Rim wheel set with side wall in curved surface shape and high and low points arranged alternately
By employing alternating curved high and low points and a spoke mounting hole layout based on a specific functional expression in the bicycle wheel design, the problem of increased wind resistance at different yaw angles in bicycle wheels has been solved, resulting in more efficient aerodynamic performance and riding speed.
Patent Information
- Application Number
- CN202520168077.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-24
- Publication Date
- 2025-12-30
- Estimated Expiration
- 2035-01-24
AI Technical Summary
Existing bicycle rims cannot maintain optimal aerodynamic performance at different yaw angles, resulting in increased wind resistance and affecting riding speed and performance.
Design a wheel assembly with alternating high and low points on the sidewalls, employing a specific curved surface structure and spoke mounting hole layout to satisfy a specific functional expression, thereby optimizing aerodynamic performance.
It effectively reduces air resistance, improves riding speed and performance, and performs better at different yaw angles, enhancing wind-breaking ability.
Smart Images
Figure CN223735770U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to a rim wheel group with alternatingly arranged curved high points and low points on the side wall, which is applied to the field of bicycle rims. BACKGROUND
[0002] The bicycle wheel group is a very important part of the bicycle system, and its weight, rigidity, wind resistance coefficient and other factors have a great influence on the performance of the bicycle. The wheel group is mainly composed of a wheel frame, a hub and spokes, and the combination of the three and the weaving method of the spokes jointly affect the performance of the wheel group. The bicycle wheel group is the part connecting the wheel and the frame, and the power transmission and turning control of the bicycle must be transmitted to the tire through the wheel group, which is a very important part of the bicycle system.
[0003] Most of the bicycle rims on the market adopt a curved structure on the inner side of the rim during design. Although the initial intention of such design is to optimize the aerodynamic performance and reduce wind resistance, in fact, such structure cannot always maintain the best wind breaking effect when facing different yaw angles (i.e. the angle between the bicycle rim and the oncoming wind direction, which changes constantly during riding due to factors such as crosswind and speed). In order to improve the aerodynamic performance of the bicycle rim, especially to improve the performance under various yaw angles, the present application proposes a rim wheel group with alternatingly arranged curved high points and low points on the side wall. SUMMARY
[0004] The utility model provides a rim wheel group with alternatingly arranged curved high points and low points on the side wall, which can effectively solve the above problems.
[0005] The utility model is implemented as follows:
[0006] A rim wheel group with alternatingly arranged curved high points and low points on the side wall, comprising:
[0007] A rim body, including a spoke mounting portion and a tire mounting portion arranged opposite to the spoke mounting portion, the spoke mounting portion being used for mounting a spoke structure, the tire mounting portion being used for mounting a tire, a curved surface structure being arranged on the side wall between the spoke mounting portion and the tire mounting portion in a ring shape with alternatingly arranged curved high points and low points, the curved surface structure satisfying a function expression of a second curve in a vertical cross section along the length direction after the rim body is unfolded along its radial direction; and
[0008] A hub arranged in the rim body, and a spoke structure connecting the hub and the rim body, the spoke structure being fixed on the spoke mounting portion through a threaded connection structure.
[0009] As a further improvement, the cross section of the rim body side wall along its axial direction satisfies a function expression of a first curve.
[0010] As a further improvement, the function expression of the first curve is y=ax²+bx+c (a≠0).
[0011] As a further improvement, the cross-sectional height of the wheel rim body sidewall along its axial direction is defined as... The height of the highest and lowest points of the curved surface from the bottom of the spoke mounting section. =1 / 4~1 / 3 .
[0012] As a further improvement, the functional expression of the second curve is: Where A is the amplitude factor and L is the period of the second curve.
[0013] As a further improvement, the sidewall of the spoke mounting part is provided with a plurality of spoke mounting holes in a circular array, each spoke mounting hole being located at the high point of the curved surface of the spoke mounting part.
[0014] As a further improvement, the number of high points and low points on the surface is 4*N (N is a positive integer).
[0015] As a further improvement, the number of spoke mounting holes is 4*N (N is a positive integer).
[0016] The beneficial effects of this invention are as follows: This invention employs a continuous ring-shaped arrangement of curved high and low points on the sidewall between the spoke mounting section and the tire mounting section of the rim. This unique curved surface structure, based on aerodynamic principles, effectively reduces air resistance encountered by the rim during high-speed riding. This design optimizes the aerodynamic performance of the rim under various yaw angles, thereby enhancing its wind-breaking ability. In short, this innovative rim design, through a specific curved surface layout, improves aerodynamic efficiency under different wind directions, reduces wind resistance, and increases riding speed and performance. Attached Figure Description
[0017] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.
[0018] Figure 1 This is a structural schematic diagram provided in an embodiment of the present invention.
[0019] Figure 2 yes Figure 1 A schematic diagram of the cross-sectional structure at point A in the diagram.
[0020] Figure 3 yes Figure 1 A schematic diagram of the cross-sectional structure at point B in the diagram.
[0021] Figure 4 This is a schematic diagram of the side wall cross-sectional structure when unfolded, provided in an embodiment of the present invention.
[0022] Figures 5-6 This is a comparative example provided by the present invention, showing the drag and drag coefficient analysis at a 0-degree yaw angle.
[0023] Figures 7-8 This is a comparative example provided by the present invention, showing the drag and drag coefficient analysis at a 5-degree yaw angle.
[0024] Figures 9-10 This is a comparative example provided by the present invention, showing the drag and drag coefficient analysis at a 10-degree yaw angle.
[0025] Figures 11-12 This is a comparative example provided by the present invention, showing the drag and drag coefficient analysis at a 15-degree yaw angle.
[0026] Figures 13-14 This is a comparative example provided by the present invention, showing the drag and drag coefficient analysis at a 20-degree yaw angle.
[0027] Figures 15-16 This is an analysis diagram of drag and drag coefficient at a 0-degree yaw angle provided by the present invention.
[0028] Figures 17-18 This is an analysis diagram of drag and drag coefficient at a 5-degree yaw angle provided by the present invention.
[0029] Figures 19-20 This is an analysis diagram of drag and drag coefficient at a 10-degree yaw angle provided by the present invention.
[0030] Figures 21-22 This is an analysis diagram of drag and drag coefficient at a 15-degree yaw angle provided by the present invention.
[0031] Figures 23-24 This is an analysis diagram of drag and drag coefficient at a 20-degree yaw angle provided by the present invention.
[0032] The attached diagram is labeled as follows:
[0033] 10. Wheel rim body; 11. Spoke mounting part; 12. Tire mounting part; 13. Curved surface structure; 131. High point of the curved surface; 132. Low point of the curved surface; 14. Spoke mounting hole. Detailed Implementation
[0034] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model. Therefore, the following detailed description of the embodiments of this utility model provided in the accompanying drawings is not intended to limit the scope of the claimed utility model, but merely to represent selected embodiments of this utility model.
[0035] In the description of this utility model, 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 one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.
[0036] Reference Figures 1-4 As shown, a wheel rim assembly with alternating high and low points on the sidewalls includes:
[0037] The wheel rim body 10 includes a spoke mounting portion 11 and a tire mounting portion 12 disposed opposite to the spoke mounting portion 11. The spoke mounting portion 11 is used to mount the spoke structure, and the tire mounting portion 12 is used to mount the tire. A curved surface structure 13, consisting of an alternating ring of curved surface high points 131 and curved surface low points 132, is formed on the side wall between the spoke mounting portion 11 and the tire mounting portion 12.
[0038] The hub is located inside the wheel rim body, and the spoke structure connects the hub and the wheel rim body.
[0039] The cross-section of the sidewall of the wheel rim body 10 along its axial direction satisfies the function expression of the first curve. The function expression of the first curve is y=ax²+bx+c (a≠0). Without affecting the strength of the wheel rim body 10, it can improve the wind-breaking effect of the wheel rim body 10. It should be noted that in the parabolic expression, y and x may be replaced by different letters depending on the position of the parabola and the plane in which it lies. Furthermore, x in the expression only represents the independent variable, and y only represents the dependent variable, and has no relation to the coordinates xyz.
[0040] The axial section height of the sidewall of the wheel rim body 10 is defined as... The height of the high point 131 and the low point 132 of the curved surface from the bottom of the spoke mounting part 11 is... =1 / 4~1 / 3 In this embodiment, the height of the high point 131 and the low point 132 of the curved surface from the bottom of the spoke mounting portion 11 is... =1 / 3 The advantage of this arrangement is that the curved structure 13 is positioned at the bottom side wall of the wheel rim body 10, and the curved structure 13 forms a certain angle with the radial direction of the wheel rim body 10. This allows the curved structure 13 to have the best wind-breaking effect when the yaw angle is other angles (not 0°).
[0041] After the wheel rim body 10 is unfolded along its radial section, the vertical section of the curved structure 13 along its length direction satisfies the functional expression of the second curve. The functional expression of the second curve is: Where A is the amplitude factor and L is the period of the second curve, this function curve is composed of an approximate brachistochrone. The actual brachistochrone cannot be simply obtained by reversing the sine function in each period. Therefore, this function is an approximate brachistochrone function. This function curve can achieve a similar good wind-breaking effect to the brachistochrone and can also ensure a smooth transition of the curve, further improving the wind-breaking effect. By setting the second curve, during the wheel rotation process, the aerodynamic characteristics are utilized to reduce the air resistance encountered by the wheel rim body 10 during high-speed movement, thereby improving the wind-breaking effect. It should be noted that the direction of the second curve in this case is not limited to the direction set in this case. At the same time, using lines that approximate the brachistochrone in this case, such as hand-drawn lines, polylines, and splines, although they do not satisfy the brachistochrone and parabolic function expressions, can still play a similar role in accelerating the return speed due to approximate drawing. This curve is constructed in the following way:
[0042] First, we know that the equation of a single brachistochrone (starting from the origin in the horizontal direction) can be expressed as:
[0043] y=
[0044] Where g is the acceleration due to gravity and x is the horizontal displacement.
[0045] Secondly, periodicity can be created using sine or cosine functions, and the smoothness of the curve can be ensured by adjusting their parameters, using functions of the following form:
[0046]
[0047] Where f(x) is a periodic function and A is the amplitude factor.
[0048] To make the curve alternate between rising and falling, we can define f(x) as follows:
[0049] =
[0050] Where L is the period of the second curve.
[0051] Substituting f(x) into y(x), we get:
[0052]
[0053] Finally, we introduce a symbolic function sgn to implement this:
[0054]
[0055] Here, sgn(x) is the sign function, which returns 1 when x is positive, -1 when x is negative, and 0 when x is zero.
[0056] The final function y(x) represents a second curve composed of alternating brachistochrones, which rises and falls alternately within each period L while maintaining smoothness. To verify the aerodynamic performance of this wheel rim, refer to... Figures 5-24 As shown, the present invention verifies the wind-breaking effect of the wheel rim body 10 with the curved surface structure 13 through the following simulation experiment:
[0057] First, the product parameters for this embodiment and the comparative example are as follows:
[0058] Table 1 Comparison of Product Parameters
[0059]
[0060] The drag coefficient and drag simulation experiments of the wheel rim were conducted based on different yaw angles. In this embodiment, the selected yaw angles were 0, 5, 10, 15, and 20 degrees. The verification results are shown below:
[0061] Table 2 Comparative Experiment Data Table
[0062]
[0063] Table 3 Experimental data for this embodiment
[0064]
[0065] The integrated data yielded the following results:
[0066] Table 4 Comparison of Integrated Experimental Data
[0067]
[0068] The experimental conclusions are as follows: From the perspective of drag coefficient optimization, the wheel rim in this embodiment shows the most significant optimization effect at a 0-degree yaw angle, and also exhibits good aerodynamic advantages at 10-degree and 20-degree yaw angles. From the perspective of drag, the wheel rim in this embodiment has a more prominent advantage at large yaw angles, making it more suitable for launching attacks from crosswinds, with an advantage of over 4%. Furthermore, with a larger frontal area than ordinary rims, the final drag is lower than that of ordinary rims. The wheel rim design in this embodiment meets the design requirements for optimized aerodynamic structure.
[0069] As a further improvement, a plurality of spoke mounting holes 14 are arranged in a ring array on the sidewall of the spoke mounting part 11. The spoke mounting holes 14 are used to mount spokes, and each spoke mounting hole 14 is located at the high point 131 of the curved surface of the curved structure 13 on the spoke mounting part 11. By utilizing the relatively wide area between the high points of the curved surface of the two annular sidewalls of the spoke mounting part, the machining surface at the location of the spoke mounting holes 14 can be made larger and flatter, making it easier to machine the spoke mounting holes, making spoke installation more convenient, and avoiding the problem of possible skewing after spoke installation.
[0070] The number of high points 131 and low points 132 on the curved surface is 4*N (N is a positive integer), and the number of spoke mounting holes 14 is 4*N (N is a positive integer). In this embodiment, N=5. Therefore, the number of high points 131 and low points 132 on the curved surface is 20, and the number of spoke mounting holes 14 is 20.
[0071] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model.
Claims
1. A wheel assembly, wherein the side walls of the wheel assembly are alternately provided with curved high points and low points, characterized in that, The application relates to a wheel rim body, a hub and a spoke structure. The wheel rim body comprises a spoke mounting portion for mounting a spoke structure and a tire mounting portion opposite to the spoke mounting portion for mounting a tire, a curved surface structure is arranged on a side wall between the spoke mounting portion and the tire mounting portion in a ring shape, the curved surface structure is alternately arranged by a curved surface high point and a curved surface low point, and a vertical section of the curved surface structure along a length direction of the curved surface structure satisfies a function expression of a second curve when the wheel rim body is expanded along a radial direction of the wheel rim body. The hub is arranged in the wheel rim body, and the spoke structure is connected with the hub and the wheel rim body and is fixed on the spoke mounting portion through a threaded connection structure.
2. A wheel assembly with alternating high and low points on the curved sidewalls according to claim 1, characterized in that, A section of the wheel rim body along an axial direction of the wheel rim body satisfies a function expression of a first curve.
3. A wheel assembly with alternating high and low points on the curved sidewalls according to claim 2, characterized in that, The function expression of the first curve is y=ax<2>+bx+c, and a is not equal to 0.
4. The rim wheel assembly of claim 1, wherein the alternating high and low points of the curved sidewalls are arranged in a sinusoidal pattern. The cross-sectional height of the wheel rim body side wall along its axial direction is defined as The height of the high point and the low point of the curved surface from the bottom of the spoke mounting portion is =1 / 4~1 / 3 .
5. The rim wheel assembly of claim 1, wherein the alternating high and low points of the curved sidewalls are formed by a plurality of curved sidewall segments. The function expression of the second curve is: where A is an amplitude factor and L is the period of the second curve.
6. The rim wheel assembly of claim 1, wherein the side walls are curved and the high points and low points of the side walls alternate. A plurality of spoke mounting holes are arranged on the side wall of the spoke mounting portion in a ring shape, and each spoke mounting hole is located at a curved surface high point portion of the curved surface structure on the spoke mounting portion.
7. The rim wheel assembly of claim 6, wherein the alternating high and low points of the curved sidewalls are arranged in a sinusoidal pattern. The number of the curved surface high points and the curved surface low points is 4*N, and N is a positive integer.
8. The rim wheel assembly of claim 7, wherein the alternating high and low points of the curved sidewalls are arranged in a sinusoidal pattern. The number of the spoke mounting holes is 4*N, and N is a positive integer.