Resin molded articles

Abstract

To provide a resin molded product that can increase rigidity and improve sealing function. [Solution] A resin molded product 10 having a function of sealing the space between it and the mating member 1 to be assembled, comprising a case body 11 and a flange portion 13 that protrudes outward from the peripheral edge portion 11aa of the side wall 11a of the case body and faces the mating member, wherein the flange portion has a circumferential groove 14 in which an elastic gasket 2 is provided and a rib portion 15 that is erected above the circumferential groove.

Description

Technical Field

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[0001] The present invention relates to a resin molded product having a function of sealing between mating members to be assembled.

Background Art

[0002] Conventionally, a resin molded product is known in which a gasket is accommodated in a groove formed on a surface facing a mating member, and the gasket seals between the mating members. For example, Patent Document 1 below discloses such a resin molded product in which a metal material for reinforcement is disposed on the back of the groove in which the gasket is accommodated or on the inner peripheral surface of the groove.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the resin molded product as described above, if the rigidity of the peripheral portion of the groove in which the gasket is accommodated is insufficient, the resin molded product may be deformed by the reaction force of the gasket or the internal pressure, and the sealing function may be deteriorated. In Patent Document 1, the rigidity of the groove can be increased by a metal material, and deformation of the groove in which the sealing member is accommodated can be suppressed, but there is a concern that the manufacturing man-hours and weight may increase. In addition, in order to increase the rigidity of the resin molded product, it is also conceivable to use a material with high rigidity or to form the portion where the groove is formed to be thick. However, as described above, in addition to the increase in weight, there are concerns such as an increase in the amount of resin used and an increase in the occurrence of sink marks and distortion in the molded product.

[0005] The present invention has been made in view of the above circumstances, and an object thereof is to provide a resin molded product capable of increasing rigidity and improving the sealing function.

Means for Solving the Problems

[0006] To achieve the above objective, the resin molded product configuration 1 of the present invention is a resin molded product having a function of sealing between it and a mating member to be assembled, comprising a case body and a flange portion that protrudes outward from the peripheral edge of the side wall of the case body and faces the mating member, wherein the flange portion has a circumferential groove in which an elastic gasket is provided and a rib portion that is erected above the circumferential groove.

[0007] The following description of embodiments reveals that the resin molded article according to the present invention may have the following dependent configurations. <Configuration 2> In configuration 1, the rib portion is a plate-like body and may be erected perpendicular to or oblique to the flange portion. <Structure 3> In configuration 1 or configuration 2, a second flange portion may be provided at the end of the rib portion on the side opposite to the mating member, and the flange portion may be arranged parallel to the flange portion. <Structure 4> In any one of configurations 1 to 3, the flange portion may have a fastening hole through which a fastener for fastening to the mating member is inserted. [Effects of the Invention]

[0008] Since the resin molded product of the present invention has the above-described structure, it is possible to increase rigidity and improve the sealing function. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic exploded perspective view showing an example of a resin molded product according to one embodiment of the present invention. [Figure 2] This is a schematic perspective view of a resin molded product according to the same embodiment, taken from the rear side. [Figure 3](a) is a cross-sectional view taken along the line XX in Figure 1, showing the state before it is fastened and integrated with the mating member by the fastener. (b) is a similar view to (a), showing the resin molded product shown in (a) after it has been fastened and integrated with the mating member by the fastener. [Figure 4] (a) is a cross-sectional view taken along the YY line in Figure 1, showing the state before it is fastened and integrated with the mating member by the fasteners. (b) is a similar view to (a), showing the resin molded product shown in (a) after it has been fastened and integrated with the mating member by the fasteners. [Figure 5] (a) and (b) are schematic perspective views of the resin molded product according to the modified example, and (c) is a schematic cross-sectional view of the resin molded product according to the modified example. [Figure 6] (a) is a schematic cross-sectional view of a resin molded product relating to Comparative Example 1, and (b) is a cross-sectional view of the resin molded product shown in (a) fastened to a mating member by a fastener. [Figure 7] This figure shows the results of deformation analysis tests of resin molded products in tabular format. [Modes for carrying out the invention]

[0010] An example of a resin molded product according to one embodiment of the present invention will be described below with reference to the drawings. Note that some of the detailed reference numerals used in other drawings have been omitted in some of the drawings.

[0011] The resin molded product 10 of this embodiment has the function of sealing the space between it and the mating member 1 to which it is assembled. The resin molded product 10 comprises a case body 11 and a flange portion 13 that protrudes outward from the peripheral edge 11aa of the side wall 11a of the case body 11 and faces the mating member 1. The flange portion 13 has a circumferential groove 14 in which an elastic gasket 2 is provided, and a rib portion 15 that is erected above the circumferential groove 14. A detailed explanation follows below. In the following explanation, the state in which the resin molded product 10 is assembled to the mating member 1 is used as a reference, with the mating member 1 side being the lower side in the vertical direction, and the opposite side, the side not facing the mating member 1, being the upper side in the vertical direction.

[0012] First, the resin molded product 10 according to this embodiment will be described with reference to Figures 1 to 4. The mating member 1 is not particularly limited in its configuration as long as it can be assembled with the resin molded product 10. For example, the mating member 1 may be a component (part) that is assembled to the resin molded product 10 which is configured as a water outlet or water inlet for an automobile. Alternatively, the resin molded product 10 and the mating member 1 may be the head cover and cylinder head of an automobile engine, etc. In the illustrated example, the mating member 1 is shown to have a substantially flat surface on the part facing the resin molded product 10, and is provided with multiple fastening holes 1a corresponding to the fastening holes 17 provided at the four corners of the flange portion 13 of the resin molded product 10. The mating member 1 is made of, for example, metal or resin, and has rigidity that prevents deformation due to the reaction force of the gasket 2.

[0013] The material of the molded resin product 10 is not particularly limited, but may be, for example, a thermoplastic resin such as polyethylene, polypropylene, ABS, acrylic, polycarbonate, polyamide, polyacetal, polyphenylene sulfide, or polyetheretherketone, or a fiber-reinforced resin containing reinforcing fibers such as carbon fiber or glass fiber. The molded resin product 10 may also have a metal component partially incorporated by insert molding or the like. The molded resin product 10 may be configured as a lid member that closes an opening provided in the mating member 1, and the case body 11 may not have a storage space 12. The molded resin product 10 may also be a piping member that is cylindrical with the case body 11 penetrating vertically.

[0014] The case body 11 in the illustrated example, which constitutes the resin molded product 10, is formed in a roughly rectangular box shape in plan view, and has side walls 11a surrounding all four sides and a top plate portion 11b provided at the upper end of the side walls 11a that closes the top of the case body 11. As shown in Figures 2, 4(a), and 4(b), the case body 11 has a storage space 12 that opens towards the mating member 1, and the storage space 12 is partitioned by the side walls 11a and the top plate portion 11b.

[0015] The flange portion 13 protrudes outward from the peripheral edge portion 11aa on the lower side of the side wall 11a of the case body 11 and is formed so as to surround the peripheral edge portion 11aa of the case body 11. When the resin molded product 10 is assembled to the mating member 1, the lower surface 13a of the flange portion 13 is formed so as to face the mating member 1. The flange portion 13 has a circumferential groove 14 in which an elastic gasket 2 is provided, a plurality of rib portions 15 erected above the circumferential groove 14, and a fastening hole 17 through which a fixture 3 for fastening to the mating member 1 is inserted. Further, the illustrated example shows that a second flange portion 16 arranged in parallel with the flange portion 13 is provided at the end portion 15a on the side opposite to the mating member of the rib portion 15. The thickness dimension of the flange portion 13 is not particularly limited but is set according to the depth dimension of the circumferential groove 14, and in the illustrated example, the thickness dimension of the flange portion 13 is set to be thicker (see Fig. 4(a) etc.) than the thickness dimension of the second flange portion 16.

[0016] The circumferential groove 14 is formed in a concave shape on the flat lower surface 13a of the flange portion 13 and is provided annularly along the circumferential direction of the flange portion 13. The annular gasket 2 shown in Figs. 1 and 2 is assembled to the circumferential groove 14. The circumferential groove 14 has a groove bottom 14a, groove walls 14b extending on both sides of the groove bottom 14a, and an opening portion 14c opening toward the mating member 1 as shown in Fig. 4(a) etc. In the vicinity of the fastening hole 17, the circumferential groove 14 is provided with a curved portion 14ba (see Fig. 2) so as to be located inside the fastening hole 17. The depth dimension of the circumferential groove 14 is set in consideration of the height dimension and the degree of compression of the gasket 2.

[0017] The shape and structure of the gasket 2 assembled to the circumferential groove 14 are not particularly limited. However, in the illustrated example, the gasket is configured to be elastically abutted against the groove wall 14b on the inner circumferential side of the circumferential groove 14 and fitted therein, and its cross-sectional shape is a substantially rectangular shape that is long in the vertical direction. The gasket 2 is formed in an annular shape along the circumferential direction of the circumferential groove 14, and has a corner portion 2a that is curved inward so as to conform to the curved portion 14ba of the circumferential groove 14 formed while avoiding the fastening holes 17. The gasket 2 is formed with a vertical dimension that is larger than the groove depth dimension of the circumferential groove 14 in its natural state before elastic deformation. The gasket 2 may be made of an elastic body, and examples of the material include rubber materials such as NBR, H-NBR, ACM, AEM, and FKM.

[0018] Above the circumferential groove 14, a plurality of rib portions 15 are erected in a direction orthogonal (vertical direction) to the flange portion 13. The rib portions 15 are provided so as to project forward (from the inside to the outside) from the side wall 11a of the case body 11 in accordance with the width dimension of the flange portion 13, and a plurality of rib portions 15 are provided at intervals in the circumferential direction of the flange portion 13, and a space portion 15b is provided between the rib portions 15. The rib portions 15 are arranged in a direction orthogonal to the longitudinal direction (circumferential direction) of the circumferential groove 14, and the inner end surface 15c of the rib portion 15 is integrally formed on the lower side of the side wall 11a and is configured to straddle the entire width direction of the circumferential groove 14 so as to exert an effect on suppressing the deformation of the flange portion 16. It is desirable that the rib portions 15 be arranged above the entire width direction of the circumferential groove 14 as shown in FIGS. 4(a) and 4(b). In the illustrated example, five rib portions 15 are provided between the fastening holes 17, 17 on the long side of the flange portion 13, and three rib portions 15 are provided between the fastening holes 17, 17 on the short side of the flange portion 13.

[0019] At the ends (upper ends) 15a of multiple rib portions 15 on the side opposite to the mating member 1, thin plate-shaped second flange portions 16 are provided, arranged parallel to the flange portion 13. The thickness of the second flange portion 16 is smaller than that of the flange portion 13, and its shape in plan view is substantially the same as that of the flange portion 13. At the four corners of the second flange portion 16, fastening holes 17 are provided through which fasteners 3 for fastening to the mating member 1 are inserted. These fastening holes 17 are through holes formed vertically from the second flange portion 16 to the flange portion 13, and a hollow cylindrical metal member 18 is embedded in the inner circumference of the fastening hole 17.

[0020] Figures 3(a) and 4(a) both show the state before the gasket 2 is fastened to the mating member 1 by the fastener 3. As shown here, at this stage, the gasket 2 is not compressed in the vertical direction, and the lower side of the gasket 2 protrudes from the circumferential groove 14. The gasket 2 is fitted into the circumferential groove 14 in elastic contact with the groove bottom 14a and the inner groove wall 14b, and a small gap is formed between it and the outer groove wall 14b.

[0021] Figures 3(b) and 4(b) both show the state after the resin molded product 10 has been fastened and integrated with the mating member 1 by the fastener 3. At this stage, the gasket 2 is compressed and deformed in the vertical and horizontal directions, and is interposed without any gaps between the groove bottom 14a and the mating member 1, sealing the space between the mating member 1 and the resin molded product 10, and the resin molded product 10 is assembled to the mating member 1. According to the resin molded product 10 of the above embodiment, since there are multiple rib portions 15 above the flange portion 13, stress concentration on the flange portion 13 can be mitigated when fastened and integrated, and the rigidity of the flange portion 13 can be increased. Therefore, deformation of the flange portion 13 due to the reaction force and internal pressure of the gasket 2 can be suppressed, and the sealing function of the resin molded product 10 can be improved. In addition, by having a structure in which there is a space 15b between the rib portions 15, it is possible to reduce the weight compared to a structure in which the thickness dimension of the flange portion 13 is increased in order to suppress deformation. Furthermore, even if the flange portion 13 is not made of a high-rigidity material, the rigidity can be increased, and insufficient compression of the gasket 2 can be prevented, thus eliminating concerns about increased costs due to material changes.

[0022] The structure and shape of the resin molded product 10 are not limited to the above embodiment, and Figures 5(a) to 5(c) show modified examples of the resin molded product 10. The explanation of the structure and effects of parts common to the above example will be omitted or simplified. The resin molded product 10A shown in Figure 5(a) differs from the above embodiment in that it does not have a second flange portion 16, but the other structures are the same as those of the above embodiment. Even without the second flange portion 16 as shown in Figure 5(a), the deformation of the flange portion 13 can be suppressed by providing the rib portion 15 above the circumferential groove 14 and in a direction perpendicular to it. This was confirmed in the deformation analysis test described later.

[0023] The resin molded product 10B shown in Figure 5(b) is an example in which the configuration of the case body 11, flange portion 13, second flange portion 16, etc. differs from the above embodiment. The case body 11 is formed in a cylindrical shape when viewed from above, and the outer shape of the flange portion 13 and the second flange portion 16 is formed in a substantially triangular shape when viewed from above. Fastening holes 17 are provided at the three corners of the flange portion 13 (second flange portion 16). The circumferential groove (not shown) is formed in a substantially triangular shape when viewed from above, similar to the shape of the flange portion 13. Even with this shape, since multiple rib portions 15 are erected above the circumferential groove, the amount of deformation of the flange portion 13 can be suppressed.

[0024] The resin molded product 10C shown in Figure 5(c) is an example that differs from the above embodiment in that multiple rib portions 15 are erected diagonally with respect to the flange portion 13. In this example, multiple rib portions 15 are provided in an alternating manner, with rib portions 15 inclined to one side of the circumferential direction of the flange portion 13 and rib portions 15 inclined to the other side of the circumferential direction, as one moves upward from the flange portion 13, forming a so-called truss structure. The lower end 15d of the rib portion 15 (towards the mating member) is positioned above the circumferential groove 14 and perpendicular to it, as in the above embodiment. Even with this shape, since multiple rib portions 15 are erected above the circumferential groove, the amount of deformation of the flange portion 13 can be suppressed.

[0025] <Deformation Analysis Test> Next, the deformation analysis test of the resin molded product will be explained with reference to Figures 6 and 7. First, two types of resin molded products 100 and 100A were prepared as comparative examples. Figures 6(a) and 6(b) are cross-sectional views showing one of them, the resin molded product 100 of Comparative Example 1. The resin molded product 100 has a case body 101, a housing space 102, a flange portion 103, a circumferential groove 104, and fastening holes 105, similar to the resin molded product 10 shown in Figure 1, etc. The resin molded product 100A of Comparative Example 2 differs in that it has a second flange portion 106 arranged parallel to the flange portion 103, and is an example without a rib portion. Two types of resin molded products 10A and 10 were prepared as examples. The resin molded product 10A of Example 1 is the same as the one shown in Figure 5(a). The resin molded product 10 of Example 2 is the same as the one shown in Figures 1 to 4.

[0026] Two types of deformation analysis tests were conducted to verify the deformation suppression effect. In comparative test 1, the deformation amount at the center of the width direction of the groove bottom of the circumferential grooves 14 and 140 was measured when the gasket 2 was attached to the circumferential grooves 14 and 140 and fastened together with the mating member 1 using the fastener 3, and the deformation reduction rate was calculated based on comparative example 1, which had the largest deformation amount. In comparative test 2, in addition to the conditions of comparative test 1, the deformation amount at the center of the width direction of the groove bottom of the circumferential grooves 14 and 140 was measured when internal pressure was applied to the housing spaces 12 and 102 of the case body 11 and 101, and the deformation reduction rate was calculated based on comparative example 1, which had the largest deformation amount. Figure 7 shows the deformation reduction rates for each test in a table; a larger value indicates a greater deformation suppression effect, and a smaller value indicates a larger deformation amount, similar to comparative example 1.

[0027] Figures 6(a) and 6(b) are schematic diagrams showing the deformation state of the resin molded product 100 of Comparative Example 1. Figure 6(a) shows the product before it is fastened and integrated with the mating member 1 by the fastener 3, and Figure 6(b) shows the product after it is fastened and integrated with the mating member 1 by the fastener 3. As shown here, without the rib portion, the flange portion 13 bends and deforms due to the compressive reaction force against the gasket 2. As the analysis and calculation results of Comparative Example 2 show, even when a second flange portion 106 is provided, the deformation suppression effect was not achieved.

[0028] <Deformation Analysis Test Results Summary> Examples 1 and 2 show a significant reduction in deformation compared to Comparative Examples 1 and 2 due to the provision of the rib portion 15. In comparative test 1, Example 1 showed a 37% reduction in deformation compared to Comparative Example 1, and Example 2 showed a 45% reduction compared to Comparative Example 1. In comparative test 2, Example 1 showed a 30% reduction in deformation compared to Comparative Example 1, and Example 2 showed a 35% reduction compared to Comparative Example 1.

[0029] Comparative Example 2 showed only a 4% reduction in deformation compared to Comparative Example 1 in Comparative Test 1, and a 5% reduction in deformation in Comparative Example 2. From these results, it was found that simply providing the second flange portion 106 has a smaller effect in suppressing the deformation of the flange portion 103 compared to the configuration with multiple rib portions 15 as in Examples 1 and 2. Also, comparing Example 1 and Example 2, the amount of deformation was reduced in Example 2, but a sufficient deformation suppression effect was confirmed even in Example 1.

[0030] The different configurations described in the above embodiments and their respective modifications may be modified, rearranged, or combined as appropriate and necessary. Furthermore, the resin molded products 10, 10A to 10C are not limited to the above configurations. For example, although an example of multiple rib portions 15 has been described, there may be only one. Specifically, the rib portion 15 may be provided only on a part of the flange portion 13, for example, one or more on the long side of the flange portion 13 as shown in Figure 1, or one or more on the short side. The rib portion 15 on the long side may be erected diagonally to the flange portion 13 as shown in Figure 5(c), and the rib portion on the short side may be erected at approximately 90 degrees to the upper surface of the flange portion 13 as shown in Figure 1, etc., or vice versa. The second flange portion 16 may also be placed only on the long side or only on the short side. The configuration and shape of the gasket 2 are not limited to the illustrated examples, and the cross-sectional shape may be formed as a circle or an ellipse, or it may have a bead. Furthermore, the second flange portion 16 may not be connected to the side wall 11a of the case body 11. Also, the resin molded product 10 and the mating member 1 are not limited to being fastened and assembled by fasteners 3. For example, one member may be provided with a locking claw that protrudes toward the other member, and the other member may be provided with a locking receiving portion that locks onto this locking claw. [Explanation of symbols]

[0031] 1. Opposing member 2 gaskets 3. Fasteners 10,10A~10C resin molded product 11 Case body 13 Flange section 14 Circumferential groove 15 Rib section 15a End portion (upper end portion) on the side opposite to the mating member 16. Second flange section 17 Fastening hole

Claims

1. A resin molded product having a function to seal the gap between it and the mating component to be assembled, The case comprises a case body and a flange portion that protrudes outward from the peripheral edge of the side wall of the case body and faces the mating member. The resin molded product is characterized in that the flange portion has a circumferential groove in which an elastic gasket is provided, and a rib portion erected above the circumferential groove.

2. In claim 1, The rib portion is a plate-like body, A resin molded product characterized by being erected perpendicular or obliquely to the flange portion.

3. In claim 1 or claim 2, A resin molded product characterized in that a second flange portion is provided at the end of the rib portion on the side opposite to the mating member, and is arranged parallel to the flange portion.

4. In claim 1 or claim 2, The resin molded product is characterized in that the flange portion has a fastening hole through which a fastener for fastening to the mating member is inserted.

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