JPS61149614A - Static pressure bearing - Google Patents

Abstract

PURPOSE:To reduce driving energy of power source of fluid supplied without changing load capacity of a bearing by making effective area of supplying hole of the side to which load of static pressure bearing is applied smaller than that of supplying hole of the side to which load is applied. CONSTITUTION:A bearing 1 is divided into two upper and lower sections by a horizontal plane X passing the center, and an air supplying hole 2 is provided on the upper half side 6 to which load is not applied, and an air supplying hole 2a is provided on the lower half side to which load is applied. And the diameter of the air supplying hole 2a of the side to which a bearing is applied is set to an optimum designing condition, that is, a diameter d of an air supplying hole which gives maximum load capacity M, and the hole is drilled. As a diameter of the air supplying hole 2 of the side to which load of the bearing 1 is not applied is made smaller than that of the air supplying hole 2a as load capacity can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a hydrostatic bearing, and more particularly to a hydrostatic gas syringal bearing.

[Prior art]

In general, static pressure bearings use a fluid (usually air) that applies pressure from the outside to the bearing clearance between the bearing and the journal (shaft) in order to prevent bearing wear or seizure due to startup S friction, low-speed RFL friction, etc. is used, so it will be explained below as air)
The shaft is suspended or floated within the bearing while the shaft remains stationary or at low speed.

When this conventional static pressure gas journal bearing is shown in FIGS. 3 and 4, a plurality of air supply holes (supply holes) 12 are provided in the bearing 11, and air fed under pressure from an external air source is supplied to the air supply holes. 1
2 to create pressure in the bearing gap 13. The shaft 14 floats due to the pressure generated within the bearing clearance 13, and during rotation, it is possible to rotate with low friction due to the extremely low viscosity of gas (1/1000 to 1/10000 of the viscosity of oil). (For example, Japan Society of Mechanical Engineers Transactions No. 3
Part 33-255 @, November 1962 issue (Refer to Stability of Hydrostatic Gas Journal Bearings J).

(Problem to be solved by the invention) However, in such conventional hydrostatic gas journal bearings, all the diameters of the air supply holes are the same, so the direction of the load applied to the bearing is determined by the direction of gravity. As shown in the figure, when the bearing is used only downward and in one direction, the same amount of air is forced into the unloaded bearing side as the loaded side, which consumes extra external power to supply the air. There was a problem with this.

The present invention was made in view of these conventional problems, and provides a hydrostatic bearing that can reduce the driving energy of the power source for supply fluid without significantly changing the load capacity of the bearing. The purpose is to

(Structure of the Invention) In order to achieve the above object, the present invention is such that the effective area of the supply hole on the unloaded side of the hydrostatic bearing is made smaller than the effective area of the supply hole on the loaded side.

(Function) The change in load capacity with respect to the effective diameter of the supply hole forms a curve that gives the maximum value for a certain value, so even if the dimensions are made smaller or larger than this, the load capacity will decrease. It turned out that. Therefore, in this invention, the diameter of the supply hole on the side where the load is applied is set to a size that provides the maximum load capacity, and the diameter of the supply hole on the side where the load is not applied is set smaller than this. As a result, the loaded side has the maximum capacity, and the non-loaded side has a corresponding capacity.In the end, the bearing maintains its overall load capacity, and the smaller supply hole diameter reduces the drive energy of the power supply source. I was able to do that.

〔Example〕

FIG. 1 is a diagram showing an embodiment of the present invention.

First, to explain the structure, the bearing 1 is divided into upper and lower parts by a horizontal plane It has an air supply hole 2a. The diameter of the air supply hole 2 is designed to be smaller than the diameter of the air supply hole 2a. Here, the direction of the load is the direction of gravity, which is indicated by a downward arrow.

In this case, the diameter of the air supply hole 2a on the load side 5 is designed to be an optimal design (described later).

A bearing clearance 3 is formed between the journal 4 and the bearing 1,
Air is forced into this gap 3 through the air supply holes 2 and 2a. This causes the journal to surface.

Next, the effect will be explained. When the shaft diameter, bearing clearance, and other geometrical parameters are fixed and only the air supply hole diameter is changed, the load capacity @W exhibits a chevron curve with a maximum fl1M, as shown in FIG.

Therefore, the diameters of the 15 air supply holes 2a on which the load of the bearing 1 is applied are set to the optimal design conditions, that is, the air supply hole diameter d that provides the maximum load capacity IM, and the holes are bored. The diameter of the air supply hole 2 on the non-loaded side 6 of the bearing 1 requires a small load capacity;
The hole is made smaller than the air supply hole 2a.

Therefore, regarding the load capacity of the C1 bearing 1 in the load direction, it is possible to obtain the same maximum load capacity as in the conventional case.

Furthermore, regarding the load capacity on the side 6 on which no load is applied, there is no need for any capacity on the load side, and a corresponding load capacity is obtained. As a result, the bearing 1 as a whole maintains the same load capacity as the conventional bearing.

Furthermore, since the air supply holes 2 of 116 which are not loaded are small, the collapse of the supply air flow can be reduced, thereby making it possible to reduce the driving energy of the air supply power source accordingly.

FIG. 5 shows an example in which the above-described embodiment is applied to an automobile turbocharger.

The turbine 21 is integrally connected to a compressor 23 by a shaft 22, and is rotated by the exhaust gas flowing through the scroll 24 to the outlet portion 25a, thereby rotating the compressor 23 to compress the supply air, and from the scroll 25 to an engine (not shown). send to

The shaft or journal 22 is supported in a bearing 26 which fits into a center housing 27. A heat insillator 28 is provided between the center housing 27 and the right scroll 24, and a heat insulator 28 is provided between the center housing 27 and the right scroll 24.
5, back plates 29, 30 and 31 are sequentially provided.

Thrust collars 33 and 34, which receive left and right thrust of the rotor 32, are in contact with both sides of the back plate 30, 31.

Air is supplied from the supply power source P to the journal port 35 and the thrust port 36.

The journal holes 35 communicate through annular passages 37 with air supply holes 38 arranged in four rows in the axial direction and eight equally spaced on the circumference. Exhaust after the bearing action is completed is through the exhaust port 39.
and is discharged to the outside from the outlet 40.

In the above example, since the rotor 32 is installed horizontally, an additional load is applied in the direction of gravity by the weight of the rotor 32. At the time of design, the diameter of the lower air supply hole 38 is set to an optimum size in consideration of the direction of gravity, and the diameter of the upper air supply hole 38 is set smaller than this. By doing so, the flow rate of the supplied gas can be reduced and the pump power can be reduced.
Eight air supply holes 42 are arranged equally on the circumference of the back plates 30 and 31 through an annular passage 41 provided in the
and 43, air is supplied to the thrust portions of the thrust collars 33 and 34, and the exhaust air is appropriately discharged from a flange (not shown) of the center housing 27, etc. Note that since gravity has no bearing on the thrust bearing, the air supply holes are uniform and optimally designed according to each load capacity.

The above is an example of application to an automobile turbocharger, but other specific examples include large turbo machines such as gas turbine engines for passenger cars or buses, which have a large shaft diameter, a large shaft weight, and are heavy due to their own weight. It is particularly effective when applied to bearings with large eccentricity.

〔Effect of the invention〕

As explained above, according to the present invention, the structure is such that the effective area of the supply hole on the non-loaded side of the hydrostatic bearing is smaller than the effective area of the supply hole on the loaded side. While maintaining the load capacity of the bearing, the supply pressure flow rate can be reduced, and the driving energy of the supply power source can also be reduced.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing one embodiment of this invention □, Fig. 2 is a load capacity performance diagram with respect to the air supply hole diameter, Fig. 3 is a cross-sectional view of a conventional device, and Fig. 4 is a - of Fig. 3. 5 is a cross-sectional view of an application example of an automatic heavy-duty turbocharger. Explanation of symbols shown in the drawings 1.11...bearing, 2.12.12a...supply hole (air supply hole) 3.13...
・Bearing clearance 4.14...Shaft (Ginal), 5...Loaded side 6...Non-loaded side Patent applicant Nissan Motor Co., Ltd. si Figure 2 Figure 2■

Claims (1)

[Claims] The bearing has a plurality of supply holes, the bearing and the shaft supported by the bearing form a bearing clearance, and fluid pumped from the outside passes through the supply holes and generates pressure in the bearing clearance, causing the shaft to float. What is claimed is: 1. A hydrostatic bearing, characterized in that the effective area of the supply hole on the unloaded side of the bearing is smaller than the effective area of the supply hole on the loaded side.