Bevel gear ordinary gear is the shape of a cylinder. The pitch angle of a gear is the angle between the face of the pitch surface and the axis. The most familiar kinds of bevel gears have pitch angles of less than 90 degrees and therefore are cone-shaped. This type of bevel gear is called external because the gear teeth point outward. The pitch surfaces of meshed external bevel gears are coaxial with the gear shafts; the apexes of the two surfaces are at the point of intersection of the shaft axes. Bevel gears that have pitch angles of greater than ninety
Type 90 Kyū-maru tank made Type 90 more challenging to operate outside Hokkaido. Some politicians therefore criticized the effectiveness of Type 90 due to difficulty in transportation. In fact, more than 65% of major bridges in Japan were still considered passable for Type 90 while overseas main battle tanks such as Challenger 2 and Leopard 2 could only use 40% of bridges in Japan. Type 90 Kyū-maru The is a main battle tank (MBT) of the Japan Ground Self-Defense Force (JGSDF). It was designed and built by Mitsubishi Heavy Industries as a replacement for all deployed Type 61 and Type 74 tanks, and