Shaft monitoring system

Patent metadata

Field	Value
Publication number	US-2020200036-A1
Application number	US-201916690714-A
Country	US
Kind code	A1
Filing date	Nov 21, 2019
Priority date	Dec 20, 2018
Publication date	Jun 25, 2020
Grant date	—

Abstract

A monitoring system for monitoring the axial position of a rotating shaft includes a phonic wheel which is mounted coaxially to the shaft for rotation therewith. The phonic wheel includes a circumferential row of teeth. The system further includes a sensor configured to detect the passage of the row of teeth by generating an alternating measurement signal. The teeth are configured around the row such that the teeth contribute a component to the alternating measurement signal. The teeth are tapered in an axial direction of the wheel and the sensor is positioned relative to the phonic wheel such that, in use, axial displacement of the shaft causes the signal generated by the sensor to vary either or both of the amplitude and the pulse width of the component, whereby the axial position of the shaft can be monitored.

First claim

We claim:

1 . A monitoring system for monitoring the axial position of a rotating shaft, the system comprising:
a phonic wheel which is mounted coaxially to the shaft for rotation therewith, the phonic wheel comprising a circumferential row of teeth; and a sensor configured to detect the passage of the row of teeth by generating an alternating measurement signal; wherein the teeth are configured around the row such that the teeth contribute a component to the alternating measurement signal; and, wherein the teeth are tapered in an axial direction of the wheel such that the relative proportions of the teeth vary with axial distance across the phonic wheel, and the sensor is positioned relative to the phonic wheel such that, in use, axial displacement of the shaft causes the signal generated by the sensor to vary either or both of an amplitude and a pulse width of the component due to the variation in relative proportions, whereby the axial position of the shaft can be monitored.

2 . The monitoring system as claimed in claim 1 , wherein the teeth taper smoothly in the axial direction of the wheel.

3 . The monitoring system as claimed in claim 2 , wherein the teeth are tapered in height such that they are radially higher at one side of the phonic wheel than at an axially spaced other side of the phonic wheel.

4 . The monitoring system as claimed in claim 2 , wherein the teeth are tapered in width such that they are circumferentially wider at one side of the phonic wheel than at an axially spaced other side of the phonic wheel.

5 . The monitoring system as claimed in claim 2 , wherein the amount of taper varies linearly with axial distance across the phonic wheel.

6 . The monitoring system as claimed in claim 2 , wherein the amount of taper varies non-linearly with axial distance across the phonic wheel.

7 . The monitoring system as claimed in claim 1 , wherein the sensor is an electromagnetic or magnetic sensor that detects a varying distance caused by the passage of the row of teeth.

8 . The monitoring system as claimed in claim 7 , wherein the sensor detects absolute magnetic field strength between the sensor and the tooth, or wherein the sensor is a laser sensor that detects distance between the sensor and the teeth.

9 . The monitoring system as claimed in claim 1 , wherein in a normal operating mode of the shaft, the amplitude of the component is substantially equal.

10 . The monitoring system as claimed in claim 1 , wherein the circumferential row of teeth comprises one or more first teeth and one or more second teeth.

11 . The monitoring system as claimed in claim 10 , wherein in a normal operating mode of the shaft, either or both of the amplitude and the pulse width of the first teeth is substantially different to either or both of the amplitude and the pulse width of the second teeth.

12 . The monitoring system as claimed in claim 1 , wherein the circumferential row of teeth is interrupted by a special tooth from which the sensor generates a once-per-revolution signal, the special tooth being configured such that either or both of the amplitude and pulse width of the once-per-revolution signal is different from either or both of the amplitude and pulse width of the measurement signals of the further teeth over the entire axial range of the row.

13 . A gas turbine engine for an aircraft comprising:
an engine core comprising a turbine, a compressor, and a core shaft connecting the turbine to the compressor; and a monitoring system as claimed in claim 1 for monitoring the axial position of the core shaft, the phonic wheel being mounted coaxially to the core shaft for rotation therewith.

14 . The gas turbine engine as claimed in claim 13 , wherein:
the turbine is a first turbine, the compressor is a first compressor, and the core shaft is a first core shaft; the engine core further comprises a second turbine, a second compressor, and a second core shaft connecting the second turbine to the second compressor; and the second turbine, second compressor, and second core shaft are arranged to rotate at a higher rotational speed than the first core shaft.

15 . The gas turbine engine as claimed in claim 13 , further comprising:
an engine electronic controller which is operatively connected to the monitoring system to receive the overall signal and is configured to monitor therefrom the axial position of the shaft to which the phonic wheel is mounted.

16 . The gas turbine engine as claimed in claim 15 , wherein the engine electronic controller converts the signal into a shaft speed based on the frequency of the signal.

17 . A gas turbine engine for an aircraft comprising:
an engine core comprising a turbine, a compressor, and a core shaft connecting the turbine to the compressor; a fan located upstream of the engine core, the fan comprising a plurality of fan blades; and a gearbox that receives an input from the core shaft and outputs drive to the fan via an output shaft so as to drive the fan at a lower rotational speed than the core shaft; a thrust shaft that extends through the gearbox to connect the fan to an axial location bearing mounted on the core shaft, thereby relieving the output shaft of responsibility for axially locating the fan relative to the core shaft; and a monitoring system as claimed in claim 1 for monitoring the axial position of the thrust shaft, the phonic wheel being mounted coaxially to the thrust shaft for rotation therewith.

18 . The gas turbine engine as claimed in claim 17 , wherein:
the turbine is a first turbine, the compressor is a first compressor, and the core shaft is a first core shaft; the engine core further comprises a second turbine, a second compressor, and a second core shaft connecting the second turbine to the second compressor; and the second turbine, second compressor, and second core shaft are arranged to rotate at a higher rotational speed than the first core shaft.

19 . The gas turbine engine as claimed in claim 17 , further comprising:
an engine electronic controller which is operatively connected to the monitoring system to receive the overall signal and is configured to monitor therefrom the axial position of the shaft to which the phonic wheel is mounted.

20 . The gas turbine engine as claimed in claim 19 , wherein the engine electronic controller converts the signal into a shaft speed based on the frequency of the signal.

Assignees

• Rolls Royce Deutschland Ltd & Co Kg

Inventors

• Petersen Björn
• Hackenberg Peter

Classifications

• G01D2205/775

  Tapered profiles · CPC title

• Y02T50/60

  Efficient propulsion technologies, e.g. for aircraft · CPC title

• G01B21/00 Primary

  Measuring arrangements or details thereof, where the measuring technique is not covered by the other groups of this subclass, unspecified or not relevant · CPC title

• F16H1/20

  involving more than two intermeshing members · CPC title

• F01D21/003 Primary

  Arrangements for testing or measuring (for measuring vibrations G01H) · CPC title