The optimum geometries of disk and cylindrical sprial groove viscous pumps to provide the maximum pressure or flow rate are investigated theoretically. The geometrical design parameters, such as the groove angle, groove to ridge clearance ratio, groove width ratio and ridge clearance ratio, are considered as functions of meridional coordinate. Results are obtained from the solution of a differential equation for the smoothed overall pressure distribution of a spiral groove viscous pump. It is found that outflow rate increases with the increase of groove to ridge clearance ratio λ, and that for each value of λ there exist “optimum” values of groove angle and groove width ratio, which give a maximum outflow rate. However, the increase of λ decreases the ridge clearance.

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The Linear DC Motor (LDM) are used for CD players and other many equipments, but these are MC-type LDMs as these movers are light. MM-type LDM has advantages at long stroke machines because its mover's feeding wires for driving is not necessary. But control system needs detectors for mover's position and velocity, so detectors are provided along whole stroke length. So that MM-type LDM is not so used because of its large structure for its driving element and detectors.The trial motor is MM-type LDM without wires, and its simple detector detects both position and velocity at every position along stroke length. As no-wire system, infrared rays transmits the detective signal to the controller. Using this signal, mover is cotrolled at constant velocity by Phase-Lock-Loop (PLL).On this system, an error by slip of detector is very small. This LDM drived without wires has good character as there is a little effect of this infrared rays transmitter at the velocity control.