JPS6023622A - Observing device of thrust bearing - Google Patents

Abstract

PURPOSE:To detect an abnormal point in a thrust bearing so as to prevent the bearing from causing its trouble, by using a fluid film pressure converter, signal pickup means, gap sensor and a rotary position detector and catching a condition in which a stationary plate forms a lubricating fluid film. CONSTITUTION:A fluid film pressure converter 14 is mounted in the vicinity of the slipping surface of a rotary disc 4 and connected to a slip ring 15, being used as a signal pickup means, through a thrust collar 2 and lead wire outgoing grooves 2a, 4a. A gap sensor 12 is provided in the central bottom face of a stationary plate 6, detecting a flection distance deltamm. of coil springs 7. While the fluid pressure converter 14 detects a fluid film pressure P on the slipping surface of the stationary plate 6. Output signals of the gap sensor 12, fluid film pressure converter 14 and a pulse mark detector 17 are input to an abnormality decision device 18, in this way, it is decided whether or not abnormality is existent in the stationary plate 6.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a device for monitoring an abnormality in a thrust bearing in a rotating machine, and in particular, the present invention relates to a device for monitoring abnormalities in a thrust bearing in a rotating machine. The present invention relates to a thrust bearing monitoring device that can detect plate abnormalities at an early stage.

[Technical background of the invention and its problems]

In recent years, the scale of plants in general industries has continued to increase in size, and along with this, rotating machines have also become larger and the number of installed machines has also increased.

Therefore, since high reliability is required for such rotating machines, it is necessary to perform maintenance and inspections to prevent accidents. Easy streak bearing abnormalities have a large effect on other parts, so maintenance must be carried out reliably.

By the way, although thrust bearings are conventionally important elements in the above-mentioned rotating machines, methods for monitoring them are extremely insufficient. In other words, conventional methods for monitoring thrust bearings include measuring the temperature of the stationary plate,
Methods such as measuring the vibration of the shaft system or chemically analyzing the lubricating fluid have been adopted, but these monitoring methods have the disadvantage that they cannot be detected unless the thrust bearing is damaged and the damage progresses considerably. In many cases, by the time an abnormality is detected, it has already developed into a bearing accident.

When this bearing accident occurs, it takes a long time to recover, and during that time the rotating machine is stopped, which reduces its operating rate and becomes a bottleneck in improving productivity. In particular, damage to thrust bearings for water turbine generators and turbines, which are large-capacity machines, results in extremely large losses for rotating machines.

Therefore, when an abnormal condition or initial damage occurs in such a thrust bearing, it is very important to detect it and take necessary measures before it develops into a major bearing accident.

Now, among commonly used high-load thrust bearings, thrust bearings using oil as the lubricating fluid are most commonly used. In this type of bearing, when the rotating machine is operating, an oil film is formed between the stationary plates due to the viscous effect of the oil on the entire surface of the rotating shaft, preventing direct contact between the rotating shaft and the stationary plate. ing.

However, if the base surface is damaged due to poor assembly of the shaft system, overload, foreign matter, cavitation, etc., it becomes difficult to form an oil film between the stationary plate and the rotating shaft. In other words, the oil film becomes extremely thin and eventually breaks, leading to a bearing accident. Before such an oil film breaks, monitoring methods such as the above-mentioned bearing temperature measurement method have a problem in that the responsiveness to changes in the oil film is extremely insensitive. On the other hand, recently, fluid film thickness measurement methods have been studied to monitor the thickness of this oil film, but the oil film is usually extremely thin, ranging from several tens to hundreds of microns, and immediately before a bearing accident, several Since it is on the order of microns, conventional instruments cannot detect it with high precision and are extremely unreliable.

[Purpose of the invention]

The present invention was made to solve the above problems, and its purpose is to provide a thrust bearing monitoring device that can detect abnormalities before the fluid film ruptures and prevent bearing accidents. Our goal is to provide the following.

[Summary of the invention]

In order to achieve the above object, the present invention includes a thrust collar attached to a rotating shaft of a rotating machine, a rotary plate fixed to the thrust collar, and a plurality of thrust collars arranged relative to the rotary plate in the direction of the rotating shaft. a bearing box filled with lubricating fluid and housing the rotating plate and the stationary plate;
In this thrust bearing comprising an elastic body supporting the stationary plate at the bottom of the bearing box, the elastic body is provided near all surfaces of the rotating plate and is formed on all sides of the stationary plate as the rotating shaft rotates. a fluid film pressure transducer for detecting the pressure of the fluid film; a signal extraction means for extracting an output signal of the fluid film pressure transducer to a stationary side; a gap sensor that detects the amount of deflection of the elastic body due to a load; a rotational position detector that detects the rotational position of the rotating shaft by detecting the position of the fluid film pressure transducer; the signal extraction means; and the gap sensor. and an abnormality determination device that determines whether or not there is an abnormality in the stationary plate based on each output signal from the rotational position detector.

[Embodiments of the invention]

An embodiment of the present invention shown in the drawings will be described below. FIG. 1 shows an example of the configuration of a thrust bearing equipped with a monitoring device according to the present invention in a joint cross-sectional view, and in the figure, a thrust bearing for a water turbine generator will be described as an example. In the figure, a cylindrical thrust collar 2 is attached to a rotating shaft 7 of a water turbine generator using a ring key 3. A rotary plate 4 is fixed to the bottom surface of the thrust case 2 by tightening bolts 5.

Further, N fan-shaped stationary plates 6 are arranged radially relative to the rotary plate 4 in the direction of the rotation axis 1, and these stationary plates 6 are equipped with n coil springs 7 as elastic bodies as shown in the figure.
is supported by a spring stand 9 provided at the bottom of the bearing box 8. Each of the above-mentioned elements is housed in a bearing box 8 filled with oil 10 as a lubricating fluid, and on the top surface of this bearing box 8 there are written letters as shown in the figure.
1111 is provided.

On the other hand, a gap sensor 12 is provided at the illustrated position on the bottom surface of the central portion of the stationary plate 6, and its lead wire is taken out to the outside through a lead wire drawer 13 provided in the bearing box 8. I'm here. In addition, the rotating plate 4
Several 01 [body membrane pressure transducer 1] are located near the sliding surface of
4 is cut in several cases, and the lead wires are inserted into the lead wire extraction grooves 2h and 4 formed in the thrust collar 2 and the rotary plate 4.
a to a slip ring 15 as a signal extraction means attached to the end of the rotating shaft 1.

Furthermore, a specific location (1
A rotational pulse mark 16 is pasted on the part), and a pulse mark detector for detecting the rotational position of the rotating shaft 1 by detecting the rotational pulse mark 16 is attached to the second part of the above-mentioned phrase 911 as a rotational position detector. 17 are provided. No here? The pulse mark detector 17 is provided on the same longitudinal section of the stationary plate 6-[, and is configured to emit a pulse when the fluid film pressure transducer 14 passes the reference stationary plate 6-1.

In the above, the cap sensor 12 is for detecting the challenge amount δ of the coil spring 7, and the fluid film pressure transducer 14 is for detecting the fluid film (in this example) formed on the entire surface of the stationary plate 6. This is to detect the oil film) pressure P(k&/cIn2).

Furthermore, the output signal of the gap sensor 12 obtained via the lead wire drawing tube 13, the output signal of the fluid film pressure transducer 14 obtained via the slip ring 15, and the output signal of the nozzle mark detector 17 are determined to be abnormal. vessel 18
is input to determine whether or not there is an abnormality in the stationary plate 6. That is, this abnormality determination device 18 calculates the deflection amount δ, which is the output signal of the cap sensor 12, and the maximum membrane pressure value P max of the fluid film pressure P at each stationary plate 6, which is the output signal of the fluid membrane pressure converter 14. and are subjected to signal processing to obtain the allowable deflection amount δU, respectively.
The presence or absence of an abnormality is determined by comparing the fluid film pressure permissible value Pu with the magnitude relationship.

Here, the sizes of the allowable deflection amount δU and the allowable fluid film pressure value Pu are the actual load W (kg) applied to this thrust bearing.
The settings are changed each time depending on the size of the area.

And, this actual load W is the above-mentioned Sayano sensor, 1
It is determined by integrating the deflection index δ of the coil spring 7, which is the output of No. 2, the spring constant fik (kg/am) of the coil spring 7, and the number n of 70 coil springs. The relationship between the amount of deflection δ of the coil spring 2 and the actual load W is shown in FIG. 2.

Next, the operation of the thrust bearing monitoring device having such a configuration will be described.

When the water turbine generator starts operating, the thrust collar 2 attached to the rotating shaft 1 and the rotating plate 4 fixed thereto rotate.

As a result, a fluid film (oil film) is formed on the entire surface of the stationary plate 6 provided relative to the rotary plate 4 as described above. Then, the pressure P of this fluid film is detected by the fluid film pressure transducer I4, and is inputted to the abnormality determination device 18 via the syslitz ring 15 by a lead wire.

In addition, as the thrust collar 2 rotates, the pulse mark 16 attached to the outer periphery of the upper end also rotates, and this pulse mark 16 is replaced by the pulse mark attached to the fixed side. Each time detected by the detector 17,
The pulse output is then input to the abnormality determiner 18.

Furthermore, as a load W of a certain magnitude is applied to the main thrust bearing as the water turbine generator operates, the coil spring 7 supporting the stationary plate 6 is deflected, and the amount of deflection δ is It is detected by a gap sensor 12 provided on the bottom surface of the center portion of the stationary plate 6, and is inputted to the abnormality determination device 18 via the lead wire inside the lead wire drawer tube 13.

Accordingly, the abnormality determination unit 18 determines whether or not there is an abnormality based on these input signals, the allowable deflection amount δU, and the allowable fluid film pressure value Pu, which are set according to the magnitude of the actual load W. will be carried out. That is, as shown in Figure 3 (1L)
(b) The maximum film pressure value P max on each stationary plate 6 is constant, and as shown in FIG. (C) The fluid film pressure waveform at the center of the stationary plate 6 is equal to the fluid film pressure waveform at the inner and outer periphery. If the state of "larger than normal" is maintained, it is determined to be normal, and if this state is not maintained, it is determined that everything is abnormal.

FIGS. 5 to 7 each show examples of states when an abnormality occurs in the thrust bearing.

First, FIG. 5 shows a state where there is no damage to the stationary plate 6 or misalignment of the shaft system, and an overload load that is more than permissible is simply applied. In this case, the fluid film pressure 2 distribution on each stationary plate 6 is uniform, but the maximum film pressure value P mix and the deflection amount δ of the coil spring 7 are each different from its allowable value Pu
, exceeds δU.

Moreover, FIG. 6 shows a state where misalignment has occurred in the shaft system. In this case, each stationary plate 6
The maximum value P max of the fluid film pressure generated in the rotation period indicates the periodicity of the rotation period, and by checking the waveform of the pulse mark detector 17 of the rotation nozzle 9 and the pulse mark 16, it is possible to understand how to correct the misalignment. can do.

Further, FIG. 7 shows a state in which damage occurs to a part of the outer peripheral side of the bottom surface of the stationary plate 6-1. In this case, it may be impossible to generate a normal waveform of the fluid film on the outer periphery of the stationary plate 6-In, and when the waveform is extremely distorted, it may locally become zero.

As mentioned above, this thrust bearing monitoring device is installed on the rotary plate 4 fixed to the thrust collar 3 attached to the rotary shaft 1 of the water turbine generator, and A fluid film pressure transducer 14 detects the pressure of a fluid film formed on a plurality of stationary plates 6 arranged, and a coil spring 7 provided on the bottom surface of each stationary plate 6 to support the stationary plate 6. The gap sensor 12 detects the amount of deflection δ due to the applied load, and the rotation pulse mark 16 attached at the upper end of the thrust collar 2 and on the same vertical cross-sectional view of the fluid film pressure transducer 14 detects the rotation axis. a pulse mark detector 17 as a rotational position detector that detects the rotational position of the sensor 12 and outputs a pulse; and the gap sensor 12. The static plate 6
and an abnormality determiner 18 that determines whether or not there is an abnormality.

Therefore, an abnormality in the stationary plate 6 can be detected at an early stage before the fluid film is damaged, and the cause and location of the abnormality can be easily determined, thereby preventing the aforementioned bearing accident. It becomes possible to prevent this.

It should be noted that the present invention is not limited to the above embodiments, but can also be implemented as follows.

(,) In the above embodiment, the slip ring 15 is used as a signal extraction means for monitoring the fluid film pressure, but the invention is not limited to this. For example, as shown in FIG. 8, the output signal of the fluid film pressure detector 14 can be The output signal may be input to an FM transmitter 19 mounted on the rotating shaft 1, and the output signal may be received by an FM receiver 20 provided on the front cutter 11 on the fixed side. It is possible to monitor the fluid film pressure even without the shaft end of the shaft 1.

(b) As shown in FIG. 9, gap sensors 12 are provided at three approximately equally spaced locations on the circumference in order to measure the amount of deflection δ of the coil gauge ring 7 that supports the stationary plate 6. According to this, it is possible to more accurately grasp the load sharing on each stationary plate 6, and to monitor misalignment of the shaft system more accurately.

〔Effect of the invention〕

As explained above, according to the present invention, the presence or absence of an abnormality is determined based on the pressure of the fluid film formed on the stationary plate, the rotational position of the rotating shaft, and the amount of deflection of the coil spring. We can provide an extremely reliable thrust bearing monitoring device that can detect abnormalities and their causes before they break and prevent bearing accidents.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal cross-sectional view showing one embodiment of the present invention, Fig. 2 is a view showing the relationship between deflection capture of a coil spring and applied load, and Figs. 3 to 7 are for detailed explanation of the present invention. Figure 8
9 and 9 are configuration diagrams showing other embodiments of the present invention.ノ... Rotating shaft, 2... Thrust collar, 3... Ring key, 4... Rotating plate, 5... Delt, 6...
Stationary plate, 7... Coil spring, 8... Bearing box,
9... Spring stand, 10... Oil, 1... Front cutter, 12... Gap sensor, 13... Lead wire drawing tube, 14... Fluid film pressure transducer, 15... ...Slip ring, 16...Rotation pulse mark, 17...
・Pulse mark detector, 18...FM transmitter, 19・
...FM receiver. Applicant's representative Patent attorney Takehiko Suzue Figure 1 99- Figure 2 - Jtmm > Figure 3, Figure 4 □J

Claims (2)

[Claims] (1) A thrust collar attached to the rotating shaft of a rotating machine, a rotating plate fixed to the thrust collar, a plurality of stationary plates arranged relative to the rotating plate in the direction of the rotating axis, and a lubricating fluid. A thrust bearing comprising a bearing box which is filled inside and houses the rotating plate and the stationary plate, and an elastic body supporting the stationary plate at the bottom of the bearing box, the thrust bearing being provided near the entire surface of the rotating plate. A fluid film pressure transducer that detects the pressure of a fluid film formed on the entire surface of the stationary plate as the rotating shaft rotates, and a signal extraction that extracts the output signal of the fluid film pressure transducer to the stationary side. means, a gap sensor provided at the bottom of the stationary plate to detect the amount of deflection of the elastic body due to the load applied to the thrust bearing, and a gap sensor that detects the amount of deflection of the elastic body due to the load applied to the thrust bearing; a rotational position detector for detecting the rotational position of the
The signal extraction means. 1. A streak bearing monitoring device comprising: an abnormality determiner that determines whether or not there is an abnormality in the stationary plate based on output signals from a gap sensor and a rotational position detector. (2) Slip ring or FM as signal extraction means
A thrust bearing monitoring device according to claim 1, which uses a transmitter and an FM receiver.