Injection molded bicycle component with built-in composite core

Abstract

The utility model discloses a kind of injection molding bicycle components of built-in composite material core, solve the problem of poor reliability of metal piece and composite material main body combination in prior art.The component includes: one by preformed high modulus composite material constitutes internal core layer;At least two metal connecting pieces fixed in internal core layer in advance;And one by thermoplastic plastic through injection molding constitutes external plastic-coated layer.External plastic-coated layer covers internal core layer and partially covers each metal connecting piece, so that the mounting portion of each metal connecting piece is exposed.The utility model realizes high-strength connection by mechanical pre-fixing and injection coating combination, and the structure is reliable and the production efficiency is high.

Description

Technical Field

[0001] This utility model relates to the field of bicycle component technology, specifically to a lightweight, high-strength component that combines an internal composite material core with an external injection-molded coating, and a bicycle crank using this component. Background Technology

[0002] To achieve both lightweight and high strength, high-end bicycle components (such as cranks) are commonly made of carbon fiber composites. However, carbon fiber composites are not suitable for directly machining high-strength, wear-resistant threads, so metal connectors (usually aluminum alloy nuts) must be used at the locations where they connect to other components such as the bicycle bottom bracket and pedals.

[0003] Currently, there are two main existing technologies for combining metal connectors with carbon fiber bodies:

[0004] 1. The metal connectors are pre-placed in the mold, followed by carbon fiber layup and curing. The drawback of this method is the significant difference in thermal expansion coefficients between the metal and carbon fiber composites. During the high temperatures of curing and subsequent cooling, substantial internal stresses are generated between the two, potentially leading to microcracks or delamination at the bonding interface, affecting the strength and durability of the final product.

[0005] 2. First, a carbon fiber body is manufactured, with cavities pre-drilled in it. Then, metal connectors are bonded to these cavities using structural adhesive. While this method avoids thermal stress issues, the properties of the adhesive itself (such as fatigue resistance, high and low temperature resistance, and resistance to damp heat aging) directly determine the reliability of the connection. In components like crankshafts that withstand enormous alternating stresses, the adhesive layer may become a weak point in the entire structure, posing a risk of delamination after long-term use.

[0006] Therefore, how to achieve a more stable and reliable bond between metal connectors and carbon fiber bodies while ensuring lightweight design, and how to simplify the production process, are technical problems that urgently need to be solved in this field. Utility Model Content

[0007] The purpose of this invention is to overcome the problems mentioned in the background art, such as insufficient bonding force between composite materials and metal parts, poor reliability, and complex processes, and to provide an injection-molded bicycle component with a built-in composite material core that is structurally stable, highly efficient in production, and combines lightweight and high strength.

[0008] To achieve the above objectives, the present invention provides an injection-molded bicycle component with an embedded composite material core, characterized in that it comprises:

[0009] An internal core layer, which serves as the main load-bearing framework, is composed of pre-formed high-modulus composite material;

[0010] At least two metal connectors are fixed to preset positions in the inner core layer, respectively;

[0011] An outer plastic coating, made of thermoplastic plastic by injection molding, covers the inner core layer and partially covers each metal connector, so that the mounting parts on each metal connector for connection with other bicycle components are exposed.

[0012] Preferably, the bicycle component is a bicycle crank.

[0013] Preferably, the high-modulus composite material is a thermosetting resin-based carbon fiber composite material.

[0014] Preferably, the resin matrix of the inner core layer is epoxy resin.

[0015] Preferably, the high-modulus composite material is a high-modulus thermoplastic carbon fiber composite material.

[0016] Preferably, the thermoplastic is a carbon fiber reinforced thermoplastic.

[0017] Preferably, the inner core layer is a plate-shaped or hollow shell structure.

[0018] Preferably, the inner core layer is a hollow shell structure with openings at both ends, and there are two metal connectors, each with a connecting part, which are respectively inserted into the openings at both ends of the inner core layer.

[0019] Preferably, the metal connector is fixed to the openings at both ends of the inner core layer by an interference fit.

[0020] Preferably, all metal connectors are made of aluminum alloy.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. This utility model first mechanically pre-fixes the metal connectors to the inner core layer, which serves as the load-bearing skeleton, forming a stable internal component. Subsequently, the outer plastic coating layer is injection molded to further encapsulate and lock the internal component. This "mechanical pre-fixation + injection molding full encapsulation" structure has higher bonding strength and fatigue resistance than simple bonding or integral molding.

[0023] 2. The inner core layer uses a pre-formed high-modulus composite material as the main load-bearing skeleton, ensuring the core rigidity and strength of the component. The outer plastic coating layer uses thermoplastic suitable for injection molding, providing auxiliary rigidity to the component while providing the final complex aerodynamic shape and protecting the internal structure. This "skeleton-skin" separation design achieves optimal configuration of material properties.

[0024] 3. The final shape is formed in one step through injection molding, resulting in a fast production cycle and suitability for large-scale industrial production. At the same time, injection molding also provides a high degree of design freedom for achieving complex curved surfaces and aerodynamic shapes. Attached Figure Description

[0025] Figure 1 This is a three-dimensional structural schematic diagram of an embodiment of the present invention (bicycle crank);

[0026] Figure 2 yes Figure 1 Exploded perspective view of the embodiment shown;

[0027] Figure 3 It is along Figure 1 A sectional view obtained by the center section cut line;

[0028] Figure 4 This is a schematic diagram of the internal core layer in an embodiment of this utility model;

[0029] Figure 5 This is a structural schematic diagram of a metal connector in an embodiment of this utility model;

[0030] Figure 6 This is a schematic diagram of the structure of another metal connector in an embodiment of this utility model.

[0031] Explanation of reference numerals in the attached drawings: 10, inner core layer; 20, metal connector; 21, mounting part; 22, connecting part; 30, outer plastic coating layer. Detailed Implementation

[0032] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings.

[0033] Please see Figures 1 to 6 This utility model discloses an injection-molded bicycle component with a built-in composite material core. In this embodiment, the component is preferably a bicycle crank. The component has a precise multi-layered composite structure, mainly including an inner core layer 10 as the core skeleton, at least two metal connectors 20 for functional connection, and an outer plastic coating layer 30 that constitutes the final shape.

[0034] Reference Figure 4 The inner core layer 10 is the main load-bearing skeleton of the entire component, and it is composed of a pre-formed high-modulus composite material. In a preferred embodiment, the high-modulus composite material is a thermosetting resin-based carbon fiber composite material. To achieve the optimal stiffness-to-weight ratio, T300 or higher performance grade carbon fiber can be used, and the resin matrix is ​​preferably epoxy resin. As another preferred embodiment, the high-modulus composite material can also be a high-modulus thermoplastic carbon fiber composite material.

[0035] Reference Figure 5 and Figure 6 The metal connector 20 serves to provide a high-strength, wear-resistant, and standardized connection interface. In this embodiment, two metal connectors 20 with different structures are included. For weight reduction, the metal connectors 20 are preferably made of aluminum alloy. Each metal connector 20 has a mounting portion 21 for connecting to other components and a connecting portion 22 for achieving a secure connection with the inner core layer 10. In this embodiment, as... Figure 5 The metal connector shown has a mounting portion 21 for connecting to the bicycle bottom bracket; as shown Figure 6 Another metal connector shown has a mounting part 21 for connecting bicycle pedals.

[0036] Reference Figure 3 and Figure 4 Structurally, the inner core layer 10 is preferably a plate-like or hollow shell structure. More specifically, the inner core layer 10 is a hollow shell structure with openings at both ends, and the connecting portions 22 of the two metal connectors 20 are respectively inserted into the openings at both ends of the inner core layer 10. This pre-fixation is preferably achieved through a high-strength mechanical method, such as by using an interference fit to press the metal connectors 20 into place in a tight fit, forming a strong mechanical connection. This mechanical interlocking structure avoids the thermal mismatch internal stress in traditional processes and is more reliable than simple post-bonding.

[0037] Reference Figure 1 and Figure 3 The outer plastic coating 30 is formed by injection molding and is made of thermoplastic. In a preferred embodiment, the thermoplastic is carbon fiber reinforced thermoplastic to improve overall rigidity. During injection molding, the molten thermoplastic completely covers the inner core layer 10 and partially covers each metal connector 20, forming a tight bond. This coating constitutes the final complex aerodynamic shape, protects the internal structure, and provides secondary locking and stress dispersion for the pre-fixed metal connectors 20. Finally, the mounting part 21 is precisely exposed without affecting its function.

[0038] In summary, this invention organically combines a high-performance thermosetting carbon fiber core layer, reliable metal connectors, and a flexible thermoplastic shell to create a high-performance, high-efficiency composite material component, representing a significant improvement in the field of bicycle parts.

[0039] This specification and accompanying drawings are merely illustrative examples of this application and are intended to cover any and all modifications, variations, combinations, or equivalents within the scope of this application. Clearly, those skilled in the art can make various alterations and modifications to this application without departing from its scope. Therefore, if such modifications and modifications fall within the scope of this application and its equivalents, this application intends to include such modifications and modifications.

Claims

1. An injection moulded bicycle component with a built-in composite core, characterised in that, include: An internal core layer (10) serving as the main load-bearing framework is composed of pre-formed high-modulus composite material; At least two metal connectors (20) are fixed at preset positions on the inner core layer (10); An outer plastic coating layer (30), made of thermoplastic plastic by injection molding, covers the inner core layer (10) and partially covers each metal connector (20) so that the mounting parts (21) on each metal connector (20) for connecting with other bicycle components are exposed.

2. Bicycle component according to claim 1, characterized in that The bicycle component is a bicycle crank.

3. The bicycle component of claim 1, wherein, The high-modulus composite material is a thermosetting resin-based carbon fiber composite material.

4. Bicycle component according to claim 3, characterized in that The resin matrix of the inner core layer (10) is epoxy resin.

5. The bicycle component of claim 1, wherein, The high-modulus composite material is a high-modulus thermoplastic carbon fiber composite material.

6. The bicycle component of claim 1, wherein, The thermoplastic is a carbon fiber reinforced thermoplastic.

7. The bicycle component of claim 1, wherein, The inner core layer (10) is a plate-shaped or hollow shell structure.

8. The bicycle component according to claim 7, characterized in that, The inner core layer (10) is a hollow shell structure with openings at both ends. There are two metal connectors (20), each of which has a connecting part (22). The connecting parts (22) of the two metal connectors (20) are respectively inserted into the openings at both ends of the inner core layer (10).

9. Bicycle component according to claim 8, characterized in that The metal connector (20) is fixed to the openings at both ends of the inner core layer (10) by an interference fit.

10. The bicycle component of claim 1, wherein, All metal connectors (20) are made of aluminum alloy.

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