DD280149A1 - SELF-LUBRICATING SINTERED SLIDING BEARINGS WITH ZONES OF DIFFERENT PERMEABILITAET - Google Patents

Abstract

The invention relates to a self-lubricating sintered sliding bearing with zones of different permeability. The aim of the invention is to find a self-lubricating sintered sliding bearing with zones of different permeability to increase the lubricity of the introduced lubricant and the Tragfaehigkeit in certain areas. According to the invention, the object is achieved in that the sintered sliding bearing consists of a material that is compressed differently in at least one area. In this case, the higher-density area, viewed over the circumference, is characterized by a continuous transition to the less compacted area. For Permeabilitaetsaenderung no additional materials are used and the bearing body has a constant density in the radial direction. Fig. 1

Description

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Field of application of the invention

The invention relates to a self-lubricating sintered sliding bearing with zones of different permeability

 Fields of application of the invention are all areas in which sintered plain bearings are used in order to ensure a high level of maintenance-free apparatus-technical assemblies. Examples are the precision engineering, medical technology, consumer electronics and similar.

Characteristic of the known state of the art

It is known that conventionally sintered self-lubricating bearings of the same density are currently used in the radial and axial directions and the bearing is protected with regions of induced permeability on the inner surface of the bearing. Furthermore, there are sintered plain bearings with increased working capacity based on the use of a arranged behind the sintered sliding gas chamber. The latter camp requires an increased production cost. Conventionally sintered plain bearings have typical application limits with regard to speed and load limits. The bearing with reduced permeability on the inner bearing surface has radially outlined and circumferentially defined areas with a smaller permeability than the mean permeability of the bearing itself. Part ¹ was to allow the bearing to operate under significantly higher load conditions than conventional ones sintered, self-lubricating bearings. For this purpose, additional elements (according to Fig. 2 Patent DE 2920522 A1 platelets, etc.) can be used

 Self-lubricating sintered plain bearings must therefore:

- ensure a high load capacity,

- have sufficient lubrication,

- have a low production cost and

- be maintenance free.

Object of the invention

The aim of the invention is a Fartigungsmäßig relatively easy to produce selbstschmierendos sintered plain bearings, that

- aa guaranteed increased capacity over conventional sintered bearings.

- The drain of the lubricant from the loading zone is reduced, which is due to the loaded shaft against the bushing.

- Having an improved lubricant circuit, due to the utilization of the concentration equalization law between higher and lower compressed areas of the bearing has.

Freedom guaranteed by the use of a lubricant impregnated sintered material as a bearing material.

Explanation of the essence of the invention

The invention has for its object to provide a cost-effective self-lubricating sintered plain bearing with increased load capacity and improved lubricant circulation. The property of conventional sintered bearings is not limited in terms of freedom from maintenance.

According to the invention the object is achieved in that zones are created with different permeability, so that the bearing hesteht of a material which is compressed differently in at least one area

 According to the present invention, it is provided to provide the self-lubricating sintered plain bearing in the radial bearing cross section with zones (at least 1) of different density, while a constant DurchlässigriOitswert may be present in relation to the remaining area on the bearing inner surface. The higher density area, when properly installed, will provide greater bearing capacity than conventionally sintered bearings. The steady transition to the less densified area ensures gradual lubrication balance between the areas and ensures the presence of sufficient lubricant in the sintered plain bearing. Due to the use of a starting material, no additional elements for increasing the bearing capacity, permeability change, etc., are necessary.

The number of areas of different density can be different (at least 1) and depend on the operating conditions, such as:

- Constancy or non-constancy of the debit position

- Constancy or non-constancy of the direction of rotation

Constancy or non-constancy of peripheral speed

- Wall thickness of the bearing

- Possibility of mounting the bearing in the seat with a fixed positioning with respect to the effect level de load.

The areas of different density allow that in the range of maximum pressure, a lubricating film between shaft 5 and bearing 6 forms, which adjusts to the load conditions.

embodiment

Fig. 1 shows a radial bearing cross section through the self-lubricating sintered plain bearing, in which the higher-density region 4 is punctured more dense than the less compressed region 3. The continuous transition is shown in FIG. 1 by a different degrees of puncturing the radial bearing cross-section. The line of action of load 1 is indicated by the arrow. The arrows 2 represent the oil flow direction. According to the invention, penetration of the oil into the porous mass of the region 4 is impeded or prevented, whereby the formation of a continuous lubricant film between the sleeve 6 and shaft 5 is made possible. At the same time, the lubricant supply is improved by the erfc Igend concentration equalization between the differently compressed areas. In the loading zone, the load capacity of the bushing 6, compared to conventionally sintered sintered plain bearings, is increased by means of material of higher densities. The sintered materials which are suitable for the realization of the bearings of the type according to the invention are:

- iron and its alloys

- Steel of any composition, including stainless steels

- Copper alloys

- Aluminum, zinc and their alloys.

On the whole, the necessary manufacturing method does not differ significantly from the method commonly used in powder metallurgy, with the following steps:

1. Pressing the metal powder with a suitably shaped core that an internal profile of the bearing is realized, depending on the geometric properties of the bearing and the different operating conditions.

2. sintering under the material specific conditions.

3. Press smoothing in a mold with annular and circular elements.

4. Impregnation with lubricating oil selected on the basis of the operation and design specification. The impregnation process can also be successful before press-smoothing.

To produce the sintered plain bearing according to the invention, the pressing tools can be changed to the effect that

- Matrizenplatte and die have a partial recess (flattening), which allows a different filling height of the bearing to be pressed in the axial direction and ensures a smooth, trouble-free sweeping the Füllschuhes.

- The filling shoe is formed so that upon retraction of the same, the different filling of the die is maintained. Starting from a different filling level of the bearing to be pressed in the pressed bearing with a uniform length thereby higher and lower density areas are generated without affecting the pressing technology.

Claims (4)

1. Self-lubricating sintered plain bearing with zones of different permeability, characterized
in that the bearing consists of a material which is in at least one area
is compressed differently. 2. Self-lubricating sintered plain bearing according to claim 1, characterized in that in the radial
Bearing cross section areas of different density are present. 3. Self-lubricating sintered plain bearing according to claim 1 and 2, characterized in that zones of different density are formed on the inner bearing circumference, the continuous one another
go over and the density in the radial direction is constant. 4. Self-lubricating sintered plain bearing according to claim 1, characterized in that the low-density region with its lowest value 40 to 80% of the density of the rest of the bearing.