Bicycle fork reinforcement structure

Abstract

The utility model relates to a bicycle front fork reinforcing structure, which comprises a front fork upper tube, a first fork leg tube and a second fork leg tube arranged at one end of the front fork upper tube, and the first and second fork leg tubes extend downward in parallel, characterized in that a shoulder cover is arranged at the bottom end of the front fork upper tube, the two ends of the shoulder cover respectively form a first butt joint cylinder body and a second butt joint cylinder body, the butt joint cylinder bodies respectively have an insertion hole, a first insertion section of the first fork leg tube and a second insertion section of the second fork leg tube are inserted and embedded in the insertion holes, and each forms an overlapping part, an inner lining pipe is arranged in the first and second fork leg tubes, and at least a part of the inner lining pipe is located in the range of each overlapping part, so that an internal support reinforcing structure is formed in the insertion and overlapping area of the front fork upper tube and the fork leg tube, stress concentration can be effectively dispersed, the bending resistance and shear strength of the whole front fork are improved, and the effects of structural reinforcement, light weight and cost reduction are achieved.

Description

Technical Field

[0001] This utility model relates to a reinforcing structure for a bicycle front fork, and is mainly applied in the field of bicycle technology. Background Technology

[0002] Bicycles are currently the lightest and most convenient mode of transportation, combining exercise, leisure, and fitness. With technological advancements and improved road conditions, bicycle speeds and stability have significantly increased, making structural strength and safety a key focus for manufacturers. Especially under high-speed or off-road riding conditions, the frame and fork must simultaneously withstand ground vibrations, steering torque, and braking reaction forces. Therefore, the strength and stability of the fork structure directly affect the overall safety and handling performance of the bicycle.

[0003] Generally, a bicycle fork typically includes a top tube, and a first fork tube and a second fork tube located at one end of the top tube. The first and second fork tubes extend downwards from the top tube and are generally parallel, allowing the front wheel bearing housing or axle to pass through them. When the wheel is running or braking, the impact forces from the ground and axle are primarily transmitted to the top tube and the frame via these two fork tubes. Therefore, the area where the top tube intersects with the two fork tubes is often the region where the overall structure experiences the most concentrated stress and is most prone to fatigue failure.

[0004] Based on the existing bicycle fork structure design, in order to improve the structural strength of the connection area between the top tube and the two side fork tubes, the industry mostly adopts the following two reinforcement methods.

[0005] One approach is to directly increase the wall thickness of the fork tubes on both sides to enhance the bending and shear resistance of the joint area. However, while this method can improve structural rigidity, it also significantly increases the overall weight of the fork, which goes against the trend of lightweight bicycle design and can easily lead to material waste and processing difficulties, thereby reducing manufacturing efficiency.

[0006] Secondly, to balance local reinforcement and weight control, some technologies employ a thickening-thinning tube process (i.e., localized variable-thickness tube technology) to form the fork tube, reinforcing the joint area by locally thickening it. However, this process requires multiple thickness control operations using special drawing dies, demanding high process precision and incurring high equipment costs. This not only increases manufacturing costs but also reduces mass production yield. Furthermore, stress concentration in the thickness transition zone can affect structural durability, leading to fatigue cracks in the fork after prolonged use.

[0007] In other words, although existing technologies can improve the joint strength by thickening the tube wall or forming a thin tube, there are still problems such as excessive weight, high cost and poor manufacturing efficiency. Therefore, the existing structural design still needs to be improved and further improvements are needed. Utility Model Content

[0008] The technical problem this utility model aims to solve is to provide a reinforcing structure for bicycle forks. By setting an inner liner tube inside the fork leg tube, the inner liner tube forms internal support reinforcement in the overlapping area where the fork top tube and the fork leg tube intersect. This effectively disperses stress concentration in the joint area, significantly improves the overall bending and shear resistance of the fork, and further avoids fatigue cracks or structural deformation caused by long-term loads. The inner liner tube eliminates the need to thicken the entire fork leg tube wall to achieve increased strength, thus meeting the lightweight design requirements of bicycle forks. Secondly, the inner liner tube can be formed using conventional thin-walled tubing, eliminating the need for expensive thinning and thickening processes or special molds, thereby significantly reducing production steps and material waste, and improving manufacturing efficiency and assembly convenience. Thirdly, the reinforcement design allows for adjustment of the inner liner tube bushing thickness and length configuration according to different vehicle models, materials, and load conditions, providing good design flexibility. It is suitable for the manufacturing and improvement of aluminum alloy, carbon fiber, or composite material forks, overcoming the shortcomings of existing technologies.

[0009] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: a bicycle front fork reinforcement structure, comprising a front fork upper tube, a first fork leg tube, and a second fork leg tube; the front fork upper tube has a shoulder cover at its bottom end; the first fork leg tube and the second fork leg tube are respectively disposed on both sides of the bottom end of the front fork upper tube and extend downward in a generally parallel manner; the shoulder cover has a first docking cylinder and a second docking cylinder at both ends, and each docking cylinder has an insertion hole formed inside; the upper ends of the first fork leg tube and the second fork leg tube each form an insertion hole. The segments are respectively inserted into the insertion holes of the first docking cylinder and the second docking cylinder, so that the first fork tube and the second fork tube overlap with the first docking cylinder and the second docking cylinder respectively; and inside the first fork tube and the second fork tube, a first inner liner tube and a second inner liner tube are respectively provided, and at least a portion of the first inner liner tube and the second inner liner tube are located within the overlapping portion, thereby forming an internal support and reinforcement structure in the insertion and overlapping area of ​​the front fork top tube and the first fork tube and the second fork tube.

[0010] Preferably, the upper inner hole of the first fork tube and the second fork tube each has a raised section, and the first inner liner tube and the second inner liner tube are respectively inserted into the inner hole area below the raised section.

[0011] Preferably, the top edges of the insertion holes of the first docking cylinder and the second docking cylinder respectively protrude inward to form a retaining flange, which is used to abut and position the upper ends of the first fork tube and the second fork tube to limit the insertion depth and improve the stability of the connection.

[0012] Preferably, the outer diameter of the first inner liner tube and the second inner liner tube is equal to or slightly larger than the inner diameter below the convex section of the corresponding first fork tube and the second fork tube, so that the first inner liner tube and the second inner liner tube can be pressed tightly inside the first fork tube and the second fork tube to form a tight fit.

[0013] Preferably, the upper outer edge of the first inner liner tube and the second inner liner tube is respectively formed with a knurled section within the overlapping portion to increase the friction and anti-slip effect with the inner wall of the first fork tube and the second fork tube, thereby further improving the overall bonding strength and reinforcing stability.

[0014] Preferably, the lower outer edge of the first inner liner tube and the second inner liner tube are respectively formed with a tapered section to facilitate their insertion and engagement with the first fork tube and the second fork tube.

[0015] The beneficial effects of this invention are as follows: Through the aforementioned technical means, this invention utilizes the first and second inner liner tubes to form a stable and continuous support interface within the overlapping area of ​​the fork top tube and the first and second fork leg tubes. This effectively disperses the stress concentration of external loads in this area, thereby significantly improving the overall bending strength and shear resistance of the fork assembly. Compared to traditional structures that only reinforce by thickening the tube wall or thinning the tube, this invention can improve the fatigue life of the joint area while maintaining lightweight design, preventing cracks or permanent deformation under long-term use, ensuring the stability and durability of the fork structure, greatly improving its practicality, and achieving its economic benefits.

[0016] The present invention will now be described in further detail with reference to the accompanying drawings. Attached Figure Description

[0017] Figure 1 This is a three-dimensional exploded diagram of the bicycle front fork reinforcement structure in this creation.

[0018] Figure 2 This is a three-dimensional schematic diagram of the inner liner tube in the bicycle front fork reinforcement structure of this creation.

[0019] Figure 3 This is a partial three-dimensional cross-sectional view of the bicycle front fork reinforcement structure assembled in this creation.

[0020] Figure 4 This is a side view cross-sectional diagram of the bicycle front fork reinforcement structure after this creation. Detailed Implementation

[0021] The bicycle front fork reinforcement structure in this creation, such as Figure 1 and Figure 2As shown, it comprises a front fork top tube 10, a first fork leg tube 20, a second fork leg tube 30, a first inner liner tube 40, and a second inner liner tube 50. The first and second fork leg tubes (20 and 30) are located on both sides of the bottom end of the front fork top tube 10 and extend downward in a generally parallel manner, so as to jointly span the two ends of a wheel axle of a wheel (not shown in the figure).

[0022] The unique features of this bicycle front fork reinforcement structure are, for example... Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, a shoulder cover 11 is provided at the bottom end of the upper tube 10 of the fork. The shoulder cover 11 has a corresponding docking cylinder 12 at each end, which is defined as a first docking cylinder 121 and a second docking cylinder 122, respectively. The first and second docking cylinders (121, 122) each have an insertion hole 120 extending in the direction of the axis of the first and second fork tubes (20, 30) for one end of the first and second fork tubes (20, 30) to be inserted and overlapped. The top edge of the insertion hole 120 of the first and second docking cylinders (121, 122) each has a retaining flange 125 protruding inward.

[0023] The walls of the first and second prong tubes (20, 30) are approximately the same thickness from top to bottom, and the upper sections of the first and second prong tubes (20, 30) each have a connecting section (21, 31), so that the first and second prong tubes (20, 30) can be inserted into the connecting holes 120 of the first and second mating cylinders (121, 122) of the shoulder cover 11 using the connecting sections (21, 31), so that when the first and second mating cylinders (121, 122) are inserted into the first and second prong tubes (20, 30), an overlapping portion A is formed (e.g., ...). Figure 3 and Figure 4 As shown), and the top ends of the first and second forked tubes (20, 30) can abut against the flange 125 of the insertion hole 120 of the first and second mating cylinders (121, 122). Figure 4 As shown), the upper section of the inner hole of each of the first and second forked tubes (20, 30) is formed with a raised section (22, 32), which is used for a tube plug (not shown in the figure) to be inserted downward from above the shoulder cover 11 to produce a waterproof and dustproof function.

[0024] The outer diameter of the first and second inner lining tubes (40, 50) is equal to or slightly larger than the inner diameter below the convex section (22, 32) of the aforementioned first and second forked tubes (20, 30), so that the first and second inner lining tubes (40, 50) can be tightly pressed against the interior of the first and second forked tubes (20, 30), and at least a portion of the first and second inner lining tubes (40, 50) is located between the insertion section (21, 31) of the first and second forked tubes (20, 30) and the insertion section of the connecting cylinder 12 on both sides of the shoulder cover 11. In the overlapping portion A of the connection hole 120, the upper outer edge of the first and second inner liner tubes (40, 50) is respectively formed with a knurled section (41, 51) within the range of each overlapping portion A, which improves their bonding and anti-slip effect, and further enhances the integrity and structural strength of the first and second inner liner tubes (40, 50). The lower outer edge of the first and second inner liner tubes (40, 50) is respectively formed with a tapered section (42, 52) to facilitate their insertion and fitting with the first and second fork tubes (20, 30). Thus, a bicycle front fork reinforcement structure that is both reinforcing and lightweight and low-cost is constructed.

[0025] Based on the aforementioned structural design, when assembling this work in practice, please refer to... Figure 1 , Figure 3 and Figure 4 As shown, this invention mainly uses a set of first and second inner lining tubes (40, 50) configured inside the first and second forked tubes (20, 30) to form a reinforcing support structure. In actual assembly, the aforementioned first inner lining tube 40 and second inner lining tube 50 are respectively embedded inside the corresponding insertion sections (21, 31) of the first forked tube 20 and the second forked tube 30. The installation position of the inner lining tubes (40, 50) is located below the convex section (22, 32) inside the corresponding insertion section (21, 31), thereby ensuring that the first and second inner lining tubes (40, 50) can fit tightly against the inner walls of the first forked tube 20 and the second forked tube 30, forming an effective internal support structure.

[0026] Subsequently, the insertion sections (21, 31) of the first and second fork tubes (20, 30) equipped with the first and second inner liner tubes (40, 50) are respectively inserted from below the shoulder cap 11 of the fork top tube 10 and inserted into the insertion holes 120 of the first docking cylinder 121 and the second docking cylinder 122 provided on both sides of the shoulder cap 11. After insertion, the first and second docking cylinders (121, 122) on both sides of the fork top tube 10 and the first and second fork tubes (20, 30) on both sides fit together, forming an overlapping portion A in their joint area. A portion of the first and second inner liner tubes (40, 50) also extends into the range of the overlapping portion A, forming a sleeve structure with internal reinforcement effect.

[0027] Through the above structural configuration, the first and second inner liner tubes (40, 50) can form a stable and continuous support interface in the overlapping area of ​​the fork top tube 10 and the first and second fork leg tubes (20, 30), effectively dispersing the stress concentration of external loads in this area, thereby significantly improving the bending strength and shear resistance of the overall fork assembly. Compared with traditional structures that only reinforce by thickening the tube wall or thinning the tube process, this invention can improve the fatigue life of the joint area while maintaining lightweight, preventing cracks or permanent deformation under long-term use, ensuring the stability and durability of the fork structure, and effectively improving its safety and practicality.

Claims

1. A bicycle front fork reinforcement structure, comprising a front fork top tube, a first fork leg tube, and a second fork leg tube; the front fork top tube having a shoulder cover at its bottom end; the first fork leg tube and the second fork leg tube being respectively disposed on both sides of the bottom end of the front fork top tube and extending downwards in a generally parallel manner; characterized in that: The shoulder cover has a first docking cylinder and a second docking cylinder at each end, and each docking cylinder has an insertion hole inside. The upper end of the first fork tube and the second fork tube each has an insertion section, which is inserted into the insertion hole of the first docking cylinder and the second docking cylinder, respectively, so that the first fork tube and the second fork tube overlap with the first docking cylinder and the second docking cylinder, respectively. Inside the first fork tube and the second fork tube, a first inner liner tube and a second inner liner tube are respectively provided, and at least a portion of the first inner liner tube and the second inner liner tube are located within the overlapping portion. Thus, the insertion and overlapping area of ​​the fork top tube and the first fork tube and the second fork tube forms an internal support and reinforcement structure.

2. The bicycle front fork reinforcement structure as described in claim 1, characterized in that: The upper inner hole of the first fork tube and the second fork tube each has a raised section, and the first inner liner tube and the second inner liner tube are respectively inserted into the inner hole area below the raised section.

3. The bicycle front fork reinforcement structure as described in claim 1, characterized in that: The top edges of the insertion holes of the first and second docking cylinders respectively protrude inward to form a retaining flange, which is used to abut and position the upper ends of the first and second fork tubes to limit the insertion depth and improve the stability of the connection.

4. The bicycle front fork reinforcement structure as described in claim 2, characterized in that: The outer diameter of the first inner liner tube and the second inner liner tube is equal to or slightly larger than the inner diameter below the convex section of the corresponding first fork tube and the second fork tube, so that the first inner liner tube and the second inner liner tube can be pressed tightly inside the first fork tube and the second fork tube to form a tight fit.

5. The bicycle front fork reinforcement structure as described in claim 1, characterized in that: The upper outer edge of the first inner lining tube and the second inner lining tube respectively forms a knurled section within the overlapping portion to increase the friction and anti-slip effect with the inner wall of the first fork tube and the second fork tube, thereby further improving the overall bonding strength and reinforcing stability.

6. The bicycle front fork reinforcement structure as described in claim 1, characterized in that: The lower outer edge of the first inner liner tube and the second inner liner tube respectively forms an oblique tapered section to facilitate their insertion and engagement with the first fork tube and the second fork tube.

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