Axial displacement and rotational speed monitoring
AssigneeROLLS-ROYCE plc
InventorsJonathan E. Holt, Stephen G. Garner, Mark J.E. Bellis
Life of this patent
Estimating the term…
Abstract
An apparatus, for example for a pitch change mechanism, includes a cylinder having a magnetic portion defining an annular array of features extending parallel to the longitudinal axis of the cylinder, the cylinder rotating in use and able to translate longitudinally. There is a sensing arrangement including a stationary magnetised core and two coils connected in series and wound around the core. In use, the cylinder rotates and current is induced in the coils. Monitoring equipment is arranged to calculate rotational speed of the cylinder from the frequency of the current and to calculate longitudinal position from the relative amplitude of the current in each coil. Also a method.
Claims12
Apparatus comprising
- a cylinder having a magnetic portion defining an annular array of features extending parallel to the longitudinal axis of the cylinder, the cylinder rotating in use and able to translate longitudinally;
- and
- a sensing arrangement comprising a stationary magnetised core arranged parallel to the features;
- and two coils connected in series via a common terminal and wound around the core, the common terminal of the coils and the other terminal of each coil connected to monitoring equipment;
- such that in use the cylinder rotates and current is induced in the coils by the cyclic variation of magnetic flux in the core;
- the monitoring equipment is arranged to calculate rotational speed of the cylinder from the frequency of the current and to calculate longitudinal position of the cylinder from the relative amplitude of the current in each coil.
A method of monitoring rotational speed and longitudinal position of a cylinder that rotates in use about its longitudinal axis and can translate longitudinally, the cylinder having a magnetic portion defining an annular array of features extending parallel to the longitudinal axis;
- the method comprising:
- providing a sensing arrangement comprising a stationary magnetised core arranged parallel to the features and two coils connected in series and wound around the core such that a variable magnetic flux is induced in the core and a current is induced in the coils by the passing of the features in use;
- calculating the rotational speed of the cylinder from the frequency of the current induced in the coils;
- and
- calculating the longitudinal position of the cylinder from the relative amplitude of the current in each coil.
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Dependencies are inferred from the claim text.