Patent ID: 7762722

Claim:
A linear motion guide unit comprising: an elongated guide rail having a first raceway groove extending lengthwise of the guide rail; and a slider allowed to move relatively to the guide rail by virtue of more than one rolling element comprising a plurality of rollers, the slider including: a carriage made thereon with a second raceway groove in opposition to the first raceway groove to form a load race between them and further made therein with a return passage extending in parallel with the load race, end caps secured to forward and aft ends of the carriage and each made therein with a turnaround passage to connect the load race and the return passage with one another, and the plurality of rollers being allowed to roll through a circulating circuit composed of the load race, return passage and a pair of the turnaround passages; wherein the return passage is defined by a hole inside a lengthwise tubular construction that fits into a bore made in the carriage, the tubular construction being made up of a tubular skeleton to guide the rollers therethrough and a porous compact to apply lubricant to the rollers, and the tubular skeleton being comprised of a column to guide any one of axially opposite ends of the roller, and a flexible spine to guide a circular rolling surface of the roller; and wherein the porous compact fits over the flexible spine in such a relation that a clearance remains between an outward surface of the flexible spine and an inward surface of the porous compact to permit flexing of the flexible spine to relieve a stress that is applied to the flexible spine by circulating motion of the rollers.