Insulated tubes for vehicle refrigerants

Abstract

To provide a heat insulation tube for a vehicle refrigerant to which heat insulation performance is applied and that can maintain the shape during manufacturing and use.SOLUTION: A heat insulation tube 1 for a vehicle refrigerant is a tube having a flow passage 4 for the vehicle refrigerant and includes a flow passage formation layer 2 that defines and forms the flow passage 4 therein and a heat insulation layer 3 that covers the flow passage formation layer 2 from the radial outer side. A void ratio of the flow passage formation layer 2 is less than 20%, and a void ratio of the heat insulation layer 3 is 20% or more and less than 80%.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a heat-insulating tube for a vehicle refrigerant having a flow path for the vehicle refrigerant mounted on a vehicle, a method for manufacturing the heat-insulating tube for the vehicle refrigerant, and a heat-insulating tube for the vehicle refrigerant obtained by the manufacturing method.

Background Art

[0002] Among vehicle-mounted devices mounted on a vehicle, for example, an electric motor, a vehicle drive battery, etc. are difficult to exhibit sufficient capacity when they are excessively hot or excessively cold. A general vehicle is equipped with a heat exchanger for keeping this type of vehicle-mounted device at an appropriate temperature. A vehicle refrigerant flows through the heat exchanger, and the heat exchanger exchanges heat with the vehicle-mounted device via the vehicle refrigerant. The heat exchanger is connected to a tank for the vehicle refrigerant, an infusion pump, etc. via a heat-insulating tube for the vehicle refrigerant. It can be said that the heat-insulating tube for the vehicle refrigerant has a flow path for the vehicle refrigerant leading to the heat exchanger, the tank, the infusion pump, etc.

[0003] In order to keep the vehicle-mounted device at an appropriate temperature, it is considered effective to maintain the vehicle refrigerant that exchanges heat with the vehicle-mounted device within a predetermined temperature range. In order to maintain the vehicle refrigerant within a predetermined temperature range, it is considered effective to use a heat-insulating tube for the vehicle refrigerant having heat-insulating performance provided to the tube for the vehicle refrigerant through which the vehicle refrigerant flows.

[0004] As one method for imparting heat-insulating performance to a tube for the vehicle refrigerant to obtain a heat-insulating tube for the vehicle refrigerant, it is conceivable to select a heat-insulating material as the material of the heat-insulating tube for the vehicle refrigerant.

[0005] Patent Document 1 introduces a pipe for circulating a high-temperature chemical solution in a semiconductor manufacturing apparatus. Patent Document 1 describes that the temperature of the chemical solution is maintained because the pipe is formed of a porous tube.

[0006] Patent Document 1 introduces a specific example of the above-mentioned porous tube, which has a porous portion made of polytetrafluoroethylene (PTFE) and an acid-base indicator supported on the porous portion. For reference, if an acidic or basic chemical solution leaks through a porous tube, it reacts with an acid-base indicator, causing a color change. Therefore, the porous tube offers the advantage of providing thermal insulation while also allowing for easy detection of leaks within the tube.

[0007] It is believed that by forming a vehicle refrigerant tube using the porous portion described above, a vehicle refrigerant insulated tube with improved heat insulation properties can be obtained. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2022-143892 [Overview of the project] [Problems that the invention aims to solve]

[0009] As described above, it is believed that by forming a vehicle refrigerant tube using the porous portion described in Patent Document 1, a vehicle refrigerant insulated tube with heat insulation properties can be obtained.

[0010] Incidentally, vehicle refrigerant tubes are required to be connected to mating components such as the heat exchangers mentioned above, and therefore, in addition to the aforementioned thermal insulation performance, they must also be connected to the mating components with high strength. However, the porous portion made of PTFE, as described above, does not have very high rigidity or strength, which can make it difficult to maintain its shape. For this reason, a vehicle refrigerant insulation tube formed with this porous portion may have inferior connection strength to the mating component.

[0011] Furthermore, insulated tubes for vehicle refrigerants sometimes need to be formed into bent shapes depending on the arrangement of the vehicle-mounted equipment that is the target of heat exchange, such as heat exchangers and other vehicle-mounted equipment. However, insulated tubes for vehicle refrigerants formed from porous material have inferior rigidity and strength, which can prevent them from maintaining their shape during bending.

[0012] Furthermore, because cold or hot refrigerant flows through the insulated tubes for vehicle refrigerants, heat acts on the insulated tubes themselves. This heat may cause the insulated tubes to deform or, in some cases, soften, which could result in the connection between the insulated tubes and the mating components being broken, or making it difficult to maintain the bent shape described above.

[0013] Therefore, there is a need for insulated tubes for vehicle refrigerants that provide thermal insulation and maintain their shape during manufacturing and use.

[0014] This invention has been made in view of the above circumstances, and aims to solve the problem of providing an insulating tube for vehicle refrigerants that is provided with heat insulation performance and can maintain its shape during manufacturing and use. [Means for solving the problem]

[0015] One embodiment of the present invention, which solves the above problems, is a heat insulating tube for vehicle refrigerants. (1) A tube having a flow path for vehicle refrigerant, It comprises a channel-forming layer that partitions and forms the channel internally, and a heat insulating layer that covers the channel-forming layer from the radially outer side, The porosity of the flow channel forming layer is less than 20%, and the porosity of the heat insulating layer is 20% or more and less than 80%, in this heat insulating tube for vehicle refrigerants.

[0016] Another aspect of the present invention, which solves the above problems, is a heat insulating tube for vehicle refrigerants, (2) A tube having a flow path for vehicle refrigerant, It has a flow path forming layer that partitions and forms the flow path inside, and a heat insulating layer that covers the flow path forming layer from the radially outer side. It is a heat insulating tube for vehicle refrigerant, wherein the Young's modulus of the flow path forming layer is 1000 MPa or more and 4000 MPa or less, and the Young's modulus of the heat insulating layer is less than 1000 MPa.

[0017] One aspect of the manufacturing method of the heat insulating tube for vehicle refrigerant of the present invention that solves the above problems is (3) A method for manufacturing a tube having a flow path for vehicle refrigerant, having a flow path forming layer that partitions and forms the flow path inside, and a heat insulating layer that covers the flow path forming layer from the radially outer side, comprising: Using a flow path forming material that is a material of the flow path forming layer and a heat insulating material that is a material of the heat insulating layer, and having an extrusion molding step of extrusion molding the flow path forming layer having a porosity of less than 20% and the heat insulating layer having a porosity of 20% or more and less than 80%. It is a manufacturing method of a heat insulating tube for vehicle refrigerant.

[0018] Another aspect of the manufacturing method of the heat insulating tube for vehicle refrigerant of the present invention that solves the above problems is (4) A method for manufacturing a tube having a flow path for vehicle refrigerant, having a flow path forming layer that partitions and forms the flow path inside, and a heat insulating layer that covers the flow path forming layer from the radially outer side, comprising: Using a flow path forming material that is a material of the flow path forming layer and a heat insulating material that is a material of the heat insulating layer, and having an extrusion molding step of extrusion molding the flow path forming layer having a Young's modulus of 1000 MPa or more and 4000 MPa or less and the heat insulating layer having a Young's modulus of less than 1000 MPa. It is a manufacturing method of a heat insulating tube for vehicle refrigerant.

[0019] Another aspect of the heat insulating tube for vehicle refrigerant of the present invention that solves the above problems is (5) It is a heat insulating tube for vehicle refrigerant extruded by the manufacturing method of (3) above.

[0020] Another aspect of the heat insulating tube for vehicle refrigerant of the present invention that solves the above problems is (6) This is an insulated tube for vehicle refrigerants, extruded by the manufacturing method described in (4) above. [Effects of the Invention]

[0021] The present invention provides a vehicle refrigerant insulation tube that is insulated and maintains its shape during manufacturing and use. Furthermore, the manufacturing method of the vehicle refrigerant insulation tube of the present invention makes it possible to provide a vehicle refrigerant insulation tube that is insulated and maintains its shape during manufacturing and use. [Brief explanation of the drawing]

[0022] [Figure 1] This is an explanatory diagram illustrating the appearance of the vehicle insulation tube of Example 1. [Figure 2] This is an explanatory diagram illustrating the radial cross-section of the vehicle insulation tube of Example 1. [Figure 3] This is an explanatory diagram illustrating a schematic cross-section of the axial direction of the vehicle insulation tube of Example 1. [Figure 4] This is an explanatory diagram illustrating the radial cross-section of the vehicle insulation tube of Example 2. [Figure 5] This is an explanatory diagram illustrating a schematic cross-section of the axial direction of the vehicle insulation tube of Example 2. [Modes for carrying out the invention]

[0023] The present invention, including a heat-insulating tube for vehicle refrigerants and a method for manufacturing the same, will be described below with specific examples.

[0024] In the following, unless otherwise specified, the vehicle refrigerant insulation tube of the present invention that conforms to the embodiment described in (1) above may be referred to as the vehicle refrigerant insulation tube of the first embodiment. Also, unless otherwise specified, the vehicle refrigerant insulation tube of the present invention that conforms to the embodiment described in (2) above may be referred to as the vehicle refrigerant insulation tube of the second embodiment. Furthermore, the vehicle refrigerant insulation tube of the first embodiment and the vehicle refrigerant insulation tube of the second embodiment may be collectively referred to as the vehicle refrigerant insulation tube of the present invention. Furthermore, unless otherwise specified, the method of manufacturing an insulating tube for vehicle refrigerants according to the present invention, as described in (3) above, may be referred to as the manufacturing method of the third embodiment. Unless otherwise specified, the method of manufacturing an insulating tube for vehicle refrigerants according to the present invention, as described in (4) above, may be referred to as the manufacturing method of the fourth embodiment. In addition, the manufacturing methods of the third embodiment and the manufacturing methods of the fourth embodiment may be collectively referred to as the manufacturing method of the present invention.

[0025] Unless otherwise specified, the numerical range "x~y" described herein includes a lower limit x and an upper limit y. Furthermore, a numerical range can be constructed by arbitrarily combining these upper and lower limits, as well as the numerical values ​​listed in the embodiments. Additionally, any numerical values ​​arbitrarily selected from within the numerical range can be used as the upper and lower limits.

[0026] The vehicle refrigerant insulation tube of the present invention is a tube having a flow path for vehicle refrigerant. The vehicle refrigerant insulation tube of the present invention can also be described as having the said flow path inside.

[0027] The refrigerant flowing through the flow path is a fluid that flows through the flow path of an insulated tube for vehicle refrigerants, and only needs to be capable of heat exchange with the vehicle-mounted equipment in question; it may be a liquid or a gas.

[0028] Specific examples of refrigerants include, but are not limited to, long-life coolants (LLC), which are water to which various additives such as preservatives, lubricants, and rust inhibitors have been added. The refrigerant in question may also be referred to as a heat exchange medium, heat transfer medium, or heat transfer fluid, etc.

[0029] The present invention provides an insulated tube for vehicle refrigerants, comprising a flow channel forming layer and an insulating layer. The flow channel forming layer is the portion that divides and forms a flow channel within it, and can also be described as a layer adjacent to the flow channel. The insulating layer, on the other hand, is the portion that covers the flow channel forming layer from the radially outer side.

[0030] In the vehicle refrigerant insulation tube of the present invention, the flow path forming layer is a part that divides and forms a flow path and also serves as a connecting part that connects to a mating component such as a heat exchanger. The insulation layer is a part that provides insulation performance.

[0031] In the first embodiment of the vehicle refrigerant insulation tube, the porosity of the flow channel forming layer is less than 20%, and the porosity of the insulation layer is 20% or more and less than 80%.

[0032] According to the first embodiment of the vehicle refrigerant insulation tube, by setting the porosity of the flow channel forming layer to less than 20%, the strength and rigidity of the flow channel forming layer can be increased, and consequently, it becomes easier to maintain its shape during manufacturing and use. As a result, the vehicle refrigerant insulation tube of the first embodiment can suitably maintain its shape even during bending and use, and the connection strength to the mating member is also improved.

[0033] On the other hand, in the second embodiment of the insulated tube for vehicle refrigerants, the Young's modulus of the flow channel forming layer is 1000 MPa or more and 4000 MPa or less, and the Young's modulus of the insulation layer is less than 1000 MPa.

[0034] In the second embodiment of the insulated tube for vehicle refrigerants, a material with a higher Young's modulus than the insulating layer, in other words, a material with high rigidity and resistance to deformation, is selected as the flow path forming layer.

[0035] Specifically, in the second embodiment of the vehicle refrigerant insulation tube, the Young's modulus of the flow channel forming layer is specified to be between 1000 MPa and 4000 MPa. Such a flow channel forming layer is sufficiently resistant to deformation to the extent that it can maintain its shape, and yet elastically deformable to the extent that it can connect with the mating member. As a result, the vehicle refrigerant insulation tube of the second embodiment can also suitably maintain its shape during bending and use, and the connection strength to the mating member is also improved.

[0036] The present invention relates to a method for manufacturing a tube having the above-described channel-forming layer and heat insulating layer. In the present invention, a heat insulating tube for vehicle refrigerants is extruded. More specifically, the present invention relates to an extrusion molding step in which a channel-forming layer and a heat insulating layer are extruded using a channel-forming material, which is the material for the channel-forming layer, and a heat insulating material, which is the material for the heat insulating layer.

[0037] The above-described insulated tube for vehicle refrigerants of the present invention has a flow path for vehicle refrigerant, and comprises a flow path forming layer that partitions the flow path internally, and an insulating layer that covers the flow path forming layer from the radially outer side. Such an insulated tube for vehicle refrigerants can also be manufactured, for example, by wrapping and bonding the insulating layer around the radially outer side of a pre-prepared flow path forming layer.

[0038] However, the wrap-and-bond type of vehicle refrigerant insulation tube, obtained by wrapping and bonding an insulating layer around the radially outer surface of a pre-prepared flow channel forming layer, has a large and bulky outer shape. Vehicle refrigerant insulation tubes installed in vehicles often require compactness, and the above-mentioned wrap-and-bond type vehicle refrigerant insulation tube may not be suitable in such cases.

[0039] Furthermore, in the aforementioned wrap-and-bond type vehicle refrigerant insulation tubes, depending on the shape and combination of materials, the flow channel forming layer and the insulation layer may not be bonded with sufficient strength, making it difficult to maintain the shape of the vehicle refrigerant insulation tube. In this case, for example, it is expected that the channel-forming layer and the insulating layer may partially or completely separate.

[0040] The manufacturing method of the present invention involves manufacturing an insulating tube for vehicle refrigerants using an extrusion molding method. More specifically, as described above, the manufacturing method of the present invention includes an extrusion molding step of extruding a channel forming layer and a heat insulating layer using a channel forming material which is the material for the channel forming layer and a heat insulating layer which is the material for the heat insulating layer.

[0041] In vehicle refrigerant insulation tubes manufactured by extrusion molding, that is, vehicle refrigerant insulation tubes obtained by the manufacturing method of the present invention, the flow channel forming layer and the insulation layer are fused together and firmly joined, so delamination between the flow channel forming layer and the insulation layer is sufficiently suppressed.

[0042] Furthermore, according to the manufacturing method of the present invention having the extrusion molding step described above, a vehicle refrigerant insulation tube or its precursor, in which a channel forming layer and an insulation layer are fused together, can be obtained in a single step of extrusion molding. In other words, according to the manufacturing method of the present invention, it is possible to easily manufacture a vehicle refrigerant insulation tube in which a channel forming layer and an insulation layer are firmly joined together.

[0043] Furthermore, extrusion molding allows for the formation of a more compact and efficient insulation layer compared to the aforementioned wrap-and-bond type method for manufacturing vehicle refrigerant insulation tubes, that is, the method of wrapping and bonding the insulation layer to the radially outer side of a pre-prepared flow channel forming layer. Therefore, the vehicle refrigerant insulation tube obtained by the manufacturing method of the present invention also has the advantage of being more compact than the aforementioned wrap-and-bond type vehicle refrigerant insulation tube.

[0044] By the way, in the manufacturing method of the third aspect of the present invention, a flow channel forming layer having a void ratio of less than 20% and a heat insulating layer having a void ratio of 20% or more and less than 80% are formed in the extrusion molding step.

[0045] According to this third embodiment of the manufacturing method, it is possible to easily manufacture the insulated tube for vehicle refrigerant according to the first embodiment described above.

[0046] Furthermore, the vehicle refrigerant insulation tube obtained by the manufacturing method of the third embodiment, i.e., the vehicle refrigerant insulation tube of the fifth embodiment described above, is compact and, like the vehicle refrigerant insulation tube of the first embodiment described above, can suitably maintain its shape during bending and use, and the connection strength to the mating member is also improved.

[0047] In the manufacturing method of the fourth aspect of the present invention, a flow channel forming layer having a Young's modulus of 1000 MPa or more and 4000 MPa or less, and a heat insulating layer having a Young's modulus of less than 1000 MPa are formed in the extrusion molding step.

[0048] According to this fourth embodiment of the manufacturing method, it is possible to easily manufacture the vehicle refrigerant insulation tube described in the second embodiment above.

[0049] Furthermore, the vehicle refrigerant insulation tube obtained by the manufacturing method of the fourth embodiment, i.e., the vehicle refrigerant insulation tube of the sixth embodiment described above, is compact and, like the vehicle refrigerant insulation tube of the second embodiment described above, can suitably maintain its shape during bending and use, and the connection strength to the mating member is also improved.

[0050] The present invention's heat-insulating tube for vehicle refrigerants and its manufacturing method will be described below for each component.

[0051] The heat-insulating tube for vehicle refrigerants of the present invention has a flow channel forming layer and a heat-insulating layer.

[0052] The channel-forming layer has a shape that includes a channel inside, i.e., it is cylindrical. Furthermore, this channel-forming layer is the portion of the vehicle refrigerant insulation tube of the present invention that can partition and form a channel and is elastically deformable to the extent that it can connect to a mating member. The portion of the mating member that is connected to the channel-forming layer has a channel through which the refrigerant flows. When the channel-forming layer and the mating member are connected, the channel of the mating member communicates with the channel of the channel-forming layer.

[0053] Specifically, as a method for connecting the channel forming layer and the mating member, it is preferable to employ either a method in which the end of the mating member is inserted into the channel of the channel forming layer to connect the channel of the channel forming layer and the channel of the mating member, or a method in which the end of the channel forming layer is inserted into the channel of the mating member to connect the channel of the channel forming layer and the channel of the mating member.

[0054] The channel forming layer may be elastically deformable or not elastically deformable, but in order to maintain a suitable connection between the channel forming layer and the mating member, it is preferable for the channel forming layer to be deformable to some extent.

[0055] Therefore, while materials that do not elastically deform, such as metals or ceramics, can be selected as the material for the channel-forming layer, it is preferable to select elastically deformable materials such as resins, rubbers, or elastomers.

[0056] In this context, the heat-insulating tube for vehicle refrigerants of the present invention is preferably lightweight for installation in a vehicle. From this viewpoint, it is preferable to use various resins, rubbers, or elastomers individually or in combination as the material for the flow channel forming layer.

[0057] Furthermore, it is also preferable to use a base material consisting of one or more resins, rubbers, or elastomers selected from various types, to which fillers such as metals or glass are added. In this case, it becomes possible to impart various functionalities derived from the fillers to the channel-forming layer.

[0058] Specific materials suitable for the channel-forming layer include polypropylene (PP), polyphenylene sulfide (PPS), and polyamide (PA). As previously mentioned, these materials may be used individually or in combination. Alternatively, at least one of these materials may be used in combination with other materials.

[0059] The flow channel forming layer is preferably made of a relatively rigid material, and as previously described, in the second embodiment of the insulated tube for vehicle refrigerants, the Young's modulus of the flow channel forming layer is 1000 MPa or more and 4000 MPa or less.

[0060] A flow channel forming layer having a Young's modulus within the above range is sufficiently resistant to deformation to the extent that it can maintain its shape, and is elastically deformable to the extent that it can connect with the mating member. Therefore, in the heat insulating tube for vehicle refrigerants of the first embodiment, it is preferable that the Young's modulus of the flow channel forming layer be between 1000 MPa and 4000 MPa.

[0061] Furthermore, in order to impart to the flow channel forming layer the ability to withstand use as a flow channel for vehicle refrigerant and to exhibit a certain degree of rigidity, it is preferable to reduce the porosity of the flow channel forming layer.

[0062] In the first embodiment of the insulated tube for vehicle refrigerants, the porosity of the flow channel forming layer is specified to be less than 20%. In the second embodiment of the vehicle refrigerant insulation tube, for the same reasons as above, it is preferable to lower the porosity of the flow channel forming layer, and specifically, it is preferable that the porosity of the flow channel forming layer be less than 25%, less than 20%, or less than 15%. Furthermore, there is no specific lower limit for this porosity, and the porosity of the channel-forming layer may be 0%.

[0063] In this specification, porosity can be expressed as a percentage using, for example, true density and apparent density, i.e., based on the following formula [1]. For the measurement of apparent density, the liquid weighing method specified in JIS K 0061 should be followed. On the other hand, for the measurement of true density, the specific gravity bottle method using a Gay-Lussac specific gravity bottle, the specific gravity bottle method using a graduated pycnometer, or the specific gravity bottle method using an Ostwald pycnometer, as specified in JIS K 0061, should be followed. Porosity (%) = 100 - {100 × (Apparent density / True density)} ... [1]

[0064] If the channel-forming layer has a porosity of more than 0%, that is, if the channel-forming layer is a porous material having pores, the channel-forming layer may be a connected-cell type porous material in which multiple pores are interconnected, or it may be a closed-cell type porous material in which each pore is independent of the others. In some cases, the pores may contain gases, liquids, or solids different from the main material that partitions and forms the pores.

[0065] When the channel-forming layer is a porous material, the average pore diameter of the channel-forming layer is preferably in the range of 10 μm to 600 μm. For example, the following methods can be selected for measuring the average pore diameter.

[0066] First, take a cross-section of the channel-forming layer at an arbitrary location. Then, define an arbitrary 5mm x 5mm region within that cross-section. Measure the maximum diameter of all pores within this region either visually or under a microscope. Here, the maximum diameter of a pore refers to the maximum distance between two parallel tangents for that pore. Calculate the average of the maximum diameters of the pores within the above region and use this as the average pore diameter.

[0067] Furthermore, considering the need to maintain the shape of the vehicle refrigerant insulation tube during use, it is preferable to select a material with a relatively small coefficient of linear expansion for the channel forming layer. A channel forming layer with a small coefficient of linear expansion exhibits less deformation due to temperature changes.

[0068] The coefficient of thermal expansion of the channel-forming layer material is, specifically, 5 to 11 × 10⁻⁶. -5 It is preferable that the temperature be within the range of ( / °C).

[0069] The insulating layer is a layer that covers the flow channel forming layer from the radially outer side, and is the part of the insulating tube for vehicle refrigerants of the present invention that is responsible for insulating properties.

[0070] By constructing an insulating layer with a porous material having fine pores, it is possible to impart excellent insulating properties to the insulating layer. In the insulating tube for vehicle refrigerants of the first embodiment, the porosity of the insulating layer is specified to be 20% or more and less than 80%. The insulating layer in the insulating tube for vehicle refrigerants of the second embodiment is also preferably porous for the same reasons as described above, and its porosity is preferably 15% or more and less than 90%, 20% or more and less than 80%, or 25% or more and less than 70%.

[0071] In addition, in the first embodiment of the vehicle refrigerant insulation tube, the Young's modulus of the insulation layer is specified to be less than 1000 MPa. Here, unlike the channel forming layer, the thermal insulation layer is not required to function as a connection point to the mating member. Therefore, the Young's modulus of the thermal insulation layer may be significantly lower than that of the channel forming layer. From this perspective, examples of Young's modulus ranges for the thermal insulation layer include 0.5 MPa to 50 MPa, 0.5 MPa to 10 MPa, and 0.5 MPa to 5 MPa.

[0072] The heat insulating layer may completely cover the entire channel forming layer, or it may cover only a part of the channel forming layer. For example, in the heat insulating tube for vehicle refrigerants of the present invention, one or both ends of the channel forming layer in the axial direction may be exposed and not covered by the heat insulating layer.

[0073] As mentioned above, the insulating layer may cover the entire channel-forming layer or only a part of it, but it is more preferable to cover a large portion of the surface of the channel-forming layer.

[0074] Specifically, when the surface area of ​​the channel-forming layer is set to 100%, it is preferable for the insulating layer to cover 60% or more, more preferably 70% or more, and particularly preferable 80% or more. The surface area of ​​the channel-forming layer referred to here means the apparent surface area calculated assuming that the channel-forming layer has no pores.

[0075] The material for the insulation layer should be a material with insulation properties. In other words, it is preferable to select a material with low thermal conductivity for the insulation layer. Specifically, the thermal conductivity of the insulation layer material should preferably be 5 W / (m·°C) or less, 3 (m·°C) or less, or 1 (m·°C) or less. Resin, rubber, elastomer, etc., are particularly suitable materials for the insulation layer.

[0076] Specific examples of materials for the insulation layer include olefin-based elastomers (TPO: Thermoplastic Olefinic Elastomer), styrene-based thermoplastic elastomers (TPS: Thermoplastic Styrenic Elastomer), PP, PPS, and PA. The insulation layer is preferably a foam made from these materials. These materials may be used individually or in combination. Furthermore, at least one of these materials may be used in combination with other materials.

[0077] If the insulation layer is a porous material, it may be a continuous-cell type or a closed-cell type. In some cases, the pores of the insulation layer may contain gases, liquids, or solids different from the main material that partitions the pores.

[0078] When the insulating layer is a porous material, it is preferable that the average pore diameter of the insulating layer be in the range of 10 μm to 600 μm, similar to the average pore diameter of the channel forming layer.

[0079] When the insulating layer is porous, especially when the insulating layer is a foam such as foamed resin, foamed rubber, or foamed elastomer, a layer with a low porosity called a skin layer may form on the surface of the insulating layer. This skin layer is formed when the insulating layer is formed, and is formed when the portion of the molding material injected into the mold that is in contact with the mold surface of the mold is rapidly cooled.

[0080] The skin layer is made of the same material as the insulating layer and is formed integrally with the insulating layer. The skin layer is layered and, as described above, has a lower porosity than other parts of the insulating layer, but it can be distinguished from the channel-forming layer by its extremely thin thickness.

[0081] Specifically, the thickness of the skin layer can be said to be less than 1 mm. In contrast, the thickness of the heat insulating layer is greater than the thickness of the channel forming layer, preferably 1.5 times or more the thickness of the channel forming layer. The thickness of the protective layer, which will be described later, is less than the thickness of the channel forming layer, preferably 0.8 times or less, 0.7 times or less, or 0.5 times or less the thickness of the channel forming layer.

[0082] The heat-insulating tube for vehicle refrigerants of the present invention may have a two-layer structure consisting of a flow channel forming layer and a heat-insulating layer, but it may also have a multilayer structure of three or more layers including a protective layer in addition to the flow channel forming layer and the heat-insulating layer. The protective layer is a layer that covers the insulation layer from the radial outside, and may be a single layer or a multilayer layer of two or more layers.

[0083] The insulating layer in the insulating tube for vehicle refrigerants of the present invention is a layer with a larger porosity or a smaller Young's modulus than the flow channel forming layer, and can be said to be a more fragile layer than the flow channel forming layer. In this invention, by providing a protective layer on the outermost layer of such an insulating layer, the insulating layer can be protected, and consequently, the entire insulating tube for vehicle refrigerants can be protected.

[0084] The protective layer is preferably at least one of the following: a layer with higher strength than the insulation layer, a layer with better weather resistance than the insulation layer, or a layer with better heat resistance than the insulation layer.

[0085] The protective layer can be any material that can reinforce the insulation layer, and there are no particular limitations on its material or structure, however, it is preferable that the porosity of the protective layer be lower than that of the insulation layer. Specifically, it is preferable that the porosity of the protective layer be less than 20%.

[0086] The protective layer may cover the entire surface of the insulation layer from the outside, or it may cover only a portion of the surface of the insulation layer from the outside. To reliably protect the insulation layer with the protective layer, it is more preferable for the protective layer to cover a large portion of the surface of the insulation layer.

[0087] Specifically, when the surface area of ​​the insulation layer is considered to be 100%, it is preferable for the protective layer to cover 60% or more, more preferably 70% or more, and especially preferable 80% or more. Note that the surface area of ​​the insulation layer referred to here means the apparent surface area calculated assuming that the insulation layer has no pores.

[0088] As the material for the protective layer, for example, at least one can be selected from PP, PPS, and PA, similar to the channel forming layer. Furthermore, at least one of these materials may be used in combination with other materials. It is preferable that the material for the protective layer is different from the material for the heat insulating layer.

[0089] The present invention, including a heat-insulating tube for vehicle refrigerants and a method for manufacturing the same, will be described below with specific examples.

[0090] (Example 1) The vehicle refrigerant insulation tube of Example 1 is both a vehicle refrigerant insulation tube of the first embodiment and a vehicle refrigerant insulation tube of the second embodiment. Furthermore, the manufacturing method of Example 1 is both a manufacturing method of the third embodiment and a manufacturing method of the fourth embodiment. Therefore, it can also be said that the vehicle refrigerant insulation tube of Example 1 is both a vehicle refrigerant insulation tube of the fifth embodiment and a vehicle refrigerant insulation tube of the sixth embodiment.

[0091] Figure 1 shows a schematic diagram illustrating the appearance of the vehicle insulation tube of Example 1. Figure 2 shows a schematic diagram illustrating the radial cross-section of the vehicle insulation tube of Example 1. Figure 3 shows a schematic diagram illustrating the axial cross-section of the vehicle insulation tube of Example 1.

[0092] The vehicle refrigerant insulation tube 1 of Example 1 is mounted on a vehicle (not shown) and constitutes a part of the flow path for the vehicle refrigerant. As shown in Figure 1, the vehicle refrigerant insulation tube 1 of Example 1 is substantially cylindrical and bent into a substantially L-shape.

[0093] One axial end 11 of the vehicle refrigerant insulation tube 1 in Example 1 is connected to a mating component, an infusion pump (not shown), via a joint 90 which is an injection molded product. The other end 12 is connected to a mating component, a heat exchanger (not shown).

[0094] As shown in Figures 2 and 3, the vehicle refrigerant insulation tube 1 of Example 1 has a two-layer structure having a flow channel forming layer 2 and an insulation layer 3.

[0095] The flow channel forming layer 2 is made of PP and has a roughly cylindrical shape. The inside of the roughly cylindrical flow channel forming layer 2 is hollow, and this interior functions as a flow channel 4 for the vehicle refrigerant. In other words, it can be said that the flow channel forming layer 2 partitions and forms the flow channel 4 for the vehicle refrigerant.

[0096] The heat insulating layer 3 is made of foamed TPO and has a substantially cylindrical shape that covers the entire channel forming layer 2 from the radial outside.

[0097] In the vehicle refrigerant insulation tube 1 of Example 1, the porosity of the flow channel forming layer 2 was approximately 0%, and the porosity of the insulation layer 3 was approximately 50%. The average pore size of the insulation layer 3 was approximately 300 μm.

[0098] The Young's modulus of the channel-forming layer 2 was approximately 1350 MPa, while the Young's modulus of the insulating layer 3 was significantly below 1000 MPa.

[0099] In the vehicle refrigerant insulation tube 1 of Example 1, the coefficient of linear expansion of the flow channel forming layer 2 is 11 × 10 -5 It was ( / ℃). The thickness of the flow channel forming layer 2 was 1.5 mm, and the thickness of the heat insulating layer 3 was 3 mm. For reference, in the heat insulating tube 1 for vehicle refrigerant of Example 1, a skin layer 30 is formed on the surface of the heat insulating layer 3, i.e., on the surface of the heat insulating tube 1 for vehicle refrigerant. The thickness of this skin layer 30 was slightly less than 1 mm.

[0100] In Example 1, the vehicle refrigerant insulation tube 1 uses a porous material with a void ratio of approximately 50% as the insulation layer 3. This provides the vehicle refrigerant insulation tube 1 of Example 1 with sufficient insulation performance.

[0101] Furthermore, the vehicle refrigerant insulation tube 1 of Example 1 uses a flow channel forming layer 2 with a porosity of less than 20% and a Young's modulus of approximately 1350 MPa. As a result, the strength and rigidity of the flow channel forming layer 2 are sufficiently increased in the vehicle refrigerant insulation tube 1 of Example 1. Consequently, the shape of the vehicle refrigerant insulation tube 1 of Example 1 is stably maintained even during bending and use. In addition, the connection strength of the vehicle refrigerant insulation tube 1 of Example 1 to the mating member is also sufficiently increased.

[0102] The method for manufacturing the vehicle refrigerant insulation tube 1 of Example 1 is described below. The manufacturing method for the vehicle refrigerant insulation tube 1 of Example 1 includes an extrusion molding step based on an extrusion molding method called two-color extrusion molding or co-extrusion molding.

[0103] In this extrusion molding process, the channel forming material, which is the material for the channel forming layer 2, and the heat insulating material, which is the material for the heat insulating layer 3, were separately placed into the feeder of an extrusion molding machine (not shown in the figure), and a straight cylindrical body having the channel forming layer 2 and the heat insulating layer 3 was extruded through the mold of the extrusion molding machine. The cylindrical body obtained in the extrusion molding process described above was heated and bent to obtain the vehicle refrigerant insulation tube 1 of Example 1, which is bent into a roughly L-shape.

[0104] According to the manufacturing method of the vehicle refrigerant insulation tube 1 of Example 1, by integrally forming the flow channel forming layer 2 and the insulation layer 3 by an extrusion molding process, unlike the previously described winding-bonding type vehicle refrigerant insulation tube, the vehicle refrigerant insulation tube 1 of Example 1 is obtained, which has a compact and waste-free insulation layer 3.

[0105] Furthermore, according to the manufacturing method of the vehicle refrigerant insulation tube 1 of Example 1, the flow channel forming layer 2 and the insulation layer 3 are formed simultaneously by an extrusion molding process, causing the flow channel forming layer 2 and the insulation layer 3 to fuse together and be firmly joined. As a result, delamination between the flow channel forming layer 2 and the insulation layer 3 can be reliably suppressed, and the vehicle refrigerant insulation tube 1 of Example 1 is obtained with high strength and excellent durability.

[0106] Furthermore, the process of forming and fusing the flow channel forming layer 2 and the heat insulating layer 3 can be completed in a single step called the extrusion molding process. As a result, the heat insulating tube 1 for vehicle refrigerant of Example 1 can be easily manufactured according to the manufacturing method of Example 1.

[0107] (Example 2) The vehicle refrigerant insulation tube of Example 2 is substantially the same as the vehicle refrigerant insulation tube of Example 1, except that it has a protective layer.

[0108] Therefore, the vehicle refrigerant insulation tube of Example 2 is both a vehicle refrigerant insulation tube of the first embodiment and a vehicle refrigerant insulation tube of the second embodiment. Furthermore, the manufacturing method of Example 2 is both a manufacturing method of the third embodiment and a manufacturing method of the fourth embodiment. Therefore, it can also be said that the vehicle refrigerant insulation tube of Example 2 is both a vehicle refrigerant insulation tube of the fifth embodiment and a vehicle refrigerant insulation tube of the sixth embodiment.

[0109] Figure 4 shows a schematic diagram illustrating the radial cross-section of the vehicle insulation tube of Example 2. Figure 5 shows a schematic diagram illustrating the axial cross-section of the vehicle insulation tube of Example 2. The following describes the vehicle refrigerant insulation tube of Example 1 and its manufacturing method, focusing on the differences from the vehicle refrigerant insulation tube of Example 1.

[0110] As shown in Figures 4 and 5, the vehicle refrigerant insulation tube 1 of Example 2 has a protective layer 5 that covers the entire surface of the insulation layer 3 from the radially outer side. The protective layer 5 is made of foamed PA and has a porosity of about 10%. The thickness of the protective layer 5 is about 1 mm, which is about 0.6 to 0.7 times the thickness of the flow channel forming layer 2.

[0111] The melting point of PA is higher than that of TPO. Therefore, in the vehicle refrigerant insulation tube 1 of Example 2, the protective layer 5 made of foamed PA has better heat resistance than the insulation layer 3 made of foamed TPO.

[0112] According to the vehicle refrigerant insulation tube 1 of Example 2, by covering the outside of the insulation layer 3 with a protective layer 5, the vehicle refrigerant insulation tube 1 can be given excellent heat resistance, and consequently, the durability of the vehicle refrigerant insulation tube 1 can be improved.

[0113] The vehicle refrigerant insulation tube of Example 2 is provided with sufficient insulation performance by the insulation layer 3, similar to the vehicle refrigerant insulation tube 1 of Example 1.

[0114] Furthermore, the vehicle refrigerant insulation tube 1 of Example 2, like the vehicle refrigerant insulation tube 1 of Example 1, has sufficiently increased strength and rigidity of the flow path forming layer 2, and its shape is stably maintained even during bending and use. In addition, the vehicle refrigerant insulation tube 1 of Example 2, like the vehicle refrigerant insulation tube 1 of Example 1, has sufficiently increased connection strength to the mating member.

[0115] The method for manufacturing the vehicle refrigerant insulation tube 1 of Example 2 has the same extrusion molding process as the method for manufacturing the vehicle refrigerant insulation tube 1 of Example 1.

[0116] More specifically, in the manufacturing method for vehicle refrigerant insulation tubes of Example 2, during the extrusion molding process, the channel forming material, which is the material for the channel forming layer 2, the insulation material, which is the material for the insulation layer 3, and the protective material, which is the material for the protective layer 5, were separately placed into the feeder of an extrusion molding machine (not shown), and a straight cylindrical body having the channel forming layer 2, the insulation layer 3, and the protective layer 5 was extruded through the mold of the extrusion molding machine. The cylindrical body obtained in the extrusion molding process described above was heated and bent to obtain the vehicle refrigerant insulation tube 1 of Example 2, which is bent into a roughly L-shape.

[0117] According to the manufacturing method of the vehicle refrigerant insulation tube 1 of Example 2, the flow channel forming layer 2, the insulation layer 3, and the protective layer 5 are integrally formed by an extrusion molding process. This results in a vehicle refrigerant insulation tube 1 of Example 2 having a compact and efficient insulation layer 3 and protective layer 5, unlike the previously described winding-bonding type vehicle refrigerant insulation tube.

[0118] Furthermore, according to the manufacturing method of the vehicle refrigerant insulation tube 1 of Example 2, the flow channel forming layer 2, the insulation layer 3, and the protective layer 5 are simultaneously formed by an extrusion molding process, thereby fusing and firmly joining the flow channel forming layer 2 and the insulation layer 3, and fusing and firmly joining the insulation layer 3 and the protective layer 5.

[0119] As a result, the manufacturing method for the vehicle refrigerant insulation tube 1 of Example 2 can reliably suppress delamination between the flow channel forming layer 2 and the insulation layer 3, and can also reliably suppress delamination between the insulation layer 3 and the protective layer 5. Consequently, the vehicle refrigerant insulation tube 1 of Example 2 is obtained, which is endowed with high strength and excellent durability.

[0120] Although the present invention has been described above, the present invention is not limited to the embodiments described above, and it is possible to implement the invention by appropriately extracting and combining the elements described in the embodiments, and to make various modifications without departing from the spirit of the present invention. Furthermore, the specification of this invention discloses not only the reference relationships of each claim as initially filed, but also a technical concept that appropriately combines the matters described in each claim. [Explanation of Symbols]

[0121] 1: Insulated tube for vehicle refrigerant 2: Channel-forming layer 3: Insulation layer 4: Flow channel 5:Protective layer

Claims

1. A tube having a flow path for vehicle refrigerant, It comprises a channel-forming layer that partitions and forms the channel internally, and a heat insulating layer that covers the channel-forming layer from the radially outer side, An insulating tube for vehicle refrigerants, wherein the porosity of the flow channel forming layer is less than 20%, the porosity of the insulating layer is 20% or more and less than 80%, and the Young's modulus of the flow channel forming layer is 1000 MPa or more and 4000 MPa or less.

2. A tube having a flow path for vehicle refrigerant, It comprises a channel-forming layer that partitions and forms the channel internally, and a heat insulating layer that covers the channel-forming layer from the radially outer side, An insulating tube for vehicle refrigerants, wherein the Young's modulus of the flow channel forming layer is 1000 MPa or more and 4000 MPa or less, the Young's modulus of the insulating layer is less than 1000 MPa, and the porosity of the insulating layer is 20% or more and less than 80%.

3. Furthermore, the thermal insulation layer has a protective layer that covers it from the radially outer side, The insulating tube for vehicle refrigerant according to claim 1 or claim 2, wherein the porosity of the protective layer is less than 20%.

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