Conference article

The lubricant oil in experimentation of gear performance is highly influent on the tests results. This paper carries out a pump system control strategy to control the lubricant volume inside a gearbox of a test rig. Back-to-back test centers consist of one or more pairs of gearboxes connected back-to-back, what allows recirculation of mechanical power. These tests rigs are used to test fatigue life and efficiency of gears. The back-to-back rigs are made meeting standards requirements, which increase the reliability of results comparison between different sources. In fatigue life experiments, pitting and micro-pitting failures modes are highly sensitive to lubricant variations, due the oil capacity of decrease friction. The lubricant volume inside a gearbox also has high influence in efficiency, once high-volume levels relate to increased inertia and churning losses. Worldwide back-to-back tests rigs use constant oil volume in the gearboxes and controls the temperature inside the boxes. Once the back-to-back test rig presented in this paper has outside temperature control, due performance, two pumps are used to control the lubricant volume inside the gearboxes. This system has non linearities related to the motor pump torque response and the inside geometry of the gearboxes. With the objective of controlling the oil volume inside the gearbox, a Proportional Integrative Derivative (PID) controller was implemented to one hydraulic pump’s motor. It is defined ranges and limitations in the pump system operation to maintain the oil propagation in a linear relation to frequency regime. Using empiric experimentation, the PID parameters are defined. By controlling different oil volumes under the influence of different gear rotational speed, the controller has proved effectiveness by maintaining linear relation oil propagation and the volume variation inside the maximum permissible. The results leveraged the test rig to a high-precision level of torque efficiency and contact fatigue assessment in gears.

Control system, PID, gear lubricant, torque efficiency

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