Welding method, welding system, and welding jig for robotically welding a motorcycle fuel tank

Abstract

A welding jig for holding a motorcycle fuel tank when the fuel tank is welded includes a plurality of attachments for holding said fuel tank through resilient bodies. The plurality of attachments have springs hold the outer plate of a fuel tank, and an inner jig positions an inner plate. The attachments are attached to clamp arms which are opened/closed by cylinders. When the overlap portion between the outer and inner plates is welded, the thermal deformation caused by welding is accommodated by the springs. The attachments are spaced from the fuel tank in the order in which the welding point is approached.

1 . A welding jig for holding a motorcycle fuel tank when the fuel tank is welded, comprising:
 a plurality of attachments for holding said fuel tank through resilient bodies.   
   
   
       2 . A welding jig according to  claim 1 , wherein said attachments are mounted on respective arms, each of said arms having respective opening/closing mechanisms; and
 when said arms are fully opened, said arms are opened wide enough to allow said fuel tank to be attached and detached, and when said arms are fully closed, said arms are positioned by respective stoppers to hold said fuel tank with said attachments.   
   
   
       3 . A welding jig according to  claim 1 , wherein said attachments comprise pressing force adjusters for adjusting a pressing force with which said fuel tank is held. 
   
   
       4 . A welding jig according to  claim 1 , further comprising:
 an outer jig for supporting an outer side panel of said fuel tank; and   an inner jig for supporting an inner side panel of said fuel tank,   wherein said attachments are provided in said outer jig, and hold side portions and/or end portions of said outer side panel.   
   
   
       5 . A welding jig according to  claim 4 , wherein said outer side panel of said fuel tank comprises inwardly extended ends,
 wherein said attachments hold said fuel tank while outer surfaces of the ends of said outer side panel and inner surfaces of ends of said inner side panel are superposed, or while the ends of said outer side panel and the ends of said inner side panel are in abutment against each other.   
   
   
       6 . A welding jig according to  claim 1 , further comprising:
 a positioning mechanism for insertion into a fuel inlet defined in an upper surface of said fuel tank, and contacting an inner portion of said fuel tank to hold said fuel tank.   
   
   
       7 . A welding jig according to  claim 1 , wherein each of said attachments has a distal end abutting against said fuel tank, said distal end having a tilting mechanism tiltable in any direction.