Cooling device manufacturing method

Abstract

To provide a cooler capable of improving heat exchange performance of a cooling liquid flow path without significantly impairing smooth flow of cooling liquid, and a manufacturing method for a cooler capable of efficiently manufacturing a cooler with improved heat exchange performance of a cooling liquid flow path without removing a support member provided in the cooling liquid flow path.SOLUTION: A cooler comprises a cooling liquid flow path arranged around a heating unit and formed of a metal material. The cooling liquid flow path includes a three-dimensional structure having a structure in which unit bodies made of the metal material are regularly arranged. The three-dimensional structure is provided continuously on the inner wall surface of the cooling liquid flow path.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a cooling device and a method for manufacturing a cooling device. [Background technology]

[0002] 2. Description of the Related Art A water jacket having a coolant flow path is provided in an engine block of a vehicle engine.

[0003] It has been known in the past to provide partition walls or ribs in the coolant flow path of a water jacket (see, for example, Patent Documents 1 to 3). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 17255 / 1983 [Patent Document 2] Japanese Utility Model Application Publication No. 59-52123 [Patent Document 3] Japanese Utility Model Application Publication No. 62-43127 Summary of the Invention [Problem to be solved by the invention]

[0005] However, providing partition walls or ribs inside the coolant flow path presents a problem in that the smooth flow of the coolant may be impaired, and heat exchange performance may be reduced.

[0006] In recent years, additive manufacturing (AM) has become popular, using 3D printers to create three-dimensional products using additive manufacturing techniques. Compared to casting, AM makes it easier to create metal products with complex structures using metal materials such as powder metal and metal wire.

[0007] However, when additive manufacturing metal products having hollow portions such as coolant flow paths inside, the hollow portions are prone to deformation during manufacturing. Therefore, manufacturing must be limited to positions that do not cause deformation of the hollow portions, which limits design freedom. Furthermore, to prevent deformation of the hollow portions during manufacturing and improve design freedom, support members that prevent deformation are sometimes integrally molded inside the hollow portions. However, this requires the support members to be removed after manufacturing, which increases the number of steps and reduces quality.

[0008] The present invention aims to provide a cooling device that can improve the heat exchange performance of the coolant flow path without significantly impairing the smooth flow of the coolant, and to provide a method for manufacturing a cooling device that can efficiently manufacture a cooling device with improved heat exchange performance of the coolant flow path without the need to remove support members provided in the coolant flow path. [Means for solving the problem]

[0009] (1) The cooling device of the present invention is a cooling device (e.g., a water jacket 2 described later) that is arranged around a heat-generating part (e.g., a cylinder liner 11 described later) and has a coolant flow path (e.g., a coolant flow path 21 described later) formed of a metal material, and the coolant flow path has a three-dimensional structure (e.g., a lattice assembly 3 described later) therein that has a structure in which unit bodies (e.g., a lattice structure 31 described later) made of the metal material are regularly arranged, and the three-dimensional structure is provided continuously on the inner wall surface (e.g., an inner wall surface 211 described later) of the coolant flow path.

[0010] (2) The manufacturing method of the cooling device according to the present invention is a manufacturing method of a cooling device (e.g., a water jacket 2 described below) that is arranged around a heat-generating part (e.g., a cylinder liner 11 described below) and has a coolant flow path (e.g., a coolant flow path 21 described below) formed of a metal material, in which a three-dimensional structure (e.g., a lattice assembly 3 described below) having a structure in which units (e.g., a lattice structure 31 described below) made of the metal material are regularly arranged inside the coolant flow path, is continuously provided from one side (e.g., one side 211a described below) to the other side (e.g., the other side 211b described below) of the inner wall surface (e.g., an inner wall surface 211 described below) of the coolant flow path, and the cooling device is additively manufactured using a metal material while the three-dimensional structure functions as a support member. [Effects of the Invention]

[0011] According to the above (1), the heat transfer area of ​​the coolant flow path is increased by the three-dimensional structure continuously provided on the inner wall surface of the coolant flow path. The three-dimensional structure, which has a structure in which units are regularly arranged, allows the coolant to flow through without significantly impairing the smooth flow of the coolant, thereby improving the heat exchange performance of the coolant flow path.

[0012] According to (2) above, the three-dimensional structure can be used as a support member to prevent deformation of the coolant flow path during modeling, so the modeling posture is not limited, improving design freedom. After modeling, there is no need to remove the three-dimensional structure from inside the coolant flow path, and the three-dimensional structure makes it easy to construct a coolant flow path with an increased heat transfer area. Therefore, cooling devices with improved heat exchange performance in the coolant flow path due to the three-dimensional structure can be efficiently manufactured. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a perspective view of an engine block having a cooling device. [Figure 2] FIG. 2 is a vertical cross-sectional view of the engine block shown in FIG. [Figure 3] FIG. 3 is an enlarged view of a cross section taken along line AA in FIG. 2. [Figure 4] FIG. 4 is an enlarged perspective view showing the lattice structure of part B in FIG. 3. [Figure 5] FIG. 2 is a perspective view showing a state in which the engine block shown in FIG. 1 is manufactured by additive manufacturing. [Figure 6] 1 is a vertical cross-sectional view of a rotating electrical machine having a cooling device; DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Figures 1 and 2 show an engine block 1. This engine block 1 shows only a portion having two cylinder bores 10, 10 out of a plurality of cylinder bores provided in an engine serving as a power unit.

[0015] 2, the engine block 1 contains cylinder liners 11, 11 that define two cylinder bores 10, 10, an intake port 12 and an exhaust port 13 that communicate with the cylinder bores 10, 10, respectively, and a water jacket 2. The engine block 1 is an integrally molded product that is molded integrally from a metal material such as aluminum that has good thermal conductivity.

[0016] In the engine block 1, the cylinder liner 11 is a heat-generating part that generates heat when the engine is running. Therefore, the area around the cylinder liner 11 is to be cooled by coolant. The water jacket 2 is a cooling device that is provided around the cylinder liner 11, intake port 12, and exhaust port 13 and cools the area around the cylinder liner 11, including the intake port 12 and exhaust port 13, with coolant.

[0017] The water jacket 2 has a coolant flow path 21 consisting of a cavity surrounding the cylinder liner 11, the intake port 12, and the exhaust port 13. A lattice assembly 3 is provided inside the coolant flow path 21. The lattice assembly 3 is composed of a plurality of lattice structures 31 made of the same metal material as the metal material forming the engine block 1. The lattice assembly 3 of this embodiment is a three-dimensional structure in which the lattice structures 31, which are unit bodies made of a metal material, are regularly arranged in three dimensions. The lattice assembly 3 is composed by connecting a plurality of the lattice structures 31, which are unit bodies. A space is formed between adjacent lattice structures 31, 31, through which the coolant can flow.

[0018] The lattice structure 31 is a three-dimensional lattice-shaped unit that branches out like branches. As shown in FIG. 4 , the lattice structure 31 of this embodiment has a plurality of columnar portions 311 and a plurality of oblique portions 312. A space through which the coolant can flow is formed between the plurality of columnar portions 311 and the plurality of oblique portions 312. The columnar portions 311 extend parallel to one another. The oblique portions 312 extend so as to intersect obliquely with the columnar portions 311. The plurality of oblique portions 312 intersect with one another. However, the lattice structure provided inside the coolant flow path 21 may be any three-dimensional structure that branches out like branches and allows the coolant to flow inside the lattice structure, and is not limited to the one shown in the figure.

[0019] The lattice assembly 3 is formed by connecting a plurality of lattice structures 31 along the extending direction of the columnar portions 311 (the vertical direction in FIGS. 3 and 4). A plurality of lattice assemblies 3 may be arranged adjacent to each other in a direction perpendicular to the extending direction of the columnar portions 311 of the lattice structure 31. A plurality of lattice assemblies 3 may be provided in blocks inside the coolant flow path 21.

[0020] The lattice assembly 3 is provided contiguous with the inner wall surface 211 of the coolant flow path 21. More specifically, at least a portion of the lattice assembly 3 is in contact with the inner wall surface 211 of the coolant flow path 21 and is molded integrally with the inner wall surface 211. This thermally connects the lattice assembly 3 to the inner wall surface 211 of the coolant flow path 21. The lattice assembly 3 increases the heat transfer area of ​​the coolant flow path 21 in the water jacket 2. The lattice assembly 3, which connects multiple lattice structures 31, allows the coolant to flow between adjacent columnar portions 311, 311, between adjacent diagonal portions 312, 312, and between adjacent columnar portions 311 and diagonal portions 312. As a result, the water jacket 2 does not significantly impair the smooth flow of the coolant, and improves the heat exchange performance of the coolant flow path 21.

[0021] 3, the lattice assembly 3 of this embodiment is provided continuously from one surface 211a to the other surface 211b of the inner wall surface 211 of the coolant flow path 21. More specifically, one end of the lattice assembly 3 is in contact with the one surface 211a of the inner wall surface 211 of the coolant flow path 21 and is molded integrally with the one surface 211a, and the other end of the lattice assembly 3 is in contact with the other surface 211b of the inner wall surface 211 of the coolant flow path 21 and is molded integrally with the other surface 211b.

[0022] The engine block 1, which is an integrally molded product like this, is additively manufactured by a 3D printer using a metal material (metal powder, metal wire, etc.) such as aluminum, which has good thermal conductivity. When powdered metal is used as the metal material, additive manufacturing using a 3D printer involves irradiating the powdered metal spread on a base plate with a laser or electron beam as a heat source to melt and solidify the part to be molded, and then moving the base plate and spreading new powdered metal, repeating these steps, for example, along the direction shown by the arrow in Figure 5, to three-dimensionally additively manufacture the engine block 1 having the water jacket 2.

[0023] At this time, a lattice assembly 3, in which a plurality of lattice structures 31 made of a metal material are connected, is formed continuously inside the coolant flow path 21 of the water jacket 2 provided in the engine block 1, from one surface 211a to the other surface 211b of the inner wall surface 211 of the coolant flow path 21. Therefore, the water jacket 2 is additively manufactured with the lattice assembly 3 functioning as a support member.

[0024] As a result, when forming the hollow coolant flow path 21, the lattice assembly 3, which is molded integrally with the coolant flow path 21, can be used as a support member to prevent deformation of the coolant flow path 21. Therefore, the forming posture of the engine block 1 is not limited to the posture shown in FIG. 5, improving design freedom. After forming, there is no need to remove the lattice assembly 3 from inside the coolant flow path 21, and the lattice assembly 3 makes it easy to form a coolant flow path 21 with an increased heat transfer area. Therefore, the water jacket 2, in which the heat exchange performance of the coolant flow path 21 is improved by the lattice assembly 3, can be efficiently manufactured on the engine block 1.

[0025] The one and the other surfaces of the inner wall surface 211 of the coolant flow path 21 are not limited to two surfaces arranged opposite each other among the inner wall surface 211 of the coolant flow path 21. The one and the other surfaces of the inner wall surface 211 of the coolant flow path 21 may be two surfaces that contact each other.

[0026] In summary, the water jacket 2 according to this embodiment has the following advantages. The water jacket 2, which is a cooling device according to this embodiment, is disposed around the cylinder liner 11, which is a heat-generating part of the engine block 1, and is a cooling device having a coolant flow path 21 formed of a metallic material. The coolant flow path 21 has a lattice assembly 3 (a three-dimensional structure) therein, which has a structure in which lattice structures 31 (units) made of a metallic material are regularly arranged. The lattice assembly 3 is provided contiguous to the inner wall surface 211 of the coolant flow path 21. This increases the heat transfer area of ​​the coolant flow path 21 due to the lattice assembly 3. The lattice assembly 3 allows the coolant to flow between adjacent lattice structures 31, 31 without significantly impairing the smooth flow of the coolant, thereby improving the heat exchange performance of the coolant flow path 21.

[0027] The manufacturing method for the water jacket 2 according to this embodiment is a manufacturing method for the water jacket 2, which is a cooling device arranged around the cylinder liner 11, a heat-generating part in the engine block 1, and which includes a coolant flow path 21 formed of a metallic material. A lattice assembly 3 (a three-dimensional structure) having a regularly arranged lattice structure 31 (units) made of a metallic material is continuously provided inside the coolant flow path 21 from one surface 211a to the other surface 211b of the inner wall surface 211 of the coolant flow path 21. The water jacket 2 is additively manufactured using a metallic material while the lattice assembly 3 functions as a support member. This allows the lattice assembly 3 to be used as a support member to prevent deformation of the coolant flow path 21 during manufacturing, thereby eliminating limitations on the manufacturing orientation of the engine block and the water jacket 2 and improving the design flexibility of the engine block and the water jacket 2. After manufacturing, there is no need to remove the lattice assembly 3 from inside the coolant flow path 21, and the lattice assembly 3 allows for easy construction of a coolant flow path 21 with an increased heat transfer area. Therefore, the water jacket 2 in which the heat exchange performance of the coolant flow path 21 is improved by the lattice assembly 3 can be efficiently manufactured.

[0028] In the above embodiment, a lattice assembly 3 formed by connecting a plurality of lattice structures 31 has been given as an example of a three-dimensional structure having a structure in which units are regularly arranged, but the three-dimensional structure having a structure in which units are regularly arranged is not limited to the lattice assembly 3. A three-dimensional structure having a structure in which units are regularly arranged may be, for example, a gyroid structure in which a plurality of minimal curved surfaces are connected in three directions.

[0029] In the above embodiment, the water jacket 2 provided in the engine block 1 of the engine has been given as an example of the cooling device, but the cooling device may be any device that has a coolant flow path for cooling a heat-generating part that is to be cooled, and is not limited to a water jacket provided in the engine block 1 of the engine. For example, the cooling device may be a water jacket 5 provided in a rotating electric machine 4 as a power unit, as shown in Fig. 6.

[0030] The rotating electric machine 4 has a substantially cylindrical stator core 41 extending in the axial direction, and a rotor 42 rotatably supported in an axial hole 41a of the stator core 41. The stator core 41 is made of an iron-based metal material, and houses coils 43 in a plurality of slots 41b.

[0031] When the rotating electric machine 4 is driven, heat from the coils 43 is transferred to the stator core 41, causing the stator core 41 to generate heat. The water jacket 5 cools the coils 43 via the stator core 41. In this embodiment, the stator core 41 is a heat-generating part to be cooled by the water jacket 5.

[0032] The water jacket 5 is disposed radially outside the stator core 41 of the rotating electric machine 4. The water jacket 5 has a housing 51 disposed on the outer periphery of the stator core 41, and a coolant flow path 52 provided inside the housing 51 and through which a coolant flows to cool the stator core 41. A lattice assembly (not shown) similar to that described above is integrally provided inside the coolant flow path 52.

[0033] This water jacket 5 also achieves the same effects as the water jacket 2 by additively manufacturing the housing 51, coolant flow path 52, and lattice assembly (not shown) together using an aluminum-based metal material with good thermal conductivity. [Explanation of symbols]

[0034] 2 Water jacket (cooling device) 21 Coolant flow path 211 Inner wall surface 211a One side 211b Other side 3 Lattice assembly (3D structure) 31 Lattice structure (unit) 41 Stator core (heat generating part) 11 Cylinder liner (heat generating part) 5 Water jacket (cooling device) 52 Coolant flow path

Claims

[Claim 1] A manufacturing method of a cooling device, in which a cooling device is disposed around a heat generating portion and has a coolant flow path formed of a metal material, is additively manufactured along one direction using a metal material, A method for manufacturing a cooling device, wherein, during additive manufacturing of the coolant flow path, a plurality of three-dimensional structures having a structure in which unit bodies made of the metal material are regularly arranged inside the coolant flow path are continuously provided from one inner wall surface to the other inner wall surface of two inner wall surfaces that intersect in the one direction inside the coolant flow path and are arranged at intervals along the one direction, thereby forming the plurality of three-dimensional structures while allowing them to function as support members, and forming a space between adjacent three-dimensional structures in the plurality of three-dimensional structures through which coolant can flow without the three-dimensional structure being provided between the two inner wall surfaces.

Images