a whole. For this reason, this compressor exhibits high durability and is excellent in toughness as compared with FC material, so that it is difficult to cause damage due to sudden increase in internal pressure or foreign object biting, and even if it is damaged, it is fine. It is possible to enjoy the merit that it is difficult to generate dust and the piping need not be cleaned.

  The compressor according to the third invention is the compressor according to the first invention or the second invention, and in laser welding, the heat input per unit length in the welding direction is 10 (J / mm) or more and 70 (J / Mm), the laser beam is adjusted to be less than or equal to. If the heat input is less than 10 (J / mm), the penetration depth becomes shallow and sufficient fastening cannot be performed, and if it exceeds 70 (J / mm), the tensile strength of cast iron is about 30 to 40%. There is a problem that the fatigue strength also decreases as it decreases.

  At the time of manufacturing the compressor, the laser beam is adjusted so that the heat input per unit length in the welding progress direction is 10 (J / mm) or more and 70 (J / mm) or less in laser welding. According to the experiment results of the present inventor, if the heat input is 70 (J / mm) or less, the tensile strength of cast iron in the laser welded portion can be maintained at 80% or more, and in the plane bending test, the tensile strength is 0. It has become clear that a 4-0.5 (fatigue limit / cast iron strength) can be obtained. For this reason, this compressor can maintain the tensile strength of the laser welded part at 80% or more, and can obtain (fatigue limit / cast iron strength) of 0.4 to 0.5 in the plane bending test. .

  A compressor according to a fourth invention is the compressor according to the third invention, and the laser beam is a fiber laser beam.

  In this compressor, fiber laser light is used for laser welding. For this reason, in this compressor, since deep penetration is obtained at the time of laser welding, low heat input joining becomes possible.

  A compressor according to a fifth aspect is the compressor according to the third aspect or the fourth aspect, wherein the laser beam has a spot diameter of φ0.2 mm or more and φ0.7 mm or less. If the spot diameter is less than φ0.2 mm, poor penetration due to misalignment of the welding position tends to occur, and if it is larger than φ0.7 mm, the necessary penetration depth cannot be obtained. In order to obtain the necessary penetration depth, it is necessary to slow down the processing speed. However, if the processing speed is slowed down, the heat-affected part becomes large, and the tensile strength of that part is lowered.

  In this compressor, laser light having a spot diameter of φ0.2 mm or more and φ0.7 mm or less is used in laser welding. For this reason, in this compressor, it is possible to prevent a penetration failure due to a welding position shift.

  A compressor according to a sixth aspect of the invention is the compressor according to any one of the first to fifth aspects of the invention, wherein the first component has a first fastening surface. The first fastening surface has a center line surface roughness (Ra) of 1.2 μm or less and a flatness of 0.03 mm or less. The first sliding component has a second fastening surface. The second fastening surface has a center line surface roughness (Ra) of 1.2 μm or less and a flatness of 0.03 mm or less. In laser welding, the second fastening surface and the first fastening surface are laser welded.

  When laser welding is performed, the laser beam is irradiated with the second fastening surface and the first fastening surface pressed against each other. If the processing accuracy of the fastening surface is low, the laser beam is irradiated between the first fastening surface and the second fastening surface. As a result, gaps are likely to occur in the welds, and welding defects are likely to occur. When the fastening surface is pressed with a large force to reduce the gaps, the first sliding component and the first component are distorted, and the performance and reliability of the compressor Leading to a decline. However, in this compressor, the centerline surface roughness (Ra) of the first fastening surface and the second fastening surface is 1.2 μm or less, and the flatness is 0.03 mm or less. For this reason, in this compressor, it can prevent that a clearance gap produces between a 1st fastening surface and a 2nd fastening surface. Therefore, in this compressor, it is not necessary to press the fastening surface with a large force. In other words, this compressor can prevent welding defects while maintaining performance and reliability.

  A compressor according to a seventh aspect is the compressor according to the sixth aspect, wherein the first component has a first plate part and a first surrounding wall part. The first enclosure wall portion is erected from the first plate portion. And a 1st fastening surface is an end surface on the opposite side to the 1st board part side of a 1st enclosure wall part. The first sliding component has a second plate portion and a second surrounding wall portion. The second enclosure wall portion is erected from the second plate portion. And a 2nd fastening surface is an end surface on the opposite side to the 2nd board part side of a 2nd enclosure wall part.

  In this compressor, the first fastening surface is an end surface on the opposite side of the first enclosure wall portion on the first plate portion side, and the second fastening surface is an end surface on the opposite side of the second enclosure wall portion on the second plate portion side. It is. For this reason, this compressor can be downsized (reduced in diameter) while eliminating the need to consider the tightening torque of the bolts, forgetting to install the bolts, mixing in the bolts, and the like.

  A compressor according to an eighth invention is the compressor according to the sixth invention or the seventh invention, and in laser welding, a contact portion between the first fastening surface and the second fastening surface is welded over the entire circumference. The

  In this compressor, the contact portion between the first fastening surface and the second fastening surface is welded over the entire circumference in laser welding. For this reason, in this compressor, reliable sealing is possible compared with bolt fastening, and an improvement in performance can be expected.

  A compressor according to a ninth invention is the compressor according to any one of the first to eighth inventions, and compresses carbon dioxide.

  When compressing a high-pressure refrigerant such as carbon dioxide in a compressor in which the first component and the first sliding part are bolted in a normal manner, the fastening strength is not sufficient. Or, if the compressor is a scroll compressor, non-uniform distortion of the scroll spiral may occur. However, in the compressor according to the present invention, the first component part and the first sliding part are firmly fastened by laser welding. For this reason, in this compressor, even if it is a case where carbon dioxide is employ | adopted as a refrigerant | coolant, such a problem does not arise. The first component and the first sliding component are preferably laser welded over the entire circumference.

  The compressor according to the first invention can be miniaturized, can be provided at low cost to the market, and does not lose the conventional slidability and workability.

  The compressor according to the second invention exhibits high durability and is excellent in toughness as compared with the FC material, so that it is difficult to cause damage due to sudden increase in internal pressure or foreign object biting, and even if it is damaged temporarily It is possible to enjoy the merit that it is difficult to make fine dust and the piping need not be cleaned.

  The compressor according to the third aspect of the invention can maintain the tensile tensile strength of the laser welded portion at 80% or more, and obtain (fatigue limit / cast iron strength) of 0.4 to 0.5 in the plane bending test. Can do.

  In the compressor according to the fourth invention, since deep penetration is obtained during laser welding, low heat input joining is possible.

  In the compressor which concerns on 5th invention, the penetration defect by the shift | offset | difference of a welding position can be prevented.

  In the compressor according to the sixth aspect of the invention, it is possible to prevent a gap from being generated between the first fastening surface and the second fastening surface. Therefore, in this compressor, it is not necessary to press the fastening surface with a large force. In other words, this compressor can prevent welding defects while maintaining performance and reliability.

  The compressor according to the seventh aspect of the present invention eliminates the need for considering the tightening torque of the bolts, forgetting to install the bolts, mixing in the bolts, and the like, and can reduce the size (reduction in diameter).

  In the compressor according to the eighth aspect of the invention, reliable sealing is possible compared to bolt fastening, and an improvement in performance can be expected.

  In the compressor according to the ninth aspect, since the first component and the first sliding component are firmly fastened by laser welding, the refrigerant from the fastening portion is used even when carbon dioxide is employed as the refrigerant. Such as leakage or non-uniform distortion of the scroll spiral.

  The high and low pressure dome type compressor 1 according to the embodiment of the present invention constitutes a refrigerant circuit together with an evaporator, a condenser, an expansion mechanism, and the like, and plays a role of compressing a gas refrigerant in the refrigerant circuit. As shown in FIG. 1, the sealed dome-shaped casing 10 having a vertically long cylindrical shape, the scroll compression mechanism 15, the Oldham ring 39, the drive motor 16, the lower main bearing 60, the suction pipe 19, and the discharge pipe 20. It is composed of Hereinafter, the components of the high-low pressure dome compressor 1 will be described in detail.

[Details of components of the high and low pressure dome compressor]
(1) Casing The casing 10 includes a substantially cylindrical trunk casing portion 11, a bowl-shaped upper wall portion 12 that is airtightly welded to the upper end portion of the trunk casing portion 11, and a lower end of the trunk casing portion 11. And a bowl-shaped bottom wall portion 13 which is welded to the portion in an airtight manner. The casing 10 mainly accommodates a scroll compression mechanism 15 that compresses a gas refrigerant and a drive motor 16 that is disposed below the scroll compression mechanism 15. The scroll compression mechanism 15 and the drive motor 16 are connected by a drive shaft 17 disposed so as to extend in the vertical direction in the casing 10. As a result, a gap space 18 is generated between the scroll compression mechanism 15 and the drive motor 16.

(2) Scroll Compression Mechanism As shown in FIG. 1, the scroll compression mechanism 15 mainly includes a housing 23, a fixed scroll 24 disposed in close contact with the housing 23, and a movable meshing with the fixed scroll 24. And a scroll 26. Hereinafter, the components of the scroll compression mechanism 15 will be described in detail.

a) Housing The housing 23 mainly includes a plate portion 23a and a first outer peripheral wall 23b erected from the outer peripheral surface of the plate portion. The housing 23 is press-fitted and fixed to the body casing portion 11 over the entire outer circumferential surface in the circumferential direction. That is, the body casing part 11 and the housing 23 are in close contact with each other in an airtight manner over the entire circumference. For this reason, the inside of the casing 10 is partitioned into a high pressure space 28 below the housing 23 and a low pressure space 29 above the housing 23. The housing 23 is formed with a housing recess 31 that is recessed at the center of the upper surface, and a bearing portion 32 that extends downward from the center of the lower surface. A bearing hole 33 penetrating in the vertical direction is formed in the bearing portion 32, and the drive shaft 17 is rotatably fitted in the bearing hole 33 via a bearing 34.

b) Fixed Scroll The fixed scroll 24 mainly includes an end plate 24a, a spiral (involute) wrap 24b formed on the lower surface of the end plate 24a, and a second outer peripheral wall 24c surrounding the wrap 24b. . A discharge passage 41 that communicates with the compression chamber 40 (described later) and an enlarged recess 42 that communicates with the discharge passage 41 are formed in the end plate 24a. The discharge passage 41 is formed so as to extend in the vertical direction at the central portion of the end plate 24a. The enlarged concave portion 42 is constituted by a concave portion that is recessed in the upper surface of the end plate 24a and extends in the horizontal direction. A lid 44 is fastened and fixed to the upper surface of the fixed scroll 24 by bolts 44 a so as to close the enlarged concave portion 42. And the muffler space 45 which consists of an expansion chamber which silences the driving | running | working sound of the scroll compression mechanism 15 by covering the expansion recessed part 42 with the cover body 44 is formed. The fixed scroll 24 and the lid 44 are sealed by being brought into close contact via a packing (not shown).

c) Movable Scroll The movable scroll 26 mainly includes an end plate 26a, a spiral (involute) wrap 26b formed on the upper surface of the end plate 26a, a bearing portion 26c formed on the lower surface of the end plate 26a, and the end plate 26a. It is comprised from the groove part 26d formed in the both ends. The movable scroll 26 is supported by the housing 23 by fitting an Oldham ring 39 into the groove. Further, the upper end of the drive shaft 17 is fitted into the bearing portion 26c. The movable scroll 26 revolves in the housing 23 without being rotated by the rotation of the drive shaft 17 by being incorporated in the scroll compression mechanism 15 in this way. The wrap 26b of the movable scroll 26 is meshed with the wrap 24b of the fixed scroll 24, and a compression chamber 40 is formed between the contact portions of both the wraps 24b and 26b. In the compression chamber 40, the volume between the laps 24b and 26b contracts toward the center as the movable scroll 26 revolves. In the high-low pressure dome type compressor 1 according to the present embodiment, the gas refrigerant is compressed in this way.

d) Others In the scroll compression mechanism 15, a communication passage 46 is formed across the fixed scroll 24 and the housing 23. The communication passage 46 is formed so that a scroll-side passage 47 formed in the fixed scroll 24 and a housing-side passage 48 formed in the housing 23 communicate with each other. The upper end of the communication passage 46, that is, the upper end of the scroll side passage 47 opens into the enlarged recess 42, and the lower end of the communication passage 46, that is, the lower end of the housing side passage 48 opens into the lower end surface of the housing 23. In other words, the lower end opening of the housing side passage 48 constitutes a discharge port 49 through which the refrigerant in the communication passage 46 flows out into the gap space 18.

(3) Oldham ring The Oldham ring 39 is a member for preventing the rotation of the movable scroll as described above, and is fitted into an Oldham groove (not shown) formed in the housing 23. The Oldham groove is an oval groove and is disposed at a position facing each other in the housing 23.

(4) Drive Motor The drive motor 16 is a DC motor in the present embodiment, and mainly includes an annular stator 51 fixed to the inner wall surface of the casing 10 and a slight gap (air gap) inside the stator 51. The rotor 52 is rotatably accommodated with a passage). The drive motor 16 is arranged such that the upper end of the coil end 53 formed on the upper side of the stator 51 is at substantially the same height as the lower end of the bearing portion 32 of the housing 23.

  In the stator 51, a copper wire is wound around a tooth portion, and a coil end 53 is formed above and below. Further, the outer peripheral surface of the stator 51 is provided with core cut portions that are notched at a plurality of locations from the upper end surface to the lower end surface of the stator 51 and at predetermined intervals in the circumferential direction. The core cut portion forms a motor cooling passage 55 extending in the vertical direction between the body casing portion 11 and the stator 51.

  The rotor 52 is drivably coupled to the movable scroll 26 of the scroll compression mechanism 15 via a drive shaft 17 disposed at the axial center of the trunk casing 11 so as to extend in the vertical direction. A guide plate 58 for guiding the refrigerant that has flowed out of the discharge port 49 of the communication passage 46 to the motor cooling passage 55 is disposed in the gap space 18.

(5) Lower Main Bearing The lower main bearing 60 is disposed in the lower space below the drive motor 16. The lower main bearing 60 is fixed to the body casing portion 11 and constitutes a lower end side bearing of the drive shaft 17 to support the drive shaft 17.

(6) Suction Pipe The suction pipe 19 is for guiding the refrigerant in the refrigerant circuit to the scroll compression mechanism 15 and is fitted into the upper wall portion 12 of the casing 10 in an airtight manner. The suction pipe 19 penetrates the low pressure space 29 in the vertical direction, and an inner end portion is fitted into the fixed scroll 24.

(7) Discharge pipe The discharge pipe 20 is for discharging the refrigerant in the casing 10 to the outside of the casing 10, and is fitted into the body casing portion 11 of the casing 10 in an airtight manner. The discharge pipe 20 has an inner end 36 that is formed in a cylindrical shape extending in the vertical direction and is fixed to the lower end of the housing 23. The inner end opening of the discharge pipe 20, that is, the inflow port, is opened downward.

[Method of manufacturing housing and fixed scroll]
In the present embodiment, the housing 23 and the fixed scroll 24 are manufactured by the following manufacturing method.

(1) Raw material In this Embodiment, as an iron raw material used as the raw material of the said component, C: 2.3-2.4 wt%, Si: 1.95-2.05 wt%, Mn: 0.6-0 7 wt%, P: <0.035 wt%, S: <0.04 wt%, Cr: 0.00-0.50 wt%, Ni: 0.50-1.00 wt% are added. The In addition, the weight ratio here is a ratio with respect to the whole quantity. Here, the “billet” means a material before final molding which is formed into a cylindrical shape or the like by a continuous casting apparatus after the iron material having the above components is melted in a melting furnace. Here, the content of C and Si is such that the tensile strength and tensile elastic modulus are higher than those of flake graphite cast iron, and the component base of a complicated shape (the one before becoming the final component) It is determined so as to satisfy both of having appropriate fluidity for molding. The content of Ni is determined so as to constitute a metal composition suitable for improving the toughness of the metal structure and preventing surface cracks during molding.

(2) Manufacturing process The said component is manufactured through a semi-molten die-casting process, a heat treatment process, and a final finishing process. Hereinafter, each process is explained in full detail.

a) Semi-molten die-cast molding process In the semi-molten die-cast molding process, first, the billet is heated to a high frequency to be in a semi-molten state. Next, when the billet in the semi-molten state is poured into a predetermined mold, the billet is formed into a desired shape while applying a predetermined pressure with a die casting machine, thereby obtaining a component base. Then, when the component base is taken out of the mold and rapidly cooled, the metal structure of the component base is entirely whitened. Note that the component base is slightly larger than the finally obtained component, and this component base becomes the final component after the machining allowance is removed in the final finishing step.

b) Heat treatment step In the heat treatment step, the component base body after the semi-molten die cast molding step is heat treated. In this heat treatment step, the metal structure of the component base changes from a whitened structure to a metal structure composed of pearlite / ferrite matrix and granular graphite. The graphitization and pearlization of the whitened structure can be adjusted by adjusting the heat treatment temperature, holding time, cooling rate, and the like. For example, as described in Honda R & D Technical Review Vol.14 No.1 paper "Study on the semi-melting technology of iron", cooling at 0.05 to 0.10 ° C / sec after holding at 950 ° C for 60 minutes By slowly cooling in the furnace at a speed, tensile strength of about 500 MPa to 700 MPa, HB150 (HRB81 (converted value from SAE J417 hardness conversion table)) to HB200 (HRB96 (SAE J417 hardness conversion table) A metal structure having a hardness of the order of conversion))) can be obtained. Such a metal structure is soft and excellent in machinability because it has a ferrite center, but there is a possibility of forming a cutting edge during machining and reducing the tool life. In addition, after holding at 1000 ° C. for 60 minutes, air cooling, and further holding for a predetermined time at a temperature slightly lower than the initial temperature and then air cooling, tensile strength of about 600 MPa to 900 MPa, HB200 (HRB96 (SAE J 417 hardness conversion) Conversion value from the table)) to HB250 (HRB105, HRC26 (conversion value from SAE J417 hardness conversion table, HRB105 is a reference value because it exceeds the effective practical range of the test type))) A metal structure can be obtained. In such a metal structure, those having hardness equivalent to flake graphite cast iron have machinability equivalent to flake graphite cast iron, and machinability compared to spheroidal graphite cast iron having equivalent ductility and toughness. Is excellent. In addition, by holding the oil at 1000 ° C. for 60 minutes, cooling with oil, and holding the air at a temperature slightly lower than the initial temperature for a predetermined time and then air cooling, tensile strength of about 800 MPa to 1300 MPa, HB250 (HRB105, HRC26 (SAE J 417) Conversion value from hardness conversion table, HRB105 is a reference value because it exceeds the effective practical range of test type))-HB350 (HRB122, HRC41 (converted value from SAE J417 hardness conversion table, HRB122) It is possible to obtain a metal structure having a hardness of a reference level because it exceeds the effective practical range of the test type. Such a metal structure is hard because it has a pearlite center and is inferior in machinability, but has excellent wear resistance. However, there is a possibility of having aggressiveness to the sliding counterpart material due to being too hard.

  In this embodiment, in this heat treatment step, the hardness of the sliding component base is higher than HRB90 (HB176 (converted value from SAE J417 hardness conversion table)) and HRB100 (HB219 (SAE J417 hardness converted). Heat treatment is performed under such a condition that it is lower than the conversion value from the table)). In addition, when the sliding component base is manufactured by a semi-molten die casting method, it is clear that the hardness of the sliding component base is proportional to the tensile strength of the sliding component base. Further, the tensile strength of the sliding component base at this time substantially corresponds to the range of 600 MPa to 900 MPa.

c) Final finishing step In the final finishing step, the component base is machined to complete the component. In the present embodiment, the standard value of the center line surface roughness (Ra) of the lower end surface Ps2 (see FIG. 2) of the fixed scroll 24 is 0.6 to 1.2 μm, and the standard value of flatness Is set to 0.01 to 0.03 mm. The standard value of the center line surface roughness (Ra) of the upper end surface Ps1 (see FIG. 2) of the housing 23 is 0.6 to 1.2 μm, and the standard value of flatness is 0.01 to 0.00. 03 mm.

[Method of joining housing and fixed scroll]
In the present embodiment, the housing 23 and the fixed scroll 24 are fastened not by bolting but by laser welding. Specifically, after incorporating the crankshaft 17, the movable scroll 26, the Oldham ring 39, etc. into the housing 23, the upper end surface Ps1 of the housing 23 and the lower end surface Ps2 of the fixed scroll 24 are abutted and pressed from both sides, A fiber laser beam LS with a spot diameter of 0.3 mm is irradiated so as to sandwich the contact surface. At this time, the output / welding speed of the fiber laser beam LS is adjusted so that the heat input per unit length in the welding direction is 50 ± 5 (J / mm). Moreover, in this Embodiment, the contact surface is laser-welded over the perimeter. In the present embodiment, laser welding is performed from the outer periphery to the inner periphery.

[Operation of high and low pressure dome type compressor]
When the drive motor 16 is driven, the drive shaft 17 rotates, and the revolving operation is performed without rotating the movable scroll. Then, the low-pressure gas refrigerant is sucked into the compression chamber 40 from the peripheral side of the compression chamber 40 through the suction pipe 19 and is compressed as the volume of the compression chamber 40 changes, and becomes a high-pressure gas refrigerant. The high-pressure gas refrigerant is discharged from the central portion of the compression chamber 40 through the discharge passage 41 to the muffler space 45, and then passes through the communication passage 46, the scroll side passage 47, the housing side passage 48, and the discharge port 49. Then, it flows out into the gap space 18 and flows downward between the guide plate 58 and the inner surface of the body casing portion 11. When the gas refrigerant flows downward between the guide plate 58 and the inner surface of the body casing portion 11, a part of the gas refrigerant is diverted to form a circle between the guide plate 58 and the drive motor 16. Flow in the direction. At this time, the lubricating oil mixed in the gas refrigerant is separated. On the other hand, the other part of the diverted gas refrigerant flows downward in the motor cooling passage 55, flows to the lower motor space, and then reverses to become an air gap passage between the stator 51 and the rotor 52, or to communicate therewith. It flows upward through the motor cooling passage 55 on the side facing the passage 46 (left side in FIG. 1). Thereafter, the gas refrigerant that has passed through the guide plate 58 and the gas refrigerant that has flowed through the air gap passage or the motor cooling passage 55 merge in the gap space 18 and flow into the discharge pipe 20 from the inner end 36 of the discharge pipe 20. And discharged outside the casing 10. The gas refrigerant discharged to the outside of the casing 10 circulates through the refrigerant circuit, and is again sucked into the scroll compression mechanism 15 through the suction pipe 19 and compressed.

[Characteristics of high / low pressure dome type compressor]
(1)
In the high and low pressure dome type compressor 1 according to the embodiment of the present invention, the fixed scroll 24 manufactured by a semi-molten die casting method and containing carbon amount of 2.3 to 2.4 wt% is not bolted but laser welded. And is fastened to the housing 23. For this reason, in this high-low pressure dome type compressor 1, it becomes possible to reduce the size (smaller diameter) and not lose the conventional slidability and workability.

(2)
In the high and low pressure dome type compressor 1 according to the embodiment of the present invention, the fixed scroll 24 is formed by a semi-molten die casting method, and the tensile strength is adjusted to 600 MPa or more and 900 MPa or less by heat treatment. For this reason, the high and low pressure dome type compressor 1 exhibits high durability and is excellent in toughness as compared with the FC material, so that it is difficult to cause damage due to sudden increase in internal pressure or foreign object biting, and it is temporarily damaged. Even if it is difficult to produce fine dust, it is not necessary to clean the piping.

(3)
In the high-low pressure dome type compressor 1 according to the embodiment of the present invention, when laser welding the housing 23 and the fixed scroll 24, the heat input per unit length in the welding progress direction is 50 ± 5 (J / mm). The output and welding speed of the fiber laser light LS are adjusted so that For this reason, in this high and low pressure dome type compressor 1, the tensile strength of the laser welded portion W can be maintained at 80% or more, and 0.4 to 0.5 (fatigue limit / cast iron strength in the plane bending test). ) Can be obtained.

(4)
In the high and low pressure dome compressor 1 according to the embodiment of the present invention, fiber laser light LS is used when laser welding the housing 23 and the fixed scroll 24. For this reason, in this high and low pressure dome type compressor 1, since deep penetration is obtained at the time of laser welding, low heat input joining becomes possible.

(5)
In the high / low pressure dome type compressor 1 according to the embodiment of the present invention, fiber laser light LS having a spot diameter of φ0.3 mm is used in laser welding. For this reason, in this high / low pressure dome type compressor 1, it is possible to prevent poor penetration due to misalignment of the welding position.

(6)
In the high / low pressure dome type compressor 1 according to the present embodiment, the standard values of the center line surface roughness (Ra) of the lower end surface Ps2 of the fixed scroll 24 and the upper end surface Ps1 of the housing 23 are 0.6 to 1.. The standard value of flatness is 0.01 to 0.03 mm. For this reason, in this high-low pressure dome type compressor 1, welding defects can be prevented while maintaining performance and reliability.

(7)
In the high and low pressure dome type compressor 1 according to this embodiment, the contact surface is laser welded over the entire circumference. For this reason, in this high and low pressure dome type compressor 1, a reliable seal can be achieved as compared with bolt fastening, and an improvement in performance can be expected. Therefore, the high-low pressure dome type compressor 1 can compress a high-pressure refrigerant such as carbon dioxide.

[Modification]
(A)
In the previous embodiment, the hermetic type high / low pressure dome type compressor 1 is adopted. However, the compressor may be a high pressure dome type compressor or a low pressure dome type compressor. Moreover, a semi-hermetic type or an open type compressor may be used.

(B)
In the high and low pressure dome type compressor 1 according to the previous embodiment, the Oldham ring 39 is employed as the rotation prevention mechanism. However, a pin, a ball coupling, a crank, or the like may be employed as the rotation prevention mechanism.

(C)
In the previous embodiment, the case where the compressor 1 is used in the refrigerant circuit has been described as an example. However, the application is not limited to air conditioning, and a compressor or a single unit incorporated in a system or A blower, a supercharger, a pump, etc. may be sufficient.

(D)
In the high and low pressure dome type compressor 1 according to the previous embodiment, lubricating oil was present, but an oilless or oil-free (oil may or may not be) type compressor, blower, supercharger, It may be a pump.

(E)
In the high and low pressure dome type compressor 1 according to the previous embodiment, the housing 23 and the fixed scroll 24 are formed by a semi-molten die casting method, and contain a carbon amount of 2.3 to 2.4 wt%. However, the carbon content should just be 2.0 wt% or more and 2.7 wt% or less.

(F)
In the high and low pressure dome type compressor 1 according to the previous embodiment, the housing 23 and the fixed scroll 24 are formed by a semi-molten die casting method. However, the housing 23 and the fixed scroll 24 are formed by a semi-solid die casting method. May be formed.

(G)
In the laser welding according to the previous embodiment, the fiber laser beam LS having a spot diameter of φ0.3 mm is used, but the spot diameter may be from φ0.2 mm to φ0.7 mm.

(H)
In the laser welding according to the previous embodiment, fiber laser light is used, but other types of laser light may be used.

(I)
In the high / low pressure dome compressor 1 according to the previous embodiment, the standard value of the center line surface roughness (Ra) of the lower end surface Ps2 of the fixed scroll 24 and the upper end surface Ps1 of the housing 23 before laser welding is 0.6. However, the standard value of the center line surface roughness (Ra) may be 1.2 μm or less.

(J)
In the high / low pressure dome compressor 1 according to the previous embodiment, the standard value of the flatness of the lower end surface Ps2 of the fixed scroll 24 and the upper end surface Ps1 of the housing 23 before laser welding is set to 0.01 to 0.03 mm. However, the standard value of flatness should just be 0.03 mm or less.

(K)
In the previous embodiment, in the high and low pressure dome type compressor 1, the housing 23 and the fixed scroll 24 were molded by a semi-molten die casting method using a burette having a carbon content of 2.3 to 2.4 wt%. In swing compressors and rotary compressors, cylinders, front heads, rear heads, middle plates, etc. are similarly molded by a semi-molten die-cast molding method using a burette with a carbon content of 2.3 to 2.4 wt%. Laser welding may be performed in the same manner as in the above embodiment.

(L)
In the laser welding according to the previous embodiment, the output / welding speed of the fiber laser beam LS was adjusted so that the heat input per unit length in the welding progress direction was 50 ± 5 (J / mm). The amount of heat input may be 10 (J / mm) or more and 70 (J / mm) or less.

  The compressor according to the present invention can be reduced in size, can be provided at low cost to the market, and does not lose the conventional slidability and workability, and has a small installation space. It is useful as a compressor installed in

It is a longitudinal cross-sectional view of the high-low pressure dome type compressor which concerns on embodiment of this invention. It is an enlarged view of the fastening location of the housing and fixed scroll of the high-low pressure dome type compressor which concerns on embodiment of this invention.

Explanation of symbols

1 High and low pressure dome type compressor (compressor)
23 Housing (first component)
23a Plate part (first plate part)
23b 1st outer peripheral wall (1st enclosure wall part)
24 Fixed scroll (first sliding part)
24a End plate (second plate part)
24c 2nd outer peripheral wall (2nd enclosure wall part)
Ps1 Housing top surface (first fastening surface)
Ps2 Fixed scroll bottom end surface (second fastening surface)

Claims (9)

A first component (23) capable of laser welding;
A first slide made of cast iron having a carbon content of 2.0 wt% or more and 2.7 wt% or less and capable of laser welding, and joined to the first component by laser welding without using a filler metal Parts (24);
A compressor (1). The cast iron is a cast iron in which a fine metal structure is formed as a result of heat treatment so that the tensile strength is 600 MPa or more and 900 MPa or less after being quenched and chilled as a whole.
The compressor according to claim 1. In the laser welding, the laser beam (LS) is adjusted so that the heat input per unit length in the welding progress direction is 10 (J / mm) or more and 70 (J / mm) or less.
The compressor according to claim 1 or 2. The laser beam is a fiber laser beam,
The compressor according to claim 3. The laser beam has a spot diameter of φ0.2 mm or more and φ0.7 mm or less,
The compressor according to claim 3 or 4. The first component has a first fastening surface (Ps1) having a center line surface roughness (Ra) of 1.2 μm or less and a flatness of 0.03 mm or less,
The first sliding component has a second fastening surface (Ps2) having a centerline surface roughness (Ra) of 1.2 μm or less and a flatness of 0.03 mm or less,
In the laser welding, the second fastening surface and the first fastening surface are laser welded.
The compressor according to any one of claims 1 to 5. The first component has a first plate portion (23a) and a first surrounding wall portion (23b) erected from the first plate portion,
The first fastening surface is an end surface of the first enclosure wall portion opposite to the first plate portion side,
The first sliding component has a second plate portion (24a) and a second surrounding wall portion (24c) erected from the second plate portion,
The second fastening surface is an end surface on the opposite side of the second surrounding wall portion to the second plate portion side,
The compressor according to claim 6. In the laser welding, the contact portion between the first fastening surface and the second fastening surface is welded over the entire circumference.
The compressor according to claim 6 or 7. Compresses carbon dioxide,
The compressor according to any one of claims 1 to 8.

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