Abstract: The turning bearing has a separator whose leading and trailing sides are concaved to fit over circular rolling surfaces of the rollers to provide concavities where concaved surfaces lying either in parallel with and in perpendicular to the axis of the roller. The rollers fit in the separator in either of two different directions. The separator can be easier installed into the raceway through a loading hole without the posture of the separator in mind. The separator has a quadrilateral in a transverse cross-section perpendicular to a traveling direction of the separator of which a peripheral surface is in opposition to the outer ring and the inner ring. The separator has a center through-hole. The concaved surfaces in the separator are contoured in arced or curved profiles and bulge gradually closer to a circular edge of the through-hole to form arcing bulges at bottoms of the curved surfaces.

Abstract: An effective contact length in race surfaces formed on grooved races cut in an outer ring and an inner ring is made as greater as permitted to improve the load-carrying capacity, and correspondingly guide parts born against axially opposite ends of a roller are made as less as possible in width to reduce frictional contact resistance applied to the axially opposite ends of the roller, thereby preventing a skew of the roller. An inside circular surface on the outer ring is staggered or different in level on opposite sides of a outside grooved race to make greater the race surface than an effective contact length of circular rolling surfaces of the rollers and correspondingly less the guide part in width than the race surface.

Abstract: A porous compact impregnated with lubricant fits into an end cap in a fashion exposed in part to a turnaround passage to apply the lubricant around balls while the balls roll through the turnaround passage, thereby realizing the maintenance-free condition for lubrication. The porous compact is placed in a concavity in an end cap major part and a slot rounded at opposite ends thereof is formed in an outside curved portion of the turnaround passage defined in the end cap major part to communicate the concavity with the turnaround passage. A leading edge of an applicator nose of the porous compact is exposed to the turnaround passage through an opening of the slot. The balls while being guided along edges of the slot come into rolling-contact with a contact area on the exposed surface of the porous compact to be applied or coated with the lubricant.

Abstract: A circular sleeve is disclosed which fits into a lengthwise bore in a slider to provide a return passage to make sure of smooth rolling in a slider downsized or compact in length. The sleeve is inserted with leaving circular clearances inside the lengthwise bore in the slider. The sleeve has a bridged beam portion and cantilevered beam portions all of which may undergo elastic deformation under urging or impact force caused by rollers while rolling through the return passage. The bridged beam portion is flanked by support beam portions forming the outside circular surface of the sleeve and the cantilevered beam portions are fastened at their inward ends to a middle support beam portion and freed at their outside ends to bend or warp.