LIQUID - LUBRICATED SPIRAL-GROOVE BEARINGS*)

Transcription

1 LIQUID - LUBRICATED SPIRAL-GROOVE BEARINGS*) BY J. BOOTSMA *) Thesis, Technological University Delft, 19 november Promotor: Prof. Dr Ir E. A. Muijderman. Philips Res. Repts Suppl. 1975, No. 7.

2 CONTENTS 1. GENERAL INTRODUCTION The operation of spiral-groove bearings A survey of the literature The aim of the present investigation 5 References 7 2. DIFFERENTIAL EQUATION FOR THE SMOOTHED PRES SURE Introduction The Reynolds equation Derivation of the differential equation for the smoothed pressure, in generalised coordinates The general differential equation for the smoothed pressure The differential equation for the smoothed pressure under stationary operating conditions Discussion The derivation of the smoothed-pressure equation Finite number of grooves Difference between grooves in the rotating member and grooves in the non-rotating member of the bearing Half-w whirl 25 References SPIRAL-GROOVE BEARINGS IN CONCENTRIC OPERATING CONDITIONS Introduction Axial load capacity, axial stiffness, and frictional losses of flat, conical, and spherical bearings Optimisation Optimisation with respect to load capacity P z and film thickness h r Optimisation with respect to axial stiffness of a bearing without a prescribed P z Optimisation with respect to axial stiffness of a bearing with a prescribed P z Load capacity P z, as h r -> 0, and take-off velocity co t Frictional losses Example of a calculation 36

3 Appendix ЗА 37 Appendix ЗВ 47 References THEORY OF SPIRAL-GROOVE JOURNAL BEARINGS Introduction Basic equations Differential equation Boundary conditions Rupture of lubricating film Load capacity Determination of pressure distribution and load capacity Perturbation method Numerical method Comparison of the results of the two approximation methods Stability Stability criterion for unloaded bearings The effect of the free boundary on the stability 67 Appendix 4A 73 Appendix 4B 81 Appendix 4C 85 References LOAD CAPACITY, FRICTIONAL LOSSES, AND STABILITY OF SPIRAL-GROOVE JOURNAL BEARINGS Introduction Completely herringbone-grooved journal bearing Comparison of load capacity of a completely herringbonegrooved journal bearing and a plain journal bearing Optimisation of groove parameters with respect to stiffness Load capacity, frictional losses, and stability as functions of groove and bearing parameters The effect of the width of the bushing on the load capacity of bearings with a free boundary Scheme of calculation Partially grooved journal bearings Spiral-groove journal bearings with a dead-end cavity Spiral-groove journal bearings with net axial flow of lubricant Viscous-screw pump 109 References 112

4 6. SPHERICAL AND CONICAL SPIRAL-GROOVE BEARINGS Introduction Theory Differential equation and boundary conditions Perturbation method ' Accuracy of the results Load capacity, stiffness, and frictional losses of spherical and conical bearings with a completely filled bearing gap Stability Comparison of bearing characteristics of spiral-groove spherical conical, and journal bearings Summary and possible further investigations 136 Appendix 6A 137 Appendix 6B 138 References EXPERIMENTS WITH SPIRAL-GROOVE JOURNAL BEAR INGS Introduction Test arrangements Spiral-groove journal bearings with free boundary Shape of interface independent of surface tension and forces of inertia The shape of the free boundary Load capacity and attitude angle Grooves in the housing or in the shaft Journal bearing with a free boundary Journal bearing with fixed boundary Stability Summary NO-LEAKAGE CONDITIONS OF SELF-SEALING HERRING BONE JOURNAL BEARINGS Introduction Leakage in conditions of concentric operating Experimental results Discussion of experimental results Leakage in conditions of eccentric operating Air ingestion Grease-lubricated herringbone journal bearings Some theoretical considerations 173

5 Breakdown of air-to-liquid interface in ungrooved section Leakage starting along plain bearing face Summary 180 References 181 List of symbols 183