ROTOR BALANCING METHOD

• US 20130340521A1
• Filed: 06/13/2013
• Published: 12/26/2013
• Est. Priority Date: 06/20/2012
• Status: Active Grant

• Current Assignee: Rolls-Royce PLC (Rolls-Royce Holdings Plc)
• Original Assignee: Rolls-Royce PLC (Rolls-Royce Holdings Plc)
• Inventors: CLARK, Daniel, TUPPEN, Stephen John
• Granted Patent: US 9,182,311 B2
• Time in Patent Office: Days
• US Class Current: 73/462
• CPC Class Codes: F01D 21/045 special arrangements in stators or in rotors dealing with breaking-off of part of rotor
• CPC Class Codes: F01D 25/04 Antivibration arrangements
• CPC Class Codes: F01D 25/06 for preventing blade vibration means on blade-carrying members or blades F01D5/00
• CPC Class Codes: F01D 5/027 Arrangements for balancing for balancing rotating bodies in general F16F15/32; for compensating unbalance G01M1/36
• CPC Class Codes: F01D 5/10 Anti- vibration means specially adapted for radial flow machines or engines F01D5/04
• CPC Class Codes: F01D 5/16 for counteracting blade vibration
• CPC Class Codes: F01D 5/26 Antivibration means not restricted to blade form or construction or to blade-to-blade connections or to the use of particular materials
• CPC Class Codes: F04D 29/321 for axial flow compressors
• CPC Class Codes: F04D 29/662 Balancing of rotors compensating unbalance G01M1/36
• CPC Class Codes: G01M 1/16 by oscillating or rotating the body to be tested
• CPC Class Codes: G01M 1/32 by adding material to the body to be tested, e.g. by correcting-weights
• CPC Class Codes: Y02T 50/60 Efficient propulsion technologies, e.g. for aircraft

Abstract

A method of balancing a physical rotor includes: determining a first balance state of the physical rotor at one or more rotational frequencies; identifying one or more balance zones on a surface of the rotor; providing a computerised simulation of the rotor having the first balance state; providing a first test mass in a first test location within one of the balance zones on the rotor simulation; determining a second balance state of the rotor simulation; providing at least one subsequent test mass in at least one subsequent test location within a balance zone on the rotor simulation and determining at least one subsequent balance state of the rotor simulation; selecting a mass and location from one of the first and subsequent test masses and test locations; and performing a material deposition process to add the selected mass of material to the selected location on the physical rotor.

Claims

1. A method of balancing a physical rotor, the method comprising the steps of:

determining a first balance state of the physical rotor;

identifying one or more balance zones on a surface of the rotor;

providing a computerised simulation of the rotor having the first balance state;

providing a first test mass in a first test location within one of the balance zones on the rotor simulation;

determining a second balance state of the rotor simulation;

providing at least one subsequent test mass in at least one subsequent test location within a balance zone on the rotor simulation and determining at least one subsequent balance state of the rotor simulation;

selecting a mass and location from one of the first and subsequent test masses and test locations which provides a predetermined balance state; and

performing a material deposition process to add the selected mass of material to the selected location on the physical rotor.

2. A method according to claim 1, wherein the selected mass and location comprises the test mass and test location having a minimal balance mass which provides the predetermined balance state.

3. A method according to claim 1, wherein the selected mass and location comprises the test mass and test location having a minimal rotor tensile load for a predetermined balance state at a maximum in use rotational frequency.

4. A method according to claim 1, wherein the selected mass and location comprises the test mass and test location having a minimal balance mass which provides the predetermined balance state and having a rotor tensile load for a predetermined balance state at a maximum rotational frequency below a predetermined amount.

5. A method according to claim 1, wherein the selected mass and location comprises the test mass and test location having a minimal rotor tensile load for a predetermined balance state at a maximum rotational frequency and having a balance mass below a predetermined amount.

6. A method according to claim 1, wherein the one or more balance zones are identified on the basis of areas of the rotor having one or more of a maximum predicted stress in use, a maximum likelihood of crack propagation following material deposition, minimum accessibility requirements, minimum load tolerance, minimum damage tolerance and maximum expected cycle fatigue.

7. A method according to claim 4, wherein where the rotor comprises titanium alloy, the maximum predicted stress in use of the balance zone is less than 200×

10⁶ Pascals (Pa).

8. A method according to claim 4, wherein where the rotor comprises nickel based alloy, the maximum predicted stress in use of the balance zone is less than 600×

10⁶ Pascals (Pa).

9. A method according to claim 1, wherein the material deposition process comprises one of blown powder direct laser deposition, plasma welding, Tungsten Inert Gas (TIG) welding, Metal Inert Gas (MIG) welding, PVD or CVD.

10. A method according to claim 1, wherein the method is repeated at a first rotational frequency and at a second rotational frequency.

11. A method according to claim 1, wherein the material deposited to the selected balance location has a density gradient.