Patent ID: 8677850

Claim:
A gear spindle, comprising: a shaft having a first gear cavity at a first end; an oil delivery path for delivering oil to the first gear cavity; an oil return path for carrying oil away from the first gear cavity; a first seal assembly associated with the first end of the shaft, the first seal assembly including: a first seal component with an outwardly facing part spherical surface, a second seal component with an inwardly facing part spherical surface that is spaced apart from the outwardly facing part spherical surface of the first seal component, a third seal component between the first seal component and the second seal component, the third seal component having both an inwardly facing part spherical surface and an outwardly facing part spherical surface, the inwardly facing part spherical surface of the third seal component in surface to surface contact with the outwardly facing part spherical surface of the first seal component to form a first sealing interface, the outwardly facing part spherical surface of the third sealing component in surface to surface contact with the inwardly facing part spherical surface of the second seal component to form a second sealing interface, the first sealing interface having one side in fluid communication with the first gear cavity and an opposite side in fluid communication with a secondary cavity for limiting leakage of oil from the first gear cavity into the secondary cavity, a fluid delivery path for delivering pressurized air to the secondary cavity for countering gear cavity pressure across the first sealing interface; the second sealing interface for holding compressed air in the secondary cavity.