JP2008139185A - Lubricant degradation detector of bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lubricant degradation detector of a bearing that can stably and accurately detect a lubricant degradation state inside a bearing. <P>SOLUTION: The lubricant degradation detector has an optical fiber 4 extending in a circular arc shape along the bearing space between the inner ring and outer ring of a rolling bearing. A light emitting element and a light receiving element are arranged on both ends of the optical fiber 4, respectively. A gap 5 for measurement is arranged in the intermediate part of the optical fiber 4, and arranged in the bearing space. The both-side opposite surfaces 4a forming the gap 5 for measurement of the optical fiber 4 are tilted from the inner ring side toward the outer ring side or from the outer ring side toward the inner ring side, respectively, and are positioned on the same axis. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a lubricant deterioration detection device for a bearing that detects a deterioration state due to a contaminant of a lubricant enclosed in a rolling bearing.

  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 bearings, etc., will be dealt with after an operational abnormality occurs due to the end of its 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.
Sensors such as electrodes and coils are placed inside the bearing seal to detect the wear state of the bearing, and the electrical characteristics of the lubricant mixed with wear powder are measured by resistance value, capacitance, magnetic resistance, and impedance. There has been proposed a sensor-equipped bearing that is detected as such a change (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 split ring-shaped optical fiber 44 is provided at both ends so that the light-emitting element 42 and the light-receiving element 43 face each other. An optical configuration was considered in which a measurement gap 47 with a lubricant 45 interposed in a part in the circumferential direction was provided.
In the configuration of FIG. 8, the light emitted from the light emitting element 42 passes through the lubricant 45 existing in the measurement gap 47 via the optical fiber 44 and is further detected by the light receiving element 43 via the optical fiber 44. The amount of foreign matter such as iron powder mixed in the lubricant 45 is estimated from the amount of transmitted light detected by the light receiving element 43.

  However, when such an optical sensor is incorporated in a bearing and used for detecting the deterioration of the lubricant enclosed in the bearing, the optical fiber 44 is not protected, and therefore the optical fiber 44 is not capable of flowing the lubricant. Under load. For this reason, the output may fluctuate due to movement of the optical fiber 44 or the optical fiber 44 may be damaged, and stable and accurate detection cannot be performed.

As a measure for preventing the optical fiber 44 from moving due to the flow of the lubricant, it is conceivable to provide a cover that covers a portion of the optical fiber 44 other than the vicinity of the measurement gap 47.
However, in this case, since the cover restricts the movement of the lubricant in the bearing together with the cage as the rolling element rotates, the lubricant may not easily enter the measurement gap 47. Further, since the lubricant moves in the circumferential direction of the bearing, if the facing surface of the optical fiber 44 facing the measurement gap 47 is set so that the measurement gap 47 opens in the radial direction of the bearing, the measurement is performed. Since the entry of the lubricant into the gap 47 for use is further hindered, a stable and accurate detection cannot be performed.

  An object of the present invention is to provide a lubricant deterioration detection device for a bearing that can stably and accurately detect a lubricant deterioration state inside the bearing.

In the lubricant deterioration detecting device of the present invention, an optical fiber extending in an arc shape is provided along a bearing space between inner and outer rings of a rolling bearing, and a light emitting element and a light receiving element are respectively disposed at both ends of the optical fiber. A measurement gap is provided in the middle of the optical fiber, the measurement gap is disposed in the bearing space, and the opposing surfaces on both sides forming the measurement gap of the optical fiber are respectively changed from the inner ring side to the outer ring side or the outer ring side. It is characterized in that it is provided so as to be inclined toward the inner ring side and located coaxially with each other.
According to this configuration, the facing surface of the optical fiber constituting the measurement gap is inclined from the inner ring side to the outer ring side or from the outer ring side to the inner ring side, and the inclination angle with respect to the tangent to the pitch circle of the bearing is set. Therefore, the lubricant that moves in the circumferential direction in the bearing along with the rotation of the rolling elements easily enters the measurement gap. As a result, the deterioration state of the lubricant inside the bearing can be detected stably and accurately.

  In this invention, you may arrange | position the said measurement gap of the said optical fiber to an internal diameter side rather than the cyclic | annular holder | retainer which hold | maintains the rolling element in the said rolling bearing.

In this invention, a fixture for fixing the optical fiber to the outer ring is provided, and the lubricant in the bearing space is positioned in the vicinity of the gap forming end portion that forms the measurement gap of the optical fiber. In addition, a resistor that resists rotational movement may be provided in the fixture.
When the resistor is provided in this way, the lubricant that moves in the vicinity of the measurement gap can be stored in the vicinity of the resistor. As a result, the lubricant stored in the vicinity of the resistor pushes out the lubricant that was previously present in the measurement gap, and instead enters the measurement gap instead of being inserted in sequence. The acting lubricant is targeted for detection, and the deterioration of the lubricant can be detected more stably and accurately.

  The bearing lubricant deterioration detecting device according to the present invention includes an optical fiber extending in an arc shape along the bearing space between the inner and outer rings of the rolling bearing, and the light emitting element and the light receiving element are respectively disposed at both ends of the optical fiber. A measurement gap is provided in the middle of the optical fiber, the measurement gap is arranged in the bearing space, and the opposing surfaces on both sides forming the measurement gap of the optical fiber are respectively changed from the inner ring side to the outer ring side, or Since they are provided so as to be inclined from the outer ring side toward the inner ring side and coaxially with each other, the deterioration state of the lubricant in the bearing can be detected stably and accurately.

An embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows an example of a rolling bearing incorporating the lubricant deterioration detection device of this embodiment. The rolling bearing 20 is a railway vehicle bearing, and an oil drain 25 and a rear lid 26 which are accessories provided in contact with both sides of the inner ring 21 constitute a railway vehicle bearing unit. The rolling bearing 20 is composed of a roller bearing, specifically, a double row tapered roller bearing, and includes divided inner rings 21 and 21 provided for the rollers 23 and 23 in each row, an integral outer ring 22, and the rollers 23. , 23 and a cage 24.
The oil drain 25 is attached to the axle 40 and has an oil seal 31 in sliding contact with the outer periphery. The oil seal 31 is press-fitted to an inner diameter surface of an annular seal case 27 attached to one end portion corresponding to the oil drain 25 of the outer ring 22 via a ring member 29 having an L-shaped cross section. The lubricant deterioration detection device 1 is concentrically attached to the inside of the seal case 27.
The rear lid 26 is attached to the axle 40 on the center side of the bearing 20 and has an oil seal 32 in sliding contact with the outer periphery. The oil seal 32 is press-fitted into an inner diameter surface of an annular seal case 28 attached to the other end portion of the outer ring 22 corresponding to the rear lid 26 via a ring member 30 having an L-shaped cross section. A lubricant is sealed inside the bearing 20 by the oil seals 31 and 32 disposed at both ends of the bearing 20, and dust and water resistance are ensured.

The lubricant deterioration detection device 1 detects deterioration of the lubricant incorporated in the bearing 20 and enclosed in the bearing. As shown in a schematic configuration diagram of FIG. 2, the light emitting element 2 and the light receiving element 3 And an arcuate optical fiber 4 and a determination means 6 for determining deterioration of the lubricant based on the output of the light receiving element 3. One end of the optical fiber 4 is disposed to face the light emitting surface of the light emitting element 2, and the other end is disposed to face the light receiving surface of the light receiving element 3. Further, a measurement gap 7 with a lubricant 5 interposed is provided in a part of the optical fiber 4 in the circumferential direction.
In this way, by providing the measurement gap 7 with the lubricant 5 to be detected interposed in a part of the circular optical fiber 4 in the circumferential direction, the light emitted from the light emitting element 2 passes through the optical fiber 4. Then, the lubricant 5 is transmitted, and the transmitted light is further incident on the light receiving element 3 through the optical fiber 4.

  As the light emitting element 2, an LED, an EL, an organic EL, or the like can be used and driven by the light emitting circuit 8. As the light receiving element 3, a photodiode, a phototransistor, or the like can be used, and the amount of light received by the light receiving element 3 is detected by the light receiving circuit 9 that receives the output.

  The optical fiber 4 is provided on the outer ring 22 side of the rolling bearing 20 via fixtures 10 to 13. One fixture 12 is an arc-shaped member that also serves as a cover that covers a portion of the optical fiber 4 except for the vicinity of the measurement gap 7 and protects the optical fiber 4 from the load caused by the flow of the lubricant 5 to be detected. As shown in FIG. 3B showing a cross-sectional view taken along the line BB in FIG. 2, the cross-sectional outline is made of a rigid material having an S-shape, for example, a synthetic resin or a metal material. Specifically, the cover-fixing fixture 12 covers at least one side (right side in FIG. 3B) of the arc-shaped optical fiber 4 in the arc central axis direction. When the lubricant deterioration detection device 1 is installed in the bearing, the surface side (the right side surface in FIG. 3B) of the fixture 12 is disposed so as to be exposed to the lubricant sealed in the bearing.

  The other fixture 10 for fixing the optical fiber 4 is an arc-shaped member joined to the lower half of the back surface (left side surface in FIG. 3B) of the fixture 12 also serving as a cover. Both ends of the optical fiber 4 are fixed to the fixture 10, and the light emitting element 2 and the light receiving element 3 are also fixed to the fixture 10. Further, as shown in FIG. 3B, other than the vicinity of the measurement gap 7 of the optical fiber 4 in the arc-shaped space 16 formed by being sandwiched between the front surface side fixing tool 12 and the back surface side fixing tool 10. Part is placed. Thereby, the optical fiber 4, the light emitting element 2, and the light receiving element 3 are protected from the load by the flow of the lubricant 5. Still another fixing tool 11 for fixing the optical fiber 4 is fixed to the front side of the fixing tool 10 as shown in FIG. 3A showing a cross-sectional view taken along the line AA of FIG. The vicinity of the measurement gap 7 of the optical fiber 4 is fixed to the tool 11 and positioned.

  A slit-like opening 14 extending in the circumferential direction is provided in the middle in the circumferential direction of the fixing tool 12 serving as a cover at a position corresponding to the measurement gap 7 of the optical fiber 4 as shown in a front view of FIG. As a result, the measurement gap 7 is exposed to the lubricant 5 inside the bearing. As shown in a plan view in FIG. 4, the fixture 11 has a portion that supports the vicinity of the measurement gap 7 of the optical fiber 4 from the opening 14 of the fixture 12 serving as a cover toward the surface of the fixture 12. The projecting portion 11a projects in a bifurcated shape. Accordingly, the vicinity of the measurement gap 7 of the optical fiber 4 is projected outward from the fixing tool 12 serving also as a cover.

  As shown in FIGS. 5 (A) and 5 (B) which are enlarged plan views and front views of the vicinity of the measurement gap 7 of the optical fiber 4, the other fixture 13 is made of a pipe, and the optical fiber. 4 other than the vicinity of the measuring gap 7 is inserted into the pipe-shaped fixture 13 with almost no gap. The fixture 13 prevents the optical fiber 4 from being deformed.

  As shown in FIG. 1, when attaching the lubricant deterioration detecting device 1 to the bearing 20, the cover fixing fixture 12 of the lubricant deterioration detecting device 1 is fitted into the inner diameter surface of the large diameter step portion of the seal case 27. The lubricant deterioration detection device 1 is pressed against the large-diameter stepped end surface of the seal case 27 and the upright plate portion of the ring member 29 (FIG. 3B) by the press-fitting ring 34 that is press-fitted. Thereby, the lubricant deterioration detecting device 1 is positioned and fixed in the axial direction, and the optical fiber 4 extending in the circumferential direction is arranged in the bearing space between the inner and outer rings 21 and 22 of the rolling bearing 20.

  As shown in FIG. 6 which shows the relationship between the vicinity of the measurement gap 7 of the optical fiber 4 and the bearing inner ring 21 in a front view, both opposing surfaces 4a of the optical fiber 4 forming the measurement gap 7 are Is inclined with respect to the tangential direction A of the inner ring 21 at the circumferential position. That is, it is tilted from the inner ring 21 side toward the outer ring 22 side or from the outer ring 22 side toward the inner ring 21 side. In this case, the opposing surfaces 4 a of the optical fibers 4 are coaxially positioned to each other and are substantially perpendicular to the axial direction P of the optical fiber 4, but a gap that forms the measurement gap 7 of the optical fiber 4. By setting the forming end 4b to have an inclination angle β (90 ° −α) with respect to the tangential direction A of the inner ring 21, the opposed surface 4a has an inclination angle α with respect to the tangential direction A of the inner ring 21. It is

  When the lubricant 5 is new, it is nearly transparent, and the intensity of transmitted light that is projected from the light emitting element 2 via the optical fiber 4 and transmitted through the lubricant 5 is high. However, as the amount of foreign matter such as iron powder (wear powder) mixed in the lubricant 5 increases, the intensity of transmitted light gradually decreases. Therefore, the determination unit 6 detects the amount of foreign matter mixed in the lubricant 5 from the output of the light receiving element 3 corresponding to the intensity of transmitted light. Since the increase in the amount of foreign matter mixed in the lubricant 5 means the progress of deterioration of the lubricant 5, the degree of deterioration of the lubricant 5 can be estimated from the detected amount of foreign matter.

  Thus, in this bearing lubricant deterioration detection device 1, the optical fiber 4 extending in the circumferential direction is provided in the bearing space between the inner and outer rings 21, 22 of the rolling bearing 20, and light emitting elements are provided at both ends of the optical fiber 4. 2 and the light receiving element 3 are provided, a measurement gap 7 is provided in the middle of the optical fiber 4, and a circumferential position of the measurement gap 7 is formed on the opposing surface 4 a of the optical fiber 4 constituting the measurement gap 7. Is inclined with respect to the tangential direction A (FIG. 6) of the inner ring 21, the opening direction of the measurement gap 7 does not become the radial direction of the bearing 20, and the cage 23 rotates with the rotation of the roller 23. The lubricant that moves in the circumferential direction in the bearing together with 24 easily enters the measurement gap 7. As a result, the deterioration state of the lubricant inside the bearing can be detected stably and accurately.

By making the opposing surface 4a of the optical fiber 4 inclined with respect to the axis, the opposing surface 4a can be given an inclination angle α with respect to the tangential direction A of the inner ring 21, but in this case Setting the measurement gap 7 becomes difficult.
In this embodiment, as shown in FIG. 6, the facing surface 4 a that forms the measurement gap 7 of the optical fiber 4 is substantially perpendicular to the axial direction P of the optical fiber 4, and the measurement gap 7 of the optical fiber 4. Is formed with an inclination angle β with respect to the tangential direction A of the inner ring 21, so that an optical fiber is formed with respect to the tangential direction A of the inner ring 21 at the circumferential position of the measurement gap 7. Since the four opposing surfaces 4a have the inclination angle α, the work of setting the gap amount of the measurement gap 7 to a constant amount is facilitated.

Further, in this embodiment, since the portion other than the vicinity of the measurement gap 7 in the optical fiber 4 is covered with the fixing tool 12 that also serves as a cover, the optical fiber 4 is protected from the load caused by the flow of the lubricant 5. It is possible to protect the optical fiber 4 from being damaged.
Furthermore, in this embodiment, the vicinity of the gap 7 for measurement of the optical fiber 4 is supported by supporting the vicinity of the gap forming end 4 b that forms the measurement gap 7 of the optical fiber 4 with the protrusion 11 a of the fixture 11. Since the portion protrudes from the cover-fixing fixture 12, the cover-fixing fixture 12 does not hinder the movement of the lubricant 5 in the vicinity of the measurement gap 7. With these configurations, the lubricant deterioration state inside the bearing can be detected more stably and accurately.

  FIG. 7 is a front view of the relationship with the bearing inner ring 21 in another configuration example in the vicinity of the measurement gap 7 of the optical fiber 4 in the lubricant deterioration detection device 1. In this configuration example, a resistance that is positioned in the vicinity of the gap forming end 4 b that forms the measurement gap 7 of the optical fiber 4 and serves as a resistance against the rotational movement of the lubricant 5 in the bearing space together with the inner ring 21. The body 17 is located. Specifically, the resistor 17 is provided in the vicinity of the measurement gap 7 in the fixture 13 made of a pipe through which the optical fiber 4 is inserted, and has a cylindrical shape surrounding the optical fiber 4. Opposing surfaces 17 a of the resistor 17 on both sides are parallel to each other and inclined with respect to the optical fiber 4. The inclination direction of the opposing surface 17a of the resistor 17 is a direction in which the inclination of the opposing surface 4a of the optical fiber 4 is further strengthened. Other configurations are the same as those in the case of FIGS.

  When the resistor 17 is provided in this way, the lubricant 5 moving in the vicinity of the measurement gap 7 can be stored in the vicinity of the resistor 17. As a result, the lubricant 5 accumulated in the vicinity of the resistor 17 pushes out the lubricant 5 that has been present in the measurement gap 7 so far and instead enters the measurement gap 7 instead of being replaced. Therefore, the lubricant 5 that always acts on the lubrication is to be detected, and the deterioration of the lubricant 5 can be detected more stably and accurately.

It is sectional drawing of the bearing carrying the lubricant deterioration detection apparatus which concerns on one Embodiment of this invention. It is a schematic block diagram of the same lubricant deterioration detection apparatus. 2A is a cross-sectional view taken along the line AA in FIG. 2, FIG. 2B is a cross-sectional view taken along the line BB in FIG. 2, and FIG. 3C is a side view seen from the direction of the arrow C in FIG. It is a partial top view of a lubricant deterioration detection apparatus. (A) is the top view which expanded a part of FIG. 4, (B) is the same front view. It is a front view which shows the relationship between the gap part for a measurement of an optical fiber, and a bearing inner ring | wheel. It is a front view which shows the relationship with the bearing inner ring | wheel of the other structural example of the measurement gap vicinity part of an optical fiber. 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 emitting element 3 ... Light receiving element 4 ... Optical fiber 4a ... Opposite surface 4b ... Gap formation edge part 5 ... Lubricant 7 ... Measuring gap 10-13 ... Fixing tool 17 ... Resistor 20 ... Rolling bearing 21 ... inner ring 22 ... outer ring

Claims (3)

  An optical fiber extending in an arc shape is provided along the bearing space between the inner and outer rings of the rolling bearing, a light emitting element and a light receiving element are arranged at both ends of the optical fiber, and a measurement gap is provided in the middle of the optical fiber. A measurement gap is disposed in the bearing space, and the opposing surfaces on both sides forming the measurement gap of the optical fiber are inclined so as to go from the inner ring side to the outer ring side or from the outer ring side to the inner ring side, respectively. And a lubricant deterioration detecting device for a bearing, characterized by being provided coaxially with each other.   2. The lubricant deterioration detection device for a bearing according to claim 1, wherein the measurement gap of the optical fiber is arranged on an inner diameter side of an annular cage that holds a rolling element in the rolling bearing.   3. The fixing device according to claim 1, further comprising: a fixture that fixes the optical fiber to an outer ring, wherein the optical fiber is positioned in the vicinity of a gap forming end portion that forms the measurement gap of the optical fiber. A lubricant deterioration detecting device for a bearing, in which a resistor is provided on the fixture to be a resistance against rotational movement of the lubricant together with the inner ring.

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