Method for forming large-diameter gear through rack and toothed chain meshing type three-roller roll bending

The invention relates to the technical field of gear manufacturing, in particular to a toothed chain and a method for forming a large-diameter gear through rack and toothed chain meshing type three-roller roll bending. The method for forming the large-diameter gear through rack and toothed chain meshing type three-roller bending comprises the following steps that 1), the toothed chain and a rack are placed on a driven roller after the toothed chain and the rack are oppositely matched; 2), a driving roller is moved to a starting position of the rack, pressing the driving roller downwards and completing pre-bending are carried out; 3), the driving roller starts to roll at a last position of the previous step to finish rolling; 4), the driving roller is moved back to the original position tobe downwards contacted with the rack, and continuously pressing down is carried out; 5), the driving roller rotates to complete roll round; 6) the driving roller is moved to the tail end of the rack to complete roll bending o