Experimental Validation of an Intelligent Hybrid Plain Bearing Active Control

Abstract

The replacement of damaged journal bearings in forming machines eventuates in very high personal and material costs as well as long-term downtime. Moreover, new discontinuous forming processes (e.g. press hardening, pendulum operations) have a negative effect on the hydrodynamic pressure built up in the bearing and can conduct to failure. Therefore, users and manufacturers of forming presses are looking for ways to improve the safety of this key component. In this paper, the concept of an intelligent hybrid plain bearing (IHPB) that combines hydrodynamic and hydrostatic characteristics, presented in [1], is detailed and validated on a test rig. The clearance state of the journal bearing is monitored through eddy current sensors and a controlled hydrostatic support is activated, when this state is evaluated as critical. The results show a strong increase in the load capacity and in the minimal lubrication gap of the IHPB within three series of tested experiments: stationary, nonstationary and press typical load cases.

Model-Based Design Approach to Improve Performance Characteristics of Hydrostatic Bearing Using Multivariable Optimization

“…The rotor bearing node's characteristics are improved by the integration of control techniques for thrust fluid bearings [11]. The eddy current sensors are used to monitor the gap of the hydrostatic bearing so that the load-carrying capacity can be improved by activating the hydrostatic support but there is deficiency in the low resolution of the eddy current sensors [12]. A servo control feedback system is introduced to monitor the fluid film gap and advance control techniques are proposed to improve the dynamic characteristics [13,14], but the deficiency is the lack of experimental validation.…”

Nonlinear Control of Hydrostatic Thrust Bearing Using Multivariable Optimization

“…Rehman [11][12][13][14] proposed a controlled servo valve to adjust recess pressure. Eberhardt [15] measured the clearance gap with the help of an eddy current sensor; hydrostatic support is activated when the clearance gap is critical. Rehman [16] proposed an active aerostatic thrust bearing, where high-speed pneumatic valves are used to control recess pressure and adjust fluid film thickness.…”