Resin molded article and first component

Abstract

Disclosed is a resin molded article in which a variation in the melting state of melting portions of melt ribs provided in a first component is suppressed, thereby promoting uniformity of the molten state of the melting portions and promoting uniformity of the strength of parts where the melting portions are welded to a second component.　A resin molded article 10 comprises a first component 22 made of a synthetic resin and a second component 24 made of a synthetic resin, wherein: the first component 22 includes embedded portions 26 that are embedded in and integrated with the second component 24, recessed grooves 28 that open in surfaces 62, 84 of the embedded portions 26 that face the second component 24, and melt ribs 32 that protrude into the recessed grooves 28 and that each have a melting portion 30; and the melting portions 30 are welded to the second component 24 that fills the recessed grooves 28.

Description

Resin molded product and first component

[0001] The present disclosure relates to a resin molded product and a first component.

[0002] In Patent Document 1, in a connector component which is a kind of resin molded product, a melt rib is provided which protrudes outward from the main body portion of an inner component which is a first component around which an outer portion which is a second component is disposed by integral molding, and a part of the molten portion provided on the melt rib melts during the molding of the outer portion and adheres to the resin body of the outer portion. A configuration is disclosed.

[0003] Japanese Unexamined Patent Application Publication No. 2019-93681

[0004] In the structure of Patent Document 1, since the melt rib is provided so as to protrude outward from the main body portion of the inner component, when molding the outer portion, based on the difference in the separation distance from the gate position of the melt rib, the melt rib is exposed to the flow of the molten resin. Variations are likely to occur in the exposure time. As a result, the melting condition of the molten portion of the melt rib tends to be non-uniform, and there is a possibility that a difference may occur in the fixing strength between the molten portion and the resin body of the outer portion due to the variation in the melting condition.

[0005] Therefore, a resin molded product and a first component are disclosed which can suppress variations in the melting condition of the molten portion of the melt rib provided in the first component, promote the uniformity of the melting state of the molten portion, and promote the uniformity of the strength at the welding site of the molten portion to the second component.

[0006] The resin molded product of the present disclosure includes a first component made of synthetic resin and a second component made of synthetic resin, and the first component has an embedded portion which is embedded in the second component and integrated, a concave groove which opens on the opposing surface of the embedded portion to the second component, and a melt rib which protrudes in the concave groove and has a molten portion, and the molten portion is welded to the second component which fills the concave groove.

[0007] The first component of this disclosure is a synthetic resin component that is inserted into a second component made of synthetic resin and integrated with the second component, and comprises an embedded portion embedded in the second component, a groove opening on the surface of the embedded portion facing the second component, and a melt rib protruding from the groove with its tip being a melting portion, wherein the melting portion is melted when the second component is molded.

[0008] According to the resin molded product of this disclosure, variations in the degree of melting of the melted portion of the melt rib provided in the first component can be suppressed, thereby promoting uniformity of the melted state of the melted portion and promoting uniformity of the strength at the welding site of the melted portion to the second component.

[0009] According to the first component of this disclosure, in a resin molded product, variations in the degree of melting of the melted portion of the melt rib provided in the first component can be suppressed, thereby promoting uniformity of the melted state of the melted portion and promoting uniformity of the strength at the welding site of the melted portion to the second component.

[0010] Figure 1 is a plan view showing an electrical junction box, which is a resin molded product according to Embodiment 1. Figure 2 is a longitudinal cross-sectional view showing an enlarged view of the main part of the section II-II in Figure 1. Figure 3 is a longitudinal cross-sectional view showing an enlarged view of the main part of the section III-III in Figure 1.

[0011] <Description of Embodiments of the Disclosure> First, embodiments of the Disclosure will be listed and described. The resin molded product of the Disclosure comprises (1) a first component made of synthetic resin and a second component made of synthetic resin, wherein the first component has an embedded portion that is embedded in and integrated with the second component, a groove opening on the surface of the embedded portion facing the second component, and a melt rib protruding from the groove and having a molten portion, wherein the molten portion is welded to the second component that fills the groove.

[0012] In the resin molded product of this embodiment, the first part has an embedded portion that is embedded in the second part and is integrated with the second part. Furthermore, the embedded portion is provided with a groove that opens to the surface facing the second part, and the molten portion of the melt rib protruding into the groove is welded to the second part that fills the groove. As a result, a region is formed between the embedded portion of the first part and the opposing surface of the second part where the molten portion has melted and solidified with the second part, thereby advantageously achieving the securing of bonding strength between the first and second parts and the securing of sealing performance between the opposing surfaces.

[0013] In particular, since the melt rib is provided protruding from a groove that opens onto the surface of the embedded portion facing the second component, it is less affected by the flow velocity of the molten resin during injection molding of the second component. Therefore, compared to the conventional structure in which the melt rib of the embedded portion directly protrudes from the surface facing the second component, it is possible to advantageously reduce the problem of variations in the degree of melting of the molten portion depending on the distance from the molding gate position of the second component. As a result, the uniformity of the melt state of the molten portion can be promoted, and the strength at the welding site of the molten portion to the second component can be made uniform. In addition, the degree of freedom in setting the gate position during molding of the second component is improved.

[0014] In addition, since the resin constituting the second component is filled into the groove provided in the embedded portion of the first component, the groove can absorb the strain caused by the mutual displacement of the first and second components due to temperature changes during use of the resin molded product. This reduces stress concentration at the welding site to the second component in the molten portion, and stably maintains the adhesion and sealing properties of the first and second components.

[0015] (2) In (1) above, it is preferable that the embedded portion of the first component is arranged to surround the periphery of the waterproof area of ​​the second component, the groove is formed in an annular shape surrounding the periphery of the waterproof area of ​​the second component, and the molten portion is welded to the second component filling the groove over the entire circumference of the groove. When the embedded portion of the first component is arranged to surround the waterproof area of ​​the second component, the molten portion of the melt rib provided in the annular groove that opens to the embedded portion of the first component and surrounds the periphery of the waterproof area is welded to the second component filling the groove over the entire circumference of the groove. As a result, the watertightness of the waterproof area of ​​the second component can be ensured by welding the molten portion to the second component without having to arrange a sealing member around the waterproof area of ​​the second component. This makes it possible to simplify and miniaturize the resin molded product while ensuring the watertightness of the waterproof area.

[0016] (3) In (1) or (2) above, it is preferable that the melt rib protrudes from the bottom surface of the groove toward the opening side. Since the melt rib protrudes from the bottom surface of the groove toward the opening side, it is less affected by the flow velocity of the molten resin during injection molding of the second part, and the uniformity of the bonding strength of the molten portion of the melt rib to the second part can be further advantageously achieved.

[0017] (4) In (3) above, it is preferable that the protruding dimension of the melt rib is 2 / 3 or less of the depth dimension of the groove. Since the protruding dimension of the melt rib toward the opening side from the bottom surface of the groove is kept to 2 / 3 or less of the depth dimension of the groove, the influence of the flow velocity of the molten resin during injection molding of the second part can be further advantageously reduced, and the uniformity of the bonding strength of the welded portion of the melt rib to the second part can be further advantageously achieved.

[0018] (5) In the above (2), it is preferable that the second component includes a case for housing a circuit board, and the first component includes a connector mounting portion provided in the opening of the case which serves as the waterproof area, and the connector mounting portion has a hood portion that protrudes above the case and an embedded portion that extends in a flange shape on the base end side of the hood portion, with the embedded portion surrounding the periphery of the opening. When the second component of the resin molded product is a case for housing a circuit board and the first component is a connector mounting portion provided in the opening of the case, the resin molded product with waterproof function according to this embodiment can be applied to an electrical junction box. In this case, by using the flange-shaped portion on the base end side which bears the load applied to the connector mounting portion as the embedded portion, an annular groove surrounding the periphery of the opening can be advantageously provided. Furthermore, by providing the welding portion of the melt rib's molten section to the second component along the entire circumference of the groove surrounding the opening, waterproof performance can be reliably and stably achieved around the entire circumference of the opening, between the opposing surfaces of the case and the embedded section, by the welding portion of the molten section to the second component.

[0019] The first component of the present disclosure is (6) a first component made of synthetic resin which is inserted into and integrated with a second component made of synthetic resin, and having an embedded portion which is embedded in the second component, a groove which opens on the surface of the embedded portion which faces the second component, and a melt rib which protrudes from the groove and whose tip is a melting portion, wherein the melting portion is melted when the second component is molded.

[0020] According to the first part of this embodiment, it has an embedded portion that is embedded in the second part and is integrated with the second part. Furthermore, the embedded portion is provided with a groove that opens to the surface facing the second part, and a melt portion is provided in the melt rib protruding from the groove that melts during the molding of the second part. Therefore, by inserting the first part and injection molding the second part so that the embedded portion is embedded, a resin molded product according to any one of the embodiments (1) to (5) above can be provided, and the same effects and advantages can be enjoyed.

[0021] <Details of Embodiments of the Disclosure> Specific examples of the resin molded articles of the Disclosure will be described below with reference to the drawings. However, the Disclosure is not limited to these examples and is intended to include all modifications within the meaning and scope of the Claims, as indicated by the Claims.

[0022] <Embodiment 1> Hereinafter, an electrical junction box 10, which is a resin molded product of Embodiment 1 of the present disclosure, will be described with reference to Figures 1 to 3. This electrical junction box 10 includes a case 14 in which a circuit board 12 is housed. Specifically, the case 14 is composed of an upper case 16 and a lower case 18, and the case 14 is constructed by covering the upper opening 20 of the lower case 18 with the upper case 16. The electrical junction box 10 can be positioned in any orientation, but in the following description, "upper" refers to the upper part in Figure 2, "lower" refers to the lower part in Figure 2, "front" refers to the left in Figure 1, "rear" refers to the right in Figure 1, "left" refers to the upper part in Figure 1, and "right" refers to the lower part in Figure 1. In addition, for multiple identical components, reference numerals may be assigned to only some of the components, while the reference numerals for other components may be omitted.

[0023] <Resin molded product (electrical junction box 10)> The electrical junction box 10 comprises a first component 22 made of synthetic resin and a second component 24 made of synthetic resin. The first component 22 has an embedded portion 26 that is embedded in and integrated with the second component 24, a groove 28 that opens on the surface of the embedded portion 26 facing the second component 24 (outer surfaces 62, 84 described later), and a melt rib 32 that is provided protruding into the groove 28 and has a molten portion 30. The molten portion 30 of this melt rib 32 is welded to the second component 24 that is filled in the groove 28, thereby welding the first component 22 and the second component 24 to each other. Note that the embedded portion 26 of the first component 22 does not need to be embedded in the second component 24 as a whole, and a part of the embedded portion 26 may be exposed to the outside from the second component 24.

[0024] In particular, in Embodiment 1, the electrical connection box 10 (especially the upper case 16) comprises a plurality of first components 22, each of which includes a plurality of connector mounting portions 38 (described later) and a terminal block 40. The second component 24 includes a case 14 that houses the circuit board 12, and specifically includes an upper bottom wall portion 42 and a lower case 18 in the upper case 16 (described later). Therefore, in Embodiment 1, the second component 24 is composed of a plurality of members.

[0025] The circuit board 12 housed in the electrical connection box 10 (case 14) is not limited to any particular type, but any known circuit board such as a rigid printed circuit board or a flexible printed circuit board (FPC) may be used, and an electrical circuit (not shown) is printed on at least one surface of the circuit board 12 in the thickness direction. Furthermore, through-holes 34 that penetrate the circuit board 12 in the thickness direction are formed at predetermined locations on the circuit board 12. The method of fixing the circuit board 12 to the case 14 is not limited to any particular type.

[0026] <Upper Case 16> The upper case 16 comprises a plurality of connector mounting portions 38 and one terminal block 40, which are first components 22. The upper case 16 also includes an upper bottom wall portion 42 that is substantially flat in shape as a whole, and as described above, the second component 24 is formed including the upper bottom wall portion 42. Each first component 22 (each connector mounting portion 38 and terminal block 40) is fixed to the upper bottom wall portion 42. In Embodiment 1, the upper bottom wall portion 42 comprises a plurality of waterproof areas 44 on which each first component 22 is provided. Each waterproof area 44 is a part of the upper bottom wall portion 42 where watertight sealing is required, and the embedded portion 26 of the first component 22 is arranged to surround the waterproof area 44, and the embedded portion 26 and the second component 24 are fixed together so that water does not enter the waterproof area 44. Specifically, the waterproof area 44 is composed of an opening 46 to which each connector mounting portion 38 is fixed, and a through portion 48 to which the terminal block 40 is fixed.

[0027] <Lower Case 18> The lower case 18 is generally box-shaped, opening upward (having an upper opening 20), and comprises a generally flat bottom wall portion 52 that extends horizontally (in a direction perpendicular to the vertical direction), and a lower peripheral wall portion 54 that protrudes upward from the outer peripheral edge of the bottom wall portion 52. Therefore, the upper opening 20 is formed by the upper end of the lower peripheral wall portion 54. The method of fixing the upper case 16 and the lower case 18 is not limited.

[0028] The lower case 18 can be formed from a rigid material such as metal or synthetic resin. When the lower case 18 is made of synthetic resin, materials such as polyphenylene sulfide (PPS) or polybutylene terephthalate (PBT) are preferably used. Furthermore, when the lower case 18 is made of synthetic resin, it may be reinforced with glass fibers or the like.

[0029] <First Component 22 (Connector Mounting Section 38)> In Embodiment 1, as described above, some of the first component 22 is composed of connector mounting sections 38. Each connector mounting section 38, as shown in Figure 2, includes a hood section 60 that protrudes upward from the case 14 (particularly the upper bottom wall section 42 of the upper case 16) and an embedded section 26 that spreads out in a flange-like manner at the base end (lower end) of the hood section 60. In Embodiment 1, the hood section 60 is substantially cylindrical and continuous around the entire circumference, and the embedded section 26 at the base end (lower end) of the hood section 60 is formed as a substantially annular portion that protrudes outward around the entire circumference. In particular, in Embodiment 1, each hood section 60 is formed in a substantially rectangular annular shape in plan view, and each embedded section 26 is also formed in a substantially rectangular annular shape in plan view. A groove 28 that opens downward is formed on the lower surface of the embedded section 26, which is thus substantially rectangular annular. As will be described later, in the connector mounting portion 38, the outer surface 62 of the embedded portion 26, including the inner circumferential surface, lower surface, and outer circumferential surface of the embedded portion 26, forms the opposing surface between the embedded portion 26 and the second component 24. Therefore, the groove 28 opens to the surface of the embedded portion 26 that faces the second component 24.

[0030] In Embodiment 1, the connector mounting portion 38 has a terminal retaining wall 66 that divides the hood portion 60 into an inward (downward) side and an outward (upward) side of the case 14. The connector mounting portion 38 also includes connection terminals 68 that penetrate the terminal retaining wall 66 and protrude to the inward (downward) side and outward (upward) side of the case 14. In Embodiment 1, a plurality of connection terminals 68 are provided, and each connection terminal 68 is fixedly held against the terminal retaining wall 66. Each connection terminal 68 is arranged in alignment in the front-to-back and left-to-right directions on the inner circumference of the hood portion 60.

[0031] Specifically, in the vertically intermediate portion of the hood portion 60, a terminal retaining wall 66 is provided that extends horizontally on the inner circumference side of the hood portion 60. The intermediate portion of each connection terminal 68 extending in the vertical direction is embedded in the terminal retaining wall 66, with one end (lower end) of each connection terminal 68 protruding downward from the terminal retaining wall 66, and the other end (upper end) of each connection terminal 68 protruding upward from the terminal retaining wall 66. In other words, when the upper case 16, which includes each connector mounting portion 38, is fixed to the lower case 18 to form the case 14 (electrical connection box 10), one end (lower end) of each connection terminal 68 protrudes inward from the case 14, and the other end (upper end) of each connection terminal 68 protrudes outward from the case 14.

[0032] In Embodiment 1, the connector mounting portion 38 is formed as an integrally molded product equipped with each connection terminal 68. Specifically, when molding the connector mounting portion 38, injection molding is performed with each connection terminal 68 set as an insert within the molding cavity of the connector mounting portion 38, thereby forming the connector mounting portion 38 as an integrally molded product equipped with each connection terminal 68. As a result, each connection terminal 68 is fixedly held against the terminal holding wall 66. The resin material constituting the connector mounting portion 38 (hood portion 60 and embedded portion 26) is not limited as long as it is rigid, but materials such as PPS and PBT are preferably used, similar to the lower case 18, and may be reinforced with, for example, glass fiber.

[0033] Furthermore, the other end (upper end) of each connection terminal 68 is located on the inner circumference side of the hood portion 60 and protrudes upward. As a result, each connector mounting portion 38 constitutes a male connector, and when a female connector (not shown) which is the mating connector is attached to each connector mounting portion 38, each connection terminal 68 and the connection terminal of the female connector are electrically connected.

[0034] <Grooves 28> Each groove 28 is an annular groove that extends continuously around the entire circumference in the circumferential direction. In Embodiment 1, each groove 28 is formed in the radially intermediate portion of the lower surface of each embedded portion 26. As mentioned above, each embedded portion 26 is provided surrounding the periphery of the waterproof area 44, and therefore each groove 28 is provided surrounding the periphery of each waterproof area 44. In particular, in Embodiment 1, each groove 28 opens downward and has a rectangular cross-sectional shape with an upper bottom surface 72 which is the bottom surface and an inner surface consisting of both sides.

[0035] <Melt Rib 32> As described above, a melt rib 32 having a molten portion 30 protrudes from the groove 28. The melt rib 32 is integrally formed with the upper bottom wall portion 42 and has a shape that gradually or stepwise narrows towards the protruding tip. When the first part 22 and the second part 24 are fixed together as described later, when the second part 24 is molded with the first part 22 as an insert, the molten resin material of the second part 24 flows into the groove 28, causing the protruding tip portion of the melt rib 32 to melt and become integrated with the second part 24. Therefore, the protruding tip portion of the melt rib 32 is the molten portion 30. The molten portion 30 is welded to the second part 24 that fills the groove 28 around the entire circumference of the groove 28. In Figures 2 and 3, the melt rib 32 before the melting of the molten portion 30 is shown by a dashed line, and the melt rib 32 after the melting of the molten portion 30 is shown by a solid line. As shown in Figures 2 and 3, in Embodiment 1, the melt rib 32 of the molten portion 30 before melting has a substantially triangular cross-section and protrudes downward from the upper bottom surface 72 of the groove 28.

[0036] Furthermore, in Embodiment 1, the melt rib 32 is continuously provided within the groove 28 over the entire circumference in the circumferential direction, and is formed in an annular shape in plan view (projection in the axial direction). In particular, in Embodiment 1, two of these annular melt ribs 32 are provided within the groove 28, and the two melt ribs 32, 32 are provided substantially adjacent to each other on the inner and outer circumferential sides.

[0037] Furthermore, the downward protrusion dimension T (see Figure 2) of each melt rib 32 before melting in the molten portion 30 is preferably such that the protruding tip does not protrude below the lower opening of the groove 28, for example, it is preferably 2 / 3 or less of the depth dimension D (see Figure 2) of the groove 28. In Embodiment 1, the protrusion dimension T of each melt rib 32 is set to about 1 / 2 of the depth dimension D of the groove 28.

[0038] <First component 22 (terminal block 40)> In Embodiment 1, as described above, one of the first components 22 is composed of a terminal block 40. This terminal block 40 has a connecting terminal 76 having one end connected to a circuit board 12 and the other end having a terminal fastening portion 74, and a terminal base 78 that holds the connecting terminal 76 with the terminal fastening portion 74 exposed above the through portion 48 which is a waterproof area 44.

[0039] Specifically, in Embodiment 1, the connection terminal 76 is bent in a roughly L-shape, with one end extending downward and connected to the circuit board 12. The other end of the connection terminal 76 spreads horizontally, forming a terminal fastening portion 74 that is roughly rectangular in plan view. A bolt insertion hole 80 is formed in the central part of the terminal fastening portion 74, penetrating in the thickness direction (vertical direction), and the shaft of a stud bolt 82 positioned below the terminal fastening portion 74 protrudes upward through the bolt insertion hole 80. Thus, when a mating terminal (not shown) is connected to the connection terminal 76, the shaft of the stud bolt 82 is inserted through a bolt insertion hole provided in the mating terminal, and a nut is fastened to the stud bolt 82, thereby overlapping the mating terminal and the terminal fastening portion 74 and electrically connecting them.

[0040] The terminal fastening portion 74 and the stud bolt 82 are supported on the terminal base 78, and as described above, the terminal fastening portion 74 is exposed upward, and the shaft portion of the stud bolt 82 protrudes upward. The terminal base 78 is substantially rectangular in plan view and has a predetermined thickness. The embedded portion 26 is formed by the peripheral edge of the base end (lower end) of the terminal base 78. Specifically, the base end (lower end) of the terminal base 78 protrudes outward relative to the upper portion, and the embedded portion 26 is formed by this outwardly protruding portion. This embedded portion 26 is formed in a continuous ring shape over the entire circumference in the circumferential direction.

[0041] Furthermore, a groove 28 opening downwards is formed on the lower surface of the terminal base 78. This groove 28 has the same shape as the groove 28 in the connector mounting portion 38 and is an annular groove that extends continuously around the entire circumference. In addition, two melt ribs 32, 32 protruding downwards are provided within this groove 28, similar to the connector mounting portion 38. This groove 28 may be provided in the embedded portion 26, or it may be provided on the inner circumference side of the embedded portion 26. As will be described later, in the terminal block 40 as well, the outer surface 84 of the embedded portion 26, including the inner surface, lower surface, and outer surface of the embedded portion 26, constitutes the opposing surface between the embedded portion 26 and the second component 24, so the groove 28 opens to the surface of the embedded portion 26 that is facing the second component 24.

[0042] In Embodiment 1, the terminal block 40 is formed as an integrally molded product equipped with connection terminals 76 and stud bolts 82. Specifically, when molding the terminal block 40, the connection terminals 76 and stud bolts 82 are inserted into the molding cavity of the terminal block 40 during injection molding, thereby forming the terminal block 40 as an integrally molded product equipped with connection terminals 76 and stud bolts 82. As a result, the connection terminals 76 and stud bolts 82 are fixedly held with respect to the terminal base 78. The resin material constituting the terminal base 78 is not limited as long as it is rigid, but materials such as PPS or PBT are preferably used, similar to the connector mounting portion 38, and it may be reinforced with, for example, glass fiber.

[0043] <Second Component 24> As described above, the second component 24 is composed of the upper bottom wall portion 42 and the lower case 18 in the upper case 16. In the upper bottom wall portion 42, an opening 46 as a waterproof area 44 penetrating the upper bottom wall portion 42 in the vertical direction is formed at the portion where each connector mounting portion 38 as the first component 22 is fixed. Also, in the upper bottom wall portion 42, a through hole 48 as a waterproof area 44 penetrating the upper bottom wall portion 42 in the vertical direction is formed at the portion where the terminal block 40 as the first component 22 is fixed. Since the embedded portions 26 in each first component 22 are provided so as to surround the periphery of each waterproof area 44, the embedded portion 26 provided in each connector mounting portion 38 surrounds the periphery of the opening 46, and the embedded portion 26 provided in the terminal block 40 surrounds the periphery of the through hole 48.

[0044] <Waterproof Area 44 (Opening 46)> The opening 46 as the waterproof area 44 has a shape substantially corresponding to the connector mounting portion 38 in a plan view and is substantially rectangular. The opening 46 is formed by penetrating the upper bottom wall portion 42 in the vertical direction, and a housing recess 88 for housing the embedded portion 26 provided at the lower end portion of the connector mounting portion 38 is formed at the peripheral edge portion of the opening 46. As also shown in FIG. 2, the housing recess 88 has a rectangular cross-sectional shape substantially corresponding to the embedded portion 26 and is an annular recess continuous over the entire circumference in the circumferential direction around the opening 46. In short, when the first component (connector mounting portion 38) and the second component (upper bottom wall portion 42) are fixed, each embedded portion 26 is housed in each housing recess 88, and the outer surface 62 of each embedded portion 26 (including the inner circumferential surface, lower surface, and outer circumferential surface of the embedded portion 26) and the inner surface 90 of each housing recess 88 (including the inner circumferential side surface, bottom surface, and outer circumferential side surface of the housing recess 88) are the opposing surfaces of the embedded portion 26 and the second component 24. Note that in the state where the first component 22 and the second component 24 are fixed and each embedded portion 26 is housed in the housing recess 88, the upper surface of each embedded portion 26 is exposed to the outside.

[0045] <Waterproof Area 44 (Penetration 48)> The penetration 48, which serves as the waterproof area 44, is the portion in the upper bottom wall 42 through which the longitudinal middle portion of the connection terminal 76 provided on the terminal block 40 is inserted, and is rectangular in shape in plan view, corresponding to the connection terminal 76. Around the penetration 48, a housing recess 92 is formed to accommodate the terminal base 78 and the embedded portion 26. In short, when the first component (terminal block 40) and the second component (upper bottom wall 42) are fixed together, the terminal base 78 and the embedded portion 26 are housed in the housing recess 92, and the outer surfaces 84 of the terminal base 78 and the embedded portion 26 (including the lower surfaces of the terminal base 78 and the embedded portion 26 and the outer peripheral surface of the embedded portion 26) and the inner surface 94 of the housing recess 92 (including the inner peripheral side surface, bottom surface and outer peripheral side surface of the housing recess 92) are the opposing surfaces of the embedded portion 26 and the second component 24. When the first part 22 and the second part 24 are fixed together and the terminal base 78 and the embedded part 26 are housed in the receiving recess 92, the upper portion of the terminal base 78 and the upper surface of the embedded part 26 are exposed to the outside.

[0046] <Manufacturing Method for Resin Molded Product (Electrical Connection Box 10)> The following describes a specific example of the manufacturing method for the electrical connection box 10. However, the manufacturing method for the electrical connection box 10 is not limited to the description below.

[0047] First, in the first component molding process, the first component 22, namely the connector mounting portion 38 and the terminal block 40, is formed by injection molding. In Embodiment 1, since the connector mounting portion 38 is formed integrally with each connection terminal 68, a connector mounting portion 38 equipped with each connection terminal 68 is obtained. Also, since the terminal block 40 is formed integrally with the connection terminals 76, a terminal block 40 equipped with the connection terminals 76 is obtained by the first component molding process.

[0048] Subsequently, in the second component forming process, a plurality of first components 22 (each connector mounting portion 38 and terminal block 40) manufactured in the first component forming process are set as insert parts in the cavity for forming the upper bottom wall portion 42 that constitutes a part of the second component 24, and the upper bottom wall portion 42 is formed by injection molding. As a result, a housing recess 88 is formed so as to cover the periphery of the embedded portion 26 in each connector mounting portion 38, and a housing recess 92 is formed so as to cover the periphery of the terminal block base 78 and the embedded portion 26 in the terminal block 40, and the second component 24 (upper bottom wall portion 42) integrally including each first component 22 is formed. When forming this upper bottom wall portion 42, since the molten upper bottom wall portion 42 is filled into the cavity for forming with each first component 22 inserted, the molten upper bottom wall portion 42 flows into the groove 28 in each first component 22. Then, due to the heat of the molten upper bottom wall portion 42, the molten portion 30, which is the protruding tip portion of each melt rib 32, melts, and each melt rib 32 (each embedded portion 26) and the upper bottom wall portion 42 are melted and adhered together. As a result, the upper case 16 is completed.

[0049] Then, for example, the circuit board 12 is approached from below to the upper case 16 manufactured as described above and fixed with screws. As a result, in the upper case 16, one end (lower end) of each connection terminal 68 and connection terminal 76 protruding downward is inserted into each through hole 34 in the circuit board 12. Each connection terminal 68 and connection terminal 76 inserted into each through hole 34 may be electrically connected to the circuit board 12 by solder or the like not shown. Further, with respect to the separately formed lower case 18, the upper case 16 with the circuit board 12 assembled is approached from above, and in a state where the upper opening 20 of the lower case 18 is covered with the upper case 16, for example, the upper case 16 and the lower case 18 are fixed with screws. As a result, the entire second component 24 is formed by the upper bottom wall portion 42 and the lower case 18, and the case 14 in which the circuit board 12 is housed inside is formed, and the electrical connection box 10 is completed.

[0050] According to the resin molded product (electrical connection box 10) of Embodiment 1, which has the structure described above, a groove 28 is provided between a first component 22 made of synthetic resin and a second component 24 made of synthetic resin, and the first component 22 and the second component 24 are more firmly welded together by utilizing the melt ribs 32 that protrude into the groove 28. More specifically, the first component 22 has an embedded portion 26 that is embedded in the second component 24, and the grooves 28 and melt ribs 32 are provided between the opposing surfaces (outer surfaces 62, 84 and inner surfaces 90, 94) of the embedded portion 26 and the second component 24, and the molten portion 30 in each melt rib 32 is melted by the heat of the second component 24 that is filled into each groove 28, thereby welding the first component 22 and the second component 24 together. As a result, the first component 22 and the second component 24 are more firmly fixed together, and the intrusion of water through them can be more reliably prevented.

[0051] In particular, when molding the second part 24, the molten second part 24 (upper bottom wall portion 42) flows into each groove 28 in each first part 22. Within each groove 28, changes in the flow velocity of the molten upper bottom wall portion 42 are less likely to occur, and the molten portion 30 in each melt rib 32 within each groove 28 melts almost uniformly. As a result, gaps are less likely to form between the first part 22 and the second part 24 after the electrical connection box 10 is manufactured, and the above-mentioned water intrusion prevention effect is achieved even more reliably. As a result, the degree of freedom in setting the gate position when molding the second part 24 can also be improved. Furthermore, since each melt rib 32 is provided within each groove 28, even when the resin molded product (electrical connection box 10) expands or contracts due to changes in the external environment temperature, stress does not concentrate at the protruding tip of each melt rib 32. This strain can be received by each groove 28, making it even less likely for gaps to form between the first part 22 and the second part 24, especially at the formation positions of each melt rib 32.

[0052] The first component 22 (each connector mounting portion 38 and terminal block 40) is arranged to surround the waterproof area 44 (each opening 46 and through portion 48) of the second component 24 (upper bottom wall portion 42), with each groove 28 being formed in an annular shape, and each melt rib 32 within each groove 28 also being formed in an annular shape. Therefore, when the second component 24 is molded, the molten portion 30 of each melt rib 32 melts and integrates with the second component 24 around the waterproof area 44, thereby effectively preventing water from entering around the waterproof area 44 where a waterproof structure is required.

[0053] Each melt rib 32 is provided projecting downward from the bottom surface (upper bottom surface 72) of each groove 28 toward the opening side. This makes it possible to make the timing of contact between the molten upper bottom wall 42 and each melt rib 32 when the molten second part 24 (upper bottom wall portion 42) flows into each groove 28 approximately equal. As a result, the molten portion 30 in each melt rib 32 can be melted approximately uniformly, and problems such as the occurrence of gaps between the first part 22 and the second part 24 due to uneven melting of the molten portion 30 can be suppressed even more reliably.

[0054] In particular, since the protruding dimension T of each melt rib 32 is 2 / 3 or less of the depth dimension D of each groove 28, compared to, for example, the case where the protruding tip of each melt rib 32 is located near the opening of each groove 28, the timing difference in contact between the molten upper bottom wall 42 and each melt rib 32 when the molten upper bottom wall 42 is filled into the molding cavity of the upper bottom wall 42 can be made smaller. As a result, the influence of the molten upper bottom wall 42 can be suppressed more, and the molten portion 30 can be melted substantially uniformly, thereby more firmly fixing the first part 22 and the second part 24.

[0055] In Embodiment 1, a plurality of first components 22 are provided, some of which are connector mounting portions 38, and the second component 24 is the upper bottom wall portion 42 of the upper case 16 and the lower case 18 that constitute the case 14. Thus, an electrical connection box 10 equipped with a plurality of connector mounting portions 38 is constructed as a resin molded product comprising the first components 22 and the second components 24. That is, when providing the connector mounting portions 38 in the electrical connection box 10, an opening 46 that penetrates in the thickness direction is formed in the upper bottom wall portion 42, and by fixing the connector mounting portion 38 (embedded portion 26) to this opening 46 which serves as a waterproof area 44, the intrusion of water through the opening 46 can be effectively prevented.

[0056] <Modifications> Although Embodiment 1 has been described in detail above as a specific example of the present disclosure, the present disclosure is not limited by this specific description. Modifications, improvements, etc., to the extent that they can achieve the purpose of the present disclosure are included in the present disclosure. For example, the following modifications of the embodiments are also included in the technical scope of the present disclosure.

[0057] (1) In the above embodiment 1, the first component 22 was made up of connector mounting parts 38 and terminal blocks 40, and the second component 24 was made up of an upper bottom wall part 42 and a lower case 18, and the resin molded product comprising these first component 22 and second component 24 was made up of an electrical connection box 10, but the present invention is not limited to this embodiment. The specific embodiments of the first component, the second component and the resin molded product comprising them are not limited. Also, in the above embodiment 1, the second component 24 (upper bottom wall part 42) was integrally molded with the first component 22 as an insert, but the present invention is not limited to this embodiment. Furthermore, in the resin molded product according to this disclosure, a waterproof area is not essential. That is, the embedded part, groove and melt rib in the first component do not need to be provided in the part of the second component that particularly requires watertight sealing.

[0058] For example, the second component may consist only of the upper bottom wall portion, and the upper case may be a resin molded product comprising the first component (each connector mounting portion and terminal block) and the second component. Alternatively, the first component may be the upper bottom wall portion, or an integrated upper bottom wall portion and lower case. In these cases, the upper bottom wall portion, which is the first component, may be provided with an embedded portion and a groove, with a melt rib provided in the groove, while the connector mounting portion, which is the second component, may have a receiving recess that accommodates the embedded portion.

[0059] (2) In the above embodiment 1, each connection terminal 68 and each connector mounting portion 38 were integrally molded so that each connection terminal 68 was fixedly held by the terminal retaining wall 66 of each connector mounting portion 38. However, each connection terminal and each connector mounting portion may be formed separately, and each connection terminal may be press-fitted into a through hole provided in the terminal retaining wall of each connector mounting portion so that each connection terminal is fixedly held by the terminal retaining wall of each connector mounting portion. Alternatively, each connection terminal does not have to be fixedly held by the terminal retaining wall, and each connection terminal may be separated from the inner circumferential surface of the terminal retaining wall by a gap.

[0060] (3) In the embodiment 1 described above, each melt rib 32 protruded from the upper bottom surface 72 of each groove 28, but the embodiment is not limited to this. Each melt rib only needs to protrude from at least one of the upper bottom surface and both sides that constitute the inner surface of each groove. Furthermore, the shape and number of each melt rib are not limited, and for example, they may be cylindrical or polygonal prism shapes that taper in stages, or one or more annular melt ribs may be provided in the groove.

[0061] (4) The circuit board is not limited to being fixed to the upper case, but may also be fixed to the lower case. Furthermore, the upper case and the lower case are not limited to being fixed together by screws, but may also be fixed together by, for example, a known locking mechanism.

[0062] 10 Electrical junction box 12 Circuit board 14 Case 16 Upper case 18 Lower case 20 Upper opening 22 First component 24 Second component 26 Embedded section 28 Groove 30 Melting section 32 Melt rib 34 Through hole 38 Connector mounting section 40 Terminal block 42 Upper bottom wall section 44 Waterproof area 46 Opening 48 Through section 52 Bottom wall section 54 Lower peripheral wall section 60 Hood section 62 Outer surface (opposing surface) 66 Terminal retaining wall 68 Connection terminal 72 Upper bottom surface (bottom surface) 74 Terminal fastening section 76 Connection terminal 78 Terminal base 80 Bolt insertion hole 82 Stud bolt 84 Outer surface (opposing surface) 88 Retaining recess 90 Inner surface (opposing surface) 92 Retaining recess 94 Inner surface (opposite side)

Claims

1. A resin molded product comprising a first part made of synthetic resin and a second part made of synthetic resin, wherein the first part has an embedded portion that is embedded in and integrated with the second part, a groove opening on the surface of the embedded portion facing the second part, and a melt rib protruding from the groove and having a molten portion, the molten portion being welded to the second part that fills the groove.

2. The resin molded product according to claim 1, wherein the embedded portion of the first component is arranged to surround the periphery of the waterproof area of ​​the second component, the groove is formed in an annular shape surrounding the periphery of the waterproof area of ​​the second component, and the molten portion is welded to the second component filling the groove over the entire circumference of the groove.

3. The resin molded article according to claim 1 or claim 2, wherein the melt rib is provided protruding from the bottom surface of the groove toward the opening side.

4. The resin molded article according to claim 3, wherein the protruding dimension of the melt rib is 2 / 3 or less of the depth dimension of the groove.

5. The resin molded product according to claim 2, wherein the second component includes a case for housing a circuit board inside, the first component includes a connector mounting portion provided in an opening of the case which serves as a waterproof area, the connector mounting portion having a hood portion that protrudes above the case and an embedded portion that extends in a flange-like manner toward the base end of the hood portion, and the embedded portion surrounds the periphery of the opening.

6. A first part made of synthetic resin, which is inserted into a second part made of synthetic resin and integrated with the second part, the first part having an embedded portion embedded in the second part, a groove opening on the surface of the embedded portion facing the second part, and a melt rib protruding from the groove with its tip being a melting portion, wherein the melting portion is melted during the molding of the second part.

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