Torque-measurement device for a turbomachine shaft
The present invention relates to a torque-measurement device for a turbine engine shaft ( 1 ) including a proof body ( 7 ) capable of being mounted on the shaft, characterized in that the proof body ( 7 ) forms a mounting for at least one acoustic-wave strain gauge ( 20 ) and is magnetized such as to allow the torque to be measured by magnetostrictive effect. The invention also relates to a method for calibrating the torque-measurement system including a first step of calibrating said device, the device being mounted on a shaft but outside of the engine, by applying reference torques to the shaft with the device and by establishing a rule regarding the relationship between the strain measured by said strain gauge and the actual torque applied, a step of mounting the shaft with the device inside the turbine engine together with placement of the magnetostrictive measurement system, the calibration of the first step being optionally reset with the engine stopped, and a step of establishing a calibration rule regarding the relationship between the torque measured by magnetostrictive effect and the reference torque provided by the strain gauges.
1. Device for measuring the torque transmitted by a turbine engine shaft, comprising:
a test piece which can be mounted on the shaft, said test piece being capable of being magnetised and forming a support for at least one surface acoustic wave strain gauge,
means for measuring the torque by means of a magnetostrictive effect, using magnetostrictive measuring sensors which are capable of capturing a variation in the magnetic permeability of the magnetised test piece, and
means for calibrating the measurement of the torque by means of a magnetostrictive effect, which are capable of establishing a calibration law between the torque measured by said measuring means and a reference torque given by said at least one strain gauge.
2. Device according to claim 1 , the test piece of which has a tubular shape, said at least one strain gauge being fixed to the interior wall of the tubular test piece and comprises an antenna for transmitting signal which is connected to said at least one strain gauge, said tubular test piece being arranged so as to be mounted concentrically with said shaft and having two elements for fixing to the shaft, which elements are axially remote from one another.
3. Device according to claim 2 , of which at least one of the fixing elements is a friction fixing element.
4. Device according to claim 3 , of which at least one friction fixing element comprises a contact surface which is perpendicular to the axis of the tubular test piece.
5. Device according to claim 2 , of which at least one of the fixing elements comprises teeth which are arranged so as to cooperate with the teeth on the shaft which have a complementary shape.
6. Device according to claim 2 , the antenna of which is cylindrical.
7. Turbine engine shaft, comprising a measuring device according to claim 1 .
8. Shaft according to claim 7 , comprising a radial flange, one end of the device being held on the shaft by bearing axially against the flange.
9. Device according to claim 1 , wherein it comprises sensors which can be fixed on a stator part opposite the test piece for the magnetostrictive measurement, a fixed antenna which can receive the signals from said at least one strain gauge and a unit for processing the signal.
10. Method for calibrating a device for measuring the torque transmitted by a turbine engine shaft according to claim 1 , comprising:
a step of establishing a law between the strain measured by said at least one strain gauge and the actual torque applied outside the shaft,
a step of mounting the device on the shaft, and
a step of establishing a calibration law between the torque measured by means of a magnetostrictive effect and the reference torque given by said at least one strain gauge.
11. Shaft according to claim 8 wherein said radial flange comprises a jaw tooth connection at the other end thereof.