JP2017105150A - Insert molded article and manufacturing method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent rust from being generated inside a screw hole through applying plating treatment inside the screw hole by using a through-nut.SOLUTION: Provided is an insert molded article 10 which includes: a through-nut 20 in which a screw hole 21 is opened and plating treatment is applied on an entire surface including an inner face of the screw hole 21; a lid member (resin cap 30) which seals an opening on one side (upper-side opening 22) out of the openings on both sides of the through-nut 20; and a resin part 40 which covers the through-nut 20 and the lid member while having the opening on the other side (lower-side opening 23) of the through-nut 20 facing outer side. With such insert molded article 10, plating treatment can be applied inside the screw hole 21 by using the through-nut 20. Therefore, it is possible to prevent rust from being generated inside the screw hole 21 even when water enters into the screw hole 21.SELECTED DRAWING: Figure 6

Description

  The technology disclosed in this specification relates to an insert molded product using a through nut and a method for manufacturing the insert molded product.

  2. Description of the Related Art Conventionally, as a method for manufacturing an insert molded product using a nut, a method described in Japanese Patent Application Laid-Open No. 2005-288863 (the following Patent Document 1) is known. A stopper is detachably attached to the lower mold of the mold, a bag-like nut is screwed into the stopper, the mold is closed in that state, the cavity is filled with molten resin and solidified, and then the mold is opened. Separate the stop from the lower mold. Thereafter, by removing the stopper from the nut, an insert molded product using the nut is obtained.

JP 2005-288863 A

  However, since the nut is in a bag shape, the inside of the nut cannot be plated. For this reason, when water infiltrates into the nut, rust may be generated inside the nut. In order to plate the inside of the nut, it is necessary to use a through nut. However, if the through nut is used, the plating is peeled off by screwing into the stopper. Thus, under the present circumstances, the manufacturing method of the insert molded article using the penetration nut by which the plating process was performed inside has not been established, and development of the new manufacturing method was anxious.

  The insert-molded product disclosed in the present specification includes a through nut in which a screw hole is formed and plated on the entire surface including the inner surface of the screw hole, and an opening at both ends of the through nut. A lid member that closes the one side opening and a resin portion that covers the penetration nut and the lid member while facing the other side opening of the penetration nut to the outside.

  According to such an insert molded product, the inside of the screw hole can be plated by using a through nut. Therefore, even when water enters the inside of the screw hole, rust can be prevented from being generated inside the screw hole.

The insert molded product disclosed in the present specification may be configured as follows.
The lid member may be configured as a cap in which one side of the through nut is fitted.
Examples of the material of the cap include resin, rubber, and metal. If it is a resin cap, it can be manufactured at low cost. If it is a rubber cap, it will not be cracked by the injection pressure of the molten resin. If it is a metal cap, plate | board thickness can be made thin, the amount of resin which covers a penetration nut can be decreased, and the circumference | surroundings of a penetration nut can be reduced in size.

  Moreover, the said cover member is good also as a structure which is a rivet which assembled | attached the axial part to the said screw hole.

In order to manufacture such an insert molded product, the following method is preferable.
The method for manufacturing an insert-molded product disclosed in this specification is a method for manufacturing an insert-molded product using a through nut, wherein the upper end opening of the through nut faces the upper mold and the lower end opening is closed by the lower mold. A step of setting the through nut to the lower mold, a step of closing the upper end opening with a lid member, and after the mold is closed, the gate portion provided in the upper mold is melted toward the lid member. A step of injecting a resin and a step of opening the mold after the molten resin is solidified to form a resin portion and releasing the resin portion from the upper mold and the lower mold may be provided. .

  The reason for closing the opening of the through nut with the lid member is to prevent the molten resin from entering the through nut. Further, since the molten resin from the gate portion is injected toward the lid member, the lid member is pressed against the through nut by this injection pressure, and the through nut is pressed against the lower mold. Therefore, the sealing performance between the lid member and the through nut can be satisfied, and the sealing performance between the through nut and the lower mold can be satisfied. Furthermore, since the process of screwing the through nut to the lower mold is unnecessary, the number of molding steps can be reduced.

The gate portion may be arranged coaxially with the through nut.
If it does in this way, it can prevent that a penetration nut falls down by the injection pressure of molten resin.

The lower mold may include a positioning portion that positions the through nut so that the through nut and the gate portion are coaxially arranged.
If it does in this way, it will become easy to arrange a gate part and a penetration nut coaxially.

  According to the technique disclosed in this specification, plating can be performed inside the screw hole by using a through nut, and rust can be prevented from being generated inside the screw hole.

The front view of the insert molded product in Embodiment 1 AA line sectional view in FIG. Side view showing the state where the resin cap is assembled to the through nut Sectional view showing the through nut set in the lower mold Sectional view showing the upper mold and lower mold closed Cross-sectional view showing a state in which molten resin is injected from the gate portion into the resin cap to fill the cavity Sectional drawing which showed the manufacturing method of the insert molded product in Embodiment 2, Comprising: Sectional drawing corresponding to FIG. FIG. 6 is a cross-sectional view showing a method for manufacturing an insert-molded product according to Embodiment 3 and corresponding to FIG. It is sectional drawing of the insert molded product in Embodiment 4, Comprising: Sectional drawing corresponding to FIG. Side view showing the metal nut attached to the through nut Cross-sectional view showing a state in which molten resin is injected from the gate portion into the metal cap and the cavity is filled Sectional drawing which showed the state which set the penetration nut to the lower mold | type in the manufacturing method of the insert molded product in Embodiment 5. Sectional view showing the upper mold and lower mold closed Cross-sectional view showing a state in which molten resin is injected from the gate portion into the resin cap to fill the cavity Sectional drawing of the insert molded product in Embodiment 5, Comprising: Sectional drawing corresponding to FIG.

<Embodiment 1>
Embodiment 1 will be described with reference to FIGS. 1 to 6. The insert molded product 10 of this embodiment is a bolt fastening part for attaching a cover to a connector as shown in FIG. As shown in FIG. 2, the insert molded product 10 includes a through nut 20, a resin cap 30 in which the upper side of the through nut 20 is fitted, and a lower opening 23 of the through nut 20 facing the outside. 20 and a resin portion 40 that covers the resin cap 30.

  The through nut 20 has a cylindrical shape as a whole, and has a screw hole 21 penetrating in the vertical direction. A screw groove is formed in the screw hole 21 over the entire height, and a bolt can be screwed together. The entire surface of the through nut 20 is plated. For this reason, even if water permeates into the screw hole 21, rust does not occur inside the screw hole 21. Although not shown, serrations having a knurled shape are formed on the outer peripheral side surface of the through nut 20.

  The resin cap 30 is fitted to the main body portion 31 that is in close contact with the upper end surface 24 of the through nut 20, the inner fitting portion 32 that fits into the screw hole 21 from the upper opening 22 of the through nut 20, and the outer peripheral side of the through nut 20. And an external fitting portion 33 to be configured. The plate thickness (vertical dimension) of the main body 31 is larger than the plate thickness (diameter dimension) of the outer fitting portion 33. As shown in FIG. 3, a taper portion 34 is provided around the upper surface of the main body portion 31.

  The resin portion 40 includes a base plate portion 41 having a lower surface that is aligned with the lower end surface 25 of the through nut 20, and a peripheral wall portion 42 that rises upward from the outer peripheral side surface of the through nut 20 across the outer fitting portion 33 of the resin cap 30. The upper wall part 43 which covers the main body part 31 of the resin cap 30 from above is configured. An annular outer peripheral groove 44 is provided around the through nut 20 in the substrate portion 41. In addition, a shallow dish portion 45 that is shallower than the outer circumferential groove 44 is provided at the center of the upper surface of the upper wall portion 43.

  Next, a method for manufacturing the insert molded product 10 will be described. As shown in FIG. 4, the mold for molding the insert molded product 10 is composed of a lower mold 50 and an upper mold 60. The lower mold 50 is provided with a positioning protrusion 51 that fits into the screw hole 21 from the lower opening 23 of the through nut 20, and an outer peripheral rib 52 disposed around the positioning protrusion 51. The outer peripheral rib 52 is disposed along the outer peripheral side surface of the through nut 20 and serves as a portion for forming the outer peripheral groove 44 of the resin portion 40.

  The upper mold 60 has a recess 61 that is slightly larger than the through nut 20 to which the resin cap 30 is attached, and a gate portion 62 is provided on the back wall of the recess 61. The vicinity of the opening of the gate portion 62 is a stepped portion 63 that protrudes slightly downward. The stepped portion 63 is a portion for molding the shallow dish portion 45 of the resin portion 40.

  As shown in FIG. 5, when the mold is closed, a cavity C for filling the molten resin constituting the resin portion 40 is formed. The gate part 62 and the through nut 20 are coaxially arranged. Further, the upper surface of the main body portion 31 of the resin cap 30 is arranged perpendicular to the gate portion 62. For this reason, the molten resin injected from the gate portion 62 strikes the upper surface of the main body portion 31 and then flows into the lower mold 50 through the tapered portion 34 and the like.

  At this time, the resin cap 30 is strongly pressed against the through nut 20 by the injection pressure of the molten resin, and the through nut 20 is also strongly pressed against the lower mold 50. Therefore, the gap between the resin cap 30 and the through nut 20 is sealed, and the gap between the through nut 20 and the lower mold 50 is sealed. Therefore, the molten resin does not enter the screw hole 21.

  As shown in FIG. 6, after the molten resin is cooled and hardened after the cavity C is filled with the molten resin, the resin portion 40 is formed. When the mold is opened, the insert part 10 is obtained by removing the resin part 40 from the upper mold 60 and the lower mold 50.

  As described above, in the present embodiment, by using the through nut 20, the inside of the screw hole 21 can be plated. Therefore, it is possible to prevent rust from occurring inside the screw hole 21 even when water enters the screw hole 21.

  The lid member is a resin cap 30 in which one side of the through nut 20 is fitted, and the resin cap 30 can be manufactured at a low cost.

  The manufacturing method of the insert molded product 10 disclosed by this specification is a manufacturing method of the insert molded product 10 using the penetration nut 20, and the upper opening 22 of the penetration nut 20 faces the upper mold | type 60, and lower opening. The through nut 20 is set in the lower mold 50 so that the lower 23 is closed by the lower mold 50, the upper opening 22 is closed by the lid member (resin cap 30), and the upper mold 60 is closed after the mold is closed. The step of injecting the molten resin from the provided gate portion 62 toward the lid member, and after the molten resin is solidified to form the resin portion 40, the mold is opened to make the resin portion 40 the upper die 60 and the lower die 50. It is good also as a thing provided with the process to demold from.

  The reason for closing the opening (upper side opening 22) of the through nut 20 with the lid member is to prevent the molten resin from entering the through nut 20. In addition, since the molten resin from the gate portion 62 is injected toward the lid member, the lid member is pressed against the through nut 20 by the injection pressure, and the through nut 20 is pressed against the lower mold 50. Therefore, the sealing performance between the lid member and the through nut 20 can be satisfied, and the sealing performance between the through nut 20 and the lower mold 50 can be satisfied. Furthermore, since the process of screwing the through nut 20 to the lower mold 50 is not necessary, the number of molding steps can be reduced.

The gate portion 62 may be arranged coaxially with the through nut 20.
If it does in this way, it can prevent that penetration nut 20 falls down by the injection pressure of molten resin.

The lower mold 50 may include a positioning portion (positioning protrusion 51 and outer peripheral rib 52) for positioning the through nut 20 so that the through nut 20 and the gate portion 62 are coaxially arranged.
If it does in this way, it will become easy to arrange the gate part 62 and penetration nut 20 coaxially.

<Embodiment 2>
Next, Embodiment 2 will be described with reference to the drawing of FIG. The insert molded product 11 of the present embodiment uses a rivet 70 instead of the resin cap 30 in the insert molded product 10 of the first embodiment, and the other configurations are the same. The rivet 70 is made of metal and includes a shaft portion 71 that fits into the screw hole 21 and a head portion 72 that is in close contact with the upper end surface 24 of the through nut 20. The head 72 has a smaller diameter than the through nut 20. According to such a configuration, the rivet 70 is not cracked by the injection pressure of the molten resin.

<Embodiment 3>
Next, Embodiment 3 will be described with reference to the drawing of FIG. The insert molded product 12 of the present embodiment uses a rubber cap 80 instead of the resin cap 30 in the insert molded product 10 of the first embodiment, and the other configurations are the same. The rubber cap 80 has the same configuration as the resin cap 30, and includes a main body portion 81, an inner fitting portion 82, and an outer fitting portion 83. A plurality of lips 84 are provided on the inner peripheral surface of the outer fitting portion 83. According to such a configuration, the rubber cap 80 is not cracked by the injection pressure of the molten resin, and the sealing performance can be enhanced by the lip 84.

<Embodiment 4>
Next, a fourth embodiment will be described with reference to FIGS. 9 to 11. The insert molded product 13 of this embodiment uses a metal cap 90 instead of the resin cap 30 in the insert molded product 10 of Embodiment 1, and uses a stepped through nut 100 instead of the through nut 20. Other configurations are the same.

  Although the penetration nut 100 has the same configuration as that of the penetration nut 20 of the first embodiment, the difference from the penetration nut 20 is that a locking portion 106 having a stepped shape is provided on the upper side.

  The metal cap 90 is obtained by drawing a metal plate, and includes a main body portion 91 that is in close contact with the upper end surface 104 of the through nut 100, an internal fitting portion 92 that fits into the screw hole 101, and an outer peripheral side of the through nut 100. The outer fitting part 93 to be fitted is provided. The outer fitting portion 93 is provided with an annular protrusion 94 that protrudes toward the inner peripheral side. The protrusion 94 is locked to the locking portion 106 of the through nut 100. Thereby, the main body 91 is always in close contact with the upper end surface 104 of the through nut 100. On the other hand, the lower end surface 105 of the through nut 100 is in close contact with the lower mold 50 by the injection pressure of the molten resin injected from the gate portion 62 as in the first embodiment.

  Thus, if it is the metal cap 90, plate | board thickness can be made thin, the amount of resin which covers the penetration nut 100 can be decreased, and the circumference | surroundings of the penetration nut 100 can be reduced in size. However, in this embodiment, since the same mold as in the first to third embodiments is used, the insert molded product 13 has the same size as that in the first to third embodiments.

<Embodiment 5>
Next, a fifth embodiment will be described with reference to FIGS. The insert molded product 14 of the fifth embodiment is obtained by partially changing the configuration of the resin cap 30 in the insert molded product 10 of the first embodiment, and the other configurations are the same. With this change, although the configuration of the upper wall portion 111 of the resin portion 110 is partially changed, the resin cap 120 of the fifth embodiment is covered with the resin portion 110 and cannot be seen. The insert molded product 10 and the insert molded product 14 of the fifth embodiment are the same. In the insert molded product 14 of the fifth embodiment, the same reference numerals are used for the same configurations as those of the insert molded product 10 of the first embodiment, and the description thereof is omitted.

  In the resin cap 120 of the fifth embodiment, the top surface 121 of the main body portion 123 that receives the resin injected from the gate portion 62 has a conical shape. Since the gate portion 62 is disposed immediately above the vertex 122 of the top surface 121, the resin pressure received by the top surface 121 of the resin cap 120 when the resin injected from the gate portion 62 directly hits the vertex 122 is an embodiment. It can be reduced as compared with the one resin cap 30. Therefore, the top surface 121 of the resin cap 120 can be prevented from being damaged, and the resin can be prevented from flowing into the screw hole 21 of the through nut 20.

<Other embodiments>
The technology disclosed in the present specification is not limited to the embodiments described with reference to the above description and drawings, and includes, for example, the following various aspects.
(1) In the above embodiment, a through nut having a cylindrical shape is illustrated, but a through nut formed in a truncated cone shape and having a threaded hole may be used.

  (2) In the above embodiment, for the sake of convenience, a mold that is opened in the vertical direction by the upper mold 60 and the lower mold 50 is illustrated, but it can also be applied to various molds such as a mold that opens in the horizontal direction. It is.

  (3) Although the above embodiment exemplifies one having only one gate portion 62, a plurality of gate portions may be provided.

10, 11, 12, 13, 14 ... insert molded product 20, 100 ... penetrating nut 21, 101 ... screw hole 22, 102 ... upper side opening (one side opening)
23, 103 ... lower side opening (other side opening)
30, 120 ... Resin cap (lid member)
40, 110 ... resin part 50 ... lower mold 51 ... positioning protrusion (positioning part)
52 ... Outer peripheral rib (positioning part)
60 ... Upper die 62 ... Gate part 70 ... Rivet 71 ... Shaft part 80 ... Rubber cap 90 ... Metal cap

Claims (6)

A through-nut formed with a screw hole penetrating and plated over the entire surface including the inner surface of the screw hole;
A lid member for closing one side opening of both end openings of the through nut;
An insert-molded product comprising the through nut and a resin portion that covers the lid member while facing the other side opening of the through nut to the outside.   The insert molded product according to claim 1, wherein the lid member is a cap fitted on one side of the through nut.   The insert molded product according to claim 1, wherein the lid member is a rivet in which a shaft portion is assembled to the screw hole. A method of manufacturing an insert molded product using a through nut,
Setting the through nut to the lower mold so that the upper end opening of the through nut faces the upper mold and the lower end opening is closed by the lower mold;
Closing the upper end opening with a lid member;
After closing the mold, injecting molten resin from the gate portion provided in the upper mold toward the lid member;
After the molten resin is solidified to form a resin part, the mold is opened and the resin part is removed from the upper mold and the lower mold.   The said gate part is a manufacturing method of the insert molded article of Claim 4 arrange | positioned coaxially with the said penetration nut.   The method of manufacturing an insert-molded product according to claim 5, wherein the lower mold includes a positioning portion that positions the through nut so that the through nut and the gate portion are coaxially arranged.

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