Flow forming connection of metallic parts and resultant part assembly

Abstract

A method and apparatus ( 10 ) provide a flow formed part assembly ( 12 ) having mechanically interlocked first and second metallic parts ( 22 ) and ( 24 ).

1 . A method for mechanically connecting metallic parts to each other, comprising:
 rotating first and second metallic parts with each other about a central axis with the first metallic part having an outer locking formation; and   rotating a flow forming tool about a tool axis at a location spaced radially outward from the central axis; and   moving the rotating flow forming tool axially along the central axis to flow form the second metallic part around the first metallic part in a mechanically interlocking relationship with the outer locking formation of the first metallic part.   
   
   
       2 . A metallic part flow forming connecting method as in  claim 1  wherein the outer locking formation of the first mechanical part includes circumferentially spaced locking projections about which the second metallic part is flow formed to provide both circumferential and axial mechanical interlocking of the parts to each other. 
   
   
       3 . A metallic part flow forming connecting method as in  claim 1  wherein the first and second metallic parts are selected from the group consisting of: parts made of different types of metals; parts having different heat treatments; parts having different compositions; parts made from blanks made by different processes; and combinations thereof. 
   
   
       4 . A metallic part flow forming connecting method as in  claim 1  wherein a plurality of flow forming tools are rotated about associated axes at a location spaced radially outward from the central axis, and the rotating flow forming tools being moved together axially along the central axis to provide the flow forming of the second metallic part around the first metallic part in its mechanically interlocking relationship with the outer locking formation of the first metallic part. 
   
   
       5 . A method for mechanically connecting metallic parts to each other, comprising:
 initially forming a first metallic part with an outer locking formation including locking projections spaced circumferentially and extending outwardly from a central axis;   rotating the first metallic part and a second metallic part with each other about the central axis;   rotating a flow forming tool about a tool axis at a location spaced radially outward from the central axis; and   moving the rotating flow forming tool axially along the central axis to flow form the second metallic part around the circumferentially spaced locking projections of the outer locking formation of the first metallic part in an axial and rotationally mechanically interlocking relationship.   
   
   
       6 . Apparatus for mechanically connecting metallic parts to each other, comprising:
 a spindle for rotatably mounting first and second metallic parts about a central axis with the first metallic part having an outer locking formation; and   a flow former including at least one rotary flow forming tool mounted for rotation about a tool axis at a location spaced radially outward from the central axis; and the flow forming tool being mounted for axial movement along the central axis during the rotation thereof to flow form the second metallic part around the first metallic part in a mechanically interlocking relationship with the outer locking formation of the first metallic part.   
   
   
       7 . Apparatus for mechanically connecting metallic parts as in  claim 6  wherein the spindle includes a mandrel and a tailstock between which the first and second metallic parts are axially clamped and supported for the rotation about the central axis. 
   
   
       8 . Apparatus for mechanically connecting metallic parts as in  claim 6  wherein the flow former includes a plurality of flow forming tools that are rotated about associated axes at a location spaced radially outward from the central axis and that are moved axially along the central axis to provide the flow forming of the second metallic part around the first metallic part. 
   
   
       9 . A metallic part assembly comprising:
 a first metallic part having a central axis and an outer locking formation including locking projections extending outwardly from and spaced about the central axis; and   a second metallic part that is flow formed around the outer locking formation of the first metallic part and located on opposite axial sides and circumferentially between the locking projections so as to mechanically interlock the first and second metallic parts to each other.   
   
   
       10 . A metallic part assembly as in  claim 9  wherein the first and second metallic parts are selected from the group consisting of: parts made of different types of metals; parts having different heat treatments; parts having different compositions; parts made from blanks made by different processes; and combinations thereof.