Sealing device

Abstract

A sealing apparatus capable of increasing a grease resistance property, wherein the tip of a sealing lip is formed so that an inner side contact angle α is equal to an open-air side contact angle β (α=β), that is, formed in a triangular shape to prevent grease inside the apparatus from leaking so as to increase the grease resistance property, and since the extending direction of the sealing lip is set at a middle of an inner side and an open-air side, a trouble such as the inversion of the sealing lip due to the occurrence of an inner pressure does not occur.

1 . A sealing apparatus for a universal joint, comprising: 
 an attachment portion attached to one member of two members that are arranged to be relatively movable;    a sealing lip extending from the attachment portion to the other member to be slidably in sealing contact with the other member; and    a dust lip extending to the other member to be slidably in contact with the other member while being tilted toward the open-air side from said attachment portion on the open-air side of the sealing lip,    wherein said sealing lip is provided to have an inner side contact angle which is an angle not smaller than an open-air side contact angle.    
   
   
       2 . A sealing apparatus according to  claim 1 , wherein said sealing lip has an extending direction that is tilted not less to the open-air side than the middle of the inner side and the open-air side.  
   
   
       3 . A sealing apparatus according to  claim 1 , wherein said dust lip is a double seal having two parts.  
   
   
       4 . A sealing apparatus according to  claim 1 , wherein said sealing lip has the inner side contact angle which is substantially equal to the open-air side contact angle, has the extending direction which is substantially the middle of the inner side and the open-air side, and has a sectional shape which is symmetric relative to the line of the extending direction.