The invention concerns reinforcing rings comprising a bearing ring (3) that is made of an insulating material which is compression proof even at high working temperatures and a metal clamping ring (4) into which the bearing ring is fitted to form a double body; said reinforcing rings are used in electric motor collectors with lamellar inner webs (6) that are used for bracing the individual lamellae, that project inward running at least predominantly parallel to the collector axis (2) and that have undercut surfaces (8, 7) for rear engagement by the reinforcing rings. In this way reinforcing rings can be made from two subrings that are simple to manufacture and simple to press together, or by using an injection process to insert the bearing ring in the clamping ring, thus forming a unit of extremely high thermal and mechanical load-bearing capacity and giving the collector a very high stability and fatigue strength.