JP2018159622A - Condition monitoring device and condition monitoring method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a condition monitoring device capable of highly accurately monitoring a displacement of a rotation shaft without influences of environments such as lubricant and water.SOLUTION: The present disclosure relates to a condition monitoring device for detecting abnormality of a bearing. The condition monitoring device comprises: a friction member 146 that is disposed in such a position facing a circumferential surface of a rotation shaft 20 that displacement of the rotation shaft 20 supported by the bearing causes a degree of contact with the rotation shaft to be varied; and a condition monitoring sensor 145 coming into contact with the friction member 146. The condition monitoring sensor 145 is an AE sensor or an acceleration sensor. The friction member 146 has such a shape that a contact area with the rotation shaft 20 increases in accordance with an increase in a displacement of the rotation shaft 20.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a state monitoring device and a state monitoring method for detecting a bearing abnormality.

  A state monitoring device that diagnoses abnormalities of rotating parts in an actual operating state in order to detect and maintain abnormalities of rotating parts such as railway vehicles and wind turbines for power generation at an early stage is known (Patent Document 1: Japanese Patent Laid-Open No. 2006-2006). -105956). With such a state monitoring device, it is possible to diagnose an abnormality from a remote location without having to manually disassemble and check the device incorporating the rotating component.

JP 2006-105956 A

  Bearing state monitoring devices often monitor the state by installing sensors that measure acceleration, speed, displacement, sound, and AE (Acoustic Emission) on fixed parts such as housings and cases.

  However, in the case of low speed rotation where the dn value (inner diameter × rotational speed) is 20000 or less, it is difficult to detect an abnormality with the conventional state monitoring device. For example, when detecting acceleration, speed, and sound, it is difficult to detect abnormality because the response is small. Further, when detecting AE, a signal from a part other than the damaged part, for example, a signal due to creep, contact between the cage and the raceway, contact between the rolling element and the cage, etc. is disturbed and it is difficult to detect the abnormality. Therefore, it is conceivable to use a displacement sensor, but even with a displacement sensor, the eddy current type has a large temperature drift, making it difficult to detect abnormalities with high accuracy. There is a problem in monitoring the condition of the bearing because of the great influence of the environment such as water.

  The present invention has been made to solve the above-described problems, and the object thereof is a state in which the displacement of the rotating shaft can be monitored with high accuracy without being affected by the environment such as lubricating oil and water. A monitoring device and a state monitoring method are provided.

  The present disclosure relates to a state monitoring device that detects an abnormality of a bearing in which a fixed ring is fixed to a housing. The state monitoring device includes a friction member disposed so as to face the peripheral surface of the rotation shaft so that the degree of contact changes when the rotation shaft supported by the bearing is displaced with respect to the housing, and the state monitoring contacting the friction member A sensor. The state monitoring sensor is an AE sensor or an acceleration sensor. The friction member has a shape such that the contact area with the rotation shaft increases as the displacement amount of the rotation shaft increases.

  Preferably, the contact area of the friction member with the rotating shaft increases stepwise as the displacement amount of the rotating shaft increases.

  Preferably, the friction member is arranged on a side where a bearing load acting on the bearing acts on the rotating shaft.

  Preferably, the cross-sectional area perpendicular to the direction of the bearing load in the friction member increases stepwise as the distance from the rotating shaft increases.

  Preferably, in the cross section of the friction member when it is cut by a plane including the axis of the rotation shaft and parallel to the direction of the bearing load, the surface of the friction member facing the rotation shaft is stepped.

  Preferably, the state monitoring device further includes a stay for fixing the friction member and the state monitoring sensor to the housing.

  More preferably, the state monitoring device further includes a vibration isolating material that blocks vibrations disposed between the state monitoring sensor and the stay.

  Preferably, during friction between the friction member and the rotary shaft, the wear amount of the friction member per rotation of the rotary shaft is larger than the wear amount of the bearing per rotation of the rotary shaft.

  Preferably, the state monitoring device further includes an arithmetic processing unit that receives an output of the state monitoring sensor and determines whether or not an abnormality has occurred in the bearing. The arithmetic processing unit determines that an abnormality has occurred in the bearing when the feature amount obtained from the state monitoring sensor transitions from a state smaller than the first threshold value to a larger state, and the feature amount and the first threshold value are determined. The amount of displacement of the rotating shaft is determined based on a comparison result with a larger second threshold value.

  Alternatively, the arithmetic processing unit determines the first threshold value based on the feature amount obtained from the state monitoring sensor during the first operation period, and the first operation in which the feature amount transitions to a state smaller than the first threshold value. The second threshold value is determined based on the feature amount obtained from the state monitoring sensor in the second operation period after the period. The arithmetic processing unit determines that an abnormality has occurred in the bearing when the feature amount obtained from the state monitoring sensor after the second operation period transits from a state smaller than the second threshold value to a larger state. The arithmetic processing unit is larger than the second threshold value based on the feature value obtained from the state monitoring sensor in the third operation period after the feature value transits from a state smaller than the second threshold value to a larger state. A third threshold value is determined, and a predetermined amount of displacement corresponding to the third threshold value is stored. The arithmetic processing unit displaces the rotation axis by a predetermined displacement amount when the feature amount obtained from the state monitoring sensor after the third operation period transitions from a state smaller than the third threshold value to a larger state. It is determined that

  A method according to another aspect of the present disclosure is a state monitoring method for detecting an abnormality of a bearing in which a stationary ring is fixed to a housing by a state monitoring device. The state monitoring device includes a friction member disposed so as to face the peripheral surface of the rotation shaft so that the degree of contact changes when the rotation shaft supported by the bearing is displaced with respect to the housing, and the state monitoring contacting the friction member A sensor. The state monitoring sensor is an AE sensor or an acceleration sensor. The friction member has a shape such that the contact area with the rotation shaft increases as the displacement amount of the rotation shaft increases. The state monitoring method includes a step of determining that an abnormality has occurred in the bearing when the feature amount obtained from the state monitoring sensor transitions from a state smaller than a first threshold value to a larger state, Determining a displacement amount of the rotating shaft based on a comparison result with a second threshold value larger than the threshold value.

  With the state monitoring device of the present invention, it is possible to detect anomalies with high accuracy in a low-speed operation bearing without being affected by an environment such as lubricating oil or water.

It is the figure which showed schematically the structure of the wind power generator to which the state monitoring apparatus according to embodiment of this invention is applied. It is a schematic diagram for demonstrating the direction of the bearing load concerning the bearing which supports a main axis | shaft. 1 is a diagram illustrating a configuration of a state monitoring device according to a first embodiment. It is a figure which shows one Example of a friction member. It is a figure which shows another Example of a friction member. It is a figure which shows another Example of a friction member. It is a figure which shows the measurement data of the state monitoring apparatus of Embodiment 1. FIG. 4 is a flowchart for explaining abnormality determination processing executed by the arithmetic processing device in the first embodiment. It is a figure which shows the structure of the state monitoring apparatus of the modification of Embodiment 1. FIG. It is a figure which shows the measurement data of the state monitoring apparatus of the modification of Embodiment 1. FIG. It is a figure which shows another Example of a friction member. It is a figure which shows the measurement data of the state monitoring apparatus of Embodiment 2. FIG. 9 is a flowchart for explaining the first half of an abnormality determination process executed by the arithmetic processing unit in the second embodiment. 9 is a flowchart for explaining the second half of the abnormality determination process executed by the arithmetic processing unit in the second embodiment. It is a figure which shows the measurement data of the state monitoring apparatus of the modification of Embodiment 2. FIG.

  Embodiments of the present invention will be described below with reference to the drawings. In the following drawings, the same or corresponding parts are denoted by the same reference numerals, and description thereof will not be repeated.

[Configuration of the entire wind power generator]
With reference to FIGS. 1-2, the structure of the wind power generator which is an example of the apparatus which can apply the state monitoring apparatus which concerns on this embodiment is demonstrated. The wind power generator is an example, and the state monitoring device according to the present embodiment can be applied to a bearing such as a railway vehicle or a spindle.

  FIG. 1 schematically shows a configuration of a wind turbine generator to which a state monitoring device according to an embodiment of the present invention is applied. Referring to FIG. 1, the wind power generator 10 includes a rotating shaft 20, a hub 25, a blade 30, a speed increaser 40, a generator 50, a control panel 52, and a power transmission line 54. The wind power generator 10 further includes a main shaft bearing (hereinafter simply referred to as a “bearing”) 60 and a data processing device 80. The step-up gear 40, the generator 50, the control panel 52, the bearing 60, and the data processing device 80 are stored in a nacelle 90, and the nacelle 90 is supported by a tower 92.

  The rotating shaft 20 is a main shaft of the wind power generator, is rotatably supported by a bearing 60, and is connected to the input shaft of the speed increaser 40 in the nacelle 90. The rotating shaft 20 transmits the rotational torque generated by the blade 30 receiving wind force to the input shaft of the speed increaser 40. The blade 30 is attached to the hub 25 at the tip of the rotating shaft 20, and converts wind force into rotating torque and transmits the rotating torque to the rotating shaft 20.

  The bearing 60 is fixed in the nacelle 90 and supports the rotary shaft 20 in a freely rotatable manner. The bearing 60 is configured by a rolling bearing. For example, self-aligning roller bearings can be used as shown in FIGS. 2 and 3, but they may be constituted by tapered roller bearings, cylindrical roller bearings, ball bearings or the like. These bearings may be single row or double row.

  The speed increaser 40 is provided between the rotary shaft 20 and the generator 50, and increases the rotational speed of the rotary shaft 20 to output to the generator 50. The generator 50 is connected to the output shaft of the speed increaser 40, and generates power by the rotational torque received from the speed increaser 40.

  The control panel 52 includes an inverter (not shown) and the like. The inverter converts the electric power generated by the generator 50 into a system voltage and frequency and outputs it to the power transmission line 54 connected to the system.

  A signal from the state monitoring sensor is transmitted to the data processing device 80 from the bearing 60 that supports the rotating shaft 20. Although the signal from the bearing 60 is representatively shown here, a signal from a state monitoring sensor also provided from another bearing is transmitted to the data processing device 80.

  FIG. 2 is a schematic diagram for explaining the direction of the bearing load applied to the bearing that supports the main shaft. Referring to FIG. 2, bearing 60 includes a bearing 60 </ b> A installed on the hub 25 side and a bearing 60 </ b> B provided on the speed increaser 40 side in FIG. 1.

  The gravity G acting on the blade 30 and the hub 25 acts on the tip of the rotating shaft 20. For this reason, the bearing load FA acts on the bearing 60A in the same direction as gravity. On the other hand, since the bearing 60A serves as a fulcrum, when the gravity G acts, the bearing load FB acts on the bearing 60B in the direction opposite to the gravity.

  Thus, the direction in which the bearing load acts on the bearing may vary depending on the place where it is used. However, if the place where the bearing is used is determined, the direction in which the bearing load acts is almost determined, so the direction in which the bearing load acts is known in advance when assembling the equipment using the bearing.

  A load region is generated in the outer ring of the bearing with respect to the direction in which the bearing load acts. Since the inner ring and rolling elements of the bearing are rotating, it is expected to wear evenly. However, since the outer ring of the bearing is fixed, the wear proceeds more in the load region. As a result, it can be considered that the rotating shaft is displaced in the direction of the bearing load.

  In the following embodiments, a state monitoring device capable of detecting the displacement of the rotating shaft will be described in detail. In this state monitoring device, a friction member that is more likely to be worn than the rotating shaft is disposed on the bearing load acting side (load region side) with respect to the bearing, and the rotation of the bearing is based on AE or vibration generated in the friction member. Detect shaft displacement.

[Embodiment 1]
FIG. 3 is a diagram illustrating a configuration of the state monitoring apparatus according to the first embodiment. Referring to FIG. 3, state monitoring apparatus 100 according to the first embodiment monitors a state such as wear of bearing 160, and includes a friction member 146 and a state monitoring sensor 145 in contact with friction member 146. Prepare. The friction member 146 is disposed so as to face the peripheral surface of the rotary shaft 20 so that the degree of contact changes when the rotary shaft 20 supported by the bearing 160 is displaced in the bearing load direction. The shape of the friction member 146 will be described later. The state monitoring sensor 145 is an AE sensor or an acceleration sensor. The bearing 160 corresponds to the bearing 60A in FIG.

  The bearing 160 is surrounded by the rotating shaft 20, the housing 120, and the bearing retainer 121. Although not shown, the housing 120 is fixed to a nacelle or the like. Bearing 160 includes an inner ring 131, an outer ring 132, and a plurality of rolling elements 133 (for example, barrel-shaped rollers). The inner ring 131 has a rolling surface in contact with the plurality of rolling elements 133 on its outer peripheral surface, and the outer ring 132 has a rolling surface in contact with the plurality of rolling elements 133 on its inner peripheral surface. ing.

  The inner ring 131 is fitted with the rotary shaft 20 on the inner side of the rolling surface, and the outer ring 132 is fitted with the housing 120 on the outer side of the rolling surface. The inner ring 131 and the rotating shaft 20 are rotatably provided as a unit. In the bearing 160, an outer ring 132 that is a fixed ring is fixed to the housing 120. The friction member 146 is disposed so as to face the peripheral surface of the rotary shaft 20 so that the degree of contact changes when the rotary shaft 20 supported by the bearing 160 is displaced in the bearing load direction with respect to the housing 120. The state monitoring sensor 145 is an AE sensor or an acceleration sensor. The bearing 160 corresponds to the bearing 60A in FIG.

  The friction member 146 is disposed on the rotating shaft 20 on the side on which the bearing load FA acting on the bearing 160 acts (the load region side of the outer ring).

  The friction member 146 is preferably made of a material that easily wears and easily generates AE and vibration acceleration. The friction member 146 is more preferably made of a material that does not easily damage the mating member (rotating shaft 20). Further, in order to detect the wear of the bearing 160, the friction member 146 is configured so that the amount of wear of the friction member 146 per rotation of the rotary shaft 20 is equal to that of the rotary shaft 20 when the friction member 146 and the rotary shaft 20 are frictioned. A bearing that is larger than the wear amount of the bearing 160 (inner ring, outer ring, rolling element) per rotation is selected. For example, as the friction member 146, a carbon material, a resin, a resin in which various reinforcing materials are combined, a copper alloy, an aluminum alloy, a titanium alloy, a metal sintered body, a metal powder compression molding, and a resin powder compression molding are used. be able to.

  The state monitoring apparatus 100 further includes a stay 141, a vibration isolation material 143, a vibration isolation material cover 142, and an arithmetic processing device 81. The stay 141 fixes the friction member 146 and the state monitoring sensor 145 to the housing 120 and the bearing retainer 121 of the bearing 60. The vibration isolator 143 is disposed between the state monitoring sensor 145 and the stay 141, and blocks or attenuates AE and vibration transmitted from the stay 141 to the sensor.

  The arithmetic processing unit 81 receives the output of the state monitoring sensor 145 and determines whether or not an abnormality has occurred in the bearing. The arithmetic processing unit 81 determines that an abnormality has occurred in the bearing 160 when the feature amount obtained from the state monitoring sensor 145 has transitioned from a state smaller than the threshold value A to a larger state (FIGS. 7 and 8). (See FIG. 10). The arithmetic processing device 81 can be installed, for example, inside the data processing device 80 of FIG. A computer that receives data from the data processing device 80 at a remote location may be used as the arithmetic processing device 81.

  As described above, the state monitoring device 100 is a device that detects the displacement of the rotating shaft 20. For this reason, the friction member 146 is placed in contact with or close to the rotating shaft 20. A state monitoring sensor 145 that is an AE sensor or an acceleration sensor is bonded to the friction member 146. The stay 141 fixes the state monitoring sensor 145 to the housing 120 or the bearing retainer 121. The friction member 146 is installed at a position where wear proceeds with the displacement of the rotating shaft 20.

  As the operating time of the bearing 160 becomes longer, the rolling element 133, the inner ring 131, and the outer ring 132 are worn. When these wears occur, the rotary shaft 20 is displaced in the direction in which the bearing load acts due to the bearing load. That is, the displacement of the rotating shaft 20 occurs as the distance between the inner ring 131 and the outer ring 132 of the bearing 160 changes.

  When the rotating shaft 20 is displaced, the friction member 146 is worn and AE and vibration acceleration are generated, and the state monitoring sensor 145 directly adhered to the friction member 146 can detect the displacement of the rotating shaft 20 with high sensitivity. By detecting this displacement, it is possible to detect with high sensitivity that the bearing 160 has been damaged due to wear or the like.

  Further, the state monitoring apparatus 100 includes a vibration isolating material 143 for isolating vibration between the state monitoring sensor 145 and the stay 141 and a vibration isolating material cover 142. The anti-vibration material 143 can block AE and vibration acceleration transmitted to the state monitoring sensor 145 via the stay 141. For this reason, it is difficult for the state monitoring sensor 145 to detect AE and vibration occurring in the bearing 160 and other parts. For this reason, AE and vibration acceleration generated from the friction member 146 can be measured with higher sensitivity.

  FIG. 4 is a view showing an example (friction member 146a) of the friction member 146. As shown in FIG. FIG. 4A shows a plan view of the friction member 146a. FIG. 4B shows a side view of the friction member 146a when viewed from a direction perpendicular to the axis 21 of the rotary shaft 20 and the bearing load direction. FIG. 4C shows a side view of the friction member 146a when viewed from the direction of the axis 21 of the rotating shaft 20. FIG.

  Referring to FIG. 4, the friction member 146a has a substantially conical shape, and its side surface is stepped. In other words, the friction member 146a gradually decreases in height from the bottom surface as it goes from the top to the end of the cone. The friction member 146 a having a substantially conical shape is arranged such that its axial direction coincides with the direction of the bearing load and the top faces the rotating shaft 20.

  FIG. 5 is a view showing another embodiment of the friction member 146 (friction member 146b). FIG. 5A shows a plan view of the friction member 146b. FIG. 5B shows a side view of the friction member 146b when viewed from a direction perpendicular to the axis 21 of the rotating shaft 20 and the direction of the bearing load. FIG. 5C shows a side view of the friction member 146b when viewed from the direction of the axis 21 of the rotating shaft 20. FIG.

  Referring to FIG. 5, the friction member 146b has a rectangular shape in plan view, and is formed in a downward staircase shape from the central portion toward the short side so that the central portion in the longitudinal direction is the top. In other words, the friction member 146b has a rectangular bottom surface, and the height from the bottom surface decreases stepwise from the central portion in the longitudinal direction toward the short side. The friction member 146b is disposed so that the direction perpendicular to the bottom surface coincides with the direction of the bearing load and the top faces the rotation shaft 20.

  A surface of the friction members 146a and 146b facing the rotation shaft 20 in a cross section (see FIG. 3) of the friction members 146a and 146b when cut along a plane that includes the axis 21 of the rotation shaft 20 and is parallel to the bearing load direction. Is stepped. The surface facing the rotating shaft 20 in each stage is orthogonal to the direction of the bearing load.

  Note that, when viewed from the direction of the axis 21 of the rotary shaft 20, the friction member 146a shown in FIG. 4 is stepped, whereas the friction member 146b shown in FIG. 5 is rectangular. Therefore, the friction member 146b shown in FIG. 5 can save space compared to the friction member 146a shown in FIG.

  Here, the step including the tops of the friction members 146a and 146b is the first step, the lower step is the second step, the lower step is the third step, and so on. A peripheral surface of a portion of the rotating shaft 20 facing the friction members 146 a and 146 b is parallel to the axis 21 of the rotating shaft 20. Therefore, when the first stage of the friction member 146a is scraped due to wear with the rotary shaft 20, and the rotary shaft 20 starts to contact the second stage of the friction member 146a, the contact area between the friction member 146a and the rotary shaft 20 is not sufficient. Increase continuously. When the second stage of the friction member 146a is cut and the rotating shaft 20 starts to contact the third stage of the friction member 146a, the contact area between the friction member 146a and the rotating shaft 20 increases discontinuously. The same applies to the friction member 146b. As described above, the friction members 146a and 146b have such shapes that the contact area with the rotating shaft 20 increases stepwise as the displacement amount of the rotating shaft 20 increases.

  The contact area between the friction members 146a and 146b and the rotating shaft 20 correlates with the feature amount (AE wave or vibration acceleration amplitude, etc.) obtained from the state monitoring sensor 145. Therefore, when the contact area between the friction members 146a and 146b and the rotating shaft 20 increases stepwise, the feature amount (AE wave or vibration acceleration amplitude, etc.) obtained from the state monitoring sensor 145 also increases stepwise. That is, the timing at which the feature amount obtained from the state monitoring sensor 145 increases stepwise matches the timing at which one of the friction members 146a and 146b is scraped off due to wear and the wear of the next step is started. To do.

  When the characteristic amount obtained from the state monitoring sensor 145 transits from a state smaller than the threshold value A, B (or A1, B1, B2) to a larger state, the arithmetic processing unit 81 causes the friction member 146a, 146b to It is determined that it is the timing when the wear of the step corresponding to the threshold value is started (see FIGS. 7, 8, and 10). The arithmetic processing unit 81 stores in advance the displacement amount M of the rotating shaft 20 corresponding to each threshold value, and compares the feature amount obtained from the state monitoring sensor 145 with the threshold value, thereby rotating the rotating shaft 20. The amount of displacement is determined. The displacement amount M stored in the arithmetic processing unit 81 is determined in advance based on the initial value of the distance between the friction members 146a, 146b and the rotary shaft 20 and the height of each step in the friction members 146a, 146b. Here, when the surface corresponding to the rotating shaft 20 in each step is the upper surface of the step, the height of each step of the friction member 146 is the height of the upper surface of the step relative to the upper surface of the step below the step. means.

  FIG. 6 is a view showing still another embodiment (friction member 146 c) of the friction member 146. Referring to FIG. 6, the friction member 146c is substantially conical like the friction member 146a shown in FIG. 4, and its side surface is stepped (two steps). In the friction member 146c, the height t1 of the first step is 0.04 mm, and the total value t2 of the heights of the first and second steps is 0.08 mm.

FIG. 7 is a diagram illustrating measurement data of the state monitoring apparatus according to the first embodiment. The data of FIG. 7 simulates the case where the direction of the bearing load is vertically downward like the bearing 60A of FIG. 2, and is obtained under the following measurement conditions.
<Measurement conditions>
Device configuration: Configuration shown in FIG. 3 Friction member shape: Shape shown in FIG. 6 Friction member material: Carbon material state detection sensor: AE (Envelope-processed time waveform is voltage output)
Bearing: Spherical roller bearing (inner diameter 560mm, outer diameter 820mm, width 195mm)
Displacement of rotating shaft: Up to 0.1 mm, observed with another displacement meter for comparison Rotating speed: 20 rev / min (Time of one rotation 3 seconds)
Sampling rate: 100 kHz
Data length: 15 seconds Measurement interval: 10 minutes In the first embodiment, the friction member 146c is not brought into contact with the rotating shaft 20 at the start of operation, and the relative distance (the initial value of the distance between the friction member 146c and the rotating shaft 20). ) Was set to 0.06 mm. In order to reproduce the state in which the bearing 160 in the normal state starts to increase the displacement of the rotating shaft 20 during the operation, the load is gradually increased during the constant rotation speed operation. FIG. 7 shows the displacement X1, the effective value E1, and the variation coefficient C1. The displacement X1 indicates a displacement in which the bearing load direction of the rotating shaft 20 is positive. The effective value E1 is a square root of an average value of values obtained by squaring each sampling value of the output of the state monitoring sensor 145 included in the data length of 15 seconds. The variation coefficient C1 is obtained by dividing the standard deviation of the sampling value by the arithmetic average and represents a relative variation.

  The plot of the effective value E1 and the coefficient of variation C1 is obtained by plotting values calculated for a data length of 15 seconds at intervals of 10 minutes, and the displacement X1 of the rotating shaft 20 is in the vicinity of the friction member 146c. It is an instantaneous value measured using a displacement meter.

  Wear of the bearing 160 proceeds from about 2 hours of operation time, and the displacement X1 of the rotary shaft 20 gradually increases. When the friction member 146c is brought close to the rotary shaft 20 without being brought into contact therewith, the distance between the friction member 146c and the rotary shaft 20 can be accurately grasped at the time of installation so that it can be regarded as abnormal if the friction member 146c and the rotary shaft 20 come into contact. The distance is adjusted to the amount of change between the inner ring and the outer ring gap of the bearing which is detected as abnormal. Here, the distance is set to 0.06 mm.

  When the displacement X1 of the rotating shaft 20 reaches 0.06 mm, the first stage of the friction member 146c and the rotating shaft 20 come into contact with each other, and the effective value E1 increases. The effective value E1 at this time is a value corresponding to the size of the contact area between the friction member 146c and the rotating shaft 20. The contact area is substantially equal to the cross-sectional area perpendicular to the bearing load direction in the first stage of the friction member 146c.

  In the first embodiment, the threshold A is based on the effective value E1 obtained in the initial period (first threshold generation period T1) in which the friction member 146c at the start of operation is not in contact with the rotating shaft 20. Is determined. The threshold A is a value compared with the effective value E1 in order to detect an increase in the effective value E1 due to the start of contact between the first stage of the friction member 146c and the rotating shaft 20. For example, the threshold value A can be determined in consideration of the average value and standard deviation of the initial period (first threshold value generation period T1). The friction member 146c immediately after the start of operation is not worn because it is not in contact with the rotating shaft. This period without wear is suitable as a period for generating the threshold value A for detecting an abnormality because there is no abnormality in the bearing and the level of AE and vibration acceleration and its fluctuation are small.

  Until the displacement X1 of the rotating shaft 20 changes from 0.06 mm to 0.1 mm, the rotating shaft 20 continues to be displaced while contacting only the first stage of the friction member 146c. During this time, there is no change in the contact area between the friction member 146c and the rotating shaft 20. Therefore, the effective value E1 is stabilized at a value corresponding to the contact area.

  When the displacement X1 of the rotating shaft 20 reaches 1.00 mm, the rotating shaft 20 starts to contact the second stage of the friction member 146c, and the effective value E1 increases. The effective value E1 at this time is a value corresponding to the size of the contact area between the second stage of the friction member 146c and the rotating shaft 20. The contact area is substantially equal to the cross-sectional area perpendicular to the direction of the second stage bearing load in the friction member 146c.

  In the present embodiment, the effective value E1 obtained in the period during which the effective value E1 until the displacement X1 of the rotating shaft 20 changes from 0.06 mm to 0.1 mm is stable (second threshold value generation period T2) is obtained. Based on this, the threshold value B is determined. The threshold value B is a value that is compared with the effective value E1 in order to detect an increase in the effective value E1 due to the start of contact between the second stage of the friction member 146c and the rotating shaft 20.

  The threshold value B is an effective value E1 when the rotary shaft 20 is in contact with the first stage of the friction member 146c, and an effective value E1 when the rotary shaft 20 is in contact with the second stage of the friction member 146c. It is preferable that the value is determined between. Sa is the contact area between the rotating shaft 20 and the friction member 146c when the rotating shaft 20 is in contact with the first stage of the friction member 146c, and the rotating shaft 20 is in contact with the second stage of the friction member 146c. The contact area between the rotary shaft 20 and the friction member 146c is Sb. At this time, the ratio between the effective value E1 when the rotary shaft 20 is in contact with the first stage of the friction member 146c and the effective value E1 when the rotary shaft 20 is in contact with the second stage of the friction member 146c. Is approximately equal to the ratio of Sa to Sb. Therefore, based on the effective value E1 when the rotating shaft 20 is in contact with the first stage of the friction member 146c, the effective value E1 is estimated when the rotating shaft 20 is in contact with the second stage of the friction member 146c. The threshold value B can be determined in consideration of the estimated value. Therefore, the period in which the rotary shaft 20 contacts the first stage of the friction member 146c and the effective value E1 is stably output is suitable as the period for generating the threshold value B. The threshold value B is determined based on, for example, the average value of the effective values E1 during the period and the ratio between Sa and Sb. The ratio of Sa and Sb is, for example, the ratio between the cross-sectional area perpendicular to the bearing load direction at the first stage of the friction member 146c and the cross-sectional area perpendicular to the bearing load direction at the second stage of the friction member 146c. It is almost the same.

  FIG. 8 is a flowchart for explaining the abnormality determination process executed by the arithmetic processing unit in the first embodiment. FIG. 8 shows a flowchart when the friction member 146c shown in FIG. 6 is used.

  3 and 6 to 8, first, in step S1, the arithmetic processing unit 81 samples the output signal of the state monitoring sensor 145 in the initial operation period (first threshold value generation period T1). To obtain initial value data. In step S2, the arithmetic processing unit 81 calculates an average value, standard deviation σ, and the like of the initial value data obtained in the initial period, and determines the threshold A based on these. For example, the average value + 3σ can be set as the threshold value A. This initial period is usually a period in which no displacement occurs in the rotating shaft due to wear of the bearing, and can be determined experimentally as appropriate. The arithmetic processing unit 81 stores an initial value (for example, 0.06 mm) of the distance between the friction member 146 and the rotating shaft 20 as the displacement amount M1 of the rotating shaft 20 corresponding to the threshold value A.

  In step S <b> 3, the arithmetic processing unit 81 monitors the subsequent effective value E and determines whether or not the effective value E is greater than the threshold value A. If E> A is not satisfied (NO in S3), the process of step S3 is executed again. On the other hand, if E> A (YES in S3), the process proceeds to step S4. In step S4, the arithmetic processing unit 81 determines that an abnormality has occurred in the bearing 160, and the rotating shaft 20 has been displaced by the displacement amount M1 (the initial value of the distance between the friction member 146 and the rotating shaft 20), and if necessary. Record and notify.

  By defining the threshold value A in this way, it is possible to avoid erroneously detecting the occurrence of a bearing abnormality due to background noise. Further, in the first embodiment, it is accurately detected that the amount of displacement of the rotary shaft 20 from the start of operation (the amount of change in the gap between the inner ring and the outer ring due to bearing wear) has reached M1 (for example, 0.06 mm). it can.

  Next, in step S5, the arithmetic processing unit 81 determines whether or not the feature amount change ΔE is smaller than the determination value K1. This is because it is preferable to generate the threshold value B after the value of E1 has settled after exceeding the threshold value A in FIG.

  While ΔE <K1 is not satisfied (NO in S5), the process returns to step S5 again. On the other hand, if ΔE <K1 is satisfied (YES in S5), the process proceeds to step S6.

  In step S6, the arithmetic processing unit 81 samples the output signal from the state monitoring sensor 145 in the second threshold value generation period T2 to obtain data for generating the threshold value B. In step S7, the arithmetic processing unit 81 calculates an average value of the data obtained in the second threshold value generation period T2, and determines the threshold value B based on the calculated average value. For example, when the sectional area perpendicular to the bearing load direction at the first stage of the friction member 146c is Sc and the sectional area perpendicular to the bearing load direction at the second stage of the friction member 146c is Sd, 0.5 × (1 + Sd / Sc) × average value can be the threshold value B. The second threshold value generation period T2 starts after ΔE <K1 is established, and the end point can be determined experimentally as appropriate. The arithmetic processing unit 81 uses the displacement amount M1 of the rotating shaft 20 corresponding to the threshold value A and the height t1 of the first stage of the friction member 146c as the displacement amount M2 of the rotating shaft 20 corresponding to the threshold value B (FIG. 6)) = 0.04 mm and the total value (for example, 0.10 mm) is stored.

  In step S8, the arithmetic processing unit 81 monitors the subsequent effective value E and determines whether or not the effective value E is greater than the threshold value B. If E> B is not satisfied (NO in S8), the process of step S8 is executed again. On the other hand, if E> B (YES in S8), the process proceeds to step S9. In step S9, the arithmetic processing unit 81 determines that the rotary shaft 20 has been displaced by a displacement amount M2 corresponding to the threshold value B, performs recording and notification as necessary, and ends the process in step S10.

  As described above, the state monitoring device 100 includes the friction member 146 disposed so as to face the circumferential surface of the rotary shaft 20 so that the degree of contact changes when the rotary shaft 20 supported by the bearing 160 is displaced. A state monitoring sensor 145 in contact with the friction member 146. The friction member 146 has a shape such that the contact area with the rotation shaft 20 increases as the displacement amount of the rotation shaft 20 increases. The feature amount output from the state monitoring sensor 145 varies according to the contact area between the friction member 146 and the rotating shaft 20. Therefore, according to the above configuration, the displacement amount of the rotating shaft 20 can be determined by monitoring the feature amount output from the state monitoring sensor 145.

  The arithmetic processing unit 81 determines that an abnormality has occurred in the bearing 160 when (i) the feature amount obtained from the state monitoring sensor 145 has shifted from a state smaller than the threshold value A to a larger state, and (ii) Based on the comparison result between the feature amount and the threshold value B greater than the threshold value A, the displacement amount of the rotating shaft 20 is determined. Specifically, the arithmetic processing unit 81 stores a predetermined displacement amount M2 corresponding to the threshold value B, and rotates when the feature value changes from a state smaller than the threshold value B to a larger state. It is determined that the shaft 20 has been displaced by the displacement amount M2. Thereby, the amount of displacement of the rotating shaft 20 from the start of operation (the amount of change in the gap between the inner ring and the outer ring due to bearing wear) can be accurately detected.

[Modification of Embodiment 1]
In the modification of the first embodiment, an example will be described in which a similar detection process is performed on a sliding bearing instead of a rolling bearing.

  FIG. 9 is a diagram illustrating a configuration of a state monitoring apparatus according to a modification of the first embodiment. Referring to FIG. 9, state monitoring apparatus 101 includes a friction member 146 and a state monitoring sensor 145 that comes into contact with friction member 146. The friction member 146 is disposed so as to face the circumferential surface of the rotary shaft 20 so that the degree of contact changes when the rotary shaft 20 supported by the bearing 160A, which is a plain bearing, is displaced. The state monitoring sensor 145 is an AE sensor or an acceleration sensor.

  The bearing 160 </ b> A is surrounded by the rotary shaft 20, the housing 220, and the bearing retainer 221. The bearing 160A has a back metal integrated structure, a sliding member is disposed on the inner side of the back metal, and the rotary shaft 20 penetrates further on the inner side. The bearing 160A is fitted with the housing 220 on the outside. For the sliding member arranged inside the back metal, for example, a resin material such as polytetrafluoroethylene (PTFE) can be used. Moreover, you may use the porous sintered compact which has a metal powder as a main component as a sliding member. It is. Since the pores of the sliding member are impregnated with oil, the oil circulates inside the bearing and plays a role of lubrication during operation.

  The friction member 146 is disposed on the side on which the bearing load FA acting on the bearing 160A acts (the load region side of the back metal) with respect to the rotating shaft 20. Since friction member 146, vibration isolator 143, vibration isolator cover 142, and stay 141 are the same as those in the first embodiment, description thereof will not be repeated.

FIG. 10 is a diagram illustrating measurement data of the state monitoring device according to the modification of the first embodiment. The data in FIG. 10 is obtained under the following measurement conditions.
<Measurement conditions>
Device configuration: Configuration shown in FIG. 9 Friction member shape: Shape shown in FIG. 6 Friction member material: Carbon material state detection sensor: AE (Envelope-processed time waveform is voltage output)
Bearing material: PTFE composite material (inner diameter 100mm, width 50mm)
Load: 50kN
Rotation speed: 20 rotations / minute (one rotation time 3 seconds)
Sampling rate: 100 kHz
Data length: 15 seconds Measurement interval: 15 hours (hour)
FIG. 10 shows the displacement X2, the effective value E2, and the variation coefficient C2. The displacement X2 indicates a displacement in which the bearing load direction of the rotating shaft 20 is positive. The effective value E2 is a square root of an average value of values obtained by squaring each sampling value of the output of the state monitoring sensor 145 included in the data length of 15 seconds. The variation coefficient C2 is obtained by dividing the standard deviation of the sampling value by the arithmetic average, and represents a relative variation.

  The plot of the effective value E2 and the coefficient of variation C2 is obtained by plotting values calculated for a data length of 15 seconds at 15-hour intervals, and the displacement X2 of the rotating shaft 20 is in the vicinity of the friction member 146 for comparison. These are instantaneous values measured using other displacement meters. In order to reproduce the state in which the bearing in the normal state starts to increase the displacement between the inner and outer rings during the operation, the load is gradually increased during the constant rotation speed operation.

  In the bearing 160A, wear rapidly increases from about 270 hours (hours) in operation time, and the displacement X2 of the rotary shaft 20 gradually increases. In the modification of the first embodiment, based on the effective value E2 obtained in the initial period (first threshold value generation period T1) in which the friction member 146 at the beginning of operation is not in contact with the rotating shaft 20, The threshold value A is determined. For example, the threshold value A can be determined in consideration of the average value and standard deviation of the initial period (first threshold value generation period T1).

  Further, the threshold value B is determined based on the effective value E2 obtained in a period during which the effective value E2 exceeds the threshold value A and is stable (second threshold value generation period T2). For example, based on the average value of this period (second threshold value generation period T2), the first-stage cross-sectional area Sc of the friction member 146c, and the second-stage cross-sectional area Sd of the friction member 146c, the threshold value B can be determined.

  Note that threshold value A and B calculation processing and abnormality determination processing are the same as the processing in the flowchart of FIG.

In this way, a similar state monitoring device can be realized for the sliding bearing.
[Embodiment 2]
In the first embodiment, the friction member 146 immediately after the start of operation is not worn because it is not in contact with the rotating shaft 20. However, if there is too much space between the rotary shaft 20 and the friction member 146, the friction member 146 will not come into contact with the rotary shaft 20 until a while after the rotary shaft 20 starts to be displaced. There is a possibility. Therefore, it is difficult to set the gap between the rotating shaft 20 and the friction member 146.

  In the second embodiment, a state monitoring method is used in which the friction member 146 is brought into contact with the rotating shaft 20 immediately after the start of operation. The configuration of the apparatus is the same as that described in FIG.

  FIG. 11 is a view showing still another example of the friction member 146 (friction member 146d). Referring to FIG. 11, the friction member 146d has a substantially conical shape and has a stepped shape (three steps) as in the friction member 146a shown in FIG. The first stage height t3 of the friction member 146d is 0.06 mm, and the total height t4 of the first stage and the second stage of the friction member 146c is 0.10 mm.

  FIG. 12 is a diagram illustrating measurement data of the state monitoring apparatus according to the second embodiment. The data in FIG. 12 is obtained under the same measurement conditions as in FIG. 7 except that the friction member 146d having the shape shown in FIG. 12 is used. Furthermore, the second embodiment is different from the first embodiment in that the friction member 146d is brought into contact with the rotating shaft 20 from the beginning of operation. In FIG. 12, a displacement X3, an effective value E3, and a variation coefficient C3 are shown. The displacement X3 indicates a displacement in which the bearing load direction of the rotating shaft 20 is positive. The effective value E3 is a square root of an average value of values obtained by squaring each sampling value of the output of the state monitoring sensor 145 included in the data length of 15 seconds. The variation coefficient C3 is obtained by dividing the standard deviation of the sampling value by the arithmetic average and represents a relative variation.

  As shown in FIG. 12, the operation period includes a preliminary operation period T0 at the beginning of operation, a first threshold value generation period T1, and a second threshold value generation period T2.

  When the friction member 146d is brought into contact with the rotary shaft 20 at the beginning of the operation, the contact force is determined by the rigidity of the component supporting the friction member 146d such as the stay 141. Therefore, in the preliminary operation period T0, the friction member 146d is greatly worn immediately after the start of the operation, but the progress of wear of the friction member 146d is stagnated due to a decrease in contact force accompanying the wear. Migrate to In order to determine the transition to the first threshold value generation period T1, the threshold value Z is determined based on the sampled feature amount data such as AE and vibration acceleration in the initial stage of the preliminary operation period T0. Then, based on the fact that the feature amount has dropped below the threshold value Z, it is determined that the preliminary operation period T0 has shifted to the first threshold value generation period T1.

  The period until the stagnation (preliminary operation period T0) is several hundred to several tens of thousands of rotations from the start of operation, and there is no abnormality in the bearing. However, as the friction member 146 wears, the level of AE and vibration acceleration And the variation is great.

  On the other hand, during the period in which the wear is stagnant (first threshold value generation period T1), the bearing has no abnormality and the level and fluctuation of AE and vibration acceleration are small. Suitable as a period.

  In FIG. 12, the displacement X3 of the rotating shaft 20 gradually increases from an operation time of 2 hours (hour). The timing at which the clearance between the inner ring and the outer ring of the bearing begins to increase by generating a threshold value A1 for detecting anomalies in the vicinity of 1.5 hours (hours) when the effective value and coefficient of variation are low and stable. Can be detected accurately.

  Until the displacement X3 of the rotating shaft 20 reaches 0.06 mm, the rotating shaft 20 continues to be displaced while contacting only the first stage of the friction member 146d. During this time, there is no change in the contact area between the friction member 146d and the rotating shaft 20. Therefore, the effective value E3 is stabilized at a value corresponding to the contact area.

  When the displacement X3 of the rotating shaft 20 reaches 0.06 mm, the rotating shaft 20 starts to contact the second stage of the friction member 146d, and the effective value E3 further increases. The effective value E3 at this time is a value corresponding to the size of the contact area between the second stage of the friction member 146d and the rotating shaft 20. The contact area is substantially equal to the cross-sectional area perpendicular to the bearing load direction in the second stage of the friction member 146d.

  When the rotary shaft 20 is further displaced and the displacement X3 of the rotary shaft 20 reaches 0.10 mm, the rotary shaft 20 starts to contact the third stage of the friction member 146d, and the effective value E3 further increases. The effective value E3 at this time is a value corresponding to the size of the contact area between the third stage of the friction member 146d and the rotary shaft 20. The contact area is substantially equal to the cross-sectional area perpendicular to the bearing load direction at the third stage of the friction member 146c.

  In the present embodiment, the threshold value is based on the effective value E3 obtained in the period (second threshold value generation period T2) until the displacement X3 becomes 0.06 mm after the rotation shaft 20 starts to be displaced. B1 and B2 are determined. The threshold value B1 is a value that is compared with the effective value E3 in order to detect an increase in the effective value E3 due to the start of contact between the second stage of the friction member 146d and the rotating shaft 20. The threshold value B2 is a value compared with the effective value E3 in order to detect an increase in the effective value E3 due to the start of contact between the third stage of the friction member 146d and the rotating shaft 20.

  The threshold value B1 is, for example, the average value of the effective value E1 of the second threshold value generation period T2, the first level and the second level of the friction member 146d, as with the threshold value B of the first embodiment. It is determined based on the ratio of the cross-sectional areas.

  The threshold value B2 is an effective value E3 when the rotating shaft 20 is in contact with the second stage of the friction member 146d, and an effective value E3 when the rotating shaft 20 is in contact with the third stage of the friction member 146d. It is preferable that the value is determined between. Let Se be the contact area between the rotating shaft 20 and the friction member 146d when the rotating shaft 20 is in contact with the first stage of the friction member 146d. Let Sf be the contact area between the rotating shaft 20 and the friction member 146d when the rotating shaft 20 is in contact with the second stage of the friction member 146d. Let Sg be the contact area between the rotating shaft 20 and the friction member 146d when the rotating shaft 20 is in contact with the third stage of the friction member 146d. At this time, the ratio between the effective value E3 when the rotating shaft 20 is in contact with the first stage of the friction member 146d and the effective value E3 when the rotating shaft 20 is in contact with the second stage of the friction member 146c. Is approximately equal to the ratio of Se and Sf. Furthermore, the ratio between the effective value E3 when the rotating shaft 20 is in contact with the first stage of the friction member 146d and the effective value E3 when the rotating shaft 20 is in contact with the third stage of the friction member 146d is , Approximately equal to the ratio of Se and Sg. Therefore, based on the effective value E3 when the rotating shaft 20 is in contact with the first stage of the friction member 146d, the effective value E3 when the rotating shaft 20 is in contact with the second stage of the friction member 146d and the rotation The effective value E3 can be estimated when the shaft 20 is in contact with the third stage of the friction member 146d. Then, the threshold value B2 can be determined in consideration of the estimated value. Therefore, a period during which the effective value E1 is stably output when the rotating shaft 20 is in contact with the first stage of the friction member 146d is suitable as a period for generating the threshold value B2. The threshold value B2 is determined based on, for example, the average value of the effective values E1 in the period and the ratio of Se, Sf, and Sg. The ratio of Se, Sf, and Sg is substantially the same as the ratio of the cross-sectional area perpendicular to the bearing load direction in each of the first to third stages of the friction member 146d.

  FIG. 13 is a flowchart for explaining the first half of the abnormality determination process executed by the arithmetic processing unit in the second embodiment. FIG. 14 is a flowchart for explaining the second half of the abnormality determination process executed by the arithmetic processing unit in the second embodiment. 13 and 14 show a flowchart when the friction member 146d shown in FIG. 11 is used.

  3, 11 to 13, and 14, first, in step S <b> 11, the arithmetic processing unit 81 samples the output signal of the state monitoring sensor 145 in the initial operation period (initial stage of the preliminary operation period T <b> 0). To obtain initial value data. In step S12, the arithmetic processing unit 81 calculates an average value, standard deviation σ, and the like from the initial value data obtained in the initial period, and determines the threshold value Z based on these values. For example, the average value −3σ or 1/10 of the average value can be set as the threshold value Z. The initial period is a period in which the rotation shaft 20 is not normally displaced due to wear of the bearing, and the friction member 146d is in contact with the rotation shaft 20 and AE is generated in the friction member 146d.

  In step S13, the arithmetic processing unit 81 determines whether or not the effective value E of the feature amount obtained from the state monitoring sensor 145 is smaller than the threshold value Z. While E <Z is not satisfied (NO in S13), the preliminary operation period T0 in FIG. 12 has not ended, and the transition is made to the first threshold value generation period T1 for determining the threshold value A1. Since there is not, the process of S13 is performed again.

  If E <Z is satisfied in step S13 (YES in S13), the arithmetic processing unit 81 determines whether or not the feature amount change ΔE is smaller than the determination value K0 in step S14. This is because, in FIG. 12, it is preferable to generate the threshold value A1 after the value of E3 has settled down.

  While ΔE <K0 is not satisfied (NO in S14), the process returns to step S13 again. On the other hand, if ΔE <K0 is satisfied (YES in S14), the process proceeds to step S15.

  In step S15, the arithmetic processing unit 81 samples the output signal of the state monitoring sensor 145 in the first threshold value generation period T1, and obtains data for generating the threshold value A1. In step S16, the arithmetic processing unit 81 calculates an average value, standard deviation σ, and the like of the data obtained during the first threshold value generation period T1, and determines the threshold value A1 based on these values. For example, the average value + 3σ can be set as the threshold value A1. The first threshold value generation period T1 starts after E <Z and ΔE <K0 is satisfied, and the end point can be determined experimentally as appropriate.

  In step S17, the arithmetic processing unit 81 monitors the subsequent effective value E and determines whether or not the effective value E is greater than the threshold value A1. If E> A1, the process of step S17 is executed again. If E> A1, the process proceeds to step S18. In step S18, the arithmetic processing unit 81 determines that an abnormality has occurred in the bearing 160, and performs recording and notification as necessary.

  Next, in step S19, the arithmetic processing unit 81 determines whether or not the feature amount change ΔE is smaller than the determination value K1. This is because it is preferable to generate the threshold values B1 and B2 after the value of E3 has settled after exceeding the threshold value A1 in FIG.

  While ΔE <K1 is not satisfied (NO in S19), the process is returned to step S19 again. On the other hand, if ΔE <K1 is established (YES in S19), the process proceeds to step S20.

  In step S20, the arithmetic processing unit 81 samples the output signal from the state monitoring sensor 145 in the second threshold value generation period T2, and obtains data for generating the threshold values B1 and B2. In step S21, the arithmetic processing unit 81 calculates the average value of the data obtained in the second threshold value generation period T2, and determines the threshold values B1 and B2 based on the calculated average value. For example, when the cross-sectional area orthogonal to the bearing load direction in the first stage of the friction member 146d is Sh and the cross-sectional area orthogonal to the bearing load direction in the second stage of the friction member 146d is Si, 0.5 × (1 + Si / Sh) × average value can be the threshold value B1. Furthermore, when the cross-sectional area orthogonal to the bearing load direction at the third stage of the friction member 146d is Sj, the threshold value B2 can be 0.5 × {(Si + Sj) / Sh} × average value. The second threshold value generation period T2 starts after ΔE <K1 is established, and the end point can be determined experimentally as appropriate.

  The arithmetic processing unit 81 stores the first stage height t3 (see FIG. 11) = 0.06 mm of the friction member 146d as the displacement amount M3 of the rotating shaft 20 corresponding to the threshold value B1. Further, the arithmetic processing unit 81 uses the total amount t4 (see FIG. 11) of the first and second heights of the friction member 146d as the displacement amount M4 of the rotating shaft 20 corresponding to the threshold value B2 = 0. 10 mm is stored in advance.

  In step S22, the arithmetic processing unit 81 monitors the subsequent effective value E and determines whether or not the effective value E is larger than the threshold value B1. If E> B1, the process of step S22 is executed again. On the other hand, if E> B1, the process proceeds to step S23. In step S23, the arithmetic processing unit 81 determines that the rotary shaft 20 has been displaced by a displacement amount M3 corresponding to the threshold value B1, and performs recording and notification as necessary.

  Next, in step S24, the arithmetic processing unit 81 monitors the subsequent effective value E and determines whether or not the effective value E is larger than the threshold value B2. If E> B2, the process of step S24 is executed again. On the other hand, if E> B2, the process proceeds to step S25. In step S25, the arithmetic processing unit 81 determines that the rotary shaft 20 has been displaced by the displacement amount M4 corresponding to the threshold value B2, performs recording and notification as necessary, and ends the process in step S26.

  As described above, the state monitoring apparatus 100 includes the arithmetic processing unit 81 that receives the output of the state monitoring sensor 145 and determines whether or not an abnormality has occurred in the bearing. The arithmetic processing unit 81 (i) determines the threshold value Z (first threshold value) based on the feature quantity obtained from the state monitoring sensor 145 at the initial stage of the preliminary operation period T0 (first operation period). , (Ii) obtained from the state monitoring sensor 145 at the initial stage of the first threshold generation period T1 (second operation period) after the preliminary operation period T0 in which the feature amount is changed to a state smaller than the threshold value Z. Based on the feature value, a threshold value A1 (second threshold value) is determined. (Iii) The feature value obtained from the state monitoring sensor 145 after the first threshold value generation period T1 is greater than the threshold value A1. When the transition from the small state to the large state is made, it is determined that an abnormality has occurred in the bearing 160, and (iv) the second threshold value generation period T2 (the first threshold value) after the feature value transitions to a state greater than the threshold value A1 Condition monitoring at the beginning of 3 operation periods) Based on the feature quantity obtained from the sensor 145, threshold values B1 and B2 (third threshold value) are determined, and (v) predetermined displacement amounts M3 and M3 respectively corresponding to the threshold values B1 and B2. Mvi is stored, and (vi) when the feature quantity obtained from the state monitoring sensor 145 after the second threshold value generation period T2 transitions from a state smaller than the threshold values B1 and B2 to a larger state, the rotary shaft 20 Are determined to be displaced by M3 and M4, respectively (FIGS. 12 to 14).

  By determining the threshold values B1 and B2 in this way, the amount of displacement of the rotating shaft 20 from the start of operation (the amount of change in the gap between the inner ring and the outer ring due to bearing wear) has reached M3 (for example, 0.60 mm). Or that M4 (for example, 0.10 mm) has been reached.

  In the preliminary operation period T0, the friction member 146 is worn to the limit as long as it does not come into contact with the rotary shaft 20, so that a phenomenon in which wear rapidly increases after about 2 hours (hours) from the start of operation. It can be caught immediately with little time delay.

[Modification of Embodiment 2]
In the modification of the second embodiment, an example will be described in which the same processing as the detection processing of the second embodiment is performed on the sliding bearing instead of the rolling bearing. Since the configuration of the slide bearing and the state monitoring device is shown in FIG. 9, the description thereof will not be repeated here.

  FIG. 15 is a diagram illustrating measurement data of the state monitoring device according to the modification of the second embodiment. The data in FIG. 15 is obtained under the same measurement conditions as the data in FIG.

  FIG. 15 shows a displacement X4, an effective value E4, and a variation coefficient C4. The displacement X4 indicates a displacement in which the bearing load direction of the rotating shaft 20 is positive. The effective value E4 is a square root of an average value of values obtained by squaring each sampling value of the output of the state monitoring sensor 145 included in the data length of 15 seconds. The variation coefficient C4 is obtained by dividing the standard deviation of the sampling value by the arithmetic average and represents a relative variation.

  The plot of the effective value E4 and the variation coefficient C4 is obtained by plotting values calculated for a data length of 15 seconds at 15-hour intervals, and the displacement X4 of the rotating shaft 20 is near the friction member 146 for comparison. These are instantaneous values measured using other displacement meters.

  In the bearing 160A, wear rapidly increases from about 270 hours (hour) in operation time, and the displacement X4 of the rotary shaft 20 gradually increases. In the modification of the second embodiment, in the preliminary operation period T0, the friction member 146 is worn to the limit as long as it does not come into contact with the rotating shaft 20, so the wear before and after the operation time of 270 hours (hours) increases rapidly. This phenomenon can be captured immediately with little time delay.

  Note that threshold value Z, A1, B1, and B2 calculation processing and abnormality determination processing are the same as the processing of the flowcharts of FIGS. 13 and 14, and therefore description thereof will not be repeated.

In this way, a similar state monitoring device can be realized for the sliding bearing.
Although the embodiment of the present invention has been described above, the above-described embodiment can be variously modified.

  For example, in FIG. 1 and the like, an example in which the present invention is applied to a bearing of a wind power generator is shown, but the state monitoring apparatus of the present embodiment can also be applied to a bearing such as a railway vehicle or a spindle. In particular, the slide bearing is suitably used for a small machine.

  In addition, when there is a possibility that the direction in which the bearing load acts may change or when the bearing load is indefinite, monitoring may be performed by providing a plurality of friction members at different positions.

  Moreover, although the example of the effective value of AE was shown as a feature-value of measurement data, you may use another physical quantity as a feature-value. For example, typical effective values such as AE and vibration acceleration, maximum value, minimum value, kurtosis, skewness, coefficient of variation (standard deviation / average value), standard deviation, variance, peak-to-peak A value etc. can be used.

  Note that the feature amount of the measurement data can be calculated with a data length of at least one rotation of the rotating shaft in order to avoid adverse effects due to rotational runout and surface roughness distribution on the contact surface of the rotating shaft 20 with the friction member 146. preferable. Further, the feature amount may be calculated after the band pass filter processing or may be calculated after being converted into the frequency domain by FFT processing.

  The contact area of the friction member 146 with the rotating shaft 20 may increase continuously as the displacement amount of the rotating shaft 20 increases. In this case, information indicating the correlation between the amount of displacement of the rotating shaft 20 and the feature amount output from the state monitoring sensor 145 is acquired in advance through experiments or the like, and the arithmetic processing device 81 uses the information to obtain a feature. What is necessary is just to determine the displacement amount of the rotating shaft 20 according to quantity.

  Further, the contact area of the friction member 146 with the rotating shaft 20 may continuously increase as the amount of displacement of the rotating shaft 20 increases. In this case, information indicating the correlation between the amount of displacement of the rotating shaft 20 and the feature amount output from the state monitoring sensor 145 is acquired in advance through experiments or the like, and the arithmetic processing device 81 uses the information to obtain a feature. What is necessary is just to determine the displacement amount of the rotating shaft 20 according to quantity.

  Further, the threshold values Z, A, A1, B, B1, and B2 for detecting the bearing abnormality are determined based on the feature amount calculated in the entire threshold generation period, or first, the threshold generation period. The feature amount may be calculated in a plurality of small periods, the value may be calculated again in the entire period, and the value may be determined based on the feature amount. The threshold values Z, A, A1, B, B1, and B2 may be determined in advance by experiments or the like. In this case, steps S1, S2, S6 and S7 in FIG. 8 and steps S11, S12, S15, S16, S20 and S21 in FIGS. 13 and 14 can be omitted.

  Further, in the case of a bearing used in a harsh environment such as ultra-high temperature, ultra-low temperature, liquid, and vacuum atmosphere, in order to protect the state monitoring sensor 145, a long friction member 146 is used, or the friction member 146 and the state monitoring sensor 145 are used. The distance between the bearing and the friction member 146 and the state monitoring sensor 145 may be greatly separated by connecting the two with a long part made of a material that easily transmits vibration acceleration.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and is intended to include meanings equivalent to the scope of claims for patent and all modifications within the scope.

  DESCRIPTION OF SYMBOLS 10 Wind power generator, 20 Rotating shaft, 25 Hub, 30 Blade, 40 Step-up gear, 50 Generator, 52 Control panel, 54 Transmission line, 60, 60A, 60B, 160, 160A Bearing, 80 Data processing device, 81 Calculation Processing device, 90 nacelle, 92 tower, 100, 101 condition monitoring device, 120, 220 housing, 121, 221 bearing holder, 131 inner ring, 132 outer ring, 133 rolling element, 141 stay, 142 vibration isolator cover, 143 vibration isolator 145 State monitoring sensor, 146, 146a-146d Friction member.

Claims (11)

A state monitoring device for detecting an abnormality of a bearing in which a fixed ring is fixed to a housing,
A friction member arranged to face the peripheral surface of the rotating shaft so that the degree of contact changes when the rotating shaft supported by the bearing is displaced with respect to the housing;
A state monitoring sensor in contact with the friction member,
The state monitoring sensor is an AE sensor or an acceleration sensor,
The state monitoring device, wherein the friction member has a shape such that a contact area with the rotation shaft increases in accordance with an increase in a displacement amount of the rotation shaft.   The state monitoring device according to claim 1, wherein a contact area of the friction member with the rotation shaft increases stepwise in accordance with an increase in a displacement amount of the rotation shaft.   The state monitoring device according to claim 1, wherein the friction member is arranged on a side on which a bearing load acting on the bearing acts with respect to the rotating shaft.   The state monitoring device according to claim 3, wherein a cross-sectional area of the friction member perpendicular to the direction of the bearing load increases stepwise as the distance from the rotation shaft increases.   5. The surface of the friction member facing the rotation shaft in a cross-section of the friction member when cut along a plane including the axis of the rotation shaft and parallel to the direction of the bearing load is stepped. The state monitoring device described in 1.   The state monitoring device according to claim 1, further comprising a stay that fixes the friction member and the state monitoring sensor to the housing.   The state monitoring apparatus according to claim 6, further comprising a vibration isolating material that blocks vibrations disposed between the state monitoring sensor and the stay.   2. The state according to claim 1, wherein during friction between the friction member and the rotating shaft, the wear amount of the friction member per one rotation of the rotating shaft is larger than the wear amount of the bearing per one rotation of the rotating shaft. Monitoring device. An arithmetic processing unit that receives the output of the state monitoring sensor and determines whether or not an abnormality has occurred in the bearing;
The arithmetic processing unit includes:
When the characteristic amount obtained from the state monitoring sensor transitions from a state smaller than a first threshold value to a larger state, it is determined that an abnormality has occurred in the bearing,
The state monitoring apparatus according to claim 2, wherein a displacement amount of the rotating shaft is determined based on a comparison result between the feature amount and a second threshold value that is larger than the first threshold value. An arithmetic processing unit that receives the output of the state monitoring sensor and determines whether or not an abnormality has occurred in the bearing;
The arithmetic processing unit includes:
The first threshold value is determined based on the feature amount obtained from the state monitoring sensor in the first operation period, and the feature amount is changed to a state smaller than the first threshold value than the first operation period. Based on the feature amount obtained from the state monitoring sensor in the subsequent second operation period, the second threshold value is determined,
When the characteristic amount obtained from the state monitoring sensor after the second operation period has changed from a state smaller than the second threshold value to a larger state, it is determined that an abnormality has occurred in the bearing,
Based on the feature amount obtained from the state monitoring sensor in the third operation period after the feature amount has transitioned from a state smaller than the second threshold value to a larger state, the feature amount is larger than the second threshold value. 3 Determine the threshold,
Storing a predetermined amount of displacement corresponding to the third threshold value;
When the characteristic amount obtained from the state monitoring sensor after the third operation period transits from a state smaller than the third threshold value to a larger state, the rotation shaft is displaced by the predetermined displacement amount. The state monitoring apparatus according to claim 2, wherein the state monitoring apparatus determines that it has been performed. A state monitoring method for detecting an abnormality of a bearing in which a fixed ring is fixed to a housing by a state monitoring device,
The state monitoring device
A friction member arranged to face the peripheral surface of the rotating shaft so that the degree of contact changes when the rotating shaft supported by the bearing is displaced with respect to the housing;
A state monitoring sensor in contact with the friction member,
The state monitoring sensor is an AE sensor or an acceleration sensor,
The friction member has a shape such that a contact area with the rotation shaft increases in accordance with an increase in a displacement amount of the rotation shaft,
The state monitoring method includes:
Determining that an abnormality has occurred in the bearing when the characteristic amount obtained from the state monitoring sensor transitions from a state smaller than a first threshold value to a larger state;
Determining the amount of displacement of the rotating shaft based on a comparison result between the feature amount and a second threshold value greater than the first threshold value.

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