阅读说明：本技术 管件连接结构 (Pipe fitting connecting structure ) 是由 不公告发明人 于 2019-02-21 设计创作，主要内容包括：管件连接结构,用于制冷系统,包括第一管件本体部、连接部和第二管件本体部,所述第一管件本体部由不锈钢材料制成,所述第二管件本体部由铜质材料制成,所述连接部由铜质材料制成,所述连接部包括内壁部,所述内壁部与所述第二管件本体部的外壁相配合；所述连接部包括外壁部,所述外壁部包括第一外壁部和第二外壁部,所述第二外壁部与所述第一管件本体部的内壁相配合；所述连接部包括大径部和小径部,所述第一外壁部形成于所述大径部的外周壁,所述第二外壁部形成于所述小径部的外周壁,所述大径部的厚度大于所述小径部的厚度,所述大径部的高度H1与所述小径部的高度H2满足关系式：1/4≤H1/H2≤1。本发明能够提高不锈钢管件与铜管件之间的焊接可靠性。(The pipe fitting connecting structure is used for a refrigerating system and comprises a first pipe fitting body part, a connecting part and a second pipe fitting body part, wherein the first pipe fitting body part is made of stainless steel materials, the second pipe fitting body part is made of copper materials, the connecting part comprises an inner wall part, and the inner wall part is matched with the outer wall of the second pipe fitting body part; the connecting portion includes an outer wall portion including a first outer wall portion and a second outer wall portion that is fitted with an inner wall of the first pipe body portion; the connecting portion includes a large diameter portion and a small diameter portion, the first outer wall portion is formed on an outer peripheral wall of the large diameter portion, the second outer wall portion is formed on an outer peripheral wall of the small diameter portion, a thickness of the large diameter portion is greater than a thickness of the small diameter portion, and a height H1 of the large diameter portion and a height H2 of the small diameter portion satisfy a relation: 1/4 is less than or equal to H1/H2 is less than or equal to 1. The invention can improve the welding reliability between the stainless steel pipe fitting and the copper pipe fitting.)

1. The pipe connecting structure is used for a refrigerating system and is characterized by comprising a first pipe body part (1), a connecting part (2) and a second pipe body part (3), wherein the first pipe body part (1) is made of stainless steel materials, the second pipe body part (3) is made of copper materials, the connecting part (2) comprises an inner wall part (23), and the inner wall part (23) is matched with the outer wall of the second pipe body part (3); the connecting portion (2) includes an outer wall portion (24), the outer wall portion (24) includes a first outer wall portion (241) and a second outer wall portion (242), the second outer wall portion (242) is fitted with an inner wall of the first pipe body portion (1); the connecting portion (2) includes a large diameter portion (21) and a small diameter portion (22), the first outer wall portion (241) is formed on an outer peripheral wall of the large diameter portion (21), the second outer wall portion (242) is formed on an outer peripheral wall of the small diameter portion (22), a thickness of the large diameter portion (21) is larger than a thickness of the small diameter portion (22), and a height (H1) of the large diameter portion (21) and a height (H2) of the small diameter portion (22) satisfy a relational expression: 1/5 is less than or equal to H1/H2 is less than or equal to 1.

2. A pipe connection according to claim 1, c h a r a c t e r i z e d in that at least a major part of the inner wall of the connection portion (2) abuts the outer wall of the second pipe body portion (3), at least a major part of the outer wall of the second outer wall portion (242) abuts the inner wall of the first pipe body portion (1), and in that along the axial direction of the pipe connection the projections of the first pipe body portion (1) and the second pipe body portion (3) on the centre axis of the pipe connection at least partly overlap.

3. The pipe connecting structure according to claim 1, wherein a stepped portion (211) is formed between the large diameter portion (21) and the small diameter portion (22), a stepped surface of the stepped portion (211) in an axial direction abuts against an end surface of the first pipe body portion (1) or has a suitable distance, and the small diameter portion (22) at least partially protrudes into the first pipe body portion (1).

4. A pipe connecting structure according to claim 1, wherein the connecting portion (2) and the first pipe body portion (1) are fixed by furnace welding, and a welding material is preset between the connecting portion (2) and the first pipe body portion (1) before furnace welding, and the preset welding material is melted at the time of furnace welding and causes a space between an outer wall of the connecting portion (2) and an inner wall of the first pipe body portion (1) to have the welding material; the connecting part is provided with a positioning part at one side close to the first pipe fitting body part (1), the second pipe fitting body part (3) is positioned through the positioning part, and the connecting part (2) and the second pipe fitting body part (3) are welded and fixed through flame brazing; the melting temperature of the solder for furnace welding is higher than that of the solder for flame brazing.

5. A tube connecting structure according to any one of claims 1 to 4, wherein the connecting portion (2) is an integral structure, the large diameter portion (21) and the small diameter portion (22) are formed by machining from an integral material, and when flame brazing is performed, flame directly heats the large diameter portion (21) and the second tube body portion (3), and the wall thickness (D1) of the large diameter portion (21) and the wall thickness (D2) of the small diameter portion (22) satisfy the relationship: d1 is more than or equal to 1 and less than or equal to 1.5D 2.

6. A pipe connecting structure according to claim 5, wherein said first pipe body portion (1) includes a fitting portion (31) and a flared portion (32), or said first pipe body portion (1) includes a fitting portion (31) and a necked portion, said connecting portion (2) is fitted to said fitting portion (31), and solder is filled between said connecting portion (2) and said fitting portion (31).

7. A pipe connecting structure according to any one of claims 1 to 4, wherein the connecting portion (2) includes a first sleeve portion (201) and a first annular portion (202), the first sleeve portion (201) and the first annular portion (202) are of a split structure, an end surface of the first sleeve portion (201) abuts against an end surface of the first annular portion (202), the first sleeve portion (201) and the first annular portion (202) are both made of a copper material, a thickness of the first sleeve portion (201) is smaller than a thickness of the first annular portion (202), and the first sleeve portion (201), the first annular portion (202), and the first pipe body portion (1) are fixed to form an assembly by furnace welding and then fixed to the second pipe body portion (3) by flame welding.

8. A pipe connection according to claim 7, characterised in that the inner wall of the first sleeve part (201) cooperates with the outer wall of the second pipe body part (3), the inner wall of the first annular part (202) cooperates with the outer wall of the second pipe body part (3), and the end face of the first annular part (202) abuts against the end face of the first pipe body part (1).

9. A pipe connecting structure according to any one of claims 1 to 4, wherein said connecting portion (2) comprises a second sleeve portion (203) and a second annular portion (204), said second sleeve portion (203) and said second annular portion (204) are of a separate structure, said second sleeve portion (203) and said second annular portion (204) are made of a copper material, and said second sleeve portion (203), said second annular portion (204) and said first pipe body portion (1) are fixed to each other by furnace welding to form an assembly, and then fixed to said second pipe body portion (3) by flame brazing welding.

10. The pipe connecting structure according to claim 9, wherein the second sleeve portion (203) includes a bent portion (2031), the bent portion (2031) abuts against one end surface of the second annular portion (204) or has a suitable distance therebetween, the other end surface of the second annular portion (204) abuts against the first pipe body portion (1), an outer wall of the second sleeve portion (203) simultaneously fits an inner wall of the second annular portion (204) and an inner wall of the first pipe body portion (1), and an inner wall of the second sleeve portion (204) fits an outer wall of the second pipe body portion (1).

Technical Field

The invention belongs to the technical field of refrigeration, and mainly relates to connection between two pipelines made of different materials.

Background

Products in the refrigeration technology field include household air conditioners, refrigerators, freezers and the like, generally, copper pipes are used as connecting pipes for connecting two parts of the systems, and in order to be conveniently connected with the copper pipes, a plurality of parts are correspondingly made of copper materials. Such as a pressure vessel, a silencer, a four-way reversing valve and the like are all basic parts in a refrigeration system, and are all connected with the refrigeration system through copper material pipes.

In order to save cost, in the refrigeration technology field, some parts are made of stainless steel materials, such as a four-way reversing valve made of stainless steel materials. Although the structure saves part of cost, in the manufacturing process, the connecting pipe of the stainless steel material of the four-way reversing valve is welded with the copper pipe in the refrigeration system, and the welding characteristics of the copper material and the stainless steel material are greatly different, so that the process difficulty is increased and the welding quality is not easy to guarantee if the welding is simply implemented.

Therefore, how to better realize the reliable connection between the stainless steel pipe fittings and the copper pipes of each part in the refrigeration system is a problem to be solved by the technical personnel in the field.

Disclosure of Invention

The invention provides a pipe fitting connecting structure, which can realize reliable connection between a stainless steel pipe fitting and a copper pipe and is convenient for welding, and in order to realize the purpose, the invention provides the following technical scheme:

a pipe connecting structure for a refrigeration system, comprising a first pipe body part, a connecting part and a second pipe body part, wherein the first pipe body part is made of stainless steel material, the second pipe body part is made of copper material, the connecting part comprises an inner wall part, and the inner wall part is matched with the outer wall of the second pipe body part; the connecting portion includes an outer wall portion including a first outer wall portion and a second outer wall portion that is fitted with an inner wall of the first pipe body portion; the connecting portion includes a large diameter portion and a small diameter portion, the first outer wall portion is formed on an outer peripheral wall of the large diameter portion, the second outer wall portion is formed on an outer peripheral wall of the small diameter portion, a thickness of the large diameter portion is greater than a thickness of the small diameter portion, and a height H1 of the large diameter portion and a height H2 of the small diameter portion satisfy a relation: 1/5 is less than or equal to H1/H2 is less than or equal to 1.

According to the pipe connecting structure provided by the invention, the copper connecting part is arranged between the stainless steel connecting pipe and the copper connecting pipe, the connecting part comprises the large-diameter part and the small-diameter part, the large-diameter part is positioned outside the stainless steel first pipe body part and has a certain height and thickness, so that the pipe connecting structure not only has relatively high strength, but also is beneficial to simultaneously heating the second pipe body part and the large-diameter part by flame when the pipe connecting structure is subjected to flame brazing with the second pipe body part of a system, and the welding effect is relatively more reliable.

Drawings

FIG. 1: the invention provides a schematic diagram of a four-way reversing valve of a first embodiment;

FIG. 2: a cross-sectional schematic view of the four-way reversing valve of the first embodiment;

FIG. 3: enlarged view of part I of FIG. 2;

FIG. 4 is a schematic view of a pipe connection structure of a refrigeration system according to a first embodiment of the present invention;

FIG. 5: a schematic view of a pipe connection structure according to a second embodiment of the present invention;

FIG. 6: the pipe fitting connection structure of the third embodiment of the invention is schematically shown.

Detailed Description

The technical solution of the present invention is explained below with reference to a specific embodiment, and a four-way reversing valve is taken as an example to explain the technical solution and a connection structure of a pipe fitting is specifically explained below by taking a connection pipe of the four-way reversing valve and a copper pipe of a refrigeration system as an example.

FIG. 1 is a schematic representation of a four-way reversing valve according to a first embodiment of the present invention, and FIG. 2 is a schematic cross-sectional view of the four-way reversing valve according to the first embodiment.

As shown in fig. 1 and 2, the four-way reversing valve a1 is used for a refrigeration system such as an air conditioning system and comprises a main valve a11 and a pilot valve a 12; the main valve a11 and the pilot valve a12 may be secured in relative position by a connector bracket assembly a 13. The main valve a11 includes a valve body a115, and the valve body a115 is substantially cylindrical and may be made of a stainless steel material. The valve body a115 is fixedly connected at both ends thereof to the first and second end caps 1201 and 1202, respectively, so that a chamber is formed inside the valve body a 115. The valve body a115 is fixedly connected with a first connection pipe a111 (connected with a high pressure region) connected with a discharge port of the compressor, a second connection pipe a112 (connected with a low pressure region) connected with a suction port of the compressor, a third connection pipe a113 connected with the indoor heat exchanger, and a fourth connection pipe a114 connected with the outdoor heat exchanger.

The valve body a115 is internally and fixedly provided with a valve seat a116, and the valve seat a116 can also be made of stainless steel material. A slide block A118 and a piston A119 which are driven by a connecting rod A117 are further arranged in a valve cavity formed by the valve body A115, the first end cover 1201 and the second end cover 1202, wherein the piston A119 and the connecting rod A117 can be fixedly connected into a module, the pistons A119 are in a pair and are respectively positioned at two ends of the connecting rod A117, and thus, the valve cavity is divided into three middle cavity bodies B1, a left cavity body B2 and a right cavity body B3 which are isolated from each other by the piston connecting rod assembly. The valve seat a116 contacts and supports the slider a118 such that the slider a118 engages the upper surface of the valve seat a 116. Under the action of the pressure difference, the piston connecting rod assembly can push the piston connecting rod assembly to move leftwards or rightwards, so that in a certain working state, the space inside the second connecting pipe A112 is communicated with the space inside the third connecting pipe A113, and the state is shown in FIG. 2; in another operating state, the piston-connecting rod assembly moves to the right, so that the space inside the second connecting pipe a112 is communicated with the space inside the fourth connecting pipe a 114.

The pilot valve A12 includes a pilot valve body A121, a core A124 and a return spring A125 are disposed within the pilot valve body 121, and a sliding bowl A123 is fixedly connected to the core A124. The pilot valve a12 is fixedly connected with a first capillary tube d connected with the first connecting tube a111 of the main valve a11, i.e. the inner cavity of the pilot valve a12 is correspondingly communicated with the middle cavity B1 (i.e. high pressure area) of the valve body a115 of the main valve a 11; the pilot valve a12 is internally and fixedly provided with a small valve seat a122, the sliding bowl a123 is bowl-shaped and can slide leftwards or rightwards on the surface of the small valve seat a122, the small valve seat a122 is provided with three valve ports, and a third capillary tube e connected with a third connecting tube a113 of the main valve a11, a second capillary tube s connected with a second connecting tube a112 of the main valve a11 and a fourth capillary tube c connected with a fourth connecting tube a114 of the main valve a11 are respectively and fixedly arranged from left to right.

When the refrigeration system needs to refrigerate, the electromagnetic coil (not shown in the figure) is not energized, the core iron a124 in the cavity of the pilot valve a12 drives the sliding bowl a123 to move to the left under the spring force of the return spring a125, as shown in the position of fig. 2, the capillary e is communicated with the internal space of the capillary s, the capillary c is communicated with the internal space of the capillary d, so that the left cavity B2 of the main valve a11 is a low-pressure region, the right cavity B3 is a high-pressure region, a pressure difference is formed between the left cavity and the right cavity of the main valve a11, so that the sliding block a118 and the piston a119 are pushed to the left, so that the internal spaces of the third connecting pipe a113 and the second connecting pipe a112 are communicated, the first connecting pipe a111 is communicated with the internal space of the fourth connecting pipe a: the compressor discharge port → the first connection pipe a111 → the intermediate cavity B1 → the fourth connection pipe a114 → the outdoor heat exchanger → the throttling member → the indoor heat exchanger → the third connection pipe a113 → the inner cavity of the slider a118 → the second connection pipe a112 → the compressor suction port, and the refrigeration system is in a refrigeration operation state, that is, the state shown in fig. 2.

When the refrigeration system needs to heat, the electromagnetic coil is powered on, the core iron a124 in the cavity of the pilot valve a12 overcomes the spring force of the return spring a125 to drive the sliding bowl a123 to move to the right, so that the capillary c is communicated with the internal space of the capillary s, the capillary e is communicated with the internal space of the capillary d, the left cavity B2 of the main valve a11 is a high-pressure region, the right cavity B3 is a low-pressure region, a pressure difference is formed between the left cavity and the right cavity of the main valve a11, the sliding block a118 and the piston a119 are pushed to the right, so that the internal spaces of the fourth connecting pipe a114 and the second connecting pipe a112 are communicated, the first connecting pipe a111 is communicated with the internal space of the third connecting pipe a113, and at: the compressor discharge port → the first connection pipe a111 → the middle chamber B1 → the third connection pipe a113 → the indoor heat exchanger → the throttling element → the outdoor heat exchanger → the fourth connection pipe a114 → the inner chamber of the slider a118 → the second connection pipe a112 → the compressor suction port, and the refrigeration system is in a heating operation state.

As described above, the direction of the main valve a11 can be switched by the cooperation of the pilot valve a12 and the solenoid coil, and the refrigerant flow direction can be switched, thereby switching the heating operation state and the cooling operation state of the refrigeration system.

In the four-way selector valve A1, the valve body a115 and the valve seat a116 of the main valve, and the pipe main bodies of the first connection pipe a111, the second connection pipe a112, the third connection pipe a113, and the fourth connection pipe a114 may be made of stainless steel. When the main bodies of the four connecting pipes are made of stainless steel materials, the problem of how to weld the main bodies with copper pipes in a refrigeration system is involved.

The structure of the third adapter tube a113 is described in detail below by taking the third adapter tube a113 as an example, and those skilled in the art can understand that the structure of the third adapter tube a113 can be completely applied to the first adapter tube a111, the second adapter tube a112, and the fourth adapter tube a 114.

As shown in fig. 3, the third joint pipe a113 includes a first pipe body portion 1 and a connecting portion 2, wherein the first pipe body portion 1 is made of a stainless material, and the connecting portion 2 is made of a copper material. The connection 2 is generally tubular and includes an inner wall 23 for mating with copper tubing in the refrigeration system. The coupling portion 2 further comprises an outer wall portion 24, a portion of the outer wall portion 24 engaging a portion of the inner wall of the first tubular body portion 1. Specifically, the connecting portion 2 may be formed by molding a single piece of material, and includes a large diameter portion 21 and a small diameter portion 22, and the thickness of the large diameter portion 21 in the radial direction is larger than that of the small diameter portion 22 in the radial direction. The wall thickness D1 of the large diameter portion 21 and the wall thickness D2 of the small diameter portion 22 satisfy the relationship: d1 is more than or equal to 1 and less than or equal to 1.5D 2.

Thus, a first outer wall portion 241 is formed on the outer peripheral wall of the large diameter portion 21, and a second outer wall portion 242 is formed on the outer peripheral wall of the small diameter portion 22, and the small diameter portion 22 is inserted into the first pipe body portion 1 such that at least most of the outer wall of the second outer wall portion 241 is fitted with the inner wall of the first pipe body portion 1. In the present embodiment, the height H1 of the large diameter portion 21 in the axial direction of the drawing and the height H2 of the small diameter portion 22 in the axial direction of the drawing satisfy the relation 1/5. ltoreq.H 1/H2. ltoreq.1.

A step portion 211 is formed between the large diameter portion 21 and the small diameter portion 22, and the step portion 211 may have a right-angled step shape. Of course, for reasons of manufacturing process, the stepped portion may be rounded, as shown in fig. 3. The stepped portion 211 abuts against the end surface of the first pipe body portion 1 at a stepped surface along the axial direction of the connecting portion 2 or has a suitable distance, and the small-diameter portion 22 at least partially protrudes into the first pipe body portion 1.

The connecting portion 2 and the first pipe body portion 1 can be fixed by furnace welding, specifically, before furnace welding, a welding material for welding is preset between the connecting portion 2 and the first pipe body portion 1, the connecting portion 2 and the first pipe body portion 1 are fixed, then the fixed assembly is placed in a tunnel furnace, the preset welding material is melted at a high temperature, and a space between an outer wall of the connecting portion 2 and an inner wall of the first pipe body portion 1 is filled with the welding material, so that the welding and the fixing of the connecting portion 2 and the first pipe body portion 1 are realized.

The connecting portion 2 is provided with a positioning portion 25 at a side close to the first pipe body portion 1, and the positioning portion 25 can be used for positioning when being matched with a refrigeration system pipe (detailed below). Of course, the positioning portion 25 may not be provided, and the connection portion 2 and the refrigeration system pipe may be positioned in another manner.

The four-way reversing valve and the pipe connection structure thereof provided by the embodiment adopt the copper connection part, the connection part is provided with the large-diameter part and the small-diameter part, wherein, at least the large part of the small-diameter part is matched with the first pipe fitting body part made of stainless steel, and the large-diameter part positioned outside the first pipe fitting body part is provided with relatively large wall thickness, has relatively high strength, is not easy to be damaged or deformed by external force in the transportation or circulation process, and is convenient to be welded with the pipe of the refrigeration system. The large-diameter part has a certain height, so that the four-way reversing valve can be conveniently heated and heat can be transferred to the small-diameter part in the welding process of flame brazing of the four-way reversing valve and the refrigeration system piping, and the reliability of flame brazing is improved.

The four-way reversing valve with a stainless steel connecting pipe is described above as an example, it should be noted that the core of this embodiment lies in the matching manner of the stainless steel connecting pipe and the connecting portion, and there is no need to limit the specific component structure inside the four-way reversing valve, and the above description of the internal structure and operation process of the four-way reversing valve is only for facilitating the understanding of the basic function and operation principle of the four-way reversing valve by those skilled in the art, and is not meant to limit the core of the present invention to the above four-way reversing valve structure. Meanwhile, in light of the above teachings, those skilled in the art can understand that the above-mentioned fitting manner of the stainless steel connection tube and the copper connection portion can be completely applied to other valves obtained by simple deformation, such as a three-way valve, a reversible valve, etc., and even to various pressure vessels made of stainless steel material, such as a liquid reservoir, a muffler, etc.

As mentioned above, since the above-mentioned stainless steel adapter and copper connection can be used in any component with a stainless steel adapter of a refrigeration system, the following embodiments do not limit the specific product to which the stainless steel adapter is applied, and the stainless steel adapter is still named as "the first tube body portion" for ease of understanding.

A pipe connection structure constructed in a specific manner in which the first embodiment described above is applied to a refrigeration system will be described below with reference to fig. 4. Referring to fig. 4, fig. 4 is a schematic view of a pipe connection structure applied to a refrigeration system according to a first embodiment of the present invention.

As shown in fig. 4, the pipe connection structure includes a first pipe body portion 1, a connection portion 2, and a second pipe body portion 3, wherein the first pipe body portion 1 may be used as a connection pipe of all components of the refrigeration system made of stainless steel, such as a four-way reversing valve, a liquid reservoir, a muffler, and the like, and the second pipe body portion 3 is used as a part of a pipeline of the refrigeration system and is welded and fixed to the connection pipe of the components of the refrigeration system, so as to connect the components of the refrigeration system to the refrigeration system. The second tube body 3 is made of copper.

Because the first pipe body 1 is made of stainless steel material and the second pipe body 3 is made of copper material, the first pipe body 1 and the second pipe body must be welded and fixed during assembly, and in order to improve the assembly efficiency, the first pipe body 1 is fixedly connected with the connecting part 2, and the connecting part 2 is made of copper material. Therefore, the stainless steel connecting pipe of the refrigeration system component is welded and fixed with the connecting part 2 before leaving the factory, and when the system is assembled, the copper second pipe body part 3 and the copper connecting part 2 are only required to be welded.

In the present embodiment, the first pipe body 1 is a connection pipe of the four-way reversing valve, and includes a fitting portion 31 and a flared portion 32, wherein the fitting portion 31 is used for fitting with the connecting portion 2, and after the welding is completed, the solder is filled between the connecting portion 2 and the fitting portion 31. Of course, it will be understood by those skilled in the art that when the first pipe body 1 is used as a connecting pipe or a connecting port of other refrigeration components, the flared portion 32 may be replaced by a necking portion, such as a container product like a liquid container or a muffler, and a fitting portion is usually formed after the necking portion, and the fitting portion is used for fitting with the connecting portion and is fixed by welding.

The coupling part 2 is generally tubular and includes an inner wall 23 for co-operation with the outer wall of the second tubular body part 3. The coupling portion 2 further comprises an outer wall portion 24, a portion of the outer wall portion 24 engaging a portion of the inner wall of the first tubular body portion 1. Specifically, the connecting portion 2 may be formed by molding a single piece of material, and includes a large diameter portion 21 and a small diameter portion 22, and the thickness of the large diameter portion 21 in the radial direction is larger than that of the small diameter portion 22 in the radial direction. The wall thickness D1 of the large diameter portion 21 and the wall thickness D2 of the small diameter portion 22 satisfy the relationship: d1 is more than or equal to 1 and less than or equal to 1.5D 2.

Thus, a first outer wall portion 241 is formed on the outer peripheral wall of the large diameter portion 21, and a second outer wall portion 242 is formed on the outer peripheral wall of the small diameter portion 22, and the small diameter portion 22 is inserted into the first pipe body portion 1 such that at least most of the outer wall of the second outer wall portion 241 is fitted with the inner wall of the first pipe body portion 1. In the present embodiment, the height H1 of the large diameter portion 21 in the axial direction of the drawing and the height H2 of the small diameter portion 22 in the axial direction of the drawing satisfy the relation 1/5. ltoreq.H 1/H2. ltoreq.1.

A step portion 211 is formed between the large diameter portion 21 and the small diameter portion 22, and the step portion 211 may have a right-angled step shape. Of course, for reasons of manufacturing process, the stepped portion may be rounded, as shown in fig. 4. The stepped portion 211 abuts against the end surface of the first pipe body portion 1 at a stepped surface along the axial direction of the connecting portion 2 or has an appropriate distance.

The connecting portion 2 and the first pipe body portion 1 may be fixed by furnace welding, specifically, a welding material for welding is preset between the connecting portion 2 and the first pipe body portion 1 before furnace welding, and the connecting portion 2 and the first pipe body portion 1 are fixed, then the fixed assembly is placed in a tunnel furnace, the preset welding material is melted at a high temperature, and a space between an outer wall of the connecting portion 2 and an inner wall of the first pipe body portion 1 is filled with the welding material, thereby realizing welding and fixing of the two.

The second pipe body 3 is made of copper material and is substantially tubular, and after the connecting portion 2 and the first pipe body 1 are welded in a furnace to form a component, the second pipe body 3 and the component are welded and fixed. In this embodiment, the connecting portion 2 is provided with a positioning portion 25 on a side close to the first pipe body portion 1, and when the second pipe body portion 3 is inserted into the connecting portion 2, the positioning can be performed by the positioning portion 25. Of course, the positioning portion 25 may not be provided, and the connecting portion 2 and the second pipe body portion 3 may be positioned by another method such as dotting on the outer wall. At least most of the inner wall of the connecting portion 2 abuts the outer wall of the second tubular body portion 3, and at least most of the outer wall of the second outer wall portion 242 abuts the inner wall of the first tubular body portion 1. In the axial direction of the pipe connection, the projections of the first pipe body part 1 and the second pipe body part 3 on the central axis of the pipe connection at least partially overlap, i.e. there is at least one cross section, which can simultaneously pass through the first pipe connection part 1 and the second pipe connection part 3.

The connecting portion 2 and the second pipe body portion 3 are fixed by flame brazing welding. The melting temperature of the solder in the furnace is higher than that in the flame brazing, so that the welding seam between the connecting portion 2 and the first pipe body portion 1 is not broken when the flame brazing is performed. After the connecting portion 2 and the first pipe fitting body portion 1 are welded and fixed through furnace welding, the second pipe fitting body portion 3 is inserted into the connecting portion 2 to be positioned as an assembly, and solder X is added at the matching position of the connecting portion and the first pipe fitting body portion 1 in a feeding mode. The heat of the large diameter part can be rapidly transferred to the small diameter part during the flame brazing, and the second pipe body part can simultaneously transfer the heat from the heated part to the upper end part of the second pipe body part as shown in fig. 4. That is, the heat generated by the flame can be rapidly transferred from the region shown by Q1 to the region shown by Q2, which is advantageous for improving the efficiency and reliability of the welding. If not set up the major diameter portion, only set up the minor diameter portion that is located first pipe fitting body portion inside, because stainless steel material's coefficient of heat conductivity is lower, the heat is difficult to be transmitted to the minor diameter portion by first pipe fitting body portion, then when implementing flame brazing, the heat of minor diameter portion can only mostly be followed second pipe fitting body portion and transmitted to need higher flame temperature.

The pipe fitting connection structure that above-mentioned embodiment provided, owing to adopted the connecting portion of copper, connecting portion have major diameter portion and minor diameter portion, wherein, minor diameter portion major diameter portion at least and stainless steel's first pipe fitting this somatic part cooperation, and the major diameter portion that lies in first pipe fitting this somatic part outside then has relatively great wall thickness, has relatively higher intensity, is difficult for receiving external force in transportation or circulation process and causes damage or deformation, and the convenience is welded with refrigerating system's piping. And the large diameter part has a certain height, so that the large diameter part can be conveniently heated and transfer heat to the small diameter part in the welding process of flame brazing with the second pipe body part, thereby improving the efficiency and reliability of flame brazing.

The second embodiment will be described with reference to fig. 5. Referring to fig. 5, fig. 5 is a schematic view illustrating a pipe connecting structure according to a second embodiment of the present invention.

In order to more clearly illustrate the difference between the pipe connecting structure of the second embodiment and the first embodiment, the same reference numerals are used hereinafter for the components of the two embodiments that have the same structure and function, and the description will be focused on the difference therebetween.

The first and second tube body portions 1 and 3 of this embodiment are the same as those of the first embodiment, i.e., the first tube body portion 1 is made of stainless steel material, and the second tube body portion 3 is made of copper material as a pipe of the refrigeration system.

In the present embodiment, the connecting portion 2 includes a first sleeve portion 201 and a first annular portion 202, the first sleeve portion 201 and the first annular portion 202 are separate structures, and both are made of a copper material. An end surface of the first sleeve part 201 abuts against an end surface of the first annular part 202, and the thickness of the first sleeve part 201 is smaller than the thickness of the first annular part 202. The inner wall of the first sleeve portion 201 is fitted to the outer wall of the second pipe body portion 3, the inner wall of the first annular portion 202 is fitted to the outer wall of the second pipe body portion 3, and the end face of the first annular portion 202 abuts against the end face of the first pipe body portion 1. During assembly, the first sleeve portion 201, the first annular portion 202 and the first pipe body portion 1 are first placed in a furnace to be furnace-welded to form an assembly, and then are fixed to the second pipe body portion 3 made of copper by flame brazing.

Thus, in the present embodiment, the first annular portion 202 constitutes a large diameter portion, the first sleeve portion 201 constitutes a small diameter portion, the inner wall of the first annular portion 202 and the inner wall of the first sleeve portion 201 together constitute an inner wall portion of the connecting portion 2, the outer wall of the first annular portion 202 constitutes a second outer wall portion, the outer wall of the first sleeve portion 201 constitutes a first outer wall portion, the first annular portion 202 and the outer wall of the first sleeve portion 201 together constitute an outer wall portion of the connecting portion 2,

the first collar portion 201 and the first annular portion 202 are welded and fixed to the first tube body 1 by furnace welding, and then the second tube body 3 is inserted into the connecting portion 2 to be positioned as a unit, and solder X is added at the matching position of the first collar portion and the first annular portion by feeding. Because the heat of the first annular part can be rapidly transferred to the first sleeve part during the flame brazing, and the second pipe body part can also transfer the heat from the heated part to the upper end part of the second pipe body part shown in fig. 5. That is, the heat generated by the flame can be rapidly transferred from the region shown by Q1 to the region shown by Q2, which is advantageous for improving the efficiency and reliability of the welding.

According to the pipe connecting structure provided by the embodiment, the assembly of the first pipe body part and the connecting part can conveniently transfer heat to the small-diameter part in the welding process of flame brazing with the second pipe body part, so that the efficiency and the reliability of flame brazing are improved.

The third embodiment will be described with reference to fig. 6. Referring to fig. 6, fig. 6 is a schematic view of a pipe connecting structure according to a third embodiment of the present invention.

In order to more clearly illustrate the difference between the pipe connecting structure of the third embodiment and the first embodiment, the same reference numerals are used hereinafter for the components of the two embodiments that have the same structure and function, and the description will be focused on the difference therebetween.

The first and second tube body portions 1 and 3 of this embodiment are the same as those of the first embodiment, i.e., the first tube body portion 1 is made of stainless steel material, and the second tube body portion 3 is made of copper material as a pipe of the refrigeration system.

In the present embodiment, the connecting portion 2 includes the second sleeve portion 203 and the second annular portion 204, the second sleeve portion 203 and the second annular portion 204 are of a separate structure, and both are made of a copper material. The second sleeve portion 203 includes a bent portion 2031, and when the second sleeve portion 203 is engaged with the second annular portion 204, the bent portion 2031 abuts against one end surface of the second annular portion 204 or has a suitable distance, and the other end of the second annular portion 204 abuts against the end surface of the first pipe body portion 1. The outer wall of the second sleeve part 203 fits both the inner wall of the second annular part 204 and part of the inner wall of the first pipe body part 1, and the inner wall of the second sleeve part 204 fits part of the outer wall of the second pipe body part 1.

Thus, in the present embodiment, the second annular portion 204 and a part of the second sleeve portion 203 constitute a large diameter portion, the other part of the second sleeve portion 203 constitutes a small diameter portion, the inner wall of the second sleeve portion 203 constitutes an inner wall portion of the connecting portion 2, the outer wall of the second annular portion 202 constitutes a second outer wall portion of the connecting portion 2, a part of the outer wall of the second sleeve portion 203 constitutes a first outer wall portion,

during assembly, the second sleeve part 203, the second annular part 204 and the first pipe body part 1 are placed into a furnace to be furnace-welded to form an assembly, and then are fixed to the second pipe body part 3 made of copper by flame brazing. After the second sleeve part 203 and the second annular part 204 are welded and fixed to the first pipe body 1 by furnace welding, the second pipe body 3 is inserted into the connecting part 2 and positioned as a unit, and the solder X is added at the matching position of the two by feeding, when flame brazing is performed, the flame directly heats the second annular part 204, the bent part 2031 and the second pipe body 3 (in the direction of the arrow shown in fig. 6), so that the solder X is melted and flows along the matching surface between the second sleeve part 203 and the second pipe body 3, and finally the welding and fixing are completed. Since the heat of the second annular portion 204 can be rapidly transferred to the first sleeve portion during the flame brazing, the second pipe body portion 3 can also transfer the heat from the heated portion to the upper end portion thereof as shown in fig. 6. That is, the heat generated by the flame can be rapidly transferred from the region shown by Q1 to the region shown by Q2, which is advantageous for improving the efficiency and reliability of the welding.

According to the pipe connecting structure provided by the embodiment, the assembly of the first pipe body part and the connecting part can conveniently transfer heat to the small-diameter part in the welding process of flame brazing with the second pipe body part, so that the efficiency and the reliability of flame brazing are improved.

It should be noted that, the stainless steel material described in the present application includes stainless steel and its alloy, and the copper material includes copper alloy material with copper material as core. The terms of orientation such as up, down, left and right are used in the specification and drawings for convenience of description, and are not meant to limit the scope of protection. The use of the ordinal numbers such as "first," "second," etc., in the present application to refer to a component is for convenience in distinguishing between different components and not for indicating a sequential or chronological order of the components.

The above is only an exemplary preferred embodiment for better illustrating the technical solution of the present invention, and it should be noted that, for those skilled in the art, several modifications and decorations can be made without departing from the principle of the present invention, and all such modifications and decorations should be regarded as the protection scope of the present invention.