Aluminium alloy flat handle road bike

Abstract

The utility model discloses a kind of aluminium alloy flat handle road vehicles, the aluminium alloy flat handle road vehicle includes: the frame group of assembly of pre-set mode, wheel group, transmission system, braking system, handlebar assembly, seat pole, cushion assembly and pedal, frame group includes frame and front fork, front fork cooperation handlebar assembly and wheel group are installed at the front end of frame;Frame includes head tube, upper tube, lower tube, vertical tube, rear triangle and five-way, head tube, upper tube, vertical tube, rear triangle, five-way and lower tube are sequentially connected to form the overall structure of frame;Among them, head tube is provided with first reinforcing structure;Vertical tube is provided with second reinforcing structure;Five-way is provided with third reinforcing structure;Rear triangle is provided with fourth reinforcing structure.The aluminium alloy flat handle road vehicle of the utility model changes the point welding connection in frame structure into area bearing by multiple sleeve connection structures, to optimize the stress distribution of connection node.

Description

Technical Field

[0001] This utility model relates to the field of road bike technology, and in particular to an aluminum alloy flat handlebar road bike. Background Technology

[0002] Aluminum alloy flat-bar road bikes are a product of the accelerated urbanization of the early 21st century. They combine the efficient drivetrain of traditional road bikes with the handling stability of mountain bikes, with core features including: commuting efficiency: 700c wheel diameter + narrow tire design reduces rolling resistance (25% less effort than mountain bikes); versatility: flat-bar geometry lowers the riding threshold (body angle 65°→75°, more upright than drop-bar road bikes); cost control: aluminum alloy frames are only 1 / 3 to 1 / 2 the price of carbon fiber frames. According to the 2023 Global Bicycle Market Report, this category saw a rebound in its share of urban commuter bikes, becoming one of the fastest-growing segments. The development of aluminum alloy frames has iterated along with the development of alloy performance. With the improvement and enhancement of the mechanical strength and processing performance of aluminum alloys, and through breakthroughs in manufacturing processes such as hydroforming, which allows for a wall thickness difference of 0.8-2.5mm (thickening the end of the riser to resist cracking), and variable diameter tube cutting, which reduces the thickness of the middle section by 30% to achieve lightweighting, aluminum alloy frame products can now meet more and wider market demands, such as high strength, lightweight, comfort, or personalized appearance design.

[0003] However, the existing aluminum alloy flat handlebar road bike frame tube connection points have insufficient welding strength when dealing with stronger and more frequent vibration conditions. Utility Model Content

[0004] Therefore, it is necessary to provide an aluminum alloy flat handlebar road bike to address the technical problem of insufficient strength at the connection points of the frame tubes in existing aluminum alloy flat handlebar road bikes.

[0005] A road bike with aluminum alloy flat handlebars includes a frame assembly, wheelset, drivetrain, braking system, handlebar assembly, seatpost, saddle assembly, and pedals assembled in a preset manner. The frame assembly includes a frame and a fork, with the fork mounted at the front end of the frame in conjunction with the handlebar assembly and wheelset.

[0006] The frame includes a head tube, top tube, down tube, seat tube, rear triangle, and bottom bracket. These components are connected sequentially to form the overall frame structure. The head tube has a first reinforcing structure, extending towards both the top tube and the down tube to form a connecting structure. This first reinforcing structure, using the head tube as a support base, connects to the corresponding ends of the top tube and the corresponding ends of the down tube, thus reinforcing the connections between the top tube, down tube, and head tube. The seat tube has a second reinforcing structure located at its top. Its front and rear sides extend towards the top tube and the rear triangle, respectively, forming a connecting structure. This second reinforcing structure, using the top of the seat tube as a support base, connects to the corresponding ends of the top tube and the corresponding ends of the rear triangle, thus reinforcing the connections between the top tube, down tube, and head tube. This reinforces the connection between the top pipe, rear triangle, and riser. The bottom bracket is equipped with a third reinforcing structure, which extends towards the bottom pipe, riser, and rear triangle to form a sleeve structure. The third reinforcing structure, using the bottom bracket as a support base, sleeves onto the corresponding ends of the bottom pipe, riser, and rear triangle connected to the bottom bracket, thus reinforcing the connection between the bottom pipe, riser, rear triangle, and bottom bracket. The rear triangle is equipped with a fourth reinforcing structure, including a rear upper fork and a rear lower fork. The fourth reinforcing structure is located at the connection between the rear upper fork and rear lower fork, extending towards the rear upper fork and rear lower fork to form a sleeve structure. The fourth reinforcing structure, using the rear end of the rear triangle as a support base, sleeves onto the rear end of the rear upper fork and rear lower fork to reinforce the rear end of the rear triangle.

[0007] In one embodiment, the first reinforcing structure includes a first main sleeve and two first secondary sleeves. The first main sleeve is fitted onto the side surface of the head tube. The two first secondary sleeves extend along the extension direction of the upper tube and the lower tube and are respectively disposed on the corresponding side surfaces of the first main sleeve, and are respectively fitted onto the corresponding ends of the upper tube and the lower tube.

[0008] In one embodiment, the first reinforcing structure further includes two first support portions, wherein one first support portion is disposed in the included angle region between the two first first socket portions; and the other first support portion is disposed in the included angle region between the bottom end of the first main socket portion and the adjacent first socket portion.

[0009] In one embodiment, the second reinforcement structure includes a second main sleeve and two secondary sleeves. The second main sleeve is fitted onto the top side surface of the riser. The two secondary sleeves extend along the extension direction of the upper pipe and the rear upper fork and are respectively disposed on the corresponding side surfaces of the second main sleeve, and the two secondary sleeves are respectively fitted onto the corresponding ends of the upper pipe and the rear upper fork.

[0010] In one embodiment, the second reinforcement structure further includes two second support portions, which are respectively disposed in the angle region between the bottom end of the second main sleeve portion and the two side second sleeve portions.

[0011] In one embodiment, the aforementioned third reinforcing structure includes a third main sleeve and three third sleeves. The third main sleeve is fitted onto the side surface of the bottom bracket. The three third sleeves extend along the extension directions of the lower pipe, the riser, and the rear lower fork, respectively, and are respectively fitted onto the corresponding side surfaces of the third main sleeve.

[0012] In one embodiment, the aforementioned third reinforcing structure further includes two third support portions, which are respectively disposed in the included angle region between the three third sleeve portions.

[0013] In one embodiment, the aforementioned fourth reinforcing structure includes two fourth sleeve portions, which are respectively fitted onto the rear ends of the upper rear fork and the lower rear fork.

[0014] In one embodiment, the aforementioned fourth reinforcing structure further includes a fourth support portion disposed in the included angle region between the two fourth sleeve portions.

[0015] In one embodiment, each of the connecting portions of the first, second, third, and fourth reinforcing structures described above is configured as a sleeve structure.

[0016] In one embodiment, the above-mentioned sleeve structure is interference-fitted with the corresponding sleeve body. The sleeve structure of each sleeve part is placed in liquid nitrogen and cooled to -196°C for 10 minutes. The head tube is heated to 180°C±5°C and held for 15 minutes. The sleeve is pressed into the head tube with a hydraulic press at a pressure of 50kN and the interference is 0.06mm.

[0017] In one embodiment, the sleeve structure and the corresponding sleeved tube are filled with a damping adhesive layer. The damping adhesive is a silicone-based adhesive with 15 wt% silica nanoparticles (particle size 30 nm) and a thickness of 0.2 mm. The damping adhesive layer is cured in a vacuum autoclave at a temperature of 120°C, a pressure of 0.8 MPa, and a time of 45 min.

[0018] In one embodiment, the supporting parts of the first, second, third, and fourth reinforcing structures described above are configured as rib structures with a thickness of 3-6 mm.

[0019] The aforementioned aluminum alloy flat handlebar road bike transforms spot-welded connections in the frame structure into surface-load-bearing structures through multiple sleeve structures, thereby optimizing the stress distribution at the connection nodes. The sleeve method allows for non-fixed connections between each sleeve structure and each tube body. Based on the independent deformation space of each sleeve structure, the absorption capacity of the sleeve structure for high-frequency vibrations of the corresponding tube body is improved, enhancing vibration damping performance. Based on the reinforcement of each tube body connection by each sleeve structure, the plastic deformation of the sleeve surface can effectively reduce the risk of brittle fracture at the weld of the tube body components. Specifically, the first reinforcement structure forms a root-like wrapping connection to disperse lateral torsional loads during steering and suppress torque peaks at the head tube and adjacent critical connections; the second reinforcement structure resists longitudinal pressure caused by rider weight through bidirectional sleeve connection, while reducing elliptical deformation of the top of the seat tube during pedaling; the third reinforcement structure can transmit pedaling torque in multiple directions, reducing stress concentration at the bottom bracket shell edge; the fourth reinforcement structure sleeves the rear dropout at the rear fork and rear chainstay ends to improve the lateral rigidity of the wheelset and suppress the deformation amplification effect during pedaling. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of an aluminum alloy flat handlebar road bike in one embodiment;

[0021] Figure 2 for Figure 1 A schematic diagram of the aluminum alloy flat handlebar road bike from another perspective in the embodiment shown. Detailed Implementation

[0022] To make the above-mentioned objects, 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. Many specific details are set forth in the following description to provide a full understanding of this utility model. However, this utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this utility model. Therefore, this utility model is not limited to the specific embodiments disclosed below.

[0023] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0024] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this utility model, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0025] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0026] In this utility model, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0027] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0028] Please see Figures 1 to 2This utility model discloses an aluminum alloy flat handlebar road bike 1, which includes a frame assembly 10, wheelset 20, drivetrain 30, braking system 40, handlebar assembly 50, seatpost 60, saddle assembly 70, and pedals 80 assembled in a preset manner. The frame assembly 10 includes a frame 11 and a front fork 12, which is mounted on the front end of the frame 11 in conjunction with the handlebar assembly 50 and wheelset 20. Specifically, the frame 11 includes a head tube 111, top tube 112, down tube 113, seat tube 114, rear triangle, and bottom bracket 117, which are sequentially connected to form the overall frame 11 structure. The head tube 111 is provided with a first reinforcing structure a, which is respectively positioned on the side facing the top tube 112 and the side facing the down tube 113. The first reinforcing structure a extends to form a sleeve structure. Then, the first reinforcing structure a, using the head pipe 111 as a supporting base, sleeves onto the corresponding ends of the upper pipe 112 and the lower pipe 113 connected to the head pipe 111, thereby reinforcing the connection between the upper pipe 112, the lower pipe 113, and the head pipe 111. The riser 114 is provided with a second reinforcing structure b, located at the top of the riser 114. The front and rear sides of the second reinforcing structure b extend towards the upper pipe 112 and the rear triangular direction, respectively, to form a sleeve structure. Then, the second reinforcing structure b, using the head pipe 111 as a supporting base, sleeves onto the corresponding ends of the upper pipe 112 and the lower pipe 113 connected to the head pipe 111, thereby reinforcing the connection between the upper pipe 112, the lower pipe 113, and the head pipe 111. To support the foundation, the connection between the upper pipe 112 (connected to the riser 114) and the corresponding end of the rear triangle is sleeved onto the bottom bracket 117 to reinforce the connection between the upper pipe 112, the rear triangle, and the riser 114. The bottom bracket 117 is equipped with a third reinforcing structure c, which extends towards the lower pipe 113, the riser 114, and the rear triangle to form a sleeved structure. The third reinforcing structure c uses the bottom bracket 117 as a supporting foundation and sleeves onto the corresponding ends of the lower pipe 113, the riser 114, and the rear triangle connected to the bottom bracket 117. The end is used to reinforce the connection between the lower pipe 113, the riser 114, and the rear triangle and the bottom bracket 117. The rear triangle is provided with a fourth reinforcement structure d. The rear triangle includes a rear upper fork 115 and a rear lower fork 116. The fourth reinforcement structure d is provided at the connection between the rear ends of the rear upper fork 115 and the rear lower fork 116. The fourth reinforcement structure d extends towards the rear upper fork 115 and the rear lower fork 116 to form a sleeve structure. Then, the fourth reinforcement structure d uses the rear end of the rear triangle as a support base and sleeves onto the rear end of the rear upper fork 115 and the rear end of the rear lower fork 116 to reinforce the rear end of the rear triangle.Based on the above configuration, the aluminum alloy flat handlebar road bike 1 of this utility model transforms the spot welding connection in the frame 11 structure into a surface load-bearing structure through multiple sleeve structures, thereby optimizing the stress distribution of the connection nodes; the sleeve method allows for non-fixed connections between each sleeve structure and each tube body, and based on the independent deformation space of each sleeve structure, the absorption capacity of the sleeve structure for high-frequency vibration of the corresponding tube body is improved, enhancing the vibration damping performance; based on the reinforcement of each tube body connection by each sleeve structure, the plastic deformation of the sleeve surface can effectively reduce the risk of brittle fracture at the weld of the tube body component. Specifically, the first reinforcement structure a forms a root-like wrapping connection to disperse the lateral torsional load during steering and suppress the torque peak at the head tube 111 and adjacent key connection points; the second reinforcement structure b resists the longitudinal pressure caused by the rider's weight through a bidirectional sleeve connection, while reducing the elliptical deformation of the top of the seat tube 114 during pedaling; the third reinforcement structure c can transmit pedaling torque in multiple directions, reducing the concentration of stress at the edge of the bottom bracket 117 housing; the fourth reinforcement structure d sleeves the rear dropout at the rear upper fork 115 and the rear lower fork 116 ends, thereby improving the lateral rigidity of the wheelset 20 and suppressing the deformation amplification effect.

[0029] Furthermore, the first reinforcing structure a includes a first main sleeve a1 and two first secondary sleeves a2. The first main sleeve a1 fits onto the side surface of the head tube 111. The two first secondary sleeves a2 extend along the extension directions of the upper tube 112 and the lower tube 113, respectively, and are disposed on the corresponding side surfaces of the first main sleeve a1, and are respectively fitted onto the corresponding ends of the upper tube 112 and the lower tube 113. Based on this, the first reinforcing structure a also includes two first support parts a3, one of which is disposed in the included angle region between the two first secondary sleeves a2; the other first support part a3 is disposed in the included angle region between the bottom end of the first main sleeve a1 and the adjacent first secondary sleeve a2, thereby further enhancing the reinforcing function of the first reinforcing structure a.

[0030] Furthermore, the second reinforcing structure b includes a second main sleeve portion b1 and two secondary sleeve portions b2. The second main sleeve portion b1 is fitted onto the top side surface of the riser 114. The two secondary sleeve portions b2 extend along the extension direction of the upper pipe 112 and the rear upper fork 115, respectively, and are disposed on the corresponding side surfaces of the second main sleeve portion b1, and are respectively fitted onto the corresponding ends of the upper pipe 112 and the rear upper fork 115. Based on this, the second reinforcing structure b also includes two second support portions b3, which are respectively disposed in the angled area between the bottom end of the second main sleeve portion b1 and the two secondary sleeve portions b2, thereby further enhancing the reinforcing function of the second reinforcing structure b.

[0031] Furthermore, the third reinforcing structure c includes a third main sleeve c1 and three third sleeves c2. The third main sleeve c1 is fitted onto the side surface of the bottom bracket 117. The three third sleeves c2 extend along the extension directions of the lower pipe 113, the riser 114, and the rear lower fork 116, respectively, and are respectively disposed on the corresponding side surfaces of the third main sleeve c1. The three third sleeves c2 are respectively fitted onto the corresponding ends of the lower pipe 113, the riser 114, and the rear lower fork 116. Based on this, the third reinforcing structure c also includes two third support parts c3, which are respectively disposed in the included angle area between the three third sleeves c2, thereby further enhancing the reinforcing function of the third reinforcing structure c.

[0032] Furthermore, the fourth reinforcing structure d includes two fourth sleeve portions d1, which are respectively fitted onto the rear ends of the upper rear fork 115 and the lower rear fork 116. Based on this, the fourth reinforcing structure d also includes a fourth support portion d2, which is disposed in the included angle region between the two fourth sleeve portions d1, thereby further enhancing the reinforcing function of the fourth reinforcing structure d.

[0033] Furthermore, each of the connecting parts of the first reinforcing structure a, the second reinforcing structure b, the third reinforcing structure c, and the fourth reinforcing structure d is configured as a sleeve structure. In one embodiment, the sleeve structure is interference-fitted with the corresponding sleeve body. Specifically, the sleeve structure of each connecting part is placed in liquid nitrogen and cooled to -196°C for 10 minutes; the head tube 111 is heated to 180°C ± 5°C and held for 15 minutes; the sleeve is pressed into the head tube 111 with a hydraulic press at a pressure of 50 kN, with an interference fit of 0.06 mm. In another embodiment, the sleeve structure and the corresponding sleeve body are filled with a damping adhesive layer. Specifically, the damping adhesive is a silicone-based adhesive doped with 15 wt% silica nanoparticles (particle size 30 nm) with a thickness of 0.2 mm. The damping adhesive layer is cured in a vacuum autoclave at a temperature of 120°C, a pressure of 0.8 MPa, and a time of 45 minutes.

[0034] Furthermore, the support parts of the first reinforcement structure a, the second reinforcement structure b, the third reinforcement structure c, and the fourth reinforcement structure d are all configured as rib structures with a thickness of 3-6mm, thereby strengthening the torsional resistance of the tube connections while avoiding an excessive increase in the weight of the frame 11.

[0035] In summary, the aluminum alloy flat handlebar road bike disclosed in this utility model transforms spot-welded connections in the frame structure into surface-load-bearing structures through multiple sleeve structures, thereby optimizing the stress distribution at the connection nodes. The sleeve method allows for non-fixed connections between each sleeve structure and each tube body. Based on the independent deformation space of each sleeve structure, the absorption capacity of the sleeve structure for high-frequency vibrations of the corresponding tube body is improved, enhancing vibration damping performance. Furthermore, the reinforcement of the tube body connections by each sleeve structure, through the plastic deformation of the sleeve surface, effectively reduces the risk of brittle fracture at the weld seams of the tube components. Specifically, the first reinforcement structure forms a root-like wrapping connection to disperse lateral torsional loads during steering and suppress torque peaks at the head tube and adjacent critical connections; the second reinforcement structure resists longitudinal pressure caused by rider weight through bidirectional sleeve connection, while reducing elliptical deformation of the top of the seat tube during pedaling; the third reinforcement structure can transmit pedaling torque in multiple directions, reducing stress concentration at the bottom bracket shell edge; the fourth reinforcement structure sleeves the rear dropout at the rear fork and rear chainstay ends to improve the lateral rigidity of the wheelset and suppress the deformation amplification effect during pedaling.

[0036] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0037] The embodiments described above are merely illustrative of several implementations of this utility model, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

Claims

1. A road bike with aluminum alloy flat handlebars, characterized in that, include: The frame assembly, wheelset, drivetrain, braking system, handlebar assembly, seatpost, saddle assembly, and pedals are assembled in a preset manner. The frame assembly includes the frame and the fork, with the fork mounted on the front end of the frame in conjunction with the handlebar assembly and wheelset. The frame includes a head tube, top tube, down tube, seat tube, rear triangle, and bottom bracket. The head tube, top tube, seat tube, rear triangle, bottom bracket, and down tube are connected in sequence to form the overall frame structure. The head tube has a first reinforcing structure, which extends towards one side of the top tube and one side of the down tube to form a connecting structure. The seat tube has a second reinforcing structure, which is located at the top of the seat tube. The front and rear sides of the second reinforcing structure extend towards the top tube and rear triangle to form a connecting structure. The bottom bracket has a third reinforcing structure, which extends towards one side of the down tube, one side of the seat tube, and one side of the rear triangle to form a connecting structure. The rear triangle has a fourth reinforcing structure, which includes a rear top fork and a rear bottom fork. The fourth reinforcing structure is located at the connection point of the rear ends of the rear top fork and the rear bottom fork, and extends towards the rear top fork and the rear bottom fork to form a connecting structure.

2. The aluminum alloy flat handlebar road bike according to claim 1, characterized in that, The first reinforcing structure includes a first main sleeve and two first primary sleeves. The first main sleeve is fitted onto the side surface of the head tube. The two first primary sleeves extend along the extension direction of the upper tube and the lower tube and are respectively disposed on the corresponding side surfaces of the first main sleeve, and the two first primary sleeves are respectively fitted onto the corresponding ends of the upper tube and the lower tube.

3. The aluminum alloy flat handlebar road bike according to claim 2, characterized in that, The first reinforcing structure also includes two first support parts, one of which is located in the angled region between the two first socket parts; the other first support part is located in the angled region between the bottom end of the first main socket part and the adjacent first socket part.

4. The aluminum alloy flat handlebar road bike according to claim 3, characterized in that, The second reinforcing structure includes a second main sleeve and two secondary sleeves. The second main sleeve is fitted onto the top side surface of the riser. The two secondary sleeves extend along the extension direction of the upper pipe and the rear upper fork and are respectively disposed on the corresponding side surfaces of the second main sleeve, and the two secondary sleeves are respectively fitted onto the corresponding ends of the upper pipe and the rear upper fork.

5. The aluminum alloy flat handlebar road bike according to claim 4, characterized in that, The second reinforcing structure also includes two second support parts, which are respectively located in the angled area between the bottom end of the second main sleeve and the two second sleeve parts on both sides.

6. The aluminum alloy flat handlebar road bike according to claim 5, characterized in that, The third reinforcement structure includes a third main sleeve and three third sleeves. The third main sleeve is fitted onto the side surface of the bottom bracket. The three third sleeves extend along the extension direction of the bottom pipe, the riser and the rear bottom fork, respectively, and are respectively fitted onto the corresponding side surface of the third main sleeve.

7. The aluminum alloy flat handlebar road bike according to claim 6, characterized in that, The third reinforcement structure also includes two third support parts, which are respectively located in the included angle area between the three third sleeve parts.

8. The aluminum alloy flat handlebar road bike according to claim 7, characterized in that, The fourth reinforcement structure includes two fourth sleeve parts, which are respectively fitted onto the rear ends of the upper rear fork and the lower rear fork.

9. The aluminum alloy flat handlebar road bike according to claim 8, characterized in that, The fourth reinforcement structure also includes a fourth support, which is located in the angled area between the two fourth fittings.

10. The aluminum alloy flat handlebar road bike according to claim 9, characterized in that, The connecting parts of the first, second, third, and fourth reinforcing structures are all configured as sleeve structures.

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