Positioning Structure for a Bicycle Hub and Method for Making the Same

Abstract

A bicycle hub comprises a hub shell each end of which is formed with a receiving portion. The outer surface of the rub shell is clamped by a positioning machine, and the inner surface of each receiving portion is axially pressed to form at least three positioning structures. The positioning structures are formed by the following steps: A. bicycle hub clamping step; B. bicycle hub press forming step; and C. bicycle hub loading step. By such arrangements, the positioning structures of the bicycle hub can be obtained by the quick press forming without affecting the structure strength.

1 . A positioning structure for a bicycle hub comprising a bicycle hub with a hub shell; each end of the hub shell is axially formed with a receiving portion, and each receiving portion is pressed to form at least three positioning structures for positioning a bearing. 
   
   
       2 . The positioning structure for a bicycle hub as claimed in  claim 1 , wherein the hub shell of the bicycle hub is a hollow cylinder. 
   
   
       3 . The positioning structure for a bicycle hub as claimed in  claim 1 , wherein the receiving portion of the bicycle hub is a hollow cylinder. 
   
   
       4 . The positioning structure for a bicycle hub as claimed in  claim 1 , wherein the positioning structures for the bicycle hub are semicircular flanges. 
   
   
       5 . A method of making the positioning structure for a bicycle hub comprising steps of:
 A. bicycle hub clamping step: clamping an outer surface of a bicycle hub by a positioning machine firstly;   B. bicycle hub press forming step: after the bicycle hub is clamped by the positioning machine, pressing an inner surface of a receiving portion which is axially formed at each end of the bicycle hub with a punch to form at least three positioning structures shaped correspondingly to three ribs of the punch by using points as targets; and   C. bicycle hub loading step: after the inner surface of each receiving portion is pressed by the punch to form at least three positioning structures, placing a bearing in each receiving portion of the bicycle hub, and the bearing is positioned by the receiving portion.   
   
   
       6 . The method of making the positioning structure for a bicycle hub as claimed in  claim 5 , wherein the positioning machine of step A includes an upper clamping arm and a lower clamping arm, and the bicycle hub is clamped by the upper clamping arm and the lower clamping arm. 
   
   
       7 . The method of making the positioning structure for a bicycle hub as claimed in  claim 6 , wherein the punch of step B includes a punching member, one end of the punching member is formed with a punching head, and on a periphery of the punching head are formed at least three annularly-arranged parallel punching ribs, the punch utilizes the punching head of the punching member to punch an inner surface of each receiving portion by inserting it into an open end of each receiving portion, so as to form at least three positioning structures on each receiving portion of the bicycle hub that are shaped correspondingly to the punching ribs of the punching head.