Patent ID: 7316553
Filing Date: 2008-01-08
Classification: B29C,F15B,H02K

Abstract:
1. An injection unit for an injection molding machine, the injection unit comprising: a hollow electric motor, a first cylinder wall of a first hydraulic cylinder joined to a rotor of said hollow electric motor, a second cylinder wall of a second hydraulic cylinder connected to a stationary portion of said hollow electric motor, a piston slidable along interior surfaces of said first cylinder wall and said second cylinder wall, a first end portion of said piston engaging said first cylinder wall and a second end portion of said piston engaging said second cylinder wall, rotating structure attached to said rotor and configured to rotate said piston, said rotating structure being configured such that said piston slides along said first cylinder wall and said second cylinder wall, structure configured to provide hydraulic fluid to drive said piston along said first cylinder wall and said second cylinder wall, and structure configured to attach an injection screw to said piston, whereby said piston slides lengthwise along said first cylinder wall and said second cylinder wall when hydraulically driven and is rotated by said rotating structure when said hollow electric motor is activated to rotate said rotor.