Forming method of local convex structure of workpiece, arm support machine, fiber composite material workpiece and production method of fiber composite material workpiece

Abstract

The invention relates to the field of fiber composite material workpieces, and discloses a forming method of a local protruding structure of a workpiece, a cantilever crane machine, the fiber composite material workpiece and a production method of the fiber composite material workpiece, the forming method comprises a secondary core mold installation step (S1), a fiber winding step (S2) and a secondary rigid outer mold installation and heating curing step (S3), the secondary forming core mold (4) is fixedly connected to a preset position of the workpiece main body (3); the fiber yarns infiltrated with the resin are spirally wound to form a fiber composite material layer, then a secondary rigid outer mold (5) is installed, then the secondary forming core mold (4) is heated to expand and extrude the fiber composite material layer towards the secondary rigid outer mold, and meanwhile, the fiber composite material layer is solidified and shaped. According to the forming method, the local protruding structure can be formed on the workpiece body, the workpiece body is kept complete, and the forming method has high production efficiency and good overall performance and is suitable for preparing the telescopic boom.

Description

Technical Field

[0001] The present invention relates to fiber composite parts, and particularly to a method for forming a locally convex structure of a part. On this basis, the present invention further relates to a production method of a fiber composite part and a fiber composite part manufactured by using the production method. In addition, the present invention further relates to a boom machine having a fiber composite boom manufactured by using the production method. Background Art

[0002] In boom machines such as cranes and aerial work platforms, as an important load-bearing structural member, the performance of the boom greatly affects the overall vehicle technical level and performance. In traditional technologies, booms are usually made of high-strength steel materials. With the development of new materials and production processes, in order to meet the requirements of lightweight development, fiber composite booms have received increasing attention. Fiber composites have been widely studied for their high specific strength and specific modulus, good fatigue resistance, damage safety and damping and vibration reduction effects, as well as excellent designability, and have become the mainstream direction of boom lightweight development.

[0003] According to the action form of the boom, the booms adopted by engineering equipment can be divided into folding booms and telescopic booms. In order to connect adjacent boom sections or components such as oil cylinders, end hinge holes and oil cylinder hinge holes are usually also provided on the boom. Such hinge holes can be formed on an additionally connected metal connecting piece or an integrally prepared locally convex structure.

[0004] For example, Chinese Patent Application CN112127631A discloses a method for manufacturing a boom section, which forms an end elbow and a driving element hinge part on the boom body by installing a hinge point core mold on the boom body core mold and integrally winding fiber composites. However, since a complete part body cannot be formed, this method is only applicable to the manufacture of folding booms and is not applicable to the manufacture of telescopic booms that require a complete part body. For telescopic booms, additional metal connecting pieces can usually be connected to the part body as the hinge basis for adjacent boom sections or boom cylinders. Summary of the Invention

[0005] The object of the present invention is to provide a method suitable for manufacturing locally convex structures on parts such as telescopic booms by using fiber composites, which can keep the obtained part body complete and has high production efficiency and good overall performance.

[0006] To achieve the above object, on the one hand, the present invention provides a method for forming a locally convex structure of a part, including:

[0007] A secondary core mold installation step: fixedly connecting a secondary forming core mold to a predetermined position of the part body and covering one surface of the part body at the predetermined position;

[0008] Fiber winding step: spirally winding the fiber yarn impregnated with resin onto the outer surface of the secondary molding core mold and the remaining side surfaces of the workpiece body corresponding to the position of the secondary molding core mold to form a fiber composite layer;

[0009] Secondary rigid outer mold installation and heating and curing step: installing the secondary rigid outer mold to surround the fiber composite layer, heating the fiber composite layer, and expanding the secondary molding core mold to press the fiber composite layer toward the secondary rigid outer mold, so that the fiber composite layer is cured and shaped and a local protruding structure is formed on the main body of the workpiece.

[0010] Preferably, the molding method further comprises: a surface cleaning step of the component body performed before the secondary core mold installation step, that is, cleaning the outer surface portion of the component body that is in contact with the spirally wound fiber yarn.

[0011] Preferably, the secondary molding core mold includes a secondary rigid core mold layer and a secondary expansion core mold layer coated on the outer surface thereof, wherein the secondary expansion core mold layer can be made of a material with a large thermal expansion coefficient such as silicone rubber, and the secondary core mold installation steps include:

[0012] S11. The secondary rigid core mold layer is fixedly connected to a predetermined position of the main body of the workpiece;

[0013] S12. Installing the secondary expansion core mold layer onto the outer surface of the secondary rigid core mold layer,

[0014] The secondary rigid outer mold installation and heating and curing step includes: heating the secondary expansion core mold layer so that the secondary expansion core mold layer thermally expands and presses the fiber composite layer toward the secondary rigid outer mold.

[0015] Preferably, the molding method further comprises: a demoulding step performed after the secondary rigid outer mold installation and heating and curing step: removing the secondary rigid outer mold and the secondary molding core mold.

[0016] Preferably, the demoulding step comprises:

[0017] S41. Grooving the local raised structure formed by curing and shaping the fiber composite layer;

[0018] S42. Remove the secondary molding core mold from the local protruding structure.

[0019] Preferably, the molding method further comprises: a hinge hole processing step performed after the demoulding step, that is, a hinge hole for connecting a pivot shaft is opened on the local protruding structure.

[0020] Preferably, the fiber yarn includes at least one of carbon fiber, glass fiber and aramid fiber, and the resin includes at least one of epoxy resin, unsaturated resin and phenolic resin.

[0021] Preferably, the fiber winding step comprises:

[0022] S21. spirally winding the fiber yarn onto the outer surface of the secondary molding core mold at a first spiral winding angle; S22. spirally winding the fiber yarn at a second spiral winding angle different from the first spiral winding angle, and / or,

[0023] A metal lining plate is embedded between at least some of the adjacent winding layers of the fiber yarns.

[0024] Preferably, the fiber winding step includes: after spirally winding at least a portion of the fiber yarn, monitoring the actual contour size of the local protruding structure and comparing whether the actual contour size is consistent with the designed contour size, and if inconsistent, adjusting the tension of the subsequently spirally wound fiber yarn and / or compacting the portion of the local protruding structure that protrudes relative to the designed contour size.

[0025] Preferably, in the fiber winding step, the actual contour size of the local protruding structure is monitored by manual measuring tools or laser scanning, and / or, the tension of the subsequently spirally wound fiber yarn is adjusted by an electronic tension system of a winding machine used to wind the fiber yarn, and / or, a pressing plate or a roller is used to compact the portion of the local protruding structure that protrudes relative to the designed contour size.

[0026] Preferably, the fiber winding step further comprises: spirally winding circumferential fibers outside the winding layer of the fiber yarn, wherein the spiral winding angle of the circumferential fibers relative to the length direction of the component body is not less than 80°.

[0027] Preferably, before the helical winding of the hoop fiber, the actual contour size of the local protrusion structure is monitored and compared with the designed contour size,

[0028] If the actual outline size is larger than the designed outline size, the annular fiber is spirally wound in a manner that adjacent spirals are spaced apart;

[0029] If the actual outline size is smaller than the designed outline size, the annular fiber is spirally wound in a manner where adjacent spirals are adjacent to each other or overlapped.

[0030] Preferably, in the secondary rigid outer mold installation and heating and curing step, the fiber composite layer is heated by at least one of curing furnace heating, microwave heating and self-resistance heating.

[0031] The second aspect of the present invention provides a production method for a fiber composite part, including:

[0032] Forming step of the part main body: preparing the part main body;

[0033] Using the forming method of the local convex structure of the above part to form a local convex structure on the part main body.

[0034] Preferably, the forming step of the part main body includes:

[0035] Spiral fiber winding step S10 of the part main body: spirally winding the fiber yarn infiltrated with resin onto the outer peripheral surface of the expandable core mold of the part main body to form a spiral winding layer, wherein the expandable core mold of the part main body has a primary expandable core mold layer at least partially covering its outer peripheral surface;

[0036] Installation and heating curing step S20 of the primary rigid outer mold: installing the primary rigid outer mold to surround the spiral winding layer, heating the primary expandable core mold layer and / or the spiral winding layer, so that the primary expandable core mold layer thermally expands and extrudes the spiral winding layer towards the primary rigid outer mold, and at the same time making the spiral winding layer cure and take shape to form the part main body.

[0037] Preferably, the forming step of the part main body and the forming method of the local convex structure of the part use the fiber yarn of the same material.

[0038] The third aspect of the present invention provides a fiber composite part made by the above production method.

[0039] The fourth aspect of the present invention provides a boom machine with a fiber composite boom, and the fiber composite boom is made by the above production method.

[0040] Through the above technical solutions, the forming method of the present invention uses the secondary forming core mold connected to the part main body as the winding basis of the fiber yarn, so that the part main body can be kept intact after demolding and can be used to form the local convex structure of the telescopic boom. Among them, the fiber is continuously laid by the spiral winding method, which can effectively improve the production efficiency and make the fiber continuous, ensuring the mechanical properties of the local convex structure. And during the curing and forming process, by making the secondary forming core mold expand to apply pressure to the fiber composite layer, expansion pressure can be generated in all directions, playing the role of shape maintenance and pressure holding. As a result, the resin distribution in the local convex structure is more uniform, and the local convex structure is accurately shaped by the secondary rigid outer mold. The obtained local convex structure has high dimensional accuracy and good overall performance, meeting the forming requirements of complex structures. Description of the Drawings

[0041] Figure 1It is a perspective view of a workpiece body expansion core mold used in preparing a workpiece body in the production method of a fiber composite workpiece according to a preferred embodiment of the present invention;

[0042] Figure 2 It is Figure 1 a left view of the workpiece body expansion core mold in;

[0043] Figure 3 It is Figure 1 a perspective view of the rigid core shaft and the primary rigid core mold layer of the workpiece body expansion core mold in;

[0044] Figure 4 It is Figure 1 a perspective view of the primary expansion core mold layer of the workpiece body expansion core mold in;

[0045] Figure 5 It is a schematic diagram when installing a primary rigid outer mold onto a workpiece body in the production method of a fiber composite workpiece according to a preferred embodiment of the present invention;

[0046] Figure 6 It is a schematic diagram after the primary rigid outer mold is installed onto the workpiece body;

[0047] Figure 7 It is after the workpiece body is cured and shaped to remove Figure 6 the primary rigid outer mold in;

[0048] Figure 8 It is a fiber composite workpiece to be prepared with a local convex structure;

[0049] Figure 9 It is a schematic diagram when fixedly connecting a secondary rigid core mold layer to a workpiece body;

[0050] Figure 10 It is when installing a secondary expansion core mold layer onto Figure 9 the outer surface of the secondary rigid core mold layer shown in;

[0051] Figure 11 It is Figure 9 an enlarged view of the secondary rigid core mold layer used in;

[0052] Figure 12 It is Figure 10 an enlarged view of the secondary expansion core mold layer used in;

[0053] Figure 13 It is a schematic diagram of helically winding fiber yarns on the outer surface of a secondary forming core mold and the remaining side surfaces of the workpiece body corresponding to the position where the secondary forming core mold is located to form a local convex structure;

[0054] Figure 14It is a schematic diagram showing the pre-embedded metal inner lining plate at the position corresponding to the hinge hole of the local convex structure;

[0055] Figure 15 It is a laminated structure composed of a fiber winding layer and a metal layer at the position corresponding to the hinge hole of the local convex structure;

[0056] Figure 16 It is a schematic diagram showing the compaction of the part protruding from the relative design contour size on the local convex structure formed by helically winding fiber yarns by a roller;

[0057] Figure 17 It is a schematic diagram showing the installation of the secondary rigid outer mold onto the local convex structure during the forming process of the local convex structure of the workpiece;

[0058] Figure 18 It is a schematic diagram after the secondary rigid outer mold is installed onto the local convex structure;

[0059] Figure 19 It is a partial view after removing the secondary forming core mold and other components from the local convex structure and opening a hinge hole thereon;

[0060] Figure 20 It is a flowchart of the production method of the fiber composite boom according to a preferred embodiment of the present invention, which includes the process of the forming method of the local convex structure of the workpiece according to a preferred embodiment of the present invention.

[0061] Explanation of reference numerals

[0062] 1 - workpiece main body expansion core mold; 11 - rigid mandrel; 12 - primary rigid core mold layer; 13 - primary expansion core mold layer; 2 - primary rigid outer mold; 3 - workpiece main body; 4 - secondary forming core mold; 41 - secondary rigid core mold layer; 42 - secondary expansion core mold layer; 5 - secondary rigid outer mold; 8 - roller; 9 - local convex structure; 91 - winding layer; 92 - metal inner lining plate; 93 - hinge hole. Detailed description of the specific implementation mode

[0063] The following is a detailed description of the specific implementation mode of the present invention in conjunction with the accompanying drawings. It should be understood that the specific implementation mode described here is only used to illustrate and explain the present invention, and is not used to limit the present invention.

[0064] Refer to Figures 1 to 20As shown, one aspect of the present invention provides a forming method for a locally convex structure of a workpiece, which is used to form locally convex structures such as end hinge holes and cylinder hinge holes on workpieces such as boom arms, so as to facilitate the connection of adjacent boom sections or components such as boom cylinders. On this basis, another aspect of the present invention further provides a production method for fiber composite workpieces. This production method is used to prepare workpieces such as boom arms for boom machinery such as cranes and aerial work platforms using fiber composites to meet the requirements of lightweight development. Generally, the boom of boom machinery may include a plurality of boom sections that are telescopically connected or pivotally connected to each other, and are driven by a boom cylinder to cause relative telescopic movement or rotation of adjacent boom sections to achieve functions such as lifting and material transportation. It can be understood from the following detailed description that although the forming method and production method of the present invention are described as being used to prepare fiber composite boom arms and the locally convex structures thereon, the boom arms described herein should be understood broadly as the boom sections that make up the complete boom. And although the production method and forming method of the present invention will be mainly described in detail with the boom as the preparation object below, the production method and forming method can also be used for the production of other workpieces.

[0065] As shown in the figure, the production method of the fiber composite workpiece provided by the present invention includes a workpiece body forming step S100 for preparing the workpiece body 3 (please refer to Figures 7 to 10 ) and a plurality of steps for forming a locally convex structure 9 (please refer to Figure 18 and Figure 19 ) on the workpiece body 3, and finally a workpiece such as a boom section with a locally convex structure 9 as shown in Figure 8 is obtained. Among them, the workpiece body 3 can be made by a variety of suitable methods, such as obtaining a high-precision workpiece body 3 through processes such as hot pressing, pultrusion, or winding. Furthermore, based on the workpiece body 3, the forming method of the locally convex structure of the workpiece provided by the present invention is used to form the locally convex structure 9 on the workpiece body 3. In a preferred embodiment, the workpiece body 3 can be prepared by combining the hot pressing process and the winding process to improve production efficiency and ensure its good overall performance, which will be described in detail later.

[0066] Referring to Figures 9 to 20 , the forming method of the locally convex structure of the workpiece of the present invention includes a secondary core mold installation step S1, a fiber winding step S2, and a secondary rigid outer mold installation and heating curing step S3. In the secondary core mold installation step S1, as shown in Figures 9 to 12As shown, the secondary forming core mold 4 is fixedly connected to a predetermined position of the workpiece body 3 and covers one side surface of the workpiece body 3 at this predetermined position. Among them, the secondary forming core mold 4 may have a secondary expansion core mold layer 42 that at least partially covers its outer surface. In the fiber winding step S2, the fiber yarn impregnated with resin is helically wound around the outer surface of the secondary forming core mold 4 and the remaining side surfaces of the workpiece body 3 corresponding to the position where the secondary forming core mold 4 is located (i.e., the remaining surfaces not covered by the secondary forming core mold 4) to form a fiber composite layer. Thus, the fiber yarn is helically wound to be joined to the surface of the workpiece body 3 at these surface positions. In the secondary rigid outer mold installation and heat curing step S3, as Figure 17 and Figure 18 shown, the secondary rigid outer mold 5 is installed to surround the fiber composite layer, and then the secondary expansion core mold layer 42 and / or the fiber composite layer are heated so that the secondary expansion core mold layer 42 thermally expands and presses the fiber composite layer toward the secondary rigid outer mold 5, while causing the fiber composite layer to be cured and shaped to form a local convex structure 9 on the workpiece body 3.

[0067] The forming method of the present invention uses the connection of the secondary forming core mold 4 on the workpiece body 3 as the winding basis for the fiber yarn. Thus, the integrity of the workpiece body 3 can be maintained after demolding, and it can be used to form the local convex structure 9 of the telescopic boom. Among them, the continuous laying of fibers by means of helical winding can effectively improve production efficiency and make the fibers continuous, ensuring the mechanical properties of the local convex structure 9. And during the curing and forming process, by causing the secondary forming core mold to expand (especially by the thermal expansion of the secondary expansion core mold layer 42) and applying pressure to the fiber composite layer, expansion pressure can be generated in all directions, playing the role of shape maintenance and pressure holding. Thus, the resin distribution in the local convex structure 9 is more uniform, and it is precisely shaped by the secondary rigid outer mold 5. The obtained local convex structure 9 has high dimensional accuracy and good overall performance, meeting the forming requirements of complex structures.

[0068] According to the above, the forming method of the present invention basically does not damage the integrity of the workpiece body 3, and the local convex structure 9 is hot-pressed and formed by the secondary expansion core mold layer 42 of the secondary forming core mold 4, which can effectively ensure the fiber density and the uniformity of resin distribution. The formed local convex structure 9 can be effectively connected to the workpiece body 3 and has good mechanical properties, which is beneficial to ensuring dimensional accuracy and is particularly suitable for the preparation of telescopic booms or non-rotating body booms with high requirements for dimensional accuracy, mechanical properties, and structural adaptability. Although the traditional production method can basically meet the performance requirements for folding booms, it does not exclude the use of the production method and forming method of the present invention for the preparation of folding booms.

[0069] To facilitate a better understanding of the forming method and production method provided by the present invention, the following is in accordance with Figure 20The process flow shown illustrates each step of the preferred embodiment and the devices / equipment used, etc.:

[0070] S100. Forming Step of the Part Main Body

[0071] This step is used to prepare the main body 3 of the workpiece. In a preferred embodiment, the forming step S100 of the main body of the workpiece may include the spiral fiber winding step S10 of the main body of the workpiece and the primary rigid outer mold installation and heating curing step S20, etc. In the spiral fiber winding step S10 of the main body of the workpiece, the fiber yarn impregnated with resin is spirally wound around the outer peripheral surface of the expandable core mold 1 of the main body of the workpiece to form a spiral fiber layer. Among them, the expandable core mold 1 of the main body of the workpiece may have a primary expandable core mold layer 13 that at least partially covers its outer peripheral surface. In the primary rigid outer mold installation and heating curing step S20, the primary rigid outer mold 2 is installed to surround the spiral fiber layer (as Figure 5 and Figure 6 shown), and then the primary expandable core mold layer 13 and / or the spiral fiber layer are heated so that the primary expandable core mold layer 13 thermally expands and presses the spiral fiber layer toward the primary rigid outer mold 2, while causing the spiral fiber layer to be cured and shaped.

[0072] This forming step uses the expandable core mold 1 of the main body of the workpiece with the primary expandable core mold layer 13 as the winding basis for the fiber yarn, and continuously lays fibers on the expandable core mold 1 of the main body of the workpiece by means of spiral winding (such as through a winding machine), thereby being able to effectively improve the production efficiency of workpieces such as fiber composite boom arms, and making the fibers continuous, ensuring the mechanical properties of the main body 3 of the workpiece. Moreover, during the curing and forming process, by causing the primary expandable core mold layer 13 to thermally expand and apply pressure to the spiral fiber layer, an expansion pressure applied to the spiral fiber layer can be generated in all directions, playing a role in maintaining the shape and pressure, thereby making the resin distribution of the whole workpiece more uniform, the inner surface quality higher, and being precisely shaped by the primary rigid outer mold 2. The obtained main body 3 of the workpiece has high dimensional accuracy and good overall performance. Among them, by using the expandable core mold 1 of the main body of the workpiece with the primary expandable core mold layer 13 to thermally press and form the spiral fiber layer, the fiber density and resin distribution uniformity can be effectively ensured. The obtained main body 3 of the workpiece has high inner surface quality and good mechanical properties, which is beneficial to ensuring the dimensional accuracy of the workpiece and is particularly suitable for the preparation of telescopic boom arms or non-rotating body boom arms with high requirements for dimensional accuracy, mechanical properties, and structural adaptability.

[0073] Figures 1 to 4Shown is the main body expansion core mold 1 of the workpiece that can be used in the spiral fiber winding step S10 of the above-mentioned workpiece main body, and its components such as the primary expansion core mold layer 13. Among them, the main body expansion core mold 1 of the workpiece can have a rigid mandrel 11, a primary rigid core mold layer 12, and a primary expansion core mold layer 13. The rigid mandrel 11 and the primary rigid core mold layer 12 can be made of metal materials and can be connected to the rotary drive device through the rigid mandrel 11 so as to be driven to rotate around its central axis, so that the fiber yarn to be helically wound and the circumferential fiber will be helically wound on the outer peripheral surface of the main body expansion core mold 1 of the workpiece respectively in the spiral fiber winding step S10 and the circumferential fiber winding step detailed below. The primary expansion core mold layer 13 can be made of a material with a relatively large coefficient of thermal expansion such as silicone rubber and is coated and fixed on the outer periphery of the primary rigid core mold layer 12. For non-rotating boom, after the fiber yarn is wound around the main body expansion core mold 1 of the workpiece, the tension and resin content at the corner position of the corresponding boom are different from those at the corresponding other positions (plane part), which will result in the defect that the corner position of the boom is thinner and the plane part is thicker after curing and forming, further affecting the overall mechanical properties of the boom and even not meeting the dimensional accuracy requirements of the telescopic boom. In this regard, the main body expansion core mold 1 of the workpiece can be set such that the thickness of its primary expansion core mold layer 13 at the corner position corresponding to the primary rigid outer mold 2 is less than the thickness of the remaining part, so that the expansion core mold layer 13 has a relatively smaller expansion amount at the corner position compared to the remaining part during hot pressing and forming, which is beneficial to forming a boom with uniform wall thickness and ensuring that the overall boom has high mechanical properties and dimensional accuracy.

[0074] After the preparation and assembly of the main body expansion core mold of the workpiece are completed, a release agent can be coated on the outer surface of the main body expansion core mold 1 (especially the outer surface of the primary expansion core mold layer 13) to facilitate the separation of the main body expansion core mold 1 of the workpiece from the obtained workpiece main body after the workpiece main body is cured and formed, and complete the demolding.

[0075] Furthermore, in the spiral fiber winding step S10 of the workpiece main body, the fiber yarn can be helically wound onto the outer surface of the main body expansion core mold 1 of the workpiece at different spiral winding angles. The fiber composite material can select various suitable types of fiber materials and resin components. For example, the fiber material can be selected as carbon fiber, glass fiber, or aramid fiber, etc., preferably carbon fiber; the resin can be epoxy resin, unsaturated resin, or phenolic resin, etc., preferably epoxy resin. The fiber yarn can be released by a winding machine and helically wound onto the outer surface of the main body expansion core mold 1 at an appropriate tension after being infiltrated with resin in a glue tank to form a spiral fiber layer, or the fiber composite material that is helically wound can directly use fiber prepreg. Among them, the fiber yarn being infiltrated with resin in the glue tank before being wound can not only ensure good interlaminar shear performance but also be beneficial to ensuring that the workpiece size meets the design requirements by dynamically regulating the fiber winding tension and fiber compaction degree subsequently.

[0076] In the process of winding to form a spiral fiber layer, the actual outline size of the workpiece body can also be monitored in real time, and then adjusted according to the difference between the actual outline size and the design outline size of the corresponding stage to ensure the molding accuracy of the workpiece. Specifically, after a portion of the fiber yarn is spirally wound, the actual outline size of the workpiece body can be monitored by manual measuring tools or laser scanning. If the actual outline size is inconsistent with the design outline size of the corresponding stage, the tension of the subsequent spirally wound fiber yarn and / or the protruding portion of the workpiece body relative to the design outline size can be adjusted in time to dynamically adjust the fiber winding tension and fiber compaction. As mentioned above, the fiber yarn can be released by the winding machine (spiral fiber winding machine), and the tension of the subsequent spirally wound fiber yarn can be adjusted by the electronic tension system on the winding machine. For the relatively protruding portion on the plane of the workpiece body, a pressing plate or roller can be used for compaction to squeeze out excess resin. Therefore, during the spiral winding process, if the actual contour size is too small, the fiber tension is reduced, or resin is applied to the corresponding position; if the actual contour size is too large, the fiber tension is increased, or a pressing plate or roller is used to compact the protruding position to squeeze out excess resin. By controlling the resin content of the spiral fiber layer, it is convenient to use a rigid external mold to accurately shape it according to the designed contour size. The above winding, monitoring, tension control and compaction operations are repeated alternately until the spiral fiber layer reaches the designed thickness, and the spiral fiber winding is completed.

[0077] After the spiral fiber winding is completed, the circumferential fiber can also be spirally wound on the outer peripheral surface of the main body of the product, and the spiral winding angle of the circumferential fiber is significantly greater than the winding angle of the above-mentioned spiral fiber, and even close to 90°. Generally, the spiral winding angle of the circumferential fiber is not less than 80°. Thus, the circumferential fiber can wrap the fiber yarn with a relatively small spiral winding angle in the spiral fiber layer, which is conducive to improving the density of the product and facilitating the subsequent installation of a rigid outer mold and heating and curing to maintain the product with good surface quality.

[0078] like Figure 5 and Figure 6As shown, the primary rigid outer mold 2 can include an upper half mold and a lower half mold, and can be connected into one body by fasteners after mold closing. Among them, the primary rigid outer mold 2 can be made of a rigid wave-transparent material, so as to heat the spiral fiber layer by means of microwave heating, infrared heating, etc., and make it cured and formed under the extrusion action of the primary expansion core mold layer 13. Alternatively, the spiral fiber layer can be heated by self-resistance heating. Compared with traditional heating methods such as curing furnace heating, microwave heating, self-resistance heating or composite heating methods are beneficial to the overall uniform heating of the workpiece to ensure the forming quality. In addition, the primary expansion core mold layer 13 undergoes thermal expansion under the action of heat, so as to extrude the spiral fiber layer toward the primary rigid outer mold 2, so that the fibers are densely distributed.

[0079] In the step S20 of installing and heating and curing the primary rigid outer mold, by accurately shaping the outer surface of the workpiece by the primary rigid outer mold 2 and combining the thermal expansion extrusion (profile holding pressure) action of the main body expansion core mold 1 of the workpiece, the obtained workpiece can have high dimensional accuracy and good overall performance, and reduce or avoid the problem of fiber cutting caused by post-treatment such as grinding.

[0080] After the main body 3 of the workpiece is cured and shaped, the primary rigid outer mold 2 can be removed, and the main body expansion core mold 1 of the workpiece can be retained (as Figure 7 shown), so as to be subsequently connected to the rotary drive device through the main body expansion core mold 1 of the workpiece, so as to be driven to rotate around its central axis, so as to wind a local convex structure 9 on the main body 3 of the workpiece.

[0081] The above-mentioned main body forming step S100 of the workpiece combines the advantages of the hot pressing process and the winding process, applies the main body expansion core mold and the primary rigid outer mold to the winding process, the main body expansion core mold has profile holding pressure, circumferential fiber self-locking, and the primary rigid outer mold has accurate shaping. The main body of the workpiece has the advantages of high dimensional accuracy and dense fibers in the hot pressing process, improves production efficiency, reduces costs, and has continuous fiber laying, improving the overall mechanical properties. For the problem of large dimensional fluctuations in the winding process, the present invention proposes to adopt a contour monitoring method combined with a dynamic winding tension and compaction control method to control the resin content of the workpiece, so that the dimensions of the workpiece are always basically consistent with the design dimensions, and then use a rigid outer mold to perform high-precision shaping according to the design dimensions.

[0082] S0. Cleaning Step of the Part Main Body Surface

[0083] Before installing the secondary forming core mold, the outer surface of the main body 3 of the workpiece can be cleaned, especially the outer surface part that is in contact with the fiber yarn to be helically wound subsequently should be ensured to be a clean fiber composite layer, so that the secondary winding fiber for forming the local convex structure is tightly joined with the fiber composite layer of the main body of the workpiece.

[0084] S1. Secondary Core Mould Installation Step

[0085] As shown Figures 9 to 12 in FIG. 3, the secondary forming core mold 4 may include a secondary rigid core mold layer 41 and a secondary expansion core mold layer 42 coated on its outer surface. Among them, the secondary rigid core mold layer 41 may be made of a metal material and is fixedly connected to a predetermined position of the workpiece body 3 (i.e., sub-step S11) by means of fasteners or adhesives during the secondary core mold installation step S1, so as to fix and support the secondary expansion core mold layer 42.

[0086] According to different design and manufacturing requirements, a secondary expansion core mold layer 42 of an appropriate material can be selected and made to have an appropriate thickness. The secondary expansion core mold layer 42 may be made of a material with a relatively large coefficient of thermal expansion such as silicone rubber and is coated and fixed on the outer surface of the secondary rigid core mold layer 41 (i.e., sub-step S12), so as to expand when heated during subsequent heat curing and provide expansion pressure to reduce defects in the fiber composite layer. For the fiber composite layer that is intended to form a local convex structure, it may have different thicknesses, and the secondary expansion core mold layer 42 can be correspondingly set to have different thicknesses so as to be able to provide the shaping pressure required for helical fiber winding and hot pressing.

[0087] The outer contour of the secondary forming core mold 4 is designed to be adapted to match one side surface of the workpiece body 3, so as to be stably fixedly connected to the workpiece body 3 and cover one side surface thereof. At the same time, the secondary forming core mold 4 should be shaped like the local convex structure 9 to be formed, so as to facilitate the formation of a local convex structure 9 of an appropriate shape by winding fiber yarns.

[0088] S2. Fiber Winding Step

[0089] As shown Figure 13 in FIG. 4, in the fiber winding step S2, it is necessary to helically wind the fiber yarn impregnated with resin onto the outer surface of the secondary forming core mold 4 and the remaining side surfaces of the workpiece body 3 corresponding to the position where the secondary forming core mold 4 is located, so as to form the contour of the local convex structure 9 (collectively referred to as the fiber composite layer) and connect to the workpiece body 3 at the remaining side surfaces not covered by the secondary forming core mold 4. Among them, the fiber yarn can be helically wound at different helical winding angles. For example, in sub-step S21, the fiber yarn is helically wound onto the outer surface of the secondary forming core mold 4 at a first helical winding angle; in sub-step S22, the fiber yarn is helically wound at a second helical winding angle different from the first helical winding angle. The first helical winding angle can be, for example, 45°-90°, preferably 45°-60°; the second helical winding angle can be, for example, 30°-45°. The helical winding angle described here refers to the angle between the extending direction of the fiber yarn and the length direction of the workpiece body 3. Winding the fiber yarn at different helical winding angles can help the formed local convex structure 9 withstand loads in different directions and improve its mechanical properties.

[0090] The fiber composite used here can be of the same material as the fiber composite forming the main body 3 of the workpiece, such as the fiber material can be selected from carbon fiber, glass fiber or aramid fiber, etc., preferably carbon fiber; the resin can be epoxy resin, unsaturated resin or phenolic resin, etc., preferably epoxy resin. The fiber yarn can be released by the winding machine, and after being impregnated with resin in the glue tank, it is spirally wound with appropriate tension, or the spirally wound fiber composite can directly use fiber prepreg. Among them, the fiber yarn is impregnated with resin in the glue tank before being wound, which can not only ensure good interlayer shear performance, but also facilitates the subsequent dynamic regulation of the fiber winding tension and fiber compaction to ensure that the size of the local protrusion structure meets the design requirements.

[0091] In order to improve the connection strength and bearing capacity between the local protrusion structure 9 and other components (such as the boom cylinder), a metal lining plate 92 can be embedded between at least part of the adjacent winding layers 91 of the fiber yarn. Figure 14 and Figure 15 The metal lining plate 92 can be arranged at a position connected with other components, such as the position of the hinge hole 93 described later (see Figure 19 ) to reduce the size of the metal lining plate 92 as much as possible and reduce its adverse effect on lightweighting.

[0092] In the fiber winding step S2, the actual outline size of the local protruding structure 9 can also be monitored in real time, and then adjusted according to the difference between the actual outline size and the design outline size of the corresponding stage to ensure the molding accuracy. Specifically, after a portion of the fiber yarn is spirally wound, the actual outline size of the local protruding structure 9 can be monitored by manual measuring tools or laser scanning. If the actual outline size is inconsistent with the design outline size of the corresponding stage, the tension of the subsequent spirally wound fiber yarn and / or the protruding portion of the local protruding structure 9 relative to the design outline size can be adjusted in time to dynamically adjust the fiber winding tension and fiber compaction. As mentioned above, the fiber yarn can be released by the winding machine (spiral fiber winding machine), and the tension of the subsequent spirally wound fiber yarn can be adjusted by the electronic tension system on the winding machine. For the relatively protruding portion, a pressing plate or roller can be used for compaction to squeeze out excess resin. Figure 16 The schematic diagram shows the operation of using the roller 8 to compact the portion of the local protruding structure 9 that is protruding relative to the designed contour size.

[0093] Thus, during the spiral winding process, if the actual contour size is on the small side, the fiber tension is adjusted downward, or resin is applied at the corresponding position; if the actual contour size is on the large side, the fiber tension is adjusted upward, or a pressing plate or roller is used to compact the protruding position to squeeze out the excess resin. By controlling the resin content in the local convex structure 9, it is convenient to accurately shape the subsequent secondary rigid outer mold according to the designed contour size.

[0094] The above-mentioned winding, monitoring, tension regulation, and compaction operations are alternately repeated until the fiber winding layer reaches the predetermined thickness. Thus, the spiral fiber winding is completed.

[0095] Before installing the secondary rigid outer mold, circumferential fibers can also be spirally wound outside the winding layer 91 of the fiber yarn. The spiral winding angle of the circumferential fibers is significantly larger than that of the above-mentioned spiral fibers, and even close to 90°. Generally, the spiral winding angle of the circumferential fibers is not less than 80°. Thus, the circumferential fibers can wrap the fiber yarn with a relatively small spiral winding angle inside, which is beneficial to improving the fiber density and facilitating maintaining good surface quality of the local convex structure 9 during the subsequent installation of the secondary rigid outer mold and heating and curing.

[0096] The tension and coverage of the circumferential fibers during spiral winding can be determined according to the difference between the actual contour size and the designed contour size of the fiber winding layer. If the actual contour size is on the large side, the circumferential fibers are spirally wound in an adjacent spiral spaced manner, and the winding tension of the circumferential fibers can be set relatively large, which is beneficial to squeezing out the excess resin; if the actual contour size is on the small side, the circumferential fibers are spirally wound in an adjacent spiral adjacent or overlapping manner, and the winding tension of the circumferential fibers can be set relatively small. Similar to the winding method of the above-mentioned spiral fiber layer, the circumferential fibers can be wound on the outer peripheral surface of the workpiece body by a circumferential fiber winding machine. As a preferred embodiment, the circumferential fibers can also be released and wound on the outer peripheral surface of the workpiece body by the above-mentioned spiral fiber winding machine, thus saving equipment costs and improving production efficiency when manufacturing large-sized boom arms.

[0097] S3. Installation and Heating Curing Step of the Secondary Rigid Outer Mould

[0098] Such as Figure 17 and Figure 18As shown, the secondary rigid outer mold 5 can also include an upper half mold and a lower half mold, and can be connected into one body by fasteners after mold closing. Among them, the secondary rigid outer mold 5 can be made of a rigid wave-transparent material, so as to heat the fiber composite layer by means of microwave heating, infrared heating, etc., and make it cured and formed under the extrusion action of the secondary expansion core mold layer 42. Alternatively, the fiber composite layer can be heated by self-resistance heating. Compared with traditional heating methods such as curing furnace heating, microwave heating, self-resistance heating or composite heating methods are beneficial to uniform overall heating to ensure the forming quality. In addition, the secondary expansion core mold layer 42 undergoes thermal expansion under the action of heat, so as to extrude the fiber winding layer towards the secondary rigid outer mold 5, so that the fibers are densely distributed.

[0099] By precisely shaping the outer surface of the local convex structure 9 with the secondary rigid outer mold 5 and combining the thermal expansion extrusion (profile holding pressure) action of the secondary forming core mold 4, the obtained local convex structure 9 can have high dimensional accuracy and good overall performance, and reduce or avoid fiber cutting problems caused by post-treatment such as grinding.

[0100] S4. Demoulding Step

[0101] After the local convex structure 9 is cured and shaped, the secondary rigid outer mold 5 and the secondary forming core mold 4 can be removed to complete demolding. Among them, since the secondary forming core mold 4 is covered by the fiber winding layer (as Figure 13 shown), therefore, to take out the secondary forming core mold 4, it is necessary to slot the local convex structure 9, that is, perform the following sub-steps: S41. Slot the local convex structure 9 formed by curing and shaping the fiber composite layer; S42. Take out the secondary forming core mold 4 from the local convex structure 9.

[0102] S5. Hinge Hole Machining Step

[0103] Finally, hinge holes 93 for connecting the pivot shaft are opened at appropriate positions on the local convex structure 9, and finally, as Figure 8 and Figure 19 shown, the local convex structure 9 is formed on the workpiece body 3. The workpiece has good inner and outer surface qualities and high dimensional accuracy, and is suitable for use as a telescopic boom.

[0104] The forming method and production method of the present invention combine the advantages of the hot pressing process and the winding process, apply the expandable core mold and the rigid outer mold to the winding process, maintain pressure for the expandable core mold in its prototype, achieve circumferential fiber self-locking, and the rigid outer mold precisely shapes the part. The main body of the part and the local convex structure thereon have the advantages of high dimensional accuracy and dense fibers in the hot pressing process, improve production efficiency, reduce costs, and the fibers are continuously laid, improving the overall mechanical properties. For the problem of large dimensional fluctuations in the winding process, the present invention proposes to use contour monitoring in combination with dynamic winding tension and compaction control methods to control the resin content, so that the forming dimensions are always basically consistent with the design dimensions, and then use the rigid outer mold to perform high-precision shaping according to the design dimensions.

[0105] Furthermore, the present invention also provides a fiber composite part and a boom machine with a fiber composite boom, such as a crane. Among them, the fiber composite part and the fiber composite boom are made by the above production method.

[0106] The preferred embodiments of the present invention have been described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention. For example, the expandable core mold 1 of the part main body and the secondary forming core mold 4 can also be expanded and extrude the helical winding layer (fiber composite layer) in other ways. For example, it can be made of a material that can be vacuum compressed, and is deformed by wrapping it in a pressure bag and sucking out the air therein to serve as the winding basis for the fibers, and gas is introduced into the pressure bag during heating and curing to make it expand, so as to apply pressure to the fiber layer. In addition, the simple modifications also include the combination of each specific technical feature in any suitable way. To avoid unnecessary repetition, the present invention does not explain various possible combination methods separately. But these simple modifications and combinations should also be regarded as the content disclosed by the present invention and all fall within the protection scope of the present invention.

Claims

1. A method for forming a local protruding structure of a workpiece, characterized in that: include: Secondary core mold installation step (S1): fixing the secondary molding core mold (4) to a predetermined position of the component body (3), and covering one side surface of the component body (3) at the predetermined position; Fiber winding step (S2): spirally winding the fiber yarn impregnated with resin onto the outer surface of the secondary molding core mold (4) and the remaining side surfaces of the workpiece body (3) corresponding to the position of the secondary molding core mold (4) to form a fiber composite layer; Secondary rigid outer mold installation and heating and curing step (S3): installing the secondary rigid outer mold (5) to surround the fiber composite layer, heating the fiber composite layer, and allowing the secondary molding core mold (4) to expand and press the fiber composite layer toward the secondary rigid outer mold (5), so that the fiber composite layer is cured and shaped and a local protruding structure (9) is formed on the workpiece body (3).

2. The method for forming a local protruding structure of a workpiece according to claim 1, characterized in that: Also includes: The part body surface cleaning step (S0) performed before the secondary core mold installation step (S1) is to clean the outer surface portion of the part body (3) that is in contact with the spirally wound fiber yarn.

3. The method for forming a local protruding structure of a workpiece according to claim 1, characterized in that: The secondary molding core mold (4) comprises a secondary rigid core mold layer (41) and a secondary expansion core mold layer (42) coated on the outer surface thereof, and the secondary core mold installation step (S1) comprises: S11. The secondary rigid core mold layer (41) is fixedly connected to a predetermined position of the workpiece body (3); S12. Installing the secondary expansion core mold layer (42) onto the outer surface of the secondary rigid core mold layer (41), The secondary rigid outer mold installation and heating and curing step (S3) comprises: heating the secondary expansion core mold layer (42) so that the secondary expansion core mold layer (42) thermally expands and presses the fiber composite layer toward the secondary rigid outer mold (5).

4. The method for forming a local protruding structure of a workpiece according to claim 1, characterized in that: Also includes: A demoulding step (S4) is performed after the secondary rigid outer mold installation and heating and curing step (S3): removing the secondary rigid outer mold (5) and the secondary molding core mold (4).

5. The method for forming a local protruding structure of a workpiece according to claim 4, characterized in that: The demoulding step (S4) comprises: S41. Grooving the local raised structure (9) formed by curing and shaping the fiber composite layer; S42. Remove the secondary molding core mold (4) from the local protruding structure (9).

6. The method for forming a local protruding structure of a workpiece according to claim 4, characterized in that: Also includes: A hinge hole processing step (S5) is performed after the demoulding step (S4): a hinge hole (93) for connecting a pivot shaft is opened on the local protruding structure (9).

7. The method for forming a local protruding structure of a workpiece according to claim 1, characterized in that: The fiber yarn includes at least one of carbon fiber, glass fiber and aramid fiber, and the resin includes at least one of epoxy resin, unsaturated resin and phenolic resin.

8. The method for forming a local protruding structure of a workpiece according to any one of claims 1 to 7, characterized in that: The fiber winding step (S2) comprises: S21. spirally winding the fiber yarn onto the outer surface of the secondary molding core mold (4) at a first spiral winding angle; S22. spirally winding the fiber yarn at a second spiral winding angle different from the first spiral winding angle, and / or, A metal lining plate (92) is embedded between at least a portion of adjacent winding layers (91) of the fiber yarn.

9. The method for forming a local protruding structure of a workpiece according to any one of claims 1 to 7, characterized in that: The fiber winding step (S2) includes: after spirally winding at least a portion of the fiber yarn, monitoring the actual contour size of the local protruding structure (9) and comparing the actual contour size with the designed contour size to see if they are consistent, and if they are inconsistent, adjusting the tension of the subsequent spirally wound fiber yarn and / or compacting the portion of the local protruding structure (9) that protrudes relative to the designed contour size.

10. The method for forming a local protruding structure of a workpiece according to claim 9, characterized in that: In the fiber winding step (S2), the actual contour size of the local raised structure (9) is monitored by manual measuring tools or laser scanning, and / or the tension of the subsequently spirally wound fiber yarn is adjusted by an electronic tension system of a winding machine used to wind the fiber yarn, and / or a pressing plate or roller (8) is used to compact the portion of the local raised structure (9) that protrudes relative to the designed contour size.

11. The method for forming a local protruding structure of a workpiece according to any one of claims 1 to 7, characterized in that: The fiber winding step (S2) further comprises: Hoop fibers are spirally wound outside the winding layer (91) of the fiber yarn, and the spiral winding angle of the hoop fibers relative to the length direction of the component body (3) is not less than 80 degrees.

12. The method for forming a local protruding structure of a workpiece according to claim 11, characterized in that: Before spirally winding the hoop fiber, the actual outline size of the local protrusion structure (9) is monitored and compared with the designed outline size, If the actual outline size is larger than the designed outline size, the annular fiber is spirally wound in a manner that adjacent spirals are spaced apart; If the actual outline size is smaller than the designed outline size, the annular fiber is spirally wound in a manner where adjacent spirals are adjacent to each other or overlapped.

13. The method for forming a local protruding structure of a workpiece according to any one of claims 1 to 7, characterized in that: In the secondary rigid outer mold installation and heating and curing step (S3), the fiber composite layer is heated by at least one of curing furnace heating, microwave heating and self-resistance heating.

14. A method for producing a fiber composite material product, characterized in that: include: Part body forming step (S100): preparing a part body (3); A local protruding structure (9) is formed on the part body (3) by using the molding method for a local protruding structure of a part according to any one of claims 1 to 13.

15. The method for producing a fiber composite material product according to claim 14, characterized in that: The step of forming the main body of the product (S100) comprises: Part body spiral fiber winding step S10: spirally winding fiber yarn impregnated with resin onto the outer peripheral surface of the part body expansion core mold (1) to form a spiral winding layer, wherein the part body expansion core mold (1) has a primary expansion core mold layer (13) at least partially covering its outer peripheral surface; A primary rigid outer mold installation and heating and curing step S20: installing the primary rigid outer mold (2) to surround the spiral winding layer, heating the primary expansion core mold layer (13) and / or the fiber composite layer, so that the primary expansion core mold layer (13) thermally expands and presses the spiral winding layer toward the primary rigid outer mold (2), and at the same time, the spiral winding layer is cured and shaped to form the workpiece body (3).

16. The method for producing a fiber composite material product according to claim 15, characterized in that: The step of molding the main body of the component (S100) and the method of molding the local protruding structure of the component use the fiber yarn of the same material.

17. A fiber composite material product, characterized in that: The fiber composite material product is manufactured by the production method according to any one of claims 14 to 16.

18. A boom machine, characterized in that: The boom machine has a fiber composite boom, which is manufactured by the production method according to any one of claims 14 to 16.

Images