Method for manufacturing refrigerant manifold, and refrigerant manifold

Abstract

A method for manufacturing a refrigerant manifold (1) according to an embodiment of the present invention comprises: a step for disposing, in a mold (12), a collapsible core (16) corresponding to a plurality of flow paths (101); a step for pouring a molten metal (14) into the mold (12); a step for solidifying the molten metal (14) to cast an intermediate structure (17); and a step for dissolving and discharging the collapsible core (16) from the intermediate structure (17) to form the plurality of flow paths (101).

Description

Method for manufacturing refrigerant manifold and refrigerant manifold

[0001] This embodiment relates to a method for manufacturing a refrigerant manifold and a refrigerant manifold.

[0002] Conventionally, in a refrigerant system mounted on vehicles such as engine vehicles, hybrid vehicles, and electric vehicles, it is known to use a manifold made of an aluminum alloy instead of piping. By using a refrigerant manifold instead of piping, the entire refrigerant system can be downsized.

[0003] International Publication WO2024 / 024443

[0004] Generally, as a method for manufacturing a refrigerant manifold, a method of forming a refrigerant flow path by aluminum brazing a press part, a rolled part, etc. to a base material is used. However, in order to use this method, it is necessary to use a silicon-free aluminum material as a material to maintain the quality of aluminum brazing. Furthermore, when using a silicon-free aluminum material for the material, the casting property deteriorates, so gravity casting cannot be adopted as a casting method, and it is limited to an expensive method by melt forging. For this reason, the manufacturing cost of the refrigerant manifold becomes high.

[0005] An example of the problem to be solved by the present invention is to provide a method for manufacturing a refrigerant manifold and a refrigerant manifold that can suppress the manufacturing cost.

[0006] The method for manufacturing a refrigerant manifold of the present invention includes a step of disposing collapsible cores corresponding to a plurality of flow paths in a mold, a step of pouring molten metal into the mold, a step of solidifying the molten metal to cast an intermediate structure, and a step of dissolving and discharging the collapsible cores from the intermediate structure to form a plurality of flow paths.

[0007] Further, the refrigerant manifold of the present invention is characterized in that a plurality of flow paths are formed by disposing collapsible cores in a mold, pouring molten metal into the mold, solidifying it to cast an intermediate structure, and dissolving and discharging the collapsible cores from the intermediate structure.

[0008] According to the above embodiment of the present invention, the manufacturing cost of the refrigerant manifold can be reduced.

[0009] Figure 1 shows an example of the external appearance and part of the internal structure of a refrigerant manifold according to the embodiment. Figure 2 is a schematic diagram showing the salt core of the refrigerant manifold according to the embodiment. Figure 3 is a schematic diagram showing a cross-section of the flow path of the refrigerant manifold according to the embodiment. Figure 4 is a schematic diagram showing a cross-section of another flow path of the refrigerant manifold according to the embodiment. Figure 5 is a flowchart showing the steps of the manufacturing method of the refrigerant manifold according to the embodiment. Figure 6 is a side view showing part of the external appearance of the refrigerant manifold according to the embodiment.

[0010] [Embodiment] Hereinafter, the refrigerant manifold 1 according to the embodiment will be described in detail with reference to the attached drawings. The configuration of the embodiment described below, and the operation and results (effects) brought about by said configuration, are merely examples and are not limited to the contents described below. In this specification, ordinal numbers are used only to distinguish parts and components and do not indicate order or priority.

[0011] First, with reference to Figure 1, the outline of the refrigerant manifold 1 according to this embodiment will be described. Figure 1 is a diagram showing an example of the external appearance and part of the internal structure of the refrigerant manifold 1 according to this embodiment. The refrigerant manifold 1 described in this embodiment is an example of a refrigerant manifold used in a refrigerant system installed in electric vehicles such as hybrid vehicles (HV) and electric vehicles (EV). The refrigerant manifold 1 of this embodiment may be used in an internal combustion engine vehicle or in a vehicle equipped with another power source.

[0012] In the following figures, for convenience, three mutually orthogonal directions are defined. The depth direction of the refrigerant manifold 1 is defined as the X-axis direction, the width direction of the refrigerant manifold 1 is defined as the Y-axis direction, and the height direction of the refrigerant manifold 1 is defined as the Z-axis direction. The X-axis direction may also be referred to as the front-to-back direction. The Y-axis direction may also be referred to as the left-to-right direction. The Z-axis direction may also be referred to as the up-and-down direction. Note that the expressions indicating directions such as front-to-back, left-to-right, up-and-down in this embodiment are for convenience only and do not limit the position, orientation, or manner of use of the refrigerant manifold 1.

[0013] As shown in Figure 1, the refrigerant manifold 1 comprises a main body 10 having internally formed, substantially cylindrical flow paths 101a, 101c, 101d, 101e, and 101f. In Figure 1, Figure 1(a) shows the main body 10 viewed from diagonally above, Figure 1(b) shows the main body 10 viewed from below (-Z direction), and Figure 1(c) shows the flow paths 101a, 101c, 101d, 101e, and 101f inside the main body 10. In the following description, the flow paths 101a, 101c, 101d, 101e, and 101f may be collectively referred to as flow path 101.

[0014] The main body 10 is a casting made from an intermediate structure 17 (described later) obtained by pouring molten aluminum material 14 into a mold 12 and allowing it to solidify. In this embodiment, the main body 10 is made by gravity casting. By making the main body 10 by gravity casting, the manufacturing cost of the refrigerant manifold 1 can be reduced compared to high-cost molten metal forging.

[0015] The aluminum material 14 is an aluminum alloy containing silicon, for example, the substance indicated as AC4C in JIS H5202. Generally, aluminum alloys containing silicon have good castability and are therefore suitable for gravity casting. The aluminum material 14 is not limited to aluminum alloys containing silicon; any metal with a relatively low melting point is acceptable. The aluminum material 14 is an example of an aluminum alloy containing molten metal and silicon.

[0016] The flow path 101 is a cylindrical void through which a liquid or gaseous refrigerant (not shown) can flow. The flow path 101 is in communication with a heat exchanger, reservoir tank, etc. (not shown) connected to the outside of the refrigerant manifold 1. The refrigerant flows through the flow path 101 to the heat exchanger, reservoir tank, etc.

[0017] The flow channel 101 is formed, for example, by gravity casting using a salt core 16. More specifically, in the gravity casting manufacturing process of the refrigerant manifold 1, the flow channel 101 is formed in the position corresponding to the flow channel 101 in the mold 12 in advance, molten aluminum material 14 is poured into the mold 12 and then solidified, after which the salt core 16 is melted and discharged to the outside of the mold 12, thereby forming the flow channel 101 at the position corresponding to the salt core 16.

[0018] Here, the salt core 16 will be explained using Figure 2. Figure 2 is a schematic diagram showing the salt core 16 of the refrigerant manifold 1 according to this embodiment. The salt core 16 is formed in a substantially cylindrical shape and is placed inside the mold 12 at a position corresponding to the flow path 101 during the manufacture of the refrigerant manifold 1. Figure 2 shows a part of the salt core 16 placed inside the mold 12 during the manufacture of the refrigerant manifold 1, viewed from the cross-sectional direction of the salt core 16 (flow path 101).

[0019] The salt core 16 is made by solidifying sodium chloride powder, a type of water-soluble substance, in a mold. The salt core 16 is an example of a disintegrating core. By using the salt core 16 as the core, the refrigerant manifold 1 can be manufactured without any foreign matter such as core particles remaining in the main body 10 during manufacturing, thereby improving quality. Note that a sand core may be used instead of the salt core 16.

[0020] The salt core 16 forms multiple flow channels 101 through which the refrigerant flows. More specifically, as shown in Figure 2, the salt core 16 forms multiple flow channels 101 with a substantially circular cross-section in the radial direction.

[0021] Therefore, the cross-sectional area of ​​the flow path 101 is larger than that of the flow path in a two-piece structure made by aluminum brazing (the cross-section is approximately semicircular), and the refrigerant flowing through the flow path 101 experiences reduced pressure loss, improving circulation performance. Consequently, the refrigerant system using the refrigerant manifold 1 can improve the performance of the refrigerant system.

[0022] The salt core 16 has a substantially uniform shape in each of its radial cross-sections, but it may be formed using multiple lumpy objects with different cross-sectional shapes.

[0023] Returning to Figures 1(a), (b), and (c), the main body 10 is provided with multiple openings 101C at each end of the multiple flow paths 101. Each of the multiple openings 101C communicates with the outside of the main body 10. The multiple openings 101C are oriented in either the X-axis direction, the Y-axis direction, or the Z-axis direction. Note that in Figure 1, some of the multiple openings 101C are omitted.

[0024] The main body 10 has an upper surface 102. The upper surface 102 faces in the +Z direction. The upper surface 102 has an uneven shape corresponding to the position of the flow path 101 formed inside the main body 10. Details of this will be described later.

[0025] Next, the details of the flow path 101 will be described with reference to Figures 3 and 4. Figure 3 is a schematic diagram showing a cross-section of the flow path 101 of the refrigerant manifold 1 according to this embodiment. As shown in Figure 3, the radial cross-sections of the multiple flow paths 101 are substantially circular. Furthermore, the radial cross-sectional area of ​​the flow path 101 is larger than that of the flow path 101 when its cross-section is substantially semicircular. As a result, the pressure loss of the refrigerant flowing inside the flow path 101 is suppressed.

[0026] Figure 4 is a schematic diagram showing a cross-section of another flow path 101 of the refrigerant manifold 1 according to this embodiment. As shown in Figure 4, the upper surface 102 of the main body 10 is formed such that the wall thickness in the +Z direction (thickness d1, d2 in Figure 4) is approximately the same for each of the flow paths 101. In other words, the mold 12 has approximately the same wall thickness d1, d2 relative to the upper surface 102 for each of the flow paths 101.

[0027] On the other hand, in a two-piece structure using aluminum brazing, for example, the upper surface of the main body is formed by aluminum brazing press-formed or rolled parts to the base material, resulting in a nearly flat shape without irregularities. Therefore, the refrigerant manifold 1 can suppress variations in wall thickness in the +Z direction of each flow path 101, and can be made lighter compared to a two-piece structure using aluminum brazing.

[0028] [Method for Manufacturing a Refrigerant Manifold] Next, the method for manufacturing the refrigerant manifold 1 will be described with reference to Figure 5. Figure 5 is a flowchart showing the steps for manufacturing the refrigerant manifold 1 according to this embodiment.

[0029] Step S101 in Figure 5 is the process of preparing (creating) the salt core 16 that will form the flow path 101. In step S101, the worker prepares the salt core 16 to form the flow path 101 of the refrigerant manifold 1.

[0030] Next, in step S102, the worker places the salt core 16 inside the mold 12 (first step). Here, placement means fixing the salt core 16 inside the mold 12, so that the molten aluminum material 14 can be poured into the mold 12. The positions where the salt core 16 is placed correspond to the multiple flow paths 101, that is, the positions where the refrigerant manifold 1 with the flow paths 101 formed after subsequent processes is obtained, and in this embodiment, these are the positions shown as flow paths 101a to 101f in Figure 1.

[0031] Then, in step S103, the worker pours the molten aluminum material 14 into the mold 12 in which the salt core 16 is placed. More specifically, the worker pours the molten aluminum alloy containing silicon into the mold 12 in which the salt core 16 is placed (second step).

[0032] Then, in step S104, the worker cools and solidifies the molten aluminum material 14. This casts an intermediate structure 17 in which the salt core 16 and the aluminum material 14 are integrated (third step).

[0033] Finally, in step S105, the worker dissolves the salt core 16 from the intermediate structure 17 and discharges it to the outside of the mold 12, forming multiple channels 101 (fourth step). Here, dissolution refers to dissolving the salt core 16 from the intermediate structure 17 by immersing the intermediate structure 17 in water or the like.

[0034] In this dissolution process, the water-soluble nature of the salt core 16 is utilized, allowing the salt core 16 to be easily dissolved from the intermediate structure 17 in which the salt core 16 and aluminum material 14 are integrated. This process creates a flow path 101 in the location where the salt core 16 was previously positioned before dissolution. Through these steps, a refrigerant manifold 1 is obtained.

[0035] In the refrigerant manifold 1 obtained by the process described above, the mold 12 is a single-piece structure rather than a two-piece structure, thus eliminating the need for brazing. This simplifies the manufacturing process of the refrigerant manifold 1, improving the accuracy of the work performed by the operator. Furthermore, since the heating process due to brazing is eliminated, the thermal impact on the base material can be suppressed. Consequently, the quality of the refrigerant manifold 1 can be improved.

[0036] Furthermore, the refrigerant manifold 1 can be manufactured using a silicon-containing material, which is cheaper than silicon-free material, and can be manufactured by gravity forging, which is less expensive than molten metal forging, without brazing. Therefore, the manufacturing cost of the refrigerant manifold 1 can be reduced.

[0037] [Ratio of proportions] Here, assuming a refrigerant manifold with a two-piece structure constructed by aluminum brazing (hereinafter referred to as a two-piece refrigerant manifold), we will further explain the irregularities of the upper surface 102 of the refrigerant manifold 1 with reference to Figure 6. Figure 6 is a side view showing a part of the external appearance of the refrigerant manifold 1 according to this embodiment. Figure 6 shows the refrigerant manifold 1 of Figures 1(a) and (b) as viewed from the -X direction.

[0038] As shown in Figure 6, the refrigerant manifold 1 has approximately the same thickness in each of the multiple flow paths 101 relative to the upper surface 102 (the surface on the +Z direction side in Figure 6). Therefore, the upper surface 102 of the refrigerant manifold 1 has an uneven shape.

[0039] In contrast, a two-piece refrigerant manifold generally forms the refrigerant flow path by aluminum brazing a roughly flat pressed or rolled part to the base material. Furthermore, the surface to which aluminum brazing is performed in a two-piece refrigerant manifold is roughly flat. For this reason, the depths of the multiple flow paths relative to the aluminum brazing surface (corresponding to the distance in the Z-axis direction from the upper surface 102 in Figure 6) may differ.

[0040] In this case, the wall thickness of the aluminum brazed surface is not uniform in each of the multiple flow paths, resulting in some sections of the flow path having a wall thickness greater than necessary for structural reasons. The more sections with excessive wall thickness, the heavier the two-piece refrigerant manifold becomes.

[0041] In other words, the refrigerant manifold 1 in this embodiment has reduced the amount of material thickness required for its structure, making it lighter than a two-piece refrigerant manifold. By using the lightweight refrigerant manifold 1 in a vehicle's refrigerant system, the vehicle can be made lighter, which in turn can improve the vehicle's power performance, fuel efficiency (electricity consumption), driving range, and other factors.

[0042] As described above, the method for manufacturing the refrigerant manifold 1 of this embodiment comprises the steps of: arranging salt cores 16 corresponding to a plurality of flow paths 101 in a mold 12; pouring molten metal (aluminum material 14) into the mold 12; solidifying the molten metal to cast an intermediate structure 17; and dissolving and discharging the salt cores 16 from the intermediate structure 17 to form a plurality of flow paths 101.

[0043] In the process of manufacturing the refrigerant manifold 1 of the present embodiment, first, the cores 16 corresponding to the plurality of flow paths 101 are arranged in the mold 12. Next, molten metal (aluminum material 14) is poured into the mold 12, and the molten metal is solidified to cast an intermediate structure 17 in which the cores 16 and the metal are integrated. Then, the cores 16 are dissolved from the intermediate structure 17 and discharged to the outside of the mold 12, and the plurality of flow paths 101 are formed.

[0044] According to the above manufacturing method, since the flow path 101 is formed by the cores 16, the refrigerant manifold 1 does not need to have a structure divided into a plurality of parts and can be integrally formed. Since the refrigerant manifold 1 is integrally formed, there is no need to perform aluminum brazing. When aluminum brazing is not performed, there is no need to use an expensive silicon-free material for manufacturing, and an inexpensive silicon-containing material can be used. When a silicon-containing material is used in manufacturing, since the castability of the material is good, there is no need to select expensive melt forging as a manufacturing method, and low-cost gravity forging can be selected. As a result, the manufacturing cost of the refrigerant manifold 1 can be suppressed.

[0045] In the manufacturing method of the refrigerant manifold 1 of the present embodiment, in the step of arranging the cores 16 for forming the plurality of flow paths 101 in the mold 12, the cores 16 form the plurality of flow paths 101 having a substantially circular cross section in the radial direction.

[0046] In the two-piece structure by aluminum brazing, the mold of the refrigerant manifold is made by melt forging in which a press part or a rolled part having a substantially flat plate shape is aluminum brazed to a base material in which a flow path having a substantially semicircular cross section in the radial direction is formed. In this case, since the cross section of the flow path formed in the mold is substantially semicircular, the refrigerant flowing through the flow path has a large pressure loss and the circulation performance deteriorates.

[0047] On the other hand, in the refrigerant manifold 1 of the present embodiment, since the flow path 101 is formed by the cores 16, there is no bonding process of the press part by aluminum brazing during manufacturing and the mold 12 is integrated. In the process of manufacturing the refrigerant manifold 1, the cores 16 form the plurality of flow paths 101 having a substantially circular cross section in the radial direction.

[0048] Therefore, the refrigerant manifold 1 of the present embodiment has a larger cross-sectional area of the flow path 101 and a smaller pressure loss of the refrigerant than, for example, a two-piece structure by aluminum brazing. As a result, the refrigerant manifold 1 can improve the circulation performance of the refrigerant.

[0049] Further, in the manufacturing method of the refrigerant manifold 1 of the present embodiment, the mold 12 has a substantially equal wall thickness with respect to a predetermined surface (upper surface 102) in each of the plurality of flow paths 101.

[0050] In a two-piece structure by aluminum brazing, the depths of the plurality of flow paths in the mold of the refrigerant manifold may be different with respect to the surface to be brazed. In this case, the wall thicknesses of each of the plurality of flow paths are not uniform, and there are portions where the wall thickness is more than necessary for the structure among the plurality of flow paths.

[0051] On the other hand, in the process of manufacturing the refrigerant manifold 1 of the present embodiment, the mold 12 has a substantially equal wall thickness with respect to a predetermined surface (upper surface 102) in each of the plurality of flow paths 101. For this reason, the refrigerant manifold 1 has no portions where the wall thickness is more than necessary for the structure, and as a result, it can be made lighter than a two-piece structure by aluminum brazing.

[0052] Further, in the manufacturing method of the refrigerant manifold 1 of the present embodiment, in the step of pouring the molten metal (aluminum material 14) into the mold 12, a molten aluminum alloy containing silicon is poured into the mold 12.

[0053] In the above method, the operator pours a molten aluminum alloy containing silicon into the mold 12. Generally, an aluminum alloy containing silicon has a lower thermal conductivity than an aluminum alloy not containing silicon (silicon-free material).

[0054] For this reason, the refrigerant manifold 1 can reduce the heat loss due to heat exchange between the refrigerants flowing through the adjacent flow paths 101, and as a result, the performance of the refrigerant system can be improved.

[0055] Furthermore, in this embodiment, the refrigerant manifold 1 is formed by placing a salt core 16 in a mold 12, pouring molten metal (aluminum material 14) into the mold 12 and allowing it to solidify to cast an intermediate structure 17, and then dissolving and discharging the salt core 16 from the intermediate structure 17 to form multiple flow channels 101.

[0056] According to the above configuration, since the flow path 101 is formed by the salt core 16, the refrigerant manifold 1 does not need to be a structure divided into multiple parts and can be formed as a single unit. Since the refrigerant manifold 1 is formed as a single unit, there is no need to perform aluminum brazing. If aluminum brazing is not performed, there is no need to use expensive silicon-free materials in manufacturing, and inexpensive silicon-containing materials can be used. When silicon-containing materials are used in manufacturing, they have good castability, so there is no need to choose the expensive molten metal forging method, and the low-cost gravity forging method can be chosen. Consequently, the manufacturing cost of the refrigerant manifold 1 can be reduced.

[0057] Although embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims and their equivalents.

[0058] (Note) The above description of embodiments discloses the following technologies: (1) A method for manufacturing a refrigerant manifold, comprising the steps of: arranging a disintegrable core corresponding to a plurality of flow paths in a mold; pouring molten metal into the mold; solidifying the molten metal to cast an intermediate structure; and dissolving and discharging the disintegrable core from the intermediate structure to form the plurality of flow paths. (2) The method for manufacturing a refrigerant manifold according to claim 1, wherein in the step of arranging the disintegrable core that forms the plurality of flow paths in the mold, the disintegrable core forms the plurality of flow paths having a substantially circular cross-section in the radial direction. (3) The method for manufacturing a refrigerant manifold according to claim 2, wherein the mold has substantially the same wall thickness with respect to a predetermined surface in each of the plurality of flow paths. (4) The method for manufacturing a refrigerant manifold according to claim 3, wherein in the step of pouring molten metal into the mold, molten aluminum alloy containing silicon is poured into the mold. (5) A refrigerant manifold in which a disintegrating core is placed in a mold, molten metal is poured into the mold and solidified to cast an intermediate structure, and the disintegrating core is dissolved from the intermediate structure and discharged to form multiple flow channels.

[0059] 1 Refrigerant manifold 10 Main body 12 Mold 14 Aluminum material 16 Salt core 17 Intermediate structure 101, 101a, 101c, 101d, 101e, 101f Flow path d1, d2 Wall thickness of flow path

Claims

1. A method for manufacturing a refrigerant manifold, comprising the steps of:

1. Placing a disintegrable core corresponding to a plurality of flow paths in a mold; 2. Pouring molten metal into the mold; 3. Solidifying the molten metal to cast an intermediate structure; and 4. Dissolving and discharging the disintegrable core from the intermediate structure to form the plurality of flow paths.

2. The method for manufacturing a refrigerant manifold according to claim 1, wherein in the step of arranging the disintegrable cores that form the plurality of flow channels in the mold, the disintegrable cores form the plurality of flow channels having a substantially circular cross-section in the radial direction.

3. The method for manufacturing a refrigerant manifold according to claim 2, wherein the mold has substantially the same wall thickness with respect to a predetermined surface in each of the plurality of flow paths.

4. The method for manufacturing a refrigerant manifold according to claim 3, wherein in the step of pouring molten metal into the mold, molten aluminum alloy containing silicon is poured into the mold.

5. A refrigerant manifold in which a disintegrating core is placed in a mold, molten metal is poured into the mold and solidified to cast an intermediate structure, and the disintegrating core is dissolved and discharged from the intermediate structure to form multiple flow channels.

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