JPS6122172B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a lubricating oil supply and discharge control device for an elliptical bearing.

Generally, elliptical bearings are used as bearings to support rotors of turbine generators, turbo compressors, etc. that are subject to heavy loads and rotate at high speed.
As shown in the figure, an upper half-bearing body 2a and a lower half-bearing body 2b, which are also horizontally divided into two, are provided in an upper half-bearing outer ring 1a and a lower half-bearing outer ring 1b, which are also horizontally divided into two. A lubricating oil supply path 4 is provided to the rotating shaft 3 as a sliding bearing, and further to the bearing portion which is the sliding portion between each bearing body 2a, 2b and the rotating shaft 3.
and a lubricating oil discharge path 5 so that lubricating oil 6 is forcibly supplied and discharged. In addition, each bearing outer ring 1a, 1b and each bearing body 2a, 2b
The bearings are connected to each other by feed bolts 7 and 8, respectively, and the bearing outer ring and the bearing main body are connected to each other by a rotation stop pin 9 provided between the upper half bearing outer ring 1a and the upper half bearing main body 2a. Relative movement in the direction is not possible. The elliptical bearing thus formed is positioned at an appropriate position on a bearing mounting base (not shown) by applying adjustment pads 10 to the lower surface of the lower half bearing outer ring 1b, and is fixed with fixing bolts 11.

This elliptical bearing has a large load capacity, and supports the rotating shaft 3 with a more appropriate preload coefficient or ellipticity by adjusting the relative distance between the upper half bearing body 2a and the lower half bearing body 2b with the connecting bolt 8. Therefore, it has advantages such as superior bearing stability compared to true circular bearings.

However, as the capacity and efficiency of turbo machinery has increased in recent years, the diameter of the rotating shaft to be supported has increased.
Furthermore, in the high peripheral speed and high rotational speed range of the rotating shaft due to the increased speed of the rotor, there is a problem in that the rotating shaft etc. vibrate due to oil whip and the like.

In order to eliminate these disadvantages, conventionally, as shown in FIG. 1, a circumferential groove 13 having a depth d extending in the entire circumferential direction is formed in the inner circumferential surface 12 of the lower half bearing body 2b.
An elliptical bearing that supplies a large amount of lubricating oil to the bearing has been proposed.

However, in an elliptical bearing, the bearing average surface pressure also changes with changes in operating conditions, so simply forming the circumferential grooves 13 as described above does not always maintain the appropriate oil pressure in the bearing portion. Therefore,
Under operating conditions where the bearing average surface pressure is low and where oil whip is likely to occur, the effect of providing the circumferential groove 13 is halved, and under operating conditions where the bearing average surface pressure is high, the lubricating oil supplied into the bearing is A large amount of lubricating oil flows into the bearing, reducing the amount of lubricating oil required for the bearing, resulting in unstable vibration due to lack of lubricating oil in the bearing and high temperature of the bearing metal due to insufficient cooling. There were disadvantages such as a reduction in bearing load capacity, burnout, etc.

The present invention has been made in view of these points, and includes providing a lubricating oil supply/discharge path for directly supplying and discharging lubricating oil to a circumferential groove formed on the inner circumferential surface of the lower half bearing body, and also provides a lubricating oil supply/discharge path for directly supplying and discharging lubricating oil. The system is equipped with pressure gauges, controllers, etc. that open and close various valves for supplying and discharging lubricating oil installed in the supply and discharge passages according to the state of the oil pressure in the bearing, and the oil pressure in the bearing is controlled under all operating conditions of the elliptical bearing. It is an object of the present invention to provide a lubricating oil supply/discharge control device for an elliptical bearing that can properly hold a rotating shaft particularly in a high-speed operating range and can stably and safely support a rotating shaft.

Hereinafter, the present invention will be described with reference to embodiments shown in FIGS. 2 to 5.

As shown in FIG. 2, the inner circumferential surface 12 of the lower half bearing body 2b has a circumferential groove 1 having a length L of a portion of the circumferential length at the lowest portion where the maximum bearing load acts.
4 is formed in this circumferential recessed groove 14, as shown in FIGS.
6 is connected. As shown in FIG. 4, this lubricating oil supply/discharge passage 16 is connected to an oil guide hole 16a which is communicated with the circumferential groove 14 in the lower half bearing body 2b, and this oil guide hole 1.
Oil guide pipe 1 connected to 6a with a cap nut 17
6b. Further, the lubricating oil supply/discharge path 16 is provided with a pressure regulating valve 19 and an auxiliary oil supply regulating valve 20 which are opened when lubricating oil is co-supplied to adjust the amount of supplied lubricating oil, and which are opened when the lubricating oil is drained. A relief oil adjustment valve 22 is provided to adjust the amount of oil discharged to the return oil section 21. As shown in FIG. 4, the lower half bearing body 2a is provided with a pressure detection hole 23 that opens at the smooth portion of the inner circumferential surface 12 and at the position of the circumferential groove in order to detect the oil pressure in the bearing portion. A pressure transducer 24 is attached to each of the pressure detection holes 23, and a pressure gauge 25 is connected to the pressure transducer 24.
Further, the pressure gauge 25 includes a controller 26 that sends valve opening/closing signals to each of the valves 19, 20, and 22 according to the pressure state of the bearing portion, and controls the amount of lubricating oil supplied and discharged by opening and closing each valve by a predetermined amount. It is connected. By the way, the pressure in the groove 14 is determined by the rotational speed, the amount of oil flowing through the groove, and the viscosity, and the pressure in the smooth part is determined by the bearing load, rotational speed, and viscosity. The conditions can be known, and if the oil guide hole 16a is opened on the upstream side (on the left side in FIG. 2) of the minimum oil film pressure part, a good flow of lubricating oil in the bearing part can be formed.

In addition to the oil tank 27, the lubricating oil supply section 15 includes an oil pump 28 and an oil cooler 29. On the downstream side of the oil pump 28, there is an equipment control oil supply pipe 30 that supplies oil for driving equipment. The lubricating oil supply path 16 is connected to the downstream side of the oil cooler 29 and is provided with a bearing oil supply pressure regulating valve 31 in the middle.

Next, the operation of the present invention will be explained based on the pressure characteristic diagram shown in FIG.

FIG. 5 shows the pressure distribution in the bearing portion corresponding to the section taken along line VV in FIG. 2.

Now, the oil pump 28 of the lubricating oil supply section 15 is operated, and the lubricating oil 6 is fed into the bearing from the lubricating oil feeding section 4, and the lubricating oil 6 is also supplied and supplied into the circumferential groove 14. When an oil film with an appropriate hydraulic pressure is formed on the bearing portion and a good bearing is performed, the oil pressure on the bearing portion is formed as shown by the solid line O in FIG.

After that, when the operating conditions change and the bearing average surface pressure increases, the amount of lubricant supplied to the bearing becomes lower than the amount of oil required for lubrication, similar to the conventional bearing shown in Figure 1, and the pressure in the bearing becomes changes as shown by the broken line A in FIG. This pressure change immediately occurs in the pressure detection hole 2.
3 is detected by the transducer 24, and the pressure gauge 2
It appears as a pressure change display of 5. This pressure gauge 2
5, the controller 26 sends a valve opening signal to the auxiliary oil supply regulating valve 20 and the pressure regulating valve 19, opens the lubricating oil supply/discharge passage 16, and directs the lubricating oil through the oil guide hole 16a to the circumferential groove 14. to the inside,
The amount of lubricating oil in the bearing is increased to return the pressure distribution to the position indicated by the solid line O in FIG. At this time, the opening degree of the pressure regulating valve 19 is adjusted so that the pressure for pushing the lubricating oil is appropriate.

Further, when the operating conditions change and the bearing average surface pressure decreases, the amount of lubricating oil in the bearing becomes larger than the required amount, and the pressure distribution changes as shown by the chain line B in FIG. This pressure change is detected by the pressure gauge 25 in the same manner as described above, and the controller 26 receives a command from the pressure gauge 25 to open the relief oil regulating valve 22, and the lubricating oil is supplied from inside the circumferential groove 14 through the lubricating oil supply/discharge path 16. The lubricating oil is directly discharged to the return oil section 21 outside the bearing, and the amount of lubricating oil in the bearing section is adjusted to an appropriate amount to return the pressure distribution to the position indicated by the solid line O in FIG.

In addition, in order to supply and discharge lubricating oil as described above and obtain appropriate oil pressure, the length L of the circumferential groove 14 is determined by the oil supply holes 32 at both circumferential ends of the lower half bearing body 2b,
It is better to have a length that does not reach the oil drain hole 33 (Fig. 2). This is because the lubricating oil supply/discharge via the lubricating oil supply/discharge path 16 can be performed independently of the lubricating oil fed from the lubricating oil feeding path 4, and the pressure distribution can be finely adjusted. Therefore, its length L
may have a length that includes the minimum oil film portion of the bearing during operation, and may be provided within 30 degrees in the circumferential direction around the lowest point of the inner circumferential surface 12, respectively.

In this way, the lubricant supply and discharge control device for an elliptical bearing of the present invention is configured so that the lubricant can be directly supplied and discharged by having a lubricant supply and discharge path to the circumferential groove formed in the bearing. It is possible to finely adjust the amount of lubricant supplied and discharged to the bearing part, and by detecting the lubricant pressure in the smooth part and circumferential groove part of the bearing part, the bearing usage conditions can be directly detected and the lubricant supply and discharge can be adjusted. Since the structure is configured so that the amount of lubricant supplied to and discharged from the bearing is adjusted by opening and closing various valves installed in the bearing, the oil pressure in the bearing can always be maintained at an appropriate level in all operating conditions of the elliptical bearing.
Especially in operating conditions where the bearing average surface pressure is low, vibrations caused by oil whip etc. can be prevented.
In addition, in operating conditions where the bearing average surface pressure is high, a large amount of cooled new lubricating oil can be sent to the bearing to cool the bearing and prevent the bearing metal temperature from increasing. The durability of the elliptical bearing has increased, and even if the operating conditions change over time or suddenly, the proper oil pressure in the bearing can be maintained reliably, improving the safety and stability of the bearing. When the length of the groove is a part of the inner peripheral length of the lower half bearing body, it is possible to achieve effects such as making it possible to more finely adjust the hydraulic pressure of the bearing portion.

[Brief explanation of the drawing]

Figure 1 is a longitudinal cross-sectional side view of a conventional elliptical bearing, Figure 2-
Figure 5 shows an embodiment of the lubricating oil supply and discharge control device for an elliptical bearing of the present invention, Figure 2 is a perspective view of the lower half bearing body, Figure 3 is a line diagram showing the lubricant supply and discharge system, and Figure 3 is a diagram showing the lubricating oil supply and discharge system. 4
The figure is a top perspective view showing another lower half bearing body, and FIG. 5 is a characteristic line diagram showing the hydraulic pressure distribution of the bearing portion in a cross section taken along the line VV in FIG. 2. 2b... Lower half bearing body, 12... Inner peripheral surface, 14... Circumferential groove, 16... Lubricating oil supply/discharge path, 19... Pressure adjustment valve, 20... Auxiliary oil supply adjustment valve, 22... Relief oil adjustment valve, 25... Pressure gauge, 26...controller.

Claims (1)

[Scope of Claims] 1. A lubricating oil supply/discharge path that directly supplies and discharges lubricating oil to a circumferential groove formed in the inner circumferential surface of the lower half bearing body of the elliptical bearing, and an oil serving as the lubricating oil supply/discharge path. A pressure adjustment valve and an auxiliary oil supply adjustment valve provided on the oil supply side of the passage, a relief oil adjustment valve provided on the oil discharge side, and an oil film formed on the bearing portion between the lower half bearing body and the rotating shaft. a pressure gauge that detects the oil pressure at two locations, the circumferential recessed groove portion and the smooth portion; A lubricating oil supply/discharge control device for an elliptical bearing, comprising: a controller that sends an opening signal; and, if the signal is higher than a predetermined oil pressure, sends a valve opening signal to the relief oil regulating valve. 2. The circumferential groove has a length of a portion of the inner peripheral surface of the lower half bearing body in the circumferential direction, and is formed at the maximum bearing load portion of the lower half bearing body. lubricating oil supply and discharge control device for elliptical bearings.