JP2000227117A - Hydrostatic bearing unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To sharply reduce a fluid flow in a hydrostatic bearing without reducing bearing performance. SOLUTION: In this hydrostatic bearing unit which floatingly supporting a rotator 11 by means of lubricating fluid to be fed out of a hydrostatic bearing 13 set up on the circumference of the rotator 11 via its clearance, the hydrostatic bearing 13 is equipped with a recess part 16 interconnected to a pressure chamber 14 supplying the lubricating fluid, a land part 17 supporting the rotator 11 by fluid pressure in the lubricating fluid set up as being adjacent to the recess part 16 via the bearing clearance, and a floating ring seal 18 set up on the downstream side of the land part 17, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydrostatic bearing, and more particularly to a structure of a hydrostatic bearing device for supporting a rotating body such as a rotary shaft of a pump by floating by a fluid pressure of a lubricating fluid.

[0002]

2. Description of the Related Art A hydrostatic bearing is a bearing that supports a rotating shaft with the fluid pressure of a lubricating fluid.
Since it does not cause bearing wear and does not require lubricating oil, it is used as a maintenance-free bearing for supporting a rotating shaft of a pump or the like. Further, by using a part of the water discharged from the discharge side of the pump or the like as the lubricating fluid of the hydrostatic bearing, an oil separator, an oil supply device and the like become unnecessary, and the structure can be made compact. In a machine in which a rotating shaft is supported by a hydrostatic bearing, a relatively large bearing clearance may be required in terms of structure due to shaft vibration and the like. When water, which is the pump's own liquid, is used as the lubricating fluid, water has a lower viscosity than oil, and thus has a disadvantage in that the flow rate of the lubricating fluid to be supplied to the hydrostatic bearing increases.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is possible to significantly reduce the flow rate of a lubricating fluid in a hydrostatic bearing without reducing the performance of the hydrostatic bearing. It is an object of the present invention to provide a hydrostatic bearing device which can be used.

[0004]

According to the present invention, there is provided a hydrostatic bearing device for floatingly supporting a rotating body by a lubricating fluid supplied from a static pressure bearing disposed on the outer periphery of the rotating body via a gap. In the bearing device, the hydrostatic bearing supports the rotating body via a bearing gap by a recess portion communicating with a pressure chamber for supplying a lubricating fluid and a fluid pressure of a lubricating fluid disposed adjacent to the recess portion. A land portion and a floating ring seal disposed downstream of the land portion are provided.

[0005] According to the present invention, the pressurized lubricating fluid passes from the pressure chamber provided between the casing and the bearing to the outside through the throttle, the recess, and the land while supporting the rotary shaft. And flows. At this time, by disposing the floating ring seal downstream of the land, the flow rate of the lubricating fluid can be reduced while maintaining the bearing performance. This can contribute to the efficiency of the pump.

The floating ring seal is
It is preferable that the floating ring seal has a gap equal to or larger than the bearing gap, and that the floating ring seal is further arranged on both sides of the land arranged on both sides of the recess. This allows
Since the floating ring seal has a gap equal to or greater than the bearing gap, without reducing the performance of the bearing,
The flow rate can be reduced. If the gap of the floating ring seal is smaller than the bearing gap,
Although the effect of reducing the flow rate is large, performance such as bearing rigidity is significantly impaired. In addition, by arranging the floating ring seal on both sides of the lands arranged on both sides of the recess, the lubricating fluid is equally divided from the pressure chamber, and the load capacity of the hydrostatic bearing is reduced by the lands on both sides. You can get a good balance. Also, the flow rate of the lubricating fluid can be reduced on both sides of the bearing.

Further, it is preferable that the static pressure bearing is used for supporting a rotating shaft of the pump, and uses a part of the discharge liquid of the pump as a lubricating fluid. Thereby, the efficiency of the self-liquid lubrication type pump can be improved.

[0008]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a diagram showing a main part of a hydrostatic bearing device according to an embodiment of the present invention. A bearing member 13 is disposed in the casing 12, and supports the rotating shaft 11 by a fluid pressure of a lubricating fluid. From the pressure chamber 14 provided between the casing 12 and the bearing member 13, the pressurized lubricating fluid passes through the throttle part 15 and the recess part 16 and the land part 17 and the rotary shaft 1.
1 is supplied to the gap between them. In this embodiment, the lands 17 and 17 are arranged on both sides of the recess 16, and the pressurized fluid supplied from the pressure chamber 14 flows into both sides approximately in two parts, and the lubricating fluid The rotating shaft 11 is levitated and supported at a substantially central position by the fluid pressure. still,
The pressure chamber 14 communicates with the discharge side of a pump (not shown), and the self-liquid pressurized by the pump is supplied to the pressure chamber 14. Although the bearing members 13 and 13 are shown in the vertical direction in this figure, similar bearing members are also arranged in a direction perpendicular to the paper surface, and although not shown, the bearing members 13 and 13 are arranged around the rotation shaft 11. A total of six bearing members are arranged. The number is not limited to six, but may be four or eight.

In this hydrostatic bearing device, the bearing member 1
3 are provided with floating ring seals 18 on both sides. The floating ring seal 18 is a lightweight floating ring made of, for example, carbon, and is freely movable in the axial direction and the radial direction between the bearing member 13 and the plate-shaped body 19 at the outer end thereof. At this time, the rotating shaft 1
When the lubricating fluid is a low-viscosity fluid such as water, the flow rate of the lubricating fluid is increased as described above when the bearing gap C, which is the distance between the lubricating fluid 1 and the land 17, is large. Normally, the flow rate of the lubricating fluid can be reduced by increasing the axial length of the land portion 17 or reducing the axial length of the recess portion 16. However, in this case, when shaft vibration or the like occurs, the rotating shaft 11 may come into contact with the land portion 17, which is not preferable. Therefore, in this embodiment, the floating ring seal 18 described above is loosely fitted on both outer sides of the land portion 17.

This floating ring seal 18
By having a gap Cr equal to or greater than the gap C between the lands and the rotating shaft 11, it has an effect of blocking the lubricating fluid flowing to the outside, thereby reducing the flow rate of the lubricating fluid. can do. And since the gap Cr of the floating ring seal is equal to or larger than the gap C of the land portion 17, when the position of the rotating shaft 11 is deviated, a large reaction force acts on the narrow gap side,
A small reaction force acts on the wide gap side, and a fluid static pressure acts to return the rotating shaft 11 to a substantially center position. Therefore, performance such as rigidity of the bearing is not significantly reduced by the hydrostatic pressure. In general, a floating ring seal is lightweight and has good follow-up properties with respect to shaft vibration, so that it is less likely to come into contact with the rotating shaft 11 or the bearing member 13 and may be damaged due to its high wear resistance. Is low.

FIG. 2 is a diagram showing the load capacity with and without the floating ring seal. The abscissa indicates the eccentricity, where 0 indicates the case where the rotating shaft is located at the center of the bearing, and 1 indicates the state where the eccentricity and the rotating shaft are in contact with the land. The vertical axis is the load capacity (Newton).
The solid line shows the case without the floating ring seal, and the dashed line shows the case with the floating ring seal and the gap (Cr = 150 μm) between the inner peripheral surface of the floating ring seal and the rotating shaft. In addition, the two-dot chain line indicates that there is a seal, and the gap between the inner peripheral surface of the seal and the rotating shaft (Cr = 10
0 μm). Here, the dimensions of the hydrostatic bearing are as follows: the rotating shaft diameter D is 100 mmφ, the length L is 100 mm, the bearing gap C is 100 μm, the number of pockets Nr is 6,
The length Lr is 80 mm and the orifice diameter Dr is 3.0 mm
It is. The floating ring seal has an axial length Lf of 10 mm, and as described above, experiments have been conducted with two types of gaps Cr between the rotating shaft: 100 μm and 150 μm.

FIG. 3 is a diagram showing the flow rate with and without the floating ring seal. The abscissa indicates the eccentricity, where 0 indicates the case where the rotating shaft is located at the center of the bearing, and 1 indicates the state where the eccentricity and the rotating shaft are in contact with the land. The vertical axis is the flow rate (L / min). And
The solid line shows the case without the floating ring seal,
The dashed line indicates the floating ring seal, and the gap between the inner peripheral surface of the floating ring seal and the rotating shaft (Cr = 1)
50 μm). The two-dot chain line indicates the case where the floating ring seal is provided and the gap (Cr = 100 μm) between the inner peripheral surface of the floating ring seal and the rotating shaft.

As can be seen from these figures, by providing a floating ring seal, the gap can be reduced by 150.
In the case of μm, the load capacity decreases slightly and
Its flow rate also drops slightly. On the other hand, when the floating ring seal has a gap of 100 μm,
Although the load capacity is greatly reduced, the flow rate can be significantly reduced. This allows the diameter of the floating ring seal to be equal to or greater than the land gap C.
By adjusting so that the load capacity and the flow rate can be largely adjusted, it is possible to appropriately select the load capacity and the flow rate in accordance with the characteristics of the device to which the hydrostatic bearing device is mounted.

[0015]

As described above, according to the present invention, the hydrostatic bearing is provided with the floating ring seal on the downstream side of the land for supporting the rotating shaft thereof, without deteriorating the performance as the bearing. Thus, the flow rate of the lubricating fluid can be significantly reduced. Thus, when a hydrostatic bearing is used for a rotary machine such as a pump, the structure can be greatly simplified, and the self-liquid can be used as a lubricating fluid, and the efficiency can be improved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a main part of a hydrostatic bearing device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a change in load capacity due to a floating ring seal.

FIG. 3 is a diagram showing a change in a flow rate of a lubricating fluid by a floating ring seal.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Rotation shaft 12 Casing 13 Bearing member 14 Pressure chamber 15 Restricted part 16 Recess part (pocket part) 17 Land part 18 Floating ring seal 19 Plate-shaped body

Claims (3)

[Claims] 1. A hydrostatic bearing device for floatingly supporting a rotating body by a lubricating fluid supplied from a hydrostatic bearing disposed on the outer periphery of the rotating body via a gap, wherein the hydrostatic bearing supplies a lubricating fluid. A recess communicating with the pressure chamber, a land supporting the rotating body through a bearing gap by a fluid pressure of a lubricating fluid disposed adjacent to the recess, and a land disposed downstream of the land. And a floating ring seal. 2. The floating ring seal has a gap equal to or greater than the bearing gap, and the floating ring seal is arranged on both sides of a land arranged on both sides of the recess. Item 2. The hydrostatic bearing device according to item 1. 3. The hydrostatic bearing according to claim 1, wherein the hydrostatic bearing is used to support a rotating shaft of the pump, and uses a part of the discharge liquid of the pump as a lubricating fluid. Bearing device.