US Patent 7425295 Production method of tone wheel

A Production method of tone wheel made of elastic material to be fixed to a rotating member in which a magnetic encoder is assembled in combination of the tone wheel and a magnetic sensor provided at a fixed member. The tone wheel is produced by using newly designed an assembled molding die which comprises one die blocks and the other die blocks which are detachably engaged each other, and which has a flash groove at matching surface where the distal of the one die blocks and that of the other die blocks are matched. The one die blocks have an annular molding surface formed on the magnetic die member side of the assembled die, and the other die blocks have an annular molding receiving surface part which is formed with an annular molding surface.