Self-locking fan shaft bearing

Abstract

A self-locking threaded bushing is provided for mounting a steel fan shaft in an aluminum support. The bushing is threaded so that it may be threaded into the aluminum structure. The bushing is provided with a bore corresponding to the shaft diameter such that a normal press fit is established when the shaft is initially pressed into the bushing. A reduced diameter portion of the bushing bore results in an interference fit between the shaft and the bore. Relief cuts in the bushing allow the bushing to expand in the vicinity of the reduced diameter portion as a result of interference from the shaft. The expansion of the bushing results in an interference fit between the threads of the bushing and those of the aluminum structure such that the bushing and shaft are essentially locked in place until such time as the shaft is extracted from the bushing.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:  
     
         1 . A self-locking bushing for mounting a fan shaft in a support structure having a threaded bore comprising: 
 a cylindrical main body portion having a threaded outer diameter wherein the bushing is threaded into the threaded bore of the support structure;    a first concentric bore in the main body portion for receiving the fan shaft, the first concentric bore having a diameter corresponding to an outer diameter of the fan shaft such that a normal press fit is established between the bushing and the fan shaft;    a second reduced diameter bore in the main body portion wherein an interference fit is established between the bushing and the fan shaft;    a plurality of relief cuts in the main body portion proximal to the reduced diameter bore wherein the main body portion of the bushing is allowed to expand in response to the interference fit between the bushing and the fan shaft so that an interference fit is established between the threaded outer diameter of the main body portion and the threaded bore of the support structure.    
     
     
         2 . A self-locking bushing for mounting a fan shaft in a support structure having a threaded bore as set forth in  claim 1  wherein the main body portion has four relief cuts equally spaced about the diameter thereof.  
     
     
         3 . A self-locking bushing for mounting a fan shaft in a support structure having a threaded bore as set forth in  claim 3  wherein the bushing further includes a flanged portion at a first end thereof.