WO2005105431A1

WO2005105431A1 - Method for the production of a plain bearing material

Info

Publication number: WO2005105431A1
Application number: PCT/EP2005/004290
Authority: WO
Inventors: Torsten Recktenwald; Peter Wölki
Original assignee: Saint-Gobain Performance Plastics Pampus Gmbh
Priority date: 2004-04-28
Filing date: 2005-04-21
Publication date: 2005-11-10
Also published as: DE102004020899B3

Abstract

The invention relates to a method for producing a plain bearing material (1) from a metallic support (3) and a sliding material (4). According to said method, the metallic support (3) is first coated with a sliding material (4), whereupon the coated carrier (3) is slit and stretched such that a coated stretched grid is obtained that is provided with a plurality of meshes (2).

Description

METHOD FOR PRODUCING A SLIDING BEARING MATERIAL

The invention relates to a method for producing a plain bearing material from a metallic carrier and a sliding material and a plain bearing material produced by this method, and to the use of such a plain bearing material.

Plain bearing materials of the type mentioned, which are usually composed of a layer system consisting of a metallic carrier and a sliding material, usually in the form of a plastic, are used for a wide variety of applications. Among other things, they are suitable for use as a plain bearing bush. These in turn are used in a variety of ways in hinges and bearings of all kinds, especially in the automotive sector. The operation of such plain bearing bushes made of the plain bearing material is maintenance-free, i. H. lubrication of the bearings is not necessary.

In a method known from practice for producing a sliding bearing material, an expanded metal mesh is first produced by slitting a metal sheet as the carrier material and then stretching, the slots made in the material widening. This is then made up of a large number of meshes, ie openings, each of which is surrounded by material webs. The Expanded mesh is then coated with a sliding material layer made of polytetrafluoroethylene (PTFE). The sliding material layer is applied to the expanded metal as a film or paste, the mesh openings in the expanded metal being completely closed by the applied sliding material layer. A disadvantage of the plain bearing materials produced using the known method, such as are also known, for example, from the published international patent application WO 00/28226, is that the storage properties of the material gradually deteriorate due to abrasion particles that separate from the plain bearing surface during operation of the bearing after worsening, which leads to a reduced life of the plain bearing. Under certain circumstances, abrasion particles can even block the plain bearing. The process itself is uneconomical due to the high material consumption in relation to the sliding material.

The invention is therefore based on the object of specifying a method for producing a plain bearing material which ensures a particularly efficient use of material, wherein plain bearings produced using this method should be distinguished by excellent bearing properties and a long service life.

The object is achieved by a method for producing a sliding bearing material from a metallic carrier and a sliding material, which is characterized by the following method steps: Coating the metallic carrier with a sliding material,

- Slitting the thus coated carrier and

- Stretching the carrier, whereby a coated expanded mesh having a plurality of meshes is obtained.

The method according to the invention is advantageous in several respects. The fact that the process step of the coating, in contrast to the processes known from the prior art, does not take place after, but before the slitting and stretching of the carrier material, considerably reduces the use of sliding material, which leads to a reduction in the production costs. In the case of a plain bearing material produced using the method according to the invention, in contrast to conventionally produced plain bearing materials, the sliding material only covers the webs, while the openings in the mesh remain free. As a result of the slitting and stretching after coating, the effective area of not only the carrier material but also the sliding material layer is increased, so that the specific material use (e.g. measured in g / cm ² ) of the sliding material in comparison to conventionally produced sliding bearing materials sinks. The “effective area” is to be understood here as the overall dimensions of the carrier material after stretching, the areal mesh openings resulting from the stretching contributing to the enlarged total area to a considerable extent. The reduced use of material of the sliding material also contributes to an likewise advantageous weight reduction of the entire warehouse. The storage properties of a plain bearing material produced in the method according to the invention are also superior to those of a plain bearing material produced in a known manner. Thus, in the fact that the mesh openings in the slide bearing material produced according to the invention are not filled with sliding material, the abrasion particles generated during operation can collect in the mesh openings, resulting in a. Reduction of the shear forces caused by the abrasion particles. Consequently, in contrast to conventionally produced plain bearing materials, the sliding properties of the bearing formed from the plain bearing material produced according to the invention are not impaired by the abrasion particles even in long-term operation, which leads to a significant increase in the life of the bearing. In particular, blocking of the bearing is effectively and permanently prevented.

The "open structure" or mesh-like structure of the slide bearing materials produced according to the invention reduces the load-bearing component of the slide bearing, that is to say the surface in sliding contact with the bearing partner, since the sliding material layer only covers the mesh webs. According to the theory, this should lead to increased wear Surprisingly, however, it has been shown that this fundamental disadvantage is far less pronounced in practice than is to be expected in theory, but rather the proportion of wear is increased again by the abrasion particles collecting in the open mesh openings.

Overall, practical tests have been carried out on the slide bearing material produced according to the invention in Surprisingly, it has been shown that increased wear occurs only during commissioning, that is to say when the bearing surfaces “run in”, which quickly drops to a normal value.

Another advantage of the plain bearing material produced by the method according to the invention is that it has increased calibratability. This is due to the particularly good plastic (and elastic) deformability of the sliding layer of the sliding bearing material produced by the method according to the invention, in comparison to plain bearing materials without an open structure. During the calibration process (e.g. with a calibration mandrel) the sliding layer is partially plastically deformed and displaced, whereby the deformed or displaced parts can escape into the open structure. This variability of a plain bearing with an open structure can be increased by the fact that the slotted and stretched plain bearing material is not rolled back to the original thickness, which means that a further deformation of the 3-dimensional expanded metal is still possible during the calibration process. Thus, the calibratability of the plain bearing material can also be controlled by the degree of rolling or calendering.

When the coated carrier material is slit, a three-dimensional structure of the mesh webs is usually produced. This leads to an increase in the thickness of the plain bearing material. Depending on the intended application, the thickness of the plain bearing material must be reduced again. According to an advantageous embodiment of the The inventive method provided that the expanded metal is rolled after stretching. In addition to rolling, the calendering technology known from plastics technology can also be used. Through the subsequent rolling / calendering step, the thickness of the plain bearing material can be adjusted to the desired value in a controlled manner. The plain bearing material is preferably rolled to a thickness of 180 to 80% of the thickness of the coated, not yet slotted metallic carrier.

According to the invention, the metallic carrier is first coated before slitting and stretching. This process step can be carried out using different coating techniques, for example dipping, spraying or knife coating.

It is also possible to coat the metallic carrier by rolling or laminating on a foil. This is usually done by applying a suitable adhesive, in particular a hot melt adhesive, and then rolling or laminating the film on.

According to an advantageous embodiment of the invention, an adhesion promoter layer is applied to the metallic carrier before coating. This can significantly improve the adhesion of the sliding material layer to the metallic carrier. The adhesion promoter layer can be, for example, an organometallic primer, and the surface of the metallic carrier can also be improved with conventional surface treatment methods to improve adhesion Form of chromating, phosphating or sandblasting can be modified before coating.

According to a further embodiment of the invention, it is provided that the coated expanded metal is applied to a further carrier. In procedural terms, this can be done by lamination. The further carrier can be made of steel or stainless steel, for example. If the plain bearing material is shaped, for example, into a plain bearing bush, it can be introduced into a correspondingly dimensioned cylindrical opening in a housing bore. It is also conceivable that one on both sides of a flat metal support

Plain bearing material layer is applied, whereby a sandwich structure is formed. When the plain bearing material, which has just been shaped, is formed, for example, into a plain bearing bush, the improved formability and deep-drawing ability of the plain bearing material produced according to the invention compared to plain bearing materials of the prior art has proven to be a particular advantage.

Depending on the application, it can be advantageous to form the openings of the meshes of the expanded metal with a certain geometry. It is thus possible to produce an expanded metal mesh with trapezoidal, square or round meshes, a circular shape being particularly preferred.

The metallic carrier can be made of different materials. In particular, it is a metal sheet consisting of a material from the group bronze, steel, stainless steel, aluminum, copper, titanium and their alloys formed. Likewise, plated / coated substrates, such as. B. bronze or copper clad steel. As a metal sheet, the metallic support preferably has a thickness of 0.1 to 3 mm, preferably 0.2 to 2 mm.

The plain bearing material produced according to the invention has good tribological properties with low material consumption in particular if the layer of sliding material applied to the metallic carrier by coating has a thickness of 10 μm to 1 mm, preferably 40 μm to 0.5 mm, before the stretching process.

Suitable sliding materials are, in particular, materials which contain a plastic or consist of a polymer compound from the group of high-temperature plastics, the plastic or the polymer preferably being a fluoroplastic, in particular PTFE or PTFE compound, a polyethylene, in particular ultra-high molecular weight polyethylene, is a perfluoroalkoxy polymer, a polyimide, a polyamideimide, a polyether ether ketone and / or a combination thereof.

With regard to the mesh geometry, experimental investigations by the applicant have shown that the following combinations of mesh length, mesh width and web thickness and web width deliver particularly advantageous results with regard to the sliding properties:

In the case of a coarse mesh structure, the mesh length and the mesh width are each 0.2 to 40 mm and the web width and the web thickness are each 0.08 to 15 mm, for a medium mesh structure they are Mesh length and mesh width in each case 1.0 to 15 mm and the web width and web thickness in each case 0.2 to 5 mm and in the case of a fine mesh structure the mesh width in each case 1.5 to 11 mm and the web width and the web thickness in each case 0.25 to 2.5 mm.

Another object of the invention is to provide a plain bearing material which is distinguished by particularly good sliding properties and a service life which is longer than in the prior art.

This object is achieved according to the invention with a plain bearing material according to one of claims 1 to 17. With regard to the advantages of the plain bearing material according to the invention, reference is made to the above.

The invention is also based on the object of specifying a use for such a plain bearing material. This object is achieved by the use of a plain bearing material according to claim 18 as a sliding and reinforcing material in injection molded plain bearings. The injection-molded plain bearings equipped with the plain bearing material according to the invention are distinguished by a reduced coefficient of friction and by improved heat conduction. They also have an improved load behavior, in particular an improved impact load behavior.

The excellent non-stick properties in connection with the gas permeability due to the open structure of the plain bearing material according to the invention qualify it for a wide range of applications. exemplary the suitability of the plain bearing material as a shoe for an iron, in particular a steam iron, should be mentioned here. This application takes advantage of the fact that the steam from the steam iron can flow through the openings of the plain bearing material without any problems. A further advantageous use of the slide bearing material consists in the use as a non-stick film for lining baking trays or baking tray molds in order to prevent the baked goods from coming into direct contact with the baking tray and to ensure good baking goods detachment after baking.

Finally, the plain bearing material according to the invention can also be used in low-maintenance and lubricated plain bearings. In the case of low-maintenance plain bearings, where “low-maintenance plain bearings” are understood to mean those with lubrication pockets and / or solid lubricant storage incorporated in the sliding layer, the plain bearing material according to the invention is particularly suitable for bearing parts with low sliding speed, in particular with oscillating or intermittent movement sequences, and / or for Bearings with a high specific load, at which no hydrodynamic lubrication is achieved and lubrication with grease and oil is not possible or is not desired. In the case of the lubricated bearings, the mesh openings serve as lubrication pockets for receiving and dispensing the lubricant.

The invention is explained in more detail below with reference to a drawing which shows exemplary embodiments. Show it: 1 a slide bearing material produced according to the invention in supervision,

2 is a sectional view according to the line II-II of FIG. 1,

3 shows a plain bearing bush formed from the plain bearing material of FIG. 1 and

4a-c the process steps for the production of a plain bearing material.

1, as in FIG.

2, a layer of a metallic carrier 3, preferably from the group bronze, steel, stainless steel, aluminum, copper, titanium or their alloys. The thickness of the metallic support is between 0.1 to

3 mm, preferably 0.2 to 2 mm. The plain bearing material further comprises a sliding layer 4 made of a sliding material. The sliding material preferably contains a plastic from the group of fluoroplastics, in particular PTFE or PTFE compound, or polyethylene, in particular ultra-high molecular weight polyethylene, perfluoroalkoxy polymers, polyimide, polyamideimide or polyether ether ketone. It can also consist of a polymer matrix. The sliding layer has a thickness of 10 μm to 3 mm, preferably 40 μm to 0.5 mm. Between the metallic carrier 3 and the sliding layer 4 there is an adhesive layer 5, which brings about a firm, resilient connection between the carrier 3 and the sliding layer 4. The adhesive slide 5 is preferably a hot melt adhesive. To improve the adhesiveness, the surface of the metallic carrier and / or the Sliding layer with usual surface treatment methods, such as. B. chromating, phosphating or sandblasting can be modified. Likewise, the use of an adhesion promoter, such as. B. an organometallic primer possible. Adhesion can also be achieved by applying a porous metal layer to the surface of the metallic carrier, in particular by sintering on bronze particles. The haf mediating metal layer can also be designed as a wire mesh, ie net or sieve. This is preferably connected to the metallic carrier in a metallic manner, for example by welding or sintering.

According to the invention, the sliding material is applied to the metallic carrier before slitting and stretching. Correspondingly, the layer composite, consisting of metallic carrier and sliding layer and possibly adhesive layer, is slit and stretched after the coating and thus obtains a mesh-like structure, the mesh openings 2 in the sliding bearing material, in contrast to methods known from the prior art for producing a sliding bearing material, not being included Sliding material are filled. The mesh openings 2 can have different geometric shapes. In the present case, a brilliant geometry has been chosen. By adapting the slitting and stretching process, mesh openings with a trapezoidal, square or round, in particular circular, shape can also be obtained.

Fig. 3 shows a plain bearing bush formed from the plain bearing material, as used, for example, in a hinge. Through the open mesh The structure of the plain bearing material can be shaped with reduced forces and therefore more gently. It proves to be an advantage that the stretched plain bearing material can also be deep-drawn. Since the bearing partner is accommodated in the cylindrical bush, the sliding layer 4 is accordingly on the inner surface of the bush. The plain bearing works completely maintenance-free and has a particularly long service life, since the abrasion particles that arise during operation of the plain bearing collect in the unclosed mesh openings and therefore cannot adversely affect the sliding behavior.

4 shows the individual process steps for the production of a plain bearing material:

4a shows the coating of a metallic carrier β by spraying its surface with the sliding material. Instead of a spray technique, the sliding material can also be applied by dipping or knife coating. Alternatively, rolling or lamination of a film is also possible

Sliding material possible.

4b shows the production of an expanded mesh 6 * from the coated metallic carrier 6. Openings are introduced into the coated carrier 6 by a cutting tool with a counter-holder 7a, 7b through offset cuts without loss of material, with simultaneous stretching deformation, as a result of which the latter is given a mesh-like structure , As can be seen in FIG. 4b, the mesh-like structure also extends into the third dimension, so that consequently the thickness of the Expanded mesh 6 * enlarged compared to that of the coated metallic carrier 6.

4c, the three-dimensional structure of the expanded metal 6 * is shown schematically in a side view. Furthermore, it is shown that the thickness of the expanded metal 6 * obtained by the combined slitting / stretching process step is reduced again by subsequent rolling or calendering. The thickness of the expanded metal 6 * is preferably rolled to a thickness of from 180 to 80% of the initial thickness of the plain bearing material 6. As shown schematically in FIG. 4c, the expanded metal 6 * is returned exactly to the initial thickness of the plain bearing material 6 before the slitting / stretching process step, whereby a two-dimensional expanded metal 6 ** is obtained.

The exemplary embodiments described above have only an explanatory function and the invention is not restricted to these exemplary embodiments. Rather, the scope of protection of the invention is defined by the following claims and their legal equivalents.

Claims

April 20, 2005 P AT E NTANS P RÜ CHE

1. A method for producing a plain bearing material (1) from a metallic carrier (3) and a sliding material (4) ^' , which comprises the following process steps: - coating the metallic carrier (3) with a sliding material (4), - slitting the layer coated in this way Carrier (3) and - stretching the carrier (3), whereby a coated expanded mesh (1) having a plurality of meshes (2) is obtained.

2. The method according to claim 1, wherein the expanded metal (1, 6 *) is rolled after stretching.

3. The method according to claim 2, wherein the expanded metal (1, 6 *) is rolled to a thickness of 180-80% of the initial thickness.

4. The method according to any one of claims 1 to 3, wherein the coating of the metallic carrier (3) is carried out by dipping, spraying or knife coating.

5. The method according to any one of claims 1 to 3, wherein the coating of the metallic carrier (3) is carried out by rolling or laminating a film.

6. The method according to any one of claims 1 to 5, wherein an adhesive layer (5) is applied to the metallic carrier (3) before coating.

7. The method according to any one of claims 1 to 6, wherein the coated expanded metal (1) is applied to a further carrier.

8. The method according to any one of claims 1 to 7, wherein the stretching of the coated metallic carrier (3) is carried out in such a way that an expanded mesh with a trapezoidal, square or round, in particular circular, shape of the mesh openings is obtained.

9. The method according to any one of claims 1 to 8, wherein the metallic carrier (3) is designed as a metal sheet consisting of a material from the group bronze, steel, stainless steel, aluminum, copper, titanium and their alloys.

10. The method according to any one of claims 1 to 9, wherein the metallic carrier (3) has a thickness of 0.1 to 3 mm, preferably 0.2 to 2 mm.

11. The method according to any one of claims 1 to 10, wherein the sliding material layer (4) applied to the metallic carrier (3) by coating has a thickness of 10 μm to 3 mm, preferably 40 μm to 0.5 mm, before the stretching process.

12. The method according to any one of claims 1 to 11, wherein the sliding material (4) contains a plastic.

13. The method according to any one of claims 1 to 12, wherein the sliding material (4) consists of a polymer compound.

14. The method according to claim 12 or 13, wherein the plastic is a high temperature plastic, preferably a group consisting of fluoroplastics, in particular PTFE and / or PTFE compound, polyethylenes, in particular ultra-high molecular weight polyethylene, perfluoroalkoxy polymers, polyimides, polyamideimides, polyether ether ketones and their combinations.

15. The method according to any one of claims 1 to 14, wherein the mesh length and the mesh width are each 0.2 to 40 mm and / or the web width and the web thickness are each 0.08 to 15 mm.

16. The method according to any one of claims 1 to 15, wherein the mesh length and the mesh width are each 1.0 to 15 mm and / or the web width and the web thickness are each 0.2 to 5 mm.

17. The method according to any one of claims 1 to 16, wherein the mesh length and the mesh width are each 1.5 to 11 mm and / or the web width and the web thickness are each 0.25 to 2.5 mm.

18. Plain bearing material produced by a method according to one of claims 1 to 17.

19. Use of a sliding material according to claim 18 as a sliding and reinforcing material in injection molded plain bearings.