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Bearing selection and spindle design
NEWS
Bearing selection and spindle design To improve machine tool spindle design and bearing selection Timken have introduced 'Bearing systems analyses' techniques. The techniques, which are based on a test procedure called Computer Oriented Bearing Response Analysis (COBRA) enable static and dynamic analyses, bearing spring rate, heat generation and thermal balance to be determined. By use of COBRA, a bearing's dynamic resistance to relative radial and tilting motion of the inner race to the outer race, under harmonic exciting forces up to about 1000 cycle/s (equivalent to 60 000 rev/min spindle speed), can be measured. The COBRA program output normally includes all critical frequencies found within a specified speed range, mode shape plots of rotor and support housing at these frequencies, plots and tabulations of shear forces and bending moments in rotor and support housing - for any desired speed and loading condition; tabulations and plots of slope and deflections for these conditions; kinetic and potential energies in each structural component; and complete tabulation of bearing forces, showing magnitude and phase angle for each frequency in a specified speed range. Because COBRA is in the development stage, its use at this time is on a co-operative basis and limited to customers capable of providing experimental data on an actual machine. When it is completely developed, COBRA will be able to perform a complete static and dynamic analysis of customers' designs.
steam turbine generators, wet gas centrifugal compressors, hydraulic oil sumps, and heat-treatment quench tanks. Notable users include the BP Isle of Grain Refinery, who have fitted separators to British Thomson Houston steam turbines, and the US Navy who approve installation on seagoing generating sets upto 1000 kW. The GF2 Separator (Fig 1) operates on the Hero turbine principle, an inner rotor being driven at high speed by twin jets of partly contaminated fluid to separate the heavier and lighter phases. The heavier phase, water, moves to the rotor wall where two small diameter pipes collect it for discharge through a valve at the top of the unit. The valve can be controlled automatically or manually. The lighter phase, oil, remains near the centre of the rotor and is returned through a vertical tube to the oil system. For satisfactory operation, the separator requires a contaminated fluid flow of about 9 1/min (2 gal/min) at a pressure between 7 bar (100 lbf/in 2) and 2 bar (30 lbf/in2). Given a fluid supply of this order, rotor speed will be up to 5000 rev/min, and the contaminating fluid removal rate upto 0.084 1/min (0.0185 gal/min). The GF2 Separator has no replaceable elements and requires no maintanance, but can be dismantled, should cleaning be required after long periods of operation. The Glacier Metal Co Ltd, Alperton, Wembley, Middlesex HA0 1HD, England
The Timken Company, 1835 Dueber Avenue SW, Canton, Ohio 44706, USA
Lubrication of contractors plant Duckhams Oils have produced a film entitled 'The Movers', which deals with the lubrication of modern public works plant and transport and the demands made on the lubricant by modern vehicle design, working conditions and motorway operation. Designed primarily for showing to plant and vehicle operators (at foreman level) the film explains the technology and development, selection, storage and distribution of lubricants for contractors plant. The film is a 16 mm colour production with optical sound track and runs for 191A minutes. Industrial Division, Duckhams Oils, Summit House, West Wickham, Kent, England
Separator for removing water from lubricating oil Water leakage into lubricating oil systems constitutes a major hazard in plant such as steam turbine generator sets. Although leakage often cannot be prevented, systems can be protected by equipment which will remove contaminants from the oil. The Glacier Metal Company has developed a centrifugal separator for this purpose. Known as the GF2 Separator, it has been applied to
TRIBOLOGY December 1972
243
Bearing selection and spindle design To improve machine tool spindle design and bearing selection Timken have introduced 'Bearing systems analyses' techniques. The techniques, which are based on a test procedure called Computer Oriented Bearing Response Analysis (COBRA) enable static and dynamic analyses, bearing spring rate, heat generation and thermal balance to be determined. By use of COBRA, a bearing's dynamic resistance to relative radial and tilting motion of the inner race to the outer race, under harmonic exciting forces up to about 1000 cycle/s (equivalent to 60 000 rev/min spindle speed), can be measured. The COBRA program output normally includes all critical frequencies found within a specified speed range, mode shape plots of rotor and support housing at these frequencies, plots and tabulations of shear forces and bending moments in rotor and support housing - for any desired speed and loading condition; tabulations and plots of slope and deflections for these conditions; kinetic and potential energies in each structural component; and complete tabulation of bearing forces, showing magnitude and phase angle for each frequency in a specified speed range. Because COBRA is in the development stage, its use at this time is on a co-operative basis and limited to customers capable of providing experimental data on an actual machine. When it is completely developed, COBRA will be able to perform a complete static and dynamic analysis of customers' designs.
steam turbine generators, wet gas centrifugal compressors, hydraulic oil sumps, and heat-treatment quench tanks. Notable users include the BP Isle of Grain Refinery, who have fitted separators to British Thomson Houston steam turbines, and the US Navy who approve installation on seagoing generating sets upto 1000 kW. The GF2 Separator (Fig 1) operates on the Hero turbine principle, an inner rotor being driven at high speed by twin jets of partly contaminated fluid to separate the heavier and lighter phases. The heavier phase, water, moves to the rotor wall where two small diameter pipes collect it for discharge through a valve at the top of the unit. The valve can be controlled automatically or manually. The lighter phase, oil, remains near the centre of the rotor and is returned through a vertical tube to the oil system. For satisfactory operation, the separator requires a contaminated fluid flow of about 9 1/min (2 gal/min) at a pressure between 7 bar (100 lbf/in 2) and 2 bar (30 lbf/in2). Given a fluid supply of this order, rotor speed will be up to 5000 rev/min, and the contaminating fluid removal rate upto 0.084 1/min (0.0185 gal/min). The GF2 Separator has no replaceable elements and requires no maintanance, but can be dismantled, should cleaning be required after long periods of operation. The Glacier Metal Co Ltd, Alperton, Wembley, Middlesex HA0 1HD, England
The Timken Company, 1835 Dueber Avenue SW, Canton, Ohio 44706, USA
Lubrication of contractors plant Duckhams Oils have produced a film entitled 'The Movers', which deals with the lubrication of modern public works plant and transport and the demands made on the lubricant by modern vehicle design, working conditions and motorway operation. Designed primarily for showing to plant and vehicle operators (at foreman level) the film explains the technology and development, selection, storage and distribution of lubricants for contractors plant. The film is a 16 mm colour production with optical sound track and runs for 191A minutes. Industrial Division, Duckhams Oils, Summit House, West Wickham, Kent, England
Separator for removing water from lubricating oil Water leakage into lubricating oil systems constitutes a major hazard in plant such as steam turbine generator sets. Although leakage often cannot be prevented, systems can be protected by equipment which will remove contaminants from the oil. The Glacier Metal Company has developed a centrifugal separator for this purpose. Known as the GF2 Separator, it has been applied to
TRIBOLOGY December 1972
243