Processing method of forming a concavity in a pipe member and an apparatus thereof

Abstract

Provided are a processing method of forming a concavity in a pipe member and an apparatus thereof, which allows to form a concavity in a pipe member with little shear droop produced in a corner portion of the concavity. According to the present invention, a plurality of rollers, each having similar shape and made of same material, is sequentially brought into contact with and pressed to the same site of processing on a pipe member to thereby deform that site. The quantity of deformation of the pipe is increased step by step, and finally the concavity of desired shape may be formed. The shear droop in a corner portion of thus formed concavity can be minimized since the quantity of deformation by each roller is controlled to be small and a plurality of processing operations is applied.

1 . A processing method of forming a concavity in a pipe member, comprising the steps of: 
 pressing a first roller moving linearly within a plane orthogonal to an axial line of a pipe member while rotating on its own axis, against an outer surface of the fixedly secured pipe member to thereby form a concavity in a site of contact on said pipe member; and    subsequently, pressing a second roller having the same shape as said first roller and also moving linearly within said orthogonal plane while rotating on its own axis, against the same site as said site of contact to thereby increase a dimension of said concavity so as to form the concavity of desired shape in said site of contact on said pipe member.    
   
   
       2 . A processing method of forming a concavity in a pipe member, comprising the steps of: 
 pressing a first roller having substantially cylindrical shape and moving within a plane orthogonal to an axial line of a pipe member while rotating on its own axis, against an outer surface of the fixedly secured pipe member to thereby form in a site of contact on said pipe member a concavity having a side wall defined by a planar surface orthogonal to the axial line of said pipe member; and    subsequently, pressing a second roller having the same shape as said first roller and moving within said orthogonal plane while rotating on its own axis, against the same site as said site of contact to thereby increase a dimension of said concavity so as to form the concavity having the side wall of desired height defined by the planar surface orthogonal to the axial line of said pipe member in said site of contact on said pipe member.    
   
   
       3 . A processing method of forming a concavity in a pipe member, in which a movable member is moved close to and away from a pipe member, which has been fixedly secured to a stationary member, within a plane orthogonal to an axial line of said pipe member such that a plurality of similarly configured rollers, each having substantially cylindrical shape and rotatably supported by said movable member, may be pressed against one and the same site of said pipe member in a sequential manner so as to form in the site of pressing on said pipe member a concavity having a side wall of desired height defined by a planar surface orthogonal to said axial line of said pipe member, wherein 
 among said plurality of rollers, as compared to a first roller that is firstly pressed against the specified site on the pipe member, a subsequent roller to be applied subsequently to the same site will be pressed toward a location of said pipe member closer to said axial line thereof than that for the first roller.    
   
   
       4 . A processing apparatus of forming a concavity in a pipe member, comprising: 
 a stationary member for fixedly securing a pipe member;    a first roller of substantially cylindrical shape, which is moved with respect to said fixedly secured pipe member within a plane orthogonal to an axial line thereof so as to be pressed against an outer surface of said pipe member while rotating on its own axis to thereby form in the site of contact on said pipe member a concavity having a side wall defined by a planar surface orthogonal to the axial line of said pipe member; and    a second roller configured into the same shape as said first roller, which is moved within said orthogonal plane so as to be pressed against the same site on said pipe member as said site of contact by said first roller while rotating on its own axis and to increase a dimension of said concavity to thereby form in said site of contact on said pipe member a concavity having a side wall of desired height defined by the planar surface orthogonal to the axial line of said pipe member.    
   
   
       5 . A processing apparatus of forming a concavity in a pipe member, comprising: 
 a stationary member for fixedly securing a pipe member;    a movable member which is moved close to and away from said pipe member fixedly secured to said stationary member within a plane orthogonal to an axial line of said pipe member; and    a plurality of similarly configured rollers, each having substantially cylindrical shape and supported rotatably by said movable member, which are pressed against one and the same location of said pipe member fixedly secured to said stationary member in a sequential manner as a result of said close-to and away-from motion of said movable member to thereby form in the site of pressing on said pipe member a concavity having a side wall of desired height defined by a planar surface orthogonal to the axial line of said pipe member.    
   
   
       6 . A processing apparatus of forming a concavity in a pipe member in accordance with  claim 5 , in which said plurality of rollers is installed in said movable member in such a manner that a distance between an axial line of each roller of said plurality of similarly configured rollers and the axial line of said pipe member measured in said site of pressing is set to be longest for a first roller to be firstly pressed against said site and the distance for the subsequent rollers to be pressed subsequently are reduced step by step in sequence.