JP2020020400A - Insert nut and secondary molding method of the same - Google Patents

Abstract

To provide an insert nut which can inhibit damage to a mold and a screw part of a nut.SOLUTION: An insert nut 10 formed as a primary molded item includes: a metallic nut 11 which has an opening 15a of a screw hole 15 at the upper surface 12 side and includes a bottomed screw hole which is closed at the lower surface 14 side; and a resin part 20 which exposes the opening 15a of the screw hole 15 of the nut 11 and has a side surface part 21 covering an outer peripheral surface 13 of the nut 11 and a bottom surface part 23 covering the lower surface 14 of the nut 11. A polygonal protruding part 24 is formed at the bottom surface part 23 of the resin part 20. At the upper surface 12 side of the nut 11 of the side surface part 21 of the resin part 20, multiple cutouts 22 are formed at positions facing positions of apexes 24a of the polygonal protruding part 24.SELECTED DRAWING: Figure 4

Description

  The present invention relates to, for example, an insert nut used as a fastening member of an electronic control unit or the like and a secondary molding method thereof.

  As this kind of insert nut, for example, there is one disclosed in Patent Document 1. As shown in FIGS. 9 and 10, the insert nut 1 is provided with a screw hole 2a of a cap nut 2 made of metal and having a screw hole with a bottom as an insert part in a component installation recess 4 of a mold 3 on a fixed side. In the state where the cap nut 2 is sucked and held by the protruding pipe portion 5 by inserting it into the protruding pipe portion 5 and housing it in the component installation recess 4 and setting the pipe hole 6 of the protruding pipe portion 5 to a negative pressure, After the movable mold 8 is moved to close both the molds 3 and 8, a molten resin (molding material) R is injected from the gate 7 of the fixed mold 3 into the closed cavity 9. The solidification (hardening) of the molten resin R results in insert molding.

JP-A-2006-321061 JP 2013-194818 A

  However, in the conventional insert nut 1, the screw hole 2a of the metal cap nut 2 is inserted and held in the protruding pipe portion 5 of the metal mold 3, so that the molding 3 The protruding pipe portion 5 is liable to wear, and the inclination and looseness of the cap nut 2 held by the protruding pipe portion 5 increase. That is, there is a concern that the holding force may decrease due to air leakage from the pipe hole 6 and the cap nut 2 may be inclined.

  Further, when the cap nut 2 is set in the mold 3, there is a possibility that the plating of the screw hole 2a may be scraped or the screw portion of the screw hole 2a may be damaged.

  Then, this invention was made in order to solve the said subject, and it aims at providing the insert nut which can suppress the damage to the thread part of a metal mold | die and a nut, and its secondary molding method. I do.

  The present invention has an opening of a screw hole on the upper surface side, and a metal nut with a bottomed screw hole closed on the lower surface side, and exposes the opening of the screw hole of the nut, and exposes the outer peripheral surface of the nut. An insert nut as a primary molded product including a covering side portion and a resin portion having a bottom portion covering a lower surface of the nut, wherein a polygonal protrusion is formed on the bottom portion of the resin portion. A plurality of cutouts are formed on the side surface of the resin portion on the upper surface side of the nut at positions opposed to the vertices of the polygonal protrusion.

  Further, the present invention is a secondary molding method of an insert nut as the primary molded product, comprising a receiving recess having a bottom surface on which an upper surface of the nut is arranged and a positioning portion fitted into each of the notches. Using a lower mold and an upper mold that forms a filling space together with the lower mold to form a molded resin part that is integrally molded with the protrusion of the resin part; While inserting, the setting step of arranging the upper surface of the nut on the bottom surface of the housing recess, and positioning the protruding portion of the resin portion in the filling space; And a molding step of molding the molding resin portion so as to cover the protruding portion.

  ADVANTAGE OF THE INVENTION According to this invention, since the position control and holding | maintenance of an insert component in the accommodation recessed part of a metal mold | die are performed in a resin part, damage to the screw part of a metal mold and a nut can be suppressed.

It is a perspective view showing a bag-like nut (insert part) before insert molding of one embodiment of the present invention. It is a perspective view of the insert nut (primary molded article) which insert-molded the said bag-shaped nut. It is a top view of the said insert nut. It is a perspective view at the time of setting the said insert nut in the accommodation recessed part of a lower metal mold | die. It is sectional drawing which shows the state which performs the secondary molding (final molding) of the said insert nut in an upper and lower metal mold. It is a perspective view at the time of releasing the above-mentioned secondary molded insert nut (secondarily molded product) from the upper and lower molds. It is a perspective view of the insert nut released. It is the perspective view which looked at the insert nut which carried out the above-mentioned secondary molding from the upper surface side. It is sectional drawing of the metal mold | die which shows the state in the middle of insert molding the metal cap nut as a conventional insert part. It is sectional drawing of the metal mold | die which shows the state just after completion of the said conventional insert molding.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a perspective view showing a bag-shaped nut (insert part) before insert molding according to an embodiment of the present invention, and FIG. 2 is a perspective view of an insert nut (primary molded product) obtained by insert-molding the bag-shaped nut. , FIG. 3 is a top view of the insert nut, FIG. 4 is a perspective view when the insert nut is set in the accommodation recess of the lower mold, and FIG. 5 is subjected to secondary molding (final molding) of the insert nut in the upper and lower molds. FIG. 6 is a cross-sectional view showing the state, FIG. 6 is a perspective view of the secondary molded insert nut (secondarily molded product) when it is released from the upper and lower molds, and FIG. 7 is a perspective view of the released insert nut. 8 is a perspective view of the insert nut as viewed from above.

  As shown in FIGS. 2 and 3, the insert nut 10 has an opening 15 a of a female screw hole (screw hole) 15 on the upper surface 12, and has a bottomed screw hole whose lower surface 14 is closed and made of metal. 1 and a cylindrical side surface 21 that covers the outer peripheral surface 13 of the nut 11 and a bottom surface that covers the lower surface 14 of the nut 11 by exposing the opening 15 a of the female screw hole 15 of the nut 11 shown in FIG. The insert nut 10 ′ shown in FIG. 7, which is a primary molded product (intermediate product) including the resin portion 20 having the portion 23 and a secondary molded product (final molded product), is, for example, an electronic control unit. Etc. are used as fastening members.

  As shown in FIGS. 2 to 4, a hexagonal protruding portion 24 is integrally formed on the bottom portion 23 of the resin portion 20. A plurality of notches 22 are formed on the side surface 21 of the resin portion 20 on the upper surface 12 side of the bag-shaped nut 11 at positions facing the apexes 24a of the hexagonal protrusions 24. That is, the positions of the vertices 24a of the hexagonal projecting portion 24 of the resin portion 20 and the positions of the plurality of notches 22 of the side surface portion 21 have the same positional relationship (positions whose angles from the center are in the same phase). Further, the plurality of notches 22 are formed at equal intervals in a V-shaped concave groove shape.

  As shown in FIG. 3, the protruding portion 24 integrally formed on the bottom portion 23 of the resin portion 20 has a hexagonal shape that forms an inscribed circle larger than the diameter of the female screw hole 15 of the bag-shaped nut 11. Is formed.

  Next, a procedure of secondary molding of the insert nut 10 of the embodiment will be described with reference to FIGS.

  First, when the insert nut 10 is secondarily formed, a housing recess 41 having a bottom surface 42 on which the upper surface 12 of the bag-shaped nut 11 is arranged and a positioning portion 43 fitted on each notch 22 on a cylindrical inner peripheral surface. In order to form the lower mold 40 made of metal on the fixed side and the molded resin part 30 integrally molded with the protruding part 24 of the resin part 20, a hermetically closed cavity (with the molding surface 44 of the lower mold 40) is formed. The upper mold 50 made of metal on the movable side having the molding surface 54 forming the closed filling space K is used. The plurality of positioning portions 43 of the lower mold 40 are for positioning the insert nut 10 as a primary molded product, are formed in an inverted V-shaped convex shape at equal intervals, and have a molten resin at the time of insert molding. (Molding material) The position corresponds to the flow direction of R.

  Then, as shown in FIG. 4, while inserting the notches 22 of the resin portion 20 of the insert nut 10 into the respective positioning portions 43 of the lower mold 40, the upper surface 12 of the bag-shaped nut 11 of the insert nut 10 is lowered. The hexagonal protrusion 24 of the resin portion 20 is located in the cavity K at the bottom surface 42 of the recess 41 of the mold 40 (setting step).

  Next, as shown in FIG. 5, the molding resin part 30 is injection-molded so as to cover the protruding part 24 of the resin part 20 by filling the closed cavity K with the molten resin R (molding step).

  Next, after the molten resin R is solidified (hardened), as shown in FIG. 6, the movable upper mold 50 is released from the fixed lower mold 40 and subjected to secondary molding (final molding). Take out the inserted nut 10 '.

  As described above, the position regulation and the holding of the insert nut 10 which is the secondary insert part in the accommodation recess 41 of the lower mold 40 on the fixed side are performed by the side portions 21 of the resin portion 20 which is the resin portion of the insert nut 10. Since the positioning is performed at the notch 22 and the positioning portion 43 of the accommodation concave portion 41 of the lower mold 40, damage to the screw portion of the female screw hole 15 of the lower mold 40 and the bag-shaped nut 11 can be suppressed.

  As shown in FIG. 5, when the insert nut 10 is inserted and set in the housing recess 41 of the lower mold 40, a resin portion is formed on the cylindrical inner peripheral surface 41 a of the housing recess 41 of the lower mold 40. Since the outer peripheral surface 21 a of the side surface portion 21 of the 20 is slidably contacted and regulated, the insert nut 10 can be set in the receiving recess 41 of the lower mold 40 without tilting.

  Further, by forming the protruding portion 24 of the resin portion 20 into a hexagonal shape, it is possible to prevent the resin portion 20 from being turned by a tightening torque when tightening the bolt to a counterpart bolt (not shown).

  Further, when the molding resin portion 30 is injection-molded, the apexes 24a of the protruding portions 24 of the resin portion 20 are oriented parallel to the flow direction of the molten resin R, so that the flow of the molten resin R is received and injected. The influence of the pressure can be suppressed, and the molten resin R can be reliably injected into the closed cavity K in a stable state. Thereby, the insert nut 10 'which is a high quality secondary molded product can be manufactured.

  In addition, according to the above embodiment, the protruding portion of the resin portion is formed in a hexagonal shape, but may be formed in another polygonal shape such as a square shape.

10 Insert nut (primary molded product)
10 'insert nut (secondary molded product: final molded product)
11 Bag-shaped nut 12 Upper surface 13 Outer peripheral surface 14 Lower surface 15 Female screw hole (screw hole)
15a Opening 20 Resin part 21 Side part 22 Notch 23 Bottom part 24 Hexagonal projection (polygonal projection)
24a Apex 30 Molding resin part 40 Lower mold 41 Housing concave part 42 Bottom surface 43 Positioning part 50 Upper mold K cavity (filling space)
R molten resin (molding material)

Claims (4)

A metal nut having an opening for a screw hole on the upper surface side and a bottomed screw hole with a closed lower surface side,
A resin portion having a side portion that covers an outer peripheral surface of the nut and a bottom portion that covers a lower surface of the nut, exposing an opening of a screw hole of the nut,
An insert nut as a primary molded product having
A polygonal protrusion is formed on the bottom surface of the resin portion,
An insert nut, wherein a plurality of cutouts are formed on the upper surface side of the nut on the side surface of the resin portion at positions opposite to the positions of the vertices of the polygonal protrusion. The insert nut according to claim 1, wherein
The plurality of cutouts are formed in a V-shaped concave groove at equal intervals. A metal nut having an opening for a screw hole on the upper surface side and a bottomed screw hole with a closed lower surface side,
A resin portion having a side portion that covers an outer peripheral surface of the nut and a bottom portion that covers a lower surface of the nut, exposing an opening of a screw hole of the nut,
With
A polygonal protrusion is formed on the bottom surface of the resin portion,
A plurality of cutouts are formed on the upper surface side of the nut on the side surface of the resin portion at positions corresponding to the vertices of the polygonal protrusions. The following molding method,
A lower mold including a bottom surface on which the upper surface of the nut is arranged and a housing recess having a positioning portion fitted into each of the notches;
An upper mold that forms a filling space together with the lower mold to form a molded resin part that is integrally formed with the protrusion of the resin part,
While inserting the respective notches into the positioning portion, the upper surface of the nut is arranged on the bottom surface of the housing recess, a setting step of positioning the protrusion of the resin portion in the filling space,
A molding step of molding the molding resin portion so as to cover the projecting portion of the resin portion by filling the filling space with a molten resin,
A secondary molding method for an insert nut, comprising: A secondary molding method for an insert nut according to claim 3,
The plurality of notches are formed at regular intervals in a V-shaped concave groove shape,
The positioning method according to claim 2, wherein the positioning portion is formed in an inverted V-shape and formed at equal intervals.

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