Seal for a joint or juncture – Seal between fixed parts or static contact against... – Contact seal between parts of internal combustion engine
Patent
1998-03-24
2000-12-26
Knight, Anthony
Seal for a joint or juncture
Seal between fixed parts or static contact against...
Contact seal between parts of internal combustion engine
277298, 277593, 277591, 2191171, 219 87, F16J 1508
Patent
active
06164661&
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The invention relates to an improvement of a cylinder head gasket of an engine.
BACKGROUND OF THE INVENTION
A cylinder head gasket is known in the art comprising a gasket body having a combustion chamber opening formed in alignment with a cylinder bore, and a shim ring surrounding the combustion chamber opening, the shim ring being spot welded along a circumferentially extending weld line to the gasket body (Japanese Laid-Open Patent Application No. 293,700/1995).
The spacing of the spot weldings is chosen so as to enable the shim ring to be firmly welded to the gasket body. With a recent trend toward achieving a higher output from the engine, the spacing of the spot weldings need be reduced. However, this causes a distortion to be produced in the shim ring under the influence of heat generated during the welding operation. Thus there has been a definite limit on the spacing of spot weldings which can be reduced.
DISCLOSURE OF THE INVENTION
In view of the foregoing, the invention provides a cylinder head gasket which allows a higher welding strength to be achieved, even with spot welding, than in the prior art without accompanying a distortion in a shim ring.
Thus, the invention relates to a cylinder head gasket comprising a gasket body having a combustion chamber opening formed in alignment with a cylinder bore, and a shim ring surrounding the combustion chamber opening, the shim ring being spot welded along a circumferentially extending weld line to the gasket body. In accordance with the invention, the pitch of spot welding or the weld spacing is varied to define a zone of a high welding density and a zone of a low welding density in the circumferential direction of the shim ring.
With the arrangement of the invention, the weld spacing in the zone of a low welding density can be set to a high value below which a distortion would occur in the shim ring when spot weldings are effected at such value of weld spacing around the entire circumference of the shim ring. On the other hand, the weld spacing in the zone of a high welding density can be set to a low value which would cause a distortion to occur in the shim ring when spot weldings are effected at this low value of the weld spacing around the entire circumference of the shim ring.
Thus the occurrence of a distortion in the shim ring under the influence of heat can be prevented if the weld spacing in the zone of a high welding density is chosen to be a low value which would cause a distortion to occur in the shim ring under the influence of heat and if the weld spacing in the zone of a low welding density is chosen to be a high value below which a distortion would occur in the shim ring under the influence of heat. It will be evident that a shim ring for which welding took place with these weld spacings provides a higher welding strength than when spot weldings took place with a high value of weld spacing around the entire circumference.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a plan view of a cylinder head according to one embodiment of the invention;
FIG. 2 is an enlarged view of the left end shown in FIG. 1; and
FIG. 3 is an enlarged view of spot weldings which take place in a zone of a high welding density.
BEST MODE OF CARRYING OUT THE INVENTION
The invention will be described below with reference to an embodiment which is applied to the cylinder head gasket of a tandem six cylinder engine.
Referring to FIG. 1, a cylinder head gasket 1 includes a gasket body 2 formed of a relatively thick metal member. The gasket body 2 is formed with six combustion chamber openings 2A to 2F, located on a line and at an equal interval, in alignment with cylinder bores in the cylinder head, not shown.
Bolt holes 3 are formed in the gasket body 2 at a plurality of locations around the combustion chamber openings 2A to 2F for passing clamping bolts therethrough which connect between the cylinder head, not shown, and the cylinder block.
The gasket body 2 need not be constructed with a single plate, but may comprise a plurality o
Kakuta Hirotaka
Nakata Kazuya
Sato Akio
Uchida Kenji
Knight Anthony
Peavey Enoch
Taiho Kogyo Co. Ltd.
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