Metal-resin composite body and method for producing same

Abstract

An extruded material (20) comprises: a first side wall (21) that forms an exposure surface (21a) in which a metal is exposed and that, in an accommodated state in which the extruded material (20) is accommodated in an accommodation part (92) of a first mold (91), is to closely face a first inner side surface (92a) of the accommodation part (92); a second side wall (22) that forms a covered surface (22a) which is covered with a resin material (50) and that defines, together with a second inner side surface (92b) of the accommodation part (92), a cavity (90a) which is filled with the resin material (50); and a hook part (29) that protrudes from a mold opening direction-side end part of the first side wall (21) and that is locked to the first mold (10) in the accommodated state.

Description

Metal-resin composite and method of manufacturing the same

[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 an extruded metal material, the method comprising the steps of: preparing a mold including a first mold forming a housing portion for housing at least a portion of the extruded material; and a second mold movable in a mold closing direction and a mold opening direction relative to the first mold; housing the extruded material in the housing portion; placing the resin material in the first mold; moving the second mold in the mold closing direction to form a cavity defined by the extruded material and the mold; and pressurizing the resin material to close the cavity. and filling the extruded material into a cavity, wherein the extruded material forms an exposed surface on which the metal is exposed, and in a contained state where the extruded material is contained in the containing section, the extruded material has a first side wall that is to closely face a first inner surface of the containing section, a covered surface that is covered with the resin material, and a second side wall that, in the contained state, defines the cavity together with a second inner surface of the containing section, and a hook portion that protrudes from an end of the first side wall on the mold opening direction side and is engaged with the first mold in the contained state.

[0008] According to the above configuration, when the resin material is pressurized, the molding pressure acts on the extruded material via the resin material. The hooks engage with the first mold, allowing the extruded material to maintain a position in which the exposed surface of the first side wall is close to the first inner surface of the housing. In other words, the gap between the first side wall and the first inner surface can be continuously filled while the resin material is being filled into the cavity. This prevents the resin material from solidifying on the exposed surface, ensuring that the metal is properly exposed 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, properly coating the second side wall with the resin material.

[0009] The first mold may form a groove defined by an end of an outer surface of the hook portion and constituting a part of the cavity.

[0010] According to the above configuration, a thick resin material can be provided around the hook portion, making it difficult for the resin material to peel off from the extruded material.

[0011] 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.

[0012] 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.

[0013] The extrusion material may further have an external connecting wall that connects the ends of the first side wall and the second side wall in the mold opening direction when in the stored state, and a protrusion that protrudes toward the coated surface at the corner between the external connecting wall and the second side wall.

[0014] 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.

[0015] Another aspect of the present disclosure provides a metal-resin composite formed by integrating a resin material with a metal extrusion by press molding, wherein the extrusion has a first side wall that forms an exposed surface that exposes the metal, a second side wall that forms a covered surface that is covered with the resin material, and a hook portion that protrudes from an end of the exposed surface of the first side wall.

[0016] According to the above configuration, the hook portion protruding from the end of the exposed surface can be used to tightly attach the first side wall of the extruded material to a 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 that should be coated with the resin material. This provides a metal-resin composite with high production efficiency.

[0017] 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.

[0018] 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 the metal resin composite according to the first embodiment. FIG. 3 is a perspective view of the automobile battery case cut along line III-III in FIG. 2. FIG. 4 is a 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 the extruded material. FIG. 6 is a sectional view of the extruded material and a mold in a state where the resin material has been placed. FIG. 7 is a sectional view of the extruded material and a mold in a state where the resin material has been hot-pressed. FIG. 8 is a sectional view of the second embodiment, corresponding to FIG. 3. FIG. 5 is a sectional view of the second embodiment, corresponding to FIG. 6. FIG. 8 is a sectional view of the second embodiment, corresponding to FIG.

[0019] 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.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] Referring to FIG. 2 , battery case 10 includes frame 11 in which a plurality of extrusion members 20 and 30 are arranged in a frame shape, and resin material 50 molded integrally with frame 11 .

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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 .

[0045] 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.

[0046] 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.

[0047] 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. 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. A slit 94d is formed in the base 94 by recessing the inner bottom surface of this groove 94b in the mold opening direction.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] In this embodiment, as a mere example, the first outer connecting wall 23, the second outer connecting wall 24, and the inner connecting walls 25a and 25b are parallel to one another. The first side wall 21 and the second side wall 22 are perpendicular to the first outer connecting wall 23 and parallel to one another. However, these walls may have any shape that does not affect demolding after molding, and are not necessarily limited to being parallel or perpendicular.

[0054] A hook portion 29 is provided at the end of the first side wall 21 in the mold opening direction, in other words, at the corner between the first external connection wall 23 and the first side wall 21. The hook portion 29 protrudes from this end of the first side wall 21. The hook portion 29 has an L-shaped cross section and includes a protruding portion 29a and a bent portion 29b. The protruding portion 29a protrudes from the end of the exposed surface 21a of the first side wall 21 toward one side in the width direction. In other words, the first external connection wall 23 is extended toward one side in the width direction relative to the first side wall 21. The bent portion 29b protrudes from the tip of the protruding portion 29a in the mold closing direction by being bent.

[0055] 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 .

[0056] 6, when the extrusion material 20 is inserted into the accommodating portion 92, the bent portion 29b of the hook 29 is inserted into the slit 94d from above. The lower surface or inner surface (i.e., the surface facing the mold closing direction) of the protruding portion 29a of the hook 29 is supported by the inner bottom surface of the groove 94b. The hook 29 is disposed on the other widthwise side of the groove 94b. The tip surface of the hook 29 faces into the groove 94b. The remaining portion of the groove 94b not filled with the hook 29 is defined on the other widthwise side by the end surface of the hook 29, while remaining open on the upper side (the mold opening direction side).

[0057] A protruding rib 92d protrudes in the mold opening direction (upward during manufacturing) from the inner bottom surface 92c of the accommodation portion 92. 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 protruding rib 92d, and the step portion 24b is engaged with the protruding rib 92d.

[0058] The outer surface (exposed surface 21a) of the first side wall 21 is in surface contact with or closely faces a first inner surface 92a of the accommodation portion 92 formed by the base 94. The first inner surface 92a extends perpendicularly from the inner bottom surface 92c, i.e., in the mold opening / closing direction.

[0059] 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.

[0060] 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.

[0061] 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.

[0062] In this way, the second inner surface 92 b is relatively low, and the tapered surface 94 c is provided, so that the space between the outer surface (covered surface 22 a) of the second side wall 22 and the second inner surface 92 b is widely open in the mold opening direction via a clearance between the tapered surface 94 c and the extrusion material 20.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] As the resin material 50 is pressed 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 .

[0071] In this embodiment, the hook portion 29 is engaged with the first mold 91. This maintains the extruded material 20 standing upright in the mold opening / closing direction within the storage portion 92, preventing it from tipping toward the second inner surface 92b. When the extruded material 20 stands upright within the storage portion 92, an appropriately wide space is secured between the extruded material 20 and the tapered surface 94c. This makes it easier for the resin material 50 to flow from the region above the lower molding surface 94a into the space between the second side wall 22 and the second inner surface 92b. Because the flow resistance of this filling path is reduced, it is also possible to prevent the resin material 50 from flowing into small gaps (e.g., mold gaps) that are not intended to be filled with resin.

[0072] 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 one side in the width direction on the outer surface (covered surface 22a) of the second side wall 22 via the resin material 50. As a result, the extruded material 20 is pressed toward the first inner surface 92a.

[0073] In this way, by pressing the second side wall 22 toward the first inner surface 92a, the outer surface (exposed surface 21a) of the first side wall 21 is brought into close contact with 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 makes it possible to prevent 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.

[0074] 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.

[0075] The groove 94b is open in the mold opening direction and functions as part of the cavity 90a, and the resin material 50 is filled into the groove 94b to cover the periphery of the hook portion 29. 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.

[0076] While the groove 94b functions as part of the cavity 90a, the space between the exposed surface 21a and the first inner surface 92a is not intended for the resin material 50 to flow into. The two can communicate with each other through the space between the hook 29 and the base 94. However, because the space is labyrinthine due to the engagement between the hook 29 and the base 94, the resin material 50 is less likely to enter through the groove 94b. Furthermore, the molding pressure applied to the first outer connection wall 23 presses the hook 29 in the mold closing direction. This presses the bent portion 29b of the hook 29 against the inner surface of the slit 94d and the protruding portion 29a of the hook 29 against the inner bottom surface of the groove 94b. This closes the space between the hook 29 and the base 94, preventing the resin material in the groove 94b from entering between the exposed surface 21a and the first inner surface 92a.

[0077] 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.

[0078] 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.

[0079] In the metal-resin composite body 100 manufactured as described above, the extruded material 20 has a hook portion 29 protruding from the end of the exposed surface 21 a of the first side wall 21. As shown in one example of the manufacturing method, the hook portion 29 is used to ensure that the first side wall 21 of the extruded material 20 adheres closely to the first inner surface 92 a of the accommodation portion 92, thereby maintaining the upright posture of the extruded material 20. This prevents the resin material 50 from solidifying on the exposed surface 21 a where the aluminum alloy should be exposed, at least immediately after demolding. This makes it possible to omit or significantly simplify the process of removing excess resin material after demolding, improving the production efficiency of the metal-resin composite body 100.

[0080] 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.

[0081] The first mold 91 has a groove 94b that is defined by the hook portion 29 and that forms part of the cavity 90a. The resin material 50 that flows into the groove 94b solidifies, causing a thick layer of the resin material 50 to be provided around the hook portion 29. By piling up the resin material 50 in a bank shape, the strength of the metal-resin composite 100 is improved, and the resin material 50 is also less likely to peel off from the extruded material 20.

[0082] 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.

[0083] Next, the second embodiment will be described with reference to FIGS. 9 to 12, focusing on the differences from the first embodiment.

[0084] In the extrusion material 20 according to this embodiment, 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 that protrudes 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.

[0085] Similar to the first embodiment, the upper edge of the second inner surface 92b is relatively low and has a tapered surface 94c. Therefore, when the extruded material 20 is housed, the protrusion 26 does not interfere with the second inner surface 92b or the lower molding surface 94a. The space between the outer surface (covering surface 22a) of the second side wall 22 and the second inner surface 92b is widely open in the opening direction via a clearance between the tapered surface 94c and the protrusion 26. When the resin material 50 is pressurized, the resin material 50 covers the periphery of the protrusion 26 as it flows into the space between the second side wall 22 and the second inner surface 92b. When molding pressure is applied to the inclined surface of the protrusion 26, the extruded material 20 is pushed toward the first inner surface 92a by a wedge action. This makes it easier to close the gap between the exposed surface 21a and the first inner surface 92a.

[0086] The resin material 50 solidifies around the protrusions 26, and the extruded member 20 is crimped and joined to the resin material 50. Therefore, the resin material 50 becomes even more difficult to peel off from the extruded member 20.

[0087] 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.

[0088] 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.

[0089] 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.

[0090] 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, 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 forms an exposed surface that exposes the metal, and a first side wall that is to face closely to a first inner surface of the housing portion in an accommodated state where the extrusion material is accommodated in the housing portion; and a second side wall that forms a covered surface that is covered with the resin material and defines the cavity together with a second inner surface of the housing portion in the accommodated state. a hook portion protruding from an end of the first side wall in the mold opening direction and engaging with the first mold in the accommodated state. (Aspect 2) The method for manufacturing a metal resin composite according to Aspect 1, wherein the first mold forms a groove defined by an end of the outer surface of the hook portion and constituting part of the cavity. (Aspect 3) The method for manufacturing a metal resin composite according to Aspect 1 or 2, wherein the extruded material and the resin material form a fitting structure at an end of the second side wall in the mold closing direction. (Aspect 4) The method for manufacturing a metal resin composite according to any of Aspects 1 to 3, wherein the extruded material further has an external connection wall connecting the ends of the first side wall and the second side wall in the mold opening direction together in the accommodated state, and a protrusion protruding from the covered surface at a corner portion between the external connection wall and the second side wall. (Aspect 5) A metal-resin composite formed by integrating a resin material with a metal extrusion by press molding, wherein the extrusion has: a first side wall that forms an exposed surface that exposes the metal; a second side wall that forms a covered surface that is covered with the resin material; and a hook portion that protrudes from an end of the exposed surface of the first side wall.

[0091] This application claims priority from Japanese Patent Application No. 2023-123687, filed on July 28, 2023. Japanese Patent Application No. 2023-123687 is incorporated herein by reference.

[0092] REFERENCE SIGNS LIST 1 Automobile 2 Battery 3 Vehicle front portion 4 Vehicle body center portion 5 Vehicle compartment 9 Manufacturing device 9a Drive portion 9b Heating portion 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 29 Hook portion 29a Protruding portion 29b Bent portion 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 wall 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 side surface 92b Second inner side surface 92c Inner bottom surface 92d Convex rib 93 Storage portion 94 Base 94a Lower molding surface 94b Groove 94c Tapered surface 94d Slit 95 Shoulder portion 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

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 die including a first die forming a housing portion for housing at least a portion of the extrusion material, and a second die movable in a die closing direction and a die opening direction relative to the first die; housing the extrusion material in the housing portion and arranging the resin material into the first die; moving the second die in the die closing direction to form a cavity defined by the extrusion material and the die, 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; 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; and a hook portion that protrudes from an end of the first side wall on the die opening direction side and is engaged with the first die in the housing state. The method for producing a metal-resin composite body comprising the steps of:

2. The method for producing a metal-resin composite body according to claim 1, wherein the first mold forms a groove that is defined by an end of the outer surface of the hook portion and that constitutes a part of the cavity.

3. 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.

4. A method for producing a metal resin composite as described in claim 1 or 2, wherein the extrusion material further has an external connecting wall that connects the ends of the first side wall and the second side wall in the mold opening direction in the accommodated state, and a protrusion that protrudes toward the coated surface at a corner portion between the external connecting wall and the second side wall.

5. A metal-resin composite body formed by integrating a resin material with a metallic extrusion material by press molding, the extrusion material having a first side wall forming an exposed surface that exposes the metal, a second side wall forming a covered surface that is covered with the resin material, and a hook portion protruding from an end of the exposed surface of the first side wall.

Images