Heat insulation tube for vehicle refrigerant and manufacturing method for the same

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 thermal insulation tube for a vehicle refrigerant that is mounted on a vehicle and has a flow path for a vehicle refrigerant, a method for manufacturing the thermal insulation tube for a vehicle refrigerant, and a thermal insulation tube for a vehicle refrigerant obtained by the manufacturing method. [Background technology]

[0002] Among the on-board devices mounted on a vehicle, for example, an electric motor and a vehicle drive battery, are difficult to fully utilize when they are excessively hot or cold. A typical vehicle is equipped with a heat exchanger to keep such on-board devices at an appropriate temperature. A vehicle refrigerant flows through the heat exchanger, and the heat exchanger exchanges heat with the on-board devices via the vehicle refrigerant. The heat exchanger is connected to a tank for the vehicle refrigerant, an infusion pump, etc., via a thermal insulation tube for the vehicle refrigerant. The thermal insulation tube for the vehicle refrigerant can be said to have a flow path for the vehicle refrigerant that leads 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 keep the vehicle refrigerant that exchanges heat with the vehicle-mounted device within a predetermined temperature range. In order to keep the vehicle refrigerant within a predetermined temperature range, it is considered effective to use a vehicle refrigerant insulated tube that has thermal insulation properties imparted to the vehicle refrigerant tube through which the vehicle refrigerant flows.

[0004] One method for imparting heat insulating properties to a vehicle refrigerant tube to produce a vehicle refrigerant insulated tube is to select a heat insulating material as the material for the vehicle refrigerant insulated tube.

[0005] Patent Document 1 introduces a pipe for circulating high-temperature chemical liquid in a semiconductor manufacturing device. Patent Document 1 describes that the temperature of the chemical liquid is maintained by forming the pipe from a porous tube.

[0006] Patent Document 1 introduces, as a specific example of the above-mentioned porous tube, one having a porous portion made of polytetrafluoroethylene (PTFE) and an acid-base indicator supported on the porous portion. For reference, when an acidic or basic chemical solution flowing through a porous tube leaks, the chemical solution reacts with an acid-base indicator to produce a color. Therefore, the porous tube has the advantage of exhibiting heat insulating properties and making it easy to detect the location of the chemical solution leaking from the porous tube.

[0007] It is believed that if a vehicle refrigerant tube is formed using the above-mentioned porous portion, a thermally insulated vehicle refrigerant tube having thermal insulation properties can be obtained. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] JP 2022-143892 A Summary of the Invention [Problem to be solved by the invention]

[0009] As described above, it is believed that if a vehicle refrigerant tube is formed using the porous portion introduced in Patent Document 1, a vehicle refrigerant heat-insulating tube with heat insulating properties can be obtained.

[0010] Incidentally, since vehicle refrigerant tubes are connected to mating members such as the above-mentioned heat exchangers, they are required to have high strength for connection to the mating members in addition to the above-mentioned heat insulating performance. However, since the porous portion made of PTFE does not have a high rigidity or strength, it may be difficult to maintain its shape, and therefore the heat-insulated vehicle refrigerant tube made of the porous portion may have poor connection strength to a mating member.

[0011] Furthermore, the vehicle refrigerant heat insulating tube may need to be formed into a bent shape according to the arrangement of the vehicle mounted device that is the subject of heat exchange, the heat exchanger, other vehicle mounted devices, etc. However, the vehicle refrigerant heat insulating tube formed of a porous portion may not be able to maintain its shape during bending because of its poor rigidity and strength.

[0012] In addition, because a cold or hot refrigerant flows through the inside of the thermally insulated tube for vehicle refrigerants, the thermally insulated tube for vehicle refrigerants is also subjected to heat, which may cause the thermally insulated tube for vehicle refrigerants to deform or even soften, which may result in the connection between the thermally insulated tube for vehicle refrigerants and the mating member being released or the bent shape being difficult to maintain.

[0013] For this reason, there is a demand for a thermally insulated tube for vehicle refrigerants that is provided with thermal insulation properties and is capable of maintaining its shape during manufacture and use.

[0014] The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a thermally insulated tube for a vehicle refrigerant that is imparted with thermal insulation performance and is capable of maintaining its shape during manufacture and use. [Means for solving the problem]

[0015] One aspect of the insulated tube for vehicle refrigerant of the present invention that solves the above problems is to (1) A tube having a flow path for a vehicle coolant, A flow path forming layer that defines the flow path therein, and a heat insulating layer that covers the flow path forming layer from a radially outer side, The thermal insulation tube for vehicle refrigerant, wherein the flow passage forming layer has a porosity of less than 20%, and the thermal insulation layer has a porosity of 20% or more and less than 80%.

[0016] Another aspect of the insulated tube for vehicle refrigerant of the present invention that solves the above problems is: (2) A tube having a flow path for a vehicle coolant, A flow path forming layer that defines the flow path therein, and a heat insulating layer that covers the flow path forming layer from a radially outer side, The Young's modulus of the flow passage forming layer is 1000 MPa or more and 4000 MPa or less, and the Young's modulus of the insulating layer is less than 1000 MPa.

[0017] One aspect of the method for producing a thermal insulation tube for a vehicle refrigerant of the present invention that solves the above problems is to (3) A method for manufacturing a tube having a flow path for a vehicle refrigerant, the tube having a flow path forming layer that defines the flow path inside the tube, and a heat insulating layer that covers the flow path forming layer from a radially outer side, the method comprising the steps of: The method for manufacturing a thermal insulation tube for a vehicle refrigerant includes an extrusion molding process in which a flow path forming material, which is a material of the flow path forming layer, and a thermal insulation material, which is a material of the thermal insulation layer, are used to extrude the flow path forming layer, which has a porosity of less than 20%, and the thermal insulation layer, which has a porosity of 20% or more and less than 80%.

[0018] Another aspect of the method for producing a thermal insulation tube for a vehicle refrigerant according to the present invention that solves the above problems is to (4) A method for manufacturing a tube having a flow path for a vehicle refrigerant, the tube having a flow path forming layer that defines the flow path inside the tube, and a heat insulating layer that covers the flow path forming layer from a radially outer side, the method comprising the steps of: The method for manufacturing a thermally insulated tube for a vehicle refrigerant includes an extrusion molding process in which a flow path forming material, which is a material for the flow path forming layer, and a thermal insulation material, which is a material for the thermal insulation layer, are used to extrude the flow path forming layer having a Young's modulus of 1000 MPa or more and 4000 MPa or less, and the thermal insulation layer having a Young's modulus of less than 1000 MPa.

[0019] Another aspect of the insulated tube for vehicle refrigerant of the present invention that solves the above problems is: (5) The heat-insulating tube for vehicle refrigerant is extrusion-molded by the manufacturing method described above in (3).

[0020] Another aspect of the insulated tube for vehicle refrigerant of the present invention that solves the above problems is: (6) The heat-insulating tube for vehicle refrigerant is extrusion-molded by the manufacturing method described above in (4). Effect of the Invention

[0021] The insulated tube for vehicle refrigerant of the present invention is a thermally insulated tube for vehicle refrigerant that is imparted with thermal insulation performance and is capable of maintaining its shape during manufacture and use. Also, according to the manufacturing method of the insulated tube for vehicle refrigerant of the present invention, it is possible to provide a thermally insulated tube for vehicle refrigerant that is imparted with thermal insulation performance and is capable of maintaining its shape during manufacture and use. [Brief description of the drawings]

[0022] [Figure 1] FIG. 2 is an explanatory diagram for explaining a schematic appearance of the heat insulating tube for a vehicle according to the first embodiment. [Diagram 2] FIG. 2 is an explanatory view for typically explaining a radial cross section of the thermal insulation tube for a vehicle according to the first embodiment. [Diagram 3] FIG. 2 is an explanatory view for typically explaining an axial cross section of the heat insulating tube for a vehicle according to the first embodiment. [Figure 4] FIG. 11 is an explanatory view for typically explaining a radial cross section of a thermal insulation tube for a vehicle according to a second embodiment. [Diagram 5] FIG. 11 is an explanatory view for typically explaining an axial cross section of a thermal insulation tube for a vehicle according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] The heat-insulated tube for use as a vehicle refrigerant and the method for producing the same according to the present invention will be described below with reference to specific examples.

[0024] Hereinafter, unless otherwise specified, the insulated tube for a vehicle refrigerant of the present invention having the above-mentioned aspect (1) may be referred to as the insulated tube for a vehicle refrigerant of the first aspect. Furthermore, unless otherwise specified, the insulated tube for a vehicle refrigerant of the present invention having the above-mentioned aspect (2) may be referred to as the insulated tube for a vehicle refrigerant of the second aspect. Furthermore, the insulated tube for a vehicle refrigerant of the first aspect and the insulated tube for a vehicle refrigerant of the second aspect may be collectively referred to as the insulated tube for a vehicle refrigerant of the present invention. Unless otherwise specified, the above-mentioned embodiment (3) of the method for producing a thermally insulated tube for a vehicle refrigerant of the present invention may be referred to as the third embodiment of the method for producing a thermally insulated tube for a vehicle refrigerant of the present invention. Unless otherwise specified, the above-mentioned embodiment (4) of the method for producing a thermally insulated tube for a vehicle refrigerant of the present invention may be referred to as the fourth embodiment of the method for producing a thermally insulated tube for a vehicle refrigerant of the present invention. Furthermore, the third embodiment of the method for producing and the fourth embodiment of the method for producing may be collectively referred to as the method for producing of the present invention.

[0025] Unless otherwise specified, the numerical range "x to y" described in this specification includes the lower limit x and the upper limit y. The numerical range can be formed by arbitrarily combining these upper and lower limit values, as well as the numerical values ​​listed in the embodiments. Furthermore, the upper and lower limit values ​​can be arbitrarily selected from within the numerical range.

[0026] The insulated tube for vehicle refrigerant of the present invention is a tube having a flow path for the vehicle refrigerant. It can also be said that the insulated tube for vehicle refrigerant of the present invention has the flow path therein.

[0027] The refrigerant flowing through the flow path is a fluid that flows through the flow path of the vehicle refrigerant insulated tube and can exchange heat with the target vehicle-mounted device, and may be either liquid or gas.

[0028] A specific example of the refrigerant is a long-life coolant (LLC), which is water to which various additives such as preservatives, lubricants, and rust inhibitors have been added, but is not limited to this. The refrigerant may be referred to as a heat exchange medium, a heat medium, or a heat transfer medium.

[0029] The insulated tube for vehicle refrigerant of the present invention has a flow passage forming layer and a heat insulating layer. The flow passage forming layer is a part that defines a flow passage inside and may be called a layer adjacent to the flow passage. On the other hand, the heat insulating layer is a part that covers the flow passage forming layer from the radial outside.

[0030] In the thermally insulated tube for vehicle refrigerant of the present invention, the flow passage forming layer is a portion that defines the flow passage and also plays a role as a connecting portion that is connected to a mating member such as a heat exchanger, and the insulating layer is a portion that plays a role of exhibiting thermal insulation performance.

[0031] In the first embodiment of the insulated tube for use with a vehicle refrigerant, the flow passage forming layer has a porosity of less than 20%, and the insulating layer has a porosity of 20% or more and less than 80%.

[0032] According to the first aspect of the insulated tube for vehicle refrigerant, the porosity of the flow passage forming layer is set to less than 20%, so that the strength and rigidity of the flow passage forming layer can be increased, and the shape can be easily maintained during manufacturing and use. As a result, the insulated tube for vehicle refrigerant of the first aspect can favorably 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 thermally insulated tube for use with a vehicle refrigerant, the Young's modulus of the flow passage forming layer is 1000 MPa or more and 4000 MPa or less, and the Young's modulus of the insulating layer is less than 1000 MPa.

[0034] In the second embodiment of the insulated vehicle refrigerant tube, a material having a higher Young's modulus than the insulating layer, in other words, a material having high rigidity and being less likely to deform, is selected for the flow passage forming layer.

[0035] Specifically, in the second embodiment of the insulated tube for vehicle refrigerants, the Young's modulus of the flow passage forming layer is specified to be 1000 MPa or more and 4000 MPa or less. Such a flow passage forming layer is sufficiently resistant to deformation so as to be able to maintain its shape, and is capable of elastic deformation to be able to connect to a mating member. This allows the second embodiment of the insulated tube for vehicle refrigerants to also favorably maintain its shape during bending and use, and improves the connection strength to the mating member.

[0036] The manufacturing method of the present invention is a method for manufacturing a tube having the above-mentioned flow passage forming layer and heat insulating layer. In the manufacturing method of the present invention, a heat insulating tube for vehicle refrigerant is extrusion molded. More specifically, the manufacturing method of the present invention has an extrusion molding step of extruding the flow passage forming layer and the heat insulating layer using a flow passage forming material which is a material for the flow passage forming layer and a heat insulating material which is a material for the heat insulating layer.

[0037] The above-mentioned vehicle refrigerant insulated tube of the present invention has a flow path for a vehicle refrigerant, and includes a flow path forming layer that defines the flow path inside, and a heat insulating layer that covers the flow path forming layer from the radial outside. Such a vehicle refrigerant insulated tube can also be manufactured by, for example, wrapping and bonding the heat insulating layer around the radial outside of a flow path forming layer that has been prepared in advance.

[0038] However, the wrap-and-bond type vehicle refrigerant insulation tube obtained by wrapping and bonding the insulation layer around the radially outer side of the flow passage forming layer prepared in advance has a large outer shape and is bulky. In many cases, vehicle refrigerant insulation tubes mounted on vehicles are required to be compact, and the above-mentioned wrap-and-bond type vehicle refrigerant insulation tube may not be able to meet this requirement.

[0039] In addition, in the above-mentioned wrapping-bonding type vehicle refrigerant insulation tube, depending on the shape, material combination, etc., the flow path 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 flow passage forming layer and the heat insulating layer will be partially or entirely peeled off.

[0040] In the manufacturing method of the present invention, a thermally insulated tube for vehicle refrigerant is manufactured by extrusion molding. More specifically, as described above, the manufacturing method of the present invention includes an extrusion molding step of extruding the flow path forming layer and the insulating layer using a flow path forming material which is the material of the flow path forming layer and an insulating material which is the material of the insulating layer.

[0041] In the insulated tube for vehicle refrigerant manufactured by the extrusion molding method, i.e., in the insulated tube for vehicle refrigerant obtained by the manufacturing method of the present invention, the flow path forming layer and the insulating layer are fused and firmly bonded, so that peeling between the flow path forming layer and the insulating layer is sufficiently suppressed.

[0042] According to the manufacturing method of the present invention having the above-mentioned extrusion molding step, the thermally insulated tube for vehicle refrigerants or its precursor in which the flow passage forming layer and the insulating layer are fused together can be obtained in a single step, that is, the extrusion molding step. In other words, according to the manufacturing method of the present invention, it is possible to easily manufacture the thermally insulated tube for vehicle refrigerants in which the flow passage forming layer and the insulating layer are firmly bonded together.

[0043] Furthermore, extrusion molding makes it possible to form a compact insulation layer without waste, compared with the above-mentioned wrapping-bonding type method for producing a thermal insulation tube for vehicle refrigerants, that is, a method for wrapping and bonding a thermal insulation layer around the radially outer side of a flow passage forming layer prepared in advance. Therefore, the thermal insulation tube for vehicle refrigerants obtained by the manufacturing method of the present invention has the advantage of being compact, compared with the above-mentioned wrapping-bonding type thermal insulation tube for vehicle refrigerants.

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

[0045] According to the manufacturing method of the third aspect, it is possible to easily manufacture the insulated tube for use with a vehicle refrigerant of the first aspect.

[0046] Moreover, the insulated tube for vehicle refrigerants obtained by the manufacturing method of the third aspect, i.e., the insulated tube for vehicle refrigerants of the above-mentioned fifth aspect, is compact and, like the insulated tube for vehicle refrigerants of the above-mentioned first aspect, can favorably maintain its shape during bending and use, and also has improved connection strength to a mating member.

[0047] In the manufacturing method of the fourth aspect of the present invention, a flow path 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 the manufacturing method of the fourth aspect, it is possible to easily manufacture the insulated tube for use with a vehicle refrigerant of the second aspect described above.

[0049] The insulated tube for vehicle refrigerants obtained by the manufacturing method of the fourth aspect, i.e., the insulated tube for vehicle refrigerants of the sixth aspect described above, is compact and, like the insulated tube for vehicle refrigerants of the second aspect described above, can favorably maintain its shape during bending and use, and also has improved connection strength to a mating member.

[0050] Hereinafter, each component of the insulated tube for vehicle refrigerant use and the method for producing the same of the present invention will be described.

[0051] The insulated tube for use with a vehicle refrigerant of the present invention has a flow passage forming layer and a heat insulating layer.

[0052] The flow path forming layer has a shape having a flow path therein, i.e., a cylindrical shape. The flow path forming layer is a part of the vehicle refrigerant insulating tube of the present invention that can define and form a flow path and that elastically deforms to an extent that it can be connected to a mating member. The part of the mating member that is connected to the flow path forming layer has a flow path through which the refrigerant flows. When the flow path forming layer and the mating member are connected, the flow path of the mating member is connected to the flow path of the flow path forming layer.

[0053] Specifically, as a method for connecting the flow path forming layer and the mating member, it is preferable to adopt a method in which an end portion of the mating member is inserted into the flow path of the flow path forming layer to connect the flow path of the flow path forming layer with the flow path of the mating member, or a method in which an end portion of the flow path forming layer is inserted into the flow path of the mating member to connect the flow path of the flow path forming layer with the flow path of the mating member.

[0054] The flow path forming layer may be elastically deformable or may not be elastically deformable, but in order to maintain the connection between the flow path forming layer and the mating member in an optimal state, it is better for the flow path forming layer to be deformable to a certain extent.

[0055] Therefore, although it is possible to select a material that does not elastically deform, such as metal or ceramics, as the material for the flow path forming layer, it is preferable to select a material that can elastically deform, such as resin, rubber, or elastomer.

[0056] Here, the insulated tube for vehicle refrigerant of the present invention is preferably lightweight for ease of installation in a vehicle. From this viewpoint, it can be said that it is preferable to use various resins, rubbers, or elastomers alone or in combination as the material for the flow passage forming layer.

[0057] As the material for the flow path forming layer, it is also preferable to use a base material made of one or more selected from various resins, rubbers, and elastomers to which a filler such as metal or glass is added. In this case, it is possible to impart various functionalities derived from the filler to the flow path forming layer.

[0058] Specific examples of materials suitable for the flow path forming layer include polypropylene (PP), polyphenylene sulfide (PPS), and polyamide (PA). As described above, these materials may be used alone or in combination. Alternatively, at least one of these materials may be used in combination with other materials.

[0059] It is preferable that the flow passage forming layer has a certain degree of high rigidity, and as described above, in the thermally insulated tube for use with a vehicle refrigerant of the second embodiment, the Young's modulus of the flow passage forming layer is 1000 MPa or more and 4000 MPa or less.

[0060] The flow passage forming layer having a Young's modulus within the above range is not easily deformed to an extent that it can maintain its shape, and is elastically deformable to an extent that it can be connected to a mating member. Therefore, in the first embodiment of the thermally insulated vehicle refrigerant tube, the Young's modulus of the flow passage forming layer is preferably 1000 MPa or more and 4000 MPa or less.

[0061] In order to impart to the flow passage forming layer the performance of being able to withstand use as a flow passage for a vehicle refrigerant and to exhibit a certain degree of rigidity, it is preferable to reduce the porosity of the flow passage forming layer.

[0062] In the first embodiment of the thermally insulated tube for use with a vehicle refrigerant, the porosity of the flow passage forming layer is specified to be less than 20%. In the second embodiment of the insulated tube for vehicle refrigerant, for the same reasons as above, it is preferable to reduce the porosity of the flow path forming layer. Specifically, it is preferable that the porosity of the flow path forming layer is less than 25%, less than 20%, or less than 15%. There is no particular lower limit for the porosity, and the porosity of the flow passage forming layer may be 0%.

[0063] In this specification, the porosity can be expressed as a percentage using the true density and apparent density, i.e., based on the following formula [1]. The apparent density can be measured according to the submerged weighing method specified in JIS K 0061. On the other hand, the true density can be measured according to the pycnometer method using a Gay-Lussac pycnometer, the pycnometer method using a graduated pycnometer, or the pycnometer method using an Ostwald pycnometer, all of which are specified in JIS K 0061. Porosity (%) = 100 - {100 x (apparent density / true density)} ... (1)

[0064] When the flow path forming layer has a porosity of more than 0%, that is, when the flow path forming layer is a porous body having pores, the flow path forming layer may be an open-cell type porous body in which a plurality of pores are connected to each other, or a closed-cell type porous body in which each pore is independent of each other. In some cases, the pores may contain a gas, liquid, or solid different from the main material that defines the pores.

[0065] When the flow path forming layer is a porous body, the average pore diameter of the flow path forming layer is preferably within a range of 10 μm to 600 μm. As a method for measuring the average pore diameter, for example, the following method can be selected.

[0066] First, a cross section of the flow path forming layer is taken at an arbitrary position. Then, an arbitrary 5 mm x 5 mm area is set on the cross section. The maximum diameter of all pores in the area is measured with the naked eye or under a microscope. The maximum diameter of a pore here refers to the maximum value of the distance between two parallel tangents to the pore. The average value of the maximum diameters of the pores in the above area is calculated, and this can be used as the average pore diameter.

[0067] In addition, in order to maintain the shape of the thermally insulated vehicle refrigerant tube during use, it is preferable to select a material having a relatively small linear expansion coefficient as the material for the flow passage layer. A flow passage layer having a small linear expansion coefficient is less likely to deform due to temperature changes.

[0068] The linear expansion coefficient of the material of the flow path forming layer is specifically 5 to 11 × 10 -5 ( / °C).

[0069] The heat insulating layer is a layer that covers the flow passage forming layer from the radially outer side, and is the part that provides heat insulation in the heat insulating tube for vehicle refrigerant of the present invention.

[0070] By forming the insulating layer from a porous body having fine pores, it is possible to impart excellent heat insulation to the insulating layer. In the first embodiment of the thermal insulation tube for vehicle refrigerant, the porosity of the insulating layer is specified to be 20% or more and less than 80%. For the same reasons as above, the insulating layer in the vehicle refrigerant insulating tube of the second embodiment is also preferably a porous body, 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 the first embodiment of the insulated tube for use with a vehicle refrigerant, the Young's modulus of the insulating layer is specified to be less than 1000 MPa. Here, unlike the flow passage forming layer, the heat insulating layer is not required to function as a connection part to the mating member. Therefore, the Young's modulus of the heat insulating layer may be significantly lower than that of the flow passage forming layer. From this viewpoint, the range of the Young's modulus of the heat insulating layer can be exemplified as 0.5 MPa or more and 50 MPa or less, 0.5 MPa or more and 10 MPa or less, and 0.5 MPa or more and 5 MPa or less.

[0072] The heat insulating layer may completely cover the entire passage forming layer, or may cover only a part of the passage forming layer. For example, in the heat insulating tube for vehicle refrigerant of the present invention, one end or both ends of the passage forming layer in the axial direction may be exposed without being covered by the heat insulating layer.

[0073] As described above, the heat insulating layer may cover the entire flow passage forming layer or may cover only a part of it, but it is more preferable that the heat insulating layer covers most of the surface of the flow passage forming layer.

[0074] Specifically, when the surface area of ​​the flow path forming layer is taken as 100%, the heat insulating layer preferably covers 60% or more of it, more preferably covers 70% or more, and particularly preferably covers 80% or more. Note that the surface area of ​​the flow path forming layer here means the apparent surface area calculated on the assumption that the flow path forming layer has no pores.

[0075] The material of the insulating layer should have insulating properties. In other words, it is preferable to select a material with low thermal conductivity as the material of the insulating layer. Specifically, it is preferable that the thermal conductivity of the material of the insulating layer is 5W / (m·°C) or less, 3(m·°C) or less, or 1(m·°C) or less. As the material for the heat insulating layer, it is particularly preferable to select resin, rubber, elastomer, etc.

[0076] Specific examples of the material of the heat insulating layer include olefin elastomer (TPO), styrene thermoplastic elastomer (TPS), PP, PPS, and PA, and the heat insulating layer is preferably a foam using these materials. These materials may be used alone or in combination. Furthermore, at least one of these materials may be used in combination with other materials.

[0077] When the heat insulating layer is a porous body, the heat insulating layer may be an open-cell type porous body or a closed-cell type porous body. In some cases, the pores of the heat insulating layer may contain a gas, liquid, or solid different from the main material that defines the pores.

[0078] When the heat insulating layer is a porous body, the average pore diameter of the heat insulating layer is preferably within the range of 10 μm to 600 μm, similar to the average pore diameter of the flow passage forming layer.

[0079] When the insulation layer is a porous body, particularly when the insulation layer is a foam such as foamed resin, foamed rubber, foamed elastomer, etc., a layer with a low porosity called a skin layer may be formed on the surface of the insulation layer. The skin layer is a layer formed when the insulation 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 a layer having a lower porosity than the other parts of the insulating layer as described above, but can be distinguished from the flow passage layer in that it is very thin.

[0081] Specifically, the thickness of the skin layer can be said to be 1 mm or less. On the other hand, the thickness of the heat insulating layer is greater than that of the flow passage forming layer, and is preferably 1.5 times or more the thickness of the flow passage forming layer, whereas the thickness of the protective layer described below is smaller than that of the flow passage forming layer, and is preferably 0.8 times or less, 0.7 times or less, or 0.5 times or less the thickness of the flow passage forming layer.

[0082] The insulated tube for vehicle refrigerant of the present invention may have a two-layer structure consisting of a flow passage forming layer and a heat insulating layer, but may also have a multi-layer structure of three or more layers including a protective layer in addition to the flow passage forming layer and the heat insulating layer. The protective layer is a layer that covers the heat insulating layer from the radially outer side, and may be a single layer or a multi-layer consisting of two or more layers.

[0083] The heat insulating layer in the heat insulating tube for vehicle refrigerant use of the present invention is a layer having a larger porosity or a smaller Young's modulus than the flow passage forming layer, and can be said to be a layer more fragile than the flow passage forming layer. In the present invention, by providing a protective layer on the outer surface of such a heat insulating layer, the heat insulating layer and, in turn, the entire heat insulating tube for vehicle refrigerant can be protected.

[0084] The protective layer is preferably at least one of a layer having a strength higher than that of the insulating layer, a layer having better weather resistance than that of the insulating layer, and a layer having better heat resistance than that of the insulating layer.

[0085] The protective layer may be any layer capable of reinforcing the heat insulating layer, and there are no particular limitations on its material or structure, but it is preferable that the porosity of the protective layer is lower than that of the heat insulating layer. Specifically, it is preferable that the porosity of the protective layer is less than 20%.

[0086] The protective layer may cover the entire surface of the insulating layer from the outside, or may cover only a part of the surface of the insulating layer from the outside. In order to reliably protect the insulating layer with the protective layer, it is more preferable that the protective layer covers a large part of the surface of the insulating layer.

[0087] Specifically, when the surface area of ​​the insulating layer is taken as 100%, the protective layer preferably covers 60% or more of it, more preferably covers 70% or more, and particularly preferably covers 80% or more. Note that the surface area of ​​the insulating layer here means the apparent surface area calculated under the assumption that the insulating layer has no pores.

[0088] The material of the protective layer may be, for example, at least one selected from PP, PPS, and PA, as in the case of the flow path forming layer. Furthermore, at least one of these materials may be used in combination with other materials. It is preferable that the material of the protective layer is different from the material of the heat insulating layer.

[0089] The heat-insulated tube for use as a vehicle refrigerant and the method for producing the same according to the present invention will be described below with reference to specific examples.

[0090] Example 1 The thermally insulated tube for vehicle refrigerant of Example 1 is the thermally insulated tube for vehicle refrigerant of the first embodiment and is also the thermally insulated tube for vehicle refrigerant of the second embodiment. The manufacturing method of Example 1 is the manufacturing method of the third embodiment and is also the manufacturing method of the fourth embodiment. Therefore, the thermally insulated tube for vehicle refrigerant of Example 1 can be said to be the thermally insulated tube for vehicle refrigerant of the fifth embodiment and is also the thermally insulated tube for vehicle refrigerant of the sixth embodiment.

[0091] Fig. 1 is an explanatory diagram for typically explaining the appearance of the thermal insulation tube for a vehicle according to the first embodiment. Fig. 2 is an explanatory diagram for typically explaining a radial cross section of the thermal insulation tube for a vehicle according to the first embodiment. Fig. 3 is an explanatory diagram for typically explaining an axial cross section of the thermal insulation tube for a vehicle according to the first embodiment.

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

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

[0094] As shown in FIG. 2 and FIG. 3, the vehicle refrigerant-use heat-insulating tube 1 of the first embodiment has a two-layer structure having a flow passage forming layer 2 and a heat insulating layer 3.

[0095] The flow path forming layer 2 is made of PP and has a substantially cylindrical shape. The inside of the substantially cylindrical flow path forming layer 2 is hollow, and the inside functions as a flow path 4 for the vehicle refrigerant. In other words, the flow path forming layer 2 can be said to define and form the flow path 4 for the vehicle refrigerant.

[0096] The heat insulating layer 3 is made of expanded TPO, and has a generally cylindrical shape that covers the entire flow passage forming layer 2 from the outside in the radial direction.

[0097] In the vehicle refrigerant-use thermal insulation tube 1 of Example 1, the porosity of the flow passage 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 flow passage forming layer 2 was about 1350 MPa, while the Young's modulus of the heat insulating layer 3 was significantly lower than 1000 MPa.

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

[0100] The vehicle refrigerant heat-insulating tube 1 of Example 1 uses a porous body with a porosity of about 50% as the heat-insulating layer 3. This provides the vehicle refrigerant heat-insulating tube 1 of Example 1 with sufficient heat-insulating performance.

[0101] The vehicle refrigerant insulated tube 1 of Example 1 uses a flow path forming layer 2 having a porosity of less than 20% and a Young's modulus of approximately 1350 MPa. This allows the strength and rigidity of the flow path forming layer 2 to be sufficiently increased in the vehicle refrigerant insulated tube 1 of Example 1. This allows the vehicle refrigerant insulated tube 1 of Example 1 to stably maintain its shape during bending and use. In addition, the connection strength of the vehicle refrigerant insulated tube 1 of Example 1 to a mating member is also sufficiently increased.

[0102] A method for manufacturing the vehicle refrigerant-use heat-insulated tube 1 of the first embodiment will be described below. The manufacturing method of the vehicle refrigerant heat-insulated tube 1 of the first embodiment 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, a flow path forming material, which is the material for the flow path forming layer 2, and an insulating material, which is the material for the insulating layer 3, were separately placed in a feeder of the extrusion molding machine (not shown), and passed through a molding die of the extrusion molding machine to extrude a straight cylindrical body having the flow path forming layer 2 and the insulating layer 3. The cylindrical body obtained in the above extrusion molding step was heated and bent to obtain the vehicle refrigerant insulating tube 1 of Example 1 bent into a substantially L-shape.

[0104] According to the manufacturing method of the insulated tube for vehicle refrigerant 1 of Example 1, the flow path forming layer 2 and the insulating layer 3 are integrally molded by an extrusion molding process, whereby the insulated tube for vehicle refrigerant 1 of Example 1 having a compact insulating layer 3 with no waste is obtained, unlike the above-mentioned wrapped-and-bonded type insulated tube for vehicle refrigerant.

[0105] According to the manufacturing method of the vehicle refrigerant insulated tube 1 of Example 1, the flow passage forming layer 2 and the insulating layer 3 are simultaneously molded by an extrusion molding process, so that the flow passage forming layer 2 and the insulating layer 3 are fused and firmly bonded to each other. This makes it possible to reliably suppress peeling between the flow passage forming layer 2 and the insulating layer 3, and to obtain the vehicle refrigerant insulated tube 1 of Example 1 that is endowed with high strength and excellent durability.

[0106] Furthermore, the process of molding and fusing the flow passage forming layer 2 and the insulating layer 3 can be completed in a single process, that is, an extrusion molding process. As a result, according to the manufacturing method of the thermally insulated tube for vehicle refrigerant 1 of the first embodiment, it is possible to easily manufacture the thermally insulated tube for vehicle refrigerant 1 of the first embodiment.

[0107] Example 2 The thermally insulated tube for use with a vehicle refrigerant of the second embodiment is generally the same as the thermally insulated tube for use with a vehicle refrigerant of the first embodiment, except that it has a protective layer.

[0108] Therefore, the thermally insulated tube for a vehicle refrigerant of Example 2 is the thermally insulated tube for a vehicle refrigerant of the first embodiment and is also the thermally insulated tube for a vehicle refrigerant of the second embodiment. Moreover, the manufacturing method of Example 2 is the manufacturing method of the third embodiment and is also the manufacturing method of the fourth embodiment. Therefore, the thermally insulated tube for a vehicle refrigerant of Example 2 can also be said to be the thermally insulated tube for a vehicle refrigerant of the fifth embodiment and is also the thermally insulated tube for a vehicle refrigerant of the sixth embodiment.

[0109] Fig. 4 is an explanatory view for typically explaining a radial cross section of the thermal insulation tube for a vehicle according to the second embodiment. Fig. 5 is an explanatory view for typically explaining an axial cross section of the thermal insulation tube for a vehicle according to the second embodiment. The following describes the thermally insulated tube for use with a vehicle refrigerant according to the first embodiment and the method for producing the same, focusing on the differences from the thermally insulated tube for use with a vehicle refrigerant according to the first embodiment.

[0110] 4 and 5, the vehicle refrigerant insulated tube 1 of Example 2 has a protective layer 5 that covers the entire surface of the insulating layer 3 from the outside in the radial direction. 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 path forming layer 2.

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

[0112] According to the insulated tube 1 for use with a vehicle refrigerant of Example 2, by covering the outer side of the insulating layer 3 with the protective layer 5, it is possible to impart excellent heat resistance to the insulated tube 1 for use with a vehicle refrigerant, and ultimately to improve the durability of the insulated tube 1 for use with a vehicle refrigerant.

[0113] The thermally insulated tube for use with a vehicle refrigerant of the second embodiment is provided with sufficient thermal insulation performance by the insulating layer 3, like the thermally insulated tube for use with a vehicle refrigerant of the first embodiment.

[0114] In the thermally insulated vehicle refrigerant tube 1 of Example 2, the strength and rigidity of the flow passage forming layer 2 are sufficiently increased, similar to the thermally insulated vehicle refrigerant tube 1 of Example 1, and the shape is stably maintained during bending and use. In addition, the thermally insulated vehicle refrigerant tube 1 of Example 2 has a sufficiently increased connection strength to a mating member, similar to the thermally insulated vehicle refrigerant tube 1 of Example 1.

[0115] The method for producing the thermally insulated tube for vehicle refrigerant 1 of the second embodiment includes the same extrusion molding process as the method for producing the thermally insulated tube for vehicle refrigerant 1 of the first embodiment.

[0116] More specifically, in the manufacturing method of the vehicle refrigerant insulation tube of Example 2, in the extrusion molding process, a flow path forming material which is a material for the flow path forming layer 2, an insulating material which is a material for the insulating layer 3, and a protective material which is a material for the protective layer 5 are separately placed in a feeder of an extrusion molding machine not shown in the figure, and a straight tubular body having the flow path forming layer 2, the insulating layer 3, and the protective layer 5 is extruded through a molding die of the extrusion molding machine. The cylindrical body obtained in the above extrusion molding step was heated and bent to obtain a substantially L-shaped insulated vehicle refrigerant tube 1 of Example 2.

[0117] According to the manufacturing method of the thermally insulated tube for vehicle refrigerant 1 of Example 2, the flow path forming layer 2, the insulating layer 3 and the protective layer 5 are integrally molded by an extrusion molding process, whereby the thermally insulated tube for vehicle refrigerant 1 of Example 2 having the insulating layer 3 and the protective layer 5 with no waste and compactness can be obtained, unlike the above-mentioned wrapped-bonded type thermally insulated tube for vehicle refrigerant.

[0118] Furthermore, according to the manufacturing method of the vehicle refrigerant insulating tube 1 of Example 2, the flow path forming layer 2, the insulating layer 3 and the protective layer 5 are simultaneously molded by the extrusion molding process, so that the flow path forming layer 2 and the insulating layer 3 are fused and firmly bonded to each other, and the insulating layer 3 and the protective layer 5 are fused and firmly bonded to each other.

[0119] Thus, according to the manufacturing method of the insulated tube for vehicle refrigerant 1 of Example 2, peeling between the flow path forming layer 2 and the insulating layer 3 can be reliably suppressed, and peeling between the insulating layer 3 and the protective layer 5 can also be reliably suppressed. As a result, the insulated tube for vehicle refrigerant 1 of Example 2 can be obtained, which has high strength and excellent durability.

[0120] Although the present invention has been described above, the present invention is not limited to the above-described embodiments, and it is possible to implement the present invention by appropriately extracting and combining elements described in the embodiments, and to make various modifications without departing from the spirit of the present invention. Furthermore, the specification of the present invention discloses not only the citation relationships of each claim at the time of the initial application, but also a technical idea that appropriately combines the matters described in each claim. [Explanation of symbols]

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

Claims

1. A tube having a flow path for a vehicle coolant, A flow path forming layer that defines the flow path therein, and a heat insulating layer that covers the flow path forming layer from a radially outer side, The thermal insulation tube for vehicle refrigerant, wherein the flow passage forming layer has a porosity of less than 20%, and the thermal insulation layer has a porosity of 20% or more and less than 80%.

2. A tube having a flow path for a vehicle coolant, A flow path forming layer that defines the flow path therein, and a heat insulating layer that covers the flow path forming layer from a radially outer side, A thermal insulation tube for vehicle refrigerants, wherein the flow passage forming layer has a Young's modulus of 1000 MPa or more and 4000 MPa or less, and the insulating layer has a Young's modulus of less than 1000 MPa.

3. 2. The thermal insulation tube for vehicle refrigerant according to claim 1, wherein the flow passage forming layer has a Young's modulus of 1000 MPa or more and 4000 MPa or less.

4. The insulated tube for use as a vehicle refrigerant according to claim 2 , wherein the porosity of the insulating layer is 20% or more and less than 80%.

5. Further, a protective layer is provided to cover the heat insulating layer from the radially outer side, 3. The thermal insulation tube for vehicle refrigerant according to claim 1, wherein the protective layer has a porosity of less than 20%.

6. A method for manufacturing a tube having a flow path for a vehicle refrigerant, the tube having a flow path forming layer that defines the flow path inside the tube, and a heat insulating layer that covers the flow path forming layer from a radially outer side, the method comprising the steps of: A method for manufacturing a thermal insulation tube for a vehicle refrigerant, comprising an extrusion molding process of extruding the flow path forming layer having a porosity of less than 20% and the insulation layer having a porosity of 20% or more and less than 80% using a flow path forming material that is a material of the flow path forming layer and an insulation material that is a material of the insulation layer.

7. A method for manufacturing a tube having a flow path for a vehicle refrigerant, the tube having a flow path forming layer that defines the flow path inside the tube, and a heat insulating layer that covers the flow path forming layer from a radially outer side, the method comprising the steps of: A method for manufacturing an insulated tube for a vehicle refrigerant, comprising an extrusion molding process for extruding the flow path forming layer having a Young's modulus of 1000 MPa or more and 4000 MPa or less and the insulating layer having a Young's modulus of less than 1000 MPa using a flow path forming material that is a material of the flow path forming layer and an insulating material that is a material of the insulating layer.

8. A heat-insulating tube for vehicle refrigerant, extruded by the method according to claim 6.

9. A heat-insulating tube for vehicle refrigerant, extruded by the method according to claim 7.

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