MOTOR BRAKE SYSTEM

• US 20190101175A1
• Filed: 09/29/2017
• Published: 04/04/2019
• Est. Priority Date: 09/29/2017
• Status: Active Grant

• Current Assignee: Rockwell Automation Technologies Incorporated (Allen-Bradley Co., Inc.)
• Original Assignee: Rockwell Automation Technologies Incorporated (Allen-Bradley Co., Inc.)
• Inventors: Chandrasekara, Chetan, Guru, Arun K.
• Granted Patent: US 10,520,054 B2
• Time in Patent Office: Days
• CPC Class Codes: F16D 2055/0033 Fully-enclosing housings
• CPC Class Codes: F16D 2066/003 Position, angle or speed
• CPC Class Codes: F16D 2066/005 Force, torque, stress or strain
• CPC Class Codes: F16D 2121/22 for releasing a normally applied brake
• CPC Class Codes: F16D 49/02 shaped as a helical band or coil with more than one turn, with or without intensification of the braking force by the tension of the band or contracting member similar clutches F16D13/08
• CPC Class Codes: F16D 65/186 with full-face force-applying member, e.g. annular
• CPC Class Codes: F16D 66/02 Apparatus for indicating wear
• CPC Class Codes: F16D 66/024 Sensors mounted on braking members adapted to contact the brake disc or drum, e.g. wire loops severed on contact
• CPC Class Codes: G01L 5/28 for testing brakes
• CPC Class Codes: G01M 13/028 Acoustic or vibration analysis
• CPC Class Codes: G01M 7/00 Vibration-testing of structures; Shock-testing of structures G01M9/00 takes precedence
• CPC Class Codes: G05B 2219/41279 Brake

Abstract

A motor includes a brake diagnostics system with sensors to assess the brake assembly condition. Acoustic or other vibration sensors provide vibration data that is compared to known vibration spectrum data to compare the condition of the brake assembly to a properly functioning brake assembly. The brake diagnostics system monitors current flow in the brake coil to assess the condition of the brake assembly. The sensed brake coil current is compared to known coil current spectrum data to compare the condition of the brake assembly to a properly functioning brake assembly. The voltage input to the brake coil is varied depending upon the current sensed in the brake coil to minimize heat in the brake coil. The motor also includes a resilient layer of thermally conductive material located between the brake assembly and the housing that provides a continuous, uninterrupted thermal pathway between the brake assembly and the motor housing.

Claims

1. A motor comprising:

a housing including a rotor and stator;

a brake assembly adapted to restrain rotation of the rotor;

a brake controller comprising a brake diagnostics system;

at least one vibration sensor located in the housing and providing vibration data to the brake diagnostics system in response to a brake operation cycle of the brake assembly, wherein said vibration data is used by the brake diagnostics system to assess an operative condition of the brake assembly.

2. The motor as set forth in claim 1, wherein:

said brake diagnostics system comprises a stored normal vibration spectrum for a brake operation cycle, said stored normal vibration spectrum representing vibration of said motor over time during said brake operation cycle for a brake assembly in a first operative condition; and

,

said brake diagnostics system compares said vibration data received to said stored normal vibration spectrum to determine the operative condition of said brake assembly.

3. The motor as set forth in claim 1, wherein said brake diagnostics system compares said vibration data received to a plurality of stored vibration spectrum patterns using pattern matching, and wherein said brake diagnostics system determines the operative condition of the brake assembly based upon a closest match between the vibration data received and one of said plurality of stored vibration spectrum patterns.

4. The motor as set forth in claim 1, wherein said vibration data received by the brake diagnostics system represents at least a start of the brake operation cycle and at least an end of the brake operation cycle, and wherein said brake diagnostics system determines an actual brake cycle time defined by a length of time between said start and said end of the brake operation cycle and said brake diagnostics system compares the actual brake cycle time to a stored brake cycle time to determine the operative condition of the brake assembly.

5. The motor as set forth in claim 4, wherein said operative condition of the brake assembly is determined by the brake diagnostics system to be worse that a normal operative condition of the brake assembly if the actual brake cycle time is greater than the stored brake cycle time.

6. The motor as set forth in claim 1, wherein said vibration data received by the brake diagnostics system represents at least a start of the brake operation cycle and at least an end of the brake operation cycle, and wherein said brake diagnostics system determines an actual brake cycle time defined by a length of time between said start and said end of the brake operation cycle and said brake diagnostics system compares the actual brake cycle time to a previous actual brake cycle time determined by the brake diagnostics system to assess the operative condition of the brake assembly.

7. The motor as set forth in claim 6, wherein said operative condition of the brake assembly is determined by the brake diagnostics system to be worse that a normal operative condition of the brake assembly if the actual brake cycle time is greater than the previous actual brake cycle time by more than a select percentage.

8. The motor as set forth in claim 1, wherein said brake assembly comprises a brake coil, and wherein said motor further comprises a brake coil current feedback system operatively associated with the brake coil and adapted to sense electrical current flowing through the brake coil.

9. The motor as set forth in claim 8, wherein said brake coil current feedback system provides a coil current feedback signal to said brake diagnostics system, wherein a magnitude of coil current feedback signal indicates a magnitude of the electrical current flowing through the brake coil.

10. The motor as set forth in claim 9, wherein said brake controller varies a voltage input to the brake coil in response to said magnitude of the coil current feedback signal.

11. The motor as set forth in claim 10, wherein said brake controller reduces the voltage input to the brake coil when said coil current feedback signal indicates that the magnitude of electrical current flowing through the brake coil is greater than a minimum holding current value required to maintain the brake assembly in a disengaged position.

12. The motor as set forth in claim 9, wherein the brake diagnostics system compares the coil current feedback signal to at least one stored brake coil current value to determine the operative condition of the brake assembly.

13. The motor as set forth in claim 12, wherein the brake diagnostics system compares the coil current feedback signal to at least one of:

(i) a stored brake coil current maximum value; and

, (ii) a stored brake coil current minimum value.

14. The motor as set forth in claim 12, wherein:

said brake diagnostics system includes a stored ideal coil current spectrum that indicates a preferred coil current magnitude flowing in the brake coil at different times during a brake operation cycle to disengage the brake assembly when the brake assembly is in a first operative condition; and

,

the brake diagnostics system compares the coil current feedback signal to the stored ideal current spectrum to determine the operative condition of the brake assembly.

15. The motor as set forth in claim 14, wherein the brake diagnostics signal determines that the brake assembly is in a second operative condition that differs from the first operative condition when the coil current feedback signal differs from the stored ideal coil current spectrum.

16. The motor as set forth in claim 1, further comprising at least one direct brake sensor associated with the brake assembly for directly measuring at least one operating parameter of the brake assembly, wherein said at least one direct brake sensor comprises at least one of a temperature sensor, a vibration sensor, a position sensor, a movement sensor, a pressure sensor.

17. The motor as set forth in claim 1, wherein said vibration sensor comprises an acoustic sensor and said vibration data comprises acoustic data, and wherein the acoustic data is used by the brake diagnostics system to assess an operative condition of the brake assembly.

18. A motor comprising:

a housing including a rotor and stator;

a brake assembly adapted to restrain rotation of the rotor, said brake assembly comprising a brake coil;

a brake controller comprising a brake diagnostics system;

a brake coil current feedback system operatively associated with the brake coil and adapted to sense electrical current flowing through the brake coil, wherein said brake coil current feedback system provides a coil current feedback signal to the brake diagnostics system, and wherein a magnitude of coil current feedback signal indicates a magnitude of the electrical current flowing through the brake coil.

19. The motor as set forth in claim 18, wherein said brake diagnostics system uses the magnitude of the coil current feedback signal to at least one of:

(i) determine an operative condition of the brake assembly based upon the magnitude of the coil current feedback signal during a brake operation cycle;

(ii) reduce a voltage input to the brake coil when the coil current feedback signal indicates that more than a minimum holding current is flowing in the brake coil, wherein said minimum holding current represents a minimum current magnitude flowing in the brake coil required to maintain the brake assembly in a disengaged state.

20. A motor comprising:

a housing including a rotor and stator;

a brake assembly adapted to restrain rotation of the rotor;

a resilient layer of thermally conductive material located between the brake assembly and the housing of the motor, said resilient layer of thermally conductive material providing a continuous, uninterrupted thermal pathway between the brake assembly and the motor housing.