Patent Publication Number: US-2021187999-A1

Title: Bicycle rim

Description:
FIELD OF THE INVENTION 
     The present disclosure relates to a rim for a bicycle, and more particularly to a rim capable of decreasing wind resistance. 
     BACKGROUND OF THE INVENTION 
     A design of a bicycle should consider a wind resistance effect when the bicycle is riding at high speed. A racing bicycle is usually designed to allow a rider to ride in a streamlined prone position. However, when a bicycle moves, wheels of the bicycle may suffer from wind resistance. 
     A wheel of a bicycle includes a rim and a tire secured to the rim. The rim for supporting the tire has two opposite side surfaces. In order to decrease a wind resistance of a fast turning wheel, each of the side surfaces is usually designed to be a smooth surface to decrease a cross sectional area of a windward surface thereof. However, when a wheel is turning, a laminar boundary layer may be formed on each of the smooth side surfaces of the wheel, and the laminar boundary layer may further develop into a turbulent flow when a vehicle speed gradually increases, thereby causing a resistance to the wheel turning. 
     In addition, for the requirements of bicycle speed races, a rim height of a bicycle rim increases with the increasing bicycle speed, therefore a larger side surface height of a rim is used by more and more rims, thereby making the aforementioned problem of turbulent more obvious. 
     SUMMARY OF THE INVENTION 
     The present disclosure provides a rim, which has a spoiler portion to decrease a turbulent flow when a wheel of a bicycle is turning, thereby raising riding efficiency. 
     The present disclosure provides a rim applied to a bicycle, wherein the rim rotates about an axis and includes a rim body and a spoiler portion. The rim body is annular and has two opposite side surfaces. The two side surfaces are connected by an intermediate portion. Each of the side surfaces has a radial inner portion and a radial outer portion. The radial inner portion of one of the side surfaces is located on a radial inner side defined by a radial direction and gradually inclined toward the other side surface. The radial outer portion is located on a radial outer side defined by the radial direction. The radial outer portion has an extension portion and a radial outer periphery at the outermost side along the radial direction. The extension portion is extended toward the radial outer side from a connecting portion between the radial outer portion and the intermediate portion. The spoiler portion has a plurality of spoiler profiles. The plurality of spoiler profiles is concavely formed on the radial outer portion of at least one of the two side surfaces, and at least one of the plurality of spoiler profiles is partially disposed on the extension portion without forming any undulation on the radial outer periphery. 
     In an embodiment of the present disclosure, a brake surface is disposed on at least one of the two side surfaces, and the spoiler portion is disposed between the brake surface and the radial outer portion. 
     In an embodiment of the present disclosure, the plurality of spoiler profiles of the spoiler portion is regularly arranged as a plurality of spoiler profile groups. 
     In an embodiment of the present disclosure, each of the spoiler profile groups includes two first spoiler profiles respectively located at two ends, a second spoiler profile located in central and a plurality of third spoiler profiles located between the two first spoiler profiles and the second spoiler profile. Lengths of the third spoiler profiles are gradually changed from the two first spoiler profiles to the second spoiler profile. 
     In an embodiment of the present disclosure, the lengths of the third spoiler profiles are gradually increased from the two first spoiler profiles to the second spoiler profile. 
     In an embodiment of the present disclosure, the plurality of spoiler groups is arranged parallel to each other and spaced at an equal distance. 
     In an embodiment of the present disclosure, one of the two first spoiler profiles is respectively disposed on a main body of the extension portion, and the other one is disposed on a main body of the radial outer portion. 
     In an embodiment of the present disclosure, the adjacent spoiler profiles have unequal lengths. 
     In an embodiment of the present disclosure, distances between tops of the plurality of spoiler profiles and the radial outer portion are gradually increased in a rotating direction, and the rotating direction is a direction in which the rim drives the bicycle to move. 
     In an embodiment of the present disclosure, the plurality of spoiler profiles is distributed at equal distances on the radial outer portion. 
     In an embodiment of the present disclosure, each of the plurality of spoiler profiles has a first opening facing the extension portion and a second opening facing the radial inner portion, wherein a width of the first opening is greater than a width of the second opening. 
     In an embodiment of the present disclosure, a first side wall and a second side wall opposite to the first side wall are connected between the first opening and the second opening of each of the plurality of spoiler profiles, wherein an inclination of the first side wall is smaller than an inclination of the second side wall. 
     In an embodiment of the present disclosure, the first side wall has a first end on the first opening and a second end on the second opening. The second end is disposed behind the first end in a rotating direction, and the rotating direction is a direction in which the rim drives the bicycle to move. 
     In an embodiment of the present disclosure, the spoiler portion has a maximum depth not less than 0.25 mm and not greater than 4.5 mm. 
     In an embodiment of the present disclosure, the spoiler portion has a maximum radial length not less than 0.1 mm and not greater than 300 mm. 
     According to above description, since a spoiler portion is disposed on the side surfaces of the rim of the present disclosure, airflow can be guided by the spoiler portion when the wheel rotates to reduce the possibility that a laminar boundary layer develops into a turbulent flow and reduce the air resistance experienced by the wheels, thereby improving riding efficiency. 
     Other objectives, features and advantages of the invention will be further understood from the further technological features disclosed by the embodiments of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present disclosure will become more readily apparent to those ordinarily skilled in the art after reviewing the following detailed description and accompanying drawings, in which: 
         FIG. 1A  is a schematic view of a wheel of an embodiment of the present disclosure; 
         FIG. 1B  and  FIG. 1C  are schematic partially enlarged views of a rim of an embodiment of the present disclosure; 
         FIG. 1D  is a schematic cross-sectional view taken along the line A-A in  FIG. 1C ; 
         FIG. 2A  and  FIG. 2B  are schematic partially enlarged views of a rim of another embodiment of the present disclosure; 
         FIG. 2C  is a schematic cross-sectional view taken along the line B-B in  FIG. 2B ; and 
         FIG. 3A  and  FIG. 3B  are schematic flow field views caused by a moving wheel in a conventional art and in an embodiment of the present disclosure, respectively. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     The present disclosure will now be described more specifically with reference to the following embodiments. It is to be noted that the following descriptions of preferred embodiments of this invention are presented herein for purpose of illustration and description only. It is not intended to be exhaustive or to be limited to the precise form disclosed. 
       FIG. 1A  is a schematic view of a wheel of an embodiment of the present disclosure.  FIG. 1B  and  FIG. 1C  are schematic partially enlarged views of a rim of an embodiment of the present disclosure. FIG.  1 D is a schematic cross-sectional view taken along the line A-A in  FIG. 1C . Please refer to  FIG. 1A  to  FIG. 1D . A wheel  10  of the embodiment includes a rim  100  and a tire  200 . The wheel  10  can rotate about an axis  113  along a rotating direction D 1  to move a bicycle forward. The rim  100  includes a rim body  110  and a spoiler portion  120 . The rim body  110  is annular and has two opposite side surfaces  111  and an intermediate portion  112  disposed between the two side surfaces  111 . The intermediate portion  112  is connected to the two side surfaces  111 . In general, the intermediate portion  112  can be an annular concave portion. The size of the tire  200  is fitted to the intermediate portion  112 , and the wheel  10  is assembled by embedding a portion of the tire  200  into the intermediate portion  112 . In addition, the rim  100  further includes a plurality of spokes  114  connected between the axis  113  and a radial inner periphery of the rim body  110 . 
     Each of the two opposite side surfaces  111  of the rim body  110  has a radial inner portion  1112 , a radial outer portion  1113  and an extension portion  1114 . The radial inner portion  1112  of any of the side surfaces  111  is located on a radial inner side and gradually inclined toward the other side surface  111 . One of the radial outer portions  1113  is located on a radial outer side and is substantially parallel to the other radial outer portion  1113 . The radial outer portion  1113  is radially farther from the axis  113  than the radial inner portion  1112 . That is, the radial outer portion  1113  is located outside the radial inner portion  1112  in the radial direction al of the axis  113 . The extension portion  1114  is extended toward outside from the radial outer portion  1113  in an axis direction r 1  of the axis  113 , and the extension portion  1114  has a radial outer periphery  1116  on the outmost side thereof. Specifically, the extension portion  1114  is extended from one of the radial outer portions  1113  toward the other radial outer portion  1113  along the axis direction r 1 . The extension portion  1114  may be in contact with the tire  200  when the tire  200  is assembled to the rim  100 . The spoiler portion  120  is disposed on at least one of the two side surfaces  111  and is concavely formed on the side surface  111 . The spoiler portion  120  is disposed on the radial outer portion  1113 , and at least a portion of the spoiler portion  120  is disposed on the extension portion  1114  without exceeding the extension portion  1114 . That is, the spoiler portion  120  does not form any undulation on the radial outer periphery  1116  so as to prevent from contacting the tire  200  or damaging a tire wall of the tire  200 . In the embodiment, each of the side surfaces  111  further includes a brake surface  1115  close to the radial inner portion  1112 . The spoiler portion  120  is disposed on at least one of the two side surfaces  111  and is disposed between the brake surface  1115  and the radial outer periphery  1116 , but is not limited thereto. For example, the brake surface  1115  can be omitted when the rim  100  is a disc-brake rim, and the spoiler portion  120  is disposed between the radial outer portion  1112  and the radial outer periphery  1116 . 
     The spoiler portion  120  has a plurality of spoiler profiles such as the first spoiler profiles  1211   a ,  1211   b  and the third spoiler profiles  1213  to be described later. The plurality of spoiler profiles is concavely formed on the radial outer portion  1113  of at least one of the two side surfaces  111 , and at least a part of the plurality of spoiler profiles is partially disposed on the extension portion  1114  without forming any undulation on the radial outer periphery  1116 . In the embodiment, a portion of the spoiler portion  120  is disposed on the extension portion  1114  of each of the two side surfaces  111 , but is not limited thereto. 
     In the embodiment as shown in  FIG. 1B  and  FIG. 1C , the spoiler portion  120  includes a plurality of spoiler profile groups  121 . Each of the plurality of spoiler profile groups  121  includes a plurality of parallelly-arranged spoiler profiles recessed from the side surface  111  toward the intermediate portion  112 . The plurality of spoiler profiles includes two first spoiler profiles  1211   a ,  1211   b  respectively located at two ends, at least one second spoiler profile  1212  located in central and a plurality of third spoiler profiles  1213  located between the two first spoiler profiles  1211   a ,  1211   b  and the second spoiler profile  1212 . The lengths of the plurality of third spoiler profiles  1213  are gradually changed from the two first spoiler profiles  1211   a ,  1211   b  to the second spoiler profile  1212 , so that the adjacent spoiler profiles have unequal lengths in the embodiment. In addition, the plurality of spoiler profiles groups  121  is arranged parallel to each other and spaced at an equal distance. 
     In the embodiment, the lengths of the plurality of third spoiler profiles  1213  are gradually increased from the two first spoiler profiles  1211   a ,  1211   b  to the second spoiler profile  1212 . The first spoiler profiles  1211   a ,  1211   b  have a first length L 1 , the second spoiler profile  1212  has a second length L 2 , and the third spoiler profiles  1213  have a third length L 3 . The second length L 2  is greater than both of the first length L 1  and the third length L 3 . The third length L 3  is greater than the first length L 1 . 
     In addition, since at least a portion of the spoiler portion  120  is disposed on the extension portion  1114 , one first spoiler profile  1211   a  of the spoiler profile group  121  is disposed on the extension portion  1114 , and the other first spoiler profile  1211   b  is disposed on the radial outer portion  1113 . In more detail, a distance X between a top of each of the plurality of spoiler profiles in the spoiler profile group  121  and the brake surface  1115  is gradually decreased from the first rotating direction D 1  toward a second rotating direction D 2  opposite to the first rotating direction D 1 . In other words, a distance between a top of each of the plurality of spoiler profiles and the radial outer periphery  1116  is gradually increased in the first rotating direction D 1 . The first rotating direction D 1  is a direction in which the rim  100  drives the bicycle to move. In the embodiment, a first distance between a top of the first spoiler profile  1211   a  and the brake surface  1115  is X 1 , a second distance between a top of the second spoiler profile  1212  and the brake surface  1115  is X 2 , and a third distance between a top of the other first spoiler profile  1211   b  and the brake surface  1115  is X 3 . The first distance X 1  is greater than both of the second distance X 2  and the third distance X 3 , and the second distance X 2  is greater than the third distance X 3 . 
     Please refer to  FIG. 1C . Since the distance X of the top of each of the plurality of spoiler profiles in the spoiler profile group  121  and the brake surface  1115  is gradually decreased from the first rotating direction D 1  toward the second rotating direction D 2  opposite to the first rotating direction D 1 , the spoiler profile group  121   a  and another spoiler profile group  121   b  can be partially disposed on a common radial surface. In more detail, the first spoiler profile  1211   b  of the spoiler profile group  121   a  and another first spoiler profile  1211   b  of another spoiler profile group  121   b  can be disposed on a common radial surface. The first spoiler profile  1211   b  of the spoiler profile group  121   a  is closer to the brake surface  1115  than the other first spoiler profile  1211   a  of another spoiler profile group  121   b , and the other first spoiler profile  1211   a  of another spoiler profile group  121   b  is closer to the extension portion  1114  than the first spoiler profile  1211   b  of the spoiler profile group  121   a.    
     In the embodiment, not only the first spoiler profile  1211   b  of the spoiler profile group  121   a  and another first spoiler profile  1211   b  of another spoiler profile group  121   b  can be disposed on a common radial surface, a part of the third spoiler profiles  1213  of the spoiler profile group  121   a  and a part of the third spoiler profiles  1213  of another spoiler profile group  121   b  are disposed on a common radial surface. 
     Please refer to  FIG. 1D . The spoiler portion  120  has a maximum depth W and a maximum radial length L. The maximum depth W is not less than 0.25 mm and not greater than 4.5 mm, and the maximum radial length L is not less than 0.1 mm and not greater than 300 mm. Any second spoiler profile  1212  can have both of the maximum radial length L and the maximum depth W. 
     According to above description, since the spoiler portion  120  is disposed on the side surface  111  of the rim  100  of the embodiment, airflow can be guided by the spoiler portion  120  when the wheel  10  rotates to reduce the possibility that a laminar boundary layer develops into a turbulent flow and reduce the air resistance experienced by the wheels  10 , thereby improving riding efficiency. 
       FIG. 2A  and  FIG. 2B  are schematic partially enlarged views of a rim of another embodiment of the present disclosure.  FIG. 2C  is a schematic cross-sectional view taken along the line B-B in  FIG. 2B . Please refer to  FIG. 2A  to  FIG. 2C . The rim  100 ′ of the embodiment is substantially the same as the rim  100  of  FIG. 1A , and the difference is that the spoiler portion  120 ′ of the rim  100 ′ of the embodiment includes a plurality of spoiler profiles  122  distributed at equal distances. Each of the plurality of spoiler profiles  122  is recessed from the side surface  111  toward the intermediate portion  112 . 
     In the embodiment, each of the plurality of spoiler profiles  122  has a first opening  1221  facing the extension portion  1114  and a second opening  1222  facing the brake surface  1115 . A width of the first opening  1221  is greater than a width of the second opening.  1222 . Specifically, a first side wall  1223  and a second side wall  1224  opposite to the first side wall  1223  are connected between the first opening  1221  and the second opening  1222  of each of the plurality of spoiler profiles  122 . For guiding airflow, the first side surface  1223  can be a smooth curved surface, and the second side surface can be a flat surface. The first side surface  1223  is extended from the first opening  1221  to the second surface  1222  along the second rotating direction D 2  to form a curved surface. In more detail, a first end  1223   a  of the first side surface  1223  located at the first opening  1221  is disposed more toward the first rotating direction D 1  than a second end  1223   b  located at the second opening  1222 . 
     Please refer to  FIG. 2C . The spoiler portion  120 ′ has a maximum depth W′ and a maximum radial length L′. The maximum depth W′ is not less than 0.25 mm and not greater than 4.5 mm, and the maximum radial length L′ is not less than 0.1 mm and not greater than 300 mm. 
       FIG. 3A  and  FIG. 3B  are schematic flow field views caused by a moving wheel in a conventional art and in an embodiment of the present disclosure, respectively. Please refer to  FIG. 3A . If the wheel  10  of  FIG. 1A  does not have the spoiler portion  120 , airflow F 1  (shown by the arc arrows) will cause backflow at the joint between the tire  200  and the rim  100  to form a dragging force on the wheel  10 , thereby reducing a smoothness of the airflow F 1 . In contrast, because the wheel  10  of  FIG. 3B  has the spoiler portion  120 , the backflow supposed to be occurred at the joint between the tire  200  and the rim  100  can be eliminated by the spoiler portion  120 , so that the airflow F 2  can be significantly smoother than the airflow F 1  in  FIG. 3A , therefore reducing the bearing resistance of the tire  10 . 
     According to above description, since a spoiler portion is disposed on the side surfaces of the rim of the present disclosure, airflow can be guided by the spoiler portion when the wheel rotates to reduce the possibility that a laminar boundary layer develops into a turbulent flow and reduce the air resistance experienced by the wheels, thereby improving riding efficiency. 
     While the invention has been described in terms of what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention needs not be limited to the disclosed embodiment. On the contrary, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims which are to be accorded with the broadest interpretation so as to encompass all such modifications and similar structures.