JP3082513B2 - Resin parts - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin part whose internal thread is cut by a tapping screw.

[0002]

2. Description of the Related Art Conventionally, as this kind, there is, for example, one shown in FIG. In the figure, reference numeral 1 denotes a resin boss formed on a resin component. The resin boss 1 is formed with a tapping screw cutout hole 2 in which a female screw is cut by a tapping screw 4. A tapered surface 5 having an angle substantially equal to the angle of the tip 4a of the tapping screw 4 is formed.

In order to perform tapping, the tip 4a of the tapping screw 4 is inserted into the tapping screw cutout hole 2. At this time, the tapered surface 5 guides the tip 4a of the tapping screw 4, Insertion becomes easy. After that, the tapping screw 4 is rotated and screwed into the tapping screw cutout hole 2, and the female screw is screwed together while being cut inside the tapping screw cutout hole 2 to join the members together.

[0004]

However, in such a conventional device, the tapered surface 5 has only a function of simply guiding, and has a function of aligning the axis of the tapping screw 4 with the axis of the tapping screw cutout hole 2. 4, the axis of the tapping screw 4 may be inclined as shown by the angle θ in FIG. 4, and if the tapping is performed as it is, the female screw may not be cut well.

When the tapping screw 4 is attached or detached in such a manner, the position at which the resin boss 1 is cut out by the blade 6 of the tip end portion 4a of the tapping screw 4 varies, so that the tapping screw is temporarily removed. If the tapping screw 4 is removed and the tapping screw 4 is screwed into the resin boss 1 again, the resin boss 1 is cut out from a different portion, and the previous female screw portion is crushed, and the bonding strength is reduced.

As described in, for example, Japanese Patent Publication No. 44-31890, a spiral screw engaging edge is formed by using a spring plate material. This is not the same as the above-mentioned resin component, and also in this case, it cannot be reliably guided, and is easily screwed obliquely.

Accordingly, the present invention provides a resin component having a function of aligning the axis of the tapping screw with the axis of the tapping screw cutout hole when tapping, and which does not have a possibility of reducing the fastening force when screwing in again. That is the task.

[0008]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above problems, and is provided with a female screw in a tapping screw cutout hole by being tapped by a tapping screw having a helically formed blade. Is formed at the opening of the tapping screw cut-out hole, a seating surface is formed in contact with the top of the blade at the tip of the tapping screw, and the seating surface is at least one round of the tapping screw. The top of the minute blade is set to be in contact, and at the end position on the back side of the tapping screw cutout hole of the seating surface, the seating surface has a cutout surface that has a certain angle with the seating surface and serves as a cut surface during tapping. It is characterized by resin parts.

[0009]

According to this means, when the tip of the tapping screw is brought into contact with the opening of the tapping screw cutout hole to perform the tapping of the resin component, the tapping screw is formed on the seating surface formed at this opening. The top of the blade at the tip comes into contact over the area of one round of the screw. Therefore, since the tapping screw is guided over the entire circumference and at least within the range of the length of one lead, the axis of the tapping screw coincides with the axis of the tapping screw cutout hole.

From this state, when the tapping screw is rotated and screwed into the tapping screw cutout hole, the blade at the tip of the tapping screw cuts the female screw from the cutout surface formed at the end position of the seating surface.

As described above, since the tapping screw is guided by the seat surface and the tapping screw can be always kept in alignment with the axis of the tapping screw and the axis of the tapping screw cutout hole, the tapping screw can be screwed in again. Since the cutting is performed from the same position, there is no possibility that the previous female screw portion is crushed and the bonding strength is reduced as in the related art.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 to 3 show one embodiment of the present invention. The same or equivalent members as those in the related art will be described with the same reference numerals.

First, the structure will be described. In the figure, reference numeral 7 denotes a resin boss formed on a resin part, and the resin boss 7 has a tapping screw 4 having a blade 6 formed in a spiral shape.
However, a tapping screw cutout hole 8 to be screwed and connected is formed.

A seating surface 10 for guiding the tip 4a of the tapping screw 4 is formed in the opening 9 of the tapping screw cutout hole 8.

The seating surface 10 is formed over 360 °, and is set so that the top portion 6a of the blade 6 at the tip end portion 4a contacts over the length of one round of the tapping screw 4. I have. As shown in FIG. 2, the inclination angle of the seat surface 10 is gradually changed, and the inclination angle α of the initial position x is changed.
1, the inclination angle α2 of the terminal position Y is smaller. As a result, a step portion is formed in this portion, and the surface of the step portion is the cutout surface 11. This cut surface 1
1 is formed at a certain angle with the seating surface 10.

Next, the operation will be described.

When the tip 4a of the tapping screw 4 is applied to the opening 9 of the tapping screw cutout 8 to perform the tapping of the resin boss 7, the tapping screw is formed on the seating surface 10 formed in the opening 9. Tip 4
The top portion 6a of the blade 6a contacts over a range of one round of the screw. Therefore, since the tapping screw 4 is guided over the entire circumference and at least within the range of one lead length, the axis of the tapping screw 4 coincides with the axis of the tapping screw cutout hole 8.

In this state, when the tapping screw 4 is rotated and screwed into the tapping screw cutout hole 8, the blade of the tip 4 a of the tapping screw 4 is turned into a female screw from the cutout surface 11 formed at the end position Y of the seating surface. It is cut out.

As described above, the tapping screw 4 is guided by the seating surface 10 so that the tapping screw 4 is always
Since tapping can be performed in a state where the axis of the tapping screw is aligned with the axis of the tapping screw cutout hole 8, even if the tapping screw 4 is screwed in again, cutting is performed from the same position. There is no possibility that the portion is crushed and the bonding strength is reduced.

In this embodiment, the resin boss 7 has been described as a resin part. However, the present invention is not limited to this, and any resin having a tapping screw cutout opening, such as a resin housing, may be used. Naturally, components may be used.

[0022]

As described above, according to the present invention, the tapping screw is always screwed along the tapping screw cutout hole with the axis of the tapping screw being aligned with the axis of the tapping screw cutout hole. In addition, it is possible to provide a resin component that does not damage the tapping screw cutout hole when screwing in again and does not have a possibility of reducing the fastening force.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a resin boss according to one embodiment of the present invention.

FIG. 2 is a cross-sectional view of the resin boss of the same embodiment, taken along line AA of FIG. 1;

FIG. 3 is a perspective view showing a resin boss of the same embodiment and enlarging a main part.

FIG. 4 is a sectional view showing a conventional resin boss and corresponding to FIG. 2;

[Explanation of symbols]

 7 Resin boss 8 Tapping screw cutout hole 9 Opening 10 Seat surface 11 Cutout surface Y end position

Claims (1)

(57) [Claims] 1. A resin component in which a female screw is cut into a tapping screw cutout hole by being tapped by a tapping screw having a helically formed blade, wherein the tapping screw cutout hole has an opening. A seating surface is formed to be in contact with the top of the blade at the tip of the tapping screw. The seating surface is set so that the top of the blade at least for one round of the tapping screw is in contact with the tapping screw. A resin component having a cut surface at a terminal position on the back side of the screw cut hole, which has a fixed angle with the seat surface and serves as a cut surface at the time of tapping.