SE469852B - Hydrostatic axial bearing - Google Patents

Abstract

In a hydrostatic axial bearing for a radially mounted shaft 1, use is made of two hydrostatic annular chamber bearings 4, 5 which act axially in mutually opposite directions and act against one or two flanges or pressure plates 2, 3 connected to the shaft. The hydrostatic bearings are axially movable and directly mechanically interconnected, together forming a double- sided hydrostatic axial bearing. This axial bearing then constitutes the piston in a linear hydraulic motor with pressure chambers A, B. In order to maintain the desired axial position of the shaft, a hydraulic control valve 11 is adapted so as to regulate, by means of a member 139 sensing the position of the shaft, the fluid pressure and quantity of each pressure chamber A, B. <IMAGE>

Description

46 10 15 20 25 30 35 9 8 52 2 flanges fixedly mounted on a shaft. The bearings are also axially movable and mounted against the respective pressure plate over each of the pressure chambers. Volume and pressure in its chamber are then regulated by a servo-type hydraulic control valve.

With this control valve, varying axial loads can be accommodated without appreciably affecting the set position of the shaft and also provides the possibility of adjusting said axial position during operation.

A crucial disadvantage of these solutions is that both of the hydrostatic thrust bearings, due to the characteristics of the servo valve, will always be mounted against their pressure plates.

For example, if the valve is supplied with a system pressure of 70 bar and the pressure chambers have a pressure-exposed area of 1000 cmz, the valve will distribute the pressure 70/2 = 35 bar to each chamber in an unloaded state at the shaft, which gives a load corresponding to 35 tons of respective stock. Thus, both hydrostat bearings are loaded with 35 tons each to no avail as the apparatus has no or low axial load.

When an axial load has developed, the valve will increase / decrease the pressure in each chamber in relation to said load, which means that the load on one bearing increases as much as it decreases on the other. But in any case, one of the thrust bearings will always be loaded unnecessarily.

A main object of the invention is to provide a double-acting hydrostatic axial bearing with the same adjustment possibility as the above-mentioned examples but without the disadvantages described. Description of the invention and its preferred embodiments Fig. 1 shows a vertical section of an axial bearing according to the invention.

Fig. 2 also shows a vertical section of an axial bearing according to the invention but with the hydrostatic bearings facing away from each other against their respective pressure plate.

Fig. 3 shows a possible application of the invention integrated in a larger storage system.

In Fig. 1, 1 denotes a radially mounted shaft and 2 a flange or pressure plate connected thereto. The hydrostatic thrust bearings 4,5 are equipped with each one or more fluid pockets 4a, Sa supplied with fluid from the pumps 7, 9 through the lines 7a, 9a. The pumps driven by the motor 10.

The surrounding bearing housing 6 together with the hydrate bearings 4, 5 and its seals 4b, 5b form the pressure chambers A and B, respectively, where said bearings are axially displaceable. The two hydrostat bearings are arranged to be in mechanical contact with each other according to the figure so that together they form a double-sided axial bearing arranged in a linear hydraulic motor with the pressure chambers A and B.

A hydraulic control valve 11 supplied with fluid from a pump 8 regulates pressure and fluid supply to the respective chambers A and B through the lines 11a, 11b. Through a sensor means 13 which senses the axial position of the shaft, the hydraulic control valve is actuated to distribute the fluid pressure to the chambers A, B so that the set axial position on the rotating shaft is maintained independently of axial load.

With the aid of the adjusting device 12, the control valve 11 can be actuated to give the shaft a permanent displacement by changing the reference values of the valve. In this way, the previously described grinding gap in the grinding apparatus 10 can be adjusted during operation.

Thus, when the distance between the bearing surfaces in the double-sided hydrostatic thrust bearing is adapted to be in this context considerably greater than the thickness of the pressure plate, only one bearing surface will always be in contact with the pressure plate regardless of the size and direction of the external load.

For example, as previously described in the unloaded condition and equally large pressure-exposed areas in the chambers A and B, the force on each side becomes equal regardless of system pressure and both bearing surfaces become unloaded.

As a result, as the patent application intended to describe, an axially adjustable double-sided hydrostatic axial bearing is obtained where, in any case, never more than one bearing surface is loaded.

Fig. 2 describes, as previously stated, an axial bearing which is in principle equivalent, with the difference that the bearing surfaces are turned away from each other and that the shaft is equipped with two flanges or pressure plates 2, 3.

Fig. 3 shows a possible application where the axial bearing is applied in an axial and radial bearing unit 16 with spherical roller bearings 14, 15 which do not allow axial displacement of the shaft. Instead, the whole unit constitutes the piston in a linear hydraulic motor with the pressure chambers C, D which hydraulically double-sided both pressure chambers A, B.

Thus arranged to take up all or part of the axial load applied to the bearing unit by the double-sided hydrostatic thrust bearing, since the pressure difference between the chambers C, D of the hydraulic motor corresponds to the pressure difference between the thrust bearings chamber A, B.

This application thus does not depart from the idea of the invention, rather the double-sided hydrostatic axial bearing has been given a support or slave function for the axial and radial bearing unit.

Claims (1)

10 15 20 25 30 vL. 6 Patent claims Hydrostatic axial bearing to a radially mounted shaft (1) comprising two axially acting hydrostatic bearings (4, 5), each with at least one fluid pocket (4a, 5a) fed with fluid from an external flow source, preferably a constant flow pump (7, 9), and which act against one or two pressure plates or flanges (2, 3) connected to the shaft (1), characterized in that the hydrostatic bearings are in direct mechanical contact with double-sided hydrostatic thrust bearings constituting the piston in a linear hydraulic motor forming one with pressure chambers (A, B). Axial bearing according to claim 1, characterized in that a hydraulic control valve (11) is arranged to maintain the required hydraulic pressure in the pressure chambers (a and B, respectively) by means of a shaft position sensing means (13) so that the desired axial position of the shaft is kept constant. . Axial bearing according to claim 1, characterized in that said axial bearing constitutes a support bearing in an axial and / or radial bearing unit which is operatively connected to or constitutes a piston in a linear hydraulic motor, the cylinder space of the piston of which is divided into two with respective pressure chambers ( A, B) such communicating subspaces (C, D) that an increase in load of the axial and / or radial bearing unit in either direction is counteracted by the double-sided hydrostatic thrust bearing. v;