Method for Making a Bicycle Hub

Abstract

A method of making a rear hub of a bicycle comprises: swaging a straight pipe into an hour-glass-shaped semi product, extruding the semi-product to form a hub flange, punching a plurality of holes in the hub flange of the semi-product, binding an edge of an end of the semi-product, necking down the edge-bound end of the semi-product, trimming the semi-product, and chamfering the holes of the semi-product to form a chamfer structure on an edge of the respective holes.

1 . A method for making a rear hub of a bicycle comprising the following steps: 
 swaging a straight pipe into an hour-glass-shaped semi product;    extruding the semi-product to form a hub flange at either end of the semi-product;    punching a plurality of holes in the hub flange of the semi-product, and the holes are annularly arranged;    binding an edge of an end of the semi-product;    necking down the edge-bound end of the semi-product;    trimming both ends of the semi-product to a predetermined value; and    chamfering the holes of the semi-product to form a chamfer structure on an edge of the respective holes.    
   
   
       2 . The method for making a rear hub of a bicycle as claimed in  claim 1 , wherein the chamfering step is allowed to be carried out before the step of necking down the edge-bound end of the semi-product.  
   
   
       3 . The method for making a rear hub of a bicycle as claimed in  claim 1 , wherein the trimming step is allowed to be carried out before the step of necking down the edge-bound end of the semi-product.  
   
   
       4 . The method for making a rear hub of a bicycle as claimed in  claim 1 , wherein the chamfering step is allowed to be carried out before the trimming step.  
   
   
       5 . The method for making a rear hub of a bicycle as claimed in  claim 1 , wherein the steps of necking, trimming, chamfering and edge-binding are allowed to be carried out in any order.