State detection device, state detection method, state detection program, and information recording medium

• US 8,214,160 B2
• Filed: 01/31/2007
• Issued: 07/03/2012
• Est. Priority Date: 02/28/2006
• Status: Active Grant

• Current Assignee: THK Company Limited
• Original Assignee: THK Company Limited
• Inventors: Honjo, Yoshiyuki
• Primary Examiner(s): Teixeira Moffat, Jonathan C
• Assistant Examiner(s): PARK, HYUN D
• Application Number:
  US12/280,891
• Publication Number:
  US 20090205425A1
• Time in Patent Office: 1,980 Days
• Field of Search: 73/34
• US Class Current: 702/34
• CPC Class Codes: G01M 13/045 Acoustic or vibration analysis

Abstract

A state detecting apparatus S for detecting a current operating state of an LM (linear motion) system includes an AE sensor 1 generating a detection signal Sae by detecting an AE wave elastically generated when a plurality of balls contained in the LM system revolve in a circulation portion while spinning themselves; and a signal processing unit 4 generating a parameter indicating an intensity of the AE wave based on only the detection signal Sae corresponding to an operating frequency of the ball, and uses the parameter to determine a lubrication state of the LM system. Thereby, it is possible to provide the state detecting apparatus capable of predicting failure occurrence in the LM system; providing an improved maintenance to a user of the LM system and further longer lifetime thereof; and providing a performance guarantee and an improved quality of a device or equipment manufactured using the LM system.

Claims

1. A state detecting apparatus for detecting a current operating state of a linear motion rolling guide unit, the state detecting apparatus comprising:

an operating frequency obtain unit for obtaining an operating frequency of the linear motion rolling guide unit to be inspected;

a generated frequency of a noise signal obtain unit for obtaining a generated frequency of a noise signal which can be generated by a device other than the linear motion rolling guide unit to be inspected that is operating near the linear motion rolling guide unit;

a determination unit for determination of whether the operating frequency and the generated frequency of a noise signal are equal or not;

a detection unit for detecting a wave motion which is elastically generated due to at least one of collision which occurs between a rolling surface contained in the linear motion rolling guide unit and a rolling body when a plurality of rolling bodies contained in the linear motion rolling guide unit are revolving in a circulation portion while spinning themselves;

slip in a contact portion between the rolling surface and the rolling body;

collision between the rolling bodies themselves, slip in a contact portion of the rolling bodies themselves; and

crack which occurs in at least one of the rolling body and the rolling surface; and

for generating an electrical detection signal corresponding to the detected wave motion;

a transform device for configuring measured data group using individual measured data obtained by sampling the generated detection signal, performing Fourier transform on the measured data group, and generating a transformed measured value, respectively,

an extraction device for extracting only the transformed measured value corresponding to a frequency corresponding to an operating frequency of the linear motion rolling guide unit from the generated transformed measured values after performing the Fourier transform;

a generation device for generating a parameter indicating an intensity of the wave motion by adding data corresponding to an intensity of the transformed measure value to data corresponding to harmonic content of the operating frequency based on the extracted measured value as extracted; and

a determination device for comparing a value of the generated parameter and a threshold predetermined for the parameter and determining whether the operating state is normal or not.

2. The state detecting apparatus according to claim 1, wherein the extraction device outputs, to the generation device, the transformed measured value which is left by removing the transformed measured value corresponding to a frequency width equal to or greater than a frequency which is higher by a predetermined frequency width than an operating frequency of the linear motion rolling guide unit from the generated transformed measured values.

3. The state detecting apparatus according to claim 2, wherein the determination device determines that the operating state is a good lubrication state if a value of the generated parameter is less than the threshold.

4. A non-transitory computer readable medium containing a state detecting program, which when operated on a computer, causing a computer to function as the state detecting apparatus according to claim 2.

5. The state detecting apparatus according to claim 1, wherein the extraction device outputs, to the generation device, the transformed measured value which is left by removing the transformed measured value corresponding to a frequency width equal to or less than a frequency which is lower by a predetermined frequency width than an operating frequency of the linear motion rolling guide unit from the generated transformed measured values.

6. The state detecting apparatus according to claim 5, wherein the determination device determines that the operating state is a good lubrication state if a value of the generated parameter is less than the threshold.

7. The state detecting apparatus according to claim 1, wherein the determination device determines that the operating state is a good lubrication state if a value of the generated parameter is less than the threshold.

8. A non-transitory computer readable medium containing a state detecting program, which when operated on a computer, causing a computer to function as the state detecting apparatus according to claim 7.

9. A non-transitory computer readable medium containing a state detecting program, which when operated on a computer, causing a computer to function as the state detecting apparatus according to claim 1.

10. A non-transitory information recording medium, wherein the state detecting program according to claim 9 is computer-readably recorded by the computer.

11. A state detecting method for detecting a current operating state of a linear motion rolling guide unit, the state detecting method comprising:

an operating frequency obtain step for obtaining an operating frequency of the linear motion rolling guide unit to be inspected;

a generated frequency of a noise signal obtain step for obtaining a generated frequency of a noise signal which can be generated by a device other than the linear motion rolling guide unit to be inspected that is operating near the linear motion rolling guide unit;

a determination step, using a computer, for determination of whether the operating frequency and the generated frequency of a noise signal are equal or not;

a detection step for detecting a wave motion which is elastically generated due to at least one of collision which occurs between a rolling surface contained in the linear motion rolling guide unit and a rolling body when a plurality of rolling bodies contained in the linear motion rolling guide unit are revolving in a circulation portion while spinning themselves;

slip in a contact portion between the rolling surface and the rolling body;

collision between the rolling bodies themselves, slip in a contact portion of the rolling bodies themselves; and

crack which occurs in at least one of the rolling body and the rolling surface; and

for generating an electrical detection signal corresponding to the detected wave motion;

a transforming step for configuring measured data group using individual measured data obtained by sampling the generated detection signal, performing Fourier transform on the measured data group, and generating a transformed measured value, respectively,

an extraction step for extracting only the transformed measured value corresponding to a frequency corresponding to an operating frequency of the linear motion rolling guide unit from the generated transformed measured values after performing the Fourier transform;

a generation step for generating a parameter indicating an intensity of the wave motion by adding data corresponding to an intensity of the transformed measured value to data corresponding to harmonic content of the operating frequency based on the extracted measured value as extracted; and

a determination step for comparing a value of the generated parameter and a threshold predetermined for the parameter, and determining whether the operating state is normal or not.

12. The state detecting method according to claim 11, wherein the determination step for comparing the value determines that the operating state is a good lubrication state if a value of the generated parameter is less than the threshold.