CONDUCTING FOR AN AIR CONDITIONING CIRCUIT

Abstract

The invention relates to a conduit (1) for an air conditioning circuit, in particular for a motor vehicle, comprising: - a first pipe (2) having a longitudinal axis (X) and comprising a corrugated conduit (6) comprising a first metallic material and an outer sheath (7, 8) arranged coaxially around the corrugated conduit (6), - a second pipe (3) comprising a second metallic material different from the first metallic material, and - a metallic connector (4) connecting the second pipe (3) to the first pipe (2), characterized in that the connector (4) comprises a first tubular portion (10) comprising a material identical or similar to the first material and welded to the corrugated conduit (6), and a second tubular portion (11) comprising a material identical or similar to the second material and welded to the second pipe (3). (Short figure: 1)

Description

Title of the invention: CONDUCT FOR AN AIR CONDITIONING CIRCUIT Technical field of the invention

[0001] The invention relates to the technical field of pipes for air conditioning circuits.

[0002] In particular, the invention relates to the technical field of pipes for air conditioning circuits of motor vehicles. Technical background

[0003] A motor vehicle, for example, typically includes an air conditioning system. The air conditioning system includes pipes for transporting a refrigerant.

[0004] The refrigerant used in air conditioning systems is a gas from the hydrofluoroolefin (HFO) family, such as 2,3,3,3-tetrafluoropropene (1234yf). This type of gas has an environmental impact that may be incompatible with certain national environmental regulations.

[0005] In order to comply with these environmental regulations, it has been proposed to replace 2,3,3,3-tetrafluoropropene with carbon dioxide, known under the reference R744. Indeed, it has been demonstrated that such a gas does not contain per- and polyfluoroalkyl substances (PFAS) compared to 2,3,3,3-tetrafluoropropene.

[0006] The operation of the air conditioning circuit containing carbon dioxide requires operating pressures and temperatures higher than those used for transporting 2,3,3,3-tetrafluoropropene. The air conditioning circuit pipes can therefore be subjected to internal pressures exceeding 100 bar and temperatures exceeding 150°C.

[0007] The configuration of the pipes generally used in air conditioning systems does not necessarily allow them to withstand such pressure and temperature conditions. Furthermore, carbon dioxide has a different chemical composition than 2,3,3,3-tetrafluoropropene, and the configuration of the pipes transporting this gas is not necessarily chemically compatible with the transport of carbon dioxide.

[0008] In this context, document FR-A1-2885398 proposes a conduit for transporting a carbon dioxide refrigerant for air conditioning systems. According to this document, the conduit comprises a first flexible hose connected to a second rigid hose.

[0009] The first pipe has a longitudinal axis and comprises a corrugated metallic conduit and an outer sheath arranged coaxially around the corrugated conduit. The corrugated conduit comprises stainless steel.

[0010] The second metal pipe extends along the longitudinal axis and comprises an aluminum.

[0011] According to this document, the first and second pipes are connected to each other by a metal connector. The connector comprises, according to this document, stainless steel.

[0012] To connect the connector to the first and second pipes, the connector is welded to both the first and second pipes. The weld is, for example, a brazing or induction weld.

[0013] Although very effective since it allows the transport of carbon dioxide under given pressure and temperature conditions, this solution does not give complete satisfaction.

[0014] Indeed, the connector is welded to the first and second pipes. However, welding the stainless steel connector to the second aluminum pipe presents numerous challenges due to the difference in properties between these two materials.

[0015] Consequently, the manufacture of such a pipe is tedious, long and the mechanical properties of the pipe at the end of the welding stage are not necessarily in accordance with expectations.

[0016] In this context, there is a need to provide a conduit for an air conditioning circuit that is compatible with the transport of a refrigerant fluid under given pressure and temperature conditions, while being easily and quickly feasible. Summary of the invention

[0017] To this end, the invention proposes a conduit for an air conditioning circuit, in particular for a motor vehicle, comprising:

[0018] - a first pipe having a longitudinal axis and comprising a corrugated conduit comprising a primary metallic material and an external sheath arranged coaxially around the corrugated conduit,

[0019] - a second pipe comprising a second metallic material different from the first metallic material, and

[0020] - a metal connector linking the second pipe to the first pipe.

[0021] The conduit according to the invention is remarkable in that the connector comprises a first tubular portion made of a material identical or similar to the first material and welded to the corrugated conduit, and a second portion tubular tube comprising a material identical or similar to the second material and connected by welding to the second pipe.

[0022] Thanks to the connector according to the invention, in particular thanks to its bimetallic character, it is now possible to connect the connector to both the first pipe and the second pipe in a simple and reliable way.

[0023] Indeed, the first portion of the connector has a material identical or similar to the material of the corrugated conduit and the second portion of the connector has a material identical or similar to the second pipe.

[0024] By “identical material”, it is understood that the compositions of the two materials are the same.

[0025] By “similar material”, it is understood that the compositions of the two materials may differ, but that the predominant metallic compound present in the composition is identical in both compositions.

[0026] Thus, two aluminum-based compositions with differing additional compounds are considered, within the meaning of the present invention, to be similar materials. Two aluminum-based compositions with identical additional compounds are considered, within the meaning of the present invention, to be identical materials.

[0027] Thanks to such a configuration, it is possible to overcome the disadvantages associated with assembling parts of distinct materials and therefore to connect each of these portions to each of the pipes by means of a conventional weld.

[0028] The mechanical resistance of the connector, and therefore of the conduit, is thus greatly improved.

[0029] The connector according to the invention can withstand internal pressures of up to 170 bar and temperatures of up to 180°C. It also has a burst resistance of 340 bar.

[0030] Also, the manufacturing process for such a pipe is greatly facilitated.

[0031] The invention may comprise one or more of the following features, taken individually or in combination with each other:

[0032] - the first material comprises stainless steel,

[0033] - the second material is aluminum-based,

[0034] - the first portion is connected to a longitudinal end of the corrugated conduit,

[0035] - the first portion has a first longitudinal end connected to the longitudinal end of the corrugated conduit,

[0036] - the first and second portions are joined together by welding or shrink fitting or screwing,

[0037] - the second pipe has a longitudinal end located inside the second portion.

[0038] The invention also relates to a method for manufacturing a pipe according to any one of the preceding characteristics, characterized in that the method comprises the following chronological steps:

[0039] (a) provide the first and second portions,

[0040] (b) weld the first portion to the corrugated conduit, and

[0041] (c) weld the second portion to the second pipe.

[0042] The invention may comprise one or more of the following features, taken individually or in combination with each other:

[0043] - between step (a) and (b), the process comprises the following step (a'):

[0044] (a2) weld the first and second portions together,

[0045] - after step (c), the process comprises the following step (d):

[0046] (d) assemble the first and second portions together by shrink fitting or by screwing. Brief description of the figures

[0047] Other features and advantages will become apparent from the following description of non-limiting embodiments of the invention with reference to the accompanying drawings in which:

[0048] [Fig. 1] is a longitudinal cross-sectional view of a pipe according to a first embodiment of the invention,

[0049] [Fig.2] is a longitudinal cross-sectional view of a conduit according to another embodiment of the invention,

[0050] [Fig. 3] is a longitudinal cross-sectional view of a pipe according to another embodiment,

[0051] Figure 4 is a longitudinal cross-sectional view of a pipe according to another embodiment,

[0052] [Fig.5] is a synoptic diagram of a method for manufacturing a pipe according to the invention. Detailed description of the invention

[0053] Figures 1 to 4 represent a conduit 1 according to different embodiments of the invention. The conduit 1 has a longitudinal axis X.

[0054] In the present invention, the terms "interior", "internal", "exterior", "external", are understood with respect to a transverse axis Y perpendicular to the longitudinal axis X, and with respect to the distance of the longitudinal axis X along this transverse axis Y. The terms "exterior" and "external" are understood as relatively further from the longitudinal axis X along the transverse axis Y, while the terms "interior", "interior" are understood as relatively closer to the longitudinal axis X along the transverse axis Y.

[0055] Pipe 1 is intended for the transport of a refrigerant. The fluid is, for example, a gas. The gas includes, for example, carbon dioxide, also known by the reference R744.

[0056] The transported fluid is for example at a pressure between 50 bar and 180 bar and at a temperature between 50°C and 200°C.

[0057] The conduit 1 comprises a first pipe 2, a second pipe 3 and a connector 4 linking the first and second pipes 2, 3 together.

[0058] The first pipe 2 extends around and along the longitudinal axis X. The first pipe 2 extends longitudinally between a first end 5a and an opposite second end 5b. The first and second ends 5a, 5b are annular and centered on the longitudinal axis X.

[0059] The first pipe 2 is of the multilayer type. The first pipe 2 is flexible. It comprises, from the inside out, a corrugated conduit 6, a first outer sheath 7 situated coaxially around the corrugated conduit 6 and optionally a second outer sheath 8 situated around the first outer sheath 7.

[0060] The corrugated conduit 6 extends longitudinally between the first and second ends 5a, 5b of the first pipe 2. The corrugated conduit 6a has an internal passage 6a for the circulation of the refrigerant fluid which extends longitudinally between the first and second ends 5a, 5b of the first pipe 2.

[0061] The corrugated conduit 6 has undulations 6b on its external surface which preferably extend between the first and second ends of the first pipe 2.

[0062] The corrugated conduit 6 comprises a first metallic material. The first metallic material is stainless steel.

[0063] The first outer sheath 7 advantageously extends longitudinally between the first and second ends 5a, 5b of the first pipe 2. The first outer sheath 7 thus covers the corrugated conduit 6.

[0064] The first sheath 7 comprises a metallic material. The metallic material is, for example, chosen from stainless steels.

[0065] The first sheath 7 has a thickness, for example, between 0.1 mm and 0.5 mm.

[0066] The first sheath 7 advantageously comprises a braid of metallic wires.

[0067] The second sheath 8 is the outermost layer of the first pipe 2. It covers the first sheath 7. The second sheath 8 extends advantageously longitudinally between the first and second ends 5a, 5b of the first pipe 2.

[0068] The second sheath 8 comprises a metallic material. The metallic material is, for example, chosen from stainless steels.

[0069] The second sheath 8 has a thickness, for example, between 0.1 mm and 0.5 mm mm.

[0070] The second sheath 8 advantageously comprises a braid of metallic wires.

[0071] The first pipe 2 may further comprise a third sheath 8' arranged around the second sheath 8. The third sheath 8' comprises, for example, a metallic material, such as stainless steel.

[0072] The first pipe 2 may further comprise a fourth sheath situated around the third sheath 8'. The fourth sheath comprises, for example, a polymer material, such as a thermoplastic.

[0073] The second pipe 3 is rigid. The second pipe 3 extends around and along the longitudinal axis X. The second pipe 3 is axially aligned with the first pipe 2. The second pipe 3 extends longitudinally between a first end 9a and an opposite second end 9b. The first and second ends 9a, 9b are annular and centered on the longitudinal axis X.

[0074] The second pipe 3 comprises a second metallic material. The second metallic material is different from the first metallic material of the corrugated conduit 6. The second metallic material is preferably aluminum-based, and is in particular aluminum or an aluminum alloy.

[0075] The second pipe 3 has an internal diameter substantially equal to an internal diameter of the corrugated conduit 6.

[0076] The second pipe 3 has an internal passage 3a for the circulation of the refrigerant fluid which extends longitudinally between the first and second ends 9a, 9b of the second pipe 3.

[0077] The first and second pipes 2, 3 are connected to each other by the connector 4. The connector 4 extends along and around the longitudinal axis X. It is located axially between the first and second pipes 2, 3.

[0078] Connector 4 has an internal passage 4a for the circulation of the refrigerant. This internal passage 4a fluidly connects the internal passages 6a, 3a of the first and second pipes 2, 3. The internal passages 6a, 4a, 3a are annular and centered on the longitudinal axis X. They are thus aligned along the longitudinal axis X.

[0079] According to the invention, the connector 4 is bi-metallic. The connector 4 thus comprises a first portion 10 comprising a metallic material and a second portion 11 comprising another metallic material different from the metallic material of the first portion 10.

[0080] The metallic material of the first portion 10 is identical or similar to the first metallic material of the corrugated conduit 6. The metallic material of the first portion 10 thus preferably comprises stainless steel.

[0081] By “identical material”, it is understood that the compositions of the two materials are the same.

[0082] By “similar material”, it is understood that the compositions of the two materials may differ, but that the predominant metallic compound present in the composition is identical in both compositions.

[0083] Thus, two steels are considered, within the meaning of the present invention, to be similar materials when the proportions of the alloying elements differ between the two steels. Two steels are considered, within the meaning of the present invention, to be identical materials when the composition of the two steels is the same.

[0084] The first portion 10 extends along the longitudinal axis X between a first end 12a and a second opposite end 12b. The first and second ends 12a, 12b are annular and centered on the longitudinal axis X.

[0085] The first portion 10 is connected to the first pipe 2. According to the invention, the first portion 10 is fixed by welding to the corrugated conduit 6. In particular, the first end 12a of the first portion 10 of the connector 4 is welded to the second end 5b of the first pipe 2.

[0086] The weld is annular. It is for example a laser weld or an arc weld known by the English acronym TIG.

[0087] The metallic material of the second portion 11 is identical or similar to the second metallic material of the second pipe 3. The metallic material of the second portion 11 thus preferably comprises an aluminum-based material, such as aluminum or an aluminum alloy.

[0088] By “identical material”, it is understood that the compositions of the two materials are the same.

[0089] By "similar material" it is understood that the compositions of the two materials may differ, but that the metallic compound predominantly present in the composition is identical in both compositions.

[0090] Thus, two aluminum-based compositions with differing additional compounds are considered, within the meaning of the present invention, to be similar materials. Two aluminum-based compositions with identical additional compounds are considered, within the meaning of the present invention, to be identical materials.

[0091] The second portion 11 extends along the longitudinal axis X between a first end 13a and an opposite second end 13b. The first and second ends 13a, 13b are annular and centered on the longitudinal axis X.

[0092] The second portion 11 may include an internal annular shoulder 14.

[0093] The second portion 11 is connected to the second pipe 3. According to the invention, the second portion 11 is fixed by welding to the second pipe 3. In particular, the second end 13b of the second portion 11 of the connector 4 is welded to the second pipe 3.

[0094] The weld is annular. It is, for example, a laser weld or a braze.

[0095] Preferably, the second pipe 3 is inserted into the second portion 11 of the connector 4. For example, the first end 9a of the second pipe 3 is butted against the internal shoulder 14 of the second portion 11 of the connector 4.

[0096] The first and second portions 10, 11 of connector 4 are connected together.

[0097] Thanks to the connector 4 according to the invention, in particular thanks to its bimetallic nature, it is now possible to connect the connector 4 in a simple and reliable way to both the first pipe 2 and the second pipe 3. Indeed, the first portion 10 of the connector 4 has a metallic material identical or similar to the metallic material of the corrugated conduit 6 and the second portion 11 of the connector 4 has a metallic material identical or similar to the metallic material of the second pipe 3.

[0098] Thanks to this configuration, it is possible to overcome the drawbacks associated with assembling parts made of different materials and thus to connect each of these sections 10, 11 to each of the pipes 2, 3 by a conventional weld. The mechanical strength of the connector 4, and therefore of the pipe 1, is significantly improved.

[0099] The connector 4 according to the invention can then withstand internal pressures of up to 170 bar and temperatures of up to 180°C. It also has a burst resistance of 340 bar.

[0100] In addition, the first and second portions 10, 11 can be linked together simply by suitable methods.

[0101] Several embodiments of connector 4 will now be described.

[0102] According to a first embodiment illustrated in [Fig. 1], the first and second portions 10, 11 of the connector 4 are connected to each other by an annular SI weld. In particular, the second end 12b of the first portion 10 is connected by the SI weld to the first end 13a of the second portion 11. According to this embodiment, the second end 12b of the first portion 10 has an external diameter identical to the external diameter of the first end 13a of the second portion 11.

[0103] The SI weld is preferably a diffusion weld. The diffusion weld is, for example, produced by an explosion welding process or a hot co-rolling process.

[0104] According to a second embodiment illustrated in [Fig.2], the first and second portions 10, 11 of the connector 4 are connected together by an annular S2 weld.

[0105] The S2 weld is, for example, a friction weld.

[0106] In particular, the second end 12b of the first portion 10 can be connected by weld S2 to an external annular shoulder 15 of the second portion 11. The external annular shoulder 15 is located between the first end 13a and the second end 13b of the second portion 11 of the connector 4. According to this method of In a preferred realization, the external diameter of the external shoulder 15 is equal to the external diameter of the second end 12b of the first portion 10.

[0107] Advantageously, according to this second embodiment, the first end 13a of the second portion 11 is inserted into the first portion 10 of the connector 4. Preferably, the external diameter of the second end 12b of the first portion 10 is greater than the external diameter of the first end 12a of the first portion 10.

[0108] According to a third embodiment illustrated in [Fig.3], the first and second portions 10, 11 of the connector 4 are connected together by screwing and optionally by welding.

[0109] According to this third embodiment, the first and second portions 10, 11 are welded together. The connector 4 thus comprises an annular weld S3 formed between the first and second portions 10, 11.

[0110] According to this third embodiment, the first portion 10 of the connector 4 preferably comprises an external thread 16. It thus comprises external helical ribs. These are formed on an external surface of the first portion 10. The external diameter of the external thread 16 is preferably equal to the external diameter of the weld S3.

[0111] According to this third embodiment, the connector 4 further comprises a nut 17 mounted coaxially around the first and second portions 10, 11. The nut 17 allows the first and second portions 10, 11 to be joined together.

[0112] The nut 17 is annular and centered on the longitudinal axis X. It includes an internal thread 18 which cooperates with the external thread 16 of the first portion 10.

[0113] According to a fourth embodiment illustrated in [Fig.4], the first and second portions 10, 11 are joined together by shrink fitting.

[0114] According to this embodiment, the first portion 10 comprises external ribs 19. The external ribs 19 are formed on the external surface of the first portion 10. The external ribs 19 are, for example, helical.

[0115] According to this fourth embodiment, the first portion 10 of the connector 4 is inserted into the second portion 11 of the connector 4. The external ribs 19 thus cooperate with an internal surface of the second portion 11.

[0116] According to this fourth embodiment, advantageously, the second end 12b of the first portion 10 of the connector 4 is abutted against the shoulder intemel4 of the second portion 11.

[0117] A method for manufacturing the conduit 1 according to the invention will now be described with reference to [Fig.5].

[0118] The manufacturing process comprises the following steps:

[0119] (a) provide the first and second portions 10, 11 of connector 4,

[0120] (b) weld the first portion 10 to the corrugated conduit 6,

[0121] (c) weld the second portion 11 to the second pipe 3.

[0122] Steps (b) and (c) can be carried out by a laser welding or brazing process.

[0123] According to a first embodiment, the process may include the following step (a') carried out between steps (a) and (b):

[0124] (a') weld the first and second portions 10, 11 together.

[0125] At step (a'), the welding can be carried out by an explosion welding process or a hot co-rolling process or a friction welding process.

[0126] According to one embodiment, after the steps (b) and (c) of welding the first and second portions 10, 11 respectively to the first and second pipes 2, 3, the process may include a step (d) of assembling the first and second portions 10, 11 together.

[0127] According to one example, the assembly of the first and second portions 10, 11 can be carried out by screwing. According to this example, the nut 17 is mounted around the first and second portions 10, 11.

[0128] According to another example, the assembly of the first and second portions 10, 11 is carried out by shrink fitting. According to this example, the process does not include step (a').

Claims

Demands

1. Pipe (1) for an air conditioning circuit, in particular for a motor vehicle, comprising: - a first pipe (2) having a longitudinal axis (X) and comprising a corrugated conduit (6) comprising a first metallic material and an external sheath (7, 8) arranged coaxially around the corrugated conduit (6), - a second pipe (3) comprising a second metallic material different from the first metallic material, and - a metallic connector (4) connecting the second pipe (3) to the first pipe (2), characterized in that the connector (4) comprises a first tubular portion (10) comprising a material identical or similar to the first material and connected by welding to the corrugated conduit (6), and a second tubular portion (11) comprising a material identical or similar to the second material and connected by welding to the second pipe (3).

2. Conducted according to the preceding claim, characterized in that the first material comprises stainless steel.

3. Conducted according to any one of the preceding claims, characterized in that the second material is aluminum-based.

4. Conduit according to any one of the preceding claims, characterized in that the first portion (10) is connected to a longitudinal end (5a) of the corrugated conduit (6).

5. Conduit according to the preceding claim, characterized in that the first portion (10) has a first longitudinal end (12a) connected to the longitudinal end (5a) of the corrugated conduit (6).

6. Conducted according to any one of the preceding claims, characterized in that the first and second portions (10, 11) are connected to each other by welding or shrink fitting or screwing.

7. Conduit according to any one of the preceding claims, characterized in that the second pipe (3) has a longitudinal end (9a) located inside the second portion (11).

8. A method for manufacturing a pipe according to any one of the preceding claims, characterized in that the method comprises the following chronological steps: (a) supplying the first and second portions (10, 11), (b) weld the first portion (10) to the corrugated conduit (6), and (c) weld the second portion (11) to the second pipe (3).

9. A method according to the preceding claim, characterized in that between step (a) and (b), the method comprises the following step (a'): (a2) welding the first and second portions (10, 11) together.

10. A method according to claims 8 or 9, characterized in that after step (c), the method comprises the following step (d): (d) assembling the first and second portions (10, 11) together by shrink fitting or by screwing.

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