Abstract: A linear motion guide unit includes a rail having first rolling surfaces extending longitudinally parallel to each other, a movable slider fitting over the rail, second rolling surfaces opposing the first rolling surfaces, respectively, rolling elements that roll while contacting the first and second rolling surfaces, a loop path through which the rolling elements circulate composed of a load-carrying race formed with the first and second rolling surfaces, a first circulation passage formed in the slider parallel to the load-carrying race, and two second circulation passages connecting the load-carrying race and the first circulation passage. The load-carrying race has a first portion at a boundary with the second circulation passage, and a contact angle of the rolling element with the second rolling surface in the first portion is greater than a contact angle of the rolling element with the second rolling surface in a remaining portion of the load-carrying race.

Abstract: A linear motion guide unit 1 includes a rail 10 having a pair of first rolling surfaces extending parallel to each other in a longitudinal direction, a slider 100 that fits over the rail in a relatively movable manner and has a pair of second rolling surfaces opposing the pair of first rolling surfaces, respectively, and a plurality of spheres as rolling elements 200 that roll while contacting the first and second rolling surfaces. The unit 1 has a loop path composed of a load-carrying race 102 formed with the first and second rolling surfaces, a first circulation passage 103 parallel to the load-carrying race and formed in the slider, and two second circulation passages 104 connecting the load-carrying race 102 and the first circulation passage 103, and the rolling elements 200 circulate through the loop path.