Double helical gear and method of welding double helical gear

The invention relates to a double helical gear and a method of welding the double helical gear. The double helical gear includes a rotating shaft, a first gear, a second gear, a first weld zone, and asecond weld zone. The first gear and the second gear are disposed side by side in an axial direction on the rotating shaft, the first gear includes a first teeth part, the second gear includes a second teeth part, and the first gear includes a first annular part to be fitted to the rotating shaft. The first weld zone is located on the first end surface, and has a welded part extending over a fitting portion between the first annular part and the rotating shaft as the first end surface is seen from the axial direction. The second weld zone is located on the second end surface of the first annular part at a gap between the first teeth part and the second teeth part in the axial direction. 本发明涉及人字齿轮和人字齿轮的焊接方法。人字齿轮具备旋转轴、第齿轮、第二齿轮、第焊接部和第二焊接部。第齿轮和第二齿轮在轴向上排列配置在旋转轴上，第齿轮在第齿轮的外周部包含第齿部，第二齿轮在第二齿轮的外周部包含第二齿部，第齿轮的第齿部与第二齿轮的第二齿部相对