Patent ID: 6126401
Filing Date: 2000-10-03
Classification: F04B,F15B

Abstract:
A hybrid electric hydraulic drive system, comprising:a first hydraulic cylinder having a left chamber and a right chamber separated by a piston;a second hydraulic cylinder having a sole fluid chamber for receiving hydraulic fluid, said second hydraulic cylinder enclosing a second piston, said second hydraulic cylinder being substantially equal in length to said first hydraulic cylinder and being attached rigidly in parallel thereto;a pump fluidly connected to said left chamber by a first fluid passage said fluidly connected to said right chamber by a second fluid passage;a third fluid passage directly connected to said first hydraulic cylinder and to said sole fluid chamber of said second hydraulic cylinder;a controller;an electric motor for driving said pump, said electric motor being electrically connected to said controller;a first rod connected to said piston;a second rod connected to said second piston;an encoder, said encoder being electrically connected to said controller;a connecting element connecting said first rod and said second rod, so said first rod and said second rod move in unison; andwherein said sole chamber has a volume equal to the volume of said first rod, said first rod displacing fluid in said right chamber of said first hydraulic cylinder.