Patent ID: 8033730

Claim:
A linear motion guide unit comprising: a guide rail having a first raceway surface extending lengthwise thereof, and a slider that fits over or conforms to the guide rail for movement relatively to the guide rail by virtue of more than one rolling element, the slider being composed of a carriage having a second raceway surface lying in opposition to the first raceway surface of the guide rail to define a load-carrying race between the first raceway surface and the second raceway surface and the slide further comprising a return passage extending in parallel with the second raceway surface, end caps secured on opposite ends of the carriage, and the end caps comprising turnaround passages to connect the load-carrying race with the return passage, and more than one rolling element allowed to roll through a circulating circuit made up of the load-carrying race, return passage and the turnaround passages; wherein the rolling element is a roller, the carriage has an overall length equivalent to substantially four times a width of the guide rail, and the second raceway surface on the carriage on the lengthwise end has crowning profiles each of which has a crowning length equivalent to 4±0.5 times as long as a diameter of the roller and also has a crowning depth equivalent to an amount of elastic deformation that occurs in the first raceway surface, the second raceway surface and the roller when the slider undergoes a load reaching a half of a static nominal standard load.