A plain bearing is described having a bearing metal layer, supported by a support shell, made of an aluminum or copper alloy and having a lead-free running layer, possibly applied to the bearing metal layer over an intermediate layer, made of a zinc matrix having at least one further alloy element. To achieve good tribological properties, it is suggested that the zinc matrix of the running layer contains 1 to 49 wt.-% bismuth as an additional alloy element.
1. A plain bearing having a bearing metal layer made of an aluminum or copper alloy supported by a support shell and having a lead-free running layer made of a zinc matrix comprising 31 to 99 wt.-% zinc and having at least one further alloy element, wherein the zinc matrix of the running layer contains 1 to 49 wt.-% bismuth as the additional alloy element.
2. The plain bearing according to claim 1 , wherein the zinc matrix of the running layer contains 4 to 40 wt.-% bismuth.
3. The plain bearing according to claim 1 , wherein the zinc matrix contains, in addition to bismuth, at least one further alloy element from a group of alloy elements comprising iron, cobalt, manganese, copper, nickel, silver, tin, antimony, titanium, chromium, molybdenum, and tungsten, the individual proportion of these alloy elements making up 0.01 to 15 wt.-%, but the total proportion being at most 20 wt.-%.
4. The plain bearing according to claim 3 , wherein the individual proportion of the alloy elements from the group of alloy elements comprising iron, cobalt, manganese, copper, nickel, silver, tin, antimony, titanium, chromium, molybdenum, and tungsten is between 0.1 and 10 wt.-%.
5. The plain bearing according to claim 3 , wherein the at least one alloy element from the subgroup of alloy elements is at least one of iron, cobalt, and copper and the proportion of the subgroup is at least 0.2 wt.-%, but at most 3 wt. %, the individual proportion of each alloy element in the subgroup being between 0.02 and 3 wt-%.
6. The plain bearing according to claim 3 , wherein the individual proportion of the alloy elements from the group of alloy elements comprising iron, cobalt, manganese, copper, nickel, silver, tin, antimony, titanium, chromium, molybdenum, and tungsten is between 0.3 and 5 wt.-%.
7. The plain bearing according to claim 1 , wherein the running layer is covered by a running-in layer made of bismuth.
8. The plain bearing according to claim 1 , further comprising an intermediate layer between the bearing metal layer and the lead-free running layer.
9. The plain bearing according to claim 1 , wherein the zinc matrix of the running layer contains 10 to 30 wt.-% bismuth.