Patent ID: 8397906

Claim:
An idler comprising: an idler tube ( 1 ), an idler shaft ( 7 ), a bearing seat ( 2 ) and a labyrinth seal structure at each end of the idler tube, in which the labyrinth seal structure comprises a seal ring ( 5 ) and a seal cover ( 3 ), wherein a flange ( 12 ) for positioning is provided on the top edge of the bearing seat, and the bearing seat is pressed into both ends of the idler tube ( 1 ) by means of interference fit after the bearing seat is coated with a sealant; a convex ring ( 4 ) and a clearer ( 9 ) are provided in the seal ring; a seal rim ( 3 - 1 ) of the seal cover is fitted between the convex ring and the clearer; and the thickness (b) of the convex ring is 0.1-3 mm, the height (f) of the convex ring is 2-50 mm, the gap (c)between the outer circumference of the convex ring and the seal rim ( 3 - 1 ) of the seal cover is 0.2-2 mm, and the distance (d) between the upside of the convex ring and the bottom of the seal cover is 2-50 mm, wherein the seal ring in the form of M shape is mounted onto the bearing seat by means of interference fit, and a storage compartment ( 10 ) is formed between the seal ring and a corresponding surface of the bearing seat; and wherein lubricating grease ( 11 ) is coated at the adjacent surfaces between the convex ring of the seal ring and the seal rim ( 3 - 1 ) of the seal cover, and the seal cover ( 3 ) is mounted onto the idler shaft ( 7 ) by means of interference fit.