Link rod manufacturing method

Abstract

In a method of manufacturing link rod which integrally joins bushes to each end of pipe-shaped arm portion, an extrusion molded bracket material ( 14 ) is formed to have the length allowing N pieces of the arm portions to be arranged in a horizontal row. Engaging projections ( 7 ) provided on the bracket material ( 14 ) are engaged with ends of the arm portions ( 2 ). Then, the ends of the arm portions ( 2 ) are butted against mounting walls ( 15 a ) provided on a mounting projection ( 15 ) of the bracket material 14 . N pieces of the arm portions ( 2 ) are arranged without clearance in a horizontal row with respect to the bracket material ( 14 ) to form butted portions in the shape of a continuous straight line. The friction stir welding is carried out along the butted portions. Then, the bracket material ( 14 ) is cut into the width of the bracket ( 4 ). The engaging projections ( 7 ) are formed by forming slits ( 18 ) at given intervals on a horizontal projection ( 17 ) extrusion molded integrally with the bracket material ( 14 ).

1 . A method of manufacturing a link rod which comprises an arm portion of longitudinal shape having a pair of spaced first and second walls parallel extending to each other and a third wall connecting between said first and second walls, and a bush mounting bracket being joined to an end in the longitudinal direction of said arm portion, wherein a bracket material is extrusion molded and cut in the longitudinal direction thereof to the length capable of forming a plurality of bush mounting brackets, a plurality of arm portions are arranged in a horizontal row with respect to said bracket material in the direction of extrusion of said bracket material, each end of said arm portions are butted against said bracket material such that such butted portions extend in the form of continuous straight line, each of said arm portions are friction stir welded to said bracket material along said butted portions in one process step, and then said bracket material is cut to the width of a bracket, comprises the steps of forming integrally on said bracket material a horizontal projection which projects in the direction crossing at a right angle the extrusion direction of said bracket material and extends continuously in the extrusion direction thereof, making vertical slits, each of which has the width allowing end of the third wall to be engaged, on said horizontal projection at predetermined intervals in the extrusion direction of said bracket material to form a plurality of separate engaging projections, having the ends of said third walls engaged with each of said slits and, at the same time, having said engaging projections fitted into spaces provided between said first wall and said second wall on the side of the ends of said arm portions, having each end of said first and second walls butted against said bracket material to be made flush with each other to form a continuous plane tool traveling surface across said arm portions arranged in a horizontal row. 
   
   
       2 . The link rod manufacturing method according to  claim 1 , wherein said arm portion is formed in the shape of a square pipe, a hollow portion opened to an end of the square pipe forms the space provided between said first and second walls, and said engaging projection is engaged with said hollow portion. 
   
   
       3 . The link manufacturing method according to  claim 1 , wherein said first and second walls are provided each with protrusions protruding from said third wall in a horizontal direction crossing at right angle the longitudinal direction of said arm portion, and the space into which said engaging projection is fitted is formed between said protrusions of said neighboring arm portions. 
   
   
       4 . A method of manufacturing a link rod which comprises a longitudinally extending arm portion having a pair of spaced first and second walls formed in parallel in a cross section crossing at a right angle the longitudinal direction thereof and a third wall connecting between said first and second walls, and a bush mounting bracket having a bush mounting hole and being integrally formed with an engaging projection to be engaged between said first and second walls on an longitudinal end of said arm portion, wherein said bush mounting bracket is friction stir welded to and formed integral with the longitudinal end of said arm portion, comprises the steps of forming a bracket material by extrusion molding such that an extrusion has in cross section a configuration of a front view of said bush mounting bracket when viewed from an axial direction of said bush mounting hole and is formed integral with a horizontal projection which projects in the direction crossing at a right angle the direction of extrusion and which extends continuously in the direction of extrusion and then by cutting the extrusion in the longitudinal direction thereof to such a predetermined length that a plurality of said bush mounting brackets are arranged in a horizontal row, forming an arm material by extrusion molding such that a cross section of an extrusion corresponds to a cross section, crossing at a right angle the longitudinal direction of each of said arm portions, in such a state that a plurality of said arm portions are arranged in a horizontal row, and such that the width of the extrusion corresponds to the cutting length of said bracket material and then by cutting the extrusion in the longitudinal direction thereof to a predetermined length of said arm portion, making vertical slits, each of which has the width allowing an end of said third wall to be engaged, on said horizontal projection at predetermined intervals in the extrusion direction of said bracket material to form a plurality of separate engaging projections, arranging said bracket material and said arm material in such a state that the extrusion directions of these materials cross at right angles each other so as to have the ends of said third walls fitted into the slits and at the same time to have said engaging projections fitted into spaces provided between said first wall and said second wall on the side of the ends of said arm portions, having each end of said first and second walls butted against said bracket material to be made flush with each other to form a continuous plane tool traveling surface across said arm portions arranged in a horizontal row and to form butted portions in the shape of continuous straight line, carrying out friction stir welding by letting a rotation tool travel on the tool traveling surface along said butted portions so as to integrate said bracket material with said arm material, and then cutting the joined bracket material and arm material into the width of a product.