Versatile water hydraulic motor driven by tap water

This paper proposes new types of a water hydraulic motor and a valve to control its speed which will be applied to the robots soaked in water. The big advantage of this motor is that it can be driven by such low pressure as tap water with high performance. The key of their mechanism is that the working fluid is completely wrapped by the soft tube and their machine moving parts contact the fluid indirectly. In other words, the deformation of the tube drives the motor, and reversely the valve makes the tube deformed to control the motor, which removes the risk of leakage without also requiring a seal. In addition, the valve to control the rotational speed is designed which can be driven by fluid power signal without using electricity. The motors can be used in places where electricity cannot be used safely, such as bathroom, sink, workshop over water, under water, etc. The basic driving principle and characteristics of the theoretical torque, the rotational speed, and the efficiency are described here with the results of the experiment.