Resin product and method of molding resin component

Abstract

To improve a mold releasing property of a first component, to increase a bonding strength between the first component and a second component, and to reduce the amount of resin required for the first component.SOLUTION: A resin product includes a first component 10 made of resin and a second component 20 made of resin. The first component 10 includes a first joint surface 13. The second component 20 includes a second joint surface 21 joined to the first joint surface 13. The first component 10 includes a contact surface 14 that is located on a side opposite to the first joint surface 13 in a facing direction Z, and that contacts with a jig that restrains the first component 10 when joining the first component 10 and the second component 20. The contact surface 14 includes a general portion, and a protruding portion 16 protruding in the facing direction Z more than the general portion. An outer side surface 17 located between the first joint surface 13 and the contact surface 14 in a portion of the first component 10 in which the protrusion portion 16 is provided is provided with a recess portion 18 that opens on the outer side surface 17.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a method for molding a resin product and a resin part. [Background technology]

[0002] 2. Description of the Related Art Conventionally, there is a resin product that includes a first part made of resin and a second part made of resin which are joined to each other. An example of such a resin product is an intake manifold for an internal combustion engine disclosed in Patent Document 1. The intake manifold disclosed in Patent Document 1 includes a surge tank and four branch pipes extending from the surge tank. The intake manifold includes a first part having an upper portion of the surge tank and an upper portion of the four branch pipes, and a second part having a lower portion of the surge tank and a lower portion of the four branch pipes. The first part has a first joint surface. The second part has a second joint surface joined to the first joint surface. The first part and the second part are formed by injection molding. The first part is located on the opposite side to the first joint surface in the opposing direction of the first part and the second part, and forms an abutment surface against which a jig that restrains the first part abuts when the first part and the second part are joined by a vibration welding method.

[0003] Further, conventionally, there is an intake manifold that has a protrusion such as a cylindrical boss or rib on the outer surface of the first component. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-25470 Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, when the first part is injection molded, a molten resin is injected into a cavity using a mold including a fixed mold having a molding surface for molding the inner surface of the first part, and a movable mold that is movable toward and away from the fixed mold and has a molding surface for molding the outer surface of the first part. If the outer surface of the first part has protrusions such as bosses or ribs, or if the shape of the outer surface is complex, the first part tends to cling to the movable mold retreating from the fixed mold when the mold is opened, which makes it difficult to release the first part from the movable mold. As a result, it becomes difficult to remove the first part from the movable mold. In this case, if the first part is forcibly removed from the movable mold, the first part may be damaged. In addition, if a release agent is applied to improve the release property of the first part, the cost increases.

[0006] Furthermore, in resin products, there is a demand for increasing the bonding strength between a first part and a second part and reducing the amount of resin used. [Means for solving the problem]

[0007] A resin product for solving the above problem comprises a first part made of resin and a second part made of resin, the first part having a first joining surface, and the second part having a second joining surface joined to the first joining surface, and when a direction in which the first joining surface and the second joining surface face each other is defined as an opposing direction, the first part is located on the opposite side of the first joining surface in the opposing direction, and has an abutment surface against which a jig that restrains the first part abuts when joining the first part and the second part, the abutment surface has a general portion and a protruding portion that protrudes in the opposing direction beyond the general portion, and an outer side surface located between the first joining surface and the abutment surface in a portion of the first part where the protruding portion is provided is provided with a recess that opens to the outer side surface.

[0008] According to this configuration, the outer surface of the first part is provided with a recess that opens to the outer surface. Therefore, the first part is provided slidably relative to the fixed mold and the movable mold, and the portion of the outer surface of the first part that includes the recess is molded by the molding surface of the slide mold, and the mold is opened in the following procedure, thereby preventing the above-mentioned inconvenience from occurring. That is, after the movable mold is retracted relative to the fixed mold and the slide mold, the slide mold is retracted relative to the fixed mold. When the movable mold is retracted, the convex portion of the molding surface of the slide mold is engaged with the recess of the first part, so that it is possible to prevent the first part from clinging to the movable mold and being unable to be removed from the movable mold.

[0009] However, when a first part and a second part are joined by vibration welding, if the jig slips relative to the first part, it is difficult to efficiently vibrate the first part with the jig. As a result, frictional heat generated between the joining surfaces is reduced, and the joining strength between the first part and the second part is likely to be insufficient. This problem is particularly noticeable when the contact surface of the first part includes many curved or inclined surfaces.

[0010] In this respect, according to the above configuration, when the first component and the second component are joined by vibration welding, the first component is restrained by the jig by abutting the abutting surface of the first component. Here, since the abutting surface is provided with a protruding portion that protrudes in the facing direction from the general portion, by engaging the jig with the protruding portion, it is possible to suppress the jig from slipping relative to the first component when vibrating the jig. This allows the first component to be vibrated efficiently, so that more frictional heat can be generated between the joining surfaces. Therefore, it is possible to increase the joining strength between the first component and the second component.

[0011] Furthermore, according to the above configuration, the recess is provided on the outer surface located between the first joint surface and the abutment surface of the portion of the first component where the protrusion is provided. The outer surface on which the recess is provided has a larger distance between the first joint surface and the abutment surface than other portions. Therefore, the reduction in strength of the first component caused by providing the recess is smaller than other portions. In addition, since there is no need to increase the amount of resin to suppress such a reduction in strength, the amount of resin required for the first component can be reduced.

[0012] In addition, a method of molding a resin part to solve the above-mentioned problem is a method of molding the first part that constitutes the resin product, and includes an injection process of injecting molten resin into a cavity formed by the first molding surface, the second molding surface, and the third molding surface using a molding mold that includes: a fixed mold having a first molding surface that molds an inner surface of the first part; a movable mold that is movable back and forth along the opposing direction relative to the fixed mold, and has a second molding surface that molds a portion of the outer surface of the first part that does not include the recess; and a sliding mold that is slidably movable relative to the fixed mold and the movable mold, and has a third molding surface that molds the portion of the outer surface of the first part that includes the recess; a movable mold retraction process of retracting the movable mold relative to the fixed mold and the sliding mold; and a sliding mold retraction process of retracting the sliding mold relative to the fixed mold after the movable mold retraction process.

[0013] According to this method, after the movable die is retracted relative to the fixed die and the sliding die, the sliding die is retracted relative to the fixed die. When the movable die is retracted, the convex portion of the molding surface of the sliding die is engaged with the concave portion of the first part, so that it is possible to prevent the first part from clinging to the movable die, which makes it difficult to remove the first part from the movable die.

[0014] Furthermore, according to the above method, the recess is provided on an outer surface located between the first joint surface and the abutment surface of the portion of the first component where the protrusion is provided. The outer surface on which the recess is provided has a larger distance between the first joint surface and the abutment surface than other portions. This makes it possible to suppress a decrease in strength of the first component due to the provision of the recess. In addition, since there is no need to increase the amount of resin to suppress such a decrease in strength, the amount of resin required for the first component can be reduced.

[0015] As described above, the above configuration and method can improve the releasability of the first component, increase the bonding strength between the first component and the second component, and reduce the amount of resin required for the first component. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 is a front view of an intake manifold according to one embodiment. [Diagram 2] FIG. 2 is an exploded perspective view of the intake manifold of FIG. [Diagram 3] FIG. 3 is a plan view of a first part that constitutes the intake manifold of FIG. [Figure 4] FIG. 4 is a front view of the first part of FIG. [Diagram 5] FIG. 5 is a bottom view of the first part of FIG. [Figure 6] FIG. 6 is a cross-sectional view taken along line 6-6 in FIG. [Figure 7] FIG. 7 is a cross-sectional view taken along line 7-7 in FIG. [Figure 8] 8(a) to 8(c) are cross-sectional views illustrating a method for molding the first component according to one embodiment. [Figure 9] FIG. 9 is an enlarged front view of the main part of FIG. [Figure 10] FIG. 10 is an enlarged perspective view of a main portion of the first component in FIG. [Figure 11] FIG. 11 is a cross-sectional view taken along line 11A-11A in FIG. [Figure 12]FIG. 12 is an enlarged perspective view of a main part of the first component according to the modified example. [Figure 13] FIG. 13 is a cross-sectional view taken along line 13A-13A in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, an embodiment of a resin product and a molding method for a resin part will be described with reference to Fig. 1 to Fig. 9. In this embodiment, the resin product is embodied as an intake manifold for an internal combustion engine. Also, the resin part is embodied as a first part 10 that constitutes the intake manifold.

[0018] As shown in FIGS. 1 and 2, the intake manifold is provided in an intake passage of an internal combustion engine. The intake manifold has a surge tank 100, and a first branch pipe 101, a second branch pipe 102, a third branch pipe 103, and a fourth branch pipe 104 that branch off and extend from the surge tank 100, respectively.

[0019] The first branch pipe 101 and the third branch pipe 103 extend from the surge tank 100 to the left side in Fig. 1, and then bend and extend downward in Fig. 1. The third branch pipe 103 is located lower than the first branch pipe 101 in Fig. 1.

[0020] The second branch pipe 102 and the fourth branch pipe 104 extend from the surge tank 100 to the right side in Fig. 1, and then bend and extend to the lower side in Fig. 1. The fourth branch pipe 104 is located lower than the second branch pipe 102 in Fig. 1.

[0021] The downstream ends of the branch pipes 101 to 104 are connected to intake ports of an internal combustion engine (not shown). The first branch pipe 101 is composed of a first part 10A and a second part 20, both of which are made of resin. The first part 10A and the second part 20 are halves of the first branch pipe 101 (see FIGS. 6 and 7).

[0022] The second branch pipe 102 is configured by a first part 10B and a second part 20, both of which are made of resin. The first part 10B and the second part 20 are half of the second branch pipe 102. The third branch pipe 103 and the fourth branch pipe 104 are both formed of a second part 20 and a third part 30. The second part 20 has a shape in which a half of the second branch pipe 102 and a half of the third part 30 are integrated together.

[0023] The intake manifold has a shape that is basically symmetrical in the left-right direction of Fig. 1. Therefore, in the following, the configuration on the left side of Fig. 1 will be described, and the configuration on the right side will not be described. Also, the first part 10A will be described simply as the first part 10.

[0024] <First part 10, second part 20> As shown in FIG. 5, the first component 10 has an annular first joining surface 13 . As shown in FIG. 2, the second component 20 has an annular second joining surface 21 joined to the first joining surface 13 .

[0025] Hereinafter, the direction in which the first bonding surface 13 and the second bonding surface 21 face each other is referred to as a facing direction Z. As shown in FIGS. 1 to 5, the first component 10 has an elongated shape that is long in a longitudinal direction X perpendicular to the facing direction Z.

[0026] The first component 10 has an outer surface 11 provided with a protrusion 12. The protrusion 12 includes a boss 12a and ribs 12b and 12c. The boss 12a is cylindrical and protrudes along the facing direction Z. In this embodiment, a plurality of bosses 12a are provided in the longitudinal direction X at intervals from one another.

[0027] The ribs 12b and 12c protrude along the opposing direction Z. In this embodiment, the multiple ribs 12b extend along a width direction Y perpendicular to both the opposing direction Z and the length direction X, and are spaced apart from one another in the length direction X (see FIG. 3). The multiple ribs 12c extend in the length direction X, and are spaced apart from one another in the width direction Y.

[0028] As shown in Figures 3, 4, 6, and 7, the first part 10 has an abutment surface 14 located on the opposite side to the first joint surface 13 in the facing direction Z. The abutment surface 14 extends in a substantially annular shape along the first joint surface 13. The abutment surface 14 is a surface that a jig 90 that restrains the first part 10 abuts against when the first part 10 and the second part 20 are joined by vibration welding. The abutment surface 14 has a general portion 15 and a protruding portion 16 that protrudes in the facing direction Z further than the general portion 15. The protruding portion 16 protrudes in the facing direction Z further than the general portion 15 adjacent to the protruding portion 16.

[0029] The protrusions 16 are located on both sides in the width direction Y. In this embodiment, the two protrusions 16 are provided at the same position in the length direction X. More specifically, the two protrusions 16 are provided at positions overlapping one boss 12a in the width direction Y. In this embodiment, the two protrusions 16 are provided at positions overlapping the boss 12a located at the rightmost side in FIG. 3 in the width direction Y.

[0030] 10 and 11, the protruding portion 16 extends in the extension direction of the general portion 15 adjacent to the protruding portion 16, i.e., in the longitudinal direction X. In detail, the protruding portion 16 has a planar end face 16a along both the longitudinal direction X and the width direction Y, and a pair of side faces 16b located between both ends of the end face 16a in the longitudinal direction X and the general portion 15 adjacent to the protruding portion 16. The entire side faces 16b are curved in an arc shape from the end face 16a to the general portion 15.

[0031] As shown in Figs. 3, 4, 6, and 7, the outer side surface 17 located between the first joint surface 13 and the abutment surface 14 in the portion of the first component 10 where the protrusion 16 is provided has a recess 18 that opens into the outer side surface 17. That is, the recess 18 is provided on the outer side surface 17 extending in the length direction X. The recess 18 is provided on each of the outer side surfaces 17 located on both sides in the width direction Y. The recess 18 is provided at a position overlapping with the boss 12a in the width direction Y. In this embodiment, two recesses 18 are provided at positions overlapping with the boss 12a located at the rightmost position in Fig. 3 in the width direction Y.

[0032] As shown in enlarged views in FIGS. 9, 10, and 11, the recess 18 extends in the extending direction of the protruding portion 16, that is, in the longitudinal direction X. Specifically, the cross-sectional shape of the recess 18 perpendicular to the width direction Y is a substantially rectangular shape that is long in the longitudinal direction X. The length of the recess 18 in the longitudinal direction X is smaller than the length of the protruding portion 16 in the longitudinal direction X. The entire recess 18 is located between both ends of the protruding portion 16 in the longitudinal direction X.

[0033] 6 and 9, the inner surface of the recess 18 is located on the second component 20 side in the facing direction Z and has a planar locking surface 18a extending along both the width direction Y and the length direction X. The inner surface of the recess 18 has an opposing surface 18b opposing the locking surface 18a. The opposing surface 18b is located between the tip surface 16a of the protruding portion 16 and the general portion 15 adjacent to the protruding portion 16 in the facing direction Z (see FIG. 9).

[0034] 6 and 7, the second component 20 has a joining surface 22 to be joined to the joining surface 31 of the third component 30. The joining surface 22 is provided on the opposite side to the second joining surface 21 in the facing direction Z.

[0035] <Third Part 30> As shown in FIG. 2, the third component 30 has an annular joining surface 31 . <Method of molding the first part 10> Next, a molding die 50 for molding the first component 10 and a molding method for the first component 10 using the molding die 50 will be described with reference to FIG.

[0036] <Mold 50> As shown in FIG. 8(a), the molding die 50 includes a fixed die 60, a movable die 70 movable forward and backward along the opposing direction Z relative to the fixed die 60, and a sliding die 80 movable relative to the fixed die 60 and the movable die 70.

[0037] The fixed mold 60 has a first molding surface 61 that molds the inner surface 19 of the first part 10 . The movable die 70 has a second molding surface 71 that molds the portion of the outer surface 11 of the first component 10 that includes the protrusion 12 but does not include the recess 18 .

[0038] The slide die 80 is provided so as to be slidable along the width direction Y. The slide die 80 has a third molding surface 81 which molds a portion of the outer surface 11 of the first component 10 that includes the recess 18 but does not include the protrusion 12. The third molding surface 81 has a protrusion 82 which molds the recess 18. The protrusion 82 has a flat portion 82a which molds the locking surface 18a of the recess 18 (see FIG. 8(b)).

[0039] When molding the first part 10, first, molten resin is injected from an injection device through a runner (all not shown) into the cavity 51 formed by the first molding surface 61, the second molding surface 71, and the third molding surface 81 of the closed molding die 50 (this is the injection process).

[0040] Subsequently, as shown in FIG. 8(b), the movable mold 70 is retreated relative to the fixed mold 60 and the sliding mold 80 (this is the movable mold retreat step). As shown in FIG. 8(c), after the movable mold retracting step, the sliding mold 80 is retracted relative to the fixed mold 60 (this is the sliding mold retracting step).

[0041] Next, the operation of this embodiment will be described. After the movable die 70 is retracted relative to the fixed die 60 and the sliding die 80, the sliding die 80 is retracted relative to the fixed die 60. When the movable die 70 is retracted, the convex portion 82 of the third molding surface 81 of the sliding die 80 is engaged with the concave portion 18 of the first component 10, so that it is possible to prevent the first component 10 from being unable to be removed from the movable die 70 due to the protrusion 12 clinging to the movable die 70.

[0042] However, when the first component 10 and the second component 20 are joined by vibration welding, if the jig 90 slips relative to the first component 10, it is difficult to efficiently vibrate the first component 10 with the jig 90. As a result, less frictional heat is generated between the joining surfaces 13, 21, and the joining strength between the first component 10 and the second component 20 is likely to be insufficient. This problem is particularly noticeable when the contact surface 14 of the first component 10 includes many curved surfaces and inclined surfaces, as shown in FIG. 9.

[0043] In this respect, according to the above configuration, when the first component 10 and the second component 20 are joined by the vibration welding method, the jig 90 is brought into contact with the abutment surface 14 of the first component 10, so that the first component 10 is restrained by the jig 90. Here, the abutment surface 14 is provided with the protruding portion 16 that protrudes in the facing direction Z more than the general portion 15. By engaging the jig 90 with the protruding portion 16, it is possible to prevent the jig 90 from slipping relative to the first component 10 when the jig 90 is vibrated. This allows the first component 10 to be vibrated efficiently, so that more frictional heat can be generated between the joining surfaces 13, 21. Therefore, the joining strength between the first component 10 and the second component 20 can be increased.

[0044] Furthermore, according to the above configuration, the recess 18 is provided on the outer side surface 17 located between the first joint surface 13 and the abutment surface 14 of the portion of the first component 10 where the protrusion 16 is provided. The outer side surface 17 where the recess 18 is provided has a larger distance between the first joint surface 13 and the abutment surface 14 than other portions. This makes it possible to suppress a decrease in strength of the first component 10 due to the provision of the recess 18. Also, since there is no need to increase the amount of resin to suppress such a decrease in strength, the amount of resin required for the first component 10 can be reduced.

[0045] Next, the effects of this embodiment will be described. (1) The resin product includes a first part 10 made of resin and a second part 20 made of resin. The first part 10 is located on the opposite side to the first joint surface 13 in the facing direction Z, and has an abutment surface 14 against which a jig 90 that restrains the first part 10 abuts when the first part 10 and the second part 20 are joined. The abutment surface 14 has a general portion 15 and a protruding portion 16 that protrudes in the facing direction Z beyond the general portion 15. A recess 18 that opens into the outer side surface 17 is provided on an outer side surface 17 located between the first joint surface 13 and the abutment surface 14 in a portion of the first part 10 where the protruding portion 16 is provided.

[0046] Such a configuration provides the above-mentioned effects, thereby improving the releasability of the first component 10 and increasing the bonding strength between the first component 10 and the second component 20. Also, the amount of resin required for the first component 10 can be reduced.

[0047] (2) The first component 10 has an elongated shape that is long in the longitudinal direction X. The recess 18 is provided on an outer surface 17 that extends in the longitudinal direction X. According to this configuration, the protrusions 12 are formed on the outer surface 17 extending in the longitudinal direction X, so that the recesses 18 can be provided at positions close to the protrusions 12. Therefore, it is possible to effectively prevent the protrusions 12 from clinging to the movable die 70, making it difficult to remove the first component 10 from the movable die 70.

[0048] (3) The recesses 18 are provided on the outer surfaces 17 located on both sides in the width direction Y perpendicular to both the facing direction Z and the length direction X, respectively. According to this configuration, when the movable die 70 is retracted, the convex portions 82 of the third molding surfaces 81 of the two slide dies 80 are respectively locked into the two concave portions 18 of the first part 10. This effectively prevents the protrusions 12 from clinging to the movable die 70, making it difficult to remove the first part 10 from the movable die 70.

[0049] (4) The protrusion 12 includes a cylindrical boss 12a. The recess 18 is provided at a position overlapping with the boss 12a in the width direction Y perpendicular to both the facing direction Z and the length direction X. According to this configuration, the recess 18 is provided at a position overlapping with the boss 12a in the width direction Y, that is, near the boss 12a that is likely to cling to the movable die 70 retreating from the fixed die 60 when the die is opened. This effectively prevents the boss 12a from clinging to the movable die 70, making it difficult to remove the first component 10 from the movable die 70.

[0050] (5) The inner surface of the recess 18 is located on the second component 20 side in the facing direction Z and has a flat locking surface 18a extending along both the width direction Y and the length direction X. According to this configuration, when the movable die 70 is retracted, the flat portion 82a of the convex portion 82 of the third molding surface 81 of the sliding die 80 comes into contact with the flat locking surface 18a. As a result, when the movable die 70 is retracted, the flat portion 82a of the convex portion 82 is accurately locked to the locking surface 18a of the recess 18, effectively preventing the protrusion 12 from clinging to the movable die 70 and making it difficult to remove the first component 10 from the movable die 70.

[0051] (6) The first component 10 and the second component 20 are halves of branch pipes 101, 102 that constitute an intake manifold of an internal combustion engine. Branch pipes 101, 102 that constitute an intake manifold of an internal combustion engine are formed by joining two half bodies together by vibration welding. In such half bodies, protrusions 12 such as bosses 12a and ribs 12b, 12c are provided on an outer surface 11. For this reason, when opening the mold, a problem is likely to occur in that the protrusions 12 cling to the movable mold 70 that is retreating from the fixed mold 60, making it difficult to remove the half body, which is the first part 10, from the movable mold 70.

[0052] In this regard, the above configuration can prevent the protrusions 12, such as the bosses 12a and the ribs 12b and 12c, from clinging to the movable die 70, making it difficult to remove the half body, which is the first part 10, from the movable die 70. In addition, a decrease in strength of the first part 10 due to the provision of the recesses 18 can be prevented.

[0053] (7) The molding method of the first part 10 includes an injection step of using a molding die 50 to inject molten resin into a cavity 51 formed by a first molding surface 61, a second molding surface 71, and a third molding surface 81. The molding method of the first part 10 includes a movable die retraction step of retracting the movable die 70 relative to the fixed die 60 and the sliding die 80, and a sliding die retraction step of retracting the sliding die 80 relative to the fixed die 60 after the movable die retraction step.

[0054] According to this method, it is possible to achieve the same effect as (1) above. <Modification> This embodiment can be modified as follows: This embodiment and the following modifications can be combined with each other to the extent that there is no technical contradiction.

[0055] The shape of the protrusion 16 is not limited to that exemplified in the above embodiment. For example, as shown in enlarged views in Fig. 12 and Fig. 13, a pair of side surfaces 16b may stand up from the general portion 15 along the opposing direction Z. In this case, the jig is more likely to engage with the protrusion 16 when the first component 10 and the second component 20 are joined by vibration welding. This makes it possible to further prevent the jig from slipping relative to the first component 10 when the jig is vibrated.

[0056] The locking surface 18a is not limited to a flat surface extending along both the width direction Y and the length direction X, but may be a curved or inclined surface. The cross-sectional shape of the recess 18 perpendicular to the width direction Y may be circular or elliptical.

[0057] The recess 18 may be provided at a position in the width direction Y that does not overlap with the boss 12a. The first component 10 does not necessarily have to have the boss 12a. Furthermore, the first component 10 does not necessarily have to have at least one of the ribs 12b, 12c.

[0058] The recess 18 may be provided on only one outer surface 17 in the width direction Y. A plurality of recesses 18 may be provided in the longitudinal direction X. In this case, it is preferable to change the number of protrusions 16 according to the number of recesses 18.

[0059] The recess 18 may be provided on the outer surface 17 located at the end in the longitudinal direction X. The first component 10 is not limited to being elongated, and may be, for example, polygonal or circular in plan view.

[0060] The first part 10 and the second part 20 are not limited to the halves of the branch pipes 101, 102 of the intake manifold. For example, the first part and the second part may constitute other intake pipes such as an inlet duct of an internal combustion engine, or may be embodied as a resin product other than an intake pipe of an internal combustion engine.

[0061] <Additional Notes> [Appendix 1] a first part made of resin and a second part made of resin, the first part having a first joining surface, the second part having a second joining surface joined to the first joining surface, the first part being located on the opposite side of the first joining surface in the opposing direction when a direction in which the first joining surface and the second joining surface face each other is defined as an opposing direction, the first part having an abutment surface against which a jig that restrains the first part comes into contact when joining the first part and the second part, the abutment surface having a general portion and a protruding portion that protrudes in the opposing direction beyond the general portion, and a recess that opens to the outer surface is provided on an outer surface of the first part located between the first joining surface and the abutment surface.

[0062] [Appendix 2] The resin product described in Appendix 1, wherein the first part has an elongated shape that is long in a length direction perpendicular to the opposing direction, and the recess is provided on the outer surface extending in the length direction.

[0063] [Appendix 3] The resin product described in Appendix 2, wherein the recesses are provided on both sides of the outer surface in a width direction perpendicular to both the opposing direction and the length direction.

[0064] [Appendix 4] The first component has an outer surface provided with a protrusion, The resin product according to claim 2 or 3, wherein the protrusion includes a cylindrical boss, and the recess is provided at a position overlapping with the boss in a width direction perpendicular to both the opposing direction and the length direction.

[0065] [Appendix 5] The resin product according to any one of Appendix 2 to Appendix 4, wherein an inner surface of the recess has a planar locking surface located on the second component side in the opposing direction and extending along both a width direction and the length direction perpendicular to both the opposing direction and the length direction.

[0066] [Appendix 6] 6. The resin product according to any one of claims 2 to 5, wherein the first part and the second part are halves of branch pipes that constitute an intake manifold of an internal combustion engine.

[0067] [Appendix 7] a movable mold provided to be slidable relative to the fixed mold and the movable mold, and having a third molding surface that molds a portion of the outer surface of the first part that includes the recess; an injection step of injecting molten resin into a cavity formed by the first molding surface, the second molding surface, and the third molding surface using a molding mold provided with: a fixed mold having a first molding surface that molds an inner surface of the first part; a movable mold that is provided to be movable forward and backward along the opposing direction relative to the fixed mold, and has a second molding surface that molds a portion of the outer surface of the first part that does not include the recess; and a sliding mold that is provided to be slidable relative to the fixed mold and the movable mold, and has a third molding surface that molds the portion of the outer surface of the first part that includes the recess; a movable mold retracting step of retracting the movable mold relative to the fixed mold and the sliding mold; and a sliding mold retracting step of retracting the sliding mold relative to the fixed mold after the movable mold retracting step. [Explanation of symbols]

[0068] 10, 10A, 10B...First part 11...External surface 12…Protrusion 12a…Boss 12b, 12c…Rib 13…First joint surface 14...Abutment surface 15…General section 16...Protrusion 16a...Pointed end surface 16b...side 17...Outer surface 18…Recess 18a...Latching surface 18b...Opposing surface 19…Inner 20…Second part 21…Second joint surface 22…Joint surface 30…Third part 31…Joint surface 50…Mold 51…Cavity 60…Fixed type 61…First molding surface 70…Movable type 71…Second molding surface 80...Slide type 81…Third molding surface 82…Convex part 82a…Plane part 90…Jig 100…Surge tank 101…First branch pipe 102...Second branch pipe 103…Third branch pipe 104…4th branch pipe X: Length direction Y: Width direction Z: Opposite direction

Claims

1. A first part made of resin; A second component made of resin, the first component has a first joining surface; the second component has a second joining surface joined to the first joining surface, When a direction in which the first bonding surface and the second bonding surface face each other is defined as a facing direction, the first part is located on an opposite side to the first joining surface in the opposing direction and has a contact surface with which a jig that restrains the first part comes into contact when the first part and the second part are joined, The contact surface has a general portion and a protruding portion protruding in the opposing direction beyond the general portion, a recess that opens to the outer surface is provided on an outer surface located between the first joint surface and the abutment surface in a portion of the first component where the protrusion is provided; Resin products.

2. The first component has an elongated shape that is long in a length direction perpendicular to the opposing direction, The recess is provided on the outer surface extending in the longitudinal direction. The resin product according to claim 1.

3. The recesses are provided on the outer surfaces located on both sides in a width direction perpendicular to both the opposing direction and the length direction, The resin product according to claim 2.

4. The first component has an outer surface provided with a protrusion, The protrusion includes a cylindrical boss, The recess is provided at a position overlapping with the boss in a width direction perpendicular to both the facing direction and the length direction. The resin product according to claim 2.

5. an inner surface of the recess is located on the second component side in the facing direction and has a planar locking surface extending along both the width direction and the length direction perpendicular to both the facing direction and the length direction; The resin product according to claim 2.

6. The first part and the second part are each a half of a branch pipe constituting an intake manifold of an internal combustion engine. The resin product according to claim 2.

7. A method for molding the first part constituting the resin product according to any one of claims 1 to 6, comprising the steps of: a fixed mold having a first molding surface for molding an inner surface of the first part; a movable mold provided to be movable back and forth along the opposing direction relative to the fixed mold, the movable mold having a second molding surface that molds a portion of an outer surface of the first component that does not include the recess; an injection process of injecting molten resin into a cavity formed by the first molding surface, the second molding surface, and the third molding surface using a molding die including a slide die that is slidably provided with respect to the fixed die and the movable die and has a third molding surface that molds a portion of an outer surface of the first component that includes the recess; a movable die retracting step of retracting the movable die relative to the fixed die and the sliding die; and a slide die retracting step of retracting the slide die relative to the fixed die after the movable die retracting step. A method for molding plastic parts.

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