Resin mold structure, insert molded component, and insert member for insert molded component

Abstract

The present invention enhances bonding strength between an insert member and a resin constituting an insert molded component.　This resin mold structure is a structure formed by insert molding an insert member 100 with a resin 200. A first recess 110 and a second recess 120 are provided in a predetermined face of the insert member 100. The first recess 110 and the second recess 120 communicate with each other. The resin 200 is present in the first recess 110 and the second recess 120.

Description

Resin mold structure, insert molded part, and insert member for insert molded part

[0001] The present disclosure relates to a resin molded structure, an insert molded part, and an insert member for an insert molded part.

[0002] BACKGROUND ART In electronic products and the like, a structure is used in which a recess is formed in part of an insert member made of metal, ceramic, or the like by laser processing or the like, and then insert molding is performed to improve the bonding strength with the mold resin.

[0003] Patent Document 1 discloses a metal-resin composite molding in which a surface of an insert metal member is irradiated with laser light having a predetermined spot diameter to form multiple recesses on the surface, forming a roughened area with multiple wave-shaped extensions, and a resin member is molded into the roughened area.

[0004] JP 2017-56736 A

[0005] In conventional insert members used in insert molded parts, the recesses are formed by unidirectional laser irradiation, resulting in a dead-end shape. This means that the air in the recesses cannot be fully evacuated during molding. This makes it difficult to fully fill the recesses with resin. As a result, the undercut function of the recesses is not fully realized, and the resin that has entered the recesses may not fully contribute to improving the joining strength.

[0006] The metal-resin composite molded body described in Patent Document 1 does not solve the problem of the dead end of the recess, and there is thought to be room for improvement.

[0007] An object of the present disclosure is to increase the bonding strength between an insert member and a resin that constitutes an insert molded part.

[0008] The resin molded structure of the present disclosure is a structure formed by insert molding an insert member with resin, and a first recess and a second recess are provided on a predetermined surface of the insert member, the first recess and the second recess are connected, and resin has entered the first recess and the second recess.

[0009] According to the present disclosure, it is possible to increase the bonding strength between the insert member and the resin that constitutes the insert molded part.

[0010] Fig. 2 is a perspective view showing an insert molded part of Example 1. Fig. 3 is an enlarged schematic cross-sectional view showing a resin molded structure of the insert molded part of Fig. 1. Fig. 4 is an enlarged schematic cross-sectional view showing a resin molded structure of a conventional insert molded part. Fig. 5 is an enlarged schematic cross-sectional view showing a desirable resin molded structure of Example 1. Fig. 6 is an enlarged schematic cross-sectional view showing a resin molded structure of the insert molded part of Example 2. Fig. 7 is an enlarged schematic cross-sectional view showing a desirable resin molded structure of Example 2.

[0011] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. The embodiments are examples for explaining the contents of the present disclosure, and some omissions and simplifications have been made as appropriate for clarity of explanation. The present disclosure can be implemented in various other forms. Unless otherwise specified, each component may be singular or plural.

[0012] To facilitate understanding of the invention, the position, size, shape, range, etc. of each component shown in the drawings may not represent the actual position, size, shape, range, etc. Therefore, the present disclosure is not necessarily limited to the position, size, shape, range, etc. disclosed in the drawings.

[0013] FIG. 1 is a perspective view showing an insert molded part according to a first embodiment.

[0014] The insert molded part shown in this figure has a configuration in which an insert member 100 is insert-molded into resin 200. In the figure, the right side and bottom surface of the insert member 100 are exposed to the outside. In this figure, the insert member 100 is rectangular prism-shaped, and the overall shape of the insert molded part is also rectangular prism-shaped. However, the overall shape of the insert member 100 and the insert molded part is not limited to a rectangular prism, and may be a polygonal column, a cylindrical column, an elliptical column, or the like other than a rectangular prism. Furthermore, burrs, sagging, etc. formed during cutting, punching, etc. may remain on the insert member 100.

[0015] It should be noted that the insert member 100 does not need to have an exposed surface as shown in this figure, and the effect of the insert molded part of the present disclosure can be obtained regardless of the configuration of the insert molded part.

[0016] The insert member 100 is made of metal, ceramic, or the like. As the metal, an alloy containing copper, nickel, iron, platinum, or the like as a main component is used. However, the type of alloy is not limited to these examples. As the ceramic, silica, alumina, or the like is used. However, the type of ceramic is not limited to these examples. Furthermore, as the resin, polyethylene, polypropylene, polyacrylonitrile, polycarbonate, polyamide, polyimide, polyacetal, or the like is used. However, the type of resin is not limited to these examples.

[0017] FIG. 2 is an enlarged schematic cross-sectional view showing the resin mold structure of the insert molded part of FIG.

[0018] FIG. 2 shows the joint (boundary) between the insert member 100 and the resin 200 .

[0019] A first recess 110 and a second recess 120 are formed on the flat surface (one flat face) of the insert member 100 that constitutes the joint. The first recess 110 and the second recess 120 are formed by laser irradiation from different directions. The first recess 110 and the second recess 120 intersect spatially and partially share a space. This space is covered by a bridge 130. In other words, the first recess 110 and the second recess 120 are in communication with each other.

[0020] Here, the flat surface refers to, for example, one of the planes constituting the quadrangular prism in the case of the insert member 100 in the shape of a quadrangular prism shown in Figure 1. Such a plane is surrounded by several ridges (four ridges in the case of a quadrangular prism). Furthermore, if the insert member 100 is cylindrical, the circular bottom surface is of course a flat surface. The side surface of a cylinder is also a convex surface with no ridges, and when viewed partially, the side surface can be said to be a nearly flat surface.

[0021] In summary, in this specification, the term "flat surface" refers to a surface that does not include ridges or vertices macroscopically, and includes both convex and concave surfaces.

[0022] In addition, since the insert member 100 may have burrs, sagging, etc. formed during cutting, punching, etc., burrs, sagging, etc. may be present on the actual flat surface, or on either the ridge line or the vertex.

[0023] The first recess 110 and the second recess 120 are filled with a resin 200 .

[0024] A first burr 111 is formed on the periphery of the first opening, which is the entrance of the first recess 110. Meanwhile, a second burr 121 is formed on the periphery of the second opening, which is the entrance of the second recess 120. Furthermore, a third burr 122 is formed on the inner wall of the first recess 110. Note that a "burr" is also called a "protrusion."

[0025] The laser is first irradiated from the direction in which the first recess 110 is formed. At this time, a first burr 111 is formed. Next, the laser is irradiated from the direction in which the second recess 120 is formed. At this time, a second burr 121 is formed. The laser that forms the second recess 120 also hits the inner wall surface of the existing first recess 110. As a result, a third burr 122 is formed. In summary, the third burr 122 is formed by forming the second recess 120 after forming the first recess 110.

[0026] When a laser is irradiated onto the insert member 100, the temperature of the irradiated portion rises instantaneously, causing part of the insert member 100 to melt and evaporate, forming a recess. At the same time, the melted and evaporated insert member 100 is instantaneously cooled by the air or nearby insert members 100, and adheres to the insert member 100, forming a burr.

[0027] Because the first recess 110 and the second recess 120 are connected, when the resin is filled, the resin can easily enter and the air in the recess can easily be discharged. In other words, the volume of the dead end of the recess is small, and most of the air in the recess can easily be pushed out by the resin. This promotes filling with the resin.

[0028] The bonding strength between the insert member 100 and the resin 200 can be improved because the first recess 110 and the second recess 120 are easily filled with resin, the resin bonds where the first recess 110 and the second recess 120 communicate with each other (in other words, the bridge 130 becomes an undercut), and the first burr 111, the second burr 121, and the third burr 122 increase the contact area with the resin 200. Note that the bridge 130 has a larger volume as an undercut than the burr, and therefore contributes greatly to improving the bonding strength.

[0029] Although only one set of the first recess 110 and the second recess 120 is shown in this figure, in reality, these sets are arranged vertically and horizontally. These sets may be arranged regularly or irregularly. The spacing between these sets is not particularly limited, and if necessary, they may be arranged so closely that the openings of adjacent sets overlap.

[0030] Furthermore, although this embodiment shows a case where there are two recesses in one set, the resin mold structure of the present disclosure is not limited to this, and the number of recesses in one set may be three or more. In other words, a configuration may be provided in which one or more other recesses are provided that communicate with at least one of the first recess 110 and the second recess 120. If there are a large number of communicating recesses, the shape of the resin inside the recess becomes complex, the number of burrs increases, and the orientation of the burrs becomes diverse, making it easier for the resin to fill and further improving the bonding strength.

[0031] The laser spot diameter is preferably about 10 μm to 100 μm, and the laser is preferably irradiated in pulses.

[0032] When the above-described sets of recesses are arranged regularly, for example, first, a pulsed laser beam is irradiated at the same angle relative to the surface while moving the laser device, thereby forming a plurality of first recesses 110. Next, the angle is changed, and a pulsed laser beam is irradiated at the changed angle while moving the laser device, thereby forming a plurality of second recesses 120.

[0033] In this embodiment, the recesses are formed using a laser, but the resin mold structure of the present disclosure is not limited to this, and the recesses may be formed using drilling or punching.

[0034] Comparative Example FIG. 3 is an enlarged schematic cross-sectional view showing a resin mold structure of a conventional insert molded part as a comparative example.

[0035] As shown in this figure, in the resin mold structure of a conventional insert molded part, one recess 310 is formed at one location on the surface of the insert member 100. In this case, one recess 310 is formed by irradiating the surface with a laser beam once from a direction perpendicular to the surface. As a result, a burr 311 is formed at the opening, which is the entrance to the recess 310.

[0036] In the resin mold structure of this comparative example, when the resin 200 is filled, air tends to remain in the recess 310, making it difficult for the resin 200 to enter. As a result, the bonding strength between the insert member 100 and the resin 200 may not be sufficiently high.

[0037] Next, a desirable configuration of the first embodiment will be described.

[0038] FIG. 4 is an enlarged schematic cross-sectional view showing a desirable resin mold structure of Example 1.

[0039] In this figure, hatching is applied to the portions corresponding to the tip of the second recess 120 and the third burr 122 in Figure 2. The boundary indicated by the dotted line corresponds to the inner wall surface of the first recess 110 in a state where the tip of the second recess 120 and the third burr 122 are not formed in the first recess 110. In other words, the tip of the second recess 120 is a portion of the second recess 120 that is deeper than the inner wall surface of the first recess 110.

[0040] As mentioned above, in laser processing, the insert material that was present in the recess before the recess was formed melts, evaporates, and moves, forming a burr, due to the laser irradiation. Therefore, there is a correlation between the volume of the recess and the volume of the burr.

[0041] It is desirable to adjust the conditions of the laser processing so that the volume of the third burr 122 is 50% or more of the volume of the tip of the second recess 120. In this case, even if the volume of the third burr 122 becomes 100% of the volume of the tip of the second recess 120, the third burr 122 is dispersed and therefore is not likely to block the first recess 110. This allows the resin 200 to enter the space in the three-dimensional structure formed by the tip of the second recess 120 and the third burr 122, further increasing the bonding strength.

[0042] FIG. 5 is an enlarged schematic cross-sectional view showing the resin mold structure of the insert molded part of Example 2.

[0043] This figure shows the joint (boundary) between the ridge or apex of the insert member 100 and the resin 200. In the following description, the same configuration as in FIG. 2 will not be described.

[0044] Two flat surfaces intersect at the ridge of the insert member 100 that constitutes the joint, and three flat surfaces intersect at the apex. As shown in FIG. 5 , a first recess 110 is formed on one surface, and a second recess 120 is formed on the other surface. The first recess 110 and the second recess 120 are formed by laser irradiation from different directions. The first recess 110 and the second recess 120 are connected to each other. The bridge 130 includes the ridge or apex of the insert member 100.

[0045] The vertex is configured such that the two flat surfaces shown in the figure intersect with another flat surface (not shown). In this case, another recess is provided on the other flat surface. The other recess communicates with at least one of the first recess 110 and the second recess 120.

[0046] In this specification, "two intersecting flat surfaces" refers to a state in which two surfaces that do not include a ridgeline or a vertex intersect to form a ridgeline from a macroscopic perspective, and "three intersecting flat surfaces" refers to a state in which three surfaces that do not include a ridgeline or a vertex intersect to form a ridgeline and a vertex from a macroscopic perspective.

[0047] In this embodiment, as in the first embodiment, the bonding strength between the insert member 100 and the resin 200 can be improved.

[0048] FIG. 6 is an enlarged schematic cross-sectional view showing a desirable resin mold structure of Example 2.

[0049] In this drawing, hatching is applied to the portions corresponding to the tip end of the second recess 120 and the third burr 122 in FIG.

[0050] FIG. 6 also shows that there is a correlation between the volume of the recessed portion and the volume of the burr, similar to FIG. 4 of Example 1.

[0051] In this embodiment as well, it is desirable to adjust the conditions of the laser processing so that the volume of the third burr 122 is 50% or more of the volume of the tip of the second recess 120 .

[0052] 100: insert member, 110: first recess, 111: first burr, 120: second recess, 121: second burr, 122: third burr, 130: bridge, 200: resin.

Claims

1. A resin molded structure formed by insert molding an insert member with resin, wherein a first recess and a second recess are provided on a specific surface of the insert member, the first recess and the second recess are connected, and the resin has penetrated into the first recess and the second recess.

2. The resin mold structure according to claim 1, wherein a protrusion is formed on the inner wall of said first recess.

3. The resin mold structure according to claim 1, wherein a protrusion is formed on the periphery of the opening of said first recess and said second recess.

4. The resin mold structure according to claim 2, wherein the volume of the protrusion formed on the inner wall of the first recess is 50% or more of the volume of the tip of the second recess.

5. A resin molded structure as described in claim 1, wherein the predetermined surface of the insert member is provided with one or more other recesses communicating with at least one of the first recess and the second recess.

6. The resin mold structure according to claim 1, wherein the predetermined surface of the insert member is constituted by a single flat surface, and the first recess and the second recess are provided in the single flat surface.

7. The resin molded structure as described in claim 1, wherein the predetermined surface of the insert member includes two flat surfaces, the first recess is provided in one of the two flat surfaces, and the second recess is provided in the other of the two flat surfaces.

8. A resin molded structure as described in claim 7, wherein the predetermined surface of the insert member further includes another flat surface, and another recess is provided in the other flat surface, and the other recess communicates with at least one of the first recess and the second recess.

9. An insert molded part comprising: an insert member; and a resin, having a structure formed by insert molding the insert member with the resin, a first recess and a second recess being provided on a predetermined surface of the insert member, the first recess and the second recess being connected, and the resin having entered the first recess and the second recess.

10. An insert member for an insert molded part, comprising a first recess and a second recess provided on a specified surface, the first recess and the second recess communicating with each other, and resin entering the first recess and the second recess by insert molding.

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