Aerodynamic Bicycle Disc Wheel Assembly

Abstract

An aerodynamic disc wheel assembly includes a pair of generally symmetrical hourglass shaped sidewalls extending from a hub to a brake engaging portion of a wheel. The sidewalls include a radially inwardly positioned widened hub portion, a radially outwardly disposed brake engaging portion, and a two part central portion extending between the hub portion and the brake engaging portion. The assembly further includes an oval shaped end cap for engaging the disc wheel to spinningly receive a bicycle hub.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

A clear conception of the advantages and features constituting the present invention, and of the construction and operation of typical mechanisms provided with the present invention, will become more readily apparent by referring to the exemplary, and therefore non-limiting, embodiments illustrated in the drawings accompanying and forming a part of this specification, wherein like reference numerals designate the same elements in the several views, and in which:

FIG. 1 is an elevational view of a bicycle equipped with a disc wheel assembly according to the present invention;

FIG. 2 is an elevational view of the disc wheel assembly shown in FIG. 1;

FIG. 3 is a cross-sectional view of the disc wheel assembly along line 3-3 shown in FIG. 2;

FIG. 4 is a detailed cross-sectional view of a rim area of the disc wheel assembly along line 4-4 shown in FIG. 3;

FIG. 5 is a detailed cross-sectional view of a hub area of the disc wheel assembly along line 5-5 shown in FIG. 3.

FIG. 6 is a perspective view of an end cap of the disc wheel assembly shown in FIG. 3;

FIG. 7 is a cross-sectional view of the end cap along line 7-7 shown in FIG. 6;

FIG. 8 is a cross-sectional view of the end cap along line 8-8 shown in FIG. 6 and is a view generally transverse to the view shown in FIG. 7;

FIG. 9 is a graph showing the association of wind angle and aerodynamic drag force for the disc wheel assembly shown in FIG. 1 with and without implementation of the end cap shown in FIG. 6; and

FIG. 10 is a graph showing the lateral deflection of the disc wheel assembly shown in FIG. 2 as compared to various known disc wheel assemblies.

Claims

1. An aerodynamic disc wheel assembly comprising a pair of symmetrical hourglass shaped sidewalls extending from a hub to a brake engaging portion of the wheel the sidewalls comprising: a radially inwardly positioned widened hub portiona radially outwardly disposed generally planar brake engaging portion, anda two part central portion extending between the hub portion and the brake engaging portion, wherein the central portion has a first section that curves inwardly from a widest point to a narrowest point and a second section that curves outwardly from the narrowest point to the brake engaging portion.

2. The assembly of claim 1, wherein the narrowest point is between approximately 50-60% the width of the widest point.

3. The assembly of claim 2, wherein the narrowest point is between approximately 50-55% the width of the widest point.

4. The assembly of claim 1, wherein the narrowest point is between approximately 80-90% the width of the brake engaging portion.

5. The assembly of claim 4, wherein the narrowest point is between approximately 85-90% the width of the widest point.

6. The disc wheel of claim 1 further comprising an end cap configured to fit over the hub, the end cap comprising: an outer oval shaped front wall defining a through bore configured to receive an axle;a radially outwardly facing sidewall extending from an edge of the front wall and tapering inward from a forward face to a rear face; andwherein said end cap defines a space behind the forward face to spinningly receive the hub.

7. An end cap for a disc wheel, the end cap comprising: an outer oval shaped front wall defining a through bore configured to receive an axle;a radially outwardly facing side wall extending from an edge of the front wall and tapering inward to define a forward face and a rear face; andwherein said end cap defines a space behind the forward face to spinningly receive a bicycle hub.

8. The end cap of claim 7 further comprising a nipple extending outwardly from the front wall.

9. The end cap of claim 7 wherein the end cap is constructed to spinningly receive the bicycle hub such that a longer axis of the outer oval shaped front wall is generally aligned with a direction of travel of a bicycle.

10. The end cap of claim 7 further comprising a rear wall constructed to engage a disc of a bicycle wheel such that the disc can rotate relative to the end cap.

11. The end cap of claim 10 wherein the disc further comprises a pair of upstanding walls constructed to extend between a hub and a rim.

12. The end cap of claim 11 wherein the pair of upstanding walls are positioned on generally radially opposite sides of the bicycle wheel and have generally mirror image cross-sections relative to a bisecting plane that is oriented generally perpendicular to an axis of rotation of the bicycle wheel.

13. The end cap of claim 11 wherein each of the pair of upstanding walls further comprises a radially inwardly positioned widened hub portion, a radially outwardly disposed generally planar brake engaging portion, and a central portion extending between the hub portion and the brake engaging portion, wherein the central portion has a first section that curves inwardly from a widest point to a narrowest point and a second section that curves outwardly from the narrowest point to the brake engaging portion.

14. A method of forming a bicycle disc wheel assembly comprising: forming a rim having a width and for supporting a tire;extending a pair of disc walls between generally opposite sides of the rim to a hub shell such that each disc wall has a lenticular cross-sectional shape that has a widest portion proximate the hub and a narrowest portion offset inwardly from the rim; andbonding a first end of each of the disc walls to the rim and a second end of each of the disc walls to a hub shell.

15. The method of claim 14 further comprising forming each of the pair of disc walls from a carbon fiber material.

16. The method of claim 14 further comprising forming a flange proximate the second end of at least one of the disc walls that extends in a direction generally transverse to the disc wall.

17. The method of claim 16 further comprising terminating the second end of the other disc wall without a flange.

18. The method of claim 17 further comprising forming a flange on the hub shell that extends radially outwardly from the hub shell and engages the second end of the other disc wall.

19. The method of claim 14 further comprising forming an end cap having an exterior surface with an airfoil shape.

20. The method of claim 19 further comprising forming an interior surface of the end cap to fixedly engage a non-rotating component of the disc wheel assembly for fixing a position of the end cap relative to a bicycle during use.