WO2001027483A1

WO2001027483A1 - A slide bearing or slide sealing device

Info

Publication number: WO2001027483A1
Application number: PCT/NO2000/000321
Authority: WO
Inventors: Kristian TÖNDER
Original assignee: Toender Kristian
Priority date: 1999-10-08
Filing date: 2000-10-02
Publication date: 2001-04-19
Also published as: NO994938L; AU7817800A; NO994938D0; NO310484B1

Abstract

A slide bearing or a sealing device, wherein two adjacent and preferably level and/or parallel surfaces slide against each other upon supply of a thin layer of lubricating fluid. At the edge of at least one part of said slide bearing or sealing device, an inlet area (14) for the lubricating layer is provided with as a roughness (14) relatively to the adjoining slit area (13), this expansion being provided as roughness (14) of at least one of the two surfaces (11, 12).

Description

A slide bearing or slide sealing device.

The invention is related to a slide bearing or slide sealing device, in which two adjacent and preferably level surfaces slide against each other under supply of a layer of lubricating fluid, particularly lube oil, or air or another gas, as stated in the introductory part of claim 1.

Bearings of this type exist in different types of machines, such as turbines having thrust bearings, and as sealings for pistons in combustion engines. These elements also exist in applications where the prior art has been unable to supply a common lubricant, such as read heads and recording heads in computers, in which thin movable parts are running in air.

Background

When dividing two independently moving surfaces with a fluid lubricant or another fluid layer, such as a lube oil layer, it is desirable to form a hydrodynamic pressure. This pressure rising from the inlet end towards a central section to a maximum value and then decreasing towards the outlet end. The ideal condition is formation of a thin fluid layer at high pressure.

Special leading surfaces and similar have been formed at the inlet edge to obtain increased lubricating effect, but such approaches have not provided satisfactory results, particularly because the hydrodynamic pressure has been too low when the layer of lubricating fluid becomes too thin.

Object

The main object of the invention is to form bearings and sealings for the situations described, that ensure a best possible lubrication. The object is to reduce the friction with a lowest possible consumption of lubricating fluid. In other situations, it is also an object to remove or at least reduce the wear.

There is a special case in numerous types of electronic equipment wherein small prior art bearings and sealings are lubricated by air. This is particularly the case with hard disks for computer equipment. In this connection, an object of the invention is to adapt the invention to increase the lifetime and reduce the risk of breakdown. Invention

The invention is stated in claim 1 This will provide a substantial improvment to bearings and sealings provided with gradation and other forms of bearing profiles as a means to improve pressure formation in a supplied lubricating fluid We have expeπenced that the roughemng of an inlet zone will reduce the flow resistance for lubricant in this zone Accordingly, the lubricating layer can be made thinner and the pressure establishment increases and becomes more stable

It is assumed that the invention is based upon the roughening which facilitates lubricant entrance into the component parts, such as beanng parts and sealing parts Then, the lubricant is forced into a thinner area at increased pressure which produces a lubricating effect

The invention can be combined with the forming of a tapered, sloping or rounded mlet edge, as stated in claim 2

Numerous details of the invention, including dimension information, is apparent from the following example

The device in accordance with the invention is easy to produce The device is particularly effectπve with very thm lubncatmg layers The lubncant can be supplied externally, or the bearing or sealing can be operated within a bath of lubricating fluid

Example

The invention is illustrated in the drawings, wherein

Fig 1 illustrates a schematic section through two component parts forming a beanng and which move independently in parallel having a lubncatmg layer therebetween, and Fig 2 illustrates a section of a piston nng in a combustion engine

Figure 1 illustrates a lower component part 11 having a level surface serving as support for a supenmposed component part 12 having an equivalent level underside, wherein said two parts 1 1 and 12 are to be moved independently in parallel or substantially in parallel with the sht opening 13 established therebetween However, the invention is not limited to such a honzontal slit orientation or to level surfaces, since the invention also can be used upon cylindrical surfaces and other surfaces moving with a slit shaped interstice, wherein the interstice is supplied with a friction reducing medium, particularly lube oil At the mlet of the sht opening 13, the edge region of the superimposed component part 12 is provided with a roughened mlet area 14 The term "roughening" is meant to descnbe a surface structure exhibiting a pattern or a randomly shaped surface of praks, in which the distance from one peak to another is small A pattern is not essential required and the roughening can be differentiated in the sense of depth, and the shape may vary from one region to another. The mam purpose of this construction is to form a gradual transition to increase the resistance to entrance of lubncatmg fluid

The roughened area could extend for fractions of a millimetre to several centimeters from the edge area, dependent on the beanng dimension and the application field The depth of the roughening can range from the nanometer level for tiny air beanngs, to 1/10 millimeters for large thrust beanngs

The roughening can be provided in the form of elongate, transverse or diagonal grooves The individual groove can be straight, sinuously shaped or have some other curvature, primarily with a structure forming parallel grooves The roughening pattern can also be composed by several elements, or may lack systematics

Some forms of beanngs and sealing devices according to the invention may exhibit slots or grooves having a decreasing depth from the edge, possibly passing into a number of transversly extending grooves, for example with a uniform shape

The roughness can be provided mechanically, such as machining or sandblasting, or electrochemically, such as by electrolysis, or chemically, such as etching It is also conceivable that a component part in an appropriate manner is coated by a layer having a roughened edge section

The optimization of the roughening method and roughness degree has not been determined This is dependent on the size and operating conditions of the bearing and the matenals used The roughness expressed as groove depth can be of a similar magnitude as the desired thickness of the lubricating layer

The invention is applicable to different types of beanngs, from large mechanical constructions, such as turbine beanngs, to tmy beanngs, such as equipment for data storage in which the pnor art apply air lubncated beanngs The mam purpose in this connection is the attainment of a thinner layer of lubricating fluid, I e air, and stiffness and damping of the support The invention is also applicable to sealing constructions. An example of this application is provided in Fig. 2, which illustrates a section of a piston 15 in a combustion engine having a groove 16 for a piston ring 17 which is travelling up and down in the figure in contact with the cylinder wall 22. Lubricating oil is supplied from the interior of the piston through an aperture (not illustrated) and into the groove 16. Alternatively, the lubricating oil can be supplied through a groove having special oil rings. In this way the lubricating oil will arrive at the piston ring 17 on both sides of the same and is presumed to penetrate the area between the piston ring and the cylinder wall to provide a lubricating effect when sealing. The invention is applicable to sealing devices of different types, such as lip sealings, flange sealings and movable sealing rings for applications other than piston sealings.

An upper roughness 19 and a lower roughness 20 is formed at the edges of the piston ring 17. The extension of the two rougnened areas 19 and 20 can constitute about 1/4 of the width of the piston ring, each. In this way, every piston movement wil provide formation of a lubricant stratum at increased pressure in accordance with the invention. The maximum hydrostatic oil pressure will appear at the center of the piston ring, wherein the example offers at least one half ring width 21 to form an active bearing surface to the cylinder wall 22.

The limits of the extension of the roughness areas and the relation between the roughened areas and the remaining areas has not been explored. However, it is assumed that these parameters may vay within wide limits, dependent on the application and the desired effect.

Claims

Claims.

1. A slide bearing or sealing device, wherein two adjacent and preferably level and/or parallel surfaces slide against each other upon supply of a thin layer of lubricating fluid, particularly lube oil or air to an interstice between the surfacees, and at the edge of one part of said slide bearing or sealing device there is arranged means to provide increased supply of lubricant, characterized in that the surface area of an inlet (14) for the lubricating layer is expanded in and the expanded area is provided as roughness (14) of at least one of the two surfaces (11,12).

2. Device in accordance with claim 1. characterized in that the roughness is combined with an edge gradation, edge roundness or edge sloping in order to increase the supply of lubricating medium to the interstice.

3. Device in accordance with claim 1 or 2, ch a racterized in that the roughness (14) is provided in the form of grooves extending alternating linearly or wavy transversely to the direction of motion, or unsystematic.

4. Device in accordance with claim 3, characterized in that the roughness is differentiated.

5. Device in accordance with claim 4, characterized in that the roughness is provided as grooves extending inwards with a decreasing depth from the edge of the bearing surface, then possibly changing into transversely extending grooves and similar.

6. Device in accordance with any one of claims 1 to 3, characterized in that the roughness expressed as groove depth is within the same magnitude as the desired thickness of the lubricant layer.

7. Device in accordance with any one of claims 1 to 6, applied to a piston ring (17) for a combustion engine or a similar sealing construction, characterized in that the roughness (19,20) is located at the upper edge and at the lower edge of the piston ring perionera 1 surface.

8. Device in accordance with claim 7, characterized in that the roughness (19,20) constitutes a maximum of about 1/4 of the piston ring (17) height, respectively.