JPS6065908A - Starting of thrust bearing - Google Patents

Abstract

PURPOSE:To improve safety in starting by stopping a high pressure oil pump at least before the rotating speed at the time of starting of a main machine reaches the predetermined rated rotating speed of the main machine, at the time of starting of a thrust bearing, with high peripheral speed and heavy load, of a vertical shaft electric machine etc. CONSTITUTION:In a bearing to the rotary shaft 11 of a main machine such as a vertical shaft electric machine, a thrust bearing 13 installed in an oil bath 12 is composed of a thrust collar 15, a rotary plate 16, a stationary plate 17, a coil spring 18 and a bearing stand 19, and high pressure lubricant discharged from a high pressure oil pump 23 is jetted to the sliding face of the stationary plate 17 through a flow path 21 and a small hole 21a. In a starting of the bearing device, the high pressure oil pump 23 is controlled to be driven before starting of the main machine, and stopped at least before the rotational speed of the main machine at the time of starting reaches 30% of the rated rotational speed of the main machine. By this process, the thickness of oil film on the inner and outer diameter sides of the stationary plate 17 can be retained in the desired thickness or more and safe starting can be obtained.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a method for starting a thrust bearing device, and in particular to a method for starting a thrust bearing device, which is particularly applicable to a spindle rotating electric machine, etc., and is capable of significantly reducing bearing loss during steady operation. The present invention relates to a method for starting a thrust bearing device that can exhibit stable thrust bearing performance when starting a thrust bearing device with a high circumferential speed and a large load.

[Technical background of the invention and its problems]

Thrust bearings, which are generally used in spindle rotating electrical machines, such as vertical water turbine generators and pumped storage generator motors, support not only the weight of the rotating bodies of the generator and water turbine, but also the water thrust of the water turbine or pump turbine. In recent years, with the increase in speed and capacity of generators, the water thrust of some generators has reached three times the rotating weight, and the total thrust load of water thrust and rotating weight exceeds 4000 tons, and the circumferential speed of the thrust bearing has increased. 60m
There are some that exceed / sec. Therefore, in such a large machine, the friction loss of the thrust bearing is I+o-8
kW, which not only affects the efficiency of the entire generator, but also increases the capacity of the thrust bearing cooling system, making it uneconomical.

Thrust bearing devices that can reduce this enormous friction loss and efficiently cool the rotating plate include those that directly water-cool the stationary plate that supports the rotating plate by sliding, those that divide the stationary plate into two in one radius direction, and those that cool the stationary plate upward and downward. Various devices have been invented, such as one with a two-layer structure, but none of them have achieved sufficient results, and recently, alloys for stationary plates have been developed with higher thermal conductivity and elastic modulus than conventional iron-based metals. It was invented to manufacture it from a copper-based metal with a small amount.

In this way, due to its high thermal conductivity, the absolute value of the bearing temperature will be lowered by more than 20°C compared to conventional iron-based metal bearings, and because its elastic modulus is small, the rotating plate will move inside and outside during operation. Even if the stationary plate is deformed into a convex shape due to a temperature difference in the diameter, the stationary plate, including the wedge-shaped oil film, will be deformed into a concave shape, thereby realizing a thrust bearing device with an extremely high load-bearing capacity.

By the way, thrust bearings used in indoor shaft turbine generators or pumped storage generator motors (hereinafter referred to as main engines) have a high-pressure oil pump installed externally installed on the bearing sliding surface to avoid boundary lubrication during startup and shutdown. High-pressure oil is sent to forcibly create an oil film to prevent bearing seizure. Therefore, when starting the main engine from a stopped state, if the thermal deformation in the radial direction of the rotating plate sliding surface is zero or close to zero, the high-pressure oil pump uses one high-pressure oil blowing hole to remove the oil from the stationary plate sliding surface at approximately the center. When high pressure oil is sent to the section, the elastic deformation or concave deformation of the stationary sheet metal increases. This state is shown in FIG. In FIG. 1, αe is an annular rotating plate with an inner diameter Dls and an outer diameter. (In is a stationary plate, r17a) is a fan-shaped stationary plate base metal made of copper metal, and the upper surface is lined with Babbitt metal r17b). This stationary plate (171) is elastically supported on the bearing stand I via a large number of coil springs 08.

(20a) is a small hole for blowing out high-pressure oil near the center of the sliding gap of the stationary plate +171, and (21a) is an oil feed hole.

When starting the main engine from a stopped state, under conditions where the thermal deformation in the radial direction on the rotating plate side is zero or close to zero, when high-pressure oil is blown from the small hole r20a by a high-pressure oil pump (not shown), the stationary plate Q71 The central part is recessed by a dimension of Δ2, resulting in a minute oil film H-M, N on the inner and outer diameter sides. The oil film pressure distribution at this time becomes a mountain shape with a maximum value P, as shown by the curve connecting the vertices of the arrows. As is clear from this figure 1, K.

When high-pressure oil is supplied, since the stationary plate base metal R17a) is a copper-based metal with a small elastic modulus, the concave forced deformation becomes excessively large, and the oil film thickness on the inner and outer sides of the stationary plate decreases to provide lubrication. Stones create an unstable state called boundary lubrication, which causes bearing burnout. This instability phenomenon caused by a decrease in the thickness of the oil film, which causes burnout, disappears as the rotating plate of the thrust bearing increases in speed, but it is an extremely dangerous phenomenon.

[Purpose of the invention]

The present invention is a method for starting a thrust bearing device that can significantly reduce bearing loss during steady operation, and that can exhibit stable thrust bearing performance when starting a thrust bearing device that operates at high circumferential speeds and with large loads. The purpose is to provide

[Summary of the invention]

In the present invention, the high-pressure oil pump has a rotational speed of at least 30 degrees of the main engine rated rotational speed when starting the main engine.
The oil film thickness on the inner diameter side and the outer diameter side of the stationary plate is maintained at a desired thickness or more so that the engine can be started safely.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described with reference to FIGS. 2 to 4.

In Figure 2, the rotating shaft (Il
As a bearing device for l, the same oil tank (a thrust bearing device +t31 and a guide bearing device I are installed in 12, among which thrust bearing device 03) is a thrust collar 0511 rotating plate Qe, stationary plate an, coil spring θ It consists of a bearing pedestal, etc. That is, a stepped thrust collar 0ω is fitted on the outer periphery of a vertical rotating shaft (111), and a rotating plate (11) is fastened to the lower end surface of this thrust collar. A plurality of fan-shaped stationary plates Q71 are movably disposed radially around the outer periphery of the rotating shaft Ql), and the stationary plates 07) are elastically supported on a bearing stand (14) via a large number of coil spring barrels. The stationary plate 0η is held in an oil tank H. As shown in FIG. 3, the base metal r17m) is made of copper-based metal, and the upper surface is lined with pavit metal (17b). The upper surface of the stationary plate (17b), which acts as a sliding surface during operation, is provided with small holes C20g) for blowing out high-pressure oil, and there are reservoirs for guiding high-pressure oil from the outer circumferential side of the stationary plate into these small holes ('20a). An oil feed hole (21a) is bored inside the stationary plate aη to form a flow path (21).

Further, a connection metal fitting (22) for supplying oil from the outside to this oil supply hole r21a) is attached to the outer periphery of the stationary plate base metal (17a). Returning to FIG. 2, a high-pressure oil pump (23) is installed outside the oil tank 03, and sucks the lubricating oil (24) in the oil tank a2 through the suction pipe (25) and through the discharge pipe (26). High pressure oil flow path C through check valve (27)
21), and the stationary plate a is supplied through the small hole (20a).
It is designed to blow out onto the slip surface of η. (28) is a drive motor for the high-pressure oil pump (23), which receives electric power from a power source (30) via an electromagnetic switch (29). (31) is a water-cooled pipe through which cooling water is passed to cool the lubricating oil (24).

Therefore, in this embodiment, the high pressure oil pump (23) is used in the high pressure oil pump operation mode as shown in FIG. 4 using the above device. That is, the high pressure oil pump (23) is operated several minutes before starting the main engine, and is stopped within about 30 seconds before starting the main engine.

Next, the effect will be explained.

Since the high-pressure oil pump (23) is stopped within about 30 seconds before starting the main engine, the high-pressure oil supplied between the rotating plate 06) and the stationary plate tiD is evenly distributed as shown in Fig. 5. The pressure distribution becomes almost uniform and the rotating plate (161) and stationary plate (17+
are parallel, and the oil film thickness, indicated by HMfN', is uniform. Fig. 6 shows a curve diagram that actually measured the change in the minimum oil film thickness between the rotary plate Oe and the stationary plate Q71 over time after the high-pressure oil pump (23) stopped, and within 30 seconds. If so, it is clear that a fairly thick oil film remains. Therefore, it has been found that if the main engine is started within 30 seconds after the high-pressure oil pump (23) is stopped, the thrust bearing performance can be exhibited in a stable fluid lubrication state. We were also able to verify through actual load tests that extremely stable lubrication performance was obtained, especially when started within 20 seconds.

FIG. 7 shows the operation mode of another embodiment.

In this example, the high-pressure oil pump (23
).

The rest is the same as the embodiment shown in FIGS. 2 to 4.

Even with this method, if the rotational speed of the rotary plate Q is within 301 of the rated rotational speed, the high pressure oil pump (
It is possible to eliminate the unstable phenomenon that occurs when static pressure fluid lubrication due to 23) and fluid lubrication due to original dynamic pressure check each other, and an unstable state called boundary lubrication does not occur. It was verified that this is essentially the same as the example of the operation mode shown in , and it was confirmed that it can be started safely.

In addition, the operation control of the high pressure oil pump (23) corresponding to the rotational speed of the main engine can be controlled in units of seconds in an actual sequence, and this is unlikely to cause problems when implementing the present invention. It is also possible to apply the present invention to the stationary plate Q71 in which the stationary plate base (17a) is made of iron-based metal, and obtain the same effects as in each of the embodiments described above.

〔Effect of the invention〕

As explained above, according to the present invention, the high-pressure oil pump is stopped at least before the rotation speed reaches 30 inches of the main engine rated rotation speed at the time of starting the main engine, so that This is a method for starting a thrust bearing device for high circumferential speed and large loads, which maintains the oil film thickness on the radial side at a desired thickness or more and allows safe starting.

[Brief explanation of drawings]

Fig. 1 is a vertical sectional view of the right half of the thrust bearing device when the conventional starting method is implemented, Fig. 3 is a perspective view showing the stationary plate of Fig. 2, and Fig. 4 is the device of Fig. 2. Figure 5 is an explanatory diagram showing the state of oil film formation and oil film pressure distribution in the thrust bearing device after the high pressure oil pump stops and starts in Figure 4. 2 is a curve diagram showing the temporal change in the minimum oil film thickness between the rotary plate and the stationary plate after the high-pressure oil pump of the apparatus shown in FIG. 2 is stopped, and FIG. 7 is an operation mode diagram of another embodiment. [1... Rotating shaft 12... Oil tank 15... Thrust collar 16... Rotating plate 17...
・Stationary plate 18...Coil spring 19 which is an elastic member...Bearing stand 20a which is a support member...Small hole 2 which is a discharge port...Flow path 23...High pressure oil pump 24...・
Lubricating oil agent Patent attorney Inoue - Rikitsutsu 1 Figure 2 Figure A 3 C 4 Figure 5 Figure 6 Otz J Figure 7 High E-n insect pump 2. Ne-21shi-F - Elbow open

Claims (2)

[Claims] (1) A rotating shaft of a main machine such as a spindle rotating electric machine, a thrust collar that rotates integrally with this rotating shaft, a rotating plate provided on the lower end surface of this thrust collar, and an oil tank that extends radially around the rotating shaft. a plurality of stationary plates disposed in lubricating oil and slidably supporting the rotary plate; a support member supporting these stationary plates via a cicada member; A flow path is provided with a discharge port that penetrates and opens to the upper surface of the stationary plate, and a high-pressure oil pump is installed outside the oil tank for introducing high-pressure lubricating oil into the flow path and discharging it to the upper surface of the stationary plate. In the starting method for a thrust bearing device equipped with
A method for starting a thrust bearing device, characterized in that the main engine is stopped at least before the rotational speed at the time of starting the main engine reaches 30 degrees of the rated rotational speed of the main engine. (2) The method for starting a thrust bearing device according to claim 1, wherein the high-pressure oil pump is stopped within 30 seconds before starting the main engine.