Friction stir bonding method

Abstract

The end of a face plate 11 of a hollow member 10 is abutted against the end of a face plate of a hollow member 20 . The end of a face plate 21 is stacked to a protrusion 15 . A small-diameter portion 52 of a rotary tool 50 is inserted to the abutted area, and the tool 50 is moved along the abutted region while being rotated in the right direction observed from the large-diameter portion 51 . The direction of movement is from the front of the drawing of FIG. 1 toward the far end thereof. In FIG. 1 , the pressure of mobilized metal is greater in the right side of the axial center of the rotary tool. The thickness of the member from the tip of the inserted small-diameter portion 51 to the hollow areas 10 b and 10 a is thicker at the right side. Accordingly, the thickness of the member is greater at the right side of the tool where the pressure is higher, thus preventing metal from flowing out into the hollow region 10 a . Since the member positioned to the left side of the tool is thinner, the weight of the bonded member is reduced.

We claim:  
     
         1 . A friction stir bonding method for bonding a first member and a second member, the first member comprising a plate and a protrusion protruding substantially parallel to said plate from the end portion of said plate and arranged at a retreated position from one surface of said plate, said friction stir bonding method comprising the steps of: 
 superimposing the end portion of said second member on said protrusion, and abutting said end portion of said second member against the end portion of said plate; and    friction stir bonding the abutted portions using a rotary tool having a small-diameter portion mounted on the end of a large-diameter portion, by inserting said small-diameter portion to said abutted portions; wherein    the rotary tool is positioned so that when observed from the direction from which said tool moves along said abutted portions, the distance from the tip portion of said inserted small-diameter portion to the surface of said first member opposite from said large-diameter portion is greater in the right side of the axial center of said rotary tool than the left side thereof; and    said rotary tool is rotated in the right direction when observed from the large-diameter portion side while being moved along said abutted portions.    
     
     
         2 . A friction stir bonding method according to  claim 1 , wherein said protrusion is positioned to said right side when performing said friction stir bonding.  
     
     
         3 . A friction stir bonding method according to  claim 1  wherein the tip portion of said small-diameter portion is inserted to said protrusion when performing said friction stir bonding.  
     
     
         4 . A friction stir bonding method for bonding a hollow member comprising two substantially parallel face plates, a connecting plate for connecting said two face plates, a protrusion protruding substantially parallel to one face plate from said connecting plate, and a concave portion recessed both from the outer side of said one face plate and from the protruded direction of said protrusion at the joint portion joining said one face plate, said connecting plate and said protrusion; said friction stir bonding method comprising the steps of: 
 superimposing the end portion of a second member on said concave portion, and abutting said end portion of said second member against the end portion of said one face plate; and    friction stir bonding the abutted portions using a rotary tool having a small-diameter portion mounted on the end of a large-diameter portion, by inserting said small-diameter portion to said abutted portions and said protrusion; wherein    said protrusion is positioned to the right side of the axial center of said rotary tool when said rotary tool is observed from the direction from which said tool moves along said abutted portions;    the distance from the tip portion of said inserted small-diameter portion to the surface of said hollow member opposite from said large-diameter portion is greater in the right side of the axial center of said rotary tool having said protrusion than the left side thereof, when observed from the direction from which said tool moves; and    said rotary tool is rotated in the right direction when observed from the large-diameter portion side while being moved along said abutted portions.    
     
     
         5 . A friction stir bonding method for bonding a first member and a second member, the first member comprising a plate and a protrusion protruding substantially parallel to said plate from the end portion of said plate and arranged at a retreated position from one surface of said plate, said friction stir bonding method comprising the steps of: 
 superimposing the end portion of said second member on said protrusion, and abutting said end portion of said second member against the end portion of said plate; and    friction stir bonding the abutted portions using a rotary tool having a small-diameter portion mounted on the end of a large-diameter portion, by inserting said small-diameter portion to said abutted portions; wherein    the rotary tool is positioned so that when observed from the direction from which said tool moves along said abutted portions, the distance from the tip portion of said inserted small-diameter portion to the surface of said first member opposite from said large-diameter portion is greater in the left side of the axial center of said rotary tool than the right side thereof; and    said rotary tool is rotated in the left direction when observed from the large-diameter portion side while being moved along said abutted portions.    
     
     
         6 . A friction stir bonding method according to  claim 5  wherein said protrusion is positioned to said left side when performing said friction stir bonding.  
     
     
         7 . A friction stir bonding method according to  claim 5 , wherein the tip portion of said small-diameter portion is inserted to said protrusion when performing said friction stir bonding.  
     
     
         8 . A friction stir bonding method for bonding a hollow member comprising two substantially parallel face plates, a connecting plate for connecting said two face plates, a protrusion protruding substantially parallel to one face plate from said connecting plate, and a concave portion recessed both from the outer side of said one face plate and from the protruded direction of said protrusion at the joint portion joining said one face plate, said connecting plate and said protrusion; said friction stir bonding method comprising the steps of: 
 superimposing the end portion of a second member on said concave portion, and abutting said end portion of said second member against the end portion of said one face plate; and    friction stir bonding the abutted portions using a rotary tool having a small-diameter portion mounted on the end of a large-diameter portion, by inserting said small-diameter portion to said abutted portions and said protrusion; wherein    said protrusion is positioned to the left side of the axial center of said rotary tool when said rotary tool is observed from the direction from which said tool moves along said abutted portions;    the distance from the tip portion of said inserted small-diameter portion to the surface of said hollow member opposite from said large-diameter portion is greater in the left side of the axial center of said rotary tool having said protrusion than the right side thereof, when observed from the direction from which said tool moves; and    said rotary tool is rotated in the left direction when observed from the large-diameter portion side while being moved along said abutted portions.