Plain bearing composite material

Abstract

The invention relates to a plain bearing composite material, comprising a supporting layer (12) made of steel, a bearing metal layer (14) made of copper or a copper alloy, which is applied to the supporting layer (12), and a functional layer (16) made of aluminum or an aluminum alloy, which is applied to the bearing metal layer (14).

Claims

1. A plain bearing composite material, comprising a supporting layer (12) made of steel, a bearing metal layer (14) made of copper or a copper alloy that is applied to the supporting layer (12), and a roll bonded functional layer (16) made of an aluminum alloy that is applied to the bearing metal layer (14), and wherein the aluminum alloy of the functional layer contains tin and except for unavoidable impurities is lead-free and in that the bearing metal layer (14) has a layer thickness (h2) of 50 to 595 m, wherein the aluminum alloy of the roll bonded functional layer consists of, except for impurities, 5-25 wt. % tin, 1.5-3.0 wt. % silicon, 0.2-2.0 wt. % copper, 0.2-1.5 wt. % manganese, a total of a maximum of 0.4 wt. % and individually a maximum of 0.2 wt. % of at least one element from the group vanadium, chromium, zirconium, and titanium, and the rest aluminum.

2. The plain composite material in accordance with claim 1 wherein the bearing metal layer (14) comprises a lead-free bronze or brass layer.

3. The plain bearing composite material in accordance with claim 1 wherein the supporting layer (12) and the bearing metal layer (14) form a two-component composite (18), wherein the bearing metal layer (14) is cast, sintered, or plated onto the supporting layer (12).

4. The plain bearing composite material in accordance with claim 1 wherein a coating (20) is applied to the functional layer (16).

5. The plain bearing composite material in accordance with claim 4, wherein the coating (20) is a polymer lubricant lacquer (22).

6. The plain bearing composite material in accordance with claim 4 wherein the coating (20) is applied to the functional layer (16) chemically, by means of spray lacquering, or electrochemically.

7. The plain bearing composite in accordance with claim 4 wherein the functional layer (16) is roughened.

8. A bearing shell made of a plain bearing composite material in accordance with claim 1.

9. The bearing shell in accordance with claim 8 wherein the functional layer (16) has a layer thickness (h3) of 5 m to 500 m.

10. The bearing shell in accordance with claim 8 wherein the bearing metal layer (14) and the functional layer (16) have a total thickness of 200 to 600 m.

11. The plain bearing composite material in accordance with claim 1, wherein the aluminum alloy of the roll bonded functional layer includes 10-20 wt. % tin.

12. A plain bearing having a first bearing shell and a second bearing shell, the first bearing shell and the second bearing shell being made of a plain bearing composite material comprising a supporting layer (12) made of steel, a bearing metal layer (14) made of copper or a copper alloy that is applied to the supporting layer (12), and a roll bonded functional layer (16) made of aluminum alloy that is applied to the bearing metal layer (14), the aluminum alloy of the functional layer (16) contains tin and except for unavoidable impurities is lead-free, wherein the first bearing shell and the second bearing shell are combined to create a journal bearing, wherein the bearing metal layer (14) of the first bearing shell has a layer thickness (h21) of 150 m to 595 m and the functional layer (16) of the first bearing shell has a layer thickness (h31) of 5 m to 50 m; wherein the bearing metal layer (14) of the second bearing shell has a layer thickness (h22) of 50 m to 550 m and the functional layer (16) of the second bearing shell has a layer thickness (h32) of 50 m to 500 m, and wherein the total thickness of the bearing metal layer and the functional layer of the first bearing metal layer and the total thickness of the bearing metal layer and the functional layer of the second bearing shell are essentially equal, wherein the aluminum alloy of the roll bonded functional layer consists of, except for impurities, 5-25 wt. % tin, 1.5-3.0 wt. % silicon, 0.2-2.0 wt. % copper, 0.2-1.5 wt. % manganese, a total of a maximum of 0.4 wt. % and individually a maximum of 0.2 wt. % of at least one element from the group vanadium, chromium, zirconium, and titanium, and the rest aluminum.

Description

THE DRAWINGS

(1) The invention shall be described in detail using preferred embodiments and referencing the attached drawings.

(2) FIG. 1 depicts a first embodiment of an inventive plain bearing composite material;

(3) FIG. 2 depicts a second embodiments of the inventive plain bearing composite material; and,

(4) FIG. 3 depicts an embodiment of an inventive plain bearing.

DETAILED DESCRIPTION

(5) The first embodiment of an inventive plain bearing composite material 10.sub.1 depicted in FIG. 1 includes a supporting layer 12, a bearing metal layer 14 with a copper basis that is applied thereto, and a functional layer 16 with an aluminum basis that is applied to the bearing metal layer 14. A plain bearing shell (not shown) is produced from the plain bearing composite material 10.sub.1 as part of a plain bearing. The supporting layer 12 and the bearing metal layer 14 form a two-component composite 18 that is produced for example by casting, sintering, or plating the bearing metal layer. The two-component composite 18 is then supplied for instance to a plating station for joining the functional layer. There the functional layer 16 is applied to the bearing metal layer 14, preferably using roll bonding.

(6) The free surface of the functional layer 16 forms a slide surface 19 of a bearing element produced from the inventive plain bearing composite material 10. For instance a journal bearing (bush or bearing shell) may be produced from this composite material by shaping (bending or rolling) or a thrust washer may be produced from this composite material by punching. The supporting layer 12 is produced for instance from a tempering steel C22, the bearing metal layer 14 from a copper alloy of the CuNi2Si type, and the functional layer 16 from an aluminum alloy of the AlSn20 type.

(7) The supporting layer 12 has a layer thickness h.sub.1, the bearing metal layer 14 has a layer thickness h.sub.2, and the functional layer 16 has a layer thickness h.sub.3. Regardless of the rest of the layer structure, a steel band is used for the supporting layer 12, the layer thickness h.sub.1 of which is between 900 and 1300 m in the finished composite material. The layer thicknesses h.sub.2 of the bearing metal layer 14 and h.sub.3 of the functional layer 16 depend on the amount of stress on the bearing shell. Information on the preferred ranges may be found at the end of the description of the figures. In the example depicted in FIG. 1, the layer structure is designed in particular for improved conformability and embeddability of the finished bearing element.

(8) FIG. 2 depicts a second embodiment of the inventive plain bearing composite material 20. The sequence of the supporting layer 22, bearing metal layer 24 with copper basis, and the functional layer 26 with aluminum basis is the same as that of the first exemplary embodiment. The thicknesses are different, however. While the supporting layer is produced from the same steel band and therefore has the same thickness, the bearing metal layer 24 has a significantly thicker layer thickness h.sub.2 and the functional layer 26 has a significantly thinner layer thickness h.sub.3 than in the first exemplary embodiment. This layer structure is designed especially for improved bearing strength and fatigue strength of the finished bearing element.

(9) In addition, a coating or entry layer 28, in the example depicted a polymer lubricant lacquer that forms the slide surface 30 of a bearing element produced from the inventive plain bearing composite material 20, is applied to the functional layer 26. For improved adhesion of the polymer lubricant lacquer to the functional layer 26, the latter is roughened prior to the lubricant lacquer being applied. The polymer lubricant lacquer preferably has PAI (polyamide-imide) and includes fillers (not shown). The polymer lubricant lacquer has a layer thickness h.sub.4 that is preferably between 5 and 20 m.

(10) FIG. 3 illustrates an inventive plain journal bearing 100 that is made in a known manner from a first semicircular plain bearing shell 110 and a second semicircular plain bearing shell 120. So-called split lines 102 may be seen between the plain bearing shells 110 and 120. The first plain bearing shell 110 for instance forms the lower bearing shell of a connecting rod bearing and the second plain bearing shell 120 forms the upper bearing shell of the connecting rod bearing.

(11) The first plain bearing shell 110 has, in approximately the layer structure of the plain bearing composite material 10 in accordance with the first exemplary embodiment, a supporting layer 112 made of steel, a somewhat thinner bearing metal layer 114 with a copper basis and a thickness h.sub.21, and a somewhat thicker functional layer 116 with an aluminum basis and a thickness h.sub.31. Therefore the first or lower plain bearing shell is in fact designed for lighter loads but improved embedding behavior.

(12) The second plain bearing shell 120 has, in approximately the layer structure of the plain bearing composite material 20 in accordance with the second exemplary embodiment, a supporting layer 122 made of steel, a thicker bearing metal layer 124 with a copper basis and a thickness h.sub.22, and a thinner functional layer 126 with an aluminum basis and a thickness h.sub.32, to which an entry layer 130 has been applied. Therefore the second or upper plain bearing shell is designed for heavier loads, which is even further favored by the application of an entry layer.

(13) Overall the thicknesses of the layers in the bearing shells for such a journal bearing preferably remain within the following ranges (at varying wall thicknesses, due to profiling, all figures in m relate to the main load area, which is typically in the area of the apex of the bearing shell): a) Bearing Shell with Higher Loads 900h.sub.111300; preferably 1000h.sub.111200 200h.sub.21+h.sub.31600; preferably 300h.sub.21+h.sub.31500 5h.sub.3150; 150h.sub.21595; preferably 250h.sub.21495 optionally 5h.sub.4120
where h.sub.11=layer thickness of the supporting layer, h.sub.21=layer thickness of the bearing metal layer, h.sub.31 =layer thickness of the functional layer, and h.sub.41=layer thickness of the optional entry layer b) Bearing Shell with Lighter Loads 900h.sub.121300; preferably 1000h.sub.121200 200h.sub.22+h.sub.32600; preferably 300h.sub.22+h.sub.32500 50h.sub.32500; preferably 150h.sub.32350 50h.sub.22550; preferably 100h.sub.22350
where h.sub.12=layer thickness of the supporting layer, h.sub.22=layer thickness of the bearing metal layer, and h.sub.32=layer thickness of the functional layer.

(14) One embodiment of the inventive plain journal bearing has the following layer thicknesses and tolerances (again in m): a) Bearing Shell with Higher Loads h.sub.11=110050 h.sub.21+h.sub.31=40050 5h.sub.3150 b) Bearing Shell with Lighter Loads h.sub.12=110050 h.sub.22+h.sub.32=40050 150h.sub.32300

(15) The ranges of values for h.sub.21 and h.sub.22 may be computed if 400 m is assumed for the totals of the bearing metal layer thickness and functional layer thickness (h.sub.2n+h.sub.3n).

(16) It may be seen from FIG. 3 and from the information provided above that the thickness of the supporting layers and the total bearing metal thickness of the functional layer and of the bearing metal layer for the upper and lower plain bearing shells are preferably selected to be equal. There are clear advantages for production. For one thing, the bands may be produced with the same thickness as intermediate products for both bearing shells, taking into account any excess. The shaping machines for shaping plates produced from the bands do not have to be changed over, because the thicknesses are the same. Finally, it is not necessary to change over the machine that is used to profile and machine the bearing shell to its final size. This is because both the intermediate product (re-shaped bearing shell) and the final product (profiled bearing shell) have the same overall thickness. Thus the plain bearing shells may be individually and optimally adapted to the various requirements depending on the installation position in the engine and combined to make a pair without significantly increasing the complexity of the machining.