Patent ID: 8499905
Filing Date: 2013-08-06
Classification: B62K,F16F

Abstract:
1. A front fork comprising: a vehicle-body-side tube and a wheel-side tube slidably engaged with each other in fitting engagement; a damper cylinder disposed upright in the inside of vehicle-body-side tube; a piston rod disposed upright in an inside of wheel-side tube and inserted into the inside of the damper cylinder; a main piston mounted on the piston rod such that the main piston is brought into slidable contact with an inner peripheral surface of the damper cylinder and partitions the inside of the damper cylinder into a rod-side oil chamber and a piston-side oil chamber, and includes a damping force generating device; a sub piston slidably disposed in the inside of the damper cylinder above the main piston, said sub piston being brought into slidable contact with the inner peripheral surface of the damper cylinder for partitioning the inside of the damper cylinder into the piston-side oil chamber and a sub tank chamber, and includes a compression-side damping force generating device; a free piston disposed in the inside of the damper cylinder above the sub piston for pressurizing an oil chamber in the inside of the damper cylinder; a sealing cap mounted on an opening portion below the damper cylinder, for allowing the piston rod to penetrate therethrough, and includes a seal member which is brought into slidable contact with an outer periphery of the piston rod, for hermetically sealing the oil chambers in the inside of the damper cylinder from the oil chamber outside the damper cylinder; and a communication passage is formed in the piston rod for allowing the oil chambers in the inside of the damper cylinder and the oil chamber outside the damper cylinder to be in communication with each other when the front fork assumes a predetermined extension position from a ride-on stopping time to a fork maximum extended time, wherein the communication passage is an escape portion formed on an outer periphery of the piston rod facing the seal member in an opposed manner at the predetermined extension position of the front fork.