Seal assembly and crawler-track connection structure

Abstract

A seal assembly has simple assembly structures, and provides secure sealing effects. A crawler-track connection structure allows the seal assembly to be easily mounted, and securely prevents overflow of a lubricant and the like to the outside. A pair of seal rings ( 1 ) and ( 1 ) individually having lip portions ( 23 ) and ( 23 ) are disposed such that each of the lip portions ( 23 ) and ( 23 ) protrudes in a direction opposing an axial direction, and a load seal ring ( 2 ) is compressed and inserted between the pair of seal rings ( 1 ) and ( 1 ). The load seal ring ( 2 ) exerts reaction forces on the pair of lip portions ( 23 ) and ( 23 ) outwardly in the axial direction.

1 - 3 . (canceled).  
   
   
       4 . A seal assembly comprising: 
 a pair of seal rings ( 1 ) and ( 1 ) individually comprising lip portions ( 23 ) and ( 23 ) disposed such that each of said lip portions ( 23 ) and ( 23 ) protrudes in a direction opposing an axial direction; and    a load seal ring ( 2 ) compressed and inserted between said seal rings ( 1 ) and ( 1 ), said load seal ring ( 2 ) exerting reaction forces on said lip portions ( 23 ) and ( 23 ) outwardly in the axial direction, wherein one of said seal rings ( 1 ) and ( 1 ) comprises said outer-diameter controller body ( 32 ) for controlling the displacement of said load seal ring ( 2 ) in the periphery outer direction, and the other one of said seal rings ( 1 ) and ( 1 ) comprises said inner-diameter controller body ( 32 ) for controlling the displacement of said load seal ring ( 2 ) in the periphery inner direction.    
   
   
       5 . The seal assembly as defined in one of claims  4 , wherein said load seal ring ( 2 ) comprises a circumferential groove ( 27 ) that tolerates axial-direction compression.  
   
   
       6 . The seal assembly as defined in one of  claims 4  to  5 , wherein a cross section of said seal assembly is symmetric with respect to a radial-direction line passing the center thereof,  
   
   
       7 . The crawler-track connection structure comprising: 
 a pin ( 8 ) to be inserted through superposed end portions of links ( 5 ) and ( 5 ); and    a seal assembly (S) externally fitted on said pin ( 8 ) for preventing overflow of a lubricant to the outside, the lubricant being supplied to an outer peripheral side of said pin ( 8 ), wherein    one of said links ( 5 ) and ( 5 ) is immobilized on said pin ( 8 );    the other one of said links ( 5 ) and ( 5 ) is supported on said pin ( 8 ) to be rotatable thereon; and    said seal assembly comprises 
 a load seal ring ( 2 ) disposed between radial-direction walls (W) and (W) opposing each other along an axial direction,  
 a first seal ring (I) comprising a lip portion ( 23 ) press-engaged with one of said radial-direction walls (W) and (W) according to a pressure exerted from said load seal ring ( 2 ), and  
 a second seal ring ( 1 ) comprising a lip portion ( 23 ) press-engaged with the other one of said radial-direction walls (W) and (W) according to a pressure exerted from said load seal ring ( 2 ).  
   
   
   
       8 . The crawler-track connection structure as defined in  claim 7 , further comprising a bushing ( 12 ) immobilized in the other one of said links ( 5 ) and ( 5 ) to be rotatable on said pin ( 8 ), and an end surface of said bushing functions as the one of said radial-direction walls (W) and (W).  
   
   
       9 . The crawler-track connection structure as defined in  claim 7 , further comprising: 
 a bushing ( 12 ) immobilized in the other one of said links ( 5 ) and ( 5 ) to be rotatable on said pin ( 8 ); and    a bushing ( 13 ) on the side of a sprocket ( 18 ),    wherein said seal assembly (S) is inserted between said bushing ( 12 ) and said bushing ( 13 ).    
   
   
       10 . The crawler-track connection structure as defined in one of  claims 7  to  9 , further comprising a ring body ( 31 ) disposed in an inner-diameter side of said load seal ring ( 2 ) for controlling the displacement of said load seal ring ( 2 ) in a periphery inner direction.  
   
   
       11 . The crawler-track connection structure as defined in one of  claims 7  to  9 , further comprising a dust seal ring ( 37 ) disposed in an outer peripheral side of said seal assembly (S).