Patent Application
20100260544
The present invention relates to a bicycle rear hub and more particularly, to an engaging portion on a bicycle rear hub rear wheel hub so as to be connected with a CAMPAGNOLO sprocket set.
A conventional derailleur system for bicycle generally includes at least one chain ring connected with the crank, a sprocket set connected to one end of the rear wheel hub, and a chain which transfers the driving force from the chain ring to one of the sprockets of the sprocket set. Generally, the sprocket set includes 5 to 10 sprockets of different number of teeth and the shifting mechanism of the derailleur system shifts the chain from one sprocket to another so as to obtain desired speed.
There are two main brand names for the connection tubes of the rear wheel hubs, which are SHIMANO and CAMPAGNOLO, the difference between the connection tubes of the two brands is the engaging portion on the rear wheel hub.
As shown in
As shown in
It is noted that, for the connection tube 84 of CAMPAGNOLO, each rib 85 has a recess 851 whose two insides are in contact with the two outsides of the protrusion 83. However, the direction of rotation of the sprocket set 80 is fixed so that only the inside “A” of the recess 851 actually transfers the force, and the other inside “B” does not provide such function.
The requirement for having the precision of the recess 851 is high so that the protrusion 83 can properly engage with the recess 851 and successfully transfer force to the rear wheel. The assemblers have to check carefully for the engagement of the protrusions 83 and the recesses 851 and this increases the time required and the cost of labor cost. Besides, the inside “B” does not have the same function as the inside “A”, the material and manufacturing processes to the inside “B” become a waste.
The present invention intends to provide a connection tube of a rear wheel hub wherein multiple driving ribs and one positioning rib located on the engaging portion of the connection tube. Each driving rib has a driving surface and an inclined surface on two sides thereof, only the driving surface contacts the engaging rib in the engaging hole of the sprockets.
The present invention relates to a connection tube of bicycle rear wheel hub and the connection tube includes a connection portion extending axially from a first end thereof so as to be connected with the bicycle rear wheel hub, and an engaging portion extends axially from a second end of the connection tube so as to extend from an end of the rear wheel hub. The engaging portion is a hollow tube and four driving ribs extend radially from an outer periphery of the engaging portion and each driving rib includes a driving surface and an inclined surface on two sides thereof. The driving surface is perpendicular to the outer periphery of the engaging portion. A positioning rib extends radially from an outer periphery of the engaging portion and is located axially on the engaging portion. The positioning rib is located between two driving ribs.
The primary object of the present invention is to provide a connection tube on the rear wheel hub and four driving ribs and one positioning rib located on the outer periphery of the connection tube. Each of the driving ribs includes a driving surface and an inclined surface on two sides thereof and only the driving surface transfers the force from the sprocket set to the rear wheel hub.
Another object of the present invention is to provide a connection tube on the rear wheel hub wherein the manufacturing cost of the connection tube is significantly reduced because only the driving surface contacts the engaging rib of the sprocket set.
The present invention will become more obvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, a preferred embodiment in accordance with the present invention.
Referring to
A sprocket set 40 is composed of multiple sprockets 41 and each sprocket 41 has an engaging hole 42 with which the engaging portion 20 is engaged. Four engaging ribs 43 extend inward from the inner periphery of the engaging hole 42 so as to be engaged with the driving ribs 21 of the engaging portion 20. An assembly rib 44 extends inward from the inner periphery of the engaging hole 42 and located between the adjacent two engaging ribs 43.
When mounting the sprocket set 40 to the engaging portion 20 of the rear wheel hub 50, the diving ribs 21 are located between the engaging ribs 43 of the sprocket set 40. The driving surfaces 211 of each driving rib 21 contacts the side of the engaging rib 43 corresponding thereto. The positioning rib 30 is engaged with the assembly rib 44, wherein the assembly rib 44 is a stepped rib and includes an engaging step 441 with which the second step 32 of the positioning rib 30 is in contact. The crown surface 213 has a width between 2 mm to 4 mm, which is smaller than that of SHIMANO. The height of the driving ribs 21 is larger than that of SHIMANO.
As shown in
It requires a longer assembly time for engaging the connection tube as shown in
While we have shown and described the embodiment in accordance with the present invention, it should be clear to those skilled in the art that further embodiments may be made without departing from the scope of the present invention.
