Computerized electronic runout

• US 20040015326A1
• Filed: 07/19/2002
• Published: 01/22/2004
• Est. Priority Date: 07/19/2002
• Status: Active Grant

• Current Assignee: Ansaldo Energia IP UK Limited (Ansaldo Energia SPA)
• Original Assignee: Alstom Technology Ltd. (Alstom SA)
• Inventors: Bluestein, Keith
• Granted Patent: US 6,757,636 B2
• Time in Patent Office: Days
• US Class Current: 702/155
• CPC Class Codes: G01M 1/22 and converting vibrations due to imbalance into electric variables
• CPC Class Codes: G01M 1/24 Performing balancing on elastic shafts, e.g. for crankshafts

Abstract

A system and method for measuring the radial runout of a shaft, rotatably supported on a standard rest, includes at least a first journal surface sensing assembly, a second journal surface sensing assembly, and a test surface sensing assembly which sense the radial position of the first journal surface, the second journal surface, and a test portion of the shaft, respectively, during rotation of the shaft. A transmitter of each surface sensing assembly transmits a runout signal which is received by a receiver of a computer. Within the computer, the runout signal from the test surface sensing assembly is adjusted with the runout signals from the first and second journal surface sensing assemblies to factor out deflection of the shaft caused by the standard rest and the shaft runout is computed and plotted using the normalized runout data.

Claims

1. A system for measuring the runout of a shaft rotatably supported on a standard rest, the shaft extending longitudinally from a first end to a second end and having an outer surface, a coupling, a first journal surface, and a second journal surface, the system comprising:

a plurality of surface sensing assemblies including at least a first journal surface sensing assembly, a second journal surface sensing assembly, and a test surface sensing assembly adapted for sensing the first journal surface, the second journal surface, and a test portion of the outer surface positioned at a location other than the first and second journal surfaces, respectively, each of the surface sensing assemblies having a surface sensor and a transmitter in electrical communication with the surface sensor, the surface sensor being adapted for continuously sensing the radial position of the associated surface of the shaft and

a computer including a receiver, a memory in electrical communication with the receiver, a test operating system stored in the memory, a normalization program stored in the memory, and a runout spreadsheet program stored in the memory, the runout spreadsheet program having a plurality of data cells adapted for storing runout data and a plurality of operator cells storing formulas and instructions for operating on the data stored in the data cells;

wherein during rotation of the shaft, the transmitter of each surface sensing assembly transmits a runout signal proportional to the runout of the associated surface, the computer receiver receives the runout signals transmitted by the surface sensing assemblies, the test operating system applies the normalization program to compute normalized runout data by adjusting the runout signal from the test surface sensing assembly with the runout signals from the first and second journal surface sensing assemblies to factor out deflection of the shaft caused by the standard rest, the test operating system inserts the normalized runout data into predetermined data cells of the runout spreadsheet, and the formulas and instructions stored in the operator cells of the runout spreadsheet compute and plot the shaft runout.

2. The system of claim 1 further comprising a magnetic field sensing device and a plurality of magnets, the magnets being adapted for mounting at radially spaced positions on the shaft coupling, the magnetic field sensing device having a magnetic field sensor disposed proximate to the shaft and a transmitter in electrical communication with the magnetic field sensor, the magnetic field sensing device transmits an initiation signal each time a one of the magnets passes the magnetic field sensor.

3. The system of claim 2 wherein each of the surface sensing assemblies also includes a receiver and the computer also includes a transmitter, the test operating system causing the computer transmitter to transmit a data request signal each time the computer receiver receives a one of the initiation signals and the transmitter of each surface sensing assembly transmitting a discrete runout signal on receipt of a data request signal by the receiver of the surface sensing assembly.

4. The system of claim 3 wherein the magnetic field sensing device and each of the surface sensing assemblies also includes a power source.

5. The system of claim 1 wherein each of the surface sensing assemblies also includes a signal processor electrically disposed intermediate the surface sensor and the transmitter.

6. A system for measuring the runout of a shaft rotatably supported on a standard rest, the shaft extending longitudinally from a first end to a second end and having an outer surface, a coupling, a first journal surface, and a second journal surface, the system comprising:

a plurality of surface sensing assemblies including at least a first journal surface sensing assembly, a second journal surface sensing assembly, and a test surface sensing assembly adapted for sensing the first journal surface, the second journal surface, and a test portion of the outer surface positioned at a location other than the first and second journal surfaces, respectively, each of the surface sensing assemblies having a surface sensor and a transceiver in electrical communication with the surface sensor, the surface sensor being adapted for continuously sensing the radial position of the associated surface of the shaft;

a plurality of magnets adapted for mounting at radially spaced positions on the shaft coupling;

a magnetic field sensing device including a magnetic field sensor disposed proximate to the shaft coupling and a transmitter in electrical communication with the magnetic field sensor; and

a computer including a transceiver, a memory in electrical communication with the transceiver, a test operating system stored in the memory, a normalization program stored in the memory, and a runout spreadsheet program stored in the memory, the runout spreadsheet program having a plurality of data cells adapted for storing runout data and a plurality of operator cells storing formulas and instructions for operating on the data stored in the data cells;

wherein during rotation of the shaft, the magnetic field sensing device transmits an initiation signal each time a one of the magnets passes the magnetic field sensor, the test operating system causes the computer to transmit a data request signal each time the computer receives a one of the initiation signals, each surface sensing assembly transmits a discrete runout signal proportional to the runout of the associated surface on receipt of a data request signal, the test operating system applies the normalization program to compute normalized runout data by adjusting the runout signal from the test surface sensing assembly with the runout signals from the first and second journal surface sensing assemblies to factor out deflection of the shaft caused by the standard rest, the test operating system inserts the normalized runout data into predetermined data cells of the runout spreadsheet, and the formulas and instructions stored in the operator cells of the runout spreadsheet compute and plot the shaft runout.

7. The system of claim 6 wherein the magnetic field sensing device and each of the surface sensing assemblies also includes a power source.

8. The system of claim 6 wherein each of the surface sensing assemblies also includes a signal processor electrically disposed intermediate the surface sensor and the transmitter.

9. A method for measuring the runout of a shaft rotatably supported on a standard rest, the shaft extending longitudinally from a first end to a second end and having an outer surface, a coupling, a first journal surface, and a second journal surface, the method comprising the steps of:

A) attaching a plurality magnets at radially equidistantly spaced points on the shaft coupling;

B) positioning a magnetic field sensor of a magnetic field sensing device proximate to the shaft coupling whereby the magnets are rotatable through a sensing field of the magnetic field sensor with out contacting the magnetic field sensor;

C) positioning a surface sensor of a first journal surface sensing assembly and a surface sensor of a second journal surface sensor assembly for sensing the first and second journal surfaces of the shaft, respectively;

D) positioning a surface sensor of a test surface sensing assembly for sensing a test surface portion of the shaft;

E) rotating the shaft, the surface sensing assemblies continuously sensing the radial position of the associated surface of the shaft;

F) initiating a test run;

G) transmitting an initiation signal from a transmitter of the magnetic field sensing device each time a one of the magnets rotates past the magnetic field sensor;

H) transmitting a data request signal from a transceiver of a computer each time the transceiver of the computer receives an initiation signal;

I) transmitting a discrete runout signal from a transceiver of each of the surface sensing assemblies each time the transceiver of the surface sensing assembly receives a data request signal;

J) receiving the discrete runout signals at the computer and normalizing the runout signal from the test surface sensing assembly to factor out deflection of the shaft caused by the standard rest;

K) inserting the normalized runout signals into predetermined data cells of a runout spreadsheet stored in memory of the computer; and

L) computing and plotting runout with the runout spreadsheet.

10. The method of claim 9 wherein step (F) comprises the sub-steps of entering test parameters into a test operating system stored in the memory of the computer, the test parameter including the number (N_M) of magnets mounted on the shaft coupling and the longitudinal location (D_n, D_L, D_R) on the shaft of each surface sensing assembly.

11. The method of claim 10 further comprising the step of M) determining whether runout testing has been completed.

12. The method of claim 11 wherein step (M) comprises the sub-steps of:

1) logically determining whether the test run has been completed by

i) keeping a running total of the number of initiation signals received from the magnetic field sensing device since step (F),

ii) determining that the test run has been completed when N_M equals the initiation signal running total, and

2) determining whether the shaft runout has been measured at a sufficient number of test surface portions of the shaft.

13. The method of claim 12 wherein steps (D) through (M) are repeated, with the surface sensor of the test surface sensing assembly being moved to sense a different test portion of the shaft, if it is determined that runout testing has not been completed.

14. The method of claim 12 further comprising the step of N) printing runout report, if it is determined that runout testing has been completed.

15. The method of claim 9 wherein during step (J), the discrete runout signal is normalized utilizing the relationship:

{circumflex over (R)}_n=R_n−

(1−

((D_n−

D_L)/(D_R−

D_L)))R_L+((D_n−

D_L)/(D_R−

D_L))R_R

wherein R_n is the normalized runout signal of the test surface sensing assembly, R_L is the runout signal from the first journal surface sensing assembly, and R_R is the runout signal from the second journal surface sensing assembly.

16. A method for measuring the runout of a shaft rotatably supported on a standard rest, the shaft extending longitudinally from a first end to a second end and having an outer surface, a coupling, a first journal surface, and a second journal surface, the method comprising the steps of:

A) positioning a surface sensor of a first journal surface sensing assembly, a surface sensor of a second journal surface sensor assembly, and a surface sensor of a test surface sensing assembly for sensing the first journal surface of the shaft, the second journal surfaces of the shaft, and a test surface portion of the shaft, respectively;

B) rotating the shaft, the surface sensing assemblies continuously sensing the radial position of the associated surface of the shaft;

C) initiating a test run;

D) transmitting a runout signal from each of the surface sensing assemblies;

E) receiving the runout signals at the computer and normalizing the runout signal from the test surface sensing assembly to factor out deflection of the shaft caused by the standard rest;

F) computing and plotting the shaft runout.

17. The method of claim 16 further comprising the step of G) dividing the runout signals from the surface sensing assemblies into discrete segments prior to normalizing the runout signal from the test surface sensing assembly.

18. The method of claim 17 wherein step (F) comprises the sub-steps of:

1) inserting the normalized runout signal segments into predetermined data cells of a runout spreadsheet stored in memory of the computer; and

2) computing and plotting runout with the runout spreadsheet.