JP2007248211A - Lubricant deterioration detection device, and bearing with detection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical type lubricant deterioration detection device capable of detecting deterioration of a lubricant even in the case where the lubricant is thick or where transparency is poor, and a bearing with the detection device equipped with the lubricant deterioration detection device. <P>SOLUTION: This lubricant deterioration detection device 1 is equipped with a light emitting part 2 and a light receiving part 3 interposing the lubricant 5 which is a detection object between them, and a determination means 4. The determination means 4 emits a periodical light emission command to the light emitting part 2, takes an output from the light receiving part 3 synchronously with light emission, determines a light transmittance of the lubricant 5, and thereby detects the amount of a foreign matter intermingled in the lubricant 5. <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 lubricant deterioration 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. 9, a lubricant 35 to be detected is interposed between the light emitting unit 32 and the light receiving unit 33, and is emitted from the light emitting unit 32 and passes through the lubricant 35. A configuration was considered in which the light transmittance is obtained by measuring light with the light receiving unit 33 and the amount of impurities mixed in the lubricant 35 is estimated therefrom.

However, in an actual device such as a bearing having the lubricant 35 to be detected, the lubricant 35 may be thick or the light transmittance of the lubricant 35 may be small. Even when the deterioration of the lubricant 35 is detected, the amount of light received by the light receiving unit 33 may be small and cannot be measured. In such a case, it is necessary to use a light emitting unit 32 having a large amount of light such as a laser diode or an incandescent bulb in consideration of the influence of noise or the like. However, laser diodes, incandescent bulbs, etc. are expensive and have shortcomings of short lifetime.
Therefore, for example, an inexpensive LED is used as the light emitting unit 32, but the LED generally has a small amount of light. In this case, when the thickness of the lubricant 35 is large or when the light transmittance of the lubricant 35 is small, the amount of light received by the light receiving unit 33 is small, and reliable measurement cannot be performed.

  An object of the present invention is to provide an optical lubricant deterioration detection device capable of detecting lubricant deterioration even when the lubricant is thick or when the transparency is poor, and a bearing with a detection device provided with the lubricant deterioration detection device. Is to provide.

According to a first aspect of the present invention, there is provided a lubricant deterioration detecting device, wherein a light emitting unit and a light receiving unit that interpose a lubricant to be detected between them, a light emission command to the light emitting unit periodically, and a light receiving unit And a determination means for detecting the amount of foreign matter mixed in the lubricant by obtaining the output of the portion in synchronism with light emission and determining the light transmittance of the lubricant.
According to this configuration, the light emitting unit having the lubricant to be detected interposed between the light receiving unit and the light emitting unit is periodically, that is, intermittently issued a light emission command, and the output of the light receiving unit is synchronized with the light emission. Therefore, even if an inexpensive LED, for example, is used as the light source of the light emitting unit, a large amount of light can be emitted without causing thermal destruction. Therefore, even when the lubricant is thick or the transparency is poor, a sufficient amount of received light can be obtained for measurement. As a result, the determination means can reliably detect the amount of foreign matter mixed in the lubricant by obtaining the light transmittance of the lubricant from the captured output of the light receiving unit.

According to a second aspect of the present invention, there is provided a lubricant deterioration detecting device, wherein a light emitting unit and a light receiving unit that interpose a lubricant to be detected between each other, a light emission command to the light emitting unit only during measurement, And a determination means for detecting the amount of foreign matter mixed in the lubricant by obtaining the output of the portion in synchronism with light emission and determining the light transmittance of the lubricant.
In this way, when a light emission command is issued from the determination means to the light emitting unit only at the timing required for measurement, even if an inexpensive LED is used as the light source of the light emitting unit, for example, the LED energization time is limited at the time of measurement A large amount of light can be emitted without causing thermal destruction, and the deterioration of the lubricant can be detected even when the lubricant is thick or the transparency is poor.

  In each of the above-described configurations of the present invention, error factor cancellation that cancels at least one of noise, dark current of the light receiving element, and circuit offset by comparing the light receiving signal during light emission with the light receiving signal during extinction Means may be provided. In this configuration, the error factor canceling means cancels noise, dark current of the light receiving element in the light receiving unit, circuit offset, etc. from the light output of the light receiving unit during light emission of the light emitting unit, so a highly accurate detection result is obtained. Obtainable.

In the case of each of the above configurations of the present invention, peak hold means for peak holding the output of the light receiving unit may be provided.
As described above, when the light amount output of the light receiving unit is peak-held by the peak hold unit, the light amount data can be freely taken in by the determination unit at any time thereafter.

In the case of each of the above-described configurations of the present invention, a second light-receiving unit that receives light emitted from the light-emitting unit without interposing a lubricant to be detected is provided, and the determination means is a lubricant to be detected. By comparing the signals of the first light receiving unit and the second light receiving unit, which are light receiving units interposing the agent, the light transmittance of the lubricant is obtained to detect the amount of foreign matter mixed in the lubricant. It may be good.
Thus, by comparing the light output of the first light receiving unit that receives light that has passed through the lubricant with the light output of the second light receiving unit that receives light that does not pass through the lubricant, light emission in the light emitting unit is achieved. Common mode noise such as uneven light emission of the element and power supply fluctuation can be canceled, and detection with higher accuracy becomes possible.

The bearing with a lubricant deterioration device according to the present invention is obtained by mounting the lubricant deterioration detection device having any one of the above-described configurations according to the present invention on a bearing.
According to this configuration, it is possible to accurately detect the deterioration of the lubricant enclosed in the bearing in real time. 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.

According to a first aspect of the present invention, there is provided a lubricant deterioration detecting device, wherein a light emitting unit and a light receiving unit that interpose a lubricant to be detected between them, a light emission command to the light emitting unit periodically, and a light receiving unit The output of the part is captured in synchronization with the light emission, and the light transmittance is obtained by determining the light transmittance of the lubricant and detecting the amount of foreign matter mixed in the lubricant. Therefore, the amount of light emitted from the light emitting portion can be increased, and the deterioration of the lubricant can be detected even when the lubricant is thick or the transparency is poor.
According to a second aspect of the present invention, there is provided a lubricant deterioration detecting device, wherein a light emitting unit and a light receiving unit that interpose a lubricant to be detected between each other, a light emission command to the light emitting unit only during measurement, The output of the part is captured in synchronization with the light emission, and the light transmittance is obtained by determining the light transmittance of the lubricant and detecting the amount of foreign matter mixed in the lubricant. Therefore, the amount of light emitted from the light emitting portion can be increased, and the deterioration of the lubricant can be detected even when the lubricant is thick or the transparency is poor.
Since the bearing with the lubricant deterioration detecting device of the present invention is equipped with the lubricant deterioration detecting device of the present invention, it is possible to accurately detect in real time the deterioration of the lubricant enclosed in the bearing. 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. 1 is a schematic configuration diagram of the lubricant deterioration detection device of this embodiment. The lubricant deterioration detection device 1 includes a light emitting unit 2 and a light receiving unit 3 that interpose a lubricant 5 to be detected between them, and a determination unit 4. The light emitting unit 2 has an LED (that is, a light emitting diode) 6 as a light source as shown in FIG. The LED 6 is connected in series with the current limiting resistor 7 and the transistor 8 which is a switching element between the power source and the ground. When the transistor 8 is turned on by the lighting command from the determination means 4, a current is supplied from the power source to the LED 6 through the current limiting resistor 7. Is supplied and the LED 6 emits light.

FIG. 3 is a circuit diagram for explaining the principle of the relationship between the amount of heat generated and the amount of light in the LED 6. When the current If flows from the power source through the current limiting resistor 7, the forward voltage of the LED 6 becomes Vf. Therefore, the loss P of the LED 6 in this case is
P = Vf × If (1)
This loss P becomes the amount of heat generated by the LED 6, and the LED 6 does not fail and can be used continuously unless it exceeds a predetermined allowable loss. Although the forward voltage Vf is a function of the current If, the forward voltage Vf hardly changes even if the current If changes greatly. Therefore, the loss P is approximately proportional to the current If. It is known that the amount of light emitted from the LED 6 is also substantially proportional to the current If.
Here, in order to increase the amount of light emitted from the LED 6, it is necessary to increase the current If. In this case, the loss P increases, and as a result, the allowable loss is exceeded and thermal destruction occurs. Therefore, in this lubricant deterioration detection device 1, the LED 6 is intermittently lit by the lighting control from the determination means 4 in order to avoid thermal destruction of the LED 6 and increase the amount of emitted light. When the lighting time is T and the lighting time is t, the loss P of the LED 6 when the lighting and lighting are alternately repeated is
P = Vf * If * T (T + t) (2)
It is.
Here, if the ratio of the lighting time t to the total time (T + t) is the duty ratio W,
W = T / (T + t) (3)
Than,
P = Vf × If × W (4)
It becomes.
Therefore, if the duty ratio W is reduced, the current If can be increased without increasing the average heat generation amount, that is, the loss P. Empirically, if the duty ratio W is reduced, the current If can be about 10 times that in continuous lighting, and the amount of light emitted from the LED 6 is also 10 times.

The determination unit 4 includes, for example, a built-in computer, and includes a light emission control unit 9 that performs the above-described periodic (intermittent) light emission command to the transistor 8 of the light emitting unit 2. A waveform diagram of the light emission command signal is shown in FIG. Further, the determination means 4 obtains the light transmittance of the lubricant 5 from the synchronous capturing unit 10 that captures the output of the light receiving unit 3 in synchronization with the light emission, and the light amount output of the captured light receiving unit 3 and mixes it in the lubricant 5. And a determination unit 12 that detects the amount of foreign matter. The output of the light receiving unit 3 is converted into a digital signal through the A / D converter 13 and is taken into the determination unit 4.
Further, the determination unit 4 also includes a cancel unit 11 that cancels noise, dark current of the LED 6, circuit offset, and the like from the light amount output of the light receiving unit 3 when the light emitting unit 2 emits light. The cancel unit 11 takes in the light amount output of the light receiving unit 3 when the light emitting unit 2 is turned off, and compares the value with the light amount output during light emission, so that the noise included in the light amount output during light emission and the dark current of the LED 6 It works as an error factor canceling means for canceling the offset of the circuit.

  Next, the operation of the lubricant deterioration detection device 1 will be described. When the measurement is necessary, the determination unit 4 sets the lighting command to the high level as in the section T in FIG. As a result, the transistor 8 in the light emitting section 2 in FIG. 2 is turned on, the current If flows through the LED 6 and the LED 6 emits light. Light emitted from the light emitting unit 2 passes through the lubricant 5 and is received by the light receiving unit 3. Since the current If flowing through the LED 6 is excessively slightly delayed from the lighting command, the light amount output at the light receiving portion 3 proportional to the current If is excessive at the rising portion as shown in the waveform diagram of FIG. In some cases, the amount of light may gradually decrease depending on the energization time. Therefore, in the synchronous capture unit 10 of the determination unit 4, when the light amount output of the light receiving unit 3 is captured through the A / D converter 13, capture is performed at a predetermined timing after a certain amount of stabilization time has elapsed from the lighting command. The timing is shown as a trigger in FIG. The determination unit 12 of the determination unit 4 obtains the light transmittance of the lubricant 5 from the light amount output of the light receiving unit 3 captured by the synchronous capturing unit 10 in synchronization with the light emission of the light emitting unit 2 and mixes in the lubricant 5. Detect the amount of foreign material. In addition, the cancel unit 11 of the determination unit 4 cancels noise, dark current of the LED 6, circuit offset, and the like from the light amount output of the light receiving unit 3 when the light emitting unit 2 emits light, so that a highly accurate detection result can be obtained. Can do.

  As described above, in the lubricant deterioration detection device 1, a light emission command is periodically (intermittently) issued from the determination unit 4 to the light emitting unit 2 that interposes the lubricant 5 to be detected between the light receiving unit 3. In addition, since the output of the light receiving unit 3 is taken into the determination unit 4 in synchronization with the light emission, even if an inexpensive LED 6 is used as the light source of the light emitting unit 2 as in the embodiment, thermal destruction does not occur. A large amount of light can be emitted, and a sufficient amount of received light can be obtained even when the lubricant 5 is thick or the transparency is poor. As a result, the determination unit 4 can reliably detect the amount of foreign matter mixed in the lubricant 5 by obtaining the light transmittance of the lubricant 5 from the captured output of the light receiving unit 3.

  In the above embodiment, the case where the lighting command is given to the light emitting unit 2 periodically (intermittently) is shown, but the light emission control unit 9 may issue the lighting command only at a timing required for measurement. In this case as well, even if an inexpensive LED 6 is used as the light source of the light emitting unit 2, the energization time of the LED 6 is limited at the time of measurement, so that a large amount of light can be emitted without causing thermal destruction. Even when the lubricant 5 is thick or the transparency is poor, the deterioration of the lubricant can be detected.

  FIG. 5 shows another embodiment of the present invention. The lubricant deterioration detection device 1 of this embodiment is obtained by adding a peak hold means 15 for peak-holding the light amount output of the light receiving unit 3 in the first embodiment shown in FIG. The output of the peak hold means 15 is converted into a digital signal through the A / D converter 16 and taken into the determination means 4. Here, the trigger of FIG. 4C, which is the timing at which the light output of the light receiving unit 3 is stabilized, is used as a timing signal for starting the peak hold means 15, but the peak hold means 15 may be started by a lighting command. . Further, the lighting command may be output periodically (intermittently) or only at a timing necessary for measurement.

  As described above, when the light output of the light receiving unit 3 is peak-held by the peak hold unit 15, the determination unit 4 can freely take in the light amount data at any time thereafter. In this embodiment, there is also a route for bypassing the peak hold means 15 and taking in the light amount output of the light receiving unit 3 into the determination means 4, so that the light amount output at the time of extinction is taken into the determination means 4 from this path. Thus, the noise, the dark current of the LED 6, the circuit offset, etc. can be canceled by comparing the value with the light output at the time of light emission.

  In the embodiment of FIG. 5, the lighting command to the light emitting unit 2 is performed using a dedicated oscillator or the like, and the output of the peak hold means 15 is input to a display such as a meter and the peak hold value is set by the display. The determination means 4 may be omitted by direct display. In this case, the deterioration state of the lubricant 5 to be detected is estimated by monitoring the peak hold value of the light amount output displayed on the display.

  FIG. 6 shows still another embodiment of the present invention. In the first embodiment shown in FIG. 1, the lubricant deterioration detection device 1 according to this embodiment includes a second light receiving unit 13 that receives light emitted from the light emitting unit 2 without the lubricant 5 to be detected. It is added. The light amount output of the light receiving unit 13 is converted into a digital signal through the A / D converter 17 and is taken into the determination means 4. In the determination unit 12 (FIG. 1) of the determination unit 4, the light output of the first light receiving unit 3 that receives light emitted from the light emitting unit 2 with the lubricant 4 to be detected interposed therebetween, and the second light receiving unit. The light transmittance of the lubricant 5 is obtained by comparing the light quantity output of 13, and the amount of foreign matter mixed in the lubricant 5 is detected.

  Thus, by comparing the light output of the first light receiving unit 3 that receives light transmitted through the lubricant 5 with the light output of the second light receiving unit 13 that receives light that does not transmit through the lubricant 5, Common mode noise such as uneven light emission of the light emitting element such as the LED 6 (FIG. 2) in the light emitting unit 2 or power supply fluctuation can be canceled, and detection with higher accuracy is possible.

FIG. 7 is a cross-sectional view in which a bearing with a detection device on which the above-described lubricant deterioration detection device 1 is mounted is used for a railway vehicle bearing unit. The railcar bearing unit in this case includes a bearing 21 with a lubricant deterioration detecting device and an oil drainer 22 and a rear lid 23 which are accessory parts provided in contact with 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 outer ring 25 of the bearing 21 is attached with a lubricant deterioration detection device 1 that detects the deterioration of the lubricant enclosed in the bearing. The lubricant deterioration detection device 1 is inserted into a detection device insertion hole 25a provided in the outer ring 25, and is fixed to the outer ring 25 with bolts or the like. The lubricant deterioration detection device 1 and its wiring cable 18 are subjected to waterproofing / oilproofing treatment. The mounting portion of the lubricant deterioration detection device 1 is also sealed with an oil resistant material. For example, the lubricant deterioration detection device 1 is inserted into the detection device insertion hole 25a of the outer ring 25 through the sealing seal 32, and an O-ring is used as the sealing seal 32, for example. As described above, the lubricant deterioration detecting device 1 is fixed to the outer ring 25 through the hermetic seal 32, so that moisture, dust and the like can be prevented from entering the bearing from the mounting portion of the lubricant deterioration detecting 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. Specifically, the state of the lubricant present in the vicinity of the lubricant deterioration detection device 1 can be detected, and the amount of iron powder mixed in the lubricant can be estimated. As a result, it is possible to determine the necessity of replacement of the lubricant before the operation abnormality occurs in the bearing 21, so that damage to the bearing 21 due to poor lubrication can be prevented. 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. 8 shows another example of the bearing with the lubricant deterioration detecting device. This bearing 21 A with a lubricant deterioration detecting device is the same as the bearing 21 with a lubricant deterioration detecting device 21 shown in FIG. 7 except that the lubricant deterioration detecting device 1 is attached in the vicinity of the inner surface of the seal 29. Other configurations are the same as the example of FIG.

1 is a schematic configuration diagram of a lubricant deterioration detection device according to a first embodiment of the present invention. It is a circuit diagram of the light emission part in the same lubricant deterioration detection apparatus. It is a circuit diagram for demonstrating the principle about the relationship between the emitted-heat amount and light quantity in LED of the light emission part. It is a wave form diagram of each part in a lubricant deterioration detector. It is a schematic block diagram of the lubricant deterioration detection apparatus which concerns on other embodiment of this invention. It is a schematic block diagram of the lubricant deterioration detection apparatus concerning further another embodiment of this invention. It is sectional drawing which shows an example of the bearing with a detection apparatus carrying the said lubricant deterioration detection apparatus. It is sectional drawing of the other example of the bearing with a detection apparatus which mounts the said lubricant deterioration detection apparatus. It is a schematic block diagram of the proposal example of a lubricant deterioration detection apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Lubricant deterioration detection apparatus 2 ... Light emission part 3 ... Light-receiving part 4 ... Determination part 5 ... Lubricant 11 ... Cancellation part (error factor cancellation means)
13 ... 2nd light-receiving part 15 ... Peak hold means 21, 21A ... Bearing with lubricant deterioration detector

Claims (6)

  A light emitting unit and a light receiving unit that interpose a lubricant to be detected, and a light emission command are periodically given to the light emitting unit, and the output of the light receiving unit is taken in synchronization with light emission, and the light of the lubricant A lubricant deterioration detection apparatus comprising: a determination unit that obtains transmittance and detects the amount of foreign matter mixed in the lubricant.   A light emitting part and a light receiving part that interpose a lubricant to be detected, and a light emission command to the light emitting part only at the time of measurement, and taking in the output of the light receiving part in synchronization with light emission, the light of the lubricant A lubricant deterioration detection apparatus comprising: a determination unit that obtains transmittance and detects the amount of foreign matter mixed in the lubricant.   3. The error factor canceling means according to claim 1, wherein the light receiving signal at the time of light emission is compared with the light receiving signal at the time of turning off to cancel at least one of noise, dark current of the light receiving element, and circuit offset. Lubricant deterioration detector provided with   4. The lubricant deterioration detection device according to claim 1, further comprising a peak hold unit that holds a peak of the output of the light receiving unit.   In any one of Claims 1 thru / or Claim 3, providing the 2nd light sensing part which receives the light emitted from the light emission part without interposing the lubricant used as a candidate for detection, and the above-mentioned judgment means is, Foreign matter mixed in the lubricant by determining the light transmittance of the lubricant by comparing the signals of the first light receiving portion and the second light receiving portion, which are light receiving portions interposing the lubricant to be detected. Lubricant deterioration detection device that detects the amount of oil. A bearing with a lubricant deterioration detecting device, wherein the lubricant deterioration detecting device according to any one of claims 1 to 5 is mounted on the bearing.

Images