Abstract: A structure which ensures a movement of a seal lip disposed in a seal lip is realized by preventing foreign matters from permeating a seal internal space between a slinger and a seal ring. A labyrinth seal is disposed between an outer peripheral edge of a rotary side annular portion configuring the slinger and an inner peripheral surface of a stationary side cylindrical portion of a metal insert configuring the seal ring. In addition, a thickened portion is formed in a portion of an elastic member configuring the seal ring over an entire periphery. An auxiliary seal lip whose rigidity is lower than that of respective seal lips is disposed in the thickened portion over the entire periphery. The auxiliary seal lip prevents the foreign matters from adhering to the seal lip, and prevents the movement of the seal lip from being hindered.

Abstract: A roller bearing unit with a combination seal ring. Between the outer peripheral edge of a rotation side circular ring part constituting a slinger and the inner peripheral surface of the stationary side cylindrical part of a metal insert constituting the seal ring, there is formed a labyrinth seal. Also, in such part of an elastic member constituting the slinger as intervenes between the labyrinth seal and seal lip serving as a side lip, there is formed an auxiliary seal lip having lower rigidity than the seal lip. The whole axial length of the auxiliary seal lip in its free state is set in the range of 5.5˜7.5 times the thickness dimension thereof and the ratio of interference is set in the range of 0˜20% of the whole axial length of the free-state thereof.

Abstract: A structure which can ensure a movement of a seal lip 22a disposed in a seal lip 17a is realized by preventing foreign matters from permeating a seal internal space 26a between a slinger 16 and a seal ring 17a which configure a combination seal ring 12a. A labyrinth seal 27a is disposed between an outer peripheral edge of a rotary side annular portion 19 configuring the slinger 16 and an inner peripheral surface of a stationary side cylindrical portion 23 of a metal insert 20 configuring the seal ring 17a. In addition, a thickened portion 29 is formed in a portion of an elastic member 21 a configuring the seal ring 17a over an entire periphery. An auxiliary seal lip 32 whose rigidity is lower than that of respective seal lips 22a to 22c is disposed in the thickened portion 29 over the entire periphery. The auxiliary seal lip 32 prevents the foreign matters from adhering to the seal lip 22a, and prevents the movement of the seal lip 22a from being hindered.