WO1987005674A1 - Sliding element, in particular a sliding bearing, with an inhomogeneous antifriction layer - Google Patents

Abstract

To improve a sliding element, in particular a sliding bearing, with an inhomogeneous antifriction layer, consisting of a support layer (32) and a sliding bearing material layer (27) applied to the support layer and provided with groove-like recesses arranged at a distance from one another and extending at least over part of the sliding surface and filled with another sliding bearing material (30) (filler material), optimal dimensioning of the groove-like recesses (26), specific to the relevant bearing loading is achieved in respect of width, depth and distance, taking into account the relevant sliding material of the bearing and the material in the groove-like recesses (filler material).

Description

 Sliding element, in particular plain bearing, with an inhomogeneous anti-friction layer

The invention relates to a sliding element, in particular a sliding bearing, with an inhomogeneous antifriction layer, consisting of a support layer and a support layer made of a slide bearing material, which is arranged on the support layer and which is spaced apart from one another and distributed at least over part of the circumference another plain bearing material (filler) has filled groove-like depressions, the plain bearing material of the base layer and the plain bearing material filling the groove-like depressions having different hardnesses, in particular the invention relates to radial plain bearings with at least part of the circumference, with a slide ¬ bearing material filled groove-like depressions in the base layer.

From AU-PS 143 992, in particular its FIG. 5 and the associated parts of the description, a plain bearing with an inhomogeneous anti-friction layer is known, specifically with a spiral groove arrangement extending in the circumferential direction of the plain bearing. These grooves are filled with a soft plain bearing material, which has only a low load-bearing capacity but good rubbing properties. The dimensioning of the grooves should be adapted to the different operating conditions in accordance with AU-PS 143 992. However, no information is given about the actual adaptation to the operating conditions. From AT-PS 323476 an antifriction element, in particular a slide bearing, is known which is formed as a monolithic press part, in which the construction polymers of the type, which are filled with rigid lubricants of the type such as graphite, boron nitride, molybdenum sulfide, individually or in a mixture of these substances, alternate Phenolic resins, polyesters, polyheteroarylenes, polyolefins, polyphenyls or the like. Materials existing self-lubricating plastic sections are arranged. AT-PS 323476 also does not provide any information about the dimensioning of the depressions in the base layer filled with solid lubricant.

Furthermore, it is known from EP-PS 57808 to embed a softer bearing material in groove-like depressions of a harder bearing material layer which extend essentially in the running direction in order to combine the advantages of a harder bearing material with the advantages of softer plain bearing materials

To connect plain bearings. Since the spacing of adjacent recesses ensures a fine distribution of the harder and softer bearing material over the tread width, the individual bearing materials come into effect not only in their own right but also in their combination in a local load area, so that the disadvantages of individual separate bearing materials are essentially turned off. The bearing material layer made of a harder material assumes a load-bearing function which relieves the softer material relatively, which results in an increase in the fatigue strength and wear resistance. With regard to the emergency running behavior, such plain bearings therefore behave largely like bearings with a continuous sliding layer made of a softer bearing material, but have the advantage of significantly lower wear compared to such latter bearings. The plain bearing known from EP-PS 57808 is therefore intended to provide favorable operating results with regard to wear and fatigue, because the groove dimensions such as width, depth and distance are determined in a specific manner depending on the bearing diameter. Practice has shown, however, that the extremely wide spacing of the maximum and minimum ranges of the groove dimensions does not give an optimal distribution of the soft and hard bearing components even in middle areas. Bearings of this embodiment are therefore not suitable for meeting the high demands placed on and expected of them, since other important criteria have been neglected. For example, it was disregarded that bearings with a certain diameter can be subjected to completely different loads and that the bearing diameter as a reference variable alone is therefore in no way suitable for defining measures to reduce wear and fatigue in a manner that is sufficient for practical use.

The object of the invention is therefore to create a heavy-duty plain bearing with an inhomogeneous antifriction layer, which fully meets the requirements to be placed on a heavy-duty plain bearing and thereby creates the possibility of taking the measures to be used for reducing wear and fatigue due to the im The specific bearing load provided for each case must be clearly and reproducibly defined beforehand.

This object is achieved according to the invention by the features contained in the characterizing part of claim 1. The measures listed in the characterizing part of claim 1 are no longer related to the bearing diameter, but to the specific bearing load, which results as follows: p = specific bearing load in N / mm

FP ⁼ D ^~ T

F = bearing force (load) in N_ ^'

D = nominal bearing diameter in 'mπr (inner diameter) B = bearing width in nm With the specific bearing load p used in accordance with the invention to determine the dimensioning of the depressions, the lubricating film pressure in the plain bearing also becomes decisive for the dimensioning of the groove-like depressions filled with other plain bearing material. In the context of the invention it has been shown that the level of the specific loads has a considerable influence on the specifications for the groove-like depressions. This applies on the one hand to the envisaged specific loading of the slide bearing and on the other hand also with regard to the specific resilience of the plain bearing material chosen naturally in accordance with the intended use _, for the base layer and the plain bearing material likewise chosen from such points of view for filling the groove-like depressions . In a particularly advantageous development of the invention, mathematical relationships for the determination of the width b of the groove-like depressions, the web width s remaining between the groove-like depressions, the ratio of the groove width b to the web width s due to the resilience of the selected slide can thus be achieved - Set up the bearing material for the base layer and the specific bearing load actually provided. Likewise, mathematical relationships for the groove t of the depressions and for the ratio of the groove width b and the groove depth t of the groove-like depressions depending on the load capacity of the plain bearing material (filler) chosen to fill the groove-like depressions and the specific bearing load actually provided set up.

The invention can be used both in the case of a simple groove-like design of the depressions extending in the running direction and in the formation of the depressions in a plurality of groups, for example two intersecting groups of groove-like depressions, even when the mutual spacings of the groove-like depressions Specializations in the different groups should be different from each other. Experiments have shown that when the intended specific bearing load is taken into account according to the invention when dimensioning the groove-shaped depressions, optimum results are achieved with regard to fatigue strength, wear and emergency operation.

Embodiments of the invention are explained in more detail below with reference to the drawing. Show it:

1 is a perspective view of a slide bearing according to the invention formed from two slide bearing shells;

2 shows a plain bearing according to the invention in the form of a bearing bush;

3 shows a diagram with the parameters which are essential for calculating the area of the bearing sliding surface provided with depressions;

4 shows the area 5 of FIG. 1, greatly enlarged;

5 the area 5 of FIG. 1 in a modified version, greatly enlarged;

6 shows a greatly enlarged top view in area 6 of FIG. 1;

7 shows a plan view corresponding to FIG. 6 in a modified embodiment of the invention;

8 shows a plan view corresponding to FIG. 6 in a further modification of the invention; 9 shows a one-piece flange bearing shell designed according to the invention; and

10 is a perspective view of a bearing shell and two semi-annular thrust washers for a bearing arrangement according to the invention; In the example of FIGS. 1 to 8, a sliding bearing 20, for example in the form of two bearing shells 21 and 22 or in the form of a sliding bearing bush 23, which can be seamless or also curved and formed with an axial slot 24, is on the bearing sliding surface 25 provided with groove-like depressions 26 in the base layer 27. The central bearing axis is designated 28.

In the example in FIG. 1, the slide bearing 20 is formed from two slide bearing shells 21 and 22 which have groove-like depressions 26 in their base layer 27.

Various embodiments are possible for the groove-like depressions 26, for example grooves running in a circular manner, as shown in a top view in FIG. The groove-like depressions 26 could also be helical with a small pitch angle of up to 15. Between the groove-like depressions 26 and the webs 29 which have remained between them, the following parameters are essential, as can be seen particularly from FIG. 3:

a: The distance from the center of the web to the center of the web; b: the recess width in the area of the sliding surface; s: the remaining web width in the area of the sliding surface; t: the recess depth.

Of the ratios derived from these parameters, the relation of the recess width b to the remaining web width s is particularly important. For the calculation of these parameters and the relation of recess width b to the remaining web width, minimum values, maximum values and mean values have to be determined on the basis of the specific bearing load p, whereby

p - jrN / mm2 ^"1 | is to be calculated from F = bearing force (load) in 'N, D = nominal bearing diameter in [mm] (inner diameter)

B = load bearing width in ^r mm. according to the formula: F ^"

On this basis, the following are to be calculated: a) width b in μm of the groove-like depressions or recesses 26; for heavy-duty base layers, i.e. Base layers with a load capacity above about 50 N / mm based on the projected storage area, equal or smaller, but preferably

max = 200 20 p + 12.5 for lightly bearing base layers, i.e. Base layers with

2 Load capacity below about 35 N / mm, based on the projected storage area, equal or greater, but preferably b mm. = 56, 25 20 'p + 12, 5 for medium-duty base layers, i.e. Base layers with

2 Load capacity between about 30 and about 55 N / mm, based on the projected storage area, smaller or larger, preferred

b) the remaining web width s in μm: for lightly bearing base layers, i.e. Base layers with

2 Resilience below about 35 N / mm, based on the projected storage area, the same or smaller, but preferably

for heavy-duty base layers, i.e. Base layers with

2 2 llaassttbbaarrkkeeiitt oobbeerrhhaallbb eettwwaa 5500 NN // mmmm ,, bbeezzooggeenn on the projected

Storage area, equal or larger, but preferred

für mittelbelastbare Tragschichten, d.h. Tragschichten mit

for medium-load base layers, ie base layers with

2 Resilience between about 30 and about 55 N / mm, based on the projected storage area, smaller or larger, but preferably

c) The recess depth t in [L_μτm- ^" for heavy-duty fillers, ie plain bearing materials with

2 Resilience above about 40 N / mm, based on the projected storage area, equal or less, but preferably t 1350 max

12.5 for low-load fillers, i.e. Plain bearing materials

2 with a load capacity below about 20 N / mm, based on the projected bearing surface, equal or greater, _but preferably t. , - ⁹⁰⁰ min - _.- _r p + 12.5 for medium-duty fillers, ie plain bearing materials

2 with a load capacity of between approximately 20 and approximately 45 N / mm, surface area, smaller or larger

d) the relation of recess width b to remaining web width s: for heavy-duty base layers, i.e. Base layers with loading

2 llaassttbbaarrkkeeiitt (above about 50 N / mm, based on the projected storage area,

(b / s) = (1.95 to 2.0). (1.757 + 3.1- 1θ ^"3 -p + 7.233- 10 ^-4 -p ² )

for lightly bearing base layers, i.e. Base layers with

2 resilience below about 35 N / mm, based on the projected storage area,

(b / s) _min = (0.5 to 0.55). (0.5100 + 0.9-1θ ^"3 -p + 2, MO ^_ -p ² ) for medium-load base layers, ie base layers with

2 load capacity between about 30 and about 55 N / mm, based on the projected storage area,

(b / s) _with = 0.9444 + 1.6667-10 ^"3 .p + 3.8889-10 ^{" 4} -p ²

and the dependence of the selected recess width (b) in relation to the recess depth (t) for heavy-duty fillers, i.e. Plain bearing materials with a load capacity above

2 of about 40 N / mm, based on the projected storage area,

(b / t). _^ = 4.167 -10 ~ ² -p + 0.8333 for low loadable fillers, ie plain bearing materials with

2 BBeellaassttbbaarrkkeeiitt uunntteerhund of about 20 N / mm, based on the projected storage area,

(b / t) _αv = 10.834-10 ^-2 .p + 2.1666 for medium-duty fillers, ie plain bearing materials with

2 load capacity between about 20 and about 45 N / mm, based on the projected storage area,

(b / t) _with = 6.667-10 ^"2 .p + 1.333 must be fulfilled

_ 2 where p = specific bearing load in N / mm

P = D-B

It is taken into account here that not only the bearing diameter, but above all the lubricating film pressure, is decisive for the dimensioning of the groove-shaped depressions, for example of such a plain bearing. In simple terms, the specific bearing load can be used instead of the lubricating film pressure. It has been shown that at high specific loads other definitions of the relevant sizes for the groove-shaped recesses (width, depth, distance) are more advantageous than at low specific loads. In particular, it has a surprising effect in connection with the selection of the Plain bearing material for the carrier layer and the filler in the groove-like depressions on the design of the recesses in width and depth. In this way, the fatigue strength and wear resistance of a plain bearing can be optimally influenced. The use of different materials for the carrier layer and different fillers accordingly requires different dimensions of the depressions. The above explanations contain information on how these material properties are to be taken into account.

Tests have shown that, taking into account the dimensioning of the groove-like depressions explained above, optimum results are achieved with regard to fatigue strength, wear and emergency running.

The groove-like depressions can form closed annular grooves, but it is preferred to provide annular depressions in a helical arrangement.

As can be seen from the region 5 of FIG. 1 shown in a greatly enlarged form in FIG. 5, the slide bearing material filling the groove-like depressions 26 can be formed beyond the remaining ribs or fields 29 to form a closed layer 30. Depending on the slide bearing materials used for the base layer 27 and the material filling the groove-like recesses 26 and possibly forming the sliding layer 30, a diffusion barrier layer or a binding layer 31 can be provided between the base layer 27 and the material filling the groove-like recesses 26 and possibly forming the sliding layer 30 be provided, which can have a thickness between about 0.5 and 2 microns. In contrast to this, FIG. 4 alternatively shows in the enlarged area 4 of FIG. 1 a flush termination of the ribs 29 with the sliding layer 30 or the filling of the groove-like depressions 26. - -11 -

As FIGS. 4 and 5 also show, the support layer 27 is attached to a suitable substrate 32, for example a shell or bush made of steel.

The shape of the groove-like depressions can be different, for example the groove-like depressions 26 can be designed in the manner of a cross thread, so that between the groove-like depressions 26 there are diamond-shaped or otherwise square fields 29, as shown in FIG. 7. In addition to a cross thread, the groove-like depressions 26 can also have transversely extending grooves 26a, so that triangular, remaining fields 29 result, as shown in FIG. The mutual distances between the intersecting groove-like depressions 26 are shown in Figures 7 and 8 as the same size. However, a mutual groove spacing can also be provided in one group of depressions 26 than in the group of depressions 26 crossing them.

FIG. 9 shows a flange bearing shell 22a, which in its radial bearing part contains a bearing sliding surface 25 with groove-like depressions 26 in the base layer 27. One collar 35 is formed on its base layer 27 with groove-like depressions 26 which, in this example, have a spiral shape, that is to say they widen in the initial direction. In this example, the groove-like depressions 26 could also be formed concentrically to the central position axis. As with the radial bearing part, the groove-like recesses 26 in the collar 35 are also filled with plain bearing material, this bearing material also being able to cover the ribs or fields arranged between the groove-like recesses. The second collar 36 of the collar bearing shell 22 according to FIG. 9 can be designed like the first collar or in a conventional manner with a smooth surface of its base layer. To form a complete plain bearing a flange bearing shell according to FIG. 9 is assembled with a second flange bearing shell, which can be designed in the same way as that according to FIG. 9 or in a conventional manner.

The same or similar design as in a one-piece flange bearing 22a can also be provided in those plain bearings in which the collars are designed as separate thrust washers 38 and 39 and are attached directly to the radial bearing part by means of connecting straps.

The example in FIG. 10 is a bearing arrangement in which the radial bearing part is formed by two plain bearing shells 21 and 22 (FIG. 1). The slide bearing shell 22 has a bearing sliding surface 25, in which the base layer is provided with groove-like depressions 26. Axial bearing parts are used without contact to this radial bearing part, namely thrust washers 38 and 39, which are inserted into the bearing receptacle at a lateral distance from the side edges of the radial bearing part. One thrust washer 38 or both thrust washers 38 and 39 have groove-like depressions in their base layer, which are concentric with the center axis of the bearing. Instead, spiral-like groove-like depressions could also be provided.

In all of the exemplary embodiments described above, the most varied combinations of slide bearing materials are possible, for example the base layer 27 can consist of lead bronze. The slide bearing material filling the groove-like depressions 26 can be white metal bearing alloy, preferably a tin-antimony alloy of the SnSb7 type can be used for this purpose. Instead of the sliding layer 30 shown in FIG. 4, it is also possible to cover the remaining ribs or fields 29 with a covering , - -

Layer made of lead-tin alloy or tin-antimony alloy with a thickness of 0.5 to 2 microns.

Another advantageous material pairing in a plain bearing shell 22 or a plain bearing bush 23 can consist, for example, in that the supporting layer 27 consists of an aluminum alloy, preferably AlZn4, 5SiCuPbMg, and the groove-like depressions are preferably filled with a white metal plain bearing alloy based on PbSnCu. In such a case, a layer 31 made of nickel or CuSn will have to be provided.

Claims

Sliding element, in particular plain bearing, with an inhomogeneous antifriction layer P a t e n t a n s r u c h e 1) sliding element, in particular sliding bearing, with an inhomogeneous anti-friction layer, consisting of a supporting layer and a supporting layer made of a sliding bearing material, which is applied to the supporting layer and which is spaced from one another, essentially 5 arranged in parallel, distributed at least over part of the sliding surface another plain bearing material (filler) has filled groove-like depressions, the plain bearing material of the base layer and the plain bearing material filling the depressions differing in hardness from one another 10 have, for example, radial slide bearings with recesses in the base layer which extend in the circumferential direction at an axial distance from one another and are filled with slide bearing material, characterized in that the groove width b of the recesses and the web width s and 15 the ratio of groove width b and web width s together with the load capacity of the bearing material selected for the base layer, as well as the groove depth t and the ratio of the groove width b to the groove depth t together with the load capacity of the for the filling of the depressions chosen slide bearing material are matched to the specific bearing load p provided for the slide element. 2) Sliding element according to claim 1, characterized by the coordination of groove width b and web width s and the ratio of groove width b and web width s to the specific bearing load p provided for the sliding element for heavy-duty base layers, i.e. Base layers with resilience 2 from above about 50 N / mm, based on the projected bearing surface, in the following way: a) groove width b rμmi equal or smaller, but preferably

b) The remaining web width s in 'μm is equal or greater, but is preferred

c) The ratio of the width b of the depressions to the remaining web width s (b / s) = (1.95 to 2.0) - (1.757 + 3.1-10 ^{~ 3} -p + 7.233'10 ~ ⁴ -p ² ). 3) sliding element according to claim 1, characterized by the coordination of groove width b and web width s and the ratio of groove width b and web width s to the specific bearing load p provided for the sliding element for lightly loadable base layers, i.e. Base layers with resilience 2 half of about 35 N / mm, based on the projected bearing surface, in the following manner: a) Width b of the groove-like depressions in fμm ¹ equal or greater, but preferably _b . = £ 56.25 - ^ ^m p + 12.5 b) Remaining web width s in fμ l equal or smaller, but preferred

c) The ratio of groove width b to remaining web width s (b / s). = (0.5 to 0.55) - (0.5100 + 0.9-1θ ^"3 -p + 2.1 • 10 ^{~ 4} .p ² - ¹ 4) Sliding element according to claim 1 characterized by the coordination of groove width b and web width s and the ratio of groove width b and web width s to the specific bearing load p provided for the sliding element for medium-load bearing layers, i.e. Base layers with resilience between 2 about 30 and about 55 N / mm, based on the projected bearing surface, in the following way: a) width b in ^r μm _. the groove-like depressions smaller or larger, but preferably b - = 75 it-2 ° ^with p + 12.5 b) The remaining web width s in ^'.mu.m smaller or larger, but preferably

c) The ratio of groove width b to remaining web width s ^(b / ^s) with ⁼ °> ^{9444 +} 1.6667-10 ^"3 -p + 3 + 3.8889-10 ^_ -p ² 5) sliding element according to one of claims 1 to 4, characterized by the coordination of the groove depth t in ^r microns; of the groove-like depressions and the ratio of the groove width b to the groove depth t of the groove-like depressions for heavy-duty sliding bearing materials filling the depressions, ie sliding 2 bearing materials with a load capacity above about 40 N / mm, in relation to the projected bearing surface, in the following manner d) groove depth t in iμmj equal or less, but preferably t = 1350 ^ma p + 12.5 and e) the ratio of groove width b to groove depth t of the groove-like depressions (b / t) _min = 4.167 -10 ^"2. p + 0.8333. 6) sliding element according to one of claims 1 to 4, characterized by the coordination of the groove depth in [μm! the groove-like depressions and the ratio of the groove width b to the groove depth t of the groove-like depressions for low-load bearing material which fills the groove-like depressions, i.e. 2 plain bearing materials with a load capacity below about 25 N / mm, based on the projected bearing surface, in the following way: d) Groove depth t in ^: μm equal or greater, but preferably _t = 900 min _.- _r jp + 12.5 and e ) the ratio of groove width b to groove depth t of the depressions (b / t) _βv = (1.95 to 2.0). (10.834-10 ~ ^2. p + 2.1666). ax 7) sliding element according to one of claims 1 to 4, characterized by the coordination of the groove depth t in μm of the groove-like Indentations and the ratio of the groove width b to the groove depth t of the groove-like recesses for medium-strength sliding bearing materials filling the groove-like recesses, i.e. Plain bearing materials with a load capacity between about 20 and 2 about 45 N / mm based on the projected bearing surface in the following manner: d) Groove depth t in ^r μm of the depressions smaller or larger, but preferably 1125 with 12.5 and e) the ratio of the groove width b to the groove depth t of the depressions: (b / t) _with = 6.667 • 10 ^"2 • p + 1.333. 8) Sliding element according to one of claims 1 to 7, characterized in that two groups of mutually parallel groove-like depressions are provided, in a mutually intersecting arrangement, the mutual spacing of the groove-like depressions in one Group is different from the mutual distance of the groove-like depressions of the other group. - 19 - Sliding element, in particular plain bearing, with an inhomogeneous anti-friction layer T h e c tio n l i s t e 20 plain bearings 21 plain bearing shell 22 plain bearing shell 22a flange bearing shell 23 plain bearing bush 24 axial slot 25 Camp run 26 groove-like depressions 26a transversely extending grooves 27 base course 28 central bearing axis 29 ribs 30 sliding layer 31 Diffusion barrier layer or tie layer 32 Substrate / support material 35 fret 36 fret 38 thrust washer 39 Thrust washer a spacing between webs b recess width s web side t recess depth