Experimental Study of the Shaft Motion in the Journal Bearing of a Gear Pump

The movement of the shaft of a driven gear in a gear pump is experimentally studied. Three different methods are considered, and the use of a laser micrometer measurement method is validated. In order to use the laser micrometer, some modifications are made to the gear pump. Experimental results for different working pressures and rotational velocities are shown. For a low nondimensional working pressure, defined in a similar way as the Sommerfeld load, experimental and numerical results agree very well for relative eccentricity. Nevertheless, experimental results made clear that the role of the lateral plate of the pump is very important for high nondimensional working pressure. A value of 100 is given for the critical nondimensional working pressure in order to avoid wear and slant in the lateral plate. Frequency analysis of the outlet pressure, as well as the precise measurement of the wear in the pump case, support experimental observation of the inability of the journal to retain the shaft for high nondimensional pressure.