Steering wheel

Abstract

A steering wheel incorporates a hard portion bonded to the overall circumference in the cross-sectional circumferential direction of a ring portion and a soft portion molded to cover the core metal of the ring portion and softer than the hard portion, the hard portion and the soft portion being disposed in the planar circumferential direction of the ring portion. An extended portion extending from the soft portion is disposed on the surface of the core metal of the ring portion at a position on the inside of the hard portion. The steering wheel enables the hard portion and the soft portion to be formed around the core metal of the ring portion by collective injection molding. The core metal of the ring portion has an inverted U-shape cross sectional shape and made of die-cast metal formed by die-casting. When the two hard portions having different volumes are molded, time periods required to complete injection of a material for molding into each cavity of the mold for molding each hard portion are made to be substantially the same to mold the hard portions. A coating layer can be provided for the surface of the hard portion. A leather is bonded to the surface of the soft portion. Support surfaces for supporting the inner surfaces of the ends of the leather and projection projecting into the inner surface of the soft portion are formed at the end of the hard portion. The coating layer is as well as applied to the outer surface of the support portion so as to bond the soft layer and the leather to the hard portion.

What is claimed is:  
     
         1 . A steering wheel comprising: 
 a core metal of a ring portion thereof;    a soft portion formed by molding to cover said core metal of said ring portion;    an extended portion integrally extended from said soft portion to surround said core metal of said ring portion; and    a hard portion covering said extended portion, and being harder than said soft portion.    
     
     
         2 . A steering wheel according to  claim 1 , wherein said hard portion and said extended portion are molded simultaneously and made of the same material.  
     
     
         3 . A steering wheel according to  claim 1 , wherein said hard portion incorporates an upper split member having an inverted U-shape cross sectional shape and a lower split member having a U-shape cross sectional shape.  
     
     
         4 . A steering wheel according to  claim 1 , wherein said soft portion and said extended portion cover an overall body of said core metal of said ring portion.  
     
     
         5 . A steering wheel according to  claim 1 , wherein said extended portion is thinner than said soft portion by a thickness of said hard portion.  
     
     
         6 . A steering wheel according to  claim 1 , further comprising: 
 a coating layer applied to the surface of said hard portion; and    a leather disposed on the surface of said soft portion, wherein ends of said leather are supported by support portions formed at the ends of said hard portion so as to be secured to said hard portion, and    said coating layer is as well as applied to the outer surface of said support portion, and said soft portion and said leather are bonded to said hard portion through said coating layer.    
     
     
         7 . A steering wheel according to  claim 6 , wherein each of said support portions at the ends of said hard portion comprises: 
 a support surface for supporting the inner surface of said leather; and    a tapered portion having a narrowed outer shape formed to project over said support surface to be disposed apart from the inner surface of said leather.    
     
     
         8 . A steering wheel according to  claim 6 , further comprising an adhesive layer applied to the surface of said soft portion, and said leather being bonded to the surface of said soft portion through said adhesive layer.  
     
     
         9 . A steering wheel according to  claim 8 , wherein said leather is bonded to said support portion through said adhesive layer and said coating layer.  
     
     
         10 . A steering wheel according to  claim 6 , further comprising: 
 a decorative layer disposed between the surface of said hard portion and said coating layer and incorporating a printed layer and a primer layer disposed between the surface of said hard portion and said printed layer to enhance adhesion between said hard portion and said printed layer, wherein    also said decorative layer and said coating layer are applied to the outer surface of said support portion, and said soft portion and said leather are bonded to said hard portion through said decorative layer and said coating layer.    
     
     
         11 . A steering wheel according to  claim 10 , wherein said decorative layer and said coating layer are as well as applied to a portion between said core metal of said ring portion and said soft portion.  
     
     
         12 . A steering wheel comprising: 
 a core metal of a ring portion;    a hard portion disposed around said core metal of said ring portion; and    a soft portion disposed around said core metal of said ring portion and softer than said hard portion,    wherein said hard portion and said soft portion are disposed in a planar circumferential direction of said core metal of said ring portion, and said core metal of said ring portion being is of die-cast metal.    
     
     
         13 . A steering wheel according to  claim 12 , wherein said die-cast metal has a coefficient of thermal expansion of 20×10 −6 /° C. or greater.  
     
     
         14 . A steering wheel according to  claim 12 , wherein said die-cast metal is one of an aluminum alloy and a magnesium alloy.  
     
     
         15 . A steering wheel according to  claim 12 , wherein said die-cast metal has a thermal conductivity of 0.30 cal·cm −1 ·s −1 ° C. or greater at 20° C.  
     
     
         16 . A steering wheel according to  claim 12 , further comprising a decorative layer disposed on the surface of said hard portion.  
     
     
         17 . A steering wheel according to  claim 16 , wherein said decorative layer incorporates a printed layer, a primer layer disposed between the surface of said hard portion and said printed layer to enhance adhesion between said hard portion and said printed layer and a transparent glossy layer arranged to protect said printed layer and formed by coating the surface of said printed layer.  
     
     
         18 . A steering wheel according to  claim 16 , further comprising: 
 a coating layer applied to the surface of said decorative layer; and    a leather disposed on the surface of said soft portion,    wherein said decorative layer incorporates a printed layer and a primer layer disposed between the surface of said hard portion and said printed layer to enhance adhesion between said hard portion and said printed layer,    ends of said leather are supported by support portions formed at the ends of said hard portion and secured to said hard portion, and    said decorative layer and said coating layer are as well as applied to the outer surface of each of said support portions, and said soft portion and said leather are bonded to said hard portion through said decorative layer and said coating layer.    
     
     
         19 . A steering wheel according to  claim 18 , wherein said decorative layer and said coating layer are as well as applied to a portion between said core metal of said ring portion and said soft portion.