JPS6238567B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement of a bearing device for a vertical rotating machine.

An example of an oil film bearing and a damper of a conventional vertical rotating machine is shown in Fig. 1. 01 is a bearing box, 02 is a rotating shaft, 03 is a spiral groove provided at the end of the rotating shaft 02,
04 is the bearing, 05 is the gap between the spiral groove 03 and the bearing 04, 06 is the oil film chamber between the tip of the rotating shaft 02 and the bearing 04, 07 is the floating plate, and 08 is the bearing 04 and the floating plate 0.
7, 09 is a steel ball supporting bearing 04, 0
10 is lubricating oil.

When the rotating shaft 02 rotates, the lubricating oil 010 is trapped in the gap 05 by the action of the spiral groove 03, and the oil film chamber 06 becomes under high pressure.

In this way, an oil film is formed in the gap 05 and the oil film chamber 06 to obtain a smooth lubricated state. Bearing 0
Since the bearing 4 has a structure that allows it to move very easily in the radial direction, when the rotating shaft 02 rotates and generates vibration, the bearing 04 vibrates accordingly. Therefore, the bearing 04 and the floating plate 0 placed on its top surface
A relative movement with 7 occurs. Therefore, oil is forced into the gap 08 and forms an oil film. Here floating board 0
Since the gap between the bearing box 7 and the bearing box 01 is relatively small and filled with oil, movement of the floating plate 07 in the radial direction is difficult to occur, so the bearing 04 has a gap of 0.
It is subjected to shear resistance force due to the oil film at part 8. This structure uses shear resistance force as viscous damping force to stabilize the rotating system.

However, the oil film thickness in the gap 08, which determines the damping effect, is affected by the magnitude of the vibration of the bearing 04;
In addition, if the floating plate 07 is lightweight, the gap is 0.
There are drawbacks such as unstable damping characteristics due to the fact that the oil film thickness of No. 8 is easily influenced by external conditions.

Therefore, in order to keep the oil film thickness in the gap 08 constant, there is a structure in which the floating plate 07 is mechanically fixed to the bearing box 01, but in order to make the oil film thickness very thin,
Since high precision is required and the cost is high, we took advantage of the accuracy of the conventional structure (conventional structure does not require high precision because the oil film thickness is determined by the vibration of the bearing 04) and stabilized the damping characteristics. It is an object of the present invention to measure this.

An embodiment of the present invention is shown in FIG. 2. Reference numeral 1 denotes a bearing box, 2 a rotary shaft extending vertically and having a spiral groove 3 at its lower end, and inserting this lower end into the bearing box 1; A bearing is disposed within the bearing box 1 to support the rotating shaft 2, and is connected by a spring element (not shown) to maintain the center of the bearing 4 and prevent it from turning. 5 is a gap between the helical groove 3 and the bearing 4, and 6 is an oil film chamber provided in the bearing 4, which surrounds almost the entire helical groove 3. 7 is a floating plate; 8 is a flat surface 10 of the bearing 4 that faces the horizontal lower surface 9 of the floating plate 7;
11 is an annular groove provided on the flat surface 10, 12 has one end connected to the annular groove 11, and the other end connected to the oil film chamber 6.
Communication passages are opened at the bottom, 13 is a steel ball that supports the bearing 4, and 14 is lubricating oil.

Next, to describe the action, when the rotating shaft 2 rotates,
Due to the action of the spiral groove 3, oil is trapped in the gap 5, and the oil film chamber 6 becomes under high pressure. This pressure is applied to the communication passage 12,
The oil is transmitted through the annular groove 11 to the gap 8 between the horizontal surface 9 and the flat surface 10, pushing up the floating plate 7 and forming an oil film. The shear resistance of this oil film is used to provide a vibration absorbing effect.

In this embodiment, since the pressure in the oil film chamber 6 is almost determined by the thrust load of the bearing 4, the force pushing up the floating plate 7 is almost constant, so the thickness of the oil film formed in the gap 8 becomes almost constant,
Therefore, the damping characteristics can be stabilized.

Figure 3 shows another embodiment, and the structure shown in Figure 3 is suitable for rotating machines where the bearing load fluctuates and the oil film thickness fluctuates, or where the weight of the floating plate is insufficient. There is.

FIG. 3 shows the bearing box 1 and floating plate 7 in FIG. 2 connected by a spring 15. As the thrust load increases, the pressure inside the annular groove 11 increases, and the oil film thickness in the gap 8 increases. However, the spring force also increases and counteracts the force that tries to push up the floating plate 7, so changes in the oil film thickness can be kept small, and even if the thrust load fluctuates, the oil film thickness does not change. Since the fluctuations are small, the damping characteristics are stable.

FIG. 4 shows yet another embodiment, which has a structure that can be adopted when the bearing load is relatively small, and unlike FIGS. 2 and 3, a gap 8 is provided between the bearing box 1 and the bearing 4. , on the other hand, the steel ball for thrust support (1 in Fig. 2)
3) has been abolished and the structure is supported by an oil film, so
When the rotating shaft 2 rotates, oil is trapped in the gap 5 by the action of the spiral groove 3, and the pressure in the oil film chamber 6 increases. This pressure is transmitted to the gap 8 via the communication passage 12 and the annular groove 11, floats the bearing 4, forms an oil film, and obtains a substantially constant oil film thickness, making it possible to obtain stable damping characteristics and By adopting a structure in which the entire bearing portion is supported by an oil film, the movement of the bearing 4 can be made smooth.

In addition, in FIGS. 3 and 4, the same cylinder locations as in FIG. 2 are given the same numbers as in FIG. 2.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional view of a conventional bearing device for a vertical rotating machine, FIG. 2 is a vertical sectional view of one embodiment of the present invention, and FIGS. 3 and 4 are respectively of other embodiments of the present invention. FIG. 1: Bearing box, 2: Rotating shaft, 3: Spiral groove, 4: Bearing, 5: Gap, 6: Oil film chamber, 8: Gap, 9: Bottom surface, 10: Flat surface, 11: Annular groove, 12: Connection Passage, 14: Lubricating oil.

Claims (1)

[Claims] 1. A bearing box filled with oil, a rotating shaft extending vertically and having a spiral groove at its lower end, and having the lower end inserted into the bearing box, and a rotating shaft disposed within the bearing box and configured to rotate the rotating shaft. a bearing for supporting a shaft, the bearing having an oil film chamber surrounding almost the entire area of the spiral groove, a flat surface facing a horizontal surface in the bearing box, and an oil film chamber provided on the flat surface. 1. A bearing device for a vertical rotating machine, comprising: an annular groove; and a communication passage having one end opened in the annular groove and the other end opened in a lower part of the oil film chamber.