JPS633165B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for preventing a set screw of a resin molded product from falling off, and more particularly to a device for preventing a set screw from falling off of a resin molded cap of a power distributor for an automobile.

2. Description of the Related Art Covers of parts installed in the engines of automobiles and the like are often removed for inspection. For example, in the case of engine power distributors,
As disclosed in Publication No. 96138, a resin cap is screwed to the main body of the power distribution device, but this cap is sometimes removed and reattached after inspecting and cleaning the inside. At this time, be careful not to lose the set screw.

FIG. 1 is a front view of a conventional power distributor. A cap 2 made of synthetic resin is fitted onto the upper side of a power distributor body 1 made of die-cast aluminum or the like, and a set screw 3 is screwed into an internal thread provided on the power distributor body 1. A spring washer 5 and a washer 6, which are elastic members, are interposed between the set screw 3 and the cap 2 to tighten them, so the set screw 3 will not fall off even when engine vibrations are applied. .
In addition, a metal bush 4 is buried in the set screw passage hole of the cap 2, and a threaded part is provided on the inside upper part of the bush to enable the set screw 3 to pass through. I'm trying to keep 3 from slipping out.

2 is a front view of the bush of FIG. 1, and FIG. 3 is a vertical sectional view of the bush of FIG. 2. A female threaded portion 41 is formed at one end of the metal bushing 4, which is made of metal and has an annular groove 43 in the middle of the outside and knurls 42 above and below the annular groove 43. This bush 4 is embedded when the cap 2 is molded, but is prevented from rotating by the knurl 42 and from moving up and down by the annular groove 43, so that it is reliably integrated.

FIG. 4 is an enlarged front view of the set screw of FIG. 1. The lower end of the set screw 3 is a commercially available screw having a male thread 31 and a longer neck portion 32. Note that this set screw 3 passes through the female threaded portion 41 shown in FIG. Since the washer 6 is interposed, it will not loosen even if it vibrates.

In conventional power distributors configured in this way, even when the cap 3 is separated from the power distributor body 1, the cap 2 and set screw 3 are not easily separated, so the purpose is to prevent the set screw 3 from falling off. I am satisfied with that.

However, since the commercially available set screw 3 is manufactured by rolling a wire rod having a thickness equal to the effective diameter, which is the middle of the thread diameter and the root diameter, the diameter φd of the lower neck portion 32 is relatively thick. There is. There is a risk that this lower neck portion 32 may come into contact with the threads of the female threaded portion 41 of the bushing 4 and deform it. In order to avoid this, conventionally, the lower neck portion 32 of the set screw 3 was machined to have a smaller diameter, which required time and increased costs. In addition, the bush 4 has a groove 43 and a knurling 42 formed on the outside, and a female threaded portion 4 on the inside.
1 requires a considerable amount of processing time, which also causes high costs.

In addition, in order to use a commercially available set screw 3 as is, it is possible to make the inner diameter of the female thread part 41 larger than the above effective diameter, but due to variations in dimensions during thread cutting, etc., it may fall off completely. This is not practical because it is expected to cause troubles such as difficulty in preventing this or failure to insert the set screw 3.

The object of the present invention is to provide a reliable and inexpensive device for preventing the falling off of resin molded set screws. The resin protrusion is molded so as to protrude into the hole, and the resin protrusion is always in surrounding contact with the lower part of the neck of the set screw.

FIG. 5 is a perspective view of a bush used in a set screw fall prevention device according to an embodiment of the present invention, and FIG. 6 is a sectional view of a main part of a cap in which the bush of FIG. 5 is embedded. In this case, a cross groove 71 is formed on the upper surface of the bush 7, only an annular groove 72 is formed on the side surface without knurling, and no internal thread 41 is provided on the inner surface. That is, the knurling and internal thread cutting processes required when making the conventional bush 4 are omitted, and only a simple milling process for forming the cross groove 71 is required, so the processing time is shortened and manufacturing can be made at low cost. .

This bush 7 has a resin material protruding from the cross groove 71 to form a resin small diameter portion 73 while attaching the cap 2.
Embedded in resin material. Therefore, by rotating and inserting the screw 10 with a guide as shown in FIG. will not fall off. That is, the male threaded portion 31 of the set screw 3 is locked without being able to pass through the female threaded portion 41 of the bush 4.

The device for preventing the set screw from falling off in this embodiment is such that when a tubular bush with a cross groove on the top surface and an annular groove on the side surface is molded into the cap, the resin is made to protrude from the cross groove. , the set screw that has been pushed in while rotating can be locked to the cap without falling off. As a result, it is possible to reliably eliminate the trouble of losing a set screw, and to achieve the effect that the structure can be constructed at a low cost.

FIG. 7 is a perspective view of a bush used in a set screw fall prevention device according to another embodiment of the present invention, and FIG. 8 is a sectional view of a main part of a cap in which the bush of FIG. 7 is embedded. The bush 8 in this case is made by winding a metal plate into a tubular shape with a plurality of holes 81 along one side and a number of recesses 82 on the other side, and 83 is the seam. Since such a bush 8 can be formed entirely by plate-shaped press working, it can be manufactured at low cost. Note that providing the hole 81 close to the upper side of the bush 8 is useful for preventing deformation of the upper end surface of the bush 8 and maintaining its surface accuracy.

If this bushing 8 is embedded and molded in the cap 2, it is possible to obtain exactly the same effect as the bushing 4 shown in FIG. 6. That is, the resin protruding from the hole 81 forms a resin small diameter portion 84 to prevent the set screw 3 from falling off, and together with the numerous recesses 82, ensures the integrity of the bush 8 and the cap 2.

The set screw falling-off prevention device of this embodiment can obtain the same effect as the embodiment shown in FIG. 6 by forming holes and recesses in a metal plate, then winding it into a tubular shape and embedding it in a cap. It also has the advantage that it can be constructed at a lower cost.

FIG. 9 is a plan view of the main part of a cap in which a bush is embedded, which is a modification of FIG. 5. In the case of FIG. 6, the resin small diameter portion 73 is a hole, but in this case, only the cross groove portion is made to protrude and the four resin pieces 9 are inserted.
1 is formed.

FIG. 10 is a sectional view showing a state in which a set screw is inserted into the cap of FIG. 9. A commercially available screw having a guide portion 101 at the tip and a male thread portion 102 is used as the set screw 10, and when inserted while aligning the tips with the centers of the four resin pieces 91, a polypropylene-based elastic resin is inserted. Piece 91 is curved to allow set screw 10 to pass through. This set screw 1
0 is screwed onto the screw of the power distributor body 1 to fix the cap 2 to the power distributor body 1, but even if the setscrew 10 is loosened by rotating in the opposite direction in order to remove the cap 2, the resin piece 91 will not work. The male threaded portion 102 is held in place, and the set screw 10 will not fall off.

The set screw falling-off prevention device of this embodiment has four resin pieces formed by cross grooves provided on the top surface of the bushing, which clamp the lower part of the neck of the set screw and prevent the male thread from passing through. Therefore, it is possible to prevent the set screw from falling off using a simpler method.

The above-mentioned embodiment has been explained by taking as an example the prevention of falling off of a set screw of a cap of an automobile power distribution device. That is,
This has the advantage that the set screw will not fall off and be lost, or fall into the space of a complex structure and cause abnormal noise during operation. It can also be applied to manufactured caps.

The falling-off prevention device for a resin molded product set screw of the present invention has the effect of being able to reliably hold the set screw when a resin cap is removed.

[Brief explanation of the drawing]

Figure 1 is a front view of a conventional power distributor, and Figure 2 is a front view of a conventional power distributor.
3 is a vertical sectional view of the bushing in FIG. 2, FIG. 4 is an enlarged front view of the set screw in FIG. 1, and FIG. 5 is a set screw according to an embodiment of the present invention. FIG. 6 is a sectional view of a main part of a cap in which the bush of FIG. 5 is embedded, and FIG. 7 is a set screw fall prevention device according to another embodiment of the present invention. 8 is a cross-sectional view of the main part of a cap in which the bush shown in FIG. FIG. 10 is a sectional view showing a state in which a set screw is inserted into the cap of FIG. 9. 1...Distributor body, 2...Cap, 7, 8, 9...
Bush, 71...Cross groove, 72...Annular groove, 73,
84...Resin small diameter part, 81...hole, 82...dent, 83
... Seam, 91... Resin piece, 10... Set screw, 1
01...Guide part, 102...Male thread part.

Claims (1)

[Scope of Claims] 1. A main body provided with a female thread, a set screw screwed into the female thread, and a cap that is a resin molded product that is joined to the main body, in which a bushing that is a tubular metal body is embedded. In the device for preventing falling off of a resin molded set screw, the male threaded part of the set screw passes through the bush and is screwed into the female threaded part of the main body, wherein a plurality of notches provided at the upper part of the bush Falling off of a resin-molded set screw, characterized in that a synthetic resin material is molded so as to protrude into the hole of the bush from the removed part, and the resin protrusion is always in surrounding contact with the lower part of the neck of the set screw. Prevention device. 2. A falling-off prevention device for a set screw for a resin molded product as set forth in claim 1, wherein the plurality of cutout portions provided in the upper part of the bushing are a plurality of grooves formed radially on the upper end surface of the bushing. . 3. Preventing the resin molded product set screw from falling off as set forth in claim 1, wherein the plurality of cutout portions provided in the upper part of the bushing are a plurality of holes provided at positions close to the upper end surface of the bushing. Device. 4. Falling off of a set screw for a resin molded product according to claim 1, wherein the bushing is a tubular member made by bending a metal plate formed by pressing the plurality of cutout parts and the plurality of recessed parts. Prevention device.