The assembly is the baseline mechanical system.
The spindle contains the shaft as the moving element, radial aerostatic bearings, a double-acting aerostatic thrust bearing, a radial gas-turbine drive and the grinding tool as the working organ.
It is classified as non-contact because rotor support and torque generation are achieved without mechanical contact: through pressurised gas films in the bearings and gas flow in the turbine drive.
Four functional elements define the system model.
- Moving element: shaft, rotor mass distribution and tool interface.
- Non-contact supports: radial and thrust bearing states, their coefficients and locations.
- Drive unit: torque source, configuration and position in the assembly.
- Working organ: grinding tool, process loads and required accuracy.
The assembly drawing defines their physical arrangement. The structural model defines their functional and parametric relationships.
A local bearing improvement is not automatically a spindle improvement.
An increase in local stiffness or load capacity can change the complete rotor–support system. The consequences may appear in shaft displacement, support reactions, natural frequencies, critical-speed separation and unbalance response.
- Support layout changes the effective boundary conditions of the shaft.
- Bearing coefficients depend on the selected operating state and coordinate basis.
- Shaft geometry and mass distribution determine how the support state enters the modes.
- The drive and working organ define additional loads, moments and interface constraints.
The rational sequence begins with architecture.
This system-first principle later became part of the AURA workflow. The bearing remains a calculation object. The spindle remains the engineering system that must satisfy the process requirements.
How AURA uses the structural prototype.
AURA connects the selected bearing geometry and operating state to the drive–shaft–tool configuration. The resulting support state can then be carried into critical-speed, mode-shape and response analysis before detailed CAD and CFD are committed.