Joint boot made of resin

Abstract

In a joint boot made of resin comprising a small-diameter cylinder part, a large-diameter cylinder part and a bellows part interlinking both and molded by injection blow molding, the small-diameter cylinder part constituting an injection molding section, the production of a burr at a boundary between the injection molding section and a blow molding section will be suppressed. To that end, the boundary at an outer periphery of the boot between the injection molding section and the blow molding section is set on a bellows part side away from a recess for fixation of the small-diameter cylinder part. In particular, a shoulder portion of the recess for fixation on the bellows part side is provided with a cutout portion, in which to set the boundary between the injection and the blow molding sections.

1 . A joint boot made of resin comprising a first cylinder part, a second cylinder part, and a bellows part integrally linking both and molded by injection blow molding, with said first cylinder part made into an injection molding section, 
 wherein said first cylinder part is provided at its outer periphery with a recess for fixation, and a boundary at an outer periphery of the boot between the injection molding section and a blow molding section is set on a bellows part side away from said recess for fixation.    
     
     
         2 . The joint boot made of resin as set forth in  claim 1 , wherein a shoulder portion of said recess for fixation on the bellows part side is provided with a cutout portion and said boundary between the injection molding section and the blow molding section is set in said cutout portion.  
     
     
         3 . The joint boot made of resin as set forth in  claim 2 , wherein said cutout portion includes a vertical area falling radially inwardly from an outer periphery of the first cylinder part and a slope area extending from an inboard end of the vertical area to a wall surface of said recess for fixation.  
     
     
         4 . The joint boot made of resin as set forth in  claim 3 , wherein the said slope area is of a curved surface.  
     
     
         5 . The joint boot made of resin as set forth in  claim 1 , wherein said first cylinder part is a small-diameter cylinder part and said second cylinder part is a large-diameter cylinder part coaxially disposed to the small-diameter cylinder part.  
     
     
         6 . A joint boot made of resin comprising a first cylinder part, a second cylinder part, and a bellows part integrally linking both, 
 wherein said first cylinder part is provided at its outer periphery with a recess for fixation and a shoulder portion of said recess for fixation on the bellows part side is provided with a cutout portion.    
     
     
         7 . The joint boot made of resin as set forth in  claim 6 , wherein said first cylinder part is a small-diameter cylinder part and the second cylinder part is a large-diameter cylinder part coaxially disposed to the small-diameter cylinder part.