Patent ID: 7237954

Claim:
A rolling element retainer for a linear guideway, comprising a plurality of loaded-area retainers and a plurality of direction-changing-area retainers, and an end of a rolling groove of the respective the direction-changing-area retainer is located at an inner side of a projection part of two end caps of the rolling element retainer; wherein the loaded-area retainer is provided at both ends thereof with an outward extension for mating with the direction-changing-area retainer, and the extension extends in a direction of a rolling groove of the loaded-area retainer and abuts against the projection part of the end caps of the rolling element retainer, the extension is located outside of a guiding portion of the direction-changing-area retainer, a length of the extension is optimally expressed as: A+M>B>A=L×w×Δt+ 2 p wherein A represents a gap left between the direction-changing-area retainer and the loaded-area retainer, B is a length of the extension, L represents a length of the loaded-area retainer, M represents a distance from a top and a bottom of the direction-changing-area retainer, p represents manufacturing tolerance range, Δt represents a range of operating temperature, and w represents a coefficient of thermal expansion.