Linear guideway and track module thereof

A linear guideway, comprising:

• an elongated spacer defining a longitudinal direction, wherein the spacer has a receiving portion and two engaging portions, the receiving portion has a plurality of thru-holes arranged in a row along the longitudinal direction and spaced apart from each other, the engaging portions are respectively arranged on two opposite edges of the receiving portion;
• a plurality of rollers respectively arranged in the thru-holes of the spacer;
• and
• two elongated sliding blocks, wherein each sliding block has a rolling groove and an engaging groove concavely formed on a bottom portion of the rolling groove, each rolling groove has two track surfaces spaced apart from each other, and each engaging groove is in air communication with the corresponding rolling groove,
• wherein the engaging portions of the spacer are respectively and slidably inserted into the engaging grooves of the sliding blocks along the longitudinal direction, thereby sustaining sliding of each sliding block only along the longitudinal direction with respect to another sliding block,
• wherein the track surfaces of each sliding block are respectively arranged at two opposite sides of the receiving portion of the spacer, each roller is respectively arranged in the rolling grooves of the sliding blocks, and the rollers are rollably clamped between the track surfaces of the sliding blocks by respectively inserting the engaging portions into the engaging grooves.