KR101143335B1 - Insert nut having a structure of slanting grid - Google Patents

Abstract

PURPOSE: A slash lattice structure type insert nut is provided to enhance the strength of a pull-out force of an insert nut by multiplying the number of protrusions because an angle between slashes is maintained at 36 to 39 degree. CONSTITUTION: A slash lattice structure type insert nut comprises a flange(301), a body(303), and a fastening protrusion(311). The fastening protrusion is formed on the outer circumference of a forging mold by a rolling-process. The fastening protrusion is formed into a slash form having a predetermined angle. A rolled molding groove caused by a gap between the fastening protrusions is maintained at 0.6mm to 1.4mm. A horizontal fastening protrusion(313) having a horizontal structure in the lower part of the body where the fastening protrusion is formed is rolling-molded.

Description

INSERT NUT HAVING A STRUCTURE OF SLANTING GRID}

The present invention relates to an insert nut, and more particularly, to form an oblique binding protrusion so that the molten portion of the base material can be seated on the upper portion of the binding protrusion during insertion of the insert nut, and the molten portion of the base material is between the binding protrusions. The present invention relates to an oblique grating structure insert nut that can increase the binding force between the base material and the insert nut by setting the angle, interval, and depth of the diagonal line so that a sufficient amount can be fused.

In general, screw fastening members are widely used in assembling two members into one unit. In recent years, an insert nut that is injection molded integrally with a product is used in a product requiring thinning, such as an electronic product. For example, a mobile phone cover or a main body is mostly molded and assembled into a case divided into two, and an insert nut is provided by press-injection or insert injection to facilitate assembly of electronic components in such a case.

The insert nut is fixedly mounted to a mechanism made of a material such as a resin material having a hole of a certain size to improve the cumbersome process of forming a threaded hole in the body or a part of the housing to join any device It is a kind of coupling mechanism for fastening screws or bolts having a range of diameters.

The insert nut is injected and inserted into the hole of the housing fixed by the jig and fixed integrally. At this time, the insert nut is fastened by the crimping tool in a manner of instantaneous heat fusion using the high frequency current. The instantaneous thermal fusion is different in temperature depending on the type of the base material into which the insert nut is inserted. Usually, the insert nut is heated to a temperature of 300 ° C. or higher, and then press-installed in the insertion hole of the base material.

Therefore, the inner circumferential surface of the insertion hole of the base material is melted by the insert nut temperature, and is fused between a plurality of protrusions formed on the outer circumference of the insert nut in the melting process, thereby forming a coupling between the base material and the insert nut.

Then, look at the conventional insert nut as follows.

1 is a view for explaining a conventional insert nut, as shown in the accompanying patent document, the insert nut 2 is tabbed on the inner circumferential surface 4 and a plurality of longitudinal grooves 6 are densely formed on the outer circumferential surface 6. ) And a cylindrical insert portion 12 in which a plurality of binding protrusions 10 protrude in a lattice form by means of a horizontal groove 8 and a flange portion 14 integrally attached to one end of the insert portion 12. It includes. Each corner is chamfered. In particular, the tip of the insert portion 12 inserted into the base material is rounded to facilitate insertion into the base material.

The binding protrusion 10 is made by the longitudinal groove 6 which is recessed in the direction perpendicular to the longitudinal direction of the insert part 12 and the longitudinal groove 6 which is recessed along the longitudinal direction of the insert part 12. The insert part 12 may be inserted into or separated from the base material through a spiral movement such as a screw or a bolt. The horizontal groove 8 can be left-handed or right-handed as needed. Furthermore, the horizontal groove 8 may take the form of two or three rows of screws, including one row of screws.

The flange portion 14 has a circular outer surface and inner surface, but may be made of a hexagonal or polygonal groove on the inner surface or the outer surface of the hexagonal or polygonal shape so as to rotate through a spanner or wrench.

Since the depth of the vertical grooves 6 to the horizontal grooves 8 or the angle of depression are determined according to the conventional insert nut, detailed shapes and dimensions will not be described. If the depth of the grooves 6 and 8 is large, the force embedded in the base material M will be strong, and if the depth of the grooves is shallow, vice versa.

In addition, the insert nut 2 is composed of a cylindrical insert portion 12 and a flange portion 14 integrally attached to one end of the insert portion. First, the prepared round bar is cut into unit lengths, and a cutting step for making the unit round bar is performed. The length of the unit round bar will be arbitrarily determined within the range in which press working is possible. A punching step is followed by forming the cut unit round bar using a press punch to form an outer basic shape and an inner circumferential surface.

In this punching step, a complete bolt hole may be drilled into the unit round bar or chamfered at each corner. The bolt hole for forming the inner circumferential surface 4 of the insert portion may be completely penetrated by two or more detailed punching steps or may be perforated by one punching. Therefore, the insert nut and mass production which are easy to insert and install in a base material are attained.

However, the above-described conventional insert nut varies the coupling force between the base material and the insert nut according to the depth of the groove between the grid, the depth of the groove is determined by the method of processing the transverse groove. Here, there is a difficulty in arbitrarily adjusting the depth of the grooves even if the horizontal axis grooves are processed by forging or the cutting is performed by a roll die.

That is, the horizontal groove formed perpendicular to the serration forms a plurality of rectangular grids on the outer circumferential surface of the insert nut, and the angle between the grids of the insert nuts is 60 °. Therefore, when the insert nut is ultrasonically heated and pressed into the base material, the molten base material is not sufficiently seated at the upper end of each lattice of the insert nut. This causes a problem that the pull-out force of the insert nut is lowered as the base metal melted between the lattice and the lattice flows down by the lattice angle, and then sticks.

That is, when the angle between the grids is reduced, not only the rolling die for forming the transverse grooves can be accurately formed, but also the mold is broken during the rolling process, and thus it is difficult to substantially reduce the angle between the grids. . In addition, even when the serration and lattice are formed in the forging process, it is very difficult to form the angle between the lattice 60 ° or less in order to maintain the precision and durability of the forging die.

Applicant tested the pull-out force of the insert nut having a conventional rectangular grid shape, the base material of the injection molding material PA66-GF35, PA6-GF30 which is commonly used, as shown in FIG.

As shown, the unit of pullout force is kgf, and the ultrasonic heating temperature of the insert nut was maintained at 300 ° C to 350 ° C. As will be appreciated, the average is 634 kgf when a base material of PA66-GF35 is used, and an average of 628.1 kgf when a PA6-GF30 base material is used. As a result of the experiment, the pull-out force of the insert nut with a square lattice falls within the domestic specification range, but has a problem that falls short of the specification for overseas export (specific buyer demand).

1. Republic of Korea Patent Application Publication No. 10-2009-0057498, titled 'Insert nut and its manufacturing method'

The present invention has been made to solve the above problems, and an object of the present invention is to process the binding protrusion of the insert nut in a diagonal form, the melted portion of the base material is sufficiently fused between the diagonal protrusion binding protrusion pull-out of the insert nut An object of the present invention is to provide a diagonal grating structure insert nut capable of improving the force.

Another object of the present invention is to improve the pull-out force of the insert nut, in order to minimize the machining load during the rolling process, by maintaining the angle between the diagonal line 36 ° to 39 °, compared to the binding protrusion of the horizontal structure By increasing the number of protrusions to increase the pull-out force strength of the insert nut, while minimizing the processing load during the rolling process, it provides a diagonal grid-structured insert nut to maintain product productivity.

Diagonal lattice structure insert nut according to an aspect of the present invention for achieving the above object, the insert nut formed on the outer circumferential surface of the body by a forging process on the outer circumferential surface of the forging die formed by forging the flange and the body to an insert nut In this case, the binding projection is formed in an oblique shape having an angle A, the roll forming grooves by the interval between the binding projections is characterized in that to maintain 0.6mm to 1.4mm.

In the diagonal grating structure insert nut according to the preferred embodiment of the present invention, the forging die formed by forging a flange and a body is pressed by a forging process between a forging die block provided with a forging die protrusion, and then rotating the forging die by forging the forging die. In the insert nut in which the binding projection is formed on the outer circumferential surface of the mold, the rolling die projection of the rolling die block maintains a width of 1mm, the spacing between the rolling die projections is 0.7mm, while the rolling die projection is a rolling die block It characterized in that it is processed in the form of oblique inclination by A ° from the vertical angle to the longitudinal direction of the.

On the other hand, the angle A according to an embodiment of the present invention maintains 36 ° to 39 °, characterized in that fore-molding a horizontal type binding protrusion having a horizontal structure on the lower end of the body formed with the binding protrusion.

The diagonal grating structure insert nut proposed in the present invention maintains the angle between the diagonal lines at 36 ° to 39 °, thereby increasing the number of protrusions compared to the horizontally bound protrusion, thereby increasing the pull-out force strength of the insert nut. Minimizing the processing load during the rolling process has the effect of maintaining the productivity of the product. In addition, as the present invention processes the binding protrusions in an oblique form, the molten portion of the base material is sufficiently fused between the oblique binding protrusions to have an effect of improving the pull-out force of the insert nut.

1 is a view for explaining an insert nut having a conventional rectangular grid form.
2 is an experimental result showing the pull-out force strength of the conventional insert nut.
3 is a perspective view showing an insert nut structure having a diagonal grid shape according to the present invention.
4 is a view for explaining the roll forming for the manufacture of FIG.
FIG. 5 is a view for explaining a relationship between the rolling die of FIG. 4 and a binding protrusion corresponding thereto. FIG.
6 is a view for explaining the angle of the diagonal structure according to the present invention.
Figure 7 is a chart showing the measurement for the pullout force strength of the insert nut according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

3 is a perspective view showing an oblique grating structure insert nut according to the present invention. As shown, after the flange 301, the body 303, the threaded portion 305 is formed through the forging process, the diagonal binding protrusion 311 of the diagonal structure through the forging process, and the diagonal binding protrusion 311 A horizontal binding protrusion 313 having a horizontal structure is formed in the lower portion of the).

The forging process cuts the metal rod to a predetermined size, and then integrally processes the body 303 introduced into the base material and the flange 301 coupled to the upper side of the base material. Then, the shape of the insert nut is completed by drilling the threaded portion 305. Thereafter, an oblique binding protrusion 311 is formed through a rolling process, and a horizontal binding protrusion 313 formed horizontally under the oblique binding protrusion 311 is processed as necessary.

As such, the diagonal binding protrusion 311 is inserted into the base material after the insert nut is heated by ultrasonic heating, and in this process, the insert opening of the base material is melted, and the molten portion of the base material is the diagonal binding protrusion 311. It is pulled in and fused in between. Therefore, the binding force between the base material and the insert nut is increased only when the capacity of the base material melt portion to be fused is high.

The diagonal lattice structure proposed in the present invention increases the binding force between the base material and the insert nut by widening the contact surface between the molten portion and the binding protrusion of the base material, and widening the contact surface can be assumed to increase the number of the binding protrusions 311. have. For example, the above-described diagonal binding protrusion 311 is manufactured by a rolling process, and the binding protrusion is formed by a rolling die protrusion in the rolling process.

That is, as illustrated in FIG. 4, the rolling process includes a flange 301 and a body between two rolling die blocks 401 and 401 ′ provided with a rolling die protrusion 403 for forming a diagonal binding protrusion 311. After the forging die 405 having the 303 formed therein is introduced, the forging die blocks are pressed together with each other, and the forging die 405 is rotated to roll the diagonal binding projection 311.

In this process, as shown in Figure 5, the protruding die projection 403 is composed of a width of 1mm, the spacing between the protruding die projections 403 is composed of 0.7mm, the minimum interval for processing the mold block. . Here, it may be desirable to maintain a minimum value between the gap between the forging dies 403, and the width of the forging dies 403 may be advantageous as wide as possible to allow the molten portion of the base material to enter, but this is the number of binding protrusions. Since it is a source of reducing the number, it is desirable to design the proper width.

Therefore, while increasing the number of binding projections, the width of the preformed groove 501 is designed to be 0.6mm to 1.4mm in order to maintain the width that the molten portion of the base material can be sufficiently fused. Here, when the width is less than 0.6mm, there is a problem in that the molten portion of the base material is not sufficiently drawn in general, and when the width is more than 1.4mm, the number of diagonal binding protrusions 311 is reduced, and thus, the binding force between the base material and the insert nut is reduced. It causes the problem of deterioration.

Then, in order to examine the oblique angle of the binding protrusion for increasing the number of diagonal binding protrusions 311, the specification of the insert nut specified first is as follows.

The insert nut has a cylindrical structure of 11 mm in diameter, and the diameter of the flange 301 is 12 mm. Of course, according to the shape or size of the base material, the insert nut may be composed of a diameter of 12.7mm, the diameter of the flange 13.7mm, the type is limited to the above two specifications. However, the above-described body 303 of the two insert nuts, i.e., the parts to be roll formed, have the same height as 5.5 mm, and the roll die projection 403 onto the outer circumferential surface of the body 303 having a height of 5.5 mm. Roll molding is achieved.

According to this specification, when forming the binding projections of the horizontal structure on the outer peripheral surface of the body 303, as shown in Figure 6a, up to three (when the binding projections are processed horizontally, 1mm, the width of the rolling die projections, rolls The number of protrusions formed between a minimum distance of 0.7 mm of the mold protrusions and a width of 5.5 mm of the body 303) is formed, but the binding protrusions are formed in an oblique form inclined at an arbitrary angle A as shown in FIG. 6B. In this case, three or more binding protrusions can be formed. Increasing the number of fastening protrusions can increase the pull-out force strength of vertically withdrawing insert nuts inserted into the substrate.

However, since the angle A of the oblique line for forming the above-mentioned binding protrusion is formed by the rolling die protrusion 403 formed in the rolling die block 401, the forging die protrusion 403 and the forging by the angle A of the oblique line are forged. Consideration should be given to the load between the molds 405. If the forging die 403 is horizontal, that is, the angle A is closer to 90 °, the rotation load of the forging die 405 in the forging process is increased to the maximum, thereby making the machining itself impossible. Substantially, when the angle A is 45 ° or more and less than 90 °, there is a problem in that the rotational load increases and productivity is lowered.

On the other hand, when the angle A is designed to be close to 0 °, as described above, the number of binding protrusions is reduced to a minimum, thereby lowering the pull-out force strength. Then, in setting the angle A, as indicated in FIG. 6B, the sum of the gap between the roll forming groove B formed by the rolling die projection 403 and the rolling die projection 403 must be calculated. For the angle A, the values of B and C are represented by Equation 1 below;

tan (A) × (Minimum working distance between rolling die projections + Width of rolling die projections) = B + C

to be. The minimum processing interval between the forging dies is 0.7 mm, and the width of the forging dies is 1 mm. Thus, the 'B + C' value is;

B + C = tan (A) x 1.7

Here, B should be 0.6mm to 1.4mm as the preformed groove 501, and since the oblique line formed by the angle A should be larger than three horizontal oblique lines, the number of oblique lines should be at least four.

Therefore, considering that the width of the body 303 is 5.5 mm, the condition of "5.5 / (tan (A) x 1.7) = 4 or more" must be satisfied.

Here, when the number of diagonal lines is set to four, tan (A) = 0.80, where the angle A is 39 °. In addition, when setting the number of diagonal lines to five, tan (A) = 0.64, and the angle A is 33 degrees. In the same way, if the number of diagonal lines is to be 6, tan (A) = 0.53, and the angle A is 28 °, and when the number of diagonal lines is 7, tan (A) = 0.46, the angle A Is 25 °. However, the number of diagonal lines may not be increased infinitely, because it affects the thickness of the diagonal binding protrusion 311.

That is, the thickness of the diagonal binding protrusion 311 is formed by the gap between the precursor die projections 0.7mm, the interval of at least 0.5mm should be maintained for durability of the product. Therefore, when the angle A is 39 °, the thickness C of the binding protrusion 311 is 0.56 mm, and when the angle A is 33 °, the thickness C of the binding protrusion 311 is 0.45 mm. Thus, the angle of the oblique line should be less than 39 ° and greater than 36 ° (tan (36) x 0.7 = 0.508). And, the number of diagonal lines formed at this time is limited to four.

As a result, the oblique binding protrusion 311 according to the present invention is formed with an oblique line having 39 ° to 36 ° with respect to the horizontal of the insert nut, thereby pulling out compared to the insert nut having a horizontal binding protrusion, for example, a square lattice. Force strength can be increased. This principle is because the binding force between the base material and the insert nut is increased by increasing the number of binding protrusions that can be formed horizontally.

Meanwhile, as another embodiment of the present invention, a horizontal binding protrusion 313 having a horizontal structure may be formed below the body 303 provided with the diagonal binding protrusion 311. This allows the molten portion of the base material to be fused to the space between the horizontal binding protrusions so that the molten portion of the base material introduced between the diagonal binding protrusions 311 does not flow downward. That is, when the base material melt portion is drawn between the diagonal binding protrusions 311 by the diagonal structure of the diagonal binding protrusion 311, the downward flow flows downward due to the oblique protrusions. This is to allow the molten base material to prevent this.

On the other hand, the present inventors have experimented with the pull-out force of the insert nut having a conventional rectangular grid, the base material of the injection molding material PA66-GF35, PA6-GF30 which is commonly used in the vehicle, the diagonal binding protrusion ( The pullout force for the insert nut 311) is as shown in Figure 7a.

As shown, the unit of pullout force is kgf, and the ultrasonic heating temperature of the insert nut was maintained at 300 ° C to 350 ° C. As can be appreciated, when the base material of PA66-GF35 material is used, the average is 762.9kgf, and the strength is increased by 20.3% compared to the insert nut of the conventional square grid type. In addition, when the PA6-GF30 base material is used, the average is 734.1kgf, it can be seen that 16.8% increase for the same sample.

Figure 7b is the data measuring the pull-out force strength for the insert nut coupled to the diagonal binding projection structure and the horizontal binding projection structure according to the present invention. As shown, when the base material of the PA66-GF35 material is used, the average, 810.2kgf, 6.2% increase compared to the diagonal binding protrusion structure. In addition, when PA6-GF30 substrates were used, the average was 804.9 kgf, an increase of 9.6%.

The insert nut proposed in the present invention has an insert nut that is rolled to maintain the angle between the diagonal lines at 36 ° to 39 °, resulting in an increase in the number of protrusions compared to the binding protrusion of the horizontal structure. Increases the pull-out force strength at the same time, while minimizing the machining load during the rolling process. Therefore, in the present invention, while maintaining the product productivity of the insert nut, it is possible to improve the specification of the insert nut and to target the overseas market therefrom, and thus the industrial use value is high.

301: Frangipani 303: the body
305: thread 311: diagonal binding protrusion
313: horizontal binding protrusion 321: screw thread
401: Rolling die block 403: Rolling die protrusion
405: forging mold

Claims (7)

In the insert nut formed on the outer circumferential surface of the body by a forging step onto the outer circumferential surface of the forging die formed by forging the flange and the body,
The binding projections are formed in an oblique shape having an angle A, and the roll forming grooves by the interval between the binding projections maintain 0.6 mm to 1.4 mm;
Diagonal lattice structure insert nut, characterized in that the roll forming the horizontal binding projection having a horizontal structure on the lower end of the body formed with the binding projection. The method of claim 1,
Diagonal grid structured insert nut, characterized in that the angle A is maintained between 36 ° to 39 °. delete After the forging die formed by forging the flange and the body is pressed by a forging process between the forging die blocks provided with the forging die protrusion, the insert nut is formed by rotating the forging die to form a binding protrusion on the outer circumferential surface of the forging die. To
The rolling die projection of the rolling die block maintains a width of 1mm, the interval between the rolling die projections is kept to 0.7mm, but the rolling die projection is inclined by A ° from the vertical angle with respect to the longitudinal direction of the rolling die block. Processed into;
The rolling die projection of the rolling die block includes a projection for forming the horizontal binding protrusion having a horizontal structure at the bottom of the body in which the binding protrusion is formed. The method of claim 4, wherein
Diagonal grid structured insert nut, characterized in that the angle A is maintained between 36 ° to 39 °. delete delete

Images