Sliding layer for multilayer bearing material

Abstract

A sliding layer for a multi-layer bearing material that is free of lead. The sliding layer can include PTFE, sphalerite, and solid lubricants. The solid lubricants can include graphite and antimony oxide. In some embodiments, the sliding layer includes from 70 to 80 vol % PTFE, from 10-20 vol % sphalerite, and from 1 to 10 vol % solid lubricant (for example, graphite and antimony oxide).

We claim: 
     
         1 . A sliding layer for a multilayer bearing comprising:
 67.5 to less than 90 vol % polytetrafluoroethylene;   10 to 20 vol % primary lubricant, wherein the primary lubricant is sphalerite; and   greater than 0 to 12.5 vol % secondary lubricant;   wherein sphalerite includes zinc, iron, and sulphur.   
     
     
         2 . The sliding layer as claimed in  claim 1 , wherein the secondary lubricant is selected from the group consisting of graphite, antimony oxide, boron nitride, and combinations thereof. 
     
     
         3 . The sliding layer as claimed in  claim 1 , wherein the secondary lubricant comprises:
 0.5 to 2.5 vol % antimony oxide; and   greater than 0 to 10 vol % graphite.   
     
     
         4 . The sliding layer as claimed in  claim 3 , wherein the antimony oxide comprises nano-scale particulate having a diameter in the range of from 30 to 50 nm. 
     
     
         5 . The sliding layer as claimed in  claim 1 , wherein the sliding layer comprises:
 78.5 vol % polytetrafluoroethylene;   16 vol % sphalerite; and   5.5 vol % secondary lubricant.   
     
     
         6 . The sliding layer as claimed in  claim 5 , wherein the secondary lubricant comprises:
 4 vol % graphite; and   1.5 vol % antimony oxide.   
     
     
         7 . The sliding layer as claimed in  claim 1 , wherein the sliding layer is disposed on a bronze layer, and the bronze layer is disposed on a steel layer. 
     
     
         8 . The sliding layer as claimed in  claim 7 , wherein the sliding layer has a thickness in the range of from 1 to 125 μm. 
     
     
         9 . A sliding layer for a bearing comprising:
 70 to less than 90 vol % polytetrafluoroethylene;   10 to 20 vol % primary lubricant, wherein the primary lubricant is sphalerite; and   greater than 0 to 10 vol % secondary lubricant, wherein the secondary lubricant comprises graphite;   wherein sphalerite includes zinc, iron, and sulphur.   
     
     
         10 . The sliding layer as claimed in  claim 9 , wherein the sliding layer comprises:
 80 vol % polytetrafluoroethylene;   16 vol % sphalerite; and   4 vol % graphite.   
     
     
         11 . The sliding layer as claimed in  claim 9 , wherein the sliding layer is disposed on a bronze layer, and the bronze layer is disposed on a steel layer. 
     
     
         12 . The sliding layer as claimed in  claim 11 , wherein the sliding layer has a thickness in the range of from 1 to 125 μm. 
     
     
         13 . The sliding layer as claimed in  claim 9 , wherein the secondary lubricant consists of graphite. 
     
     
         14 . The sliding layer as claimed in  claim 1 , wherein the sliding layer is free of lead. 
     
     
         15 . The sliding layer as claimed in  claim 9 , wherein the sliding layer is free of lead. 
     
     
         16 . The sliding layer as claimed in  claim 1 , wherein the sliding layer is substantially free of lead. 
     
     
         17 . The sliding layer as claimed in  claim 9 , wherein the sliding layer is substantially free of lead.