1.  Field of the Invention
This invention generally relates to a bicycle disc brake hub.  More specifically, the present invention relates a bicycle disc brake hub with an integral rotor attachment portion or flange. 
2.  Background Information
Bicycling is becoming an increasingly popular form of recreation as well as a means of transportation.  Moreover, bicycling has become a very popular competitive sport.  Whether the bicycle is used for recreation, transportation or competition, the bicycle industry is constantly improving their components.  Recently, the braking systems for bicycles have included the use of disc brakes.  The use of disc brakes has resulted in modifications to the bicycle hub of the bicycle wheel so that a brake rotor can be mounted thereon. 
The most basic bicycle wheels have a hub, a plurality of spokes and an annular rim.  The hub is attached to a part of the frame of the bicycle for relative rotation.  The inner ends of the spokes are coupled to the hub and extend outwardly from the hub.  The annular rim is coupled to the outer ends of the spokes and has an outer portion for supporting a pneumatic tire thereon.  Typically, the spokes of the bicycle wheel are thin metal wire spokes.  The ends of the hub are provided with a flange that is used to couple the spokes to the hub.  In particular, holes are provided in the hub flanges.  The wire spokes are usually bent on their inner end and provided with an enlarged head or flange that is formed in the shape of a nail head.  The inner end is supported in one of the holes in one of the hub flanges.  The outer ends of the spokes typically are provided with threads for engaging spoke nipples, which secure the outer ends of the wire spokes to the rim.  In particular, the spoke nipples have flanges, which engage the interior surface of the rim. 
With a spoke constructed in this manner, the nipples are installed in nipple holes formed in the rim.  The spokes are inserted sideways through the holes in the hub flange until the enlarged head or flanges of the spokes engaging the areas surrounding the holes in the hub flange.  The male threads on the ends of the spokes are threaded into the female threads of the spoke nipples installed in the openings of the rim. 
When the hub is a disc brake hub, installation and/or replacement of the spokes can be difficult.  In the case of a disk brake hub, one end of the hub usually has a brake rotor attachment portion.  Often, the brake rotor attachment portion is a plurality of blind bores that receive bolts to directly mount the disc brake rotor to the end of the hub.  Thus, the disc brake rotor makes it difficult to insert the spokes in a sideways direction.  To overcome this problem, the spoke attachment portion adjacent the brake rotor attachment portion is often made to be larger in diameter than the brake rotor attachment portion.  This increases the weight of the disk brake hub as well as the cost to manufacture the disk brake hub. 
Moreover, hubs that have blind bores for mounting a disc brake rotor are time consuming to form and often become damaged.  When the blind bores become damaged, the entire hub must be replaced.  Thus, these prior hubs are expensive to manufacture and replace. 
In view of the above, there exists a need for a bicycle hub which overcomes the above mentioned problems in the prior art.  This invention addresses this need in the prior art as well as other needs, which will become apparent to those skilled in the art from this disclosure. 
One object of the present invention is to provide a bicycle hub with an integrated brake rotor attachment portion disposed adjacent the first spoke attachment portion such spokes can easily be installed into first spoke holes of the first spoke attachment portion. 
Another object of the present invention is to provide a bicycle hub with an integrated brake rotor attachment portion disposed adjacent the first spoke attachment portion that is relatively lightweight. 
Another object of the present invention is to provide a bicycle hub with an integrated brake rotor attachment portion disposed adjacent the first spoke attachment portion that is relatively inexpensive to manufacture. 
The foregoing objects can be attained by providing a bicycle disc brake hub comprising a hub axle, a hub shell, a first spoke attachment portion, a second spoke attachment portion and a brake rotor attachment portion.  The hub axle has a center axis extending in an axial direction between a first axle end and a second axle end.  The hub shell has an interior passageway extending between first and second hub shell ends with the hub axle being rotatably supported in the interior passageway.  The first spoke attachment portion has a plurality of first spoke holes extending axially between the first and second axially facing surfaces.  The first spoke holes have center axes spaced a first radial distance from the center axis of the hub axle.  The first spoke attachment portion is disposed at the first hub shell end with the second axially facing surface facing towards the second hub shell end.  The second spoke attachment portion has a plurality of second spoke holes.  The second spoke attachment portion is disposed at the second hub shell end.  The brake rotor attachment portion has a plurality of axially extending rotor mounting holes with predetermined diameters and center axes spaced a second radial distance from the center axis of the hub axle.  The brake rotor attachment portion is disposed adjacent the first spoke attachment portion with the first axially facing surface facing towards the brake rotor attachment portion.  The first spoke attachment portion and the brake rotor attachment portion are arranged relative to each other to attach spokes to the first spoke holes through the rotor mounting holes of the brake rotor attachment portion. 
Preferably, the first spoke holes are individually viewable in the axial direction from a location looking axially towards the brake rotor attachment portion.  The first axially facing surface of the first spoke attachment portion and the first radial distance of the first spoke holes are less than the second radial distance plus half of the predetermined diameter of one of the rotor mounting holes. 
The foregoing objects can also be attained by providing a bicycle disc brake hub comprising a hub axle, a hub shell, a first spoke attachment portion, a second spoke attachment portion and a brake rotor attachment portion.  The hub axle has a center axis extending in an axial direction between a first axle end and a second axle end.  The hub shell has an interior passageway extending between first and second hub shell ends with the hub axle being rotatably supported in the interior passageway.  The first spoke attachment portion has a plurality of first spoke holes extending axially between the first and second axially facing surfaces.  The first spoke attachment portion being disposed at the first hub shell end with the second axially facing surface facing towards the second hub shell end.  The second spoke attachment portion has a plurality of second spoke holes, the second spoke attachment portion being disposed at the second hub shell end.  The brake rotor attachment portion has a plurality of axially extending rotor mounting holes and an outer peripheral surface that lies within an imaginary circle circumscribing the outer peripheral surface.  The brake rotor attachment portion is disposed adjacent the first spoke attachment portion with the first axially facing surface facing towards the brake rotor attachment portion.  The first spoke holes is located radially inward of the imaginary circle circumscribing the outer peripheral surface of the brake rotor attachment portion. 
The foregoing objects can further be attained by providing a bicycle disc brake hub comprising a hub axle, a hub shell, a first spoke attachment portion, a second spoke attachment portion and a brake rotor attachment portion.  The hub axle has a center axis extending in an axial direction between a first axle end and a second axle end.  The hub shell has an interior passageway extending between first and second hub shell ends with the hub axle being rotatably supported in the interior passageway.  The first spoke attachment portion has a plurality of first spoke holes extending axially between the first and second axially facing surfaces.  The first spoke attachment portion is disposed at the first hub shell end with the second axially facing surface facing towards the second hub shell end.  The second spoke attachment portion has a plurality of second spoke holes.  The second spoke attachment portion being disposed at the second hub shell end.  The brake rotor attachment portion has a plurality of axially extending rotor mounting holes.  The brake rotor attachment portion is disposed adjacent the first spoke attachment portion with the first axially facing surface facing towards the brake rotor attachment portion.  The brake rotor attachment portion and the first spoke attachment portion have maximum outer diameters with the maximum outer diameter of the first spoke attachment portion being no greater than the maximum outer diameter of the brake rotor attachment portion. 
These and other objects, features, aspects and advantages of the present invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses preferred embodiments of the present invention.