Title:
VALVE SEAT AND MANUFACTURE THEREOF
Document Type and Number:
Japanese Patent JPS56106015
Kind Code:
A
Abstract:
PURPOSE:To increase wear resistance of a valve seat and to facilitate attaching of the valve seat to the cylinder head, by manufacturing the valve seat by coupling a superficial layer portion including the contact surface and a base layer portion having a different composition of constituent materials from that of the superficial layer portion by way of sintering, so that these two layer portions of the valve seat have respectively a required void ratio. CONSTITUTION:A valve seat of this invention is obtained by coupling, by way of sintering, a superficial layer portion including a contact surface to be brought into repeated contact with the valve face and a base layer portion having a different composition of constituent materials from that of the superficial layer which is to be press fitted into a hole formed in the bottom surface of the cylinder head. Here, the void content of the superficial layer portion is selected to be 5-20% and that of the base layer portion is selected to be lower than 5%. In manufacturing the valve seat, an annular sintered element R having a superficial layer portion and a base layer portion is at first fabricated and it is inserted into an annular groove 6 formed by a lower punch 4 with its base layer portion being located above. Then, the element R is forged by rolling an upper punch 7 while urging the element R upward by the lower punch 4 and forcing the conical forging surface of the upper punch 7 onto the element R.
Inventors:
KIYOTA FUMIO
TAKEMURA KAZUTOSHI
FUJITA TATSUO
TAKEMURA KAZUTOSHI
FUJITA TATSUO
Application Number:
JP778880A
Publication Date:
August 24, 1981
Filing Date:
January 28, 1980
Export Citation:
Assignee:
RIKEN KK
International Classes:
F01L3/02; B22F7/02; B22F7/06; F01L3/22; F01L3/24; (IPC1-7): F01L3/02; F01L3/22