Metal-resin composite and method for manufacturing metal-resin composite

Abstract

An extrusion material (20) comprises: a first lateral wall (21) that forms an exposure surface (21a) where a metal is exposed therefrom, and that is to be close to and opposite to a first inner surface (92a) of an accommodation part (92) of a first mold (91) in an accommodated state where the extrusion material (20) is accommodated in the accommodation part (92); a second lateral wall (22) that forms a covered surface (22a) covered with a resin material (50), and that defines a cavity (90a) filled with the resin material (50), together with a second inner surface (92b) of the accommodation part (92) in the accommodated state; and a first circumscribed wall (23) that forms an outer surface (23a) covered with the resin material (50), and that connects end parts of the first lateral wall (21) and the second lateral wall (22) on the mold opening direction side in the accommodated state. The outer surface (23a) of the first circumscribed wall (23) inclines from the second lateral wall (22) toward the first lateral wall (21) so as to be directed toward the mold opening direction side in the accommodated state of the extrusion material (20).

Description

Metal-resin composite and its manufacturing method

[0001] The present disclosure relates to a metal-resin composite and a method for producing the same.

[0002] Various structures and manufacturing methods have been proposed for metal-resin composites used in structural parts such as vehicle frames. For example, in the composite disclosed in Patent Document 1, a thermosetting carbon fiber reinforced plastic (CFRP) is bonded to the surface of an aluminum extrusion with an adhesive. In the composite disclosed in Patent Document 2, the aluminum plate and the CFRP are integrated by hot pressing the CFRP onto the aluminum plate.

[0003] JP 2017-119422 A JP 2020-104411 A

[0004] When applying the hot press technique exemplified in Patent Document 2 to the manufacture of composites containing aluminum extrusions, it is considered necessary to prepare a die that takes into account the tolerances of the aluminum extrusions and forms a suitable gap between the die and the aluminum extrusions, which are assumed to have standard dimensions. This allows the aluminum extrusions, formed within tolerances, to be properly placed in the die each time a composite is manufactured. On the other hand, the aluminum extrusions are hot extruded as taught in Patent Document 1. Therefore, twisting and bending are likely to occur during extrusion, making it difficult to achieve high dimensional accuracy for the aluminum extrusions.

[0005] Considering the low dimensional accuracy of aluminum extrusions, it is thought that the gap between the die and the aluminum extrusion needs to be significantly larger than the gap between the mating surfaces of the dies. If this happens, the position of the aluminum extrusion will be unstable relative to the die during hot pressing, and there is a risk that the resin will unintentionally flow into the gap.

[0006] An object of the present disclosure is to prevent resin material from unintentionally flowing into the gap between a mold and an extruded material when manufacturing a metal-resin composite by press-molding a resin material onto an extruded material.

[0007] One aspect of the present disclosure is a method for manufacturing a metal-resin composite by press-molding a resin material into a metal extrusion, the method comprising: preparing a mold including a first mold forming a housing portion that houses at least a portion of the extrusion material, and a second mold that is movable in a mold closing direction and a mold opening direction relative to the first mold; accommodating the extrusion material in the housing portion and placing the resin material in the first mold; moving the second mold in the mold closing direction to form a cavity defined by the extrusion material and the mold; and pressurizing the resin material to fill the cavity. a first side wall that is closely opposed to a first inner surface of the accommodating section in a storage state in which the extruded material is stored in the accommodating section; a second side wall that forms a covering surface that is coated with the resin material and that, together with the second inner surface of the accommodating section in the storage state, defines the cavity; and an external connecting wall that forms an outer surface that is coated with the resin material and connects end portions of the first side wall and the second side wall on the mold opening direction side in the storage state, wherein the outer surface is inclined from the second side wall toward the first side wall in the storage state.

[0008] According to the above configuration, when the resin material is pressurized, the molding pressure acts on the outer surface of the external connection wall in the mold closing direction via the resin material. The outer surface of the external connection wall is inclined from the second side wall toward the first side wall toward the mold opening direction. Therefore, the extruded material is pushed in the mold closing direction and toward the first inner surface of the accommodating portion. This closes the gap between the first side wall and the first inner surface, bringing the exposed surface of the first side wall into close contact with or in close contact with the first inner surface. This prevents the resin material from solidifying on the exposed surface, properly exposing the metal on the exposed surface, eliminating or significantly simplifying the process of removing excess resin after demolding. Meanwhile, a gap is formed between the coating surface and the second inner surface, but this gap functions as a cavity into which the resin material to be coated onto the coating surface is intentionally poured. The resin material properly solidifies on the coating surface and the outer surface, properly coating the second side wall and the external connection wall with the resin material.

[0009] The covering surface may be inclined in the mold closing direction in the housed state so as to move away from the first side wall.

[0010] With this configuration, the molding pressure also acts on the covered surface via the resin material that has flowed into the gap between the covered surface and the second inner surface. Because the covered surface is inclined toward the second inner surface in the mold closing direction, the extruded material is pushed toward the first inner surface of the housing section by the resin material that flows in the mold closing direction. This makes it even easier to close the gap between the exposed surface and the first inner surface.

[0011] The extrusion may further have a protrusion that protrudes from the covering surface at a corner portion between the external connection wall and the second side wall.

[0012] According to the above configuration, the resin material is hardened around the protrusions, making it difficult for the resin material to peel off from the extruded material.

[0013] The first mold may form a groove that is defined by an end of the exposed surface of the first side wall on the mold closing direction side and that forms a part of the cavity.

[0014] According to the above configuration, a thick resin material can be provided at the corner portion between the first side wall and the external connection wall, making it difficult for the resin material to peel off from the extruded material.

[0015] The extruded material and the resin material may form a fitting structure at an end of the second side wall on the mold closing direction side.

[0016] According to the above configuration, the resin material solidifies in a state where it is fitted with the extruded material at the end of the second side wall, and the resin material is less likely to peel off from the extruded material.

[0017] Another aspect of the present disclosure provides a metal-resin composite formed by integrating a resin material with a metal extrusion material by press molding, wherein the extrusion material has a first side wall that forms an exposed surface where the metal is exposed, a second side wall that forms a covered surface that is covered with the resin material, and an external connecting wall that connects ends of the first side wall and the second side wall and forms an outer surface that is covered with the resin material, and the outer surface of the external connecting wall slopes from the second side wall toward the first side wall toward the outer surface of the resin material.

[0018] According to the above configuration, molding pressure is applied to the outer surface coated with the resin material via the resin material, thereby allowing the first side wall of the extruded material to be tightly attached to the mold used for press molding. This prevents the resin material from solidifying on the exposed surface where the metal should be exposed, and allows the resin material to properly solidify on the coated surface where the resin material should be coated. This makes it possible to provide a metal-resin composite with high production efficiency.

[0019] According to the present disclosure, when manufacturing a metal resin composite by press-molding a resin material onto an extruded material, it is possible to prevent the resin material from unintentionally flowing into the gap between the mold and the extruded material.

[0020] FIG. 1 is a side view of an electric vehicle. FIG. 2 is a perspective view of an automobile battery case as an application example of a metal resin composite according to an embodiment. FIG. 3 is a perspective view of the automobile battery case cut along line III-III in FIG. 2. FIG. 4 is a cross-sectional perspective view showing an extruded material, a mold, and an insert prepared in the manufacture of a metal resin composite. FIG. 5 is a front view of an extruded material. FIG. 6 is a cross-sectional view showing the extruded material and the mold in a state where a resin material has been placed. FIG. 7 is a cross-sectional view showing the extruded material and the mold in a state where the resin material has been hot-pressed. FIG. 8 is a cross-sectional perspective view showing the extruded material and the mold after the hot-pressing is completed.

[0021] Hereinafter, embodiments will be described with reference to the drawings. The same or corresponding reference numerals are assigned the same reference numerals, and detailed descriptions thereof will be omitted.

[0022] Referring to FIG. 1 , automobile 1 is an electric vehicle that runs by driving a motor with power supplied from a battery 2. Automobile 1 is a vehicle that runs on electricity, and may be, for example, an electric vehicle or a plug-in hybrid vehicle. The type of vehicle is not particularly limited, and may be a passenger car, truck, work vehicle, or other mobility vehicle. The following description will be given taking an example of a passenger car-type electric vehicle as the electric vehicle.

[0023] The automobile 1 is equipped with a motor and high-voltage equipment (not shown) in a front portion 3 of the vehicle. The automobile 1 also has an automobile battery case 10 that houses a battery 2 and occupies almost the entire surface under the floor of the passenger compartment 5 in a central portion 4 of the vehicle body.

[0024] 1, the front-to-rear direction (vehicle length direction) of the automobile 1 is indicated as the X direction, and the up-down direction (vehicle height direction) is indicated as the Z direction. The same notation is used in the subsequent figures, and in Fig. 2 and subsequent figures, the width direction (vehicle width direction) of the automobile 1 is indicated as the Y direction.

[0025] Referring to FIG. 2 , the battery case 10 includes a frame 11 in which a plurality of extrusion members 20 and 30 are arranged in a frame shape, and a resin material 50 molded integrally with the frame 11 .

[0026] The battery case 10 is one suitable application example of the metal-resin composite body 100 according to the embodiment. The metal-resin composite body 100 is formed by integrating a resin material 50 with metal extrusion members 20, 30 by press molding. The metal material of the extrusion members 20, 30 is not particularly limited. Light alloys such as aluminum alloys and magnesium alloys are suitable examples of metal materials, and contribute to achieving both lightweight and high rigidity in structural components. Unless otherwise specified below, the extrusion members 20, 30 are made of aluminum alloys.

[0027] Although detailed illustrations are omitted, the extrusion material 20 is obtained by heating and compressing a billet-shaped metal material within the main body of an extrusion molding machine and then extruding it through a die attached to the main body. After being extruded from the die, required processes such as cooling, pulling, and cutting are performed. The cross section of the extrusion material 20 is determined by the shape of the die, so it is uniform in its extension direction (extrusion direction). However, twists and bends occur due to hot forming. Each element of the extrusion material 20 extends in the extension direction and is seamlessly integrated with each other. The same is true for the extrusion material 30.

[0028] The resin material 50 is obtained by press-molding a compound in a manufacturing apparatus 9 (see FIG. 6 ) for the metal-resin composite 100. The compound may be a sheet-shaped SMC (sheet molding compound) or a bulk-molding compound (BMC) formed into a block. SMC or BMC is realized by a fiber-reinforced plastic (FRP) in which fibers are impregnated into a matrix resin. The matrix resin contains a thermosetting resin, such as unsaturated polyester, as its main component, and additives are mixed into the main component. The additives include, for example, a mold release agent. The fibers, such as glass fiber or carbon fiber, are cut short and randomly oriented within the compound. However, the resin material 50 is not limited to a thermosetting resin and may also be a thermoplastic resin. In the following description, the resin material 50 is made of SMC as a mere example.

[0029] The frame 11 has, for example, a rectangular frame shape in a plan view. The frame 11 includes a pair of side members 12, 13, a front member 14, a rear member 15, and multiple cross members 16. The pair of side members 12, 13 extend in the vehicle length direction. The front member 14 connects the front ends of the pair of side members 12, 13 to each other in the vehicle width direction. The rear member 15 connects the rear ends of the pair of side members 12, 13 to each other in the vehicle width direction. The multiple cross members 16 are arranged at intervals between the front member 14 and the rear member 15 and connect the pair of side members 12, 13 to each other in the vehicle width direction.

[0030] In this embodiment, the pair of side members 12, 13, the front member 14, and the rear member 15 are made of extruded members 20. The cross member 16 is made of an extruded member 30. The extension direction of each member constituting the frame 11 corresponds to the extrusion direction of the extruded member constituting that member when it is molded. The extruded members 20 and 30 have mutually different cross-sectional shapes.

[0031] The ends of two adjacent members among the pair of side members 12, 13, front member 14, and rear member 15 are cut at 45 degrees (so-called miter cuts) and butt together. Both end faces of each cross member abut against or are close to the inner surfaces of the pair of side members 12, 13, respectively.

[0032] The multiple extrusions (i.e., the multiple members that make up the frame 11) are connected to one another via the resin material 50. However, among the pairs of two adjacent members, there may be pairs where the two members are welded to one another at the butt joint, or pairs where the two members are fastened to one another via a bracket. Conversely, among the pairs of two adjacent members, there are quite a few pairs that are not connected to one another by welding or fastening. By eliminating welding and fastening as much as possible, the number of steps required to manufacture the battery case 10 can be reduced.

[0033] The resin material 50 has a bottom wall 51, a peripheral wall 52, and a flange wall 53. The bottom wall 51 is disposed below the frame 11 and is embedded in the lower surface of the frame 11. The lower ends of the pair of side members 12, 13, the front member 14, the rear member 15, and the multiple cross members 16 are connected to one another via the bottom wall 51. The peripheral wall 52 is disposed circumferentially on the horizontal outer side of the frame 11 and is embedded in the outer surface of the frame 11. The lower end of the peripheral wall 52 is continuous with the bottom wall 51. Adjacent two of the pair of side members 12, 13, the front member 14, and the rear member 15 are also connected to one another via the peripheral wall 52. The flange wall 53 extends horizontally outward from the peripheral wall 52.

[0034] A metal joining member 41 having a joining structure with another member (e.g., a body frame such as a side sill) is embedded in the flange wall 53. The resin material 50 has a plurality of ridges 54 protruding upward from the bottom wall 51. Each ridge 54 extends in the vehicle width direction within a region formed between two adjacent members of the front member 14, the plurality of cross members 16, and the rear member 15. A metal joining member 42 having a joining structure with the battery 2 (see FIG. 1 ) is embedded in the ridges 54. An example of the joining member 41 is a sleeve, and an example of the joining member 42 is a metal nut.

[0035] 3, the extrusion 20 has a generally rectangular cross section. The same is true for the extrusion 30. The extrusion 20 has a first side wall 21, a second side wall 22, a first external connecting wall 23, a second external connecting wall 24, and one or more internal connecting walls 25a, 25b. The extrusion 30 has a first side wall 31, a second side wall 32, a first external connecting wall 33, a second external connecting wall 34, one or more internal connecting walls 35a, 35b, and a pair of extended side walls 36a, 36b.

[0036] In this embodiment, the positions of the extrusion members 20, 30 and the resin material 50 are upside down during use of the battery case 10 and during manufacture of the battery case 10. During use of the battery case 10, the first external connection walls 23, 33 are positioned on the lower side in the vehicle height direction. The bottom wall 51 of the resin material 50 is embedded in the outer surfaces of the first external connection walls 23, 33, which serve as the lower surfaces of the frame 11. The second external connection walls 24, 34 are positioned on the upper side in the vehicle height direction.

[0037] During use of the metal-resin composite 100 as the battery case 10, the first external connection walls 23, 33 are bottom walls of the extrusion members 20, 30, and the second external connection walls 24, 34 are top walls of the extrusion members 20, 30. Here, with reference to Figure 3, the configuration of the extrusion members 20, 30 will be described according to the posture of the battery case 10 during use.

[0038] The first side wall 21 of the extrusion member 20 extends upward from a widthwise edge of the first external connecting wall 23. The second side wall 22 of the extrusion member 20 extends upward from a widthwise edge of the first external connecting wall 23 on the other side.

[0039] The width direction of the first external connection wall 23 corresponds to the width direction of the extrusion material 20. The width direction of the extrusion material 20 is a direction perpendicular to both the extrusion direction and the height direction of the extrusion material 20. When the extrusion material 20 forms the side members 12, 13, the width direction of the extrusion material 20 corresponds to the vehicle width direction. When the extrusion material 20 forms the front member 14 or the rear member 15, the width direction of the extrusion material 20 corresponds to the vehicle length direction. One width direction side of the first external connection wall 23 corresponds to the horizontal inner side of the battery case 10, and the other width direction side corresponds to the horizontal outer side of the battery case 10.

[0040] The outer surface of the first side wall 21 constitutes the horizontal inner surface of the frame 11. The resin material 50 is not embedded in or coated on the inner surface of the frame 11 (the outer surface of the first side wall 21 of the extrusion member 20). The outer surface of the second side wall 22 constitutes the horizontal outer surface of the frame 11. The resin material 50 is embedded in the outer surface of the frame 11. The outer surface of the first side wall 21 is not coated with the resin material 50 and therefore constitutes an "exposed surface 21a" where the aluminum alloy used as the material for the extrusion member 20 should be exposed in its pure form, at least immediately after demolding. The outer surface of the second side wall 22 is coated with the resin material 50 and constitutes a "coated surface 22a" in which the peripheral wall 52 is embedded. Furthermore, the outer surface 23a of the first external connecting wall 23 is also coated with the resin material 50 and constitutes a "coated surface" in which the bottom wall 51 is embedded.

[0041] The second outer connecting wall 24 of the extruded material 20 connects the upper ends of the first side wall 21 and the second side wall 22 to each other in the width direction of the extruded material 20. In this embodiment, the extruded material 20 has two inner connecting walls 25a, 25b. The two inner connecting walls 25a, 25b are arranged spaced apart in the vertical direction in a hollow space surrounded by the first side wall 21, the second side wall 22, the first outer connecting wall 23, and the second outer connecting wall 24. Each inner connecting wall 25a, 25b connects the inner surfaces of the first side wall 21 and the second side wall 22 to each other in the width direction of the extruded material 20.

[0042] The extrusion member 30 also has two internal connection walls 35a, 35b. The first side wall 31, the second side wall 32, the first external connection wall 33, the second external connection wall 34, and the two internal connection walls 35a, 35b of the extrusion member 30 are the same as those of the extrusion member 20. The extrusion member 30 is disposed inside a case surrounded by a pair of side members 12, 13, a front member 14, and a rear member 15. Both the outer surfaces of the first side wall 31 and the second side wall 32 are "exposed surfaces" where the surrounding wall 52 is not embedded. The pair of extended side walls 36a, 36b extend from the first side wall 31 and the second side wall 32, respectively, and protrude downward relative to the first external connection wall 33. The resin material 50 is embedded in the area surrounded by the pair of extended side walls 36a, 36b and the first external connection wall 33. This increases the bonding strength between the resin material 50 and the extrusion member 30. The outer surface of the first outer connecting wall 33 and the inner surfaces of the pair of extension side walls 36a, 36b are covered with a resin material 50, and are "covered surfaces" in which the bottom wall 51 is embedded.

[0043] 4, in a manufacturing method of a metal resin composite 100 as a battery case 10, a resin material 50 is integrated with extrusion materials 20, 30 by press molding using a mold 90. The up-down direction corresponds to the mold opening and closing direction of the mold 90. In a manufacturing device 9 for the metal resin composite 100, the mold opening direction is upward and the mold closing direction is downward. The extrusion material 20 is placed in an orientation relative to the manufacturing device 9 such that the first external connection wall 23 is located upward and the second external connection wall 24 is located downward. The same applies to the extrusion material 30.

[0044] During manufacture of the metal-resin composite body 100 as the battery case 10, the first external connection walls 23, 33 are the top walls of the extrusion members 20, 30, and the second external connection walls 24, 34 are the bottom walls of the extrusion members 20, 30, as opposed to during use. Here, with reference to Figure 4, the extrusion members 20, 30 and other components will be described according to the position during manufacture of the metal-resin composite body 100.

[0045] The manufacturing apparatus 9 mainly includes a mold 90, a drive unit 9a, and a heating unit 9b. The mold 90 includes a first mold 91 and a second mold 99 (see FIG. 6). The first mold 91 is configured as a fixed mold, a lower mold, or a die. The second mold 99 is configured as a movable mold, an upper mold, or a punch. The second mold 99 is driven by the drive unit 9a and is movable in a mold closing direction and a mold opening direction relative to the first mold 91.

[0046] The first die 91 forms a housing portion 92 that houses at least a portion of the extruded material 20 and a housing portion 93 that houses at least a portion of the extruded material 30 .

[0047] The first mold 91 has a base 94 and a shoulder 95. The upper surface of the base 94 forms a horizontal lower molding surface 94a. The shoulder 95 protrudes upward from the periphery of the base 94, and the inner surface of the shoulder 95 extends upward from the lower molding surface 94a.

[0048] Although detailed illustration is omitted, the inner surface of the shoulder portion 95, in a cross section perpendicular to the mold opening / closing direction, has the same shape as the planar view of the combination of the bottom wall 51 and the flange wall 53 of the finished metal-resin composite body 100. In this example, as can be seen from FIG. 2 , the planar view of this combination is rectangular, so the shoulder portion 95 has a rectangular window frame shape in plan view. The lower part of the inner surface of the shoulder portion 95 forms a vertical side molding surface 95a. The shape of the side molding surface 95a is transferred to the circumferential surface of the flange wall 53. The upper part of the inner surface of the shoulder portion 95 forms a lower mating surface 95b.

[0049] The accommodation portions 92 and 93 are recessed into the lower molding surface 94a. The accommodation portion 92 has an inner surface with a U-shaped cross section and is configured as a groove that opens to the lower molding surface 94a. The inner surface of the accommodation portion 92 includes a pair of first and second inner surfaces 92a and 92b that extend downward and are continuous with the lower molding surface 94a, and an inner bottom surface 92c that connects the lower ends of the first and second inner surfaces 92a and 92b. The accommodation portion 93 is similar to this. The inner surface of the accommodation portion 93 includes a pair of inner surfaces 93a and 93b and an inner bottom surface 93c. A groove 94b is formed at the upper edge of one widthwise side of the accommodation portion 92.

[0050] The configuration and operation of the manufacturing apparatus 9 will be described below in accordance with the procedure of the manufacturing method of the metal resin composite 100. When manufacturing the metal resin composite 100, first, a mold 90 is prepared. Next, the extrusion materials 20 and 30 are accommodated in the accommodation portions 92 and 93 of the prepared first mold 91.

[0051] Regarding preparation of the mold 90, the second mold 99 is positioned at a predetermined retreat position away from the first mold 91 in the mold opening direction.

[0052] Although detailed illustration of the extrusion material 30 being accommodated in the accommodation portion 93 is omitted, referring to FIG. 4 , the extrusion material 30 is inserted from above into the accommodation portion 93 with the pair of extended side walls 36a, 36b protruding upward relative to the first external connection wall 33. The second external connection wall 34 abuts against the inner bottom surface 93c of the accommodation portion 93, the first side wall 31 is adjacent to the inner surface 93a, and the second side wall 32 is adjacent to the inner surface 93b. A pair of protrusions provided at the tip of each extended side wall 36a, 36b are in close contact with the pair of inner surfaces 93a, 93b, respectively. Note that the cross-sectional shape of the extrusion material 30 is line-symmetrical with respect to a center line passing through the center in the width direction in the up-down direction. Therefore, the first side wall 31 may be adjacent to the inner surface 93b, and the second side wall 32 may be adjacent to the inner surface 93a.

[0053] 4 , the extrusion material 20 is inserted into the accommodation portion 92 from above with the first outer connection wall 23 facing upward. The second outer connection wall 34 abuts against the inner bottom surface 92c of the accommodation portion 92, the first side wall 21 is adjacent to the first inner surface 92a, and the second side wall 22 is adjacent to the second inner surface 92b.

[0054] The shape of the extrusion material 20 will now be described in more detail with reference to Figures 4 and 5. Note that the up-down direction on the paper in Figures 4 and 5 coincides with the up-down direction during manufacturing, with the first outer connection wall 23 facing upward.

[0055] The outer surface 23a of the first outer connecting wall 23 is inclined toward the mold opening direction (upward during manufacturing, downward during use) from the second side wall 22 toward the first side wall 21. The second outer connecting wall 24 is not inclined in this manner. The inclination angle θ23 of the outer surface 23a with respect to the second outer connecting wall 24 is 5 to 25 degrees. In this regard, if the inclination angle θ23 is too small (e.g., less than 5 degrees), the lateral force generated in response to the downward molding pressure is reduced, and the extrusion material 20 is less pressed against the first inner surface 92a. If the inclination angle θ23 is too large (e.g., greater than 25 degrees), the downward molding pressure is less likely to be received, and the extrusion material 20 is less pressed against the first inner surface 92a. By setting the inclination angle θ23 as described above, the extrusion material 20 can be appropriately pressed against the first inner surface 92a based on the downward molding pressure.

[0056] The first external connection wall 23 extends toward the other widthwise side relative to the second side wall 22. Due to this extension, a protrusion 26 protruding toward the other widthwise side is provided at the corner between the first external connection wall 23 and the second side wall 22. The end face of the protrusion 26 is inclined toward the other widthwise side as it approaches the mold closing direction. The inclination of the end face of the protrusion 26 relative to the widthwise direction (horizontal direction) is greater than the inclination of the outer surface of the first external connection wall 23 relative to the widthwise direction.

[0057] The covering surface 22a, which is the outer surface of the second side wall 22, is inclined toward the mold closing direction (downward during manufacturing, upward during manufacturing) so as to move away from the first side wall 21 of the extruded material 20 (i.e., toward the second inner surface 92b of the storage section 92). The inclination angle θ22 of the covering surface 22a with respect to the extension direction of the first side wall 21 is 1 to 10 degrees. In this regard, if the inclination angle θ22 becomes too large (e.g., greater than 10 degrees), the area of ​​the outer surface 23a of the first external connecting wall 23 is reduced, making it difficult for the first external connecting wall 23 to receive the downward molding pressure, and the pressing of the extruded material 20 against the first inner surface 92a is weakened. As described above, by setting the inclination angle θ22, the extruded material 20 can be appropriately pressed against the first inner surface 92a based on the downward molding pressure.

[0058] The end of the second side wall 22 in the mold closing direction, i.e., the corner between the second external connection wall 24 and the second side wall 22, has a complex uneven shape. The second external connection wall 24 is recessed upward on the other widthwise side. The second external connection wall 24 has a base portion 24a on one widthwise side, an offset portion 24c on the other widthwise side that is offset from the base portion 24a toward the mold opening direction (upward during manufacturing), and a step portion 24b in the widthwise center that connects the base portion 24a and the offset portion 24c in the mold opening / closing direction (up and down). The lower end of the second side wall 22 protrudes further toward the mold closing direction (downward during manufacturing) than the offset portion 24c. As a result, the lower end of the second side wall 22, the offset portion 24c, and the step portion 24b form an uneven shape. The lower end of the second side wall 22 is located on the mold opening direction side (upper side during manufacturing) of the outer surface of the base portion 24 a , and does not interfere with the inner surface of the storage portion 92 .

[0059] 6 , in a state in which the extrusion material 20 is accommodated in the accommodation portion 92, a convex rib 92d protrudes from an inner bottom surface 92c of the accommodation portion 92 in the mold opening direction (upward during manufacturing). When the extrusion material 20 is accommodated in the accommodation portion 92, the base portion 24a abuts against the inner bottom surface 92c on the first inner surface 92a side of the convex rib 92d, and the step portion 24b is engaged with the convex rib 92d. The outer surface (exposed surface 21a) of the first side wall 21 is in surface contact with or closely faces the first inner surface 92a of the accommodation portion 92.

[0060] The inner bottom surface 92c is horizontal (perpendicular to the mold opening / closing direction), and the first external connection wall 23 is non-parallel and inclined with respect to the base portion 24a of the second external connection wall 24. Therefore, when the extrusion material 20 is accommodated in the accommodation portion 92 as described above, the first external connection wall 23 is inclined both with respect to the mold opening / closing direction and with respect to the horizontal direction. Specifically, the first external connection wall 23 is inclined toward the mold opening direction from the second side wall 22 toward the first side wall 21.

[0061] The corner portion between the first side wall 21 and the first external connection wall 23 protrudes from the first inner surface 92a in the mold opening direction. The groove 94b is partially closed by the protruding end of the outer surface (exposed surface 21a) of the first side wall 21. The groove 94b is open only in the mold opening direction.

[0062] The first inner surface 92a extends perpendicularly from the inner bottom surface 92c, i.e., in the mold opening / closing direction, and the second side wall 22 is non-parallel and inclined with respect to the first side wall 21. Therefore, when the extruded material 20 is housed in the housing portion 92 as described above, the second side wall 22 is inclined with respect to the mold opening / closing direction. Specifically, the second side wall 22 is inclined so as to move away from the first side wall 21 as it approaches the mold closing direction.

[0063] The outer surface (covered surface 22a) of the second side wall 22 is spaced apart from the second inner surface 92b. The second inner surface 92b extends in the mold opening / closing direction, similar to the first inner surface 92a. Therefore, the space between the outer surface of the second side wall 22 and the second inner surface 92b narrows as it approaches the mold closing direction.

[0064] The step portion 24b is higher than the protruding rib 92d. That is, the offset portion 24c of the second external connecting wall 24 is located closer to the mold opening direction than the protruding end face of the protruding rib 92d. The lower end of the second side wall 22 is located closer to the second inner surface 92b than the protruding rib 92d, while being separated from the second inner surface 92b and forming a space with the second inner surface 92b. The lower end of the second side wall 22 faces a portion of the inner bottom surface 92c closer to the second inner surface 92b than the protruding rib 92d in the mold opening / closing direction. In this way, the space between the outer surface (covering surface 22a) of the second side wall 22 and the second inner surface 92b communicates with the clearance between the lower end of the second side wall 22 and the inner bottom surface 92c and the clearance between the offset portion 24c and the protruding rib 92d, forming a maze-like space overall.

[0065] The upper edge of the second inner surface 92b is lower than the upper edge of the first inner surface 92a. The end of the second inner surface 92b in the mold opening direction is continuous with the outer peripheral edge of the lower molding surface 94a of the base 94 via a tapered surface 94c. A cylindrical insert 97 is erected on the outer peripheral edge of the lower molding surface 94a. A metal nut serving as the joining member 41 is fitted onto the outside of the cylindrical insert 97 (the nut may be threaded or not). Although not shown in detail, a cylindrical insert and joining member 42 are similarly installed on the lower molding surface 94a further to the left of the cutting line on the left side of the paper in Figure 6.

[0066] In this way, because the second inner surface 92b is relatively low and the tapered surface 94c is provided, the protrusion 26 protruding from the first outer connecting wall 23 does not interfere with the second inner surface 92b or the lower molding surface 94a. The space between the outer surface (coating surface 22a) of the second side wall 22 and the second inner surface 92b is widely open in the mold opening direction via the clearance between the tapered surface 94c and the protrusion 26.

[0067] Next, the mold 90 is preheated by the heating unit 9b, and the temperature of the mold 90 rises to a predetermined temperature. Then, a compound of the resin material 50 is placed on the first mold 91. The extruded material 20 and the joining member 41 (and, although not shown in detail, the extruded material 30 and the joining member 42 (see FIG. 2)) are placed on the first mold 91. The compound covers these from above.

[0068] The compound is, for example, SMC. Multiple sheets of the compound are stacked in the space surrounded by the shoulder portion 95. In this embodiment, a larger amount of resin is required around the periphery of the housing portion 92 to form the peripheral wall 52 and the flange wall 53 of the resin material 50, compared to, for example, the central region of the lower molding surface 94a. Therefore, the number of layers of compound stacked around the periphery of the housing portion 92 is greater than in other areas.

[0069] The cylindrical insert 97, the extrusion materials 20 and 30, the joining members 41 and 42, and the compound of the resin material 50 may be manually installed. The manufacturing apparatus 9 may include a manipulator that performs part or all of the installation work.

[0070] Next, referring to Figure 7, the drive unit 9a moves the second mold 99 from the retracted position to the bottom dead center in the mold closing direction. The second mold 99 is, by way of example only, a rectangular parallelepiped. The lower surface of the second mold 99 forms an upper molding surface 99a that faces the lower molding surface 94a of the first mold 91 in the mold opening / closing direction. The side surface of the second mold 99 forms an upper mating surface 99b that extends upward from the periphery of the upper molding surface 99a. In a cross section perpendicular to the mold opening / closing direction, the upper mating surface 99b is similar to the inner surface of the shoulder portion 95 of the first mold 91, but is slightly smaller than this.

[0071] As the second mold 99 moves downward, it fits into the shoulder 95, and the upper mating surface 99b closely faces the lower mating surface 95b with a small mold gap. The second mold 99 is guided by the shoulder 95 and slides in the mold closing direction. The upper molding surface 99a of the second mold 99 comes into contact with the surface layer of the compound of the resin material 50 before the second mold 99 reaches the bottom dead center. FIG. 6 shows this state. The second mold 99 is driven by the drive unit 9a to move further in the mold closing direction, and the compound of the resin material 50 is pressed in the mold closing direction. The compound is softened by the heat of the mold 90 and flows when pressed by the molding pressure applied by the second mold 99.

[0072] 7 shows the bottom dead center state where the second mold 99 is positioned at the bottom dead center. At the bottom dead center, the upper molding surface 99a and the lower molding surface 94a are spaced apart in the mold opening / closing direction. The lower mating surface 95b is a portion of the inner surface of the shoulder 95 that is closer to the mold opening direction than the upper molding surface 99a. The side molding surface 95a is a portion of the inner surface of the shoulder 95 that is closer to the mold closing direction than the upper molding surface 99a. The lower molding surface 94a, the side molding surface 95a, and the upper molding surface 99a define a cavity 90a. The cavity 90a is a space intended to be filled with the resin material 50.

[0073] The space between the second side wall 22 and the second inner surface 92b is intended to be filled with resin material 50, and therefore constitutes part of the cavity 90a. The resin material 50 filled in this space covers the outer surface (coated surface 22a) of the second side wall 22 and forms the peripheral wall 52 (see FIG. 2). On the other hand, the space between the first side wall 21 and the first inner surface 92a is not intended to be filled with resin material 50. The outer surface (exposed surface 21a) of the first side wall 21 is not covered with resin material 50, and it is expected that the aluminum alloy will be exposed in its pure form at least immediately after demolding. Furthermore, the mold gap between the lower mating surface 95b and the upper mating surface 99b is also not intended to be filled with resin material 50.

[0074] By pressing the resin material 50 in the mold closing direction, the molding pressure of the second mold 99 is applied to the outer surface 23 a of the first external connection wall 23 via the resin material 50 .

[0075] Because the outer surface 23a is inclined, the first external connection wall 23 is pushed in the mold closing direction and toward the first inner surface 92a by the wedge action (see the open arrows 1 and 2 in Figure 7). This allows the extruded material 20 to maintain an upright position in the mold opening / closing direction within the accommodating portion 92 and prevent it from tipping toward the second inner surface 92b. When the extruded material 20 stands upright within the accommodating portion 92, an appropriately wide space is secured between the protrusion 26 and the tapered surface 94c. This facilitates the flow of resin material 50 from the region above the lower molding surface 94a into the space between the second side wall 22 and the second inner surface 92b. The reduced flow resistance of this filling path also prevents resin from flowing into small gaps (e.g., mold gaps) that are not intended to be filled with resin.

[0076] The resin material 50 flows in the mold closing direction through the space between the second side wall 22 and the second inner surface 92b. As a result, the molding pressure of the second mold 99 is applied to the outer surface (covered surface 22a) of the second side wall 22 via the resin material 50. Because the outer surface (covered surface 22a) is inclined, the second side wall 22 is pressed in the mold closing direction and toward the first inner surface 92a by the wedge action.

[0077] In this way, the second side wall 22 is also pressed toward the first inner surface 92a together with the first outer connecting wall 23, so that the outer surface (exposed surface 21a) of the first side wall 21 is tightly attached to the first inner surface 92a of the storage portion 92. The space between the first side wall 21 and the first inner surface 92a is closed. This prevents the resin material 50 from unintentionally flowing in, and the exposed surface 21a of the first side wall 21 is not covered with the resin material 50.

[0078] When the resin material 50 flows into the space between the second side wall 22 and the second inner surface 92b, it also fills the space communicating with this space. The resin material 50 covers the periphery of the lower end of the second side wall 22 and also fills the space surrounded by the offset portion 24c and the step portion 24b.

[0079] Furthermore, as the resin material 50 flows into the space between the second side wall 22 and the second inner surface 92b, it covers the periphery of the protrusion 26. The groove 94b, which is closed at the end of the first side wall 21, is open in the mold opening direction and therefore functions as part of the cavity 90a, and the resin material 50 fills this groove 94b, covering the periphery of the corner between the first side wall 21 and the first external connection wall 23. Furthermore, the resin material 50 is filled around the metal nut serving as the joining member 41. In other words, the joining member 41 is integrated with the resin material 50.

[0080] After a predetermined period of time has elapsed with the second mold 99 positioned at the bottom dead center, the resin material 50 hardens. After the resin material 50 hardens, the drive unit 9a moves the second mold 99 in the mold opening direction to the retracted position. As a result, the metal resin composite 100 remains in the first mold 91, as shown in FIG. 8 . The metal resin composite 100 is then removed from the first mold 91.

[0081] After the metal-resin composite body 100 is released from the mold, the metal-resin composite body 100 may be turned upside down as needed, as shown in FIGS. 2 and 3, for use.

[0082] In the metal-resin composite 100 manufactured as described above, the outer surface 23a of the first external connection wall 23 of the extrusion member 20 is coated with the resin material 50. The outer surface 23a slopes toward the outer surface of the resin material 50 as it moves from the second side wall 22 on the outside of the case toward the first side wall 21 on the inside of the case. In this embodiment, the bottom wall 51 is embedded in the first external connection wall 23, and therefore the outer surface of the resin material 50 referred to here specifically refers to the outer bottom surface of the bottom wall 51.

[0083] In the metal-resin composite body 100 having such a structure, as shown in one example of a manufacturing method, a large molding pressure acts on the outer surface 23a coated with the resin material 50 via the resin material 50. The inclination of the outer surface 23a presses the extruded material 20 so that the first side wall 21 is in close contact with the first inner surface 92a of the accommodation portion 92. This prevents the resin material 50 from solidifying on the exposed surface 21a where the aluminum alloy should be exposed, at least immediately after demolding. Therefore, the process of peeling off excess resin material after demolding can be omitted or significantly simplified, improving the production efficiency of the metal-resin composite body 100.

[0084] When the extrusion materials 20, 30 are integrally molded with the resin material 50, due to the low dimensional accuracy of the extrusion materials 20, 30, it is desirable to design the accommodation portions 92, 93 so that the gap between the extrusion materials 20, 30 and the inner surface of the accommodation portions 92, 93 is appropriately large. This gap can cause the need to peel off excess resin material. In this embodiment, the outer surface of the second side wall 22 functions as a covering surface 22a to which the resin material 50 is intentionally fixed. This makes it easier to properly place the extrusion material 20 in the mold 90, reduces the need to peel off excess resin material 50, and improves the bond strength between the extrusion materials 20, 30 via the resin material 50. The improved bond strength allows welding and fastening to be omitted or reduced, further improving the production efficiency of the metal-resin composite 100.

[0085] The covering surface 22a of the second side wall 22 is inclined so as to be away from the first side wall 21. This allows the molding pressure to further press the extruded material 20 toward the first inner surface 92a, further suppressing adhesion of the resin material 50 to the exposed surface 21a.

[0086] The extruded material 20 has a protrusion 26 that protrudes from the covering surface 22 a at the corner between the first external connection wall 23 and the second side wall 22. The resin material 50 solidifies around the protrusion 26, and the extruded material 20 is crimped and joined to the resin material 50. Therefore, the resin material 50 is unlikely to peel off from the extruded material 20.

[0087] The first mold 91 has a groove 94b that is defined by the end of the exposed surface 21a of the first side wall 21 in the mold closing direction and that forms part of the cavity 90a. The resin material 50 that flows into the groove 94b solidifies, causing a thick layer of resin material 50 to be provided at the corner between the first side wall 21 and the first external connection wall 23. The resin material 50 is piled up in a bank shape, which improves the strength of the metal-resin composite 100 and also makes the resin material 50 less likely to peel off from the extruded material 20.

[0088] The extruded material 20 and the resin material 50 form a fitting structure at the end of the second side wall 22 in the mold closing direction. In this regard, in this embodiment, the extruded material 20 has a complex uneven shape at the corner between the second side wall 22 and the second external connection wall 24. The resin material 50 is filled around the area forming this uneven shape through the space between the covering surface 22a and the second inner surface 92b. This forms a fitting structure. As a result, the extruded material 20 and the resin material 50 are crimped together, making it difficult for the resin material 50 to peel off from the extruded material 20.

[0089] Up to this point, the embodiments of the present invention have been described, but the above configurations can be appropriately added to, deleted from, or modified within the scope of the spirit of the present invention.

[0090] In the above embodiment, the protrusion 26 is formed by extending the first external connection wall 23 to the other widthwise side and protrudes from the second side wall 22. The protrusion may be formed by extending another wall or may protrude from another wall. For example, the protrusion may be formed by extending the first side wall 21 or the second side wall 22 in the mold opening direction. The protrusion 26 may be formed by extending the first external connection wall 23 to one widthwise side and protrude from the first side wall 21. Conversely, the protrusion may be omitted. The fitting structure may be omitted.

[0091] In the above embodiment, the first external connecting wall 23 and the second side wall 22 are inclined. The second side wall 22 may extend parallel to the first side wall 21 and / or perpendicular to the second external connecting wall 24.

[0092] The metal-resin composite body 100 can also be applied to vehicle structural members other than the battery case 10. The metal-resin composite body 100 can also be applied to structural members used for purposes other than vehicles.

[0093] The present disclosure may include the following aspects. (Aspect 1) A method for manufacturing a metal resin composite by press-molding a resin material onto a metallic extrusion material, the method comprising: preparing a mold including a first mold forming a housing portion that houses at least a portion of the extrusion material, and a second mold movable in a mold closing direction and a mold opening direction relative to the first mold; housing the extrusion material in the housing portion and arranging the resin material in the first mold; moving the second mold in the mold closing direction to form a cavity defined by the extrusion material and the mold, and pressurizing the resin material to fill the cavity; wherein the extrusion material has: a first side wall that forms an exposed surface where the metal is exposed and that is to face closely to a first inner surface of the housing portion; a second side wall that forms a coated surface that is coated with the resin material and that defines the cavity together with a second inner surface of the housing portion; and an external connecting wall that forms an outer surface that is coated with the resin material and that connects end portions of the first side wall and the second side wall on the mold opening direction side when the extrusion material is housed in the housing portion. A method for manufacturing a metal resin composite, wherein the outer surface is inclined from the second side wall toward the first side wall in the mold opening direction in the housed state. (Aspect 2) A method for manufacturing a metal resin composite according to Aspect 1, wherein the covered surface is inclined in the housed state so as to move away from the first side wall in the mold closing direction. (Aspect 3) A method for manufacturing a metal resin composite according to Aspect 1 or 2, wherein the extruded material further has a protrusion that protrudes from the covered surface at a corner portion between the external connection wall and the second side wall. (Aspect 4) A method for manufacturing a metal resin composite according to any of Aspects 1 to 3, wherein the first mold has a groove that is defined by an end portion of the exposed surface of the first side wall on the mold closing direction side and that forms part of the cavity. (Aspect 5) A method for manufacturing a metal resin composite according to any of Aspects 1 to 4, wherein the extruded material and the resin material form a fitting portion at the end portion of the second side wall on the mold closing direction side.(Aspect 6) A metal-resin composite formed by integrating a resin material with a metal extrusion material by press molding, wherein the extrusion material has: a first side wall forming an exposed surface where the metal is exposed; a second side wall forming a covered surface that is covered with the resin material; and an external connecting wall connecting ends of the first side wall and the second side wall and forming an outer surface that is covered with the resin material, wherein the outer surface of the external connecting wall slopes from the second side wall toward the first side wall toward the outer surface of the resin material.

[0094] This application claims priority from Japanese Patent Application No. 2023-119921, filed on July 24, 2023. Japanese Patent Application No. 2023-119921 is incorporated herein by reference.

[0095] DESCRIPTION OF SYMBOLS 1 Automobile 2 Battery 3 Front portion of vehicle 4 Center portion of vehicle body 5 Vehicle compartment 9 Manufacturing device 9a Drive unit 9b Heating unit 10 Battery case 11 Frame 12, 13 Side member 14 Front member 15 Rear member 16 Cross member 20 Extruded material 21 First side wall 21a Exposed surface 22 Second side wall 22a Covered surface 23 First outer connecting wall 23a Outer surface 24 Second outer connecting wall 24a Base portion 24b Step portion 24c Offset portion 25a, 25b Inner connecting wall 26 Protrusion 30 Extruded material 31 First side wall 32 Second side wall 33 First outer connecting wall 34 Second outer connecting wall 35a, 35b Inner connecting wall 36a, 36b Extended side walls 41, 42 Joining member 50 Resin material 51 Bottom wall 52 Surrounding wall 53 Flange wall 54 Ridge portion 90 Mold 90a Cavity 91 First mold 92 Storage portion 92a First inner surface 92b Second inner surface 92c Inner bottom surface 92d Convex rib 93 Storage portion 94 Base 94a Lower molding surface 94b Groove 94c Tapered surface 95 Shoulder 95a Side molding surface 95b Lower mating surface 97 Cylindrical insert 99 Second mold 99a Upper molding surface 99b Upper mating surface 100 Metal-resin composite θ22, θ23 Inclination angle

Claims

1. A manufacturing method of a metal resin composite material by press molding a resin material onto a metallic extrusion material, comprising: preparing a mold including a first mold forming a housing portion for housing at least a portion of the extrusion material, and a second mold movable in a mold closing direction and a mold opening direction relative to the first mold; housing the extrusion material in the housing portion and arranging the resin material into the first mold; moving the second mold in the mold closing direction to form a cavity defined by the extrusion material and the mold, and pressurizing the resin material to fill the cavity; wherein the extrusion material forms an exposed surface on which the metal is exposed, and a first side wall that should closely face a first inner surface of the housing portion in a housing state in which the extrusion material is housed in the housing portion; and a second side wall that forms a covered surface covered with the resin material and defines the cavity together with the second inner surface of the housing portion in the housing state. an external connecting wall that forms an outer surface covered with the resin material and connects ends of the first side wall and the second side wall in the mold opening direction in the accommodated state, wherein the outer surface is inclined from the second side wall to the first side wall in the mold opening direction in the accommodated state.

2. The method for producing a metal resin composite body according to claim 1, wherein the covering surface is inclined so as to move away from the first side wall in the mold closing direction in the housed state.

3. The method for producing a metal-resin composite body according to claim 1 or 2, wherein the extrusion material further has a protrusion that protrudes toward the coated surface at a corner portion between the external connection wall and the second side wall.

4. A method for manufacturing a metal-resin composite as described in claim 1 or 2, wherein the first mold forms a groove that is defined by the end of the exposed surface of the first side wall in the mold closing direction and that constitutes part of the cavity.

5. The method for manufacturing a metal-resin composite body according to claim 1 or 2, wherein the extrusion material and the resin material form an interlocking structure at an end of the second side wall facing the mold closing direction.

6. A metal-resin composite material formed by integrating a resin material with a metallic extrusion material by press molding, wherein the extrusion material has: a first side wall forming an exposed surface where the metal is exposed; a second side wall forming a covered surface that is covered with the resin material; and an external connecting wall connecting ends of the first side wall and the second side wall to form an outer surface that is covered with the resin material, wherein the outer surface of the external connecting wall slopes from the second side wall toward the first side wall toward the outer surface of the resin material.

Images