SENSOR ASSEMBLY FOR BEARING WITH WIRELESS TEMPERATURE SENSOR

• US 20170030804A1
• Filed: 07/21/2016
• Published: 02/02/2017
• Est. Priority Date: 07/21/2015
• Status: Active Grant

• Current Assignee: ABet SKF
• Original Assignee: ABet SKF
• Inventors: de Wit, Frank, Lang, Defeng
• Granted Patent: US 9,964,465 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: F16C 2233/00 Monitoring condition, e.g. temperature, load, vibration
• CPC Class Codes: F16C 33/38 Ball cages
• CPC Class Codes: F16C 33/46 Cages for rollers or needles
• CPC Class Codes: F16C 41/00 Other accessories, e.g. devices integrated in the bearing not relating to the bearing function as such
• CPC Class Codes: F16C 41/004 Electro-dynamic machines, e.g. motors, generators, actuators
• CPC Class Codes: F16C 41/008 Identification means, e.g. markings, RFID-tags; Data transfer means
• CPC Class Codes: G01K 13/00 Thermometers specially adapted for specific purposes
• CPC Class Codes: G01K 7/36 using magnetic elements, e.g. magnets, coils magnetic elements per se H01F
• CPC Class Codes: G01M 13/04 Bearings

Abstract

The invention relates to a sensor assembly for use in a bearing including at least one bearing cage configured to accommodate at least one rolling element of the bearing, the sensor assembly including a driven oscillator circuit providing a receiver, a function generator and a primary coil, and a passive oscillator circuit including a temperature dependent capacitance. The passive oscillator circuit is configured to be attached to the bearing cage such that the inductor coil interacts with the primary coil of the driven oscillator circuit. It is proposed that a directional coupler is provided in a signal line between a function generator and the primary coil of the system, wherein the directional coupler is arranged to output a signal reflected from the passive resonant circuit in the cage toward a tuned receiver receiving the feedback of the signals generated by the function generator.

Claims

1. A sensor assembly used in a rolling element bearing including at least one bearing cage configured to accommodate at least one rolling element of the bearing, the sensor assembly comprising:

a driven oscillator circuit including a receiver, a function generator and a primary coil, and

a passive oscillator circuit including a temperature dependent capacitance, the passive oscillator circuit being configured to be attached to the bearing cage such that the inductor coil interacts with the primary coil of the driven oscillator circuit, wherein

a directional coupler is provided in a signal line between a function generator and the primary coil of the system, and wherein

the directional coupler is arranged to output a signal reflected from the passive resonant circuit in the cage toward a tuned receiver receiving the feedback of the signals generated by the function generator.

2. The sensor assembly according to claim 1, further comprising a transformer in a signal line having a coaxial cable between the directional coupler and the primary coil.

3. The sensor assembly according to claim 2, wherein the transformer is configured as a current mode balun.

4. The sensor assembly according to claim 1, further comprising a signal processing unit configured to analyze the signal received by the receiver.

5. The sensor assembly according to claim 4, wherein the signal processing unit is configured to calculate an average of the signal over a period sufficient for the cage to go through at least one revolution in relation to a non-rotating ring of the bearing.

6. The sensor assembly according to claim 1, further comprising an analogue-to-digital converter receiving an output of the receiver.

7. The sensor assembly according to claim 1, wherein both the primary coil and the inductor coil of the passive resonant circuit extend over the entire circumference of the bearing cage (10).

8. A bearing comprising:

a sensor assembly, the sensor assembly including least one bearing cage configured to accommodate at least one rolling element of the bearing,

a driven oscillator circuit including a receiver, a function generator and a primary coil, and

a passive oscillator circuit including a temperature dependent capacitance, the passive oscillator circuit being configured to be attached to the bearing cage such that the inductor coil interacts with the primary coil of the driven oscillator circuit,

wherein a directional coupler is provided in a signal line between a function generator and the primary coil of the system, and

wherein the directional coupler is arranged to output a signal reflected from the passive resonant circuit in the cage toward a tuned receiver receiving the feedback of the signals generated by the function generator.

9. A machine comprising:

a bearing equipped with a sensor device;

the sensor device providing a driven oscillator circuit including a receiver, a function generator and a primary coil, and

a passive oscillator circuit including a temperature dependent capacitance, the passive oscillator circuit being configured to be attached to the bearing cage such that the inductor coil interacts with the primary coil of the driven oscillator circuit, wherein

a directional coupler is provided in a signal line between a function generator and the primary coil of the system, and wherein

the directional coupler is arranged to output a signal reflected from the passive resonant circuit in the cage toward a tuned receiver receiving the feedback of the signals generated by the function generator.