Synchronizer ring

The present invention relates to a synchronizer ring having an annular body which has a sliding region, the sliding region being provided with a wear-resistant tribological coating. According to the invention, it is provided for the tribological coating to be a thermally sprayed coating which contains a maximum of approximately 40% by weight of solid lubricant.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiment of a synchronizer ring 1 according to the invention which is diagrammatically depicted in FIG. 1 has an internal sliding face. The synchronizer ring therefore slides on a transmission cone along its inner circumference. The synchronizer ring 1 has a ring body 2 and a wear-resistant tribological layer 4 on the surface of the inner circumference 3 of the ring body 2 . The ring body 2 is made from metal or metal alloy, for example iron, copper or aluminium or their alloys. According to the invention, the wear-resistant tribological layer 4 contains less than 40% by weight titanium dioxide. The particle size of the TiO 2 is at most approximately 180 &mgr;m. The layer 4 also contains tin, zinc, silicon, manganese, nickel, copper and/or aluminium in variable proportions. As well as being in elemental form, these materials may also be present in the form of carbides and/or in the form of oxides and/or in the form of nitrides. In addition, the layer 4 may also contain carbon. The coating has a porosity of up to approximately 30%, preferably approximately 20%. To produce the layer 4 , the surface of the inner circumference 3 of the ring body 2 was initially roughened, for example sand-blasted and degreased. Then, the layer 4 was applied by the wire arc spraying process, which is known per se, using one or two filled wires. If only one filled wire is used, the second wire consisted of CuAl8. After it had been applied, the layer 4 was stamped with the aid of a ram (not shown). A filled wire 10 is diagrammatically depicted in FIG. 3 . It has a covering 11 of aluminium or CuAl8 and a filling 12 which contains less than 40% by weight titanium dioxide with a particle size of up to approximately 200 &mgr;m, preferably up to 180 &mgr;m and particularly preferably up to approximately 150 &mgr;m. The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof.