Patent ID: 7121555

Claim:
A crawler-track connection structure comprising: a pin ( 8 ) to be inserted through superposed end portions of links ( 5 ) and ( 5 ); and a seal assembly (S) externally fitted on said pin ( 8 ) for preventing overflow of a lubricant to the outside, the lubricant being supplied to an outer peripheral side of said pin ( 8 ), wherein one of said links ( 5 ) and ( 5 ) is immobilized on said pin ( 8 ); the other one of said links ( 5 ) and ( 5 ) is supported on said pin ( 8 ) to be rotatable thereon; and said seal assembly comprises a load seal ring ( 2 ) disposed between radial-direction walls (W) and (W) opposing each other along an axial direction and having an axial-direction length at an inner-peripheral side less than a distance between said radial direction walls, a first seal ring ( 1 ) comprising a lip portion ( 23 ) press-engaged with one of said radial-direction walls (W) and (W) according to a pressure exerted from said load seal ring ( 2 ), a second seal ring ( 1 ) comprising a lip portion ( 23 ) press-engaged with the other one of said radial-direction wails (W) and (W) according to a pressure exerted from said load seal ring ( 2 ), one of said seal rings ( 1 ) and ( 1 ) comprises a controller body ( 32 ) for controlling the displacement of said load seal ring ( 2 ) in a first periphery direction, and the other one of said seal rings ( 1 ) and ( 1 ) comprises another controller body ( 32 ) for controlling the displacement of said load ring ( 2 ) in a second periphery direction, said second periphery direction being opposite said first periphery direction.