Gear spindle and oil seal used therein

A gear spindle including an outer-cylinder portion with a gear portion carved on an inner peripheral surface thereof and an inner cylinder portion with a gear portion carved on an outer peripheral surface thereof, the gear portions meshing with each other, the gear spindle being configured to be used in a rolling mill and to rotate with shaft axes of the outer cylinder portion and the inner cylinder portion being slanted relative to each other at a slant angle θ, wherein

• the gear portion of the outer cylinder portion is formed integrally with the inner peripheral surface thereof, while the gear portion of the inner cylinder portion is formed integrally with the outer peripheral surface thereof, and
• an oil seal configured to seal a lubricating oil for the gear portions includes
• a seal body interposed in a peripheral gap between the inner peripheral surface of the outer cylinder portion and the outer peripheral surface of the inner cylinder portion, and
• a seal attachment member configured to tighten securely and fix the seal body to the outer peripheral surface of the inner cylinder portion such that the seal body is expandable in the peripheral gap between the inner peripheral surface of the outer cylinder portion and the outer peripheral surface of the inner cylinder portion,
• the seal body has an outer ring portion in surface contact with the inner peripheral surface of the outer cylinder portion, an inner ring portion in surface contact with the outer peripheral surface of the inner cylinder portion, and an intermediate ring portion connecting the outer ring portion and the inner ring portion to each other, the intermediate ring portion defining a recess facing a lubricating oil side, the recess receiving pressure of the lubricating oil,
• the seal attachment member is placed on a side having the lubricating oil,
• on the lubricating oil side, an annular groove is formed on the outer peripheral surface of the inner cylinder portion, the annular groove being configured such that an annular protruding portion formed on an inner peripheral surface of the inner ring portion is fitted into the annular groove to position the seal body in an axial direction, and
• the outer ring portion is fixed in the axial direction,
• wherein the outer ring portion is formed to extend from an end portion of the intermediate ring portion to both sides in the axial direction.