JPS59166712A - Static pressure bearing - Google Patents

Abstract

PURPOSE:To prevent the displacement of a rotary shaft, by forming three pressure chambers in an internal peripheral wall of the main unit of a bearing while variable throttle flow paths between a diaphragm and throttle wall parts so as to supply a lubricant to the pressure chambers through these variable throttle flow paths. CONSTITUTION:Forming three pressure chambers 13a-13c at an equal space in an internal peripheral wall of the main unit 12 of a bearing while variable throttle flow paths 22 between a diaphragm 17 displaced in accordance with a change of pressure in the pressure chambers 13a-13c and throttle wall parts 18, a lubricant of high pressure is supplied to the pressure chambers 13a-13c through these variable throttle flow paths 22. In this way, if a pressure in the chambers 13a-13c becomes a high level, the variable throttle flow paths 22 are spread allowing the lubricant of high pressure of flow into these pressure chambers 13a-13c, thus the displacement of a rotary shaft 11 caused by the change of a load can be prevented before its occurrence.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydrostatic bearing designed to prevent the relative position of a rotating shaft from changing with respect to a bearing supporting the rotating shaft even if a load fluctuation occurs on the rotating shaft.

As shown in FIG. 1, which shows the concept of a conventional static pressure bearing, a plurality (four in the illustrated example) of pressure chambers 3a are arranged at equal intervals on the inner circumferential wall of a bearing body 2 through which a single rotation shaft 1 passes. ~3d, and a high pressure lubricant supply source 4 that supplies high pressure lubricant and these pressure chambers 3a~3d are connected to throttle passages 5a~5d, respectively.
It has a structure in which it is connected to a conduit 6 via a. Hydrostatic bearings are used in machine tools such as grinders and other industrial machinery that require strict dimensional control and high-speed rotation.
It is desirable that the relative position of the rotating shaft with respect to the bearing does not change even if a load change occurs on the rotating shaft.

However, in the conventional hydrostatic bearing shown in Fig. 1,
For example, when a downward load acts on the rotation lll11, the pressure of the lubricant in the lower pressure chamber 3C increases, and at the same time, the pressure of the lubricant in the lower pressure chamber 3C increases. Since the pressure of the lubricant in a decreases, the lubricant pressure difference at both ends of the lower throttle passage 5C becomes smaller, and the lubricant pressure difference at both ends of the upper throttle passage 5a increases. , the flow rate of lubricant to the lower pressure chamber 3c decreases and the flow rate of lubricant to the upper pressure chamber 3a increases. As a result, the gap between the lower pressure chamber 3C and the rotating shaft 1 narrows, and the gap between the upper pressure chamber 3a and the rotating shaft l widens.91 The rotating shaft 1 is relative to the bearing body 2. This results in a downward displacement and a transition to a new equilibrium state.

As described above, conventional hydrostatic bearings have the disadvantage that the position of the rotating shaft changes due to load fluctuations on the rotating shaft, resulting in a deterioration of the dimensional accuracy of the product, for example in machine tools.

In view of the fundamental drawbacks of the conventional hydrostatic bearings described above, the present invention provides a hydrostatic bearing designed to make it difficult for the relative position of the rotating shaft to change even if there is a load change on the rotating shaft. With the goal.

The structure of the hydrostatic bearing of the present invention that achieves this objective is as follows:
A radial tire flange that partitions the inside of a sealed caning into three equal chambers, and a diaphragm wall that is formed in each of the three chambers in a sealed state and faces the tire flam in a close state. A high-pressure lubricant supply source that supplies high-pressure lubricant into each of these three q partition chambers, and a high-pressure lubricant supply source that is formed at equal intervals on the inner peripheral wall of the bearing body through which the one-rotation shaft passes, and that is located outside the partition chamber. Three pressure chambers each communicate one-to-one within the chamber, and the diaphragm and the diaphragm are connected to each other by perforating each wall of the partition chamber and communicating between the inside and outside of the partition chamber. The lubricant supply hole forms a variable throttling multi-flow path for the lubricant between the lubricant supply hole and the wall portion.

Hereinafter, one embodiment of a hydrostatic bearing according to the present invention will be described in detail with reference to FIG. 2, which schematically shows the structure thereof. Three pressure chambers 13a to 13c are formed at equal intervals on the inner circumferential wall of the cylindrical bearing body 12 through which the rotation axis 11 passes, and each has a constriction. l) 14a to 14cf: The rotating shaft 11 is rotatably supported at the center of the bearing body 2 by the pressure of the lubricant supplied to these pressure chambers 13a to 13c via the lubricant. . On the other hand, a radial diaphragm 17 is attached to the cylindrical sealed coos song 15 to equally partition the coos song 15 into three chambers 16a to 16c. 16a to 16c are partitioned chambers 1 in a sealed state, which are provided with a diaphragm wall 18 that faces the diaphragm 17 in close proximity.
9a to 19c are formed, respectively.

A high-pressure lubricant supply source 20 for supplying high-pressure lubricant is connected to each of these partition chambers 19a to 19c via a conduit 21.
and the diaphragm 17.
A lubricant supply hole 23 communicating with the lubricant supply hole 2 is bored. Therefore.

The high-pressure lubricant is filled from the partitioned chambers 19a to 19c through the lubricant supply hole 23 into the rooms 16a to 16c outside of the partitioned multichambers 19a to 19c. The rooms 16a-L6c to and from these partitioned rooms 19a and 19c and the aforementioned ridges 14a to 14c are conduits 24f:
The lubricant in the chambers 16a to 16c is connected to the pressure chambers 13a to 13c through these conduits 24 on a one-to-one basis.
It is designed to be sent to the side.

Therefore, for example, when a downward load is applied to the rotating shaft 11 in the figure, the pressure of the lubricant in the lower pressure chamber 13b increases, the pressure in the corresponding chamber 16b increases, and conversely, the pressure in the upper chamber 13b increases. The pressure of the lubricant in the two pressure chambers 13a, 13e decreases, and the pressure in the corresponding chambers 16a, 46c decreases, so the diaphragm 17 is displaced upward, causing the patterned walls of the partition υ chambers 19a, 19c to decrease. 18 and diaphragm■7
As the throttle channel 22 between the partition chamber 19b becomes narrower and the
The throttle channel 22 between the throttle wall 18 and the tire diaphragm 17 widens.

As a result, the high-pressure lubricant in the partition chambers 19a and 19c becomes difficult to flow out from their lubricant supply holes 23, while a large amount of the high-pressure lubricant in the partition chamber 19b flows into the chamber 16b.
Because it is discharged inside.

The flow rate of lubricant to the two upper pressure chambers 13a and 13c increases significantly, as does the flow rate of lubricant to the lower pressure chamber 13b, and the 1-rotation shaft 11 is lubricated to lift it upward. The pressure of the agent acts to balance the load on the lower side. The bending rigidity of the knob and diamond ram 17 and the variable throttle multi-flow path 22
By appropriately selecting the width and width, it is possible to generate a lubricant pressure equal to the load on the rotating shaft 11 in the opposite direction to this load, and it is possible to keep the rotating shaft load 1 at a constant position with respect to the bearing body 12. can be held.

In this way, according to the hydrostatic bearing of the present invention, a variable throttle flow path is formed between the diaphragm and the throttle wall that are displaced in accordance with pressure fluctuations in the pressure chamber, and the pressure chamber is Since high-pressure lubricant is supplied to the pressure chamber, when the pressure in the pressure chamber becomes high, the variable throttle flow path expands and a high-pressure lubricant train flows into the pressure chamber, thereby preventing displacement of the single rotation shaft.

[Brief explanation of the drawing]

Fig. 1 is a conceptual diagram showing the schematic structure of a conventional static pressure bearing (41I), and Fig. 2 is a conceptual diagram showing the schematic structure of an embodiment of the static pressure bearing according to the present invention. is the axis of rotation. 12 is the bearing body. 13a-13c are pressure chambers. 15 is the casing. Rooms 16a-i6c are. F is Diamond Slam. 18 is a large number of walls. 19a-19c are partition rooms. 20 is a high pressure lubricant supply device. 22 is a variable throttle multi-channel. 23 is a lubricant supply hole. Patent applicant Mitsubishi Heavy Industries, Ltd.

Claims (1)

[Claims] Three partition systems each comprising a radial diaphragm that partitions a sealed casing into three equal chambers, and a diaphragm υ wall formed in each of the three chambers in a sealed state and facing the diaphragm in close proximity. a chamber, a high-pressure lubricant supply source that supplies high-pressure lubricant into each of these three partitioned chambers, and a chamber formed at equal intervals on the inner circumferential wall of the bearing body through which the one-rotation shaft passes, and which is outside the partitioned multi-chamber; three pressure chambers each communicating one-to-one within the diaphragm and the diaphragm and the diaphragm wall, each of which is perforated in the diaphragm wall of the partition chamber and communicating between the inside and outside of the partition chamber; A hydrostatic bearing comprising a lubricant supply hole forming a variable restriction flow path for the lubricant between the lubricant supply holes.