Method for measuring hot charging expansion amount of outer ring of variable pitch bearing of wind driven generator

Abstract

A method for measuring the hot charging expansion amount of a variable pitch bearing outer ring of a wind driven generator comprises the steps that firstly, the bearing outer ring is placed in an assembling area, a heating belt is wound on the outer circle face of the bearing outer ring, and a plurality of metal supports are placed at the positions, close to a radial roller path, in the bearing outer ring; step 2, assembling a dial indicator and a magnetic gauge stand together, then adsorbing the magnetic gauge stand on the metal support, and enabling a measuring head of the dial indicator to be in contact with a radial raceway of the bearing outer ring; 3, the bearing outer ring is heated through the heating belt, and the indicating value of the dial indicator is observed and recorded at regular time in the heating process; and 4, the radial raceway thermal expansion amount delta d of the bearing outer ring is calculated according to the indicating value variable quantity of the dial indicator, delta d is equal to two times of the average value of the multiple indicating value variable quantities, and when delta d meets the process requirement, the heating belt can be powered off, and the bearing is assembled. The problem that an operator gets in and out of the bearing outer ring for multiple times to be scalded is solved, and safe production is guaranteed.

Description

Technical Field

[0001] The invention belongs to the technical field of bearing assembly, and in particular relates to a method for measuring the thermal expansion of an outer ring of a variable pitch bearing of a wind turbine. Background Art

[0002] As the power of wind turbines increases, the load on the pitch bearings also increases. The pitch bearings of large-megawatt wind turbines have changed from the traditional double-row four-point contact ball structure to a three-row roller structure. To ensure that the friction torque of the pitch bearings meets the requirements, the radial raceway of the three-row roller pitch bearings has a negative clearance, and the clearance value is generally less than -0.15mm. When assembling a three-row roller turntable bearing, in order to assemble the radial rollers into the outer ring, the outer ring is generally heated for assembly. In order to ensure the gap between the roller and the outer ring during assembly, it is necessary to measure the expansion of the heated outer ring to ensure that the expansion of the outer ring is greater than the absolute value of the negative clearance.

[0003] The current method for measuring the expansion of hot-loading is to use an inside micrometer or a pipe ruler to measure the radial raceway of the outer ring after heating, subtract the radial raceway size of the outer ring before heating, and calculate the heating expansion of the outer ring. This measurement method has the following limitations: 1. Difficulty in measurement The temperature of the outer ring after heating is about 100℃. The temperature is high, and the inspectors are prone to burns when entering and exiting the outer ring and during the measurement process. The high temperature detection environment is poor and difficult to detect; 2. Unable to obtain the outer ring increase in time When measuring, you need to first use an infrared temperature gun to measure the temperature of the outer ring. After reaching the set temperature, use an inside micrometer or a pipe ruler to measure the radial raceway of the outer ring. Repeated measurements may be required.

[0004] In addition, due to the large size of wind turbine variable pitch bearings, the outer ring diameter is usually more than 3 meters and the weight is more than 1.5 tons. Pit-type tempering furnaces are usually used for heating, but the temperature after heating is high (about 100 degrees), and it is unsafe for people to enter the pit-type furnace for lifting. The tempering furnace is not in the assembly area. After heating, the raceway diameter is measured with an inside micrometer. The lifting and measurement time is long, the ring will lose temperature, making the raceway diameter smaller, and it is difficult to successfully complete the assembly of the bearing. Summary of the invention

[0005] The purpose of the present invention is to provide a method for measuring the thermal expansion of the outer ring of a wind turbine pitch bearing, so as to solve the problems of detection difficulty and potential safety hazards faced in the thermal expansion detection of the outer ring during the thermal installation of the wind turbine pitch bearing.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is: a method for measuring the thermal expansion of the outer ring of a wind turbine pitch bearing, comprising the following steps: Step 1: placing the outer ring of the bearing in the assembly area, wrapping a heating tape around the outer circumferential surface of the outer ring of the bearing, and placing a plurality of metal supports near the radial raceway inside the outer ring of the bearing; Step 2, assemble the dial indicator and the magnetic base together, then align the probe of the dial indicator with the radial raceway of the outer ring of the bearing, adsorb the magnetic base on the metal support, and adjust the position of the dial indicator so that the probe of the dial indicator contacts the radial raceway of the outer ring of the bearing; Step 3, turning on the power of the heating belt to heat the outer ring of the bearing, and regularly observing and recording the indication of the dial indicator during the heating process; Step 4: Calculate the thermal expansion Δd of the radial raceway of the bearing outer ring according to the change in the indicated value of the percentage indicator. Δd is equal to twice the average value of the changes in the indicated values ​​of multiple percentage indicators. When the thermal expansion Δd of the bearing outer ring reaches the process requirements, the heating belt can be powered off and the bearing can be assembled.

[0007] In step one, the outer ring of the bearing is supported on a plurality of supports of equal height.

[0008] In step one, the plurality of metal supports are evenly spaced apart along the circumferential direction.

[0009] In step 2, the measuring range of the dial indicator is not less than 5 mm.

[0010] In step 2, after the probe of the dial indicator contacts the radial raceway of the bearing outer ring, ensure that the dial indicator needle indicates no less than 3 mm, and rotate the dial indicator bezel so that the dial indicator needle indicates the zero position of the dial.

[0011] In step 4, when the number of dial indicators is n, Δd=2×(A1+A2+…+An)÷n, where n is a natural number greater than or equal to 3, and An is the change in the needle indication of the nth dial indicator.

[0012] The beneficial effects of the present invention are as follows: the expansion measurement method of the present invention adopts the mode of heating with a heating belt and real-time monitoring by a dial indicator, thereby avoiding the problem of operators being easily scalded when repeatedly entering and exiting the outer ring of the bearing for measurement, thereby ensuring safe production.

[0013] After the dial indicator of the present invention is fixed at a determined detection position, the change of the expansion amount can be monitored in real time, the measurement process is simple, and there is no need to measure the temperature of the outer ring of the bearing.

[0014] The present invention can heat and measure the expansion of the bearing outer ring in the bearing assembly area. After the expansion meets the assembly process requirements, the bearing can be assembled in situ to avoid temperature loss caused by time-consuming hoisting of the bearing outer ring, thereby ensuring smooth assembly.

[0015] The present invention does not require a complicated measuring device, and the measuring process is simple and rapid, so no professional inspectors are required, and a general operator can complete the detection of the expansion amount. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 This is a front view of the heating and expansion test of the outer ring of the variable pitch bearing of the wind turbine according to the present invention; Figure 2 A top view of the heating and expansion test of the outer ring of the variable pitch bearing of the wind turbine according to the present invention; Markings in the figure: 1. Bearing outer ring, 2. Heating belt, 3. Equal height support, 4. Magnetic base, 5. Dial indicator, 6. Metal support. DETAILED DESCRIPTION

[0018] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments, but they are not intended to limit the invention in any way.

[0019] A method for measuring the thermal expansion of the outer ring of a wind turbine pitch bearing. The wind turbine pitch bearing in this embodiment is a negative clearance three-row roller turntable bearing, and its radial raceway has a negative clearance, which is generally less than -0.15mm. The method comprises the following steps: Step 1: Support the bearing outer ring 1 of the pitch bearing on several equal-height supports 3 in the assembly area, then wrap the heating tape 2 around the outer circumferential surface of the bearing outer ring 1, and place three metal supports 6 inside the bearing outer ring 1 near the radial raceway; Step 2, select a dial gauge 5 with a range of not less than 5mm, assemble it with the magnetic base 4, then align the probe of the dial gauge 5 with the radial raceway of the bearing outer ring 1, adsorb the magnetic base 4 on the metal support 6, and adjust the column and crossbar of the magnetic base 4 so that the probe of the dial gauge 5 contacts the radial raceway of the bearing outer ring 1, and keep the indication of the dial needle not less than 3mm, and then rotate the dial gauge 5 bezel so that the dial gauge 5 needle indicates the zero position of the dial; Step 3, turn on the power of the heating belt 4, set the heating temperature and start heating the outer ring 1 of the bearing. During the heating process, regularly observe and record the needle indication of the dial indicator 5, for example, once every 5-10 minutes; Step 4: Calculate the radial raceway thermal expansion Δd of the bearing outer ring 1, Δd=2×(A1+A2+A3)÷3, where A1, A2, and A3 are the changes in the needle indications of the three dial indicators 5. For this embodiment, since the needle of the dial indicator is pointed at the zero position of the dial in step 2, the needle indication is the change in the needle indication. When the thermal expansion Δd of the bearing outer ring 1 meets the process requirements, the heating belt 2 can be powered off and the bearing can be assembled.

[0020] In this embodiment, the three dial indicators 5 are evenly spaced apart along the circumferential direction.

[0021] The thermal expansion Δd of the negative clearance three-row roller slewing bearing used in this embodiment needs to reach 2mm to meet the assembly requirements, so the average of the indications of the three dial indicators 5 needs to be greater than or equal to 1mm. During the observation process, when the indication of the dial indicator 5 reaches or exceeds 1mm, it is necessary to read and record, and calculate the thermal expansion Δd at this time; when the indications of the three dial indicators 5 are all below 1mm, the average cannot be greater than or equal to 1mm, and it is not necessary to record and calculate at this time.

[0022] In this embodiment, three dial gauges 5 are used for testing, so taking the arithmetic mean of the measurement results can reduce the detection error. In other embodiments, the number of dial gauges 5 can be more than three, which can further reduce the measurement error and improve the measurement accuracy. When the number of dial gauges is n, Δd=2×(A1+A2+…+An)÷n, where n is a natural number greater than or equal to 3.

[0023] The above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the same. Those skilled in the art should understand that the specific implementation modes of the present invention may be modified or replaced by equivalents with reference to the above embodiments. Any modifications or equivalent replacements that do not depart from the spirit and scope of the present invention are within the scope of protection of the pending claims.

Claims

1. A method for measuring the thermal expansion of the outer ring of a wind turbine pitch bearing, characterized in that: The steps include: Step 1: placing the outer ring of the bearing in the assembly area, wrapping a heating tape around the outer circumferential surface of the outer ring of the bearing, and placing a plurality of metal supports near the radial raceway inside the outer ring of the bearing; Step 2, assemble the dial indicator and the magnetic base together, then align the probe of the dial indicator with the radial raceway of the outer ring of the bearing, adsorb the magnetic base on the metal support, and adjust the position of the dial indicator so that the probe of the dial indicator contacts the radial raceway of the outer ring of the bearing; Step 3, turning on the power of the heating belt to heat the outer ring of the bearing, and regularly observing and recording the indication of the dial indicator during the heating process; Step 4: Calculate the thermal expansion Δd of the radial raceway of the bearing outer ring according to the change in the indicated value of the percentage indicator. Δd is equal to twice the average value of the changes in the indicated values ​​of multiple percentage indicators. When the thermal expansion Δd of the bearing outer ring reaches the process requirements, the heating belt can be powered off and the bearing can be assembled.

2. The method for measuring the expansion of thermal installation according to claim 1, characterized in that: In step one, the outer ring of the bearing is supported on a plurality of supports of equal height.

3. The method for measuring thermal expansion according to claim 1, characterized in that: In step one, the plurality of metal supports are evenly spaced apart along the circumferential direction.

4. The method for measuring thermal expansion according to claim 1, characterized in that: In step 2, the measuring range of the dial indicator is not less than 5 mm.

5. The method for measuring thermal expansion according to claim 1, characterized in that: In step 2, after the probe of the dial indicator contacts the radial raceway of the bearing outer ring, ensure that the dial indicator needle indicates no less than 3 mm, and rotate the dial indicator bezel so that the dial indicator needle indicates the zero position of the dial.

6. The method for measuring thermal expansion according to claim 1, characterized in that: In step 4, when the number of dial indicators is n, Δd=2×(A1+A2+…+An)÷n, where n is a natural number greater than or equal to 3, and An is the change in the needle indication of the nth dial indicator.

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