Hybrid propeller shaft made of metal and composite material and method of manufacturing the same

Abstract

The propeller shaft comprises a transmission shaft 10 consisting of a hollow metal tube 11 with excellent torque transmissibility and a composite material prepregs 12 having higher specific stiffness than a metal material and stacked to the inner surface of the metal tube, and metal yokes 40 mounted on both ends of the transmission shaft and assembled with other devices. The composite material prepregs is co-cure bonded while applying an axial compressive preload to the transmission shaft and creating a vacuum in a space between a vacuum bag inserted in the transmission shaft and the composite material prepregs of the transmission shaft. Teeth 43 or embossments 44 , and adhesive-retaining grooves 45 are formed on inner surfaces of the metal yokes, so the transmission shaft is desirably compression-fitted into the metal yokes. Accordingly, the propeller shaft has advantages of securing improved impact, abrasion, and water resistance.

1 - 18 . (canceled)  
   
   
       19 . A propeller shaft comprising a transmission shaft having a metal tube and a composite material prepregs stacked to an inner surface of the metal tube, and yokes mounted on both ends of the transmission shaft, wherein the composite material prepregs are co-cure bonded while maintaining axial compression on the metal tube and pressure on the surface of the composite material prepregs, bores are formed in the yokes to allow the yokes to be fitted around the transmission shaft, and teeth or embossments are formed on inner surfaces of the bores.  
   
   
       20 . The propeller shaft as set forth in  claim 19 , wherein a protective layer is provided on the composite material prepregs stacked to the inner surface of the metal tube to improve a damping capacity of the propeller shaft.  
   
   
       21 . The propeller shaft as set forth in  claim 19 , wherein the composite material prepregs comprises a plurality of carbon fiber composite material prepregs layered in such a way that the stacking angle of one carbon fiber composite material prepreg is transverse or fabric, while those of an adjacent carbon fiber composite prepregs are close to axial direction.  
   
   
       22 . The propeller shaft as set forth in  claim 21 , wherein the composite material prepregs comprises a carbon fiber polymeric matrix and a glass fiber polymeric matrix composite material, the latter has the role to prevent the metal tube from galvanic corroding and to minimize residual thermal stress of the metal tube.  
   
   
       23 . The propeller shaft as set forth in  claim 19 , wherein each bore of the yokes includes a guide bore part and a fitting bore part in conjunction with the guide bore part, the guide bore part having an inner diameter slightly larger than an outer diameter of the transmission shaft to guide the transmission shaft when the yokes are fitted into the transmission shaft so that a central axis of the transmission shaft corresponds to those of the yokes and the teeth or embossments are formed on an inner surface of the fitting bore part.  
   
   
       24 . The propeller shaft as set forth in  claim 23 , wherein the inner diameter of the guide bore part is gradually decreased in a direction toward a center of an inside end of each of the metal yokes.  
   
   
       25 . The propeller shaft as set forth in  claim 23 , wherein a plurality of adhesive-retaining grooves are formed between the embossments on the inner surface of the fitting bore part and an adhesive is filled in the adhesive-receiving grooves to attach the yokes to the transmission shaft.