Framework type composite material arm structure and preparation method thereof

Abstract

The invention provides a skeleton type composite material arm structure and a preparation method thereof.The skeleton type composite material arm structure comprises an upper connecting plate and a lower connecting plate, a plurality of strip-shaped inner skeletons are arranged between the upper connecting plate and the lower connecting plate, and the surfaces of the inner skeletons are coated with prepregs to form inner skeleton coating layers; and the outer surface of the inner framework coating layer is coated with prepreg to form an outer coating layer. The framework type composite material arm structure is a mold-free composite material arm structure, the framework type structure can be expanded to adapt to mold-free composite material structures in various shapes, and the problem of improvement of a lightweight structure of an existing structural arm at present is solved.

Description

Technical Field

[0001] This invention belongs to the field of composite materials, and in particular relates to a skeleton-type composite material arm structure and its preparation method. Background Technology

[0002] In the robot industry, the robot body structure requires a large number of arm components, which bear the main motion loads of the robot. As the performance requirements of robot products continue to increase, the demand for lightweight motion components is also constantly rising. Current arm products include: machined metal arms, cast metal arms, composite material tube and metal assembly arms, and manually laid-up composite material arms. Among these, machined metal arms and cast metal arms are heavy and unsuitable for products requiring overall lightweighting; composite material tube and metal assembly arms are lighter than metal arms, but the overall assembly is more cumbersome and the metal content is higher, resulting in a larger overall weight, requiring further lightweighting improvements; manually laid-up composite material arms, however, require a lot of manual laying, resulting in low overall efficiency, high initial mold investment, and a long development cycle. In summary, existing machined metal arms, cast metal arms, composite material tube and metal assembly arms, and manually laid-up composite material arms cannot meet the requirements of high load-bearing capacity, lightweighting, low R&D costs, and short development cycles. Summary of the Invention

[0003] In view of this, the present invention aims to overcome the defects in the prior art and proposes a skeleton-type composite material arm structure and its preparation method. This arm structure is a lightweight, high load-bearing, and moldless carbon fiber robot arm structure that balances positive and lateral rigidity, and has the advantages of lower development cost, shorter development cycle, higher load-bearing capacity, and lightweight.

[0004] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0005] In a first aspect, the present invention provides a skeleton-type composite material arm structure, including an upper connecting plate and a lower connecting plate, wherein a plurality of strip-shaped inner skeletons are provided between the upper connecting plate and the lower connecting plate, the surface of the inner skeletons is covered with prepreg to form an inner skeleton covering layer, and the outer surface of the inner skeleton covering layer is covered with prepreg to form an outer covering layer.

[0006] Furthermore, both the upper and lower connecting plates are provided with a number of mounting holes for installing the inner frame.

[0007] Furthermore, the two ends of the inner frame are connected and fixed to the upper connecting plate and the lower connecting plate by welding or bonding.

[0008] Furthermore, the inner skeleton covering layer and the outer skeleton covering layer are made of a resin matrix with added reinforcing materials.

[0009] Furthermore, the reinforcing fiber is one or more of carbon fiber, aramid fiber, glass fiber, and basalt fiber.

[0010] Furthermore, the resin matrix is ​​one or more of epoxy resin, phenolic resin, and cyanate ester resin.

[0011] Furthermore, the inner frame is made of bamboo, wood, metal wire, or metal pipe.

[0012] Secondly, the present invention provides a method for preparing a skeleton-type composite material arm structure, comprising the following steps:

[0013] S1. The inner skeleton is made by manual bending, welding, or gluing.

[0014] S2. A prepreg prepared using a resin matrix mixed with reinforcing materials is used to coat the inner skeleton to form an inner skeleton coating layer, and then heat shrink tape is used to coat the inner skeleton coating layer to form an inner skeleton composite preform.

[0015] S3. Heating and curing the inner skeleton composite preform, removing the heat shrink tape after curing, and grinding and cleaning the surface to obtain the inner skeleton composite.

[0016] S4. Machining the upper and lower connecting parts, inserting several inner skeleton composites into the corresponding holes of the upper and lower connecting plates and fixing them to obtain the inner skeleton frame;

[0017] S5. Use prepreg to cover the outer surface of the inner skeleton frame to form an outer covering layer, thus obtaining the initial preform of the product.

[0018] S6. Insert the inner bladder into the inner cavity of the product preform, inflate it until it fits the inner cavity, and cover the outer surface of the preform with heat shrink tape to obtain the product preform.

[0019] S7. Heat and solidify the product preform to obtain the initial product form;

[0020] S8. The product is initially polished, cleaned, machined, and coated with a powder coating to obtain the final product.

[0021] Furthermore, the upper and lower connectors are obtained by machining, waterjet cutting, or laser cutting.

[0022] Furthermore, after the inner skeleton composite is fixed to the upper connector and the lower connector by adhesive, the inner skeleton frame is obtained after the adhesive cures.

[0023] Furthermore, the prepreg used in steps S2 and S5 is mixed with a resin matrix containing reinforcing materials.

[0024] Furthermore, the reinforcing fiber is one or more of carbon fiber, aramid fiber, glass fiber, and basalt fiber.

[0025] Furthermore, the resin matrix is ​​one or more of epoxy resin, phenolic resin, and cyanate ester resin.

[0026] Furthermore, the inner frame is made of bamboo, wood, metal wire, or metal pipe.

[0027] When lightweighting is a critical requirement for products, composite materials such as carbon fiber often have thinner layup designs. In such cases, traditional uniform layup methods require increasing the layup thickness on all surfaces simultaneously to achieve increased stiffness under multi-directional stress, which reduces fiber stiffness. Furthermore, the overall thinness leads to excessive corner stress during accidental impacts, increasing the risk of damage. When subjected to both downward and inward (or outward) loads, fiber reinforcement along the edge contour can improve stiffness in both directions. Simple local thickening can increase fiber stiffness utilization, but its small cross-section results in poor local stability. This invention utilizes a skeletal frame structure to effectively improve product stability, better leveraging the contribution of edge contour stiffness while ensuring the product does not become unstable due to insufficient strength in other areas.

[0028] Compared with the prior art, the present invention has the following advantages:

[0029] (1) The present invention presents a moldless composite material arm structure. In order to solve the problem of improving the lightweight structure of existing structural arms, the structure of the present invention mainly highlights the simple molding of the main body outline. At the same time, the overall structural deformation resistance of the robotic arm under various stress states (bending resistance, torsion resistance) can be taken into account through the layering design.

[0030] (2) The skeleton structure proposed in this invention can be extended to adapt to various shapes of moldless composite material structures. Attached Figure Description

[0031] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0032] Figure 1 This is a cross-sectional view of a skeleton-type composite material arm structure (arc arm);

[0033] Figure 2 This is a schematic diagram of the overall structure of the internal skeleton complex.

[0034] Figure 3 for Figure 1 A magnified view of a section at point A in the middle;

[0035] Figure 4 This is a cross-sectional view of the internal skeleton complex;

[0036] Figure 5 This is a structural diagram of the internal skeleton frame;

[0037] Figure 6 This is a schematic diagram of the product preform structure;

[0038] Figure 7 for Figure 6 A magnified view of a section at point B in the middle;

[0039] Figure 8 This is a schematic diagram of the overall structure of the skeleton-type composite material arm structure (straight arm).

[0040] Explanation of reference numerals in the attached figures:

[0041] 1. Upper connecting plate; 2. Lower connecting plate; 3. Inner skeleton; 4. Inner skeleton covering layer; 5. Outer covering layer; 6. Inner skeleton composite; 7. Heat shrinkable tape A layer; 8. Inner bladder; 9. Heat shrinkable tape B layer. Detailed Implementation

[0042] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0043] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0044] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0045] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0046] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0047] The prepregs used in the examples were manufactured by Xi'an Kangben Materials Co., Ltd., and were selected from commercially available prepregs of models PF401 / 3CP(H)200, PF051 / 12CPZK200, and WP2201 / FAW1500.

[0048] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0049] Example

[0050] This embodiment 1 is a skeleton-type composite material arm structure, such as Figures 1-7 As shown, the system includes an upper connecting plate 1 and a lower connecting plate 2. Several strip-shaped inner skeletons 3 are disposed between the upper connecting plate 1 and the lower connecting plate 2. The surface of the inner skeleton 3 is covered with prepreg to form an inner skeleton covering layer 4, and the outer surface of the inner skeleton covering layer 4 is covered with prepreg to form an outer covering layer 5. Both the upper connecting plate 1 and the lower connecting plate 2 have several mounting holes for installing the inner skeletons 3. The two ends of the inner skeleton 3 are connected and fixed to the upper connecting plate 1 and the lower connecting plate 2 by welding or bonding.

[0051] Taking the articulated frame composite material arm structure as an example, such as Figures 1-7 As shown, the fabrication process of this skeleton-type composite material arm structure is as follows:

[0052] S1. Inner skeleton processing: Using bamboo, wood, metal wire or metal pipe, the inner skeleton 3 is obtained by manual bending, welding and splicing, gluing and splicing, etc., according to the shape of the inner skeleton 3.

[0053] S2. Processing of the inner skeleton composite preform:

[0054] The inner skeleton 3 is covered with a prepreg made by mixing reinforcing materials and resin matrix materials, and then heat shrink tape is used to cover the inner skeleton covering layer to form an inner skeleton composite preform 6.

[0055] S3, Inner skeleton composite processing:

[0056] The inner skeleton composite preform 6 is heated and cured. After curing, the heat shrink tape covering layer A 7 is removed, and the surface is polished and cleaned to obtain the inner skeleton composite 6, as shown. Figure 2 and Figure 4 As shown;

[0057] S4. Upper connector 1 processing: Using metal or composite materials, the upper connector 1 is processed according to its specific dimensions by machining, water jet cutting, laser cutting, or other methods.

[0058] S5. Machining of lower connector 2: Using metal or composite materials, the lower connector 2 is machined to its specific dimensions using machining, water jet cutting, laser cutting, or other methods.

[0059] S6. Inner frame processing: according to... Figure 4 Multiple internal skeleton composites 6 are inserted into the corresponding holes of the upper connecting plate 1 and the lower connecting plate 2 and fixed with heat-resistant adhesive. After the adhesive cures, the internal skeleton frame is obtained, as shown below. Figure 5 As shown;

[0060] S7. Overall Covering: A prepreg made using reinforcing materials such as carbon fiber, aramid fiber, glass fiber, and basalt fiber, and matrix materials such as epoxy resin, phenolic resin, and cyanate ester resin. An overall outer covering layer 5 is applied to the inner skeleton frame to obtain the initial preform of the product.

[0061] S8. Initial Shaping: An inner bladder 8 made of flexible materials such as rubber or plastic is placed inside the initial shaping cavity of the product. It is inflated until it conforms to the inner shape. Heat-shrinkable tape (layer B 9) is then wrapped around the outside of the initial shaping cavity (excluding the top and bottom surfaces) to obtain the pre-shaped product. Figure 6 and Figure 7 As shown.

[0062] S9. Place the product preform into an oven or autoclave and heat it to cure to obtain the product prototype.

[0063] S10. The product is initially polished, cleaned, machined, and coated with a surface coating to obtain the final product.

[0064] Of course, a straight-arm skeleton composite material arm structure can be prepared according to the above preparation process. The only difference is that the inner skeleton is straight, such as... Figure 8 As shown.

[0065] The skeleton-type composite material arm structure of the present invention is a moldless composite material arm structure. This skeleton-type structure can be extended to adapt to various shapes of moldless composite material structures, solving the problem of lightweight structural improvement of existing structural arms.

[0066] This invention effectively improves product stability through a skeletal frame structure, ensuring that the product does not become unstable due to insufficient strength in other areas while better utilizing the contribution of edge contour stiffness.

[0067] The skeleton-type composite material arm structure of the present invention highlights the structural strength of the contour line, effectively improving the overall structural deformation resistance of the carbon fiber arm under various stress states (downward, inward or outward simultaneous stress), while also improving the safety of the product in accidental collisions.

[0068] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A framework composite arm structure, characterized by: The upper connecting plate and the lower connecting plate are provided with a plurality of strip-shaped inner skeletons between them, the surface of the inner skeletons is covered with prepreg to form an inner skeleton covering layer, and the outer surface of the inner skeleton covering layer is covered with prepreg to form an outer covering layer.

2. The framework composite arm structure according to claim 1, characterized by: The upper connecting plate and the lower connecting plate are provided with a plurality of mounting holes for mounting the inner skeletons.

3. The framework composite arm structure of claim 1, wherein: The two ends of the inner skeletons are connected and fixed with the upper connecting plate and the lower connecting plate by welding or bonding.

4. The framework composite arm structure of claim 1, wherein: The material of the inner skeleton covering layer and the outer skeleton covering layer is a resin matrix added with reinforcing materials.

5. The framework composite arm structure of claim 1, wherein: The reinforcing fibers are one or more than two of carbon fibers, aramid fibers, glass fibers and basalt fibers; and the resin matrix is one or more than two of epoxy resin, phenolic resin and cyanate ester resin.

6. The framework composite arm structure of claim 1, wherein: The material of the inner skeletons is bamboo, wood, metal wire or metal pipe.

7. A method of making a framework composite arm structure, characterized by: The method comprises the following steps: S1, using a manual bending, welding splicing or bonding splicing processing method to obtain the inner skeletons; S2, using the prepreg prepared by mixing the resin matrix with the reinforcing materials to cover the inner skeletons to form the inner skeleton covering layer, and then using the heat-shrinkable tape to cover the outer surface of the inner skeleton covering layer to form the inner skeleton composite preform; S3, heating and curing the inner skeleton composite preform, removing the heat-shrinkable tape after curing, and polishing and cleaning the surface to obtain the inner skeleton composite; S4, processing the upper connecting piece and the lower connecting piece, loading a plurality of inner skeleton composites into the corresponding holes of the upper connecting plate and the lower connecting plate and fixing to obtain the inner skeleton frame; S5, using the prepreg to integrally cover the outer surface of the inner skeleton frame to form the outer covering layer, and obtaining the preformed product; S6, placing the inner capsule in the inner cavity of the product and inflating it to fit the inner cavity, using the heat-shrinkable tape to cover the outer surface of the product to obtain the product preform; S7, heating and curing the product preform to obtain the product; S8, polishing, cleaning, machining and surface spraying the product to obtain the final product.

8. The method of claim 7, wherein: The upper connecting piece and the lower connecting piece are obtained by machining, water cutting or laser cutting.

9. The method of claim 7, wherein: The inner skeleton frame is obtained after the inner skeleton composite is connected and fixed with the upper connecting piece and the lower connecting piece by the bonding glue, and the bonding glue is cured.

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