Mechanical seal

Abstract

To provide a mechanical seal in which degradation or tearing of a bellows does not occur, the spring constant of the bellows is reduced, and the fluctuation in the load due to stretching and contracting of the bellows is reduced. An inside-type mechanical seal includes a sleeve fixed to a rotating shaft, and a cartridge fixed to a housing. A rotation-side sealing ring is provided to the sleeve. A fixed-side sealing ring, which slides against the rotation-side sealing ring, and a bellows for axially urging the fixed-side sealing ring is provided to the cartridge. The bellows is made from a metal; and the metal bellows has one end fixed to a case for holding the fixed-side sealing ring and another end fixed to the cartridge. The plate thickness of the metal bellows is set so as to be smaller than the plate thickness of the case or the cartridge.

1 . An inside-type mechanical seal comprising a sleeve fixed to a rotating shaft, and a cartridge fixed to a housing; a rotation-side sealing ring being provided to said sleeve; and a fixed-side sealing ring, which slides against said rotation-side sealing ring, and a bellows for axially urging the fixed-side sealing ring, being provided to said cartridge; wherein:
 said bellows is made from a metal; and   said metal bellows has one end fixed to a case for holding said fixed-side sealing ring and another end fixed to said cartridge, the plate thickness of said metal bellows being set so as to be smaller than the plate thickness of said case or said cartridge.   
     
     
         2 . The mechanical seal according to  claim 1 , wherein: said metal bellows comprises a bellows part in which crest parts and trough parts are alternately formed, and a disc-shaped flange part extending radially outwards from said trough part at each end of the bellows part; and said bellows part is formed by molding or welding so that the outer diameter of said flange parts is greater than the diameter of said crest parts, and the inner diameter of said flange parts is substantially the same as or slightly larger than the diameter of said trough parts. 
     
     
         3 . The mechanical seal according to  claim 1 , wherein the fixing of said metal bellows to the metal case and the metal cartridge is performed by welding or fusing at each position located slightly further towards the inner diameter side relative to the outer diameter of said flange part of said metal bellows. 
     
     
         4 . The mechanical seal according to  claim 1 , wherein said rotation-side sealing ring is fixed to said sleeve via a cup gasket, and said cup gasket is provided across an outer circumferential surface and a side opposite the sealing face of said rotation-side sealing ring. 
     
     
         5 . An inside-type mechanical seal comprising a sleeve fixed to a rotating shaft, and a cartridge fixed to a housing; a rotation-side sealing ring being provided to said sleeve; and a fixed-side sealing ring, which slides against said rotation-side sealing ring, and a bellows for axially urging the fixed-side sealing ring, being provided to said cartridge; wherein:
 said bellows is made from a metal; and   said metal bellows has one end fixed to a gasket for holding said fixed-side sealing ring and another end fixed to said cartridge, the plate thickness of the metal bellows being set so as to be smaller than the plate thickness of said cartridge.   
     
     
         6 . The mechanical seal according to  claim 5 , wherein a band is attached on an outer circumference of an outer cylinder part of said metal bellows fitting into said gasket holding said fixed-side sealing ring. 
     
     
         7 . An inside-type mechanical seal comprising a sleeve fixed to a rotating shaft, and a cartridge fixed to a housing; a rotation-side sealing ring being provided to said sleeve; and a fixed-side sealing ring, which slides against said rotation-side sealing ring, and a bellows for axially urging the fixed-side sealing ring, being provided to said cartridge; wherein:
 said bellows is made from a metal; and   said metal bellows has one end directly fixed to said fixed-side sealing ring and another end fixed to said cartridge, the plate thickness of the metal bellows being set so as to be smaller than the plate thickness of said cartridge.   
     
     
         8 . The mechanical seal according to  claim 1 , being of a type in which a distal end of an inner cylinder part of said sleeve is expanded in diameter by crimping and caused to engage with an inner cylinder part of said cartridge, thereby preventing said cartridge and said sleeve from axial detachment, wherein:
 a portion of the inner cylinder part of said cartridge located on the opposite axial-direction side relative to said fixed-side sealing ring side is expanded in diameter and provided with a stepped part; and   
       said bellows is formed so that the inner diameter of a portion positioned on the fixed-side sealing ring side relative to the stepped part of the inner cylinder part of said cartridge is smaller than the inner diameter of a portion positioned on the opposite side from the fixed-side sealing ring relative to the stepped part of the inner cylinder part of said cartridge. 
     
     
         9 . The mechanical seal according to  claim 2 , wherein the fixing of said metal bellows to the metal case and the metal cartridge is performed by welding or fusing at each position located slightly further towards the inner diameter side relative to the outer diameter of said flange part of said metal bellows. 
     
     
         10 . The mechanical seal according to  claim 2 , wherein said rotation-side sealing ring is fixed to said sleeve via a cup gasket, and said cup gasket is provided across an outer circumferential surface and a side opposite the sealing face of said rotation-side sealing ring. 
     
     
         11 . The mechanical seal according to  claim 3 , wherein said rotation-side sealing ring is fixed to said sleeve via a cup gasket, and said cup gasket is provided across an outer circumferential surface and a side opposite the sealing face of said rotation-side sealing ring. 
     
     
         12 . The mechanical seal according to  claim 2 , being of a type in which a distal end of an inner cylinder part of said sleeve is expanded in diameter by crimping and caused to engage with an inner cylinder part of said cartridge, thereby preventing said cartridge and said sleeve from axial detachment, wherein:
 a portion of the inner cylinder part of said cartridge located on the opposite axial-direction side relative to said fixed-side sealing ring side is expanded in diameter and provided with a stepped part; and   said bellows is formed so that the inner diameter of a portion positioned on the fixed-side sealing ring side relative to the stepped part of the inner cylinder part of said cartridge is smaller than the inner diameter of a portion positioned on the opposite side from the fixed-side sealing ring relative to the stepped part of the inner cylinder part of said cartridge.   
     
     
         13 . The mechanical seal according to  claim 3 , being of a type in which a distal end of an inner cylinder part of said sleeve is expanded in diameter by crimping and caused to engage with an inner cylinder part of said cartridge, thereby preventing said cartridge and said sleeve from axial detachment, wherein:
 a portion of the inner cylinder part of said cartridge located on the opposite axial-direction side relative to said fixed-side sealing ring side is expanded in diameter and provided with a stepped part; and   
       said bellows is formed so that the inner diameter of a portion positioned on the fixed-side sealing ring side relative to the stepped part of the inner cylinder part of said cartridge is smaller than the inner diameter of a portion positioned on the opposite side from the fixed-side sealing ring relative to the stepped part of the inner cylinder part of said cartridge. 
     
     
         14 . The mechanical seal according to  claim 4 , being of a type in which a distal end of an inner cylinder part of said sleeve is expanded in diameter by crimping and caused to engage with an inner cylinder part of said cartridge, thereby preventing said cartridge and said sleeve from axial detachment, wherein:
 a portion of the inner cylinder part of said cartridge located on the opposite axial-direction side relative to said fixed-side sealing ring side is expanded in diameter and provided with a stepped part; and   said bellows is formed so that the inner diameter of a portion positioned on the fixed-side sealing ring side relative to the stepped part of the inner cylinder part of said cartridge is smaller than the inner diameter of a portion positioned on the opposite side from the fixed-side sealing ring relative to the stepped part of the inner cylinder part of said cartridge.   
     
     
         15 . The mechanical seal according to  claim 5 , being of a type in which a distal end of an inner cylinder part of said sleeve is expanded in diameter by crimping and caused to engage with an inner cylinder part of said cartridge, thereby preventing said cartridge and said sleeve from axial detachment, wherein:
 a portion of the inner cylinder part of said cartridge located on the opposite axial-direction side relative to said fixed-side sealing ring side is expanded in diameter and provided with a stepped part; and   said bellows is formed so that the inner diameter of a portion positioned on the fixed-side sealing ring side relative to the stepped part of the inner cylinder part of said cartridge is smaller than the inner diameter of a portion positioned on the opposite side from the fixed-side sealing ring relative to the stepped part of the inner cylinder part of said cartridge.   
     
     
         16 . The mechanical seal according to  claim 6 , being of a type in which a distal end of an inner cylinder part of said sleeve is expanded in diameter by crimping and caused to engage with an inner cylinder part of said cartridge, thereby preventing said cartridge and said sleeve from axial detachment, wherein:
 a portion of the inner cylinder part of said cartridge located on the opposite axial-direction side relative to said fixed-side sealing ring side is expanded in diameter and provided with a stepped part; and   said bellows is formed so that the inner diameter of a portion positioned on the fixed-side sealing ring side relative to the stepped part of the inner cylinder part of said cartridge is smaller than the inner diameter of a portion positioned on the opposite side from the fixed-side sealing ring relative to the stepped part of the inner cylinder part of said cartridge.   
     
     
         17 . The mechanical seal according to  claim 7 , being of a type in which a distal end of an inner cylinder part of said sleeve is expanded in diameter by crimping and caused to engage with an inner cylinder part of said cartridge, thereby preventing said cartridge and said sleeve from axial detachment, wherein:
 a portion of the inner cylinder part of said cartridge located on the opposite axial-direction side relative to said fixed-side sealing ring side is expanded in diameter and provided with a stepped part; and   said bellows is formed so that the inner diameter of a portion positioned on the fixed-side sealing ring side relative to the stepped part of the inner cylinder part of said cartridge is smaller than the inner diameter of a portion positioned on the opposite side from the fixed-side sealing ring relative to the stepped part of the inner cylinder part of said cartridge.   
     
     
         18 . The mechanical seal according to  claim 9 , being of a type in which a distal end of an inner cylinder part of said sleeve is expanded in diameter by crimping and caused to engage with an inner cylinder part of said cartridge, thereby preventing said cartridge and said sleeve from axial detachment, wherein:
 a portion of the inner cylinder part of said cartridge located on the opposite axial-direction side relative to said fixed-side sealing ring side is expanded in diameter and provided with a stepped part; and   said bellows is formed so that the inner diameter of a portion positioned on the fixed-side sealing ring side relative to the stepped part of the inner cylinder part of said cartridge is smaller than the inner diameter of a portion positioned on the opposite side from the fixed-side sealing ring relative to the stepped part of the inner cylinder part of said cartridge.   
     
     
         19 . The mechanical seal according to  claim 10 , being of a type in which a distal end of an inner cylinder part of said sleeve is expanded in diameter by crimping and caused to engage with an inner cylinder part of said cartridge, thereby preventing said cartridge and said sleeve from axial detachment, wherein:
 a portion of the inner cylinder part of said cartridge located on the opposite axial-direction side relative to said fixed-side sealing ring side is expanded in diameter and provided with a stepped part; and   said bellows is formed so that the inner diameter of a portion positioned on the fixed-side sealing ring side relative to the stepped part of the inner cylinder part of said cartridge is smaller than the inner diameter of a portion positioned on the opposite side from the fixed-side sealing ring relative to the stepped part of the inner cylinder part of said cartridge.   
     
     
         20 . The mechanical seal according to  claim 11 , being of a type in which a distal end of an inner cylinder part of said sleeve is expanded in diameter by crimping and caused to engage with an inner cylinder part of said cartridge, thereby preventing said cartridge and said sleeve from axial detachment, wherein:
 a portion of the inner cylinder part of said cartridge located on the opposite axial-direction side relative to said fixed-side sealing ring side is expanded in diameter and provided with a stepped part; and   said bellows is formed so that the inner diameter of a portion positioned on the fixed-side sealing ring side relative to the stepped part of the inner cylinder part of said cartridge is smaller than the inner diameter of a portion positioned on the opposite side from the fixed-side sealing ring relative to the stepped part of the inner cylinder part of said cartridge.