Insert molded body, battery tray, protective cover for battery tray, inverter box, and method for producing insert molded body

Abstract

This insert molded body (1) has a resin component (10) and a metal component (20). The resin component (10) has a thicker section (11) and a thinner section (12) that is thinner than the thicker section (11). At least a portion of the metal component (20) is disposed on the outer surface of the resin component (10) along the thicker section (11) or the thinner section (12). The metal component (20) has a direction-changing section (23) in which the direction of extension on the outer surface is changed. The resin component (10) and the metal component (20) are fixed to one another in the direction-changing section (23).

Description

Insert molded body, battery tray, protective cover for battery tray and inverter box, and method for manufacturing insert molded body

[0001] The present disclosure relates to an insert-molded article, a battery tray, a protective cover for a battery tray and an inverter box, and a method for manufacturing an insert-molded article.

[0002] An insert-molded product is a molded product manufactured by placing an insert such as a metal part in a mold and molding it, combining a resin material with a metal material. Because insert-molded products can be manufactured into parts with desired structures through a simple process, they are used for a variety of parts, including automotive parts. Patent Document 1 discloses an insert molding method in which a metal conductive insert part is set in a mold and a thermoplastic resin is injected to form an integral mold. Patent Document 2 discloses a method for manufacturing an automotive seatback frame, which includes cold-press molding a fiber-reinforced composite material into the shape of a seatback frame body, and welding a metal plate to the seatback frame body by insert molding during the molding process.

[0003] International Publication No. WO 2015 / 29482 International Publication No. WO 2013 / 21482

[0004] For example, an insert-molded product in which a metal part is disposed on a resin part can be used as an impact detection sensor. However, in such an insert-molded product in which a metal part is disposed on a resin part, the metal part may lift off the resin part during molding. If the metal part lifts off, there is a risk that the dimensions of the molded product will be distorted or the performance of the part will be degraded.

[0005] The present disclosure relates to an insert-molded article in which floating of a metal part is reduced, and a method for manufacturing the insert-molded article.

[0006] An insert molded body according to one embodiment of the present disclosure is an insert molded body having a resin part and a metal part, wherein the resin part has a thickness deviation portion and a thin-walled portion that is thinner than the thickness deviation portion, at least a portion of the metal part is disposed on the outer surface of the resin part along the thickness deviation portion or the thin-walled portion, the metal part has a turning portion whose extending direction on the outer surface is changed, and the resin part and the metal part are fixed to each other at the turning portion.

[0007] A manufacturing method of an insert molded body according to one embodiment of the present disclosure is a manufacturing method of an insert molded body having a resin part and a metal part, wherein the resin part has a thickness deviation portion and a thin-walled portion that is thinner than the thickness deviation portion, at least a portion of the metal part is disposed on an outer surface of the resin part along the thickness deviation portion or the thin-walled portion, and the metal part has a turning portion whose extending direction on the outer surface is changed, and the method includes a step of fixing the resin part and the metal part to each other at the turning portion.

[0008] According to the insert molded article and the method for manufacturing an insert molded article of the present disclosure, it is possible to provide an insert molded article in which floating of the metal part is reduced.

[0009] FIG. 1 is a plan view showing an insert-molded body according to a first embodiment of the present disclosure. FIG. 2 is a cross-sectional view taken along the line A-A in FIG. 1. FIG. 3 is a cross-sectional view taken along the line B-B in FIG. 1. FIG. 4 is a cross-sectional view showing a portion of a resin part that does not have a resin layer with a different fiber volume fraction. FIG. 5 is a cross-sectional view showing an insert-molded body that has a resin layer with a different fiber volume fraction. FIG. 6 is a cross-sectional view of a molding die for producing an insert-molded body according to an embodiment of the present disclosure. FIG. 7 is a plan view showing an insert-molded body according to a second embodiment of the present disclosure. FIG. 8 is a plan view showing an insert-molded body according to a third embodiment of the present disclosure. FIG. 9A is a cross-sectional view of a resin part for explaining flatness Fa. FIG. 9B is a cross-sectional view of a resin part for explaining flatness Fa. FIG. 10 is a cross-sectional view of a resin part for explaining the difference in thickness h between an uneven-walled portion and a thin-walled portion. FIG. 11 is a schematic diagram showing a protective cover for a battery tray installed in a vehicle. FIG. 12 is a cross-sectional view of an insert-molded body used in an inverter box.

[0010] First, an embodiment of the present disclosure will be described. An insert-molded article according to one embodiment of the present disclosure includes: (1) an insert-molded article having a resin part and a metal part, wherein the resin part has a thickness deviation portion and a thin-walled portion that is thinner than the thickness deviation portion, at least a portion of the metal part is disposed on an outer surface of the resin part along the thickness deviation portion or the thin-walled portion, the metal part has a direction-changing portion that changes the direction of extension on the outer surface, and the resin part and the metal part are fixed to each other at the direction-changing portion.

[0011] When producing an insert molded product in which a metal part is placed on a resin part, the metal part may lift up in the thickness direction (the direction perpendicular to the outer surface of the resin part). Furthermore, when the metal part cools, the direction change part is subject to contraction forces with different vectors, making the direction change part particularly prone to lifting up. In the insert molded product according to this embodiment, the direction change part of the metal part is fixed to the resin part, reducing the lifting of the metal part.

[0012] (2) In the above (1), at least a portion of the metal part may be disposed along the thin-walled portion.

[0013] In the insert molded article according to this embodiment, a metal part is placed on the top of a convex part provided in a mold to form a thin-walled part during molding. For example, if a metal part is placed along the convex part (top) of the lower mold during insert molding, and then a resin material is layered on top and press-molded, the metal part will be placed along the bottom of the thin-walled part (concave part) when the insert molded article is completed.

[0014] (3) In the above (1), at least a portion of the metal part may be disposed along the uneven thickness portion.

[0015] In the insert-molded article according to this embodiment, a metal part is placed in a groove provided in a mold to form a thickness-uneven portion during molding. This facilitates positioning of the metal part, making molding easier. For example, if a metal part is placed along the recess (groove) of the lower mold during insert molding, and then a resin material is layered on top and press-molded, the metal part will be positioned along the apex of the thickness-uneven portion (protrusion) when the insert-molded article is formed.

[0016] (4) In any of (1) to (3) above, the metal part may have a first portion extending in a first in-plane direction and a second portion extending in a second in-plane direction different from the first in-plane direction, and the deflection portion may connect the first portion and the second portion.

[0017] The deflection portion connecting the first and second portions extending in different directions is particularly prone to lifting up. According to the insert molding product of this embodiment, such deflection portion is fixed, so that lifting up can be effectively reduced.

[0018] (5) In the above (4), the first in-plane direction and the second in-plane direction may be perpendicular to each other.

[0019] The insert molded article according to this embodiment has a shape that is bent vertically at the direction change portion, and the effect of reducing lifting by fixing the direction change portion is particularly high. In addition, there is a high degree of freedom in the arrangement of metal parts.

[0020] (6) In any one of the above (1) to (5), the resin part may be formed of a fiber-reinforced composite material, and a fiber volume fraction Vfa of the uneven thickness portion may be smaller than a fiber volume fraction Vfb of the thin thickness portion.

[0021] The insert molded article according to this embodiment can be manufactured by a simple method, since a flat plate-shaped resin material can be used before molding.

[0022] (7) In any of the above (1) to (6), the resin part may be formed of a fiber-reinforced composite material, the resin part may have a first resin layer and a second resin layer disposed closer to the metal part than the first resin layer, and a fiber volume fraction Vf1 of the first resin layer may be greater than a fiber volume fraction Vf2 of the second resin layer.

[0023] Insert molded articles with uneven thickness and thin-walled sections are prone to warping during cooling in the molding process. On the other hand, when an insert molded article has resin layers with different fiber volume fractions, the shrinkage rate varies depending on the fiber volume fraction, and the difference in the shrinkage rate of each resin layer causes a warping force during cooling. The insert molded article according to this embodiment stacks first and second resin layers with different shrinkage rates in a predetermined order, thereby offsetting the warping caused by the shape and the warping caused by the difference in the shrinkage rates of the resin layers, thereby suppressing overall warping.

[0024] (8) In any one of the above (1) to (7), the resin part may be formed of a fiber-reinforced composite material, and the weight-average fiber length of the reinforcing fibers contained in the resin part may be 100 mm or less.

[0025] In the insert molded article according to this embodiment, the length of the fibers contained in the resin part is short, which can reduce warping of the resin part that occurs during cooling in the molding process.

[0026] (9) In the above (2) or (3), when the direction perpendicular to the outer surface of the resin part is defined as the thickness direction, the difference in thickness between the uneven thickness portion and the thin-walled portion may be equal to or greater than the thickness of the metal part.

[0027] When at least a portion of the metal component is positioned along the thin-walled portion, the insert-molded product according to this embodiment is less likely to shift when the difference in thickness between the uneven thickness portion and the thin-walled portion is equal to or greater than the thickness of the metal component. When at least a portion of the metal component is positioned along the uneven thickness portion, the insert-molded product according to this embodiment has a groove depth in the mold for forming the uneven thickness portion that is at least twice the thickness of the metal component, making it easier to position and mold the metal component. As described above, for example, during insert molding, if a metal component is positioned along the recess (groove) of the lower mold and then a resin material is layered on top and press-molded, the resulting insert-molded product will be positioned along the apex of the uneven thickness portion (protrusion). If the difference in thickness between the uneven thickness portion and the thin-walled portion is designed to be equal to or greater than the thickness of the metal component, the metal component will be less likely to shift from the recess (groove) of the lower mold during molding.

[0028] (10) In any one of the above (1) to (9), the uneven thickness portions and the thin-walled portions may be positioned alternately in a cross section perpendicular to the outer surface of the resin part.

[0029] According to the insert molded product of this embodiment, the metal part can be evenly arranged on the resin part.

[0030] (11) In the above (10), at least a portion of the metal part may be arranged along the uneven thickness portion or the thin-walled portion, and the relationship between the flatness Fa of the resin part and the difference in thickness h between the uneven thickness portion and the thin-walled portion may be 0 < Fa / h < 1.3.

[0031] According to the insert molded product of this embodiment, it is possible to further reduce the floating of the metal part from the resin part, and it becomes easier to combine it with other parts.

[0032] A battery tray or a protective cover for a battery tray according to one embodiment of the present disclosure includes: (12) the insert molding according to any one of (1) to (11) above, wherein the metal part is an electrical circuit for impact detection.

[0033] The battery tray or battery tray protective cover according to this embodiment can detect impact and prevent the battery from catching fire or the like.

[0034] An inverter box according to an embodiment of the present disclosure includes: (13) the insert-molded article according to any one of (1) to (11) above, wherein the metal part is an electric circuit.

[0035] In the inverter box according to this embodiment, the electrical circuit and the resin parts are fixed together, and the floating of the electrical circuit is reduced.

[0036] A manufacturing method of an insert molded body according to one embodiment of the present disclosure is (14) a manufacturing method of an insert molded body having a resin part and a metal part, wherein the resin part has a thickness deviation portion and a thin-walled portion that is thinner than the thickness deviation portion, and at least a portion of the metal part is disposed on an outer surface of the resin part along the thickness deviation portion or the thin-walled portion, and the metal part has a turning portion whose extending direction on the outer surface is changed, and the method includes a step of fixing the resin part and the metal part to each other at the turning portion.

[0037] According to the manufacturing method of the insert molded article according to this embodiment, by fixing the direction change portion of the metal part, it is possible to provide an insert molded article in which the floating of the metal part is reduced.

[0038] (15) In the above (14), the insert-molded body may further have a sealing layer that seals the metal part, and the method may include a step of molding the sealing layer together with the resin part and the metal part.

[0039] According to the method for manufacturing an insert molded article according to this embodiment, it is possible to protect the insert molded article and provide it with insulating properties without requiring a separate process.

[0040] Hereinafter, an insert molded article and a method for manufacturing an insert molded article according to an embodiment of the present disclosure will be described with reference to the drawings, but the present invention is not limited to these examples. The dimensions and positions of each component in the drawings are schematic and are not intended to limit the dimensions and positions of the components in an actual product.

[0041] [Insert Molded Product] Fig. 1 is a plan view showing an insert molded product 1 according to a first embodiment of the present disclosure. The insert molded product 1 according to this embodiment can be used, for example, as an impact detection sensor disposed on the bottom of a vehicle. As shown in Fig. 1, the insert molded product 1 includes a resin part 10 and a metal part 20, with the metal part 20 disposed on the outer surface of the resin part 10. Fig. 2 is a cross-sectional view taken along line A-A in Fig. 1. Fig. 3 is a cross-sectional view taken along line B-B in Fig. 1.

[0042] (Resin Part) The resin part 10 has a generally flat plate shape. As shown in FIG. 2 , the resin part 10 has a thickness deviation portion 11 and a thin-walled portion 12 that is thinner than the thickness deviation portion 11. One main surface of the resin part 10 (the upper surface in FIG. 2 ) has a convex portion corresponding to the thickness deviation portion 11, and the other main surface (the lower surface in FIG. 2 ) is flat. In the present disclosure, the thickness deviation portion 11 refers to a portion that varies in thickness relative to the entire resin part 10, and the thickness deviation portion 11 itself may be uniform. When the metal part 20 is arranged along the thickness deviation portion 11, it is preferable that the outer surface of the thickness deviation portion 11 on which the metal part 20 is arranged is flat.

[0043] The resin material constituting the resin part 10 is not particularly limited, and various raw materials can be appropriately selected depending on the application of the insert-molded body 1. For example, when the insert-molded body 1 is a vehicle part, the resin part 10 may be made of a fiber-reinforced composite material from the viewpoint of improving strength and reducing weight. Either carbon fiber or glass fiber may be used as the reinforcing fiber, or both may be used in combination. Either a thermosetting resin or a thermoplastic resin may be used as the resin, and it is preferable to use a thermoplastic resin.

[0044] Examples of thermoplastic resins include vinyl chloride resins, vinylidene chloride resins, vinyl acetate resins, polyvinyl alcohol resins, polystyrene resins, acrylonitrile-styrene resins (AS resins), acrylonitrile-butadiene-styrene resins (ABS resins), acrylic resins, methacrylic resins, polyethylene resins, polypropylene resins, various thermoplastic polyamide resins, polyacetal resins, polycarbonate resins, polyethylene terephthalate resins, polyethylene naphthalate resins, polybutylene naphthalate resins, polybutylene terephthalate resins, polyarylate resins, polyphenylene ether resins, polyphenylene sulfide resins, polysulfone resins, polyether sulfone resins, polyether ether ketone resins, and polylactic acid resins.

[0045] The thermoplastic resin may be a crystalline resin or an amorphous resin. In the case of a crystalline resin, specific examples of preferred crystalline resins include polyamide resins such as nylon 6, polyethylene terephthalate resins, polybutylene terephthalate resins, polyethylene resins, polypropylene resins, polyacetal resins, and polyphenylene sulfide resins. Among these, polyamide resins, polybutylene terephthalate resins, and polyphenylene sulfide resins are preferably used because of their excellent heat resistance and mechanical strength.

[0046] The thickness of the resin part 10 is not particularly limited, but is, for example, 0.5 mm to 10.0 mm, and preferably 1.0 mm to 8.0 mm. The thickness of the resin part 10 here refers to the thickness of the thickest part, more specifically, the maximum thickness of the uneven thickness portion 11.

[0047] (Metal Part) The metal part 20 is a metal plate arranged on the outer surface of the resin part 10. As shown in Fig. 1, the metal part 20 is arranged in a bellows shape on the main surface of the resin part 10 and is configured to widely cover the main surface of the resin part 10. At least a portion of the metal part 20 is arranged on the outer surface of the resin part 10 along the thickness deviation portion 11 or the thin-walled portion 12. In the insert-molded product 1 of Fig. 1, the metal part 20 is arranged along the thickness deviation portion 11 of the resin part 10, more specifically, on the thickness deviation portion 11.

[0048] 1 , the metal part 20 has a turning portion 23 in which the direction of extension on the outer surface is changed. More specifically, the metal part 20 has a first portion 21 extending in the up-down direction of the paper (hereinafter referred to as the first in-plane direction) and a second portion 22 extending in the left-right direction of the paper (hereinafter referred to as the second in-plane direction), and the first portion 21 and the second portion 22 are connected at the turning portion 23. In this embodiment, the rectangular area in which the extended portion of the first portion 21 and the extended portion of the second portion 22 overlap can be considered to be the turning portion 23.

[0049] There are no particular limitations on the metal material that constitutes the metal component 20, and various metals or alloys can be used depending on the required properties. Examples of metal materials include copper, aluminum, iron, chromium, nickel, manganese, and alloys thereof.

[0050] The shape of the metal component 20 is not limited to a plate shape and can be changed as appropriate depending on the application and configuration. Specifically, the metal component 20 may be a metal wire having a substantially circular cross section, or may be a bundle of stacked or integrated metal wires.

[0051] The thickness of the metal part 20 is not particularly limited and can be changed as appropriate depending on the application and configuration. The thickness of the metal part 20 may be, for example, 0.01 mm to 10 mm, 0.05 mm to 1.0 mm, or 0.10 mm to 0.50 mm. When the metal part 20 is a metal wire, the maximum diameter along the thickness direction of the cross section of the metal wire is considered to be the thickness.

[0052] (Fixing of Resin and Metal Components) The resin component 10 and the metal component 20 are fixed to each other at the direction change portion 23 of the metal component 20. Specifically, the insert-molded body 1 has a crimped portion 30 that fixes the resin component 10 and the metal component 20 at the direction change portion 23 of the metal component 20. FIG. 3 is a cross-sectional view taken along line B-B in FIG. 1 , showing how the resin component 10 and the metal component 20 are fixed to each other by the crimped portion 30. The metal component 20 has a hole at a position corresponding to the crimped portion 30. The crimped portion 30 is formed by extruding a resin material from a hole provided in the metal component 20 during compression molding. Therefore, the crimped portion 30 is made of the same resin material as the resin component 10.

[0053] Because the insert-molded body 1 is produced by heating during molding and then cooling to room temperature, each component constituting the insert-molded body 1 shrinks during cooling. In the case of an insert-molded body 1 having a resin part 10 and a metal part 20, the metal part 20 generally has a larger thermal expansion coefficient than the resin part 10, so the metal part 20 shrinks more than the resin part 10. In particular, in the direction-change portion 23 of the metal part 20 where the extension direction is changed, a contraction force with a different vector occurs during contraction. As a result, the direction-change portion 23 of the metal part 20 is particularly likely to lift off the resin part 10.

[0054] In the insert molded article 1 according to this embodiment, the resin part 10 and the metal part 20 are fixed to each other by the crimping part 30 at the turning part 23, which is prone to lifting up. This makes it possible to reduce the lifting up of the metal part 20.

[0055] (Reducing Lifting Due to Warpage of a Resin Component) When at least a portion of the metal component 20 is arranged along the thickness-varying portion 11 or the thin-walled portion 12, and the thickness-varying portions 11 and the thin-walled portions 12 alternate in a cross-sectional view perpendicular to the outer surface of the resin component 10, the relationship between the flatness Fa of the resin component 10 and the difference in thickness h between the thickness-varying portion 11 and the thin-walled portion 12 preferably satisfies 0 < Fa / h < 1.3. The flatness Fa is defined in the following steps 1 to 5. (Step 1) The resin component 10 is placed so that the surface of the outer surface of the thickness-varying portion 11 on which the metal component 20 is arranged (hereinafter simply referred to as the "arrangement surface") faces downward. (Step 2) The cross-section of the resin component 10 is observed in a cross-sectional view in which the thickness-varying portions 11 and the thin-walled portions 12 alternate. The observation area of ​​the resin component 10 is cut out so that the length Ly along the direction in which the thickness-varying portions 11 and the thin-walled portions 12 alternate is 40 cm. (Step 3) Focus on the placement surface of the uneven thickness portion 11 or the thin-walled portion 12 on which the metal component 20 is to be placed. (Step 4) Draw two parallel ideal lines with the minimum necessary vertical width so as to include the entire placement surface. (Step 5) Define the flatness Fa as the distance between the two ideal lines drawn in Step 4. Steps 1 to 5 are explained using Figures 9A and 9B. Note that Figures 9A, 9B, and 10 are drawn assuming that the metal component 20 is to be placed in the uneven thickness portion 11. Figure 9A shows the resin component 10 placed with the placement surface of the uneven thickness portion 11 facing downward. The uneven thickness portions 11 and the thin-walled portions 12 are alternately positioned along the Y-axis direction in Figure 9A. The Z-axis direction is the thickness direction of the resin component 10. Figure 9A shows a cross-section of the resin component 10 cut out from the observation area of ​​the resin component 10 so that the length Ly along the Y-axis direction is 40 cm, and observed along the Y-Z plane (Step 2). The arrangement surface of the uneven thickness portion 11 on which the metal component 20 is arranged is the area shown in 902 in Fig. 9B (Step 3). Two parallel ideal straight lines are exemplified by 901 in Fig. 9A. The two parallel ideal straight lines 901 are drawn so that the distance between them is minimized; in other words, the two parallel ideal straight lines 901 are drawn with the minimum necessary vertical width. Note that the method of turning the molded body in Fig. 9A upside down and observing and measuring with the surface of the thin-walled portion 12 in contact with the table top is not adopted in this disclosure.When the flatness Fa varies depending on the observation range, if there is even one portion that satisfies 0<Fa / h<1.3, it is considered that the surface on which the uneven thickness portion 11 is disposed satisfies 0<Fa / h<1.3.

[0056] The difference h in thickness between the uneven thickness portion 11 and the thin thickness portion 12 refers to the depth of the groove when observing a cross section in which the uneven thickness portions 11 and the thin thickness portions 12 are alternately located, as exemplified in Figure 10. When the height h of the resin part 10 varies depending on the measurement position, if h at at least one measurement position satisfies 0 < Fa / h < 1.3, it is considered that 0 < Fa / h < 1.3 is satisfied on the surface on which the uneven thickness portion 11 is located.

[0057] When Fa / h = 0, the surface of the thickness-uneven portion 11 on which the metal component 20 is disposed is a completely flat plane, i.e., an ideal plane. When the surface of the thickness-uneven portion 11 satisfies 0 < Fa / h, this means that the resin component 10 is warped so as to be convex toward the metal component 20. When Fa / h is 0 < Fa / h, the metal component 20 can be pulled toward the plane of the resin component 10 (the Y direction in FIG. 9A ), further reducing the lifting of the metal component 20 from the resin component 10. When Fa / h is < 1.3, the resin component 10 can be easily combined with other components, for example, facilitating the assembly of an automobile. More preferably, 0 < Fa / h ≦ 1.0, even more preferably, 0 < Fa / h ≦ 0.7, even more preferably, 0 < Fa / h ≦ 0.4, and most preferably, 0 < Fa / h ≦ 0.1. The preferred value of Fa is 0 mm or more and less than 30 mm, more preferably 0 mm or more and less than 20 mm, even more preferably 0 mm or more and less than 15 mm, still more preferably 0 mm or more and less than 10 mm, and most preferably 0 mm or more and less than 5 mm. The preferred value of h is 0 mm or more and less than 30 mm, more preferably 0 mm or more and less than 20 mm, even more preferably 0 mm or more and less than 15 mm, still more preferably 0 mm or more and less than 10 mm, and most preferably 0 mm or more and less than 5 mm.

[0058] Furthermore, in the insert molded body 1 according to this embodiment, the metal part 20 is arranged along the thickness deviation portion 11. An insert molded body 1 having such a configuration can be produced by placing the metal part 20 in a groove provided in the molding die 40 and molding it. Because the metal part 20 is placed in the groove of the molding die 40, the metal part 20 is easily positioned and molded. Note that it is not necessary for the entire metal part 20 to be arranged along the thickness deviation portion 11; positioning is easy as long as at least a portion of the metal part 20 is arranged along the thickness deviation portion 11.

[0059] Furthermore, in the insert-molded product 1 according to this embodiment, the first in-plane direction and the second in-plane direction in the metal part 20 are perpendicular to each other. When the first in-plane direction and the second in-plane direction in the metal part 20 are perpendicular to each other, the turning portion 23 connecting the first portion 21 and the second portion 22 is particularly likely to lift up. Therefore, by fixing the resin part 10 and the metal part 20 at the turning portion 23, it is possible to effectively reduce the lifting of the metal part 20. Furthermore, when it is desired to widely cover the outer surface of the resin part 10 with the metal part 20, the degree of freedom in arranging the metal part 20 can be increased by having the first in-plane direction and the second in-plane direction perpendicular to each other.

[0060] When the resin part 10 is formed of a fiber-reinforced composite material, it is preferable that the fiber volume fraction Vfa of the uneven thickness portion 11 is smaller than the fiber volume fraction Vfb of the thin-walled portion 12. In this case, a resin material with both flat main surfaces (a so-called plate-shaped resin material) can be used as the resin material placed in the molding die 40, allowing for a simple manufacturing method. A specific explanation is as follows. When the resin material placed in the molding die 40 is a resin material with both flat main surfaces (a so-called plate-shaped resin material), the thin-walled portion 12 is compressed by the molding die 40 during molding. At this time, the resin components in the thin-walled portion 12 flow toward the uneven thickness portion 11, while the fibers contained in the resin material remain in the thin-walled portion 12. As a result, the fiber volume fraction Vfa of the uneven thickness portion 11 is smaller than the fiber volume fraction Vfb of the thin-walled portion 12.

[0061] The fiber volume fraction Vfa of the uneven thickness portion 11 is, for example, 25 to 45%, and preferably 30 to 40%. The fiber volume fraction Vfb of the thin thickness portion 12 is, for example, 30 to 50%, and preferably 35 to 45%. The difference (Vfb - Vfa) between the fiber volume fraction Vfa of the uneven thickness portion 11 and the fiber volume fraction Vfb of the thin thickness portion 12 is, for example, 1 to 15%, and preferably 3 to 12%.

[0062] When the resin part 10 is made of a fiber-reinforced composite material, the resin part 10 preferably includes a first resin layer 13 and a second resin layer 14 that is disposed closer to the metal part 20 than the first resin layer 13, and the fiber volume fraction Vf1 of the first resin layer 13 is preferably greater than the fiber volume fraction Vf2 of the second resin layer 14. Having the first resin layer 13 and the second resin layer 14 that satisfy the above-described relationship in fiber volume fractions makes it possible to suppress warping of the resin part 10. The reason for this is explained below.

[0063] FIG. 4 is an enlarged cross-sectional view of a portion of a resin part 110 that does not include resin layers with different fiber volume fractions (i.e., resin layers corresponding to the first resin layer 13 and the second resin layer 14). The resin part 110 is a part formed by compressing a plate-shaped resin material in a molding die to provide a thickness-uneven portion 111 and a thin-walled portion 112. As shown in FIG. 4 , the resin part 110 has regions 110A (region A), 110B (region B), and 110C (region C), each with a different fiber orientation and fiber volume fraction. Region A is located above the thickness-uneven portion 111 and protrudes upward in a cross-sectional view. Region B is located below the thickness-uneven portion 111 and is a region located below Region A. The differences in fiber orientation and fiber volume fraction in each region arise because the uneven shape of the resin part 110 causes fibers to flow differently in each region during compression molding. The multiple dashed lines F in Figure 4 are lines that schematically show the fiber orientation and density in each region. Note that the dashed lines F are added for convenience of explanation and do not represent the exact position, orientation, density, etc. of the fibers contained in the resin part 110. As shown in Figure 4, region A has a relatively strong fiber orientation along the thickness direction, so region A hardly shrinks when cooled. Region B has a high fiber volume fraction and a small linear expansion coefficient, so it shrinks little when cooled. Region C has a low fiber volume fraction and a large linear expansion coefficient, so it shrinks most easily when cooled. Because of this difference in shrinkage rate during cooling between regions A, B, and C, an insert-molded body 1 that does not have resin layers with different fiber volume fractions and has an uneven shape such as the uneven-walled portion 11 and the thin-walled portion 12 is prone to warping during cooling during the molding process.

[0064] FIG. 5 is a cross-sectional view illustrating the first resin layer 13 and the second resin layer 14. When the insert-molded body 1 has resin layers with different fiber volume fractions, warping occurs during cooling due to the difference in shrinkage rate of each resin layer. When the first resin layer 13 and the second resin layer 14 are laminated as shown in FIG. 5 and the fiber volume fraction Vf1 of the first resin layer 13 is greater than the fiber volume fraction Vf2 of the second resin layer 14, the warping caused by the different fiber orientations in regions A to C in FIG. 4 and the warping caused by the difference in shrinkage rate of the resin layers can be offset. This reduces warping overall.

[0065] The fiber volume fraction Vf1 of the first resin layer 13 is, for example, 25 to 45%, and preferably 30 to 40%. The fiber volume fraction Vf2 of the second resin layer 14 is, for example, 15 to 35%, and preferably 20 to 30%. The difference (Vf1 - Vf2) between the fiber volume fraction Vf1 of the first resin layer 13 and the fiber volume fraction Vf2 of the second resin layer 14 is, for example, 3 to 20%, and preferably 5 to 15%.

[0066] The fiber volume fraction of the resin part 10 can be determined, for example, by the following method. A 100 mm x 100 mm sample is cut from the resin part 10, and (i) the weight of the resin part is measured. (ii) The sample is heated to 550°C in a nitrogen atmosphere in an electric furnace (FP410 manufactured by Yamato Scientific Co., Ltd.) for 4 hours to burn off organic matter such as the matrix resin, and the weight is measured. The weights of (i) and (ii) are weighed to calculate the weight of the resin and reinforcing fibers. Next, the volume fraction of the reinforcing fibers is calculated using the specific gravity of each component according to the following formula (1): Fiber volume fraction = 100 x reinforcing fiber volume / (reinforcing fiber volume + resin volume) (1)

[0067] When the resin part 10 is formed from a fiber-reinforced composite material, the weight-average fiber length of the reinforcing fibers contained in the resin part 10 is preferably 100 mm or less. A weight-average fiber length of 100 mm or less can reduce warpage of the insert-molded body 1 having the uneven-walled portion 11 and the thin-walled portion 12. The weight-average fiber length of the reinforcing fibers contained in the resin part 10 is preferably 50 mm or less, more preferably 30 mm or less, and even more preferably 20 mm or less. There is no particular lower limit for the weight-average fiber length, but it is, for example, 1 mm or more.

[0068] The weight-average fiber length of the reinforcing fibers contained in the resin part 10 can be determined, for example, by the following method: The fiber lengths of 100 fibers randomly extracted from the resin part 10 are measured to the nearest 1 mm using a vernier caliper or the like. If the fiber length of each reinforcing fiber is Li and the number of fibers measured is j, the weight-average fiber length (Lw) can be determined by the following formula (a):

[0069]

[0070] In the insert-molded product 1 according to the present disclosure, when the direction perpendicular to the outer surface of the resin part 10 is defined as the thickness direction, the difference in thickness between the uneven thickness portion 11 and the thin-walled portion 12 is preferably equal to or greater than the thickness of the metal part 20. If the difference in thickness between the uneven thickness portion 11 and the thin-walled portion 12 is equal to or greater than the thickness of the metal part 20, the depth of the groove provided in the molding die 40 to form the uneven thickness portion 11 will be at least twice the thickness of the metal part 20, making it easy to position and mold the metal part 20. When the metal parts 20 are stacked or integrated, the above-mentioned effect can be obtained if the difference in thickness between the uneven thickness portion 11 and the thin-walled portion 12 is equal to or greater than the thickness of each metal part 20, but more preferably, it is equal to or greater than the total thickness of the stacked or integrated metal parts 20.

[0071] In the insert molded body 1 according to the present disclosure, the thickness deviation portions 11 and the thin-walled portions 12 are preferably alternately positioned in a cross section perpendicular to the outer surface of the resin part 10. In the insert molded body 1 according to the present embodiment, as shown in FIG. 2 , the thickness deviation portions 11 and the thin-walled portions 12 are alternately positioned in a cross section perpendicular to the outer surface of the resin part 10. Because the metal part 20 is arranged along the thickness deviation portions 11 or the thin-walled portions 12, this configuration allows the metal part 20 to be positioned evenly on the resin part 10. Note that a "cross section perpendicular to the outer surface of the resin part 10" is not uniquely defined, but when the thickness deviation portions 11 and the thin-walled portions 12 are alternately positioned in any cross section perpendicular to the outer surface of the resin part 10, this is considered to be "when the thickness deviation portions 11 and the thin-walled portions 12 are alternately positioned in a cross section perpendicular to the outer surface of the resin part 10." It is more preferable that the thickness deviation portions 11 and the thin-walled portions 12 are alternately positioned in all cross sections perpendicular to the outer surface passing through the center of gravity of the resin part 10.

[0072] Furthermore, in the insert molded article of the present disclosure, the metal component may be disposed along the thin-walled portion rather than the uneven thickness portion; for such a configuration, see the embodiment shown in Figure 12, which will be described later. An insert molded article having such a configuration can be produced, for example, by arranging the metal material in the convex portion rather than the concave portion in the molding die 40 shown in Figure 6. Note that the entire metal component does not need to be disposed along the thin-walled portion; as long as at least a portion of the metal component is disposed along the thin-walled portion, the position of the metal component in the molded article is less likely to shift.

[0073] (Impact Detection Sensor) A battery tray or a battery tray protective cover according to the present disclosure includes the insert molding according to the present disclosure. In a battery tray or a battery tray protective cover including the insert molding according to the present disclosure, the metal part is, for example, an electrical circuit for impact detection. Fig. 11 shows an example of a battery tray protective cover 1102 mounted on a vehicle 1101. The battery tray protective cover 1102 includes an electrical circuit 1103 for impact detection.

[0074] Batteries installed in electric vehicles are heavy and are placed under the vehicle floor, protected by the vehicle structure, to achieve a low center of gravity. During high-speed driving, flying stones and other objects can damage the batteries installed in the vehicle, and at low speeds, they can also be damaged by contact with the ground during parking. Therefore, electric vehicles often have sturdy battery trays or have battery tray protective covers attached to the bottom of the battery tray to protect the battery box from underneath. In such cases, in the past, the driver was responsible for determining whether the vehicle needed to be inspected at a repair shop after an impact. However, because visibility underneath the vehicle is poor, an expert's eye is required to accurately assess the damage, making it difficult to accurately estimate the extent of the impact. Therefore, by using the metal parts disclosed herein as an impact detection electrical circuit, it is possible to detect and classify the impact severity, and to alert the driver if the battery is completely destroyed. This can prevent holes from being created in the battery tray or its protective cover, which could lead to a battery fire. Furthermore, the electrical circuitry allows for more specific identification of damaged areas, allowing battery management to evacuate cells in the damaged areas to prevent fire risks.

[0075] (Inverter Box) The inverter box of the present disclosure includes the insert molded article of the present disclosure. In an inverter box including the insert molded article of the present disclosure, the metal part is, for example, an electrical circuit. An inverter is a device that converts direct current (DC) supplied from a battery into alternating current (AC), and an inverter box is a box for storing the inverter. In the inverter box of the present disclosure, the current circuit is insert-molded into a thin-walled portion (recess), and it is preferable that a metal part is placed there and fixed to a resin part. FIG. 12 shows a cross-sectional view of an insert molded article 1201 used in the inverter box. The insert molded article 1201 has a thickness-uneven portion 1203 and a thin-walled portion 1204 made of resin, and an electrical circuit 1202 is embedded in the thin-walled portion 1204 (recess).

[0076] [Method for manufacturing insert molded body] Next, a method for manufacturing the insert molded body 1 according to one embodiment of the present disclosure will be described. Fig. 6 is a diagram showing a molding die 40 for producing the insert molded body 1. The molding die 40 is composed of an upper die 41 and a lower die 42.

[0077] FIG. 6 illustrates an example of a molding die used to produce an insert-molded product 1 in which at least a portion of a metal part is disposed along the thickness deviation portion. As shown in FIG. 6 , a groove is formed in the lower die 42, and a metal material 50 is placed in the groove of the lower die 42 to fit into the groove. The metal material 50 typically has the same shape as the molded metal part 20. That is, the metal material 50 has a turning portion 23, and the turning portion 23 has a hole for forming the crimped portion 30. Next, a flat thermoplastic resin material (not shown) is placed between the upper die 41 and the lower die 42, and the molding die 40 is heated to 150°C and closed to perform compression molding. During this compression molding process, the resin material flows into the groove of the lower die 42 to form the thickness deviation portion 11. Furthermore, the resin material is extruded through the hole in the turning portion 23 of the metal material 50 to form the crimped portion 30. Thereafter, the molding die 40 is cooled to room temperature to obtain the insert-molded body 1 in which the metal part 20 and the resin part 10 are integrated. At this time, the metal part 20 and the resin part 10 are fixed to each other by the formed crimped portion 30.

[0078] The insert molded body 1 molded in this manner has a resin part 10 and a metal part 20. The resin part 10 has a thickness deviation portion 11 and a thin-walled portion 12 that is thinner than the thickness deviation portion 11. At least a portion of the metal part 20 is disposed on the outer surface of the resin part 10 along the thickness deviation portion 11 or the thin-walled portion 12. The metal part 20 has a deflection portion 23 in which the direction of extension on the outer surface is changed. Note that although the resin part 10 is located above the metal part 20, if the resulting molded body is turned upside down, it will match the configuration of the insert molded body 1 shown in Figure 2. The detailed configuration of the insert molded body 1 will be described above, and duplicate content will be omitted.

[0079] The manufacturing method of the insert molded body 1 of the present disclosure includes a step of fixing the resin part 10 and the metal part 20 to each other at the direction change portion 23. The specific aspect of the fixing step is not particularly limited as long as it can reduce lifting of the metal part 20 from the resin part 10 at the direction change portion 23. As in the above-described embodiment, it is preferable to fix the resin part 10 and the metal part 20 to each other at the direction change portion 23 simultaneously with molding of the insert molded body 1.

[0080] In the manufacturing method of the insert molded body 1, the insert molded body 1 preferably further includes a sealing layer that seals the metal component 20, and the manufacturing method preferably includes a step of molding the sealing layer together with the resin component 10 and the metal component 20. For example, as shown in FIG. 6 , a sealing material 60, which is the material for the sealing layer, is placed together with the metal material 50 and then molded, thereby molding the sealing layer together with the resin component 10 and the metal component 20. This allows the sealing layer to protect the insert molded body 1 and provide insulation without a separate process. The sealing layer may also serve as a sealant for the metal material, and may be a layer intended for purposes such as electrical insulation, prevention of corrosion due to contact with water or gas, and prevention of damage due to vibration. The material of the sealing layer is not particularly limited, and various materials can be used depending on the purpose, including metals such as iron, metal oxides, inorganic materials such as silica, inorganic mineral particles, and resin compositions. Furthermore, epoxy resin, silicone resin, or thermoplastic resin may be used as a matrix resin, optionally containing organic substances that serve as various stabilizers and absorbents, or non-conductive metals such as iron oxide. While Figure 6 shows an embodiment in which the sealing material 60 is placed on the lower mold 42 together with the metal material 50, the manufacturing method of the insert molded body 1 having a sealing layer is not limited to this embodiment. The method for molding the sealing layer may be injection molding or compression molding, and can be selected appropriately depending on the manufacturing equipment, the shape and material of the sealing layer, etc. Furthermore, although Figure 6 shows an example of a method for manufacturing an insert molded body having a sealing layer, the manufacturing method of the insert molded body of the present disclosure can also be applied to an insert molded body without a sealing layer. In other words, the sealing material 60 is not required.

[0081] When the sealing layer is formed by injection molding, for example, a supply path for supplying the injection material is provided in the lower mold 42. By injecting the injection material into the mold during insert molding, the insert-molded article 1 having the sealing layer can be obtained.

[0082] When molding the insert-molded body 1 by compression molding, the charge rate of the resin material is preferably 90% or higher, more preferably 95% or higher, and even more preferably 99% or higher. The upper limit of the charge rate is not particularly limited, and it may exceed 100%, but to reduce material waste, it is preferably 100% or lower. The charge rate of the resin material during compression molding is the ratio (A2 / A1) of the area A2 of the resin material placed in the mold 40 before molding to the area A1 of the insert-molded body 1 in a plan view. A high charge rate suppresses the in-plane flow of the matrix resin, thereby reducing unevenness in the fiber content of the molded resin part 10. This improves the processability of the insert-molded body 1.

[0083] Although the present disclosure has been described above in accordance with specific embodiments, the present disclosure is not limited to these embodiments.

[0084] Another aspect of the turning portion 23 of the metal part 20 will be described with reference to the drawings. FIG. 7 is a diagram showing an insert-molded body 1 according to a second embodiment of the present disclosure. In the insert-molded body 1 shown in FIG. 7 , the metal part 20 has a first portion 21 extending in the vertical direction of the page and a second portion 22 extending in the horizontal direction of the page, and is connected to both the first portion 21 and the second portion 22 by a turning portion 23 extending in a direction that differs by 45 degrees. In the first embodiment, the first portion 21 and the second portion 22 are directly connected to each other perpendicularly. However, in the second embodiment, the first portion 21 and the second portion 22 do not directly intersect but are indirectly connected via the turning portion 23. In this embodiment, the entire portion extending in a direction that differs by 45 degrees from both the first portion 21 and the second portion 22 can be considered to be the turning portion 23.

[0085] FIG. 8 is a diagram illustrating an insert-molded body 1 according to a third embodiment of the present disclosure. In the insert-molded body 1 illustrated in FIG. 8 , the metal part 20 has a first portion 21 extending vertically in the plane of the drawing and a second portion 22 extending horizontally in the plane of the drawing. The first portion 21 and the second portion 22 are connected by a quadrant-arc portion 231. In this case, the entire quadrant-arc portion 231 can be considered a turning portion. That is, not only the turning portion having a linear shape like the first and second embodiments, but also the turning portion having a shape that continuously changes direction like this embodiment can be considered as a turning portion 23. In this embodiment, a semicircular portion 232 connects a first portion 21 to another first portion 21 extending parallel to the first portion 21. In this case, the entire semicircular portion 232 can also be considered as a turning portion 23.

[0086] Furthermore, in the insert-molded body 1 according to the above embodiment, the resin part 10 and the metal part 20 are fixed to each other by the crimping portion 30 formed from a resin material, but this is not limiting. For example, the resin part 10 and the metal part 20 may be fixed to each other at the direction change portion 23 after the insert-molded body 1 is removed from the molding die 40. The fixing method may be mechanical fixing using bolts, rivets, or the like, or may use an adhesive or the like. However, from the viewpoint of manufacturing efficiency, it is preferable to fix the parts to each other during the molding process.

[0087] Furthermore, in the insert-molded body 1 according to the above embodiment, the first in-plane direction and the second in-plane direction are perpendicular to each other. However, the first in-plane direction and the second in-plane direction do not have to be perpendicular as long as they extend in different directions. The angle between the first in-plane direction and the second in-plane direction is preferably 10 degrees or greater and 170 degrees or less, more preferably 20 degrees or greater and 160 degrees or less, and even more preferably 45 degrees or greater and 135 degrees or less. Here, the angle between the first in-plane direction and the second in-plane direction refers to the angle between a vector originating from the turning portion 23 and heading toward the first portion 21 and a vector originating from the turning portion 23 and heading toward the second portion 22 in the first portion 21 and the second portion 22 connected to each other by the turning portion 23. The angle between the first in-plane direction and the second in-plane direction is defined to be in the range of 0 degrees or greater and 180 degrees or less.

[0088] Furthermore, in the description of the insert-molded body 1 according to the above embodiment, the positions of the first portion 21 and the second portion 22 were specified with reference to the drawings, but the first portion 21 and the second portion 22 can be set to any portion in which the metal part 20 extends. In other words, the first portion 21 and the second portion 22 shown in the drawings are merely examples, and other portions can be set as the first portion 21 or the second portion 22. Accordingly, the first in-plane direction and the second in-plane direction can also be set to any direction in which the metal part 20 extends. If the angle formed by at least one of the combinations of the first in-plane direction and the second in-plane direction that can be set is within the above range, it can be said that "the angle formed by the first in-plane direction and the second in-plane direction is within the range."

[0089] Furthermore, in the manufacturing method of the insert-molded article 1 according to the above embodiment, a mode in which a resin material is compression-molded has been described, but it may be formed by other molding methods such as injection molding. The effects of the present disclosure can be obtained by any molding method in which heating is performed at a temperature higher than room temperature during molding.

[0090] The insert molded article and method for manufacturing an insert molded article according to the present disclosure are applicable to parts for various moving objects, industrial machines, etc., such as vehicle impact detection sensors, coils, and planar heating elements.

[0091] DESCRIPTION OF SYMBOLS 1, 1201: Insert molded body 10: Resin part 11, 1203: Uneven thickness portion 12, 1204: Thin-walled portion 13: First resin layer 14: Second resin layer 20, 1202: Metal part 21: First part 22: Second part 23: Turning part 30: Crimping part 40: Mold 41: Upper mold 42: Lower mold 50: Metal material 60: Sealing material 110: Resin part 110A: Region A 110B: Region B 110C: Region C 111: Uneven thickness portion 112: Thin-walled portion 901: Two parallel ideal straight lines 902: Arrangement surface of uneven thickness portion 11 on which metal part 20 is arranged 1101: Vehicle 1102: Protective cover for battery tray 1103: Electrical circuit for impact detection

Claims

1. An insert molded body having a resin part and a metal part, wherein the resin part has a thickness deviation portion and a thin-walled portion that is thinner than the thickness deviation portion, at least a portion of the metal part is disposed on an outer surface of the resin part along the thickness deviation portion or the thin-walled portion, the metal part has a change-in part in which the direction of extension on the outer surface is changed, and the resin part and the metal part are fixed to each other at the change-in part.

2. The insert molding according to claim 1, wherein at least a portion of the metal part is disposed along the thin-walled portion.

3. The insert molding according to claim 1, wherein at least a portion of the metal part is disposed along the uneven thickness portion.

4. The insert molding according to any one of claims 1 to 3, wherein the metal part has a first portion extending in a first in-plane direction and a second portion extending in a second in-plane direction different from the first in-plane direction, and the redirecting portion connects the first portion and the second portion.

5. The insert molded article according to claim 4, wherein the first in-plane direction and the second in-plane direction are perpendicular to each other.

6. The insert molding according to any one of claims 1 to 5, wherein the resin part is formed from a fiber-reinforced composite material, and a fiber volume fraction Vfa of the uneven wall portion is smaller than a fiber volume fraction Vfb of the thin wall portion.

7. The insert molding according to any one of claims 1 to 6, wherein the resin part is formed from a fiber-reinforced composite material, the resin part has a first resin layer and a second resin layer arranged on the metal part side of the first resin layer, and a fiber volume fraction Vf1 of the first resin layer is greater than a fiber volume fraction Vf2 of the second resin layer.

8. The insert molding according to any one of claims 1 to 7, wherein the resin part is formed from a fiber-reinforced composite material, and the weight-average fiber length of the reinforcing fibers contained in the resin part is 100 mm or less.

9. The insert molded body according to claim 2 or 3, wherein, when the direction perpendicular to the outer surface of the resin part is the thickness direction, the difference in thickness between the uneven thickness portion and the thin-walled portion is equal to or greater than the thickness of the metal part.

10. The insert molded body according to any one of claims 1 to 9, wherein, in a cross-sectional view perpendicular to the outer surface of the resin part, the uneven thickness portions and the thin-walled portions are positioned alternately.

11. The insert molded product according to claim 10, wherein at least a portion of the metal part is disposed along the uneven thickness portion or the thin-walled portion, and the relationship between the flatness Fa of the resin part and the difference in thickness h between the uneven thickness portion and the thin-walled portion satisfies 0<Fa / h<1.

3.

12. A battery tray or a protective cover for a battery tray, comprising the insert molding according to any one of claims 1 to 11, wherein the metal part is an electric circuit for impact detection.

13. An inverter box comprising the insert molding according to any one of claims 1 to 11, wherein the metal part is an electric circuit.

14. A manufacturing method for an insert molded body having a resin part and a metal part, wherein the resin part has a thickness deviation portion and a thin-walled portion thinner than the thickness deviation portion, at least a portion of the metal part is disposed on an outer surface of the resin part along the thickness deviation portion or the thin-walled portion, and the metal part has a turning portion whose extending direction on the outer surface is changed, the method including a step of fixing the resin part and the metal part to each other at the turning portion.

15. The method for producing an insert molded body according to claim 14, wherein the insert molded body further has a sealing layer that seals the metal part, and the method includes a step of molding the sealing layer together with the resin part and the metal part.

Images