Development of the Crown Motor

This paper describes a new fluid motor named "Crown Motor". It uses a new mechanism that consists of two crown gears with more than three cylinders around the rotation axis. The torque of this motor is high, with a high gear ratio of 77:1, accomplished by using only two crown gears, while rotation speed is slow enough (∼16 rpm) to allow for mobile robotic applications. The Crown Motor has been developed for the new fire fighter robot "Genbu" under construction in our laboratory. It has many advanced properties to be used in many applications: 1) it can drive with a low-pressure fluid (0.2∼0.7 MPa), like tap water (∼0.2 MPa); 2) it is able to control its torque and rotation speed independently when the supplied pressure of fluid is constant; and 3) it is easy to apply the motor to many kinds of machines such as used under (near) water or any kind of fluid. The electric and mechanical valve systems used are also described.