Linear motion rolling guide unit

A linear motion rolling guide unit comprising:

• a track rail having first raceway grooves formed on longitudinally extending side wall surfaces thereof;
• a casing slidable relative to the track rail and having second raceway grooves formed at positions facing the first raceway grooves;
• end caps mounted to the longitudinal ends of the casing;
• rolling elements circulating through raceways formed between the first raceway grooves and the second raceway grooves;
• under seals having seal portions for sealing the casing, the end caps and the track rail, the under seals each including a core member and a seal member secured to the core member and having lip portions;
• insertion grooves formed on an inner lateral side of the end caps facing the track rail and on a far longitudinal side with respect to the casing, the insertion grooves extending in the lateral direction;
• and
• locking portions provided to the longitudinal ends of the core member and extending upwardly, the locking portions being adapted to fit laterally into the insertion grooves in the end caps to mount the under seal to the end caps.