KR100715427B1 - Composite-metal lightweight boom assembly - Google Patents

Abstract

The present invention relates to a lightweight boom assembly, and more particularly, to a boom assembly that is made of a composite material and a metal material to achieve a light weight and at the same time secure the necessary rigidity.

The lightweight boom assembly according to the invention comprises a boom, a boom pipe, an actuator and a connecting pin. The boom pipe includes a hollow tube made of a composite material, a liner bonded to the inner surface of the tube, and a metal cover bonded to the outer surface of the tube. Further comprising a metal boss coupled to the outer diameter surface of the metal cover at the longitudinal end of the tube by any one method selected from interference fit, shrink fit or adhesion.

According to the present invention, since each component of the boom assembly has a metal cover and the internal composite material is protected by the metal cover, the environmental resistance and impact resistance can be improved without lowering the lightening effect of each component of the boom assembly. It can improve the safety and durability.

Cranes, pump cars, booms, actuators, rods, connecting pins, composites, metal covers.

Description

Lightweight Boom Assembly with Composites and Metals {COMPOSITE-METAL LIGHTWEIGHT BOOM ASSEMBLY}

1 is a cross-sectional view of a boom of one embodiment of a lightweight boom assembly according to the present invention;

2 is a cross-sectional view of a boom of another embodiment of a lightweight boom assembly according to the present invention;

3 is a cross-sectional view of a boom of another embodiment of a lightweight boom assembly according to the present invention;

4 is an explanatory diagram showing a method of manufacturing a boom of a lightweight boom assembly according to the present invention using RTM,

5 is a cross-sectional view of the boom pipe of one embodiment of a lightweight boom assembly according to the present invention;

6 and 7 are partially enlarged cross-sectional views of the metal boss coupling portion of the boom pipe of FIG.

8 is a cross-sectional view of an actuator rod of one embodiment of a lightweight boom assembly according to the present invention,

9 is a cross-sectional view of a connecting pin of one embodiment of a lightweight boom assembly according to the present invention;

10 and 11 are partially enlarged cross-sectional views of the annular boss coupling portion of the connecting pin of FIG.

♣ Explanation of symbols for main parts of drawing ♣

101, 201, 301: Hollow beam 102, 202, 302: Metal cover

303: foam core 501, 601, 701: tube

503, 603, 703: liner 604, 704: metal boss

901, 1001, 1101: composite material 902, 1002, 1102: metal tube

1003, 1103: annular boss

The present invention relates to a lightweight boom assembly, and more particularly, to a boom assembly that is made of a composite material and a metal material to achieve a light weight and at the same time secure the necessary rigidity.

The boom assembly consists of a plurality of booms, actuators for telescopicing the boom, and components such as connecting pins for forming articulation of the boom or connecting the actuator and the boom. Concrete pump cars also add components to the boom assembly, such as boom pipes, which provide the transport path for concrete. As buildings rise in recent years, boom assemblies installed in special vehicles such as pump cars, crane cars, and fire trucks have also become larger. However, when the boom assembly is enlarged, the weight of the truck increases due to the increase in the weight of the boom assembly, which requires the enlargement of the drive engine and the reinforcement of the suspension, and the hydraulic type to withstand the moment received by the body and the boom support when the boom is extended. Reinforcement work on the body support must be accompanied. In addition, there is a risk of increasing the breakage of the vehicle equipped with the boom assembly to increase road damage. Therefore, there is a limit to increasing the size of a general steel boom assembly unless proper measures for weight reduction at the same time as the size of the boom assembly are taken.

As a method for reducing the weight of the boom assembly, a design technology using fiber-reinforced composite materials replacing the existing metal materials is attracting attention. Fiber-reinforced composites have not only high specific stiffness (rigidity / weight) and specific strength (strength / weight), but also excellent vibration damping and shock absorption. In addition, since the characteristics have different anisotropy according to the direction, there are various advantages that can maximize the directivity through the appropriate design. Applying such a composite material to each component of the boom assembly can significantly improve the structural stability and weight.

U.S. Patent Nos. 6,786,233, 6,755,212, 6,719,009, U.S. Patent Nos. 20050011560, and 20050011604 propose metal booms or integral fiber reinforced composite booms reinforced with fiber reinforced composites. The beam-shaped boom structure in which fiber reinforced composite materials are bonded to the upper and lower surfaces or all four sides of the existing metal square beam has the advantage of increasing the bending stiffness of the boom, but the weight reduction effect is low. In addition, in a boom mixed with a composite material and aluminum, a structure in which a fiber reinforced composite material is wrapped on an outer surface of the mandrel and a layer of aluminum honeycomb, aramid composite, and glass fiber composite layer is laminated Compared with the boom, it is expected to achieve higher weight and bending stiffness. However, the structure is very complicated, the manufacturing process is difficult, and the productivity is low. In addition, since both structures are structures in which the composite material is exposed on the outer surface, cracks may be generated due to external impact on the resin, which is the base of the composite material, or property degradation due to ultraviolet rays or chemicals may occur.

Korean Patent No. 10-0235057 proposed a method of manufacturing a square hollow beam by laminating and curing a composite prepreg on the outer surface of a mandrel or a female tool. Korean Patent No. 10-203804 proposes a composite boom in which a hollow composite material boom using a filament winding and two beams of a 'c' shape having a reinforcing member attached thereto are bonded by bolts or adhesives. It was. Compared with the hollow beam, the 'c' shaped beam can be easily manufactured by vacuum bag molding or compression molding, but has a disadvantage of weakening at the joint. In addition, as in the US patent, the composite material is exposed to the outer surface, which is vulnerable to external shock, and there is a fear of deterioration of physical properties due to environmental changes.

The following inventions have been proposed in connection with the weight reduction of the boom pipe among the components of the boom assembly. In US Patent Publication No. 20040228739, a method of manufacturing a concrete transport pipe made of a composite material and reducing its weight has been proposed. The US patent manufactures a method of bonding a composite material using filament winding to a liner having excellent abrasion resistance such as urethane, and bonding metal couplings at both ends with a urethane adhesive, which is lighter than conventional metal pipes. This has the effect of improving the dynamic stability of the boom structure. However, the composite pipe manufactured by filament winding has low productivity, the outer surface is not uniform and the composite material is exposed to the outside, which may cause cracks due to external impact or deterioration of properties due to ultraviolet rays or chemicals. In addition, although US Patent Publication No. 20040145180 proposes a structure in which a metal coupling is bonded to a composite pipe made of a reinforcing layer, a reinforcing layer, and a wear resistance layer, similarly to the present invention, there is a concern about deterioration of physical properties of the composite material. In Korean Utility Model Registration No. 20-0156328, a metal boss of both ends is bonded to a polymer or ceramic liner, and a filament winding is used to laminate and cure the glass fiber impregnated with epoxy. Glass fiber / epoxy composites have the advantage of being translucent to observe the abrasion state of the dark inner liner, but still have the disadvantage that the composites are visible. Korean Utility Model Utility Model No. 20-0206041, Utility Model Registration No. 20-0156329, Utility Model Registration No. 20-0156328, and Korean Utility Model Registration No. 1998-045513, which have proposed similar structures, have problems that composite materials are exposed to the outside. have.

Large hydraulic actuators are also a major component of the boom assembly. Therefore, the weight reduction of the large hydraulic actuator can greatly improve the structural stability. In US Pat. No. 5,435,868, a hydraulic cylinder is manufactured by inserting cylindrical wax into a part to be formed into an empty space of a metal shaft, arranging bearings and seals to be mounted on an actuator, and filament winding. In this form, both the thread and the flange are made of composite material, so that local damage may occur due to stress concentration and the pressure resistance limit is low. U.S. Patent No. 4,777,869 uses composite materials for both the piston rod and the cylinder and is manufactured by filament winding, which is very lightweight, but the rod and cylinder shape is complex, making the fibers difficult to arrange and the process complicated. In addition, there is a disadvantage that a separate coating process for adjusting the outer diameter of the piston rod and the inner diameter of the cylinder is uneven surface.

As described above, the problem of the fiber-reinforced composite lightweight boom assembly according to the prior art is that the composite material is exposed to the outer surface, there is a risk that the composite material is damaged by an external impact or environment. In addition, there is a problem that the manufacturing process is difficult and difficult to manufacture a large structure.

Therefore, the present invention is to solve the above problems, the object of the present invention is to reduce the damage of the composite material by bonding the metal cover to the outer surface of the composite material at the same time to achieve a light weight of the boom assembly using a fiber-reinforced composite material It is to provide a boom assembly that can.

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The lightweight boom assembly according to the present invention is a boom assembly including a boom, a boom pipe, an actuator, and a connecting pin, wherein the boom pipe is joined to a hollow tube made of a composite material and an inner surface of the tube. And a metal cover bonded to the liner and the outer surface of the tube. It is preferable to further include a metal boss coupled to the outer diameter surface of the metal cover at the longitudinal end of the tube by any one method selected from interference fit, shrink fit or adhesion. In addition, the metal cover is shorter than the tube body, and covers the end of the tube projecting to both ends of the metal cover and a portion of the end of the metal cover is coupled by any one method selected from interference fit, shrink fit or adhesion. It is preferable to further include a metal boss. And the liner is preferably made of any one selected from polymer, rubber, metal or ceramic.

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Hereinafter, exemplary embodiments of the boom assembly according to the present invention will be described in detail with reference to the accompanying drawings.

1 and 2 show a cross section of a boom of one embodiment of a lightweight boom assembly according to the present invention. The outer surface is made of a metal cover, and the metal cover is manufactured by welding four metal plates 102 as shown in FIG. 1 or bending a thin metal plate 202 as shown in FIG. Hollow beams 101 and 201 made of fiber-reinforced composite materials are bonded to the inner surface of the metal cover to support most loads, and the metal cover is used as a protective layer of the inner beams 101 and 201. In addition, as shown in FIG. 3, it is preferable to form a foam core 303 by filling a hollow in the hollow of the beam 301.

The boom of such a structure is manufactured by attaching or winding a thin metal sheet 202 on the outer surface of the hollow beams 101 and 201 made of filament winding or pultrusion, or bonding the thin iron plate 102 to an adhesive bond. Or it can be manufactured by fixing with rivets or bolts. In addition, in the hollow of the boom, as shown in FIG. 3, a foam core 303 is formed and a prepreg is wound thereon to form a beam 301 filled with the hollow foam core, and bent to the outside of the beam. The thin metal plate 302 may be wrapped, or may be manufactured by co-curing the thin metal plates divided into several pieces. In addition, as shown in FIG. 4, after the metal cover 402 is welded, bent or riveted to make a tubular shape, the reinforcing fiber fabric 401 is arranged inside the tubular shape and a tubular vacuum bag made of polymer material ( Resin Transfer Molding (RTM) which inserts and seals the metal cover and the vacuum bag at both ends in the longitudinal direction with a sealant (404), and injects resin at one end in the longitudinal direction and sucks air at the other end. It is also possible to manufacture a boom using. In this case, the outer metal cover 402 may be used as an outer mold for the RTM, but when the metal cover 402 is deformed too thin, a separate outer mold may be added to the outside of the metal cover 402. Although the cross-sectional shape of the boom has been described above as being rectangular, it is obvious that the boom can be applied to a boom having a cross section, such as a circle or an ellipse, in addition to the rectangle.

5 is a cross-sectional view of the boom pipe of one embodiment of a boom assembly according to the present invention. The metal cover 502 is joined to the outer circumferential surface of the tubular body 501 made of a fiber reinforced composite material. The inner surface of the tubular body 501 is bonded with a liner 503 made of polymer, rubber, ceramic, or metal to prevent damage to the composite material caused by the conveyed material. Both ends of the boom pipe are provided with bosses 604 and 704 as shown in FIGS. 6 and 7 for coupling between the pipes, and the bosses are joined to the boom pipe through a method of pressing, adhesive bonding or shrink fit. The outer metal covers 602 and 702 are bonded to the tubular body 501 using an adhesive or co-curing method, but as shown in FIG. 7, the metal cover 702 is not directly joined to the tubular body 701, as shown in FIG. 7. It may also be manufactured in a structure that is constrained by the boss 704 coupled to it.

The liners 503, 603, and 703 are made of polymer, ceramic, or metal, and are manufactured by co-curing or forming a tubular body first and then bonding using an adhesive when manufacturing a boom pipe. The outer metal covers 502, 602 and 702 may be manufactured by forming a tube body and then bonding the thin metal plate to the tube body or bonding the tube body to the inside of the thin metal tube, and attaching the metal plate or tube to the tube body. Both ends of the metal cover may be inserted into the boss without being directly bonded to each other and may be manufactured to have a structure constrained by the boss.

The structure of the boom pipe according to the invention can also be applied to the cylinder for the actuator. That is, the actuator cylinder includes a tubular body made of a composite material, similar to a boom pipe, a metal cover joined to the outer surface of the tubular body, and a liner joined to the inner surface of the tubular body. In this case, the inner surface of the cylinder should be flawless and have high dimensional accuracy, so the liner is preferably made of a metal pipe. In order to bond the outer metal cover, a composite prepreg is wound around the inner liner, that is, a metal pipe, or a filament winding is formed to form a tube, and then a thin metal sheet is co-cured on the outer surface of the tube. In the case of using the metal tube as an outer metal cover, after forming the tube, an adhesive may be applied to the inside of the metal tube, and the tube may be manufactured by inserting the tube into the metal tube and bonding the tube.

8 is a cross-sectional view of the actuator rod of one embodiment of a boom assembly according to the present invention. The actuator rod is similar in structure to the boom pipe according to the present invention, except that there is no liner therein. In the case of the rod for the actuator, the outer surface of the rod should be flawless and have high dimensional accuracy, so it is manufactured using the metal pipe 802. The composite material prepreg 801 may be laminated on the inner surface of the metal pipe and bonded by co-curing. In addition, the composite prepreg is wound around the outer surface of a circular foam core or polymer or rubber insert having a large coefficient of thermal expansion, and then inserted into a metal pipe and cured, thereby molding the prepreg by consolidation by thermal expansion of the inner core or insert. You can also use the method.

9 is a cross-sectional view of the connecting pin of one embodiment of a boom assembly according to the present invention. Since connecting pins must have excellent wear resistance and hardness, a flawless metal must be located outside. The connecting pin is thus composed of an outer metal tube 902 and an inner composite layer 901. In order to bond the internal composite material, a prepreg may be wound around the inner surface of the processed metal tube 902 and co-cured, or an adhesive may be applied to an already formed composite tube and inserted into the metal tube to cure. .

The outer metal tube may not only be configured as one body as shown in FIG. 9, but may also have a form in which the end portions are separately processed and coupled as shown in FIGS. 10 and 11. This type of advantage is easy to process the metal cover, there is an advantage that can block the end of the inner composite material with the external environment. That is, as shown in Fig. 10, in the coupling of the annular boss 1003 to both ends of the metal tube 1002 to which the composite material 1001 is bonded, it can be bonded using shrinkage or adhesive. As another joining method, as shown in FIG. 11, a thread is processed at both ends of the metal tube 1102 and a composite material 1101 is bonded therein, and then the annular boss 1103 is screwed. .

An embodiment of the present invention described above and illustrated in the drawings should not be construed as limiting the technical idea of the present invention. The protection scope of the present invention is limited only by the matters described in the claims, and those skilled in the art can change and change the technical idea of the present invention in various forms. Therefore, such improvements and modifications will fall within the protection scope of the present invention, as will be apparent to those skilled in the art.

According to the present invention, since each component of the boom assembly has a metal cover and the internal composite material is protected by the metal cover, the environmental resistance and impact resistance can be improved without lowering the lightening effect of each component of the boom assembly. It can improve the safety and durability.

Claims (12)

delete delete In a boom assembly comprising a boom, a boom pipe, an actuator, and a connecting pin, The boom pipe, Hollow tube made of composite material, A liner bonded to an inner surface of the tubular body, And a metal cover bonded to the outer surface of the tubular body. The method of claim 3, And a metal boss coupled to the outer diameter surface of the metal cover at the longitudinal end of the tube by any one method selected from interference fit, shrink fit or adhesion. The method of claim 3, The metal cover has a length shorter than that of the tube body, and covers the end of the tube projecting to both ends of the metal cover and a part of the end portion of the metal cover, and is joined by any one method selected from interference fit, shrink fit, or adhesion. A boom assembly further comprising a boss. The method of claim 3, And the liner is any one selected from polymer, rubber, metal or ceramic. delete delete delete delete delete delete

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