PURPOSE: To maintain the accuracy of positioning a center stem highly accurately without damaging heat insulating materials in top and bottom forces by a simple means.
CONSTITUTION: A laminate 33 consisting of a plurality of rigid sheets 34 and rubber elastic sheets 35 is sealed in a metallic mold 24 consisting of top and bottom forces 21, 22 and a side mold 23. In this sealed state, a center stem 30 is inserted into through holes 27, 28, 36 located in the center of the metallic mold to position the laminate. Heaters 29 are embedded into the side mold 23, and heat insulating materials 25, 26 are disposed among the top and bottom forces 21, 22 and the laminate 33. In a structure in which the laminate 33 is integrally vulcanized under heating by the heaters 29, the heat insulating materials 25, 26 are disposed on the top and bottom forces 21, 22 at the outside places of the through holes 27, 28 into which the center stem 30 is inserted, except the places of the inner peripheral edges of the top and bottom forces where both the forces abut with the through holes. Further, gaps 37 are formed among the top and bottom forces 21, 22 and the laminate 33 at the inner peripheral edges of the forces where they abut with the through holes 27, 28. The gaps 37 constitute recessed portions 38 formed on the uppermost and lowermost rigid sheets 34, 34 of the laminate 33, or formed in the top and bottom forces 21, 22.
FUJISAWA KAZUHIRO
TAKEHARA YASUO
