JP2007212160A - Lubricant deterioration detecting device, and bearing equipped with detecting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lubricant deterioration detecting device capable of stably detecting the degradation state of lubricant without influence of a change in thickness/temperature of the lubricant with a high degree of freedom of arrangement into a bearing, and the bearing equipped with the lubricant degradation detecting device. <P>SOLUTION: This lubricant degradation detecting device 1 comprises a light source 2, a plurality of light detecting elements 3 which detect the transmitted light emitted from the light source 2 and transmitted through the lubricant 6, and a determination means 4. The plurality of detection elements 3 have light detecting surface locations which are sequentially shifted to each other. The determination means 4 detects the degradation state of the lubricant 5 by comparing output signal strengths of the plurality of light detecting elements 3. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a lubricant deterioration detection device for detecting a deterioration state due to a contaminant of a lubricant, and a bearing with a detection device provided with the lubricant deterioration detection device, for example, for railway vehicles, automobiles, industrial machinery, etc. The present invention relates to a bearing with a detection device.

  In a bearing in which a lubricant is enclosed, if the lubricant (grease, oil, etc.) inside the bearing deteriorates, the rolling element will be poorly lubricated and the bearing life will be shortened. Judging the poor lubrication of the rolling elements from the vibration state of the bearing, etc., will be dealt with after an operational abnormality occurs due to the end of the life, so the abnormality of the lubricating state cannot be detected earlier. Therefore, it is desired to observe the state of the lubricant in the bearing periodically or in real time so that the abnormality or the maintenance period can be predicted.

As a major factor in the deterioration of the lubricant, wear powder generated with use of the bearing is mixed into the lubricant.
A sensor-equipped bearing in which a sensor such as an electrode or a coil is arranged inside the seal of the bearing so that the electrical characteristics of the lubricant mixed with wear powder can be detected by the sensor. Has been proposed (for example, Patent Document 1).
JP 2004-293776 A

  However, the sensor-equipped bearing of Patent Document 1 is for detecting the electrical characteristics of the lubricant. Therefore, unless a situation occurs such that a large amount of wear powder enters and conduction occurs, it is not detected as a characteristic change. Detection of contaminants may be difficult.

  In order to solve such a problem, for example, as shown in FIG. 8, a lubricant 35 is interposed between the light emitting element 33 and the light receiving element 34 arranged so as to face each other, and light emitted from the light emitting element 33 and transmitted through the lubricant 35. An optical configuration is considered in which the deterioration state of the lubricant 35 is estimated from the amount of light detected by the light receiving element 34.

  However, in the case of this configuration, when the thickness d of the lubricant 35 to be detected changes as indicated by a broken line in the figure, the amount of light detected by the light receiving element 34 changes. It is necessary to have a configuration that keeps constant.

Therefore, for example, as shown in FIG. 9, one end of each of the optical fibers 36 and 37 on the light emitting side and the light receiving side is opposed to the measuring unit 38 in which the lubricant 35 to be detected exists, and the other end of the optical fiber 36 on the light emitting side. A configuration in which the light emitting element 33 and the light receiving element 34 are arranged on the other end of the light receiving side optical fiber 37 is considered.
In the configuration of FIG. 9, the light emitted from the light emitting element 33 passes through the lubricant 35 present in the measuring unit 38 via the light emitting side optical fiber 36, and further receives light via the light receiving side optical fiber 37. The amount of foreign matter mixed in the lubricant 35 is estimated from the amount of transmitted light detected by the element 34 and detected by the light receiving element 34. In this case, since the area facing the optical fibers 36 and 37 in the measurement unit 38 can be reduced, the lubricant 35 can easily enter the measurement unit 38, and the lubricant 35 entering the measurement unit 38 is easily maintained at a constant thickness. be able to.

  However, even in the case of the configuration of FIG. 9, a measuring unit 38 having a container structure in which the lubricant 35 is maintained at a constant thickness d is necessary, and for example, it is used for detecting deterioration of the lubricant enclosed in the bearing. In this case, the degree of freedom of arrangement inside the bearing is reduced.

  An object of the present invention is to provide a lubricant deterioration detection device that has a high degree of freedom in arrangement inside a bearing and the like, and that can stably detect the deterioration state of the lubricant without being affected by changes in the thickness or temperature of the lubricant, and its To provide a bearing with a detection device provided with a lubricant deterioration detection device.

The lubricant deterioration detection device of the present invention includes a light source and a plurality of light detection elements that detect transmitted light emitted from the light source and transmitted through the lubricant, and the plurality of light detection elements are provided on a light detection surface. The position is sequentially shifted from each other, and determination means for detecting the deterioration state of the lubricant is provided by comparing the signal intensities of the outputs of the plurality of light detection elements.
As described above, in this lubricant deterioration detection device, a plurality of light detection elements are arranged in, for example, a line in which the positions of the light detection surfaces are sequentially shifted from each other, and the signal intensity of the outputs of the plurality of light detection elements is determined. Since the deterioration state of the lubricant is detected by means of comparison, the thickness of the lubricant itself and the intensity of the light source can be detected by arranging multiple light detection elements in the lubricant for detection. The deterioration state of the lubricant can be detected without being affected by the distance from the light source to the light detection element.
As a result, even when the lubricant deterioration detection device is installed inside the bearing or the like, the degree of freedom of arrangement becomes high, and a configuration that matches the installation space restriction is possible. Since the deterioration state of the lubricant is detected by comparing the signal intensities of the outputs of the plurality of light detection elements, stable detection is possible without being affected by common mode noise such as power supply fluctuation. In addition, by disposing the light detection element in the lubricant, the influence of the characteristic change due to the temperature change is canceled between the plurality of light detection elements, and highly accurate detection is possible.

In the present invention, the determination means may estimate the amount of contaminants mixed in the lubricant by comparing the signal intensities.
For example, when the lubricant is sealed in the bearing, foreign matter such as wear powder is mixed into the lubricant as the bearing is used. The detection output becomes small. Therefore, it is possible to estimate the amount of contaminants mixed in the lubricant from the value of the detection output of the determination means. On the other hand, since the increase in contaminants means the progress of the deterioration state of the lubricant, the determination means can detect the deterioration state of the lubricant from the estimated amount of contaminants.

  In the present invention, the light detection element may be composed of a detector and a light guide body whose base end is connected to the detector and whose front end is the light detection surface. Even in this configuration, since the positions of the light detection surfaces of the plurality of light detection elements are sequentially shifted from each other, the thickness of the lubricant itself, the intensity of the light source, and the distance from the light source to the light detection element In addition, the deterioration state of the lubricant can be detected without being affected by a temperature change or the like.

  In the present invention, the photodetecting element may comprise a detector and an optical fiber having a base end connected to the detector and having a tip serving as the photodetecting surface. When an optical fiber is used in this way, the detection unit in which a plurality of light detection elements are arranged can be made thin, so that the lubricant can be easily introduced into the detection unit, and stable detection can be performed. .

  In the present invention, the light source may be a line light source. As described above, when the light source is in the form of a line, the intensity of light incident on the detection unit becomes uniform regardless of the location, so that stable detection is possible.

  In this invention, the determination means may calculate the light transmittance of the lubricant. For example, if the deterioration of the lubricant progresses, such as the amount of contaminants mixed in the lubricant increases, the light transmittance of the lubricant is attenuated. Therefore, by calculating the light transmittance of the lubricant, A deterioration state can be detected.

In the present invention, the determination means includes a selection unit that excludes a light detection element whose output is saturated and a light detection element whose output intensity is less than a set value from the output signals of the plurality of light detection elements. In addition, the deterioration state of the lubricant may be detected using the output signals of the remaining light detection elements.
Depending on the intensity of the light emitted from the light source, the output may be saturated or almost no output may be obtained in some photodetectors. However, even in that case, it is possible to reliably detect the deterioration state of the lubricant from a wide range of locations by selecting the comparison output of the photodetecting element from which an appropriate output is obtained by the selection unit.

The bearing with a detecting device of the present invention is equipped with the lubricant deterioration detecting device having any one of the above configurations of the present invention.
According to this configuration, it is possible to accurately detect deterioration of the lubricant enclosed in the bearing in real time or periodically. As a result, it is possible to determine the necessity of replacement of the lubricant before the operation abnormality occurs in the bearing, and it is possible to prevent the bearing from being damaged due to poor lubrication. In addition, since the necessity for replacing the lubricant can be determined by the output of the lubricant deterioration detecting device, the amount of lubricant discarded before the expiration date is reduced.

The lubricant deterioration detection device of the present invention includes a light source and a plurality of light detection elements that detect transmitted light emitted from the light source and transmitted through the lubricant, and the plurality of light detection elements are provided on a light detection surface. Since the position is sequentially shifted from each other, and there is provided a determination means for detecting the deterioration state of the lubricant by comparing the signal strengths of the outputs of the plurality of light detection elements, the degree of freedom of arrangement inside the bearing is high. The deterioration state of the lubricant can be detected stably without being affected by the thickness of the lubricant and the temperature change.
Since the bearing with the detecting device of the present invention is equipped with the lubricant deterioration detecting device of the above invention, it is possible to accurately detect the deterioration of the lubricant enclosed in the bearing in real time or periodically. it can. As a result, it is possible to determine the necessity of replacement of the lubricant before the operation abnormality occurs in the bearing, and it is possible to prevent the bearing from being damaged due to poor lubrication. In addition, since the necessity for replacing the lubricant can be determined by the output of the lubricant deterioration detecting device, the amount of lubricant discarded before the expiration date is reduced.

  A first embodiment of the present invention will be described with reference to FIGS. FIG. 1A shows a schematic configuration diagram of the lubricant deterioration detection device of this embodiment. The lubricant deterioration detection apparatus 1 includes a light source 2, a plurality of light detection elements 3 that detect light transmitted from the light source 2 and transmitted through the lubricant 5 to be detected, and the plurality of light detection elements 3. And determining means 4 for detecting the deterioration state of the lubricant 5 by comparing the signal strengths of the outputs. The lubricant 5 to be detected is, for example, a lubricant sealed inside the bearing. The plurality of light detecting elements 3 are arranged in a line, and the positions of the light detecting surfaces are sequentially shifted from each other by a predetermined distance d with respect to the light traveling direction. Further, each photodetecting element 3 is disposed in the lubricant 5.

  In this embodiment, each of the light detection elements 3 includes a detector 13A and a light guide body 13B having a base end connected to the detector 13A and a tip serving as the light detection surface. Each detector 13A is configured as an array arranged in the same position with respect to the traveling direction of light. On the other hand, the lengths of the light guides 13B are different from each other so that the positions of the tips are sequentially shifted from each other by a predetermined distance d with respect to the light traveling direction. Thus, the positions of the light detection surfaces of the plurality of light detection elements 3 are sequentially shifted from each other by a predetermined distance d with respect to the light traveling direction. As the detector 13A, a photodiode, phototransistor, CDS, solar cell, photomultiplier tube, or the like is used. The light guide 13B is made of, for example, a cylindrical synthetic resin or a transparent material such as glass, the tip serving as the light detection surface is a transparent circular window, and a reflective material is applied to the outer peripheral surface. The incident light reaches the detector 13A.

  An optical fiber may be used as the light guide 13B. When an optical fiber is used, the detection part in which the plurality of light detection elements 3 are arranged can be made thin, so that the lubricant 5 can easily enter the detection part, and stable detection is possible.

  Further, it is desirable that the light source 2 is also a line light source with respect to the light detection elements 3 arranged in a line. As described above, when the light source 2 has a line shape corresponding to the arrangement of the light detection elements 3, the intensity of the light incident on the detection unit is uniform regardless of the place, so that stable detection is possible. As the light source 2, an LED, an incandescent bulb, a semiconductor laser diode, an EL, an organic EL, a fluorescent tube, or the like can be used.

The determination means 4 includes a determination unit 14 and a selection unit 15 as shown in FIG. The determination unit 14 is a circuit unit configured by, for example, a plurality of differential amplifiers 16 that respectively compare the signal strengths of the outputs of a pair of two adjacent photodetectors 3 that are shifted by the distance d among the photodetectors 3. It is. The selection unit 15 excludes those in which the output of the light detection element 3 is saturated depending on the intensity of light and those in which almost no output is obtained, and outputs the set of adjacent light detection elements 3 that can obtain an appropriate output. It is a circuit unit for selecting a comparison result in the corresponding determination unit 14.
Depending on the intensity of the light emitted from the light source 2, the output may be saturated or almost no output may be obtained in some of the light detection elements 3. Even in that case, since the comparison output of the photodetecting element 3 from which an appropriate output is obtained is selected by the selection unit 15, the deterioration state of the lubricant 5 can be reliably detected.
Although FIG. 1B shows an example in which the determination unit 14 of the determination unit 4 is configured by a differential amplifier 16 that obtains the difference in signal intensity between the outputs of the adjacent photodetectors 3, this is not limitative. Instead, the circuit configuration may be such that the ratio of the signal intensity of the outputs of the adjacent photodetectors 3 is obtained.

In the lubricant deterioration detecting device 1 having the above-described configuration, the intensity of light transmitted through the lubricant 5 is greatly attenuated depending on the distance transmitted. The relationship shown by the graph in FIG. 2 is present between the transmitted light intensity and the transmission distance. Assuming that the transmitted light intensity (transmitted light amount) is I, the transmission distance is x, and the incident light amount to the lubricant 5 is Iin, α is a constant,
I = Iinexp (−αx) (1)
It becomes.
Therefore, the signal intensities I0 and I1 of the outputs of the two adjacent photodetecting elements 3 whose photodetection surfaces are located at distances x0 and x1 are:
I0 = Iinexp (-αx0) (2)
I1 = Iinexp (-αx1) (3)
It becomes. Assuming that the determination means 4 obtains the ratio of the signal intensities of the outputs of two adjacent photodetectors 3 shifted by an interval d, the detection output of the determination means 4 is
(I1 / I0) = exp (-[alpha] (x1-x0))
= Exp (-αd) (4)
It becomes. That is, the detection output of the determination unit 4 is a value depending on the distance d between the light detection surfaces of the two adjacent light detection elements 3 regardless of the thickness of the lubricant 5 itself. Since this relationship holds between the respective photodetectors 3 arranged in an array, the detection output of the determination means 4 may be obtained using the output from any of the photodetectors 3.

  Further, the value of the constant α in the equation (4) varies depending on the state of the lubricant 5. For example, when the lubricant 5 is sealed in the bearing, foreign matter such as wear powder is mixed into the lubricant 5 as the bearing is used, so that the amount of the contaminant increases as the amount of the contaminant increases. The constant α increases. Therefore, when the determination means 4 obtains the ratio of the signal intensities of two adjacent photodetectors 3 shifted by the distance d as described above, the transmittance of the light transmitted through the optical path of the interval d in the lubricant 5 is determined. Thus, the amount of contaminants mixed in the lubricant 5 can be estimated from the value of the detected output. In addition, since the increase in the amount of contamination means the progress of the deterioration state of the lubricant 5, the determination unit 4 can detect the deterioration state of the lubricant 5 from the estimated amount of contamination.

  The determination means 4 may obtain a difference in signal intensity between the two light detection elements 3 shifted by the distance d. Also in this case, the determination means 4 detects the transmittance of light transmitted through the interval d in the lubricant 5, and therefore estimates the amount of contaminants mixed in the lubricant 5 from the detected output. The deterioration state of the lubricant 5 can be detected from the estimated amount of contaminants.

Thus, in this lubricant deterioration detection device 1, the plurality of light detection elements 3 are arranged so that the positions of their light detection surfaces are sequentially shifted from each other by the distance d with respect to the light traveling direction. Since the determination means 4 compares the output signal intensity of the two light detection elements 3 to detect the deterioration state of the lubricant 5, the thickness of the lubricant 5 itself, the intensity of the light source 2, the light source 2 The deterioration state of the lubricant 5 can be detected without being affected by the distance to the light detection element 3 or the like.
In addition, since the plurality of light detection elements 3 are arranged, even if some of the light detection elements 3 are saturated or almost no output can be obtained depending on the intensity of light, the determination means. 4, the selection unit 15 selects a comparison output of a pair of two adjacent photodetecting elements 3 from which a proper output is obtained from a plurality of detection results in the determination unit 14, and the lubricant 5 has a wide range. The deterioration state can be reliably detected from any place.

  As a result, even when the lubricant deterioration detection device 1 is installed inside the bearing or the like, the degree of freedom of arrangement becomes high, and a configuration that matches the restrictions on the installation space becomes possible. Further, since the deterioration state of the lubricant 5 is detected by comparing the signal intensities of the outputs of two adjacent photodetectors 3, it is possible to perform stable detection without being affected by common mode noise such as power supply fluctuation. Become. Further, since detection is performed in a state where the light detection element 3 is disposed in the lubricant 5, the influence of the characteristic change due to the temperature change is canceled between the two adjacent light detection elements 3, and the detection is performed with high accuracy. Is possible.

  In the above configuration, a temperature sensor is arranged in the vicinity of the arrangement portion of the photodetecting element 3 and the temperature of the lubricant 5 and the photodetecting element 3 is observed, so that the detection result is corrected according to the temperature change. Anyway. Specifically, for example, a change in the detection signal due to a temperature change may be measured in advance, and a circuit for correcting the detection signal at the actual use temperature may be provided separately. In this case, if the temperature of the lubricant 6 is known, it is possible to avoid mistaking the change in the detection signal due to the change in the environmental temperature as being caused by the deterioration of the lubricant 5. Thereby, more accurate detection becomes possible.

  In the above configuration, the determination unit 4 may include a comparison circuit that compares a detection signal obtained by comparing the signal strengths of the outputs of the two adjacent photodetectors 3 with a predetermined reference value. In this case, since it can be easily determined that the deterioration state of the lubricant 5 is equal to or higher than a predetermined level, it can be used as a guideline for the replacement time of the lubricant 5.

FIG. 3 shows a specific configuration example of the lubricant deterioration detection device 1 of FIG. In this example, in a planar housing 17 having a groove portion 18, a plurality of light detection elements 3 are arranged in a planar shape on one side wall of the groove portion 18, and the light source 2 is disposed on the other side wall of the groove portion 18. The lubricant 5 entering 18 is detected.
When configured in this manner, it is possible to detect the deterioration state of the lubricant 5 entering the groove 18 and distributed in a planar shape.

  In the embodiment shown in FIGS. 1 to 4, the case where the light detection element 3 includes the detector 13A and the light guide 13B is shown, but the light guide 13B is omitted as shown in FIG. Alternatively, the light detection element 3 may be configured only by the detectors, and the detectors may be arranged so that the positions of the light detection surfaces are sequentially shifted from each other by a predetermined distance d.

FIG. 5 is a cross-sectional view in which a bearing with a detection device on which the lubricant deterioration detection device 1 described above is mounted is used in a railway vehicle bearing unit. The railcar bearing unit in this case includes a bearing 21 with a detection device and an oil drain 22 and a rear lid 23 which are accessory parts provided on both sides of the inner ring 24 respectively. The bearing 21 is a roller bearing, more specifically, a double row tapered roller bearing. The split type inner rings 24 and 24 provided for the rollers 26 and 26 in each row, the integral type outer ring 25, the rollers 26 and 26, respectively. 26 and a retainer 27.
The rear lid 23 is attached to the axle 30 on the center side with respect to the bearing 21 and is in sliding contact with the outer peripheral oil seal 28. The oil drain 22 is attached to the axle 30 and has an oil seal 29 in sliding contact with the outer periphery. A lubricant is sealed inside the bearing 21 by the oil seals 28 and 29 disposed at both ends of the bearing 21, and dust and water resistance are ensured.

The lubricant deterioration detection device 1 is mounted between the raceway surfaces of both rows on the inner diameter surface of the outer ring 25 of the bearing 21 and detects deterioration of the lubricant sealed in the bearing. The lubricant deterioration detection device 1 is disposed near the end face of the roller 26. The outer ring 25 is provided with a cable insertion hole 25a through which the wiring cable 19 of the lubricant deterioration detecting device 1 is inserted, and the insertion portion of the wiring cable 19 is subjected to waterproofing / oilproofing treatment. Through the wiring cable 19, power is supplied from the outside of the bearing to the lubricant deterioration detecting device 1 and a detection signal is taken out of the bearing. This prevents moisture, dust and the like from entering the bearing from the mounting portion of the lubricant deterioration detection device 1.
In this bearing 21 with a detecting device equipped with the lubricant deterioration detecting device 1, the deterioration of the lubricant enclosed in the bearing can be accurately detected in real time or periodically. As a result, it is possible to determine the necessity for replacement of the lubricant before the operation abnormality occurs in the bearing 21, and to prevent damage to the bearing 21 due to poor lubrication. Further, since the necessity of replacing the lubricant can be determined by the output of the lubricant deterioration detecting device 1, the amount of lubricant discarded before the expiration date is reduced.

  FIG. 6 shows another example of a bearing with a detection device. This bearing with detection device 21 </ b> A is obtained by mounting the above-described lubricant deterioration detection device 1 on the inner surface of the oil seal 29 in the bearing with detection device 21 shown in FIG. 5. In this case, the lubricant deterioration detection device 1 is disposed near the end face of the cage 27.

  FIG. 7 shows still another example of the bearing with the detection device. This bearing 21B with a detecting device is the same as the bearing 21 with a detecting device shown in FIG. 5 except that the above-described lubricant deterioration detecting device 1 is attached to the side of the rolling surface of the outer ring 25. As described above, by disposing the lubricant deterioration detection device 1 on the side of the rolling surface, it is possible to reliably detect the state of the lubricant that contributes to lubrication.

(A) is a schematic block diagram of the lubricant deterioration detection apparatus concerning 1st Embodiment of this invention, (B) is a block diagram of the determination means in the same lubricant deterioration detection apparatus. It is a graph which shows the relationship between the transmission distance of the light which permeate | transmits a lubricant, and the intensity | strength of transmitted light. It is a perspective view which shows the specific structural example of the said lubricant deterioration detection apparatus. It is a schematic block diagram which shows a part of lubricant deterioration detection apparatus concerning other embodiment of this invention. It is sectional drawing of an example of the bearing with a lubricant deterioration detection apparatus carrying the said lubricant deterioration detection apparatus. It is sectional drawing of the other example of the bearing with a lubricant deterioration detection apparatus carrying the said lubricant deterioration detection apparatus. It is sectional drawing of the further another example of the bearing with a lubricant deterioration detection apparatus carrying the said lubricant deterioration detection apparatus. It is a schematic block diagram of the proposal example of a lubricant deterioration detection apparatus. It is a schematic block diagram of the other proposal example of a lubricant deterioration detection apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Lubricant deterioration detection apparatus 2 ... Light source 3 ... Photodetection element 4 ... Determination means 5 ... Lubricant 13A ... Detector 13B ... Light guide 21, 21, A, 21B ... Bearing with lubricant deterioration detection apparatus

Claims (8)

  A light source, and a plurality of light detection elements that detect light transmitted from the light source and transmitted through the lubricant, wherein the plurality of light detection elements are sequentially shifted in position from each other, A lubricant deterioration detection device provided with a determination unit that detects a deterioration state of a lubricant by comparing signal intensities of outputs of a plurality of light detection elements.   2. The lubricant deterioration detection apparatus according to claim 1, wherein the determination unit estimates the amount of contaminants mixed in the lubricant by comparing the signal intensities.   3. The lubricant deterioration detecting device according to claim 1, wherein the photodetecting element includes a detector and a light guide body having a base end connected to the detector and having a tip serving as the photodetecting surface. .   3. The lubricant deterioration detecting device according to claim 1, wherein the photodetecting element includes a detector and an optical fiber having a base end connected to the detector and having a tip serving as the photodetecting surface.   5. The lubricant deterioration detection device according to claim 1, wherein the light source is a line light source.   6. The lubricant deterioration detection device according to claim 1, wherein the determination unit calculates a light transmittance of the lubricant.   7. The detection unit according to claim 1, wherein the determination unit includes a light detection element whose output is saturated from output signals of a plurality of light detection elements, and a light detection element whose light detection intensity is less than a set value. The lubricant deterioration detecting device has a selection unit that excludes the output signal of the above and detects the deterioration state of the lubricant using the output signals of the remaining light detection elements.   A bearing with a detection device, wherein the lubricant deterioration detection device according to any one of claims 1 to 7 is mounted on the bearing.

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