Rotary Transducer with Monitoring of the Bearing Wear and Method Therefor

• US 20100180664A1
• Filed: 06/20/2008
• Published: 07/22/2010
• Est. Priority Date: 07/31/2007
• Status: Active Grant

• Current Assignee: Baumer Germany GmbH & Company KG
• Original Assignee: Baumer Huebner GmbH
• Inventors: Wilhelmy, Lothar, Wilhelmy, Jochen, Hiller, Bernhard
• Granted Patent: US 8,539,811 B2
• Time in Patent Office: Days
• US Class Current: 73/7
• CPC Class Codes: F16C 19/52 with devices affected by abnormal or undesired conditions
• 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 41/007 Encoders, e.g. parts with a plurality of alternating magnetic poles
• CPC Class Codes: G01D 3/08 with provision for safeguarding the apparatus, e.g. against abnormal operation, against breakdown
• CPC Class Codes: G01M 13/04 Bearings
• CPC Class Codes: G01P 21/02 of speedometers
• CPC Class Codes: G01P 3/481 of pulse signals

Abstract

The invention relates to a rotary transducer (1) and to a method for monitoring wear on the latter. The rotary transducer has a detector device (11) having at least one measurement sensor (12). During operation, the measurement sensor can be used to generate a measurement signal (13) which is representative of the angular position and/or velocity of an object which can be connected to the rotary transducer. The detector device (11) has at least one rotary bearing (15) and at least one material measure (16) which can be rotated, by means of the rotary bearing, relative to the measurement sensor and is arranged in the measurement field (17) of the latter. A monitoring device (20) which is connected to the measurement sensor such that data are transmitted and can be used, during operation, to output a state signal (23), which is representative of the state of wear of the rotary transducer, on the basis of the measurement signal is also integrated in the rotary transducer (1). In order to be able to warm of mechanical failure of the rotary transducer in good time, the monitoring device (20) is provided, according to the invention, with a register (25) which can permanently store a value which is representative of the state of wear of the rotary bearing and is formed form the information relating to the angular position and/or velocity which is contained in the measurement signal.

Claims

1. A rotary encoder having integrated therein a detector device comprising at least one measurement sensor by which, during operation, a measurement signal can be generated that is representative of the angular position and/or velocity of an object which is connectable to the rotary encoder, at least one rotary bearing, and at least one material measure which is arranged rotatable relative to the measurement sensor in the measurement field thereof by means of the rotary bearing, and a monitoring device which is connected to the measurement sensor such that data are transmitted, wherein the monitoring device comprises a counter which can permanently store a value which is representative of the state of wear of the rotary bearing and is formed from the information contained in the measurement signal on the angular position and/or velocity.

2. The rotary encoder according to claim 1, wherein the rotary encoder comprises a housing in which the detector device and the monitoring device are accommodated.

3. The rotary encoder according to claim 1, wherein the counter comprises a non-volatile electronic memory.

4. The rotary encoder according to claim 1, wherein the counter comprises an adder in which at least during operation a revolution number formed from the measurement signal can be added up.

5. The rotary encoder according to claim 1, wherein the monitoring device comprises a comparator by which a value of the revolution number stored in the counter can be compared with a predeterminable limit value.

6. The rotary encoder according to claim 1, wherein the rotary encoder has integrated therein at least one temperature sensor by which a temperature representative of the rotary bearing can be sensed.

7. The rotary encoder according to claim 1, wherein the rotary encoder has integrated therein a structure-borne sound sensor by which a structure-borne sound produced by the rotary bearing during operation can be sensed.

8. A method for monitoring wear of a rotary encoder which during operation senses the angular position and/or velocity of a rotating object connected to the rotary encoder and outputs it as a measurement signal, wherein a state variable representative of the wear condition of a rotary bearing of the rotary encoder is monitored on the basis of the information contained in the measurement signal on the angular position and/or velocity, and a state signal representative of the functional state of the rotary bearing is output by the rotary encoder.

9. The method according to claim 8, wherein the rotary encoder adds up the revolutions independently of the rotary direction as a state variable.

10. The method according to claim 9, wherein the rotary encoder directly provides the added-up number of revolutions as a state signal.

11. The method according to claim 8, wherein the rotary encoder internally senses the temperature of the rotary bearing as a state variable.

12. The method according to claim 8, wherein the rotary encoder internally senses the vibrations of the rotary bearing as a state variable.

13. The method according to claim 8, wherein the rotary encoder directly determines, on the basis of the measurement signal, the number of revolutions of the rotary bearing performed since the start of operation.

14. The method according to claim 8, wherein the rotary encoder compares the state variable with a previously stored value and generates the state signal in response to the result of said comparison.

15. The method according to claim 14, wherein the rotary encoder outputs the state signal whenever a residual life calculated on the basis of the state variable falls below a stored residual life.

16. The method according to claim 15, wherein the rotary encoder takes into account the life of the rotary bearing in a reducing way if the angular velocity determined from the measurement signal is below a first stored limit velocity and/or above a second stored limit velocity.

17. The method according to claim 16, wherein the rotary encoder takes into account the life of the rotary bearing in a reducing way if the monitored temperature is below a first stored limit temperature and/or above a second stored limit temperature.

18. The method according to claim 15, wherein the rotary encoder takes into account the life of the rotary bearing in a reducing way if the amplitude of the monitored vibrations are above a stored limit value.

19. The method according to claim 8, wherein in the rotary encoder the time progression of the at least one state variable is stored to be readable from outside the rotary encoder.

20. The method according to claim 8, wherein the rotary encoder monitors the function of the detector device and/or the monitoring device and outputs a state signal representative of the functional state thereof.

21. The method according to claim 20, wherein an alarm signal which is representative of a faulty operative state is output when during monitoring of the wear state the limit life is passed and/or the state signal representative of the function monitoring represents a malfunction.

22. The method according to claim 8, wherein, when an alarm limit value is exceeded by a monitored state variable, an alarm signal is output independently of the values of the other monitored state variables.