Single piece hub with integral upper and lower female cones and method for making the same

Abstract

To simplify fabrication of an integral hub piece, the opening between the upper and lower female cones in this hub has sufficient width or radial dimension to allow access to both cones from one side of the hub with the cutting tool. A cutting tool is used which has a width smaller than the opening between the cones. Preferably, the tool has a width which is about equal to or smaller than an angular dimension through this opening which is defined by extending surfaces of the upper and lower female cones. If this limitation is satisfied, both cones can be created with a single machine set up operating from one side of the integrated hub. Preferably the tool should only move orthogonal or parallel to the cutting tools rotational center axis.

What is claimed is:  
     
         1 . A dual conical fluid dynamic bearing comprising an integral male cone/shaft element, an integral male cone/bore element, an integral single piece hub having first and second female cones defined therein and joined by a central opening, said male cone/shaft element and said male cone/bore element being joined through said central opening and supported by a fluid for relative rotation.  
     
     
         2 . A fluid dynamic bearing as in  claim 1  wherein said male cone/shaft element comprises a conical element and a shaft extending axially away from a narrow end of said cone.  
     
     
         3 . A fluid dynamic bearing as in  claim 2  wherein said male cone/bore element comprises a cone with a shaft extending axially away from a wide end of said cone and further having a bore extending through said cone and said shaft, said shaft of said integral cone/shaft element fitted into said bore of said cone/bore element to accurately position said cone of said cone/shaft element relative to said cone of said cone/bore element.  
     
     
         4 . A method of forming an integral, one piece hub for a dual conical fluid dynamic bearing comprising: 
 defining a center hole having an opening dimensioned to accommodate a narrow end of each cone of a dual conical bearing, as well as passage of a tool for cutting surfaces of each of a pair of female cones in said hub defining each of a pair of female cones in said integral hub utilizing the tool which has a width dimension less than or equal to the angled dimension through the central opening so that each of said pair of female cones may be cut from one side of said hub.    
     
     
         5 . A method as claimed in  claim 4  in which the hole is dimensioned to accommodate the tool passing from one of the cones to the other of the cones without substantially changing the angle of the tool relative to a central axis of the integral hub.  
     
     
         6 . A method as claimed in  claim 5  wherein a maximum dimension for the tool is defined by drawing a line over a projected finished surface for each of said cones through the hole through which the tool passes, the distance between the lines establishing a maximum width of the tool.  
     
     
         7 . A method as claimed in  claim 6  wherein the distance between the lines is established at the center hole of the integrated hub.  
     
     
         8 . A dual conical fluid dynamic bearing comprising a hub having first and second female cones defined therein and joined by a central opening, the central opening being a sufficient width to accommodate means for serially cutting the first and second cones without modification of setup of said hub relative to said cutting means.  
     
     
         9 . A fluid dynamic bearing as in  claim 8  wherein said means for cutting cuts said conical surfaces serially.