Transfer pump for injection of fuel at high pressure

Abstract

A transfer pump for the injection of fuel under high pressure of the type comprising a piston ( 10 ) providing the hydraulic liquid to a deformable bellows ( 14 ), the deformations of said bellows ( 14 ) in a cylindrical chamber ( 20 ) filled with fuel giving rise to a high pressure pumping effect of said fuel; a cam ( 5 ) provided with lugs ( 6 ) carried by a drive shaft ( 1 ), is characterized in that the oil portion of the pump comprises: the portion of the drive shaft ( 1 ) bearing the cam ( 5 ); the cam ( 5 ) and its lugs ( 6 ); the roller ( 7 ) with its shaft ( 8 ) and its roller bearing ( 9 ) carried by a bearing member ( 12 ), by which roller the cam( 5 ) bears on the piston ( 10 ); as well as the upper portion of said piston ( 10 ); such that all the mechanical drive portion and angle change are bathed in the oil of the oil portion.

1 . Transfer pump for injection of high pressure fuel of the type comprising a piston ( 10 ) supplying hydraulic liquid to a deformable bellows ( 14 ), the deformations of said bellows ( 14 ) in a cylindrical chamber ( 20 ) filled with fuel, giving rise to a pumping effect at high pressure of said fuel; a cam ( 5 ) provided with lugs ( 6 ) carried by a drive shaft ( 1 ), characterized by the fact that the oil portion of the pump comprises: the portion of the drive shaft ( 1 ) bearing the cam ( 5 ); the cam ( 5 ) and its lugs ( 6 ); the roller ( 7 ) with its shaft ( 8 ) and its roller bearing ( 9 ) carried by a bearing member ( 12 ), by which roller the cam ( 5 ) bears on the piston ( 10 ); as well as the upper portion of said piston ( 10 ): such that all the mechanical drive portion and the angle change bathe in the oil of the oil portion. 
   
   
       2 . Transfer pump according to  claim 1 , in which the sealing between the oil portion and the drive shaft ( 1 ) is ensured by a simple joint with loops ( 30 ). 
   
   
       3 . Transfer pump according to  claim 1 , in which the chamber ( 21 ) of the housing ( 3 ) in which the cam ( 5 ) works is connected to a volume compensator ( 26 ). 
   
   
       4 . Transfer pump according to  claim 3 , in which a second volume compensator ( 27 ) is connected to the bore ( 22 ) in which operate the roller ( 7 ), the bearing member ( 12 ) and the upper portion of the piston ( 10 ). 
   
   
       5 . Pump according to  claim 4 , in which the piston ( 10 ) comprises an internal bore ( 10   a ) communicating with said bore ( 22 ) by an opening ( 24 ) and comprises a non-return valve ( 28 ); such that the volume of oil placed under pressure is small. 
   
   
       6 . Pump according to  claim 5 , in which the piston ( 10 ) sides in a sleeve ( 13 ) provided at its base with a disc ( 17 ) having a bore ( 19 ) in which slides a finger ( 18 ) carried by a member ( 15 ) fixed to the base of the bellows ( 14 ); so as to ensure the guidance of said bellows ( 14 ) during its successive deformations. 
   
   
       7 . Pump according to  claim 1 , in which the shaft drive mechanism for the shaft ( 1 ) is a freewheel mechanism.