Copper-iron grafted pipe for hermetic compressor

Abstract

The utility model discloses a copper iron grafting pipe of totally enclosed compressor relates to copper pipe connecting technical field, including copper pipe and iron pipe, copper pipe and iron pipe welding form grafting pipe, and iron pipe is close to the iron pipe boss of welding portion, and one side of iron pipe boss is copper pipe and iron pipe connection welding spot, and iron pipe boss is arc boss. Iron pipe adopts copper iron composite pipe, surface copper iron plating pipe or is bondi pipe, and copper pipe adopts phosphorus deoxidized copper, and the utility model discloses a copper pipe one end design is copper pipe, and the other end is iron pipe, has realized the reasonable configuration and the conservation of material, has reduced manufacturing cost effectively.

Description

Technical Field

[0001] This utility model relates to the field of copper pipe connection technology, and in particular to a copper-iron grafting pipe for a fully enclosed compressor. Background Technology

[0002] A typical refrigerator compressor has three external pipe ports, commonly known as the process pipe, suction pipe, and discharge pipe. The basic working principle of a refrigerator compressor is that the motor drives the crankshaft to rotate. The rotation of the crankshaft causes the crankshaft cranks to drive the piston in a reciprocating linear motion within the cylinder via the connecting rod. It draws in low-temperature, low-pressure refrigerant gas through the suction pipe, compresses it with the piston driven by the motor, and then discharges high-temperature, high-pressure refrigerant gas through the discharge pipe, providing power for the refrigeration cycle, thus realizing the refrigeration cycle of compression → condensation → expansion → evaporation and heat absorption. The process pipe on the compressor is used for adding refrigeration oil and refrigerant. After adding, it is sealed using brazing or ultrasonic methods. The process pipe is not connected to the refrigerator system piping. The suction and discharge pipes on the compressor must be connected to the refrigerator system piping to ensure the integrity and sealing of the refrigeration piping.

[0003] Existing compressors use all-copper piping, which is costly and structurally unstable. To address this issue, a copper-iron grafting pipe is designed, partially replacing the copper tubing with iron tubing. This achieves the same performance as copper tubing, enhancing the compressor industry's competitiveness.

[0004] In the prior art, patent publication number CN120819693A discloses a method for manufacturing a corrugated connecting pipe, a pipeline assembly, a four-way valve module, a compressor module, and an air conditioning device, including: a corrugated pipe with a first connector at its end, the outer surface of the first connector including a first hot-pressed surface; a non-metallic braided mesh sleeve fitted over the corrugated pipe, the end of the braided mesh sleeve placed on the first hot-pressed surface; a connecting pipe with a second connector at its end, the second connector being located inside the first connector and sealed to the inner surface of the first connector; and a connecting ring fitted over the end of the braided mesh sleeve and pressed against the first hot-pressed surface. This patent has high production costs and its structure is not stable enough. Utility Model Content

[0005] The purpose of this invention is to solve the problem of high cost of existing grafting pipes. The grafting pipe of this invention has a copper pipe at one end and an iron pipe at the other end, which saves materials and reduces costs.

[0006] Another objective of this invention is to address the issue of the weak stability of existing grafting tube structures. This invention provides a convex bulge on the grafting tube, with a first side recess and a second side recess on both sides, which are welded upwards to the shell. At the same time, the arc-shaped convex bulge structure provides stronger stability.

[0007] To achieve the above objectives, this utility model provides the following technical solution: a copper-iron grafting pipe for a fully enclosed compressor, comprising a copper pipe and an iron pipe, which are welded together to form the grafting pipe. The iron pipe near the weld joint has an iron pipe bulge, and one side of the bulge is the connection weld between the copper pipe and the iron pipe. The bulge is arc-shaped. The iron pipe can be a copper-iron composite pipe, a copper-plated iron pipe, or a Bondi pipe, while the copper pipe is made of phosphorus-deoxidized copper. Considering physical properties, welding strength, economy, and ease of implementation, a copper-plated iron pipe is preferred, followed by a copper-iron composite pipe and a Bondi pipe. While meeting usage requirements, the iron pipe length should be as long as possible to achieve material substitution and cost reduction. The second end face of the copper pipe is inserted into the second end face of the iron pipe, and the insertion depth is determined by three or more iron pipe positioning points extruded from the iron pipe. Then, the two are combined into a novel exhaust grafting pipe through processes such as brazing or high-frequency welding. The iron pipe bulge is welded to the lower housing using welding equipment and electrode fixtures.

[0008] Preferably, the top of the iron pipe protrusion is an upward convex part.

[0009] Preferably, the two sides of the upper convex portion are a first side concave portion and a second side concave portion, respectively.

[0010] Preferably, the angle between the axis of the first side recess and the plane of the iron pipe is 40° to 70°, and the angle between the axis of the second side recess and the plane of the iron pipe is 40° to 60°.

[0011] Preferably, one side of the second concave portion is a connecting portion, which is a concave pit.

[0012] Preferably, one side of the connecting part is the positioning point of the iron pipe.

[0013] Preferably, the copper pipe includes a first end face and a second end face, and the iron pipe includes a first end face and a second end face.

[0014] Preferably, the second end face of the copper pipe abuts against the positioning point of the iron pipe, which is located inside the iron pipe and consists of several small protruding points. These points are used to position the copper pipe during connection before welding the copper and iron pipes.

[0015] Preferably, the first end face of the iron pipe is connected to the cover plate assembly inside the compressor, and the first end face of the copper pipe is connected to the refrigerator system pipe.

[0016] Preferably, the iron pipe protrusion is welded to the lower shell.

[0017] Compared with the prior art, the beneficial effects of this utility model are: by designing one end of the grafting pipe as a copper pipe and the other end as an iron pipe, this utility model achieves reasonable material allocation and conservation, and effectively reduces manufacturing costs.

[0018] This invention features a convex bulge structure on the grafting tube, with a first side recess and a second side recess on each side. This design not only facilitates welding and fixing the grafting tube to the shell, but also further enhances the overall structural stability of the grafting tube due to the arc-shaped convex bulge. Attached Figure Description

[0019] Figure 1 This is a structural diagram of the present utility model.

[0020] Figure 2 for Figure 1 Sectional view at point BB.

[0021] Figure 3 for Figure 2 Enlarged view of point A in the middle.

[0022] Figure 4 for Figure 3 Enlarged view of point C in the middle.

[0023] Figure 5 This is a cross-sectional view of the grafted tube welded shell of this utility model.

[0024] In the diagram: 1. Iron pipe, 2. Copper pipe, 3. Weld joint between copper pipe and iron pipe, 4. Lower shell, 11. First end face of iron pipe, 12. Iron pipe protrusion, 121. Upper protrusion, 122. First side concave part, 123. Second side concave part, 124. Connecting part, 13. Iron pipe positioning point, 14. Second end face of iron pipe, 21. First end face of copper pipe, 22. Second end face of copper pipe. Detailed Implementation

[0025] The technical solution of this utility model will be further described in detail below through specific embodiments and in conjunction with the accompanying drawings. The described embodiments are only some embodiments of this utility model, and not all embodiments.

[0026] Example 1: Refer to Figures 1 to 5A copper-iron grafting pipe for a fully enclosed compressor includes a copper pipe 2 and an iron pipe 1, which are welded together to form an integrated grafting pipe structure. The iron pipe 1 has a protrusion 12 near the welding area, and one side of this protrusion 12 is the connection weld 3 between the copper pipe and the iron pipe. The protrusion 12 is an arc-shaped convex structure. For material selection, the iron pipe 1 can be a copper-iron composite pipe, a copper-plated iron pipe, or a Bondi pipe; the copper pipe 2 is preferably made of phosphorus-deoxidized copper. Considering factors such as physical performance matching, weld joint strength, economic cost, and ease of actual production, a copper-plated iron pipe is the most suitable preferred material for the iron pipe 1, followed by copper-iron composite pipes and Bondi pipes. While meeting the product's performance and reliability requirements, the length ratio of the iron pipe 1 section should be increased as much as possible to achieve a material substitution strategy of replacing copper with iron, thus significantly reducing raw material costs. During assembly, the second end face 22 of the copper tube is inserted into the second end face 14 of the iron tube. Precise positioning of the copper tube insertion depth is achieved using three or more iron tube positioning points 13 pre-extruded on the iron tube 1. Subsequently, brazing or high-frequency welding is used to permanently connect the copper tube 2 and the iron tube 1, forming a novel exhaust grafting pipe. Finally, the iron tube protrusion 12 is welded and fixed to the lower housing 4 of the compressor using specialized welding equipment and matching electrode fixtures.

[0027] In a preferred embodiment, the top of the iron pipe protrusion 12 is configured as an upper protrusion 121. The arcuate profile of the upper protrusion 121 is precisely calculated and designed to ensure optimal contact area and stress distribution when welded to the lower housing 4.

[0028] On both sides of the upper protrusion 121, a first side recess 122 and a second side recess 123 are formed respectively. These two side recesses, together with the upper protrusion 121, constitute the complete waveform structure of the iron pipe bulge 12, which not only helps to guide the flow of heat and stress during the welding process, but also improves the structural flexibility and fatigue resistance of the bulge area.

[0029] The angle between the central axis of the first side recess 122 and the outer wall plane of the main body of the iron pipe 1 is designed to be within the range of 40° to 70°; while the angle between the central axis of the second side recess 123 and the outer wall plane of the main body of the iron pipe 1 is designed to be within the range of 40° to 60°. These specific angle ranges are the result of extensive fluid dynamics simulations and structural strength tests, ensuring minimal flow resistance when the medium flows through this area, while also providing optimal stress distribution for the convex structure under internal pressure, effectively preventing stress concentration.

[0030] In another preferred embodiment, a connecting portion 124 is further provided on one side of the second side recess 123. This connecting portion 124 is specifically a small, inwardly recessed pit structure. This design achieves a smooth transition from the second side recess 123 to the main wall of the iron pipe 1, further optimizing the stress distribution in this area.

[0031] Furthermore, on one side of the connecting portion 124, that is, along the axial direction of the iron pipe 1, the iron pipe positioning point 13 is provided. These positioning points are closely adjacent to the connecting portion 124 in spatial position, forming a complete positioning functional area.

[0032] In one embodiment involving the overall structure, the copper tube 2 includes a first end face 21 and a second end face 22; correspondingly, the iron tube 1 also includes a first end face 11 and a second end face 14. This defined end face provides a clear reference for alignment and connection during the assembly process.

[0033] In a key assembly implementation, after the second end face 22 of the copper tube is inserted into the iron tube 1, its end precisely abuts against the aforementioned iron tube positioning point 13. The iron tube positioning point 13 is a series of outwardly protruding dot-like structures formed on the inner wall of the iron tube 1 through a cold extrusion process. Its main function is to precisely mechanically limit and position the insertion depth of the copper tube 2 when connecting it to the iron tube 1, thereby providing an accurate and consistent alignment basis for subsequent welding operations and ensuring the stability and reliability of the welding quality.

[0034] In the implementation scheme involving interface connections, the first end face 11 of the iron pipe is used to connect with a key component inside the compressor—the cover plate assembly; while the first end face 21 of the copper pipe is used to connect with the system piping of the refrigerator's refrigeration system. This interface allocation fully leverages the respective advantages of the excellent brazing connection of the copper pipe and the good compatibility between the iron pipe and the compressor housing material.

[0035] As previously mentioned, the iron pipe protrusion 12 is permanently fixed to the lower housing 4 of the compressor by welding. This connection point is crucial for reliably securing the exhaust pipe to the main structure of the compressor.

[0036] This invention features a meticulously designed and constructed convex bulge structure 12 with a specific geometric shape on the iron pipe section of the grafting pipe. The convex bulge structure has a first side recess 122 and a second side recess 123 with optimized angles on both sides. This composite curved surface design not only greatly facilitates the welding and fixing operation between the grafting pipe and the compressor housing, improving the stability of the welding process and the quality of the weld joint, but also further enhances the overall structural stability and fatigue resistance of the grafting pipe under complex operating conditions such as vibration and pressure pulsation due to its smooth transition of the arc-shaped convex bulge structure. As an integral reinforcing unit, this convex bulge structure effectively disperses and absorbs the mechanical and thermal stresses generated during pipeline operation, thereby extending the service life of the grafting pipe and improving the reliability of the entire compressor system.

[0037] First, cut iron pipe 1 and copper pipe 2 to the specified lengths according to the design specifications. Iron pipe 1 is preferably made of low-carbon steel with a uniform copper coating of 5-15 μm (i.e., copper-plated iron pipe). The base material can be cold-rolled steel strip of grades ST12 or ST14 to ensure good formability and strength. Copper pipe 2 is made of TU2 phosphorus-deoxidized copper pipe conforming to GB / T 17791-2017 standard. Its excellent plasticity and oxygen-free properties ensure smooth subsequent processing and airtight welding. Before forming, the ends of iron pipe 1 and copper pipe 2 should be deburred and cleaned to remove oil and oxides to ensure welding quality.

[0038] Using a dedicated multi-station cold heading machine or hydraulic forming machine, a protrusion 12 is machined at a predetermined position on the iron pipe 1. The forming process requires precise control of the mold's movement trajectory and pressure to ensure accurate reproduction of the protrusion's geometric dimensions.

[0039] The entire convex hull forming process requires a smooth surface, free from defects such as cracks and wrinkles. After forming, key dimensions of the convex hull, such as height, angle, and transition radius, can be 100% inspected online using an optical measuring instrument.

[0040] At the other end of the iron pipe 1, on the inner side of the second end face 14, a stamping device with a specific punch is used to extrude three or more positioning points 13, typically evenly distributed at 120° intervals, from the inside of the pipe wall outwards. These positioning points are discrete protrusions, not continuous rings, and their height must be strictly controlled, with tolerances typically within ±0.1mm, to ensure the accuracy of the insertion depth of the copper pipe 2. The shape of the positioning points can be hemispherical or frustum-shaped to avoid excessive stress concentration.

[0041] Insert the second end face 22 of the copper tube 2 axially into the second end face 14 of the iron tube 1 until the second end face 22 of the copper tube reliably contacts all the positioning points 13 of the iron tube. At this time, the area to be welded between the copper tube 2 and the iron tube 1, i.e., the area where the connection weld point 3 is located, should have a uniform and appropriately sized gap, usually 0.05-0.15mm, to facilitate the capillary action of the brazing filler metal.

[0042] Subsequently, welding is performed. High-frequency induction brazing is preferred. A paste or ring-shaped brazing filler metal, such as BCu93P, can be applied to the welding area. It has a moderate melting point, good fluidity, and a certain self-fluxing effect. The assembled workpiece is placed into the high-frequency induction coil. By precisely controlling the heating power and time, the brazing filler metal melts and fills the joint gap, while the base material does not melt. After cooling, a dense and strong metallurgical bond is formed. After welding, the weld must be visually inspected and subjected to non-destructive testing such as X-ray or ultrasonic testing to ensure that there are no defects such as porosity, slag inclusions, or incomplete penetration.

[0043] The welded copper-iron grafting pipe assembly is placed in the assembly fixture, aligning the upper protrusion 121 of the iron pipe protrusion 12 with the pre-drilled mounting hole or mounting base on the compressor lower housing 4. Resistance welding, such as projection welding, is then performed. Using a specific electrode fixture, one electrode acts on the inner protrusion area of ​​the iron pipe 1, and the other electrode acts on the corresponding position on the outer side of the lower housing 4. A strong current and pressure are applied, generating resistance heat at the contact interface between the protrusion 12 and the housing 4, causing the local metal to reach a plastic or molten state, forming a weld nugget under pressure. The welding parameters—current, time, and pressure—need to be optimized based on the material thickness and protrusion geometry. After welding, strength testing and airtightness checks are required to ensure a reliable connection.

[0044] Example 2: Refer to Figures 1 to 5 A novel copper-iron composite grafting pipe for a fully enclosed compressor is disclosed. Its structure mainly consists of a copper pipe (2) and an iron pipe (1), which are welded together to form an integrated composite grafting pipe structure. An iron pipe protrusion (12) is located near the welding area on the iron pipe (1), and one side of this protrusion is the connection weld point (3) between the copper and iron pipes. The iron pipe protrusion (12) has an overall arc-shaped convex structure, which enhances the connection strength and optimizes stress distribution.

[0045] Regarding material selection, iron pipe 1 can be made of copper-iron composite pipe, copper-plated iron pipe, or Bundy pipe; copper pipe 2 is preferably made of phosphorus-deoxidized copper. Considering the compatibility of physical properties, weld joint strength, economy, and ease of production, copper-plated iron pipe is the most suitable first choice for iron pipe 1, followed by copper-iron composite pipe and Bundy pipe. While ensuring product performance and reliability, the length proportion of iron pipe 1 in the overall structure should be increased as much as possible to achieve a material substitution strategy of "replacing copper with iron," thereby significantly reducing raw material costs.

[0046] During assembly, the second end face 22 of the copper tube is inserted into the second end face 14 of the iron tube, and the insertion depth of the copper tube is precisely positioned by three or more iron tube positioning points 13 formed in advance by cold extrusion on the iron tube 1. Subsequently, the copper tube 2 and the iron tube 1 are permanently connected by processes such as brazing or high-frequency welding to form a new type of exhaust grafting pipe with stable structure and excellent sealing performance. Finally, using special welding equipment and matching electrode tooling, the iron tube protrusion 12 is welded and fixed to the lower housing 4 of the compressor.

[0047] The top of the iron pipe protrusion 12 is designed as an upper protrusion 121. The arc-shaped profile of the upper protrusion 121 has been precisely calculated and optimized to ensure the best contact area and stress distribution when welding with the lower housing 4, thereby improving the welding quality and connection reliability.

[0048] A first side recess 122 and a second side recess 123 are respectively provided on both sides of the upper convex portion 121. These two side recesses, together with the upper convex portion 121, constitute the complete waveform structure of the iron pipe bulge 12, which not only helps to guide the reasonable distribution of heat and stress during the welding process, but also improves the structural flexibility and fatigue resistance of the bulge area and enhances the overall durability of the grafted pipe.

[0049] The angle between the central axis of the first recess 122 and the outer wall plane of the main body of the iron pipe 1 is designed to be within the range of 40° to 70°; the angle between the central axis of the second recess 123 and the outer wall plane of the main body of the iron pipe 1 is controlled within the range of 40° to 60°. These specific angle ranges are based on the results of extensive fluid dynamics simulations and structural strength tests, which can ensure that the flow resistance is minimized when the medium flows through this area, while also ensuring that the convex structure has optimal stress distribution when subjected to internal pressure, effectively avoiding stress concentration.

[0050] In another preferred embodiment, a connecting portion 124 is provided on one side of the second side recess 123. The connecting portion 124 is a small inwardly recessed pit structure, which realizes a smooth transition from the second side recess 123 to the main pipe wall of the iron pipe 1, further optimizes the stress distribution in this area, and improves the continuity of the structure.

[0051] On one side of the connector 124, iron pipe positioning points 13 are provided along the axial direction of the iron pipe 1. These positioning points are closely adjacent to the connector 124 in spatial position, together forming a complete positioning functional area to ensure precise control of the copper pipe insertion depth.

[0052] In one embodiment involving the overall structure, the copper tube 2 includes a first end face 21 and a second end face 22; correspondingly, the iron tube 1 also includes a first end face 11 and a second end face 14. This clear end face definition provides a clear reference for alignment and connection during the assembly process, which is beneficial for improving assembly accuracy and consistency.

[0053] In the implementation scheme involving interface connections, the first end face 11 of the iron pipe is used to connect with the cover plate assembly inside the compressor; the first end face 21 of the copper pipe is used to connect with the system piping of the refrigerator refrigeration system. This interface allocation fully leverages the advantages of the excellent brazing connection of the copper pipe and the good compatibility between the iron pipe and the compressor housing material, achieving optimal matching of function and performance.

[0054] The protruding iron pipe 12 is permanently fixed to the lower housing 4 of the compressor by welding. This connection point is crucial for reliably fixing the exhaust pipe to the main structure of the compressor, ensuring the stability and safety of the system during operation.

[0055] In summary, the copper-iron grafting pipe of this utility model, through its innovative material combination, ingenious structural design, and optimized manufacturing process, successfully achieves the best balance between performance, cost, and reliability, providing a superior pipeline connection solution for fully enclosed compressors. It not only solves the problem of high cost of traditional all-copper exhaust pipes but also overcomes the shortcomings of poor weldability and corrosion resistance of all-iron exhaust pipes. Furthermore, its unique convex design enhances structural stability and connection reliability. This design is easily integrated into existing production lines, and the manufacturing process is mature and stable, possessing significant economic benefits and market competitiveness. It has broad application prospects in the field of fully enclosed compressors, especially in refrigeration equipment such as household refrigerators and freezers. To more fully demonstrate the implementation details and technical advantages of this utility model, a specific manufacturing and assembly embodiment is described in detail below. However, it should be noted that the scope of protection of this utility model is not limited to the specific parameters and processes described in the following embodiment.

[0056] First, cut iron pipe 1 and copper pipe 2 to the specified lengths according to the design specifications. Iron pipe 1 is preferably made of low-carbon steel with a uniform copper coating of 5-15 μm thickness, i.e., copper-plated iron pipe. The base material can be cold-rolled steel strip of grades ST12 or ST14 to ensure good formability and strength. Copper pipe 2 is made of TU2 phosphorus-deoxidized copper pipe conforming to GB / T 17791-2017 standard. Its excellent plasticity and oxygen-free properties ensure smooth subsequent processing and airtight welding.

[0057] Before forming, the ends of iron pipe 1 and copper pipe 2 should be deburred and cleaned to remove oil and oxides to ensure welding quality.

[0058] Using a dedicated multi-station cold heading machine or hydraulic forming machine, a protrusion 12 is machined at a predetermined position on the iron pipe 1. The forming process requires precise control of the mold's movement trajectory and pressure to ensure accurate reproduction of the protrusion's geometric dimensions.

[0059] Specifically, the convex hull forming process is as follows: Connection part 124: First, a small indentation is pressed into the pipe wall as the initial transition zone.

[0060] Second side recess 123: The mold continues to move, forming a side recessed area with the axis of the mold forming an angle of 40°-60°, preferably 50°, with the tube wall plane.

[0061] Upper convex part 121: When the mold reaches its apex, it forms a smooth arc-shaped convex part, which is the main contact area for welding with the lower shell 4.

[0062] First side recess 122: During mold return, another side recess area is formed with the axis of the mold forming an angle of 40°-70°, preferably 55°, with the tube wall plane.

[0063] The entire convex hull forming process requires a smooth surface, free from defects such as cracks and wrinkles. After forming, key dimensions of the convex hull, such as height, angle, and transition radius, can be 100% inspected online using an optical measuring instrument.

[0064] At the other end of the iron pipe 1, on the inner side of the second end face 14, a stamping device with a specific punch is used to extrude three or more positioning points 13, typically evenly distributed at 120° intervals, from the inside of the pipe wall outwards. These positioning points are discrete protrusions, not continuous rings, and their height must be strictly controlled, with tolerances typically within ±0.1mm, to ensure the accuracy of the insertion depth of the copper pipe 2. The shape of the positioning points can be hemispherical or frustum-shaped to avoid excessive stress concentration.

[0065] Insert the second end face 22 of the copper tube 2 axially into the second end face 14 of the iron tube 1 until the second end face 22 of the copper tube reliably contacts all the positioning points 13 of the iron tube. At this time, the area to be welded between the copper tube 2 and the iron tube 1, i.e., the area where the connection weld point 3 is located, should have a uniform and appropriately sized gap, usually 0.05-0.15mm, to facilitate the capillary action of the brazing filler metal.

[0066] Subsequently, welding is performed. High-frequency induction brazing is preferred. A paste or ring-shaped brazing filler metal, such as BCu93P, can be applied to the welding area. It has a moderate melting point, good fluidity, and a certain self-fluxing effect. The assembled workpiece is placed into the high-frequency induction coil. By precisely controlling the heating power and time, the brazing filler metal melts and fills the joint gap, while the base material does not melt. After cooling, a dense and strong metallurgical bond is formed. After welding, the weld must be visually inspected and subjected to non-destructive testing such as X-ray or ultrasonic testing to ensure that there are no defects such as porosity, slag inclusions, or incomplete penetration.

[0067] The welded copper-iron grafting pipe assembly is placed in the assembly fixture, aligning the upper protrusion 121 of the iron pipe protrusion 12 with the pre-drilled mounting hole or mounting base on the compressor lower housing 4. Resistance welding, such as projection welding, is then performed. Using a specific electrode fixture, one electrode acts on the inner protrusion area of ​​the iron pipe 1, and the other electrode acts on the corresponding position on the outer side of the lower housing 4. A strong current and pressure are applied, generating resistance heat at the contact interface between the protrusion 12 and the housing 4, causing the local metal to reach a plastic or molten state, forming a weld nugget under pressure. The welding parameters—current, time, and pressure—need to be optimized based on the material thickness and protrusion geometry. After welding, strength testing and airtightness checks are required to ensure a reliable connection.

[0068] For those skilled in the art, the present invention is not limited to the details of the above exemplary embodiments, and can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention.

Claims

1. A copper-iron grafting pipe for a fully enclosed compressor, characterized in that, It includes copper pipes and iron pipes. The copper pipes and iron pipes are welded to form a grafting pipe. The iron pipe near the weld is a bulge. One side of the bulge is the weld point connecting the copper pipe and the iron pipe. The bulge is an arc-shaped bulge.

2. The copper-iron grafting pipe of a fully enclosed compressor according to claim 1, characterized in that, The top of the iron pipe bulge is an upward convex part.

3. The copper-iron grafting pipe of a fully enclosed compressor according to claim 2, characterized in that, The upper convex part has a first concave part and a second concave part on its two sides, respectively.

4. The copper-iron grafting pipe of a fully enclosed compressor according to claim 3, characterized in that, The angle between the axis of the first concave part and the plane of the iron pipe is 40° to 70°, and the angle between the axis of the second concave part and the plane of the iron pipe is 40° to 60°.

5. The copper-iron grafting pipe of a fully enclosed compressor according to claim 3 or 4, characterized in that, One side of the second concave portion is the connecting part, which is a small concave pit.

6. The copper-iron grafting pipe of a fully enclosed compressor according to claim 5, characterized in that, One side of the connecting part is the positioning point for the iron pipe.

7. The copper-iron grafting pipe of a fully enclosed compressor according to claim 1, characterized in that, A copper pipe includes a first end face and a second end face, and an iron pipe includes a first end face and a second end face.

8. The copper-iron grafting pipe of a fully enclosed compressor according to claim 7, characterized in that, The second end face of the copper tube abuts against the positioning point of the iron tube, which is located inside the iron tube and consists of several small protruding points.

9. The copper-iron grafting pipe of a fully enclosed compressor according to claim 7 or 8, characterized in that, The first end of the iron pipe is connected to the cover plate assembly inside the compressor, and the first end of the copper pipe is connected to the refrigerator system pipe.

10. The copper-iron grafting pipe of a fully enclosed compressor according to claim 1, characterized in that, The iron pipe protrusion is welded to the lower shell.

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