Methods and Systems for Ultrasonic Inspection of Rotating Shafts

• US 20100031751A1
• Filed: 08/08/2008
• Published: 02/11/2010
• Est. Priority Date: 08/08/2008
• Status: Active Grant

• Current Assignee: Toyota Motor Engineering & Manufacturing North America Incorporated (Toyota Motor Corporation)
• Original Assignee: Toyota Motor Engineering & Manufacturing North America Incorporated (Toyota Motor Corporation)
• Inventors: Smith, Gordon E., Perkins, Blair C.
• Granted Patent: US 8,028,581 B2
• Time in Patent Office: Days
• US Class Current: 73/622
• CPC Class Codes: G01N 2291/101 one transducer
• CPC Class Codes: G01N 2291/2634 cylindrical from outside
• CPC Class Codes: G01N 29/11 by measuring attenuation of acoustic waves
• CPC Class Codes: G01N 29/27 by moving the material relative to a stationary sensor
• CPC Class Codes: G01N 29/346 with amplitude characteristics, e.g. modulated signal

Abstract

A method of inspecting a rotatable shaft for the presence of defects may include continuously rotating a shaft under an applied load. As the shaft is rotated, an ultrasonic signal may be propagated along the length of the shaft. Attenuated or reflected ultrasonic signals may be collected from the shaft as the shaft is rotated. The presence of a defect in the shaft is determined by analyzing the collected ultrasonic signals.

Claims

1. A method of inspecting a rotatable shaft for the presence of defects, the method comprising:

propagating an ultrasonic signal along a length of the shaft as the shaft is continuously rotated about an axis of rotation under an applied load;

collecting ultrasonic signals from the shaft as the shaft is rotating; and

determining if a defect is present in the shaft based on the collected ultrasonic signals.

2. The method of claim 1 wherein the collected ultrasonic signal is indicative of a defect in the shaft if an amplitude of the collected ultrasonic signal increases and decreases in synchronization with the rotation of the shaft.

3. The method of claim 1 wherein determining if a defect is present in the shaft comprises comparing the collected ultrasonic signals to a baseline signature for a shaft without defects.

4. The method of claim 1 further comprising determining a position of the defect in the shaft when the collected ultrasonic signals are indicative of a defect in the shaft.

5. The method of claim 4 wherein the position of the defect in the shaft is determined based on collected ultrasonic signals corresponding to measurable features on the shaft.

6. The method of claim 1 wherein the ultrasonic signal is propagated along the length of the shaft by an ultrasonic transducer attached to an end of the shaft and the ultrasonic transducer is operatively connected to a control unit operable to control a frequency and intensity of the ultrasonic signal propagated along the shaft.

7. The method of claim 6 wherein the collected ultrasonic signals are reflected ultrasonic signals and the ultrasonic transducer is operable to collect reflected ultrasonic signals, convert the reflected ultrasonic signals to electronic signals indicative of the reflected ultrasonic signals, and pass the electronic signals to the control unit;

and

the control unit is operable to receive electronic signals from the ultrasonic transducer, store the electronic signals from the ultrasonic transducer in a memory and display the electronic signals on a display.

8. The method of claim 6 wherein the collected ultrasonic signals are attenuated ultrasonic signals and the attenuated ultrasonic signals are collected and converted to electronic signals by a receiver attached to an end of the shaft opposite the ultrasonic transducer and wherein the receiver is operatively connected to the control unit;

and

the control unit is operable to receive electronic signals from the receiver, store the electronic signals from the ultrasonic transducer in a memory and display the electronic signals on a display.

9. The method of claim 1 wherein the shaft comprises a take-up shaft for an automobile conveyor system.

10. The method of claim 1 wherein the ultrasonic signal propagated along the length of the shaft has a frequency from about 0.1 MHz to about 50 MHz.

11. The method of claim 1 wherein the shaft is inspected in situ.

12. A method for inspecting a solid rotating shaft for defects, the method comprising:

propagating an ultrasonic signal along a length of the shaft as the shaft is continuously rotated under an applied load such that, if a defect is present in the shaft, the defect opens and closes as the shaft is rotated;

collecting reflected ultrasonic signals from the shaft; and

determining if a defect is present in the shaft based on a change in amplitude of the reflected ultrasonic signals as the shaft is rotated under the applied load.

13. The method of claim 12 wherein when a defect is present, the amplitude of the reflected ultrasonic signal corresponding to the defect increases and decreases in synchronization with the rotation of the shaft.

14. The method of claim 12 wherein determining if a defect is present comprises comparing the reflected ultrasonic signals to a baseline signature for an undamaged shaft.

15. The method of claim 12 further comprising determining a position of the defect in the shaft based on the reflected ultrasonic signals.

16. The method of claim 15 wherein the position of the defect in the shaft is determined based on reflected ultrasonic signals corresponding to measurable features on the shaft.

17. The method of claim 12 wherein:

the ultrasonic signal is propagated along the length of the shaft by an ultrasonic transducer attached to an end of the shaft;

the ultrasonic transducer is operatively connected to a control unit for controlling a frequency and intensity of the ultrasonic signal propagated along the length shaft;

the ultrasonic transducer is operable to collect reflected ultrasonic signals, convert the reflected ultrasonic signals to electronic signals indicative of the reflected ultrasonic signals and pass the electronic signals to the control unit; and

the control unit is operable to receive the electronic signals from the ultrasonic transducer, store the electronic signals from the ultrasonic transducer in a memory and display the electronic signals on a display.

18. The method of claim 17 wherein the display is calibrated such that a position of a defect in the shaft may be determined based on the displayed electronic signals.

19. The method of claim 12 wherein the ultrasonic signal propagated along the length of the shaft has a frequency from about 0.1 MHz to about 50 MHz.

20. A system for inspecting a shaft for defects, the system comprising at least one shaft support, a tensioner, a rotational mechanism and an ultrasonic testing apparatus wherein:

the at least one shaft support is operable to receive the shaft and support the shaft as the shaft is rotated;

the tensioner is operable to apply a load to the shaft positioned in the at least one shaft support thereby causing the shaft to deflect;

the at least one rotational mechanism is operable to impart continuous rotational motion to the shaft when the shaft is positioned in the at least one shaft support; and

the ultrasonic testing apparatus comprises an ultrasonic transducer operatively coupled to a control unit wherein;

the ultrasonic transducer is attachable to an end of the shaft positioned in the at least one shaft support, the ultrasonic transducer being operable to propagate ultrasonic signals along a length of the shaft and receive reflected ultrasonic signals; and

the control unit is operable to control a frequency and intensity of the ultrasonic signals propagated by the ultrasonic transducer and store and display reflected ultrasonic signals received by the ultrasonic transducer.