Bearing condition monitoring method and apparatus

• US 20020105429A1
• Filed: 01/04/2002
• Published: 08/08/2002
• Est. Priority Date: 01/25/1999
• Status: Abandoned Application

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Foster, Robert Burke, Holtgrefe, James Earl, Donner, John Lawrence
• Application Number:
  US10/039,287
• Publication Number:
  US 20020105429A1
• Time in Patent Office: Days
• US Class Current: 340/682
• CPC Class Codes: B61K 9/04 Detectors for indicating the overheating of axle bearings and the like, e.g. associated with the brake system for applying the brakes in case of a fault
• CPC Class Codes: F16C 17/243 related to temperature and heat, e.g. for preventing overheating
• CPC Class Codes: F16C 19/525 related to temperature and heat, e.g. insulation
• CPC Class Codes: F16C 2233/00 Monitoring condition, e.g. temperature, load, vibration
• CPC Class Codes: F16C 2326/10 Railway vehicles
• CPC Class Codes: F16C 2361/61 Toothed gear systems, e.g. support of pinion shafts
• CPC Class Codes: F16C 33/6637 with liquid lubricant

Abstract

A method and apparatus for monitoring the condition of an oil lubricated bearing based on the phenomenon that the bearing will operate at a reduced temperature for a limited time period after losing its flow of lubricating oil. The invention includes steps and means for comparing the bearing temperature to an average of similar bearing temperatures, and for generating a low temperature alarm when the bearing temperature drops more than a threshold amount. The setpoint of this threshold may be a function of the standard deviation of the temperatures of a plurality of similar bearings. The invention may include steps and apparatus for generating a high bearing temperature alarm and for communicating data to a remote location.

Claims

1. A method of monitoring the loss of lubricant at each of a plurality of oil lubricated bearings, said method comprising:

continuously sensing the temperature of each of a plurality of bearings;

continuously computing a current average of said temperatures of said plurality of bearings;

determining when said bearing temperature sensed at any of said bearings drops below said current average of said bearing temperatures;

identifying which said bearing experiences such temperature drop; and

generating an alarm signal when the magnitude of said temperature drop of such identified bearing relative to said average of said bearing temperatures is greater than a selected threshold temperature difference, thereby warning of a loss of lubrication in said identified bearing, prior to the onset of bearing damage.

2. The method of claim 1, further comprising generating a second alarm signal when any one of said bearing temperatures first exceeds a predetermined threshold temperature.

3. The method of claim 1, further comprising displaying a visual alarm in response to said alarm signal.

4. The method of claim 1, further comprising sounding an audible alarm in response to said alarm signal.

5. The method of claim 1, further comprising:

continuously evaluating signals from a plurality of temperature sensors associated with said plurality of bearings to determine if any of said temperature sensors has failed to generate accurate temperature measurement signals; and

excluding said temperature measurement signals generated by any such failed temperature sensor from said computation of said current average of said temperatures and from said determination of bearing temperature drop.

6. The method of claim 1, further comprising:

continuously determining the highest current bearing temperature and the lowest current bearing temperature; and

excluding said highest current bearing temperature and said lowest current bearing temperature from said computation of said current average of said temperatures.

7. The method of claim 1, further comprising:

continuously computing the current standard deviation of said plurality of bearing temperatures; and

selecting said threshold temperature difference as a function of said current standard deviation of said plurality of temperatures.

8. A method of monitoring the loss of lubricant from oil lubricated bearings in the traction motors of a locomotive prior to the onset of bearing damage, the method comprising:

providing a temperature sensor on each of a plurality of bearings;

continuously generating a temperature signal with each said sensor, each said signal being indicative of the current sensed operating temperature of one of said bearings;

communicating said temperature signals to a processor;

processing said temperature signals at said processor to continuously convert each said temperature signal to said current sensed bearing operating temperature, and to continuously calculate a current average of said sensed operating temperatures of said bearings;

determining when said sensed bearing operating temperature at any of said bearings drops below said current average of said sensed bearing operating temperatures;

identifying which said bearing experiences such temperature drop; and

generating an alarm signal when the magnitude of said temperature drop of such identified bearing relative to said current average of said bearing temperatures is greater than a selected threshold temperature difference, thereby warning of a loss of lubrication in said identified bearing, prior to the onset of bearing damage.

9. The method of claim 8, wherein said threshold temperature difference is selected to be 20 Celsius degrees.

10. The method of claim 8, further comprising:

operating said processor to continuously compute the current standard deviation of said sensed bearing operating temperatures; and

operating said processor to select said threshold temperature difference as a function of said standard deviation of said sensed bearing operating temperatures.

11. The method of claim 8, further comprising operating said processor to generate an alarm signal when any of said sensed bearing operating temperatures first exceeds a predetermined threshold temperature.

12. The method of claim 11, wherein said predetermined threshold temperature is selected to be 150 degrees Celsius.

13. The method of claim 8, further comprising:

operating said processor to continuously determine the highest current sensed bearing operating temperature and the lowest current sensed bearing operating temperature; and

excluding said highest current sensed bearing operating temperature and said lowest current sensed bearing operating temperature from said computation of said current average of said sensed bearing operating temperatures.

14. The method of claim 8, further comprising the step of communicating said alarm signal off-board of said locomotive.

17. The apparatus of claim 16, further comprising a signal generator adapted to generate an alarm signal when any one of said current bearing temperatures exceeds a predetermined threshold temperature.

15. A method of monitoring the loss of lubricant at each of a plurality of oil lubricated bearings prior to the onset of bearing damage, said method comprising:

continuously sensing the temperature of each of a plurality of bearings with a plurality of temperature sensors, each said sensor being associated with one of said plurality of bearings;

continuously evaluating signals from said plurality of temperature sensors to determine if any of said temperature sensors has failed to generate accurate temperature measurement signals;

identifying the temperature currently sensed by any said failed temperature sensor as an invalid temperature, with the remaining bearing temperatures being considered to be valid bearing temperatures;

continuously computing a current average of said valid temperatures of said plurality of bearings;

determining when the bearing temperature sensed at any of said bearings drops below said current average of said valid bearing temperatures;

identifying which bearing experiences such temperature drop;

continuously computing the current standard deviation of said plurality of valid bearing temperatures;

continuously selecting a threshold temperature difference as a function of said current standard deviation of said plurality of valid temperatures; and

generating an alarm signal when the magnitude of said temperature drop of said identified bearing relative to said average of bearing temperatures is greater than said selected threshold temperature difference, thereby warning of a loss of lubrication in said identified bearing, prior to the onset of bearing damage.

16. An apparatus for monitoring the loss of lubricant at each of a plurality of oil lubricated bearings prior to the onset of bearing damage, the apparatus comprising:

a plurality of temperature sensors, each said sensor being adapted to generate a temperature signal indicative of the current temperature of one of a plurality of bearings;

a processor adapted to receive said plurality of temperature signals and programmed to continuously calculate a current average of said current bearing temperatures;

circuitry adapted to determine when said bearing temperature sensed at any of said bearings drops below said current average of said bearing temperatures;

circuitry adapted to identify which bearing experiences such temperature drop; and

a signal generator adapted to generate an alarm signal when the magnitude of said temperature drop of such identified bearing relative to said average of said bearing temperatures is greater than a selected threshold temperature difference, thereby warning of the loss of lubrication in said identified bearing, prior to the onset of bearing damage.