JP2013253627A - Insert nut and resin molded product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an insert nut configured to fasten a plurality of bus bars with bolts in a simple and inexpensive structure even when various voltages are used or a resin molded product is made compact, in order to solve the following problem: when the resin molded product requires various voltages to be used or further reduction in height of the resin molded product, costs and product area are increased, while additionally digging a metal housing or increasing the area of insulation paper for insulation, and to provide a resin molded product including the insert nut.SOLUTION: An insert nut includes a nut body having a screw part for screwing a bolt, and a flange arranged in an outer periphery of an end of the but body and having an end surface arranged on the same surface as an opening end surface of the screw part. An annular step part for stopping the nut body is provided in the end surface of the flange. A serrated or a polygonal nut body baffle part is formed in a raised part (an outer circumferential surface of the flange) of the annular step part.

Description

  The present invention relates to a metal insert nut used by being inserted into a resin product, and a resin molded product including the insert nut.

  In the conventional resin molded product, as shown in FIGS. 7 to 9, when a plurality of bus bars 40 are fastened to the resin molded product 10 with bolts 50, metal chips 56 generated in the nut 20 when the bolts 50 are fastened. In addition, as a measure for securing the space insulation distance L1 between the metal housing 30 and the tip of the bolt 50 or the creeping insulation distance L2 between the nut 20 and the metal housing 30, insulating paper is attached to the resin molded product 10 or the metal housing 30. The insulation distance is secured by pasting 70.

JP 2002-161910 A

In the case of conventional resin molded products, if it is necessary to diversify the operating voltage or further reduce the height of the resin molded products, insulation measures can be taken by adding a metal housing or expanding the area of the insulating paper. There are problems such as increased costs and increased product area.
The present invention has been made to solve the above-described problems, and a plurality of bus bars can be bolted with a simple and inexpensive structure even for diversified operating voltages and downsizing of resin molded products. It is another object of the present invention to provide an insert nut and a resin molded product provided with the insert nut.

  An insert nut according to the present invention is provided on a nut body having a threaded portion for screwing a bolt and an outer periphery of an end portion of the nut body, and an end surface is disposed on the same surface as an end surface of the opening of the threaded portion. Provided with an annular step portion for preventing the nut body from being removed from the end surface portion of the flange, and a serrated or polygonal nut body around the upper portion of the annular step portion (the outer peripheral surface portion of the flange). A stop is provided.

  According to the insert nut of the present invention, the characteristic configuration of the insert nut and the insert nut holding configuration at the time of resin molding can sufficiently receive torque and axial thrust acting on the insert nut in the resin molded product, and resin Since the insulation performance of the molded product can be greatly improved and miniaturized, it is possible to flexibly cope with diversified power conversion devices and the like.

It is an expansion | deployment perspective view of the resin molded product which embed | buried the insert nut. (A) is a top view which shows the insert nut in Embodiment 1 of this invention, (b) is a top view which shows the modification of an insert nut. It is sectional drawing which looked at the AA line in FIG. 2 in the arrow direction. (A) is sectional drawing which shows the state at the time of resin molding of the resin molded product which embeds the insert nut in Embodiment 1 of this invention, (b) is CC line in FIG. 4 (a) in the arrow direction. FIG. It is explanatory drawing which shows the creeping insulation distance of the insert nut in Embodiment 1 of this invention. It is sectional drawing which shows the state at the time of resin molding of the resin molded product which embeds the insert nut in Embodiment 2 of this invention. It is a top view which shows the conventional resin molded product. It is sectional drawing which looked at the BB line in FIG. 7 in the arrow direction. It is the elements on larger scale of the C section in FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In addition, the same code | symbol shows the same or an equivalent part between each figure.

Embodiment 1
FIG. 1 is a developed perspective view of a resin molded product in which an insert nut according to Embodiment 1 of the present invention is embedded.
In FIG. 1, 1 is a resin molded product, and is applied as a terminal block for connecting a plurality of bus bars 4 in a power converter, for example. An appropriate number of insert nuts 2 are inserted into the resin molded product 1 fixed to the metal housing 3, and a plurality of bus bars 4 are fastened by the insert nuts 2 and bolts 5.

Next, the structure of the insert nut 2 is demonstrated based on FIG.
The insert nut 2 has a threaded portion 6b at the center of a cylindrical nut main body 6a, and a nut body lid 8 that closes the threaded portion 6b is provided at an end corresponding to the bottom of the nut main body 6a (the bottom of the threaded portion 6b). A flange 9 is integrally formed on the outer periphery of the other end, which is an opening of the screw portion 6b, and a bag-like nut body (hereinafter referred to as "cap nut body 6") is formed by these members. ing.
The flange 9 is disposed such that the end surface on the screw portion opening side is located on the same surface as the end surface of the cap nut opening of the cap nut body 6, and an annular step portion 9 a for retaining is provided outside the end surface. At the same time, a serrated (not shown) or polygonal nut body detent 9b is provided on the upper part (the outer peripheral surface of the flange).
Further, the nut body cover 8 that closes the screw portion 6b has a structure in which the outer side is covered with a resin material during resin molding and is not exposed to the outside, as will be described later.

  In FIG. 3, the nut body cover 8 and the flange 9 are formed integrally with the nut body 6a. However, when it is difficult to integrally form the insert nut 2, either the nut body cover 8 or the flange 9 is used. Alternatively, both may be formed separately from the nut body 6a and fixed to the nut body 6a by either caulking or welding.

  The nut body detent 9b is replaced with the polygonal one shown in FIG. 2 (a), and a pilot hole (9c) is provided in the flange 9 as shown in FIG. 2 (b), and the cap nut body 6 is inserted into the pilot hole 9c. It is also possible to implement by providing a detent function. According to the adoption of this pilot hole 9c, when the flange 9 has a flat portion 9d and the cap nut body 6 has shape directionality as shown in FIG. The flat portion 9d functions as a nut body detent portion.

Next, the insertion of the cap nut body 6 into the resin material by the resin molding die, that is, the molding of the resin molded product 1 will be described with reference to FIG.
In FIG. 4, for example, a plurality of cap nut bodies 6 are arranged at predetermined positions of a fixed side resin molding die (referred to as a first die) 102. At this time, it arrange | positions so that the end surface of the flange 9 and the thread part opening end surface of the cap nut body 6 may contact | abut to the fixed side resin molding die (1st metal mold | die) 102. FIG. After completion of the arrangement, the end surface of the flange 9 on the side opposite to the screw portion is pressed by the plurality of legs 101a of the movable side resin molding die (second die) 101. That is, the cap nut body 6 is held by sandwiching both end surfaces of the flange 9 opening side end surface and the screw portion non-opening side end surface.

Then, the resin is molded while the flange 9 is sandwiched. When the flange 9 is sandwiched, a separation distance is set between the movable side resin molding die (second die) 101 and the nut body lid 8 (the leg portion 101a is made longer than the body length of the cap nut body 6). ) And the space is filled with resin, so that the nut lid 8 is covered with resin and is not exposed.
Therefore, as in the prior art, resin molding can be performed while the insert nut 2 is securely held without exposing the nut body cover 8 of the insert nut 2. The resin molding die can form a resin molded product even if the fixed side and the movable side are opposite to those in FIG.

The effects expected from the first embodiment are as follows.
In the resin molded product in which the insert nut 2 is inserted, the bolt fastening torque is generated by the serrations formed on the flange peripheral portion of the cap nut body 6, the polygonal peripheral surface portion of the triangle or more, and the pilot hole 9c. The periphery of the nut body 6 is stopped and the idling of the insert nut 2 is prevented. Moreover, the axial thrust of the bolt fastening is handled by the flange 9 of the cap nut body 6 and the annular step portion (for nut body retaining) 9 a formed on the flange 9, thereby preventing the insert nut 2 from falling off. By these functions, peeling between the insert nut 2 and the resin molded product 1 is prevented, and the bolt 5 of the bus bar 4 is securely fastened.
Further, by covering the bottom of the nut body 6a with the nut body cover 8 and forming a bag nut shape, it is possible to prevent metal chips generated when the plurality of bus bars 4 are fastened with the bolts 5 from being scattered outside the insert nut.

At the time of resin molding, the insert nut is set on the fixed side of the mold for resin molding, the end surface on the opening side of the flange portion of the flange 9 is set on the fixed side mold, and the end surface on the non-opening side of the threaded portion of the flange is moved. Since the flange 9 (cap nut body 6) is clamped and held in contact with the mold, if both molds are removed after resin molding, a cavity 101b (FIG. 5) is formed, and the threaded portion opening side end surface of the flange 9 Both surfaces of the threaded portion opposite to the opening side end surface are exposed portions.
For this reason, the space insulation distance and the creeping insulation distance between the exposed portion of the insert nut 2 and the metal housing 3 are significantly increased as compared with the conventional resin molded product, as is apparent from the comparison between FIGS. Therefore, the operating voltage can be increased and the resin molded product can be downsized. Further, as described above, the nut body cover 8 can be prevented from being exposed from the resin.
By these, the insulation performance between the resin molded product 1 in which the insert nut 2 is inserted and the metal housing 3 can be greatly improved. Further, the surface pressure when the bus bar 4 is fastened by the bolt 5 is dispersed by the flange 9 added to the nut body 6a, and the contact resistance between the bus bars 4 can be reduced.

Embodiment 2. FIG.
FIG. 6 is a cross-sectional view showing a state at the time of resin molding of a resin molded product in which an insert nut according to Embodiment 2 of the present invention is embedded.
In the second embodiment, as shown in FIG. 6, the cap nut body 6 is set in a fixed mold, and a gate G (resin inlet) is provided near the nut of the movable mold. At the time of resin molding, the end surface on the opening side of the threaded portion of the flange 9 is held by being pressed against the fixed mold by a molding resin pressure P acting in the direction of the arrow to perform resin molding.
According to this mold, the portion other than the opening surface side of the insert nut 2 is completely covered with resin, and the exposed portion of the insert nut 2 after resin molding is only the surface on the opening side of the flange 9.
In the first embodiment, there is a creeping insulation distance as shown in FIG. 5, but in this second embodiment, there is no such creeping insulation distance, and the space insulation between the exposed portion of the insert nut 2 and the metal housing 3 is not present. Since there is no need to consider the distance and the creeping insulation distance, a greater insulation effect can be obtained than the resin molded product of the first embodiment.

Embodiment 3 FIG.
In the third embodiment, resin molding is performed by press-fitting a cap nut body 6 into a resin molding material. In this press-fitting, a concave portion (corresponding to 2a in FIG. 1) having the same shape as the cap nut body 6 is formed in a resin molded product in advance, and the cap nut body 6 is press-fitted there.
According to the third embodiment, depending on the shape of the resin molded product, when the mold of the first or second embodiment is difficult to use, or when no nut removal load is required, the insert nut is not inserted and the resin is inserted. It can be added to a molded product, and the same effect as in the first and second embodiments can be obtained.

  In the present invention, each embodiment can be appropriately modified or omitted within the scope of the invention.

DESCRIPTION OF SYMBOLS 1 Resin molded product 2 Insert nut 2a Concave shape part of the same shape as the cap nut body 6 3 Metal housing 4 Bus bar 5 Bolt 6 Cap nut body 6a Nut main body 6b Screw part 8 Nut body cover 9 Flange 9a Annular step part (nut body) (For retaining)
9b Nut body non-rotating part 9c Pilot hole 9d Flat part (Nut body non-rotating part)
101 Resin mold (movable side)
101a Leg 101b Void 102 Resin Mold (Fixed Side)
L1 Spatial insulation distance L2 Creepage insulation distance.

Claims (7)

A nut body having a threaded portion for screwing a bolt, and a flange provided on the outer periphery of the end of the nut body, the end surface being disposed on the same surface as the end surface of the opening of the threaded portion;
An insert characterized in that an annular step portion for preventing the nut body from being removed is provided on the end surface portion of the flange, and a serrated or polygonal nut body detent portion is provided on the top of the annular step portion. nut.   The bottom of the threaded portion of the nut body was covered with a nut body lid, and either or both of the nut body lid and the flange were formed separately or integrally with the nut body to form a cap nut body. The insert nut according to claim 1.   The insert nut according to claim 1 or 2, wherein the nut body detent portion is formed by a pilot hole.   A resin molded product formed by embedding the insert nut according to any one of claims 1 to 3 in a resin portion.   The insert nut is set in the first mold on the fixed side or the movable side, and the end face on the screw part opening side and the thread part of the flange between the first mold and the second mold on the movable side or the fixed side. The resin molded product according to claim 4, wherein the resin molded product is formed by holding the insert nut while sandwiching both end surfaces of the end surface on the side opposite to the opening.   The insert at the time of resin molding is set by setting the insert nut on the fixed side or movable side mold and pressing the end surface on the screw part opening side of the flange against the fixed side or movable side mold by molding resin pressure. The resin molded product according to claim 4, wherein the resin molded product is formed by holding a nut.   The resin-molded product according to claim 4, wherein the insert nut is press-fitted into the resin portion.

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