抄録
Crowning on gear tooth surfaces has proved satisfactory in insuring good tooth bearings and preventing high stresses at the end of teeth due to inevitable errors in machining and assembling as well as slight deflections of shafts etc. caused by working loads. So the authors have investigated a simple method of crowning spur and helical gears on conventional gear hobbing machines. The method is as follows : As the hob head is fed vertically downwards in the course of hobbing, the work table, on which the gear blank is mounted, is drawn gradually outwards at first and then fed inwards. That is, the depth of cut is changed gradually along the width of teeth, where a regular depth of cut is maintained at the middle of the face of the teeth and slightly deeper at both ends, thus inflating the tooth surfaces. Spur gears and helical gears crowned by this method were tested minutely, and their good tooth bearings and ideal gearing motion are shown clearly. The authors have also investigated the suitable amount of crowning in order to have the desired width of tooth bearing.
