Method for producing exterior component of assembled camshaft

Abstract

Chillers ( 4 ) rapidly remove heat from a coupling of cam pieces ( 6 ) immediately after molten metal is injected, so as to make the coupling of cam pieces ( 6 ) chilled (be a white cast iron). As a result, tensile strength and shear strength of the coupling of cam pieces ( 6 ) decreases while the coupling of cam pieces ( 6 ) becomes harder. Cam piece original shapes and notches are alternately formed in the coupling of cam pieces ( 6 ). The notch of the coupling of cam pieces ( 6 ) which is being held by a holder is hit by a breaking tool. Then, the coupling of cam pieces ( 6 ) with low tensile strength breaks at the notch which is the vulnerable portion so that an individual cam piece is obtained.

1 . A method for producing an exterior component of an assembled camshaft, comprising: 
 a casting step for casting a coupling of exterior components which has a shaft fit hole, and in which plural exterior component original shapes between which vulnerable portions are inserted are coupled; and    a dividing step for breaking the coupling of exterior components at one of the vulnerable portions to obtain the exterior component.    
   
   
       2 . A method for producing an exterior component of an assembled camshaft as claimed in  claim 1 , wherein 
 in the casting step, the coupling of exterior components is chilled.    
   
   
       3 . A method for producing an exterior component of an assembled camshaft as claimed in  claim 1 , wherein 
 in the casting step, the coupling of exterior components is cast by plural chillers which have, in inner surfaces, original shape cast portions of cam pieces which are the exterior components, and cast portions of notches which are the vulnerable portions.    
   
   
       4 . A method for producing an exterior component of an assembled camshaft as claimed in  claim 2 , wherein 
 the coupling of exterior components is chilled by chillers which rapidly remove heat immediately after molten metal is injected.    
   
   
       5 . A method for producing an exterior component of an assembled camshaft as claimed in  claim 1 , wherein 
 in the dividing step, the coupling of exterior components which is held by a holder is hit and broken with a breaking tool at a notch which is a vulnerable portion in order that a cam piece which is the exterior component is obtained.    
   
   
       6 . A method for producing an exterior component of an assembled camshaft as claimed in  claim 1 , comprising 
 a processing step for applying as needed at least one of a rough process to a cam surface and a cutting process to a shaft hole after the dividing step.