KR100195162B1 - Spring strip made of plastic composite material - Google Patents

Abstract

A method of adhering plastic composite structures using spring strips is disclosed.

In bonding the upper and lower panels having varying curvature with the lip used as the reinforcement in the prior art, the bonding between the lower panel and the lip first adhered in the adhesive assembly step is easy and stable, but the upper panel and When the space in which the adhesive portion is formed is sealed by the adhesion between the lips, there is a problem that adhesion failure occurs depending on the processing state of the lip.

This problem is made possible by a bonding method using a spring strip as an auxiliary member for bonding, to enable stable and reliable bonding even in a closed space not reachable by human hands.

Such a method can be used in the bonding of various structures fabricated using plastic composites.

Description

Method of bonding spring strip and plastic composite structure using same

The present invention relates to a spring strip for bonding a plastic composite structure and a method for bonding the plastic composite structure using the same.

Today, plastic composites can replace metal and ceramic materials and are expanding their use in the automotive and aircraft sectors. For example, composites made from epoxy base materials and continuous graphite fibers have a tension and robustness comparable to that of steel, although the maximum operating temperature is low. In particular, the weight of the plastic composite in terms of the weight of the material is only about 1/4 of the weight of the metal material with similar properties. Therefore, as the production volume increases in the future and the production cost is lowered, the use area of the plastic composite will be further expanded.

In the prior art, when the plastic composite structures are bonded to each other, not only the difficulty of work is accompanied by the shape or curvature of the bonded structure, but also the reliability of the adhesive may occur. For example, when a rib is formed between the upper panel and the lower panel having a constant curvature to bond both ends of the lip to the panel, the shape of both ends of the lip depends on the curvature of the panel according to the installation position of the lip. Machining precisely to fit involves uneconomical factors. Furthermore, it is not desirable in terms of cost and efficiency to have to individually process both ends of the lip to be bonded when the curvature of the panel and the size of the lip are not uniform depending on the characteristics of the structure, the position used, or the like. However, if the processing precision of the gluing portion of the lip is lowered due to technical reasons, work efficiency, and economic reasons, the adhesion is made nonuniform and the reliability of the adhesion is also lowered.

In addition, even when the bonding end surfaces of both ends of the lip are individually processed, if the processing accuracy of the bonding surface is low, the stability of the bonding site is lowered. In addition, the stability of the adhesive site is worse as the properties of the adhesive used is different from the properties of the base material. Sometimes, even if the properties of the adhesive are superior to the properties of the base material, it can adversely affect the overall stability. For example, when the hardness of the adhesive is high but the adhesive surface is uneven, a stress concentration point that causes cracking may be formed.

(A) of FIG. 1 is a front sectional view of a composite structure bonded according to a conventional method, and FIG. 1 (b) is a front sectional view of a composite structure bonded according to another conventional method.

The method used in (a) of FIG. 1 is used in structures where wet layup or prepreg angle bonding is not possible in bonding the upper panel and the lip. In this method, the lip 2 is adhered to the lower panel 1 by the wet layup adhesive part 4 or the prepreg angle adhesive part 4, and then the adhesive 7 is applied to the top of the lip 2. After that, the upper panel 8 is covered and applied by applying pressure. The method used in FIG. 1 (b) can be used when wet layup or prepreg angle bonding is possible even after the top panel 8 is covered over the lip 2. After attaching the lip 2 to the lower panel 1 as in (a) of FIG. 1, the upper panel 8 is covered with the upper part of the lip 2, and then wet layup or prepreg angle bonding is performed. This is done.

(C) of FIG. 1 is a side cross-sectional view of the bonding portion of the composite structure shown in (a) or (b) of FIG. As shown partially enlarged, it shows adhesion failure or contact failure that occurs when the top of the lip 2 is not precisely processed according to the curvature of the upper panel. Poor adhesion can cause catastrophic damage to the structure, and poor contact can create stress concentrations that adversely affect the top panel, such as cracking or rupture.

In addition, when a plurality of ribs having different sizes are to be bonded between the same upper panel and the same lower panel, adhesion may be insufficient or a torsional stress due to the adhesion may be formed when the height of each lip is not precisely processed. Can be. FIG. 1D is a cross-sectional side view of a composite structure in which a plurality of ribs are used and bonded according to a conventional method. In such a structure, the structure of the structure is small so that a person cannot enter it, and after bonding, the adhesive is applied to the upper part of the lip (2-1), (2-2), (2-3), and then the top panel (8) is covered and pressed. Done. At this time, for example, when the lip 2-2 is shorter than the other lips 2-1 and 2-3, the upper panel 8 may be attached even when the lip 2-2 is not properly attached or attached. Abnormal stresses can be formed in the Here, the expression of the height of the lip (2) can be applied to the case in which the lip (2) is installed vertically, it was used to include the meaning of the length or width in the case of installing to the left and right.

Adhesion and stability of the bond site are very important factors in structures requiring high structural reliability. In addition, when unwanted internal stresses are formed in the fabrication stage, cracks or fractures may occur at stressed sites when stresses adversely affecting internal stresses during use are applied from the outside. In other words, when used as a structure in the vehicle or aircraft field, the stability of the structure, that is, the safety, should be maintained even in various use environments.

It is an object of the present invention to provide a spring strip for stably bonding a plastic composite structure.

Another object of the present invention is to provide a method for bonding a plastic composite structure which can provide high structural reliability and structural stability by using a spring strip.

(A) of FIG. 1 is a front sectional view of a composite structure bonded according to a conventional method,

(B) of FIG. 1 is a front sectional view of a composite structure bonded according to another conventional method,

(C) of FIG. 1 is a cross-sectional side view of the bonding site of the composite structure shown in (a) or (b) of FIG. 1,

(C) is a cross-sectional side view of a composite structure in which a plurality of ribs are bonded by using a conventional bonding method.

2 is a front sectional view of a composite structure bonded and assembled according to the method of the present invention.

3 is a perspective view showing a flat plate and a layup tool for producing a spring strip according to the present invention. And,

4 is a partial perspective view of the composite structure with the spring strip partially bonded according to the invention.

* Explanation of symbols for main parts of the drawings

1: Lower panel 2, 2-1, 2-2, 2-3: Lip

3: strong adhesive 4: adhesive

5: adhesive 6: spring strip

7: adhesive 8: upper panel

9: assembling tool 10: flat plate

11: spring strip making tool 12: caul plate

Spring composite strip for bonding the plastic composite structure of the present invention for achieving the above object, the inner surface of the upper panel, the lower panel, in order to attach a lip reinforcement installed between the upper panel, the lower panel, the inner surface of the upper panel And interposed between an end of the lip,

And a lip adhesive portion adhered to the end of the lip, and a panel adhesive portion extended from the left and right sides of the lip adhesive portion and plunged to the inner surface of the upper and lower panels.

Plastic composite structure bonding method of the present invention for achieving the above object, the manufacturing method of manufacturing a spring strip having a lip adhesive portion having a predetermined shape, and a panel adhesive portion extended in a state in which a plurality of cut off from the left and right of the lip adhesive portion In the first step, the lower panel is placed on the assembly tool, the second step of erecting the lip thereon and bonding the lower panel and the lower end of the lip, the spring strip produced in the first step is placed on the upper end of the lip, A third step of adhering the top of the lip and the lip bond of the spring strip to each other, a fourth step of applying the adhesive to the panel bond of the top spring strip, and placing the top panel on top of the spring strip and applying pressure until the adhesive has cured It is characterized in that it comprises a fifth step.

And it is preferable that the process of applying pressure in the said 5th step is made using the mold board of an assembly tool.

In addition, it is preferable that the third step is performed before the second step.

Another plastic composite structure bonding method of the present invention for achieving the above object, to produce a spring strip having a lip adhesive portion having a predetermined shape and a panel adhesive portion extended in a plurality of sections cut from the left and right of the lip adhesive portion In a first step, a second step of applying the adhesive to the panel adhesive surface of the spring strip produced in the first step that is precisely positioned and bonded to the lower panel on the assembly tool, the second step of the lower panel A third step of adhering the spring strip, a fourth step of erecting the lip on the spring strip and adhering the lip adhesive portion of the spring strip and the lower end of the lip, and the other spring strip produced in the first step to the upper end of the lip And a fifth step of gluing the upper end of the lip and the lip bond of the spring strip to each other. Where the sixth step, and the upper panel applying an adhesive to the panel bonding portion of the trip spring to the top of the strip and is characterized in that comprises the step 7 which by applying pressure until the adhesive is cured.

And it is preferable that the process of applying pressure in the seventh step is performed using the mold board of the assembly tool.

It is also preferable that the fourth and fifth step operations are performed prior to the second step operation.

By using the method of bonding the spring strip of the present invention and the plastic composite structure using the same, the lip can be flexibly bonded to any panel having any shape or curvature, the area to be bonded can be sufficiently secured, and the adhesion reliability This is guaranteed. In addition, since the sectional processing of the lip or the precision of the lip height is not strictly required, the machining cost and time can be saved accordingly.

Hereinafter, a preferred embodiment of the present invention according to the accompanying drawings will be described in detail.

FIG. 2 is a cross-sectional view of the spring strip according to the present invention applied to the structure, and FIG. 3 is a perspective view showing a flat plate and a layup tool for manufacturing the spring strip, and FIG. 4 is a view in which only a part of the spring strip is bonded. Partial perspective view of a composite structure.

The spring strip 6 for bonding the plastic composite structure according to the present embodiment is attached to the inner surface of the upper and lower panels 1 and 8 with a lip 2 which is a reinforcing material installed between the upper and lower panels 1 and 8. It is to. As shown in the drawing, the spring strip 6 extends with a plurality of lip adhesive parts 6-1 bonded to the ends of the lip 2 and left and right cut off from the left and right sides of the lip adhesive parts 6-1, and the upper and lower panels. The panel bonding part 6-2 adhere | attached on the inner surface of (1,8) is provided.

In more detail, the lower surface of the lip adhesion portion 6-1 of the spring strip 6 is in a state bonded to the upper surface of the lip 2. The lip bond 6-1 located at the center of the spring strip 6 is made in the same shape as the upper section of the lip 2, and both sides of the lip bond 6-1 of the spring strip 6 are paneled. It has a shape cut out at suitable intervals as the panel adhesion part 6-2 which contacts with a. These parts, of course, have a shape already cut at the time of manufacture and are not cut off after making the spring strip 6. The panel bonding portion 6-2 is manufactured in the shape having the cut-out portion as described above, as well as the case in which the panel has a predetermined curvature. ) Can be satisfactorily adhered to the panel. If the panel adhesive part 6-2 does not have a cut-out part, a large part of the panel adhesive part 6-2 is in poor adhesion state when the spring strip 6 is installed crookedly due to a work error on the lip 2. May be adhered to.

In addition, not only the lip adhesion part 6-1 but also the panel adhesion part 6-2 are manufactured according to the curvature of a panel. Basically, the basis of the work is that the panels to be bonded, the shape of the lip (2) or the shape of the spring strip 6 can be said to be made according to the shape of the panels.

Since the spring strip 6 of the present invention is manufactured in the curved shape of the panel adhesive part 6-2, it can serve as a spring which can absorb the error which arises in the process of the lip 2. As shown in FIG. Therefore, the machining error generated at the height of the lip 2, which can generally occur, is sufficiently absorbed and a satisfactory and stable adhesion can be achieved. Of course, even in this case, the lip 2 does not need to be precisely processed, but in view of the thickness of the spring strip 6 itself, etc., it is preferable to process the lip 2 determined as accurately as possible. In other words, when the spring strip 6 absorbs the error of the lip 2, the size is not large but a slight stress is formed in the spring strip 6 itself.

Hereinafter, a method of bonding the composite structure using the spring strip having the above shape will be described in detail.

3 exemplarily shows tools for manufacturing an embodiment of a spring strip according to the invention. The manufacturing method using the illustrated tools is a method that can be manufactured directly in the field in case of non-mass production. In the case of mass production, molds can be manufactured to make them easier and more economical.

First, on the flat plate 10, a spring strip making tool 11 is prepared according to the shape of the spring strip to be manufactured. The illustrated spring strip making tool 11 is for producing a spring strip having a shape in which the lip contact of the spring strip is parallel to the plate for convenience. The shape of the spring strip making tool 11 may have various shapes depending on the shape of the spring strip required. In other words, if the lip adhesive has a certain curvature, the shape of the spring strip making tool 11 should be manufactured according to the curvature.

Once the spring strip making tool 11 is provided, the spring strip can be made accordingly. In this case, since the surfaces of the spring strips to be bonded should be particularly smooth and uniform, a caul plate 12 may be used for this purpose. The call plate 12 is an auxiliary tool typically used to smoothly surface the surfaces used for precise bonding operations among the surfaces not in contact with the tool. The spring strip 6 is manufactured to be about 2 to 4 plies so as to be flexible and well bent.

And the assembly tool 9 which matches the curvature of the lower panel 1 is provided, and the lower panel 1 is correctly fitted and fixed on this assembly tool 9. The lip 2 is then erected at a predetermined position of the lower panel 1 and a strong adhesive 3 such as an epi bond is applied to the lower end of the lip 2 and the contact edge of the lower panel 1. After the strong adhesive 93 is cured, the adhesive portion 4 is formed by the wet layup method in an angle shape at the corner portion where the lip 2 and the lower panel 1 contact each other. The wet layup method is a widely used method for joining a single component and a single component made of a composite material. The resin-impregnated resin and impregnated elastic fibers and glass fibers are laminated several times on the bonding site and then hardened. will be. Most of these wet layup methods are by hand.

After the adhesive portion 4 by the wet layup is cured, the adhesive 5 is applied to the upper end of the lip 2 and the lip adhesion surface 6-1 of the spring strip 6, and then the upper end of the lip 2. The lip adhesive side of the spring strip 6 to match. The adhesive 7 is then filled in the lip bond 6-1 and the panel bond 6-2 on the top of the spring strip 6 bonded to the lip 2, and the top panel 8 is spring-striped. Covered with the panel bonding part 6-2 of (6), the structure is hold | maintained under pressure by the assembly tool 9 so that the overall shape of a panel may be maintained. Once the bonding site has cured, the bonding work on the structure is complete.

Meanwhile, in the above-described process step, the step of adhering the spring strip 6 to the upper end of the lip 2 may be performed first. At this time, which process should be performed first is determined by the convenience of work.

The role of the spring strip 6 constituting the most important part of the present invention is that the part bonded to the top of the lip 2 and the part bonded to the upper panel in the spring strip 6 as can be seen in FIG. Since it can be variable within a certain range like a spring, it is possible to sufficiently absorb the errors generated in the machining of the lip 2 itself. In addition, since the area to be bonded can be sufficiently provided as necessary, a very stable and reliable bonding can be achieved. Of course, the spring strip 6 is in a constant state and is not variable once it is adhered to the top panel 8 and the adhesive has cured.

As described above, the use of the spring strip 6 only on the upper adhesive site side ensures that the adhesion between the lower panel 6 and the lip 2 does not have a problem of an error occurring at the height of the lip 2, and is easy to work with. Because. Moreover, it can be used when the curvature of the lower panel 1 is not large, or when the shape of the lower panel 1 is not complicated. In this case the contact surface of the lip 2 in contact with the lower panel 1 should be machined to an appropriate level.

Here, the method of forming the adhesive part 4 by the wet layup method is used in the method of bonding the lip 2 to the lower part 1, but the method of adhering the lip 2 to the prepreg angle or other methods is not excluded. The material used in the case of using the wet layup method is, for example, glass fiber No. 181 or No. 1581 is used, and work to be about 4 plies.

According to another embodiment of the present invention, a spring strip can be used between the lip and the lower panel as well as between the lip and the upper panel. Although the drawings related to this embodiment have been omitted, the same operation as in the case of using one spring strip is performed twice, and can be easily understood with reference to FIGS. 2 and 4. In the case where the spring strip 6 of the present invention can be mass-produced, the use of the spring strip 6 also between the lower panel 1 and the lip 2 makes it possible to achieve easy and stable bonding effect.

However, it is to be ensured that unnecessary loads are not applied to the spring strip used at the bottom of the work. Of course, although the lip 2 made of plastic composite is lightweight, it would be desirable to minimize the effect of the load on the lip 2 as well.

As described above, by the spring strip of the present invention and the plastic composite structure bonding method using the same, it is possible to structurally absorb errors due to lip processing, etc. to prevent the formation of stress that may occur during the bonding operation to the panel to be bonded In addition, it is possible to achieve a reliable and reliable adhesion.

Claims (7)

In the spring strip for bonding the plastic composite structure interposed between the inner surface of the upper panel and the lower panel and the end of the lip, in order to attach a rib, which is a reinforcing material installed between the upper panel and the lower panel, to the inner surface of the upper panel and the lower panel. A spring strip for bonding a plastic composite structure comprising a lip adhesive part adhered to an end of a lip, and a panel adhesive part extending from the right and left sides of the lip adhesive part and plunged to the inner surface of the upper and lower panels. . In the first step of manufacturing a spring strip having a lip adhesive portion having a predetermined shape and a panel adhesive portion extended in a plurality of sections cut from the left and right sides of the lip adhesive portion, the lower panel is placed on the assembly tool, and then the lip is placed thereon. A second step of adhering the lower panel and the lower end of the lip, a third step of placing the spring strip fabricated in the first step on the upper end of the lip and adhering the upper end of the lip and the lip adhesive of the spring strip to each other; A fourth step of applying an adhesive to the panel adhesive of the spring strip, and a fifth step of placing the top panel on top of the spring strip and applying pressure until the adhesive has cured. Method of bonding plastic composite structures. The method of bonding a plastic composite structure using a spring strip according to claim 2, wherein the step of applying pressure in a fifth step is performed by using a mold board of an assembly tool. 3. The method of claim 2, wherein the third step operation is performed prior to the second step operation. A first step of manufacturing a spring strip having a lip adhesive part having a predetermined shape and a panel adhesive part extended in a plurality of sections cut from the left and right sides of the lip adhesive part; A second step of applying adhesive to the panel adhesive surface of one spring strip fabricated in the first step, a third step of adhering the spring strip of the second step to the lower panel, a lip on the spring strip A fourth step of adhering the lip adhesive part of the lip to the lower end of the lip, and placing another spring strip fabricated in the first step on the upper end of the lip, and adhering the upper end of the lip and the lip adhesive part of the spring strip to each other; Step 5, applying the adhesive to the panel adhesive of the top spring strip, and step 6 attaching the top panel to the top of the spring strip. Value and the method of bonding plastic composite structures with the spring strip, characterized in that comprises the step 7 that the applied pressure until the adhesive is cured. The method of claim 5, wherein the step of applying pressure in the seventh step is performed by using a mold board of the assembly tool. 6. The method of claim 5, wherein said fourth and fifth operations are performed prior to said second operations.