Oil pump driving structure of automatic transmission

Abstract

There is provided an oil pump driving structure of an automatic transmission which can prevent slack of a chain, which is looped over a drive sprocket on a main shaft and a driven sprocket of an oil pump, and resulting poor engagement of the chain and the driven sprocket by a simple construction. A chain guide is projected integrally from an end face of a housing cover attached to an opening of a switching unit housing in a transmission case and is located in the vicinity of the driven sprocket. The chain guide guides a slacked side of the chain through a path closer to a tensioned side of the chain. As a result, even if the accuracy of the center distance between a drive sprocket and the driven sprocket is not improved, vibration of the chain can be suppressed to improve quietness.

1 . An oil pump driving structure of an automatic transmission, comprising: 
 an oil pump disposed apart from a main shaft of the automatic transmission;    a chain looped over a drive sprocket provided on the main shaft and a driven sprocket of said oil pump, for transmitting revolutions from the drive sprocket to the driven sprocket; and    a chain guide that guides a slacked side of said chain through a path that reduces an amount of slack thereof.    
   
   
       2 . An oil pump driving structure of an automatic transmission according to  claim 1 , wherein said chain guide is provided on a transmission case side of the slacked side of said chain and in vicinity of the slacked side of said chain.  
   
   
       3 . An oil pump driving structure of an automatic transmission according to  claim 2 , further including: 
 a transmission case for the automatic transmission comprises a switching unit housing that houses a forward/backward switching unit, and a housing cover attached to an opening of the switching unit housing,    wherein said chain guide is projected integrally from the housing cover.    
   
   
       4 . An oil pump driving structure of an automatic transmission according to  claim 1 , wherein said chain guide is provided in vicinity of the driven sprocket.  
   
   
       5 . An oil pump driving structure of an automatic transmission according to  claim 1 , wherein said chain guide guides the slacked side of said chain through a path closer to a tensioned side of said chain.