JP4395560B2 - Fasteners and molded parts - Google Patents

Description

  The present invention relates to a fixing member and a molded product member suitable for use by being fitted and fixed to a molded product member of a synthetic resin used for a housing of a mobile phone or the like, for example.

Conventionally, when a screw hole is formed in a member made of a synthetic resin molded product and a bolt is screwed in and fixed, it receives a tensile, torsional, vibration or other external force, or when it is attached or detached while reversing the bolt etc. Will be deformed or destroyed and become unusable.
Therefore, there is a nut-like metal fixing tool that can be securely fixed by inserting and fixing into a hole provided in a molded product member such as a synthetic resin, and can withstand repetitive attachment and detachment. It has been put into practical use. Furthermore, there has been proposed a method of providing a knurled or other irregularity on the outer peripheral surface of the fixing tool so that such a fixing tool bites into the hole of the molded product member and is fixed with sufficient strength (for example, Patent Documents). 1, 2).

Such a fixing tool is provided with a plug (sometimes referred to as a head, hereinafter referred to as a plug) on the tip side. When the fixing tool is fitted into the molded product member, the fixing tool is guided (guided) by the plug body into the hole of the boss provided in the molded product member, and the fixing tool is fitted by being heated and pressurized. ing.
In recent years, for example, in a case of a mobile phone or the like, there is an increasing demand for a design in which a molded product member is lightened and thinned so as to be described as “light thin and short”. In order to meet such a demand, if the molded product member itself is made thinner and the height of the boss provided on the molded product member is lowered, the boss hole must be made shallower.

  However, there is a problem that the hole of the molded product member designed to be shallow cannot be accommodated in the total length required from the distal end side plug body to the proximal end in the conventional fixing tool.

  Japanese Patent Laid-Open No. 50-85756   JP 58-124809 A

As described above, in order to meet the design demand for making the molded product member lighter and thinner, it is necessary to make the molded product member thinner and further reduce the height of the boss provided on the molded product member. The hole must be shallow. There has been a problem in that it cannot cope with the hole of the molded product member designed to be shallow in the total length required from the distal end side plug body to the proximal end in the conventional fixing tool.
An object of the present invention is to provide a fixing tool and a molded product member that can cope with a shallow hole of a boss in a molded product member that is designed to be light and thin.

Therefore, the present invention provides a fixing tool and a molding product member fixed to a hole provided in a synthetic resin molding product member, wherein the fixing tool has a number of concave and convex strips on the outer peripheral surface of a cylindrical main body. A first large-diameter portion on the proximal end side having an outer diameter smaller than the outer diameter of the first large-diameter portion and a predetermined interval from the first large-diameter portion, A second large-diameter portion on the distal end side that also serves as a plug and has a large number of irregularities on the outer peripheral surface, and the molded product member has an outer diameter of the first large-diameter portion at the top The above-mentioned fixture comprising a first hole diameter which is smaller by a predetermined value and larger than the outer diameter of the second large diameter portion, and a second hole diameter which is smaller by a predetermined value than the outer diameter of the second large diameter portion at the bottom. This is a configuration having a hole to which is fixed.

The fixing tool and molded product member of the present invention can provide a fixing tool and a molded product member that can cope with a shallow hole of a boss in a molded product member that is designed to be light and thin .

1 is a half sectional view showing an example of a fixing tool to which an embodiment of the present invention is applicable. Sectional drawing which shows the shape of a molded article member.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a half sectional view showing a fixing tool 1 called an insert according to the present invention. That is, the fixing tool 1 has a first large-diameter portion 3 on the proximal end side of the short cylindrical main body 2 and a second large-diameter whose outer diameter is smaller than that of the first large-diameter portion 3 on the distal end side of the main body 2. Part 4 is provided. The first large-diameter portion 3 and the second large-diameter portion 4 each have knurls (concave and convex lines). The first large-diameter portion 3 and the second large-diameter portion 4 are formed at a central portion of the main body 2 with a predetermined interval (hereinafter referred to as an interval portion), and the knurling flow direction (shape) Etc.) are provided differently. Furthermore, the end face of the second large diameter portion 4 that is in contact with the front end face b is chamfered to facilitate the operation when the fixing tool 1 is inserted into the hole 12. The shape of the large diameter portion (including the outer diameter, the interval, and the number) can be changed according to the material of the molded product member to be fitted.

The main body 2 is provided with a female screw hole 5 penetrating from the base end surface a of the first large diameter portion 3 to the distal end surface b of the second large diameter portion 4.
The fixing tool 1 of the present embodiment is cut in units of 1/100 mm, and the outer diameters of the first large diameter portion 3 and the second large diameter portion are changed depending on the material of the molded product member.
For example, the dimensions of the fastener 1 are 2.50 mm in total length (end surface a to end surface b), the outer diameter of the first large diameter portion 3 is 2.60 mm, the length is 1.10 mm, and the second outer diameter portion. 4 is cut with an outer diameter of 2.30 mm, a length of 1.10 mm, and an interval between the main body 2 of 0.30 mm.

In addition, although the fixing tool 1 uses brass in the present embodiment, a relatively hard metal such as carbon steel, stainless steel, aluminum, or zinc may be used.
As described above, the fastener 1 of the present invention has a configuration in which the plug provided on the distal end side of the conventional fastener is eliminated.

FIG. 2 is a cross-sectional view showing a configuration example of the molded product member 10 molded of synthetic resin. The molded product member 10 is provided with holes 12 formed in advance in the formed bosses 11. The hole 12 has a bottom portion whose hole diameter is smaller than the outer diameter of the second large diameter portion 4 of the fixing tool 1 by a predetermined value, and whose upper portion is larger than the outer diameter of the second large diameter portion 4 of the fixing tool 1. It is formed in two steps having a hole diameter smaller than 3 by a predetermined value. Moreover, the depth of the hole 12 is formed longer than the full length of the fixing tool. In addition, the depth of the upper part and the bottom part in the hole 12 can be changed according to the material and size of the fixing tool, the material of the molded product member, and the like.
For example, the boss 11 of the molded product member 10 has a total length of 3.50 mm, a hole diameter at the top of the hole 12 of 2.40 mm and a depth of 1.40 mm, a hole diameter at the bottom of the hole 12 of 2.00 mm and a depth of 1. It is molded at 80mm.

In this embodiment, two large-diameter portions of the fixing tool are provided and the hole diameter of the molded product member is two-staged, but a plurality of holes may be used, and the molded product member may be formed according to the outer diameter of the plurality of large-diameter portions. The hole diameter is provided in a plurality of steps. For example, if there are three large-diameter portions of the fixing tool, the hole diameter of the molded product member is three steps, the reference side is the first large-diameter portion, the middle is the third large-diameter portion, and the tip side is the second large-diameter portion. To do.
Moreover, although the fixing tool 1 is provided with the 1st large diameter part 3 and the 2nd large diameter part 4, since the flow direction (shape etc.) of knurls differs, the hole 12 of the molded article member 10 is different. The torsional strength and the tensile strength after being fitted in are greatly improved.

Next, the operation | movement which fits the fixing tool 1 in the hole 12 of the molded article member 10 in such a structure is demonstrated. In other words, in this fitting operation, the fixing tool 1 is pressed while being heated and is fitted into the hole 12 of the molded product member 10.
First, the fixing tool 1 is supplied to the hole 12 of the molded product member by a parts feeder (not shown). At that time, in the upper part of the hole 12 of the molded product member 10, the second large diameter portion 4 of the fixing tool 1 serves as a guide, and the fixing tool 1 is easily inserted. This is because the hole diameter at the top of the hole 12 is larger than the outer diameter of the second large diameter portion 4. That is, when the fixing tool 1 is inserted, the first large-diameter portion 3 larger than the upper hole diameter of the hole 12 is the boss in the state where the second large-diameter portion 4 of the fixing tool 1 is in the hole at the top of the hole 12. It will be in the state which got on the upper surface (the upper part of the boss | hub 11 on the figure).

Subsequently, the fixing tool 1 is heated and pressurized, and the synthetic resin around the hole 12 in contact with the first large-diameter portion 3 and the second large-diameter portion 4 of the fixing tool 1 is softened and melted, so that the first large diameter portion 3 is fixed. The diameter portion 3 and the second large diameter portion 4 are allowed to enter, and the bottom of the hole 12 is reached and stopped. At this time, the peripheral surface resin of the hole 12 in contact with the first large-diameter portion 3 and the second large-diameter portion 4 of the heated fastener 1 is softened and melted to wrap the main body 2 of the fastener 1. Then, the peripheral resin of the softened and melted hole 12 is cooled and cured in a state where the knurled concave portions and the interval portions of the first large diameter portion 3 and the second large diameter portion 4 are filled, and the fixing tool 1 is within the hole 12. Fixed.
That is, in the fixing device 1 of the present embodiment, the peripheral resin at the top of the first large diameter portion 3 and the hole 12 and the peripheral resin at the bottom of the second large diameter portion 4 and the hole 12 are softened and melted. Since each of them is cooled and hardened in a state where the knurled recess and the space are filled, the fixing tool 1 is fixed in the hole 12 more firmly than in the past.

  The heating temperature of the fixing tool 1 varies depending on the outer diameter and shape of the first large diameter portion 3 and the second large diameter portion 4 of the fixing tool 1 and the material of the molded product member 10. For example, the material of the molded product member 10 is 220 ± 10 ° C. when the resin is ABS resin, 270 ± 10 ° C. when the material is polycarbonate, and 260 ± 10 ° C. when the material is ABS resin and polycarbonate.

As described above, according to the embodiment of the present invention, it is possible to provide a fixing tool and a molded product member that can cope with a shallow hole of a boss in a molded product member that is designed to be light and thin.
That is, the total length of the fixing tool can be shortened by eliminating the plug provided on the conventional fixing tool, thereby making it possible to shallow the hole of the molded product member.

Further, the material can be saved by eliminating the plug provided on the conventional fixing tool (useless material is not required).
Also, each of the first large-diameter portion and the second large-diameter portion softens and melts the peripheral resin of the hole, and each of them is cooled and hardened while filling the knurled recess and the interval portion, so that it is fixed to the hole more firmly than before. can do.

  Note that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention in the implementation stage. In addition, the embodiments may be combined as appropriate as possible, and in that case, the combined effect can be obtained. Furthermore, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. For example, even if some constituent requirements are deleted from all the constituent requirements shown in the embodiment, the problem described in the column of the problem to be solved by the invention can be solved, and the effect described in the column of the effect of the invention Can be obtained as an invention.

  DESCRIPTION OF SYMBOLS 1 ... Fastening tool, 2 ... Main body, 3 ... 1st large diameter part, 4 ... 2nd large diameter part, 5 ... Female screw, 10 ... Molded article member, 11 ... Boss, 12 ... Hole.

Claims (1)

A fixing tool and a molded product member fixed in a hole provided in a molded product member of synthetic resin,
The fixing tool includes a first large-diameter portion on the base end side having a large number of irregularities on the outer peripheral surface of the cylindrical main body, and an outer diameter smaller than the outer diameter of the first large-diameter portion. A first large-diameter portion and a second large-diameter portion on the distal end side, which is provided at a predetermined interval and has a large number of irregularities on the outer peripheral surface of the cylindrical main body and also serves as a plug. ,
The molded product member has a first hole diameter which is smaller than the outer diameter of the first large diameter portion by a predetermined value at the top and larger than the outer diameter of the second large diameter portion, and the second large diameter portion at the bottom. A fixing tool and a molded product member having a hole to which the fixing tool composed of a second hole diameter smaller than the outer diameter by a predetermined value is fixed.

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