CN106643906B - Monitoring method and monitoring system for variable-pitch bearing - Google Patents
Monitoring method and monitoring system for variable-pitch bearing Download PDFInfo
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- CN106643906B CN106643906B CN201611260550.2A CN201611260550A CN106643906B CN 106643906 B CN106643906 B CN 106643906B CN 201611260550 A CN201611260550 A CN 201611260550A CN 106643906 B CN106643906 B CN 106643906B
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- 238000012544 monitoring process Methods 0.000 title claims abstract description 80
- 238000000034 method Methods 0.000 title claims abstract description 37
- 239000000835 fiber Substances 0.000 claims abstract description 98
- 238000005259 measurement Methods 0.000 claims abstract description 21
- 230000003287 optical effect Effects 0.000 claims description 24
- 238000012937 correction Methods 0.000 claims description 3
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- 230000004927 fusion Effects 0.000 description 3
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- 238000003466 welding Methods 0.000 description 3
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- 238000005260 corrosion Methods 0.000 description 2
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- 238000009413 insulation Methods 0.000 description 2
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D21/00—Measuring or testing not otherwise provided for
- G01D21/02—Measuring two or more variables by means not covered by a single other subclass
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K11/00—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00
- G01K11/32—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00 using changes in transmittance, scattering or luminescence in optical fibres
- G01K11/3206—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00 using changes in transmittance, scattering or luminescence in optical fibres at discrete locations in the fibre, e.g. using Bragg scattering
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L1/00—Measuring force or stress, in general
- G01L1/24—Measuring force or stress, in general by measuring variations of optical properties of material when it is stressed, e.g. by photoelastic stress analysis using infrared, visible light, ultraviolet
- G01L1/242—Measuring force or stress, in general by measuring variations of optical properties of material when it is stressed, e.g. by photoelastic stress analysis using infrared, visible light, ultraviolet the material being an optical fibre
- G01L1/246—Measuring force or stress, in general by measuring variations of optical properties of material when it is stressed, e.g. by photoelastic stress analysis using infrared, visible light, ultraviolet the material being an optical fibre using integrated gratings, e.g. Bragg gratings
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Abstract
The invention relates to a monitoring method and a monitoring system for a variable-pitch bearing. Pitch bearing (100) comprises a bearing end face (130, 140) and bolt holes (1-54) formed in the bearing end face (130, 140), and is characterized in that the monitoring method comprises the following steps: monitoring temperature parameters and strain parameters of the bearing end surfaces (130, 140) or the bolt holes (1-54) by using a fiber bragg grating sensing measurement system (500); and correcting the strain parameters of the bearing end surfaces (130, 140) or the bolt holes (1-54) by using the temperature parameters to obtain actual strain parameters.
Description
Technical Field
The invention relates to the technical field of bearing monitoring, in particular to a monitoring method and a monitoring system for a variable pitch bearing.
Background
Energy is the main material basis of social economy and human life, and is the power of social development. However, the reserves of non-renewable energy sources such as petroleum, coal, natural gas, etc., which are major pillars of world energy, are decreasing, wind power generation is being developed in various countries of the world, and wind power generation has become a mature scale as a new energy source.
The wind driven generator is equipment for converting wind energy into electric energy, and in the wind driven generator, a variable pitch bearing is used as a connecting component of a blade and a hub, so that the variable pitch bearing plays an important role in the variable pitch process of wind power generation. The variable pitch is realized by adjusting the angle of the blade and changing the attack angle of the airflow to the blade, so that the aerodynamic force obtained by the wind turbine generator is changed, and the wind turbine generator outputs the designed output power. Due to the weight of the blade and the large aerodynamic thrust, the pitch bearing is subjected to a large load, and particularly, the end face of the pitch bearing and the bolt hole for connection may be cracked due to the large load. Moreover, the working environment of the variable pitch bearing is severe, the temperature gradient of the environment is large, and the variable pitch bearing is also likely to fail due to the fact that the temperature change affects the lubrication of grease and the characteristics of materials. Due to the fact that the structure stress of the variable-pitch bearing is complex, the working temperature field is distributed unevenly, and monitoring means are very important in order to early warn, reduce quality and safety accidents.
Disclosure of Invention
In the past, the technical means for monitoring the bearing is insufficient, and the stress characteristic of the bearing cannot be comprehensively considered. The current means is to utilize resistance strain gauge to carry out installation measurement at possible atress concentration point, but because the regional installation space of bearing stress concentration itself and surveyed the face less, in addition resistance strain gauge measurement is single point stress measurement, if will describe line stress and face stress and need install a large amount of resistance strain gauges, lead wire and collection equipment passageway, the cost is higher, the operation is difficult, life is short, it has great influence to the monitoring result to add the oar bearing operational environment. In addition, if the temperature field distribution of the whole bearing needs to be measured, a temperature sensor, a wiring device and a collecting device need to be additionally arranged.
The invention aims to provide a monitoring method and a monitoring system for a variable pitch bearing, which can avoid electromagnetic interference, prolong the service life, are simple to install and wire and can reduce the monitoring cost of the variable pitch bearing.
One aspect of the present invention provides a monitoring method for a pitch bearing, where the pitch bearing includes a bearing end surface and a bolt hole formed in the bearing end surface, the monitoring method including: monitoring the temperature parameter and the strain parameter of the bearing end surface or the bolt hole by using a fiber bragg grating sensing and measuring system; and correcting the strain parameter of the bearing end face or the bolt hole by using the temperature parameter to obtain an actual strain parameter.
Another aspect of the present invention provides a monitoring system for a pitch bearing, the pitch bearing including a bearing end surface and a bolt hole formed in the bearing end surface, the monitoring system including: the fiber grating sensing measurement system is used for monitoring the temperature parameter and the strain parameter of the bearing end surface or the bolt hole; and the correcting unit is used for correcting the strain parameter of the bearing end surface or the bolt hole by using the temperature parameter so as to obtain an actual strain parameter.
According to the monitoring method and the monitoring system of the variable-pitch bearing, the conventional resistance strain gauge is replaced by the fiber bragg grating sensing and measuring system. Because the variable-pitch bearing is sometimes in a high-humidity, smog or thunder working environment, the fiber grating sensor is made of optical fibers, the optical fibers are good in insulation performance, corrosion-resistant and stable in chemical performance, and do not need to be driven by a power supply, optical signals transmitted in the fiber grating sensor are not influenced by electromagnetic interference, and the fiber grating sensor can be stably used in the high-humidity, smog, thunder or electromagnetic interference working environment. Therefore, electromagnetic interference can be avoided, the service life is prolonged, and the installation and wiring are simple. In addition, the fiber grating sensor can form shapes corresponding to selected positions such as the end surface of the outer ring of the variable-pitch bearing, the end surface of the inner ring, the circumferential surface of the outer ring or bolt holes through modes such as bare grating coverage, micro sensor fusion welding and the like, so that the installation difficulty and the installation cost are low.
According to the monitoring method and the monitoring system of the variable-pitch bearing, the strain and the temperature of the end surface of the bearing are monitored by using the fiber bragg grating sensing and measuring system, and the strain of the bolt hole is obtained according to the strain of the end surface of the bearing and the pre-established corresponding relation between the strain of the end surface of the bearing and the strain of the bolt hole. The strain of the bolt hole of the pitch bearing can be obtained only by installing the fiber bragg grating sensor on the bearing end face of the pitch bearing according to the preset corresponding relation between the strain of the bearing end face of the pitch bearing and the strain of the bolt hole of the pitch bearing, and the fiber bragg grating sensor does not need to be installed in both the bearing end face and the bolt hole of the pitch bearing, so that the monitoring cost of the bearing end face and the bolt hole of the pitch bearing is reduced. In addition, according to the strain of the bearing end face of the variable pitch bearing and the corresponding relation between the preset strain of the bearing end face of the variable pitch bearing and the strain of the bolt hole of the variable pitch bearing, the strain of the bolt hole can be accurately obtained, a sensor does not need to be installed in the bolt hole, bolts can be placed in the bolt hole, and the service life of the variable pitch bearing is guaranteed. Therefore, the service life of the variable pitch bearing can be ensured, and meanwhile, a more accurate monitoring result of the strain in the bolt hole can be obtained. Or monitoring the strain and the temperature of the bolt hole by using a fiber bragg grating sensing and measuring system, and acquiring the strain of the bearing end face according to the strain of the bolt hole and the pre-established corresponding relation between the strain of the bearing end face and the strain of the bolt hole. Namely, similarly, the strain of the end face and the bolt hole of the pitch bearing can be obtained only by installing the fiber bragg grating sensor in the bolt hole of the pitch bearing according to the corresponding relation between the preset strain of the bearing end face of the pitch bearing and the strain of the bolt hole of the pitch bearing, and the fiber bragg grating sensor does not need to be installed in both the bearing end face and the bolt hole of the pitch bearing, so that the monitoring cost of the bearing end face and the bolt hole of the pitch bearing is reduced.
According to the monitoring method and the monitoring system of the variable pitch bearing, the fiber grating sensors are arranged at 0 degree, 90 degrees, 180 degrees and 270 degrees of the circumference of the end surface of the bearing, namely the fiber grating sensors are arranged in an annular arrangement mode. Through the arrangement of the fiber bragg grating sensors, the line or surface stress and the temperature field of the variable pitch bearing can be accurately evaluated, the design parameters are optimized, and the fault probability is reduced.
According to the monitoring method and the monitoring system of the variable pitch bearing, a plurality of measuring points are arranged at 0-degree and 180-degree positions of the circumference of the end face of the bearing to install the fiber bragg grating sensor. Because the loads borne at the positions of 0 degree and 180 degrees on the bearing end surface of the variable pitch bearing are large, multi-point measurement is concentrated at the position, and therefore the stress state at the position can be measured more accurately.
According to the monitoring method and the monitoring system of the variable-pitch bearing, the fiber bragg grating sensor is installed on the inner wall of the bolt hole along the axial direction or the radial direction. Because the inner wall cracks of the bolt holes of the variable pitch bearing are easy to damage along the axial direction or the radial direction, the fiber bragg grating sensors are arranged along the axial direction or the radial direction, and therefore the stress state of the bolt holes can be measured more accurately.
According to the monitoring method and the monitoring system of the variable-pitch bearing, the fiber bragg grating sensor is connected with the optical demodulator through the fiber optic link, and two ends of the fiber optic link are respectively connected with the optical demodulator. Therefore, data can be synchronously acquired, a communication fault redundancy design can be realized, and even if a fault occurs at a certain position in the middle of the optical path, the communication test of the whole optical path cannot be influenced.
Drawings
Features, advantages and technical effects of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings.
FIG. 1 is a front view showing the structure of a pitch bearing to which the present invention relates;
fig. 2 is a configuration diagram showing a fiber grating sensing measurement system according to the present invention;
FIG. 3 is a flow chart illustrating one of the monitoring methods of the pitch bearing to which the present invention relates;
FIG. 4 is a flow chart illustrating a second method of monitoring a pitch bearing according to the present invention;
FIG. 5 illustrates the corresponding relationship of the strain of the outer ring end face of the pitch bearing and the strain of the bolt hole;
fig. 6 is a configuration diagram showing a monitoring system for a pitch bearing according to the present invention.
In the drawings, like parts are provided with like reference numerals. The figures are not drawn to scale.
Description of the reference symbols
100 variable pitch bearings; 110 bearing outer races; 120 bearing inner race; 130 outer ring end face; 140 inner ring end faces; 1-54 bolt holes; 200 fiber grating strain and temperature sensors; 300 optical fiber links; a 400 light demodulator; 500 fiber grating sensing measurement system; 500a correction unit; 600 an acquisition unit; 700 early warning unit; 800 monitoring system
Detailed Description
The embodiments of the present invention will be described in further detail with reference to the drawings and examples. The following detailed description of the embodiments and the accompanying drawings are provided to illustrate the principles of the invention and are not intended to limit the scope of the invention, i.e., the invention is not limited to the described embodiments.
In the description of the present invention, it is to be noted that, unless otherwise specified, "a plurality" means one or more than one; "plurality" means two or more; the terms "upper", "lower", "left", "right", "inner", "outer", "front", "rear", "head", "tail", and the like, indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are only for convenience in describing and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed in a particular orientation, and be operated, and thus, should not be construed as limiting the invention.
The variable pitch bearing is an important component in a variable pitch system of the wind driven generator as a connecting component of a blade and a hub, and the structural form of the variable pitch bearing is divided into an inner tooth type and an outer tooth type. The inner tooth type means that teeth of an inner ring of the bearing are meshed with a pinion of a driving motor, and the inner ring is connected with the blades through bolts, and the outer ring is connected with the hub through bolts; the external tooth type means that the teeth of the outer ring of the bearing are meshed with the pinion of the driving motor, the connection mode is that the outer ring is connected with the blades through bolts, and the inner ring is connected with the hub through bolts. In the following, the present embodiment will be described by taking an external-tooth-type pitch bearing as an example.
Fig. 1 is a front view showing the structure of a pitch bearing according to the present invention. As shown in fig. 1, the pitch bearing 100 includes a bearing outer ring 110, a bearing inner ring 120, and bolt holes for connecting the blade and the hub, which are opened on an outer ring end surface 130 and an inner ring end surface 140, and 54 bolt holes are illustrated in fig. 1 and are respectively labeled with numbers 1, 2, and 3 … 54 in the clockwise direction. The bearing outer race 110 is connected to a blade (not shown) by bolts, and the bearing inner race 120 is connected to a hub (not shown) by bolts. The bearing outer race 110 is able to rotate relative to the bearing inner race 120, thereby changing the angle of the blade facing the wind and maintaining the blade in an optimal windward state. The internal structure form of the variable pitch bearing comprises a double-row ball bearing and the like, and the variable pitch bearing not only can bear radial load, but also has certain bearing capacity for axial load.
As described above, in the wind power generator, the pitch bearing plays an important role in the pitch process of wind power generation. The variable pitch is realized by adjusting the angle of the blade and changing the attack angle of the airflow to the blade, so that the aerodynamic force obtained by the wind turbine generator is changed, and the wind turbine generator outputs the designed output power. Due to the weight of the blade and the large aerodynamic thrust, the pitch bearing is subjected to a large load, and particularly, the end face of the pitch bearing and the bolt hole for connection may be cracked due to the large load. Moreover, the working environment of the variable pitch bearing is severe, the temperature gradient of the environment is large, and the variable pitch bearing is also likely to fail due to the fact that the temperature change affects the lubrication of grease and the characteristics of materials. Due to the fact that the structure stress of the variable-pitch bearing is complex, the working temperature field is distributed unevenly, and monitoring means are very important in order to early warn, reduce quality and safety accidents.
Therefore, the inventor of the invention has studied a monitoring means, and fiber bragg grating sensors are respectively installed in the end face of the outer ring of the variable-pitch bearing, the end face of the inner ring of the variable-pitch bearing, the circumferential face of the outer ring of the bearing or bolt holes of the variable-pitch bearing to replace the conventional resistance strain gauge to monitor the strain, temperature parameters and the like of the end face of the outer ring of the variable-pitch bearing, the end face of the inner ring of the variable-pitch bearing, the circumferential face of the outer ring of the bearing or bolt holes of the variable-pitch bearing, and the early warning is carried out according to the strain parameters of the end face of the. That is, the monitoring object of the present invention is the end face and the end face of the outer ring of the pitch bearing, the circumferential face of the outer ring of the bearing, and the inner hole walls of the bolt holes of the connecting bolts, thereby covering each region of the bearing. Because the bearing end surface of the variable pitch bearing and the strain parameter of the bolt hole have a certain relation, the corresponding relation between the strain parameter of the bearing end surface of the variable pitch bearing and the strain parameter of the bolt hole can be pre-established, and the detailed condition is described later.
As shown in fig. 1, a fiber bragg grating strain and temperature sensor 200 is disposed on the outer ring end face 130 of the pitch bearing 100, and the fiber bragg grating strain and temperature sensor 200 collects optical signals, such as strain and temperature parameters, of the outer ring end face 130 of the pitch bearing 100. Specifically, a fiber bragg grating strain and temperature sensor 200 is arranged at each of 0 °, 90 °, 180 ° and 270 ° on the outer ring end face 130 of the pitch bearing 100, and is used for acquiring optical signals of strain and temperature of the outer ring end face 130 of the pitch bearing 100. In fig. 1, 0 ° of the outer ring end surface 130 is the trailing edge position of the blade, and 180 ° of the outer ring end surface 130 is the leading edge position of the blade, depending on the shape of the blade. Further, because the loads borne at 0 ° and 180 ° on the outer ring end face 130 of the pitch bearing 100 are large, multiple measurement points can be arranged at 0 ° and 180 ° on the outer ring end face 130 of the pitch bearing 100 to collectively mount the fiber grating strain and temperature sensor 200, for example, 6 measurement points are arranged at 0 ° to mount the fiber grating strain and temperature sensor 200. The fiber grating strain and temperature sensor 200 is formed into a shape corresponding to a selected part such as the end face of the outer ring of the pitch bearing by means of bare grating coverage, micro sensor fusion welding and the like.
Fig. 2 is a block diagram showing a fiber grating sensor measurement system 500 according to the present invention. As shown in fig. 2, the fiber grating strain and temperature sensor 200 is connected to the optical demodulator 400 through the fiber link 300, and both ends of the fiber link 300 are respectively connected to the optical demodulator 400. The optical demodulator 400 analyzes the optical signals collected by the fiber bragg grating strain and temperature sensor 200, and measures the strain and temperature of the outer ring end face 130 of the pitch bearing 100. The fiber grating strain and temperature sensor 200, the fiber link 300, and the optical demodulator 400 comprise a fiber grating sensing measurement system 500.
Because the test result of the fiber grating strain sensor is greatly influenced by temperature, temperature compensation is needed.
The strain and temperature compensation calculation method is as follows.
Taking one fiber grating strain sensor as an example, the strain of the fiber grating strain sensor is calculated, and the initial center wavelength of the sensor is as follows: λ 0(nm) (measured at room temperature, in the sensor free state);
wavelength calibration after pre-installation on outer ring end face 130: lambda S0 (unit nm, measured at 25 deg.C), the central wavelength of the sensor is changed after the sensor is installed on the outer ring end face 130, and the temperature T1 and the wavelength lambda 1 can be measured on site after the sensor is installed, and then the expression is carried out
λS0＝λ1-(T1-25)*CSSo as to obtain the compound with the characteristics of,
read wavelength at actual measurement after strain generation: lambda [ alpha ]S1(nm) (measurement at room temperature)
Wavelength change: λ ═ λs1-λs0
Fiber grating strain sensorSensitivity change: fS(με/pm)
Temperature coefficient of fiber grating strain sensor: cS(℃/pm)
The strain (mu epsilon) generated during working is calculated by the formula:
Δε＝(Δλ-ΔT*CS)*FS
wherein,
the delta T can be measured by a fiber grating temperature sensor, and the calculation expression is as follows:
ΔT＝(λT1-λT0)/CT
reading wavelength when the fiber grating temperature sensor actually measures: lambda [ alpha ]T1(nm)
Initial wavelength of the fiber grating temperature sensor: lambda [ alpha ]T0(nm, measurement at room temperature)
Sensitivity coefficient of the fiber grating temperature sensor: cT
The stress calculation method comprises the following steps:
the computational expression of stress σ is:
σ＝Δε*E
and △ epsilon is the strain variation, and E is the elastic modulus of the material of the outer ring of the pitch bearing.
Similarly, the stress measured by other fiber bragg grating strain sensors can be obtained by the method. Through the temperature compensation, the actual stress state of the outer ring end face 130 of the pitch bearing can be obtained.
As described above, since there is a certain relationship between the bearing end surface of the pitch bearing and the strain parameter of the bolt hole, the corresponding relationship between the strain parameter of the bearing end surface of the pitch bearing and the strain parameter of the bolt hole can be established in advance. Here, the strain parameter and the bolt of the outer ring end face of the pitch bearing can be obtained in advance according to experimentsThe strain parameter of the hole. Fig. 5 illustrates the corresponding relation of the strain of the outer ring end surface of the pitch bearing and the strain of the bolt hole. Wherein, the X-axis represents the strain of the outer ring end face 130 of the variable pitch bearing 100, the Y-axis represents the strain of the bolt hole, and R2Is a correlation coefficient, and a closer value to 1 indicates a higher correlation between the two. Here, since one measuring point is provided at each of 0 °, 90 °, 180 °, and 270 ° on the outer ring end surface 130 of the pitch bearing 100, the bolt holes corresponding thereto are numbered 1, 14, 28, and 41.
Next, a monitoring method of a pitch bearing according to the present invention will be described in detail. FIG. 3 is a flow chart illustrating one of the monitoring methods of the pitch bearing according to the present invention. In step 101, a corresponding relationship between the strain of the outer ring end surface 130 of the pitch bearing 100 and the strain of the bolt hole is obtained in advance according to experiments. In step 102, the fiber bragg grating strain and temperature sensor 200 is used to collect the temperature and the optical signal of the strain of the outer ring end face 130 of the pitch bearing 100, the optical signal collected by the fiber bragg grating strain and temperature sensor 200 is analyzed by the optical demodulator 400, and the temperature and the strain of the outer ring end face 130 of the pitch bearing 100 are measured. In step 103, the strain of the outer ring end face 130 is corrected using the temperature of the outer ring end face 130 to obtain the actual strain of the outer ring end face 130. In step 104, strain of the bolt holes is obtained according to the actual strain of the outer ring end face 130 and the corresponding relation between the strain of the outer ring end face 130 of the pitch bearing 100 and the strain of the bolt holes. In step 105, the strain of the outer ring end face 130 and the strain of the bolt hole of the pitch bearing 100 obtained in the above manner are compared with a preset fault strain threshold, and an early warning is given according to the comparison result.
In the above monitoring method, the fiber grating sensing and measuring system 500 is used to measure the strain and the temperature of the outer ring end surface 130 of the pitch bearing, and the strain of the bolt hole is obtained according to the measured strain of the outer ring end surface 130 and the corresponding relationship between the strain of the outer ring end surface 130 of the pitch bearing 100 and the strain of the bolt hole, but the monitoring method according to the present invention is not limited thereto, and the fiber grating sensing and measuring system 500 may be used to measure the strain and the temperature of the bolt hole and obtain the strain of the outer ring end surface 130 of the pitch bearing 100 according to the measured strain of the bolt hole and the corresponding relationship between the strain of the outer ring end surface 130 of the pitch bearing 100 and the strain of the bolt hole.
Specifically, a fiber grating strain and temperature sensor 200 is arranged at one measuring point in each of the bolt holes 1, 14, 28 and 41 at 0 °, 90 °, 180 ° and 270 ° of the pitch bearing 100, and the fiber grating strain and temperature sensor 200 is arranged on the inner wall of the bolt hole 1, 14, 28 and 41 along the axial direction or the radial direction. Fig. 4 is a flowchart illustrating a second method of monitoring a pitch bearing according to the present invention. In step 201, a corresponding relation between the strain of the outer ring end surface 130 of the pitch bearing 100 and the strain of the bolt hole is obtained in advance according to experiments. In step 202, optical signals of strain and temperature of the bolt hole of the pitch bearing 130 are collected by using the fiber bragg grating strain and temperature sensor 200, the optical signals collected by the fiber bragg grating strain and temperature sensor 200 are analyzed by the optical demodulator 400, and the strain and temperature of the bolt hole of the pitch bearing are measured. In step 203, the strain of the bolt hole is corrected using the temperature of the bolt hole to obtain the actual strain of the bolt hole. In step 204, the strain of the outer ring end face 130 of the pitch bearing 100 is obtained according to the actual strain of the bolt hole and the corresponding relationship between the strain of the outer ring end face 130 of the pitch bearing 100 and the strain of the bolt hole. In step 205, the strain of the bolt hole of the pitch bearing 100 and the strain of the outer ring end face 130 obtained as above are compared with a preset failure strain threshold, and an early warning is given according to the comparison result.
In the monitoring method of the pitch bearing 100 according to the present embodiment, the conventional resistance strain gauge is replaced with the fiber grating sensing and measuring system 500. Because the variable-pitch bearing is sometimes in a high-humidity, smog or thunder working environment, the fiber grating sensor is made of optical fibers, the optical fibers are good in insulation performance, corrosion-resistant and stable in chemical performance, and do not need to be driven by a power supply, optical signals transmitted in the fiber grating sensor are not influenced by electromagnetic interference, and the fiber grating sensor can be stably used in the high-humidity, smog, thunder or electromagnetic interference working environment. Therefore, electromagnetic interference can be avoided, the service life is prolonged, and the installation and wiring are simple. In addition, the fiber grating sensor can form shapes corresponding to selected positions such as the end surface of the outer ring of the variable-pitch bearing, the end surface of the inner ring, the circumferential surface of the outer ring or bolt holes through modes such as bare grating coverage, micro sensor fusion welding and the like, so that the installation difficulty and the installation cost are low.
In addition, in order to monitor the strain of the bolt hole, a sensor needs to be installed in the bolt hole. In order to ensure that the sensor is not damaged, the bolt can not be placed in the bolt hole for mounting the sensor, but the bolt hole without the bolt is easy to damage due to large load in the operation process of the variable pitch bearing, so that the service life of the variable pitch bearing is shortened. If the strain of the bolt hole is required to be obtained accurately, the sensor needs to be installed in the bolt holes, but the potential safety hazard of fan operation can be brought because the bolts cannot be placed in the bolt holes for installing the sensor. If the unit operation safety is wanted to be guaranteed, the strain of the bolt hole can not be obtained accurately. In view of the above, in the monitoring method of the pitch bearing 100 according to the present embodiment, the fiber bragg grating sensing and measuring system 500 is used to monitor the strain and the temperature of the bearing outer ring end surface 130, and the strain of the bolt hole is obtained according to the strain of the outer ring end surface 130 and the pre-established correspondence between the strain of the outer ring end surface 130 and the strain of the bolt hole. Namely, the strain of the bolt hole of the pitch bearing 100 can be obtained only by installing the fiber bragg grating strain and temperature sensor 200 on the bearing outer ring end face 130 of the pitch bearing 100 and according to the preset corresponding relation between the strain of the bearing outer ring end face 130 of the pitch bearing and the strain of the bolt hole of the pitch bearing, and the fiber bragg grating strain and temperature sensor 200 does not need to be installed in both the bearing outer ring end face 130 and the bolt hole of the pitch bearing 100, so that the monitoring cost of the bearing outer ring end face 130 and the bolt hole of the pitch bearing 100 is reduced. In addition, according to the measured strain of the bearing outer ring end face 130 of the variable pitch bearing 100 and the preset corresponding relation between the strain of the bearing outer ring end face 130 of the variable pitch bearing 100 and the strain of the bolt hole of the variable pitch bearing 100, the strain of the bolt hole can be accurately obtained, so that a sensor does not need to be installed in the bolt hole, the bolt can be placed in the bolt hole, and the service life of the variable pitch bearing 100 is ensured. Therefore, the strain monitoring result in the bolt hole can be obtained more accurately while the service life of the pitch bearing 100 is ensured.
Or, in the monitoring method for the pitch bearing according to the embodiment, the fiber bragg grating sensing and measuring system 500 is used to monitor the strain and the temperature of the bolt hole, and the strain of the bearing outer ring end surface 130 is obtained according to the strain of the bolt hole and the pre-established corresponding relationship between the strain of the bearing outer ring end surface 130 and the strain of the bolt hole. That is, similarly, only the fiber bragg grating strain and temperature sensor 200 needs to be installed in the bolt hole of the pitch bearing 100, and the strain of the outer ring end face 130 of the pitch bearing 100 can be obtained according to the preset corresponding relationship between the strain of the bearing outer ring end face 130 of the pitch bearing 100 and the strain of the bolt hole of the pitch bearing 100, and the fiber bragg grating strain and temperature sensor 200 does not need to be installed in both the bearing outer ring end face 130 and the bolt hole of the pitch bearing 100, so that the monitoring cost of the bearing outer ring end face 130 and the bolt hole of the pitch bearing 100 is reduced.
In addition, in the monitoring method of the pitch bearing 100 according to the present embodiment, the fiber grating strain and temperature sensors 200 are installed at 0 °, 90 °, 180 °, and 270 ° of the circumference of the bearing outer ring end surface 130, that is, the fiber grating strain and temperature sensors 200 are arranged in an annular arrangement manner. Through the arrangement of the fiber bragg grating strain and temperature sensors 200, the line or plane stress and the temperature field of the variable pitch bearing 100 can be accurately evaluated, the design parameters are optimized, and the fault probability is reduced. In addition, the arrangement point of the fiber grating strain and temperature sensor 200 is not limited to this, and the fiber grating strain and temperature sensor 200 may be installed at 0 °, 45 °, 90 °, 135 °, 180 °, 225 °, and 270 ° of the circumference of the bearing outer ring end face 130, so that the line or plane stress and the temperature field of the pitch bearing 100 can be more accurately evaluated.
In addition, in the monitoring method of the pitch bearing 100 according to the embodiment, the fiber bragg grating strain and temperature sensors 200 are arranged at a plurality of measuring points at 0 ° and 180 ° of the circumference of the bearing outer ring end face 130. Because the loads carried at 0 degrees and 180 degrees on the bearing outer ring end surface 130 of the variable pitch bearing 100 are large, multi-point measurement is concentrated at the position, and the stress state at the position can be measured more accurately.
In addition, in the monitoring method of the pitch bearing 100 according to the embodiment, the fiber grating strain and temperature sensor 200 is installed on the inner wall of the bolt hole along the axial direction or the radial direction. Since the inner wall cracks of the bolt hole of the pitch bearing 100 are more easily damaged in the axial direction or the radial direction, the fiber bragg grating strain and temperature sensor 200 is arranged in the axial direction or the radial direction, so that the stress state of the bolt hole can be measured more accurately.
In addition, in the monitoring method of the pitch bearing 100 according to the present embodiment, the fiber grating strain and temperature sensor 200 is connected to the optical demodulator 400 through the fiber link 300, and both ends of the fiber link 300 are respectively connected to the optical demodulator 400. Therefore, data can be synchronously acquired, a communication fault redundancy design can be realized, and even if a fault occurs at a certain position in the middle of the optical path, the communication test of the whole optical path cannot be influenced.
The technical scheme of the invention is realized by a monitoring method of the variable-pitch bearing, but the technical scheme of the invention can also be realized by a monitoring system of the variable-pitch bearing. Fig. 6 is a configuration diagram showing a monitoring system for a pitch bearing according to the present invention. As shown in fig. 6, the monitoring system 800 for a pitch bearing according to the present invention includes: the fiber grating sensing and measuring system 500, the fiber grating sensing and measuring system 500 monitors the temperature parameter and the strain parameter of the bearing end surface or the bolt hole; the correcting unit 500a corrects the strain parameter of the bearing end surface or the bolt hole by using the temperature parameter to obtain an actual strain parameter; an obtaining unit 600, where the obtaining unit 600 pre-establishes a correspondence between a strain parameter of the bearing end surface and a strain parameter of the bolt hole, and obtains the strain parameter of the bolt hole or the strain parameter of the bearing end surface according to an actual strain parameter of the bearing end surface or the actual strain parameter of the bolt hole and the pre-established correspondence between the strain parameter of the bearing end surface and the strain parameter of the bolt hole; and the early warning unit 700 is used for comparing the strain parameter with a preset failure strain parameter threshold value and sending out early warning according to the comparison result. Therefore, the monitoring system 800 adopting the pitch bearing can also obtain the technical effects.
While the invention has been described with reference to a preferred embodiment, various modifications may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In particular, the technical features mentioned in the embodiments can be combined in any way as long as there is no structural conflict. It is intended that the invention not be limited to the particular embodiments disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.
Claims (9)
1. A monitoring method of a pitch bearing (100), the pitch bearing (100) comprising a bearing end face (130, 140) and a bolt hole opened on the bearing end face (130, 140), characterized in that the monitoring method comprises:
pre-establishing a corresponding relation between the strain parameters of the bearing end surfaces (130, 140) and the strain parameters of the bolt holes;
monitoring a temperature parameter of the bearing end face (130, 140) and the strain parameter of the bearing end face (130, 140) with a fiber grating sensing measurement system (500);
-correcting the strain parameter of the bearing end face (130, 140) with the temperature parameter of the bearing end face (130, 140) to obtain an actual strain parameter of the bearing end face (130, 140);
acquiring the actual strain parameter of the bolt hole according to the actual strain parameter of the bearing end surface (130, 140) and the pre-established corresponding relation between the strain parameter of the bearing end surface (130, 140) and the strain parameter of the bolt hole.
2. A monitoring method of a pitch bearing (100), the pitch bearing (100) comprising a bearing end face (130, 140) and a bolt hole opened on the bearing end face (130, 140), characterized in that the monitoring method comprises:
pre-establishing a corresponding relation between the strain parameters of the bearing end surfaces (130, 140) and the strain parameters of the bolt holes;
monitoring the temperature parameter and the strain parameter of the bolt hole by using the fiber bragg grating sensing and measuring system (500);
correcting the strain parameter of the bolt hole by using the temperature parameter of the bolt hole to obtain an actual strain parameter of the bolt hole;
acquiring actual strain parameters of the bearing end surfaces (130, 140) according to the actual strain parameters of the bolt holes and a pre-established corresponding relation between the strain parameters of the bearing end surfaces (130, 140) and the strain parameters of the bolt holes.
3. A monitoring system (800) of a pitch bearing (100), the pitch bearing (100) comprising a bearing end face (130, 140) and a bolt hole opened on the bearing end face (130, 140), characterized in that the monitoring system (800) comprises:
a fiber grating sensing measurement system (500) that monitors temperature and strain parameters of the bearing end faces (130, 140);
a correction unit (500a) for correcting a strain parameter of the bearing end face (130, 140) using the temperature parameter of the bearing end face (130, 140) to obtain an actual strain parameter of the bearing end face (130, 140); and
an obtaining unit (600) configured to establish a correspondence relationship between strain parameters of the bearing end surfaces (130, 140) and strain parameters of the bolt holes in advance, and obtain actual strain parameters of the bolt holes according to the actual strain parameters of the bearing end surfaces (130, 140) and the correspondence relationship between strain parameters of the bearing end surfaces (130, 140) and strain parameters of the bolt holes, which are obtained by the correcting unit (500 a).
4. The monitoring system (800) of claim 3, wherein the fiber grating sensing measurement system (500) is further configured to monitor temperature and strain parameters of the bolt hole;
the correction unit (500a) is further used for correcting the strain parameter of the bolt hole by using the temperature parameter of the bolt hole so as to obtain an actual strain parameter of the bolt hole; and
the obtaining unit (600) is further configured to obtain an actual strain parameter of the bearing end surface (130, 140) from the actual strain parameter of the bolt hole obtained by the correcting unit (500a) and a correspondence relationship between the strain parameter of the bearing end surface (130, 140) and the strain parameter of the bolt hole.
5. The monitoring system (800) according to claim 3 or 4, wherein the fiber grating sensing measurement system (500) comprises a fiber grating sensor (200) collecting optical signals of the temperature parameter and the strain parameter of the bearing end face (130, 140) and the bolt hole, the fiber grating sensor (200) being arranged at 0 °, 90 °, 180 ° and 270 ° of the circumference of the bearing end face, respectively.
6. The monitoring system (800) of claim 5, wherein the fiber grating sensor (200) is further disposed in the bolt holes at 0 °, 90 °, 180 ° and 270 ° of the pitch bearing (100).
7. The monitoring system (800) of claim 5, wherein the fiber grating sensor (200) is provided in plurality at 0 ° and 180 ° of the circumference of the bearing end face.
8. The monitoring system (800) of claim 6, wherein the fiber grating sensor (200) is mounted axially or radially on an inner wall of the bolt hole.
9. The monitoring system (800) according to claim 5, wherein the fiber grating sensor measurement system (500) further comprises a light demodulator (400) for analyzing the light signal collected by the fiber grating sensor (200), the fiber grating sensor (200) is connected to the light demodulator (400) through a fiber link (300), and both ends of the fiber link (300) are respectively connected to the light demodulator (400).
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| CN108896314B (en) * | 2018-09-11 | 2019-12-31 | 河南科技大学 | Detection device for angular contact ball bearing operating state |
| CN109612608B (en) * | 2018-11-29 | 2020-11-17 | 浙江大学 | Installation method of strain bridge for rotating shaft and underwater impeller excitation force measuring platform |
| CN112393902A (en) * | 2019-08-15 | 2021-02-23 | 北京京冶后维风电科技发展有限公司 | Blade bearing detection method of wind generating set |
| CN112525236A (en) * | 2019-09-03 | 2021-03-19 | 舍弗勒技术股份两合公司 | Optical fiber sensor bearing assembly, bearing state monitoring system and measuring method |
| CN110806316B (en) * | 2019-10-11 | 2021-07-13 | 中国人民解放军海军工程大学 | Fiber bragg grating sensing device for detecting stress state of water-lubricated bearing and monitoring system thereof |
| CN110762124B (en) * | 2019-10-30 | 2021-04-09 | 许昌许继风电科技有限公司 | Wind wheel of wind driven generator and variable-pitch bearing thereof |
| CN110848245A (en) * | 2019-11-25 | 2020-02-28 | 山东大学 | Flexible hinge tilting pad bearing and bearing swing angle and fatigue life detection method |
| CN111306011B (en) * | 2020-04-17 | 2020-09-29 | 北京天泽智云科技有限公司 | Method and system for monitoring state of bolt connecting piece of fan blade and variable-pitch bearing |
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| US8792753B2 (en) * | 2011-06-30 | 2014-07-29 | General Electric Company | Method and system for a fiber optic sensor |
| CN103411550B (en) * | 2013-06-28 | 2016-07-06 | 武汉理工大学 | Internal combustion engine main bearing inner surface stress and temperature monitoring method based on fiber grating |
| CN105403337B (en) * | 2015-11-02 | 2018-11-06 | 武汉理工大学 | A kind of fiber grating bolt stress sensor with pre-stretching device |
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