JP2018159621A - 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. Preferably, the friction member 146 is disposed on a side on which a bearing load applied to the bearing acts, relative to 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 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.

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

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

  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.

  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 (i) a first threshold value based on the feature value obtained from the state monitoring sensor in the first operation period, and (ii) transitions to a state where the feature value is 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 first operation period, and (iii) obtained from the state monitoring sensor after the second operation period. It is determined that an abnormality has occurred in the bearing when the obtained feature value transitions from a state smaller than the second threshold value to a larger state.

  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 state monitoring method includes: (i) a step of determining a first threshold value based on a feature amount obtained from the state monitoring sensor during the first operation period; and (ii) a state in which the feature amount is smaller than the first threshold value. A step of determining a second threshold value based on a feature quantity obtained from the state monitoring sensor in a second operation period after the first operation period transitioned to (iii) a state after the second operation period And determining that an abnormality has occurred in the bearing when the feature amount obtained from the monitoring sensor transitions from a state smaller than the second threshold value to a larger state.

  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 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 the measurement data of the state monitoring apparatus of Embodiment 2. FIG. 10 is a flowchart for explaining abnormality determination processing executed by the arithmetic processing device 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 FIG. 2 and FIG. 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 60 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 opposite direction 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, since the direction in which the bearing load acts is almost determined once the place where the bearing is used is determined, 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 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 A to a larger state (FIGS. 4, 5, and 5). (See FIG. 7). 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 such wear occurs, 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 diagram illustrating measurement data of the state monitoring apparatus according to the first embodiment. The data in FIG. 4 simulates the case where the direction of the bearing load is vertically downward like the bearing 60A in FIG. 2, and is obtained under the following measurement conditions.
<Measurement conditions>
Apparatus configuration: Configuration shown in FIG. 3 Friction member material: Carbon material state detection sensor: AE (envelope processed time waveform 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 Embodiment 1, the friction member 146 was not brought into contact with the rotating shaft 20 at the start of operation, and the relative distance 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. In FIG. 4, the displacement X1, the effective value E1, and the variation coefficient C1 are shown. 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 a plot of values calculated at a data length of 15 seconds at 10-minute intervals, and the displacement X1 of the rotating shaft 20 is in the vicinity of the friction member 146. 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. In the first embodiment, the threshold value A is determined based on the effective value E1 obtained in the initial period when the friction member 146 at the beginning of operation is not in contact with 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.

  When the friction member 146 is brought close to the rotating shaft 20 without being brought into contact, the distance between the friction member 146 and the rotating shaft 20 can be accurately grasped during installation so that it can be regarded as abnormal if the friction member 146 and the rotating shaft 20 come into contact with each other. 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. The friction member 146 immediately after the start of operation is not in contact with the rotating shaft and is not worn. This period without wear is suitable as a period for generating a threshold value 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.

  FIG. 5 is a flowchart for explaining an abnormality determination process executed by the arithmetic processing unit in the first embodiment. 3 to 5, first, in step S <b> 1, the arithmetic processing unit 81 samples the output signal of the state monitoring sensor 145 during the initial operation period 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.

  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, the process of step S3 is executed again. If E> A, the process proceeds to step S4. In step S4, the arithmetic processing unit 81 determines that an abnormality has occurred in the bearing 160, performs recording or notification as necessary, and ends the process in step S5.

  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. In the first embodiment, the displacement of the bearing 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 wear of the bearing) has increased to an initial gap of 0.06 mm or more accurately. Can be 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. 6 is a diagram illustrating a configuration of a state monitoring apparatus according to a modification of the first embodiment. Referring to FIG. 6, state monitoring apparatus 101 includes a friction member 146 and a state monitoring sensor 145 in 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. 7 is a diagram illustrating measurement data of the state monitoring device according to the modification of the first embodiment. The data in FIG. 7 is obtained under the following measurement conditions.
<Measurement conditions>
Device configuration: Configuration 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. 7 shows the displacement X2, the effective value E2, and the variation coefficient C2. The displacement X2 indicates a displacement in which the direction of the bearing load 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, the threshold value A is determined based on the effective value E2 obtained in the initial period when the friction member 146 in the initial stage of operation is not in contact with 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.

  Note that threshold A calculation processing and abnormality determination processing are the same as the processing of the flowchart of FIG. 5, and therefore description thereof will not be repeated.

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. 8 is a diagram illustrating measurement data of the state monitoring apparatus according to the second embodiment. The data in FIG. 8 is obtained under the same measurement conditions as in FIG. However, the second embodiment differs from the first embodiment in that the friction member 146 is brought into contact with the rotating shaft 20 from the beginning of operation.

  As shown in FIG. 8, the operation period includes a preliminary operation period T1 at the beginning of operation, a subsequent threshold generation period T2, and a determination period T3.

  When the friction member 146 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 parts supporting the friction member 146 such as the stay 141. Therefore, in the preliminary operation period T1, the friction member 146 is greatly worn immediately after the start of operation, but the contact force decreases with the wear, so that the progress of wear of the friction member 146 is shifted to the threshold generation period T2. To do. In order to determine the transition to the threshold generation period T2, the threshold A1 is determined based on the sampled feature amount data such as AE and vibration acceleration in the initial stage of the preliminary operation period T1. Then, based on the fact that the feature amount has decreased below the threshold value A1, it is determined that the preliminary operation period T1 has shifted to the threshold value generation period T2.

  The period until this stagnation (preliminary operation period T1) 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 is increased. And the variation is great.

  On the other hand, the period in which the wear is stagnant (threshold generation period T2) is a period for generating the threshold A2 for detecting an abnormality because there is no abnormality in the bearing and the level and fluctuation of AE and vibration acceleration are small. Is suitable.

  In FIG. 8, the displacement of the rotating shaft gradually increases from the operation time of 2 hours (hour). The time when the clearance between the inner ring and the outer ring of the bearing begins to increase by generating a threshold value A2 for detecting anomalies at around 1.5 hours (hours) when the effective value and coefficient of variation are low and stable. Can be detected accurately.

  The state monitoring method used in the second embodiment includes a step (S11 to S14) of determining a threshold generation period T2 based on a characteristic amount (E3) of measurement data at the initial stage of operation, and a threshold generation period T2. And calculating a threshold value A2 for detecting a bearing abnormality (S15, S16), and detecting a bearing abnormality based on the threshold value A2 (S17, S18). It is. Hereinafter, the abnormality determination process executed by the state monitoring method will be described.

  FIG. 9 is a flowchart for explaining an abnormality determination process executed by the arithmetic processing unit in the second embodiment. 3, 8, and 9, 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> 1), Get 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 A1 based on these values. For example, the average value −3σ or 1/10 of the average value 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 bearing wear, and is a period in which the friction member 146 is in contact with the rotating shaft 20 and AE occurs in the friction member 146.

  In step S13, the arithmetic processing unit 81 determines whether or not the feature amount E obtained from the state monitoring sensor 145 is smaller than the threshold value A1. As long as E <A1 is not satisfied (NO in S13), the preliminary operation period T1 in FIG. 8 has not ended, and the threshold value generation period T2 for determining the threshold value A2 has not transitioned. The process of S13 is executed again.

  If E <A1 is established in step S13 (YES in S13), the arithmetic processing unit 81 determines whether or not the feature value change ΔE is smaller than the determination value B1 in step S14. In FIG. 8, it is preferable that the threshold value A2 is generated after the value of E3 has settled down.

  While ΔE <B1 is not satisfied (NO in S14), the process returns to step S13 again. On the other hand, if ΔE <B1 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 threshold generation period T2 and obtains data for generating the threshold A2. In step S16, the arithmetic processing unit 81 calculates an average value, standard deviation σ, and the like of the data obtained during the threshold generation period T2, and determines the threshold A2 based on these. For example, the average value + 3σ can be set as the threshold value A2. The threshold generation period T2 starts after E <A1 and ΔE <B1 are 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 A2. If E> A2, the process of step S17 is executed again. If E> A2, the process proceeds to step S18. In step S18, the arithmetic processing unit 81 determines that an abnormality has occurred in the bearing 160, performs recording and notification as necessary, and ends the process in step S19.

  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 determines (i) the first threshold value A1 based on the feature value obtained from the state monitoring sensor 145 at the initial stage of the preliminary operation period T1 (first operation period), and (ii) the feature value. Is based on the characteristic amount obtained from the state monitoring sensor 145 in the initial stage of the threshold generation period T2 (second operation period) after the preliminary operation period T1 in which the state transitions to a state smaller than the first threshold value A1. A second threshold value A2 is determined, and (iii) after the threshold value generation period T2, the feature quantity obtained from the state monitoring sensor 145 changes from a state smaller than the second threshold value A2 to a larger state. It is determined that an abnormality has occurred in the bearing 160 (FIGS. 8 to 10).

  According to the state monitoring apparatus of the second embodiment, since the friction member 146 is worn to the limit as long as it does not contact the rotating shaft 20 during the preliminary operation period, the elapsed time from the start of operation is 2 hours (hour ) The phenomenon of rapid increase in front and rear wear can be detected 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. 6, description thereof will not be repeated here.

  FIG. 10 is a diagram illustrating measurement data of the state monitoring device according to the modification of the second embodiment. The data in FIG. 10 is obtained under the same measurement conditions as the data in FIG.

  FIG. 10 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 T1, the friction member 146 is worn to the limit as long as it does not come into contact with the rotary 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 A2 calculation processing and abnormality determination processing are the same as the processing of the flowchart of FIG. 9, and thus 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.

  Furthermore, the threshold value for detecting a bearing abnormality is determined based on the feature value calculated over the entire threshold value generation period, or the threshold value generation period is first divided into a plurality of feature values. May be calculated again, and the feature value may be calculated again over the entire period, and determined based on the feature value.

  In the case of a bearing used in a harsh environment such as ultra-high temperature, ultra-low temperature, liquid, or vacuum atmosphere, in order to protect the sensor, a long friction member 146 is used, or AE or vibration is generated between the friction member 146 and the sensor. The distance between the bearing or the friction member 146 and the sensor may be greatly separated by connecting with a long component made of a material that easily transmits 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 Friction member.

Claims (8)

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 a state monitoring device which is an AE sensor or an acceleration sensor.   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 1, further comprising a stay that fixes the friction member and the state monitoring sensor to the housing.   The state monitoring device according to claim 3, further comprising a vibration isolating material that blocks vibration disposed between the state monitoring sensor and the stay.   The amount of wear of the friction member per rotation of the rotating shaft during friction between the friction member and the rotating shaft is larger than the amount of wear of the bearing per rotation of the rotating shaft. State monitoring device.   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 is further provided, wherein the arithmetic processing unit has a feature value obtained from the state monitoring sensor as a first threshold value. The state monitoring device according to any one of claims 1 to 5, wherein when the transition is made from a smaller state to a larger state, it is determined that an abnormality has occurred in the bearing. 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,
2. It is determined that an abnormality has occurred in the bearing when the characteristic amount obtained from the state monitoring sensor transitions from a state smaller than the second threshold value to a larger state after the second operation period. The state monitoring apparatus of any one of -5. 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 state monitoring method includes:
Determining a first threshold value based on a feature amount obtained from the state monitoring sensor in a first operation period;
Based on the feature value obtained from the state monitoring sensor in the second operation period after the first operation period in which the feature value has transitioned to a state smaller than the first threshold value, the second threshold value is set. A step to determine;
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 the second threshold value to a larger state after the second operation period. , Status monitoring method.

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