Sensor and rolling bearing apparatus with sensor

• US 20030091253A1
• Filed: 11/30/2001
• Published: 05/15/2003
• Est. Priority Date: 12/01/2000
• Status: Active Grant

• Current Assignee: NSK Limited
• Original Assignee: NSK Limited
• Inventors: Endo, Shigeru, Takahashi, Toshio, Takizawa, Takeshi, Sakatani, Ikunori, Morita, Kouichi, Fukuyama, Hiromasa
• Granted Patent: US 6,695,483 B2
• Time in Patent Office: Days
• US Class Current: 384/448
• CPC Class Codes: B61F 15/20 Details
• CPC Class Codes: F16C 19/386 in O-arrangement
• 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 2326/10 Railway vehicles in general B61
• CPC Class Codes: F16C 33/723 Shaft end sealing means, e.g. cup-shaped caps or covers
• CPC Class Codes: F16C 35/063 Fixing them on the shaft with interposition of an element F16C35/07
• CPC Class Codes: F16C 41/007 Encoders, e.g. parts with a plurality of alternating magnetic poles
• CPC Class Codes: G01M 13/045 Acoustic or vibration analysis
• CPC Class Codes: G01P 1/026 for speed measuring devices, e.g. pulse generator
• CPC Class Codes: G01P 3/443 mounted in bearings bearings F16C
• CPC Class Codes: G01P 3/487 delivered by rotating magnets

Abstract

A rolling bearing apparatus with sensor includes a sensor unit retaining a plurality of types of sensors for detecting the status of a rolling bearing, in a single holder. The plurality of types of sensors are at least two types of sensors of a rotation speed sensor, a temperature sensor, and an acceleration sensor.

Claims

1. A rolling bearing apparatus with sensor comprising:

a sensor unit retaining a plurality of types of sensors in a single holder, said sensors detecting the status of a rolling bearing,

wherein the plurality of types of sensors are at least two types of sensors of a rotation speed sensor, a temperature sensor and a vibration sensor.

2. The rolling bearing apparatus according to claim 1, further comprising:

inner and outer rings rotating relative to each other such that one of said inner and outer rings is a rotating ring and the other is a stationary ring;

a plurality of rolling elements rotatably disposed between a raceway formed on an inner surface of said outer ring, and a raceway formed on an outer surface of said inner ring; and

an encoder supported on said rotating ring or a portion rotating together with said rotating ring, and rotating together with said rotating ring,

wherein said sensor unit is disposed close to said encoder in such a manner as to oppose said encoder, at said stationary ring or a portion supporting said stationary ring.

3. The rolling bearing apparatus according to claim 2, further comprising:

a nut disposed on an end of a shaft so as to position said inner ring in an axial direction of said shaft,

a housing being the portion supporting said stationary ring; and

a cover attached to said housing,

wherein said encoder is disposed between said inner ring and said nut in the axial direction or on an outer surface of said nut, and

wherein said sensor unit is attached to one of said housing and said cover.

4. The rolling bearing apparatus according to claim 1, wherein said sensor holder is made of one of austenite stainless steel, aluminum, magnesium copper, zinc, or an alloy of any of the same.

5. The rolling bearing apparatus according to claim 1, wherein each of signal lines extending from said sensors is twisted with a ground line, and said twisted signal lines are shielded individually.

6. The rolling bearing apparatus according to claim 1, wherein each of signal lines extending from said sensors is twisted with a ground line, and all of said twisted signal lines are collectively shielded.

7. The rolling bearing apparatus according to claim 1, wherein said temperature sensor is disposed on a leading end of said sensor holder of said sensor unit.

8. The rolling bearing apparatus according to claim 1, further comprising:

a reference voltage generation circuit located within said sensor holder for supplying a reference voltage to at least one of said temperature sensor and said vibration sensor.

9. The rolling bearing apparatus according to claim 1, wherein said temperature sensor is constructed by one of an NTC thermistor, a PTC thermistor, a CTR thermistor, a resistance temperature sensor, and an integrated circuit temperature sensor.

10. The rolling bearing apparatus according to claim 1, wherein said vibration sensor is constructed by one of a piezoelectric element and a strain gauge.

11. The rolling bearing apparatus according to claim 1, wherein outputs from at least one of said rotation speed sensor, said temperature sensor, and said vibration sensor are in the form of current.

12. The rolling bearing apparatus according to claim 1, further comprising:

a surge absorber protecting a sensor circuit from a surge voltage, for eliminating a noise.

13. The rolling bearing apparatus according to claim 1, further comprising:

a Zener diode protecting a sensor circuit from a surge voltage, for eliminating a noise.

14. The rolling bearing apparatus according to claim 1, further comprising:

an EMI filter for eliminating a noise.

15. The rolling bearing apparatus with a rotation speed sensor, comprising:

an encoder being constructed by alternately magnetizing a set of N pole, S pole and no pole or a set of S pole, N pole and no pole in a circumferential direction thereof, to thereby detect a rotating direction of said encoder by a single sensor.

16. A bearing apparatus with sensor comprising:

a rotation speed sensor detecting a rotation speed of a bearing;

a temperature sensor detecting a temperature of said bearing;

a threshold value setting device for setting a threshold value of temperature for abnormality detection on the basis of the rotation speed obtained by said rotation speed sensor;

a comparator comparing a temperature signal output from said temperature sensor with said threshold valve of temperature; and

an abnormality determining device determining an abnormality of said bearing on the basis of an output of said comparator.

17. A bearing apparatus with sensor comprising:

a rotation speed sensor detecting a rotation speed of a bearing;

a vibration sensor detecting a vibration of said bearing;

a threshold value setting device for setting a threshold value of vibration for abnormality detection on the basis of the rotation speed obtained by said rotation speed sensor;

a comparator comparing a vibration signal output from said vibration sensor with said threshold valve of vibration; and

an abnormality determining device determining an abnormality or said bearing on the basis of an output of said comparator.

18. The bearing apparatus with sensor according to claim 17, further comprising:

a variable filter through which said vibration signal output from said vibration sensor is passed, for changing a frequency to be eliminated or dampened, on the basis of said rotation speed detected by said rotation speed sensor,

wherein said comparator compares a signal output from said variable filter with said threshold value of vibration.

19. A bearing apparatus with sensor comprising:

a rotation speed sensor detecting a rotation speed of a bearing;

a vibration sensor detecting a vibration of said bearing;

a period analysis device performing a period analysis of a signal output from said vibration sensor; and

an abnormality determining device determining an abnormality of said bearing by analyzing a result of period analysis by use of a rotation speed signal output from said rotation speed sensor.

20. A bearing apparatus with sensor comprising:

a rotation speed sensor detecting a rotation speed of a bearing;

a vibration sensor detecting a vibration of said bearing;

an envelope processing device performing an envelope processing of a signal output from said vibration sensor so that said signal is subjected to a frequency analysis; and

an abnormality determining device determining an abnormality of said bearing by analyzing a result of frequency analysis by use of a rotation speed signal output from said rotation speed sensor.

21. A bearing apparatus with a temperature sensor for measuring a temperature of a bearing, comprising:

a thermistor built in said rolling bearing or in a vicinity thereof,

at least one of fixed resistors connected in parallel with said thermistor.

22. The bearing apparatus with a temperature sensor according to claim 21, wherein said temperature sensor has a negative temperature characteristic such that a sensor output drops in association with an increase in temperature, whereby said temperature sensor has a fail-safe function.

23. The bearing apparatus with a temperature sensor according to claim 21, wherein said thermistor is one of an NTC thermistor, a PTC thermistor, a CTR thermistor, and a silicon thermistor.

24. A bearing apparatus with a sensor for a bearing comprising:

a detecting section for detecting an object to be detected;

a circuit component for processing a detection signal output from said detecting section;

a circuit board on which said detecting section and said circuit component are mounted;

a fixing jig for fixing said circuit board; and

a sensor holder fixing said fixing jig.

25. The bearing apparatus with a sensor according to claim 24, wherein said fixing jig is fixed to said sensor holder by use of a jig fixing component.

26. The bearing apparatus with a sensor according to claim 24, wherein said fixing jig is fixed to said sensor holder by an adhesive after positioning said fixing jig therein.

27. A bearing apparatus with a sensor for a bearing comprising:

a detecting section for detecting an object to be detected;

a circuit component for processing a detection signal output from said detecting section;

a circuit board on which the detecting section and the circuit component are mounted; and

a noise shield connected to a reference voltage of the circuit.

28. The bearing apparatus with a sensor according to claim 27, wherein said noise shield further comprises at least one of:

a first noise shield connected to a reference voltage of circuit, and arranged in an annular manner on a surface of said circuit board having said detecting section and said circuit component so as to surround at least a part of said detecting section and said circuit component;

a second noise shield connected to a reference voltage of said circuit and arranged in a planar manner on a surface opposite to the surface of said circuit board having said detecting section and said circuit component so as to oppose and cover at least a region surrounded by said first noise shield, from the side opposite to said region; and

a case-like third noise shield connected to a reference voltage of said circuit and mounted on the surface of said circuit board having said detecting section and said circuit component so as to cover at least one of the detecting section and the circuit component.