-2-
FIELD OF INVENTION
The present invention relates to an improved gasket. The present
invention in particular relates to elastomeric oil sump gasket
having varying thickness of elastomeric profile on the crankshaft
bearing cap/hump.
BACKGROUND/PRIOR ART
A gasket is a mechanical seal which fills the space between atleast
two mating surfaces, generally to prevent leakage from or into the
joined objects while under compression.
In modern automobile industry, gasket seal carries lot of
importance as seepage causes failure of seal leading to run, drip,
leak which seriously affects the performance of the part. In sealing
around a hole/port/opening where moderate temperature and
pressure are applied, a gasket member may be formed of an elastic
member, or the gasket member may be provided on a base plate
with a soft sealing material around a hole to be sealed. However,
when the gasket is tightened between engine parts by bolts,
portions of the gasket in proximity to the bolt holes are especially
strongly compressed, so that the portions near the bolt holes lose
compressibility or resiliency in a long usage thereby causing
leakage threat.
A limited number of joining requirements are adequately met by
means of a gasket with a molded upstanding bead or beads on one
or both sides of the gasket so as to create a more conformable seal
by virtue of the higher unit loading than could be created with the
same material unbeaded; these gasket types are customarily made
from solid elastomeric materials.
-3-
Beads are and have been employed with considerable success in
the manufacture of exhaust manifold and head gaskets on cars
and trucks. These bead types are created by embossing gaskets,
which are customarily varnish-like coated steel, steel which has
been perforated or tanged and lined on one or both sides with
materials such as non-asbestos paper, non - asbestos millboard
(treated or untreated), or non - asbestos elastomeric sheet
packings.
Now, reference may be made to the following Patents:-
US Patent No. 4,535,996 provides improved oil pan gaskets for
automotive use, comprising a pair of side sections, each having a
rigid core member, as of metal, defining a plurality of core holes,
the metal core members extending along side portions of
the gasket assembly. Elastomeric envelopes substantially surround
each of the core members and have side sections of a first
thickness. The stop members are of a second thickness less than
the first thickness. As such, when the gasket assembly is
compressed between elements to be sealed, the stop members limit
compression and limit displacement of the elastomeric envelopes to
prevent splitting of them.
US Patent No. 4997193 describes improved gasket, such as one
which may be used in an oil pan sealing environment, is of a
generally rectangular configuration, and has a pair of sides and a
pair of ends each defining elongated and expansive surfaces in
plan view, the sides being of a first thickness and the ends being of
second and third thicknesses which may be different from each
other and which are greater than the first thickness. Each of the
sides and ends has a central rigid core, such as a metallic core,
having upper and lower surfaces and facing layers adhesively
secured to and covering the upper and lower surfaces of the core.
-4-
The gasket is flat, but the ends are bendable to assume and
maintain arched configurations in use.
Publication No. EP0485815 discloses an improved molded gasket
assembly especially adapted for use as an oil pan gasket or the like
is provided. The gasket assembly includes an integrally formed pair
of elastomeric side sections and pair
of elastomeric end sections and a rail in and associated with each
of the side sections. Each rail comprises an elongated rigid plastic
member having a generally flat main body of a first thickness and
a plurality of integrally formed, longitudinally spaced stops, each of
which stops defines a fastener opening through which a fastener is
adapted to pass. The stops are of a height substantially greater
than the first thickness, but less than the thickness of the
associated side section. A plurality of apertures is formed in each
rail through which elastomer projects to integrate the rail and the
elastomer of the associated side section.
Publication No. JPH0464776 provides a metal gasket having a
resilient metal plate, that is a substrate of stainless steel, for
example, a combustion chamber hole, etc., are bored in this
substrate, and a bead and inclined parts are formed in it. A
circular metal plate, or a spacer of stainless steel, or a so-called
shim ring, for example, is fixed to the bead on the side of a
protruding part.
US Patent No. 5,492,343 provides a molded
elastomeric gasket that includes a formed metal wire element
serving as an internal stiffener member. The wire element is bent
to a desired configuration and the ends of the wire element may be
welded together to form a continuous, closed form element.
-5-
US Patent No. 3,837,657 discloses a gasket structure with an
upstanding bead on one or both sides, the density of which is
always less than that of the unbeaded portion to provide maximum
compressibility with maximum sealing conformability. The beads
created depend on the spring-like effect developed by the
embossing of the varnish-like coated steel and/or the steel insert
in the gaskets that are lined with the materials mentioned.
US Patent No. 6,702,296 describes gaskets with seal enhancement
zones positioned at selected locations within a web or webs of the
gasket. The gasket includes a base sheet, which, in the illustrated
embodiment, is made of a porous
gasket material, but may be made from other types of gasket
materials such as, for example, laminated, rubberized, or metal
core gasket materials.
US Patent No. 5,975,540 discloses sealing member which is formed
of a foamed rubber having small holes therein. The sealing section
has closed small holes therein to provide the compressibility and
form the surface pressure thereon, and the pressure affecting
portion has crushed small holes therein by crushing the small
holes of the foamed rubber in advance. Thus, the pressure
affecting portion has substantially no compressibility or elasticity.
US Patent No. 6,354,599 relates to a gasket with a compressible
sealing member and a hard support layer for sealing around a
hole. The compressible sealing member is disposed on at least one
side of the gasket member to surround the first
hole adjacent thereto without surrounding the second holes. The
hard coating is disposed on the same side as that of the
compressible sealing member to surround the second holes. The
hard coating is formed independently from the compressible
sealing member, and does not substantially have compressibility.
-6-
US Patent No. 8,496,253 discloses a metallic flat gasket comprising
a gasket layer having at least one combustion chamber throughopening
which is surrounded by an elastically deformable sealing
element which is configured in the form of an undulatory profiling
in the gasket layer in such a way that on each of the surfaces of
the gasket layer at least two wave crests and two wave troughs are
present. The invention combines in the specifically configured
sealing element the functions of an elastic element (for example a
bead) and a (rigid) stopper of a conventional gasket in a single
element. The undulatory profiling can in this case have an
exclusively linear form or curve, for example, at the corners of the
gasket.
Publication No. DE3831414 is directed to a molded rubber seal,
especially for use in internal combustion engines, with a metal
insert that is surrounded by a rubber elastic material and holes for
passage of screws, which serve to connect the molded rubber seal
enclosing components. Such molded rubber seals, for example,
and an oil pan gasket between the engine block sump or as a
cylinder head cover gasket between the cylinder head and cylinder
head cover of an internal combustion engine. Thus the rubberelastic
material upon tightening the seal in the joint between the
components to be connected is not pressed inadmissible. The
molded rubber gasket having holes in the sheet metal material
worked out by cold forming bush-shaped compression limiter.
Publication No. CN201326435 discloses oil pan gasket, with a ring
in front of the dragon, including a set of bolt mounting holes along
the spacer ring settings, characterized by: mounting holes provided
in the rigid liner, the liner is less than the height of the spacer
thickness. Said liner is a metal material.
-7-
Another prior art provides an oil pan gasket which utilizes the onepiece
molded rubber technology and includes compression limiters
to prevent over tightening. They have either a solid steel core or a
rigid carrier design, and in some cases the side rails are trimmed
for stroker engines.
Though prior art attempts to provide an enhanced seal within
selected regions or zones of a gasket web by simply applying a
bead of a rubber or polymer based sealant to the surface of the
gasket web. While such solutions can be somewhat successful,
they nevertheless have certain inherent problems and
shortcomings. For instance, beads of sealant applied to a gasket's
surface increases the effective thickness of the gasket in the region
of the bead. This can result in less than optimal distribution of
clamping forces when the gasket is clamped between a pair of
flanges, which can degrade rather than enhance the resulting seal.
Further, surface applied with sealant beads generally have not
been proven to provide a completely satisfactory barrier against
interfacial migration of fluid across the web faces of the gasket.
Thus, there exists a need for a gasket that provides an enhanced
seal in selected regions or zones where additional sealing is
required without the shortcomings inherent in surface sealant
beads and in other conventional methods to provide such
selectively positioned seal enhancement zones.
Therefore, the present invention provides an improved elastomeric
oil sump gasket in which elastomeric profile on the crankshaft
bearing cap has varying thickness to ensure proper load
distribution for effective sealing and desired compression of
elastomer.
-8-
OBJECTS OF THE INVENTION
The principal object of the present invention is to provide a
singular elastomeric oil sump gasket having varying thickness of
elastomeric profile on the crankshaft bearing cap/hump for
enhanced sealing on bearing cap/hump and at corners/junctions.
Another object of the present invention is to provide an elastomeric
oil sump gasket in which the hump area is provided with variable
rubber beading to accommodate the variable sealing gap profile.
Yet another object of the present invention is to provide an
elastomeric oil sump gasket which ensures proper load
distribution for effective sealing, desired compression of elastomer
and ease of assembly which in turn results in optimal stress on
sump body.
Still another object of the present invention is to provide an
elastomeric oil sump gasket which helps to enhance the sealing
loads at the junction by means of elastomeric reinforcement at the
junction of flat part of gasket and crankshaft bearing cap/hump.
SUMMARY OF THE INVENTION
According to this invention, it provides an improved gasket
comprises atleast two longitudinal members connected by means
of an arched member at both ends having varying thickness and
made of a central core of a material embedded in another material.
The present invention provides an improved elastomeric oil sump
gasket with metal inserts and compression limiters in which
elastomeric profile on the crankshaft bearing cap has varying
thickness which ensures proper load distribution for effective
-9-
sealing and desired compression of elastomer. The elastomeric
reinforcement at the junction of flat part of gasket and crankshaft
bearing cap/hump helps to enhance the sealing loads at the
junction.
In a preferred embodiment of the present invention, the gasket
assembly comprises a central rigid but flexible metallic core having
upper and lower surfaces and facings a suitable rubber
composition secured to the upper and lower surfaces of the core
and a metal spacer preferably of steel. The gasket also includes
plurality of. holes situated on the longitudinal member for receiving
bolts therein to tighten the sump onto the engine block with
gasket.
In still another embodiment of the present invention, the
elastomeric profile on the crankshaft bearing cap/hump has
varying thickness seal to ensure proper load
distribution for effective sealing and to ensure desired
compression of elastomer. Desired compression of elastomer in
turn results in optimal stress on sump body.
In another embodiment of the present invention, the electrometric
reinforcement provided at the junction of flat part of gasket and
crankshaft bearing cap/hump enhances sealing loads at the
junction.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Further objects and advantages of this invention will be more
apparent from the ensuing description when read in conjunction
with the accompanying drawings of preferred embodiments and
wherein:
-10-
Fig. 1 illustrates an embodiment of elastomeric oil sump gasket in
accordance with the present invention.
Fig. 2 illustrates locations provided with additional rubber
thickness / gasket thickness with elastomer reinforcement.
Fig. 3 illustrates the hump area provided with variable rubber
beading according to present invention.
Fig. 4 illustrates the structure of oil sump of present invention.
DETAIL DESCRIPTION OF THE INVENTION WITH REFERENCE
TO THE ACCOMPANYING DRAWINGS:
The invention is directed to improved gasket. Reference may be
made to figure 1, 2 and 4 indicating an improved elastomeric oil
sump gasket having varying thickness of elastomeric profile on the
crankshaft bearing cap to ensure proper load distribution for
effective sealing and desired compression of elastomer. The gasket
assembly of invention comprises two longitudinal members (1, 2)
which are connected by means of an arched member (3) at both
ends. The arched member (3) constituting hump having variable
rubber beading as shown in fig. 3. The gasket assembly is made of
a central rigid but flexible metallic core (M) with upper and lower
surfaces and facings made of a suitable elastic member (R) secured
to the upper and lower surfaces of the core and a metal spacer (S)
preferably of steel. The longitudinal member (2) of the gasket also
includes plurality of holes (H) for receiving bolts therein to tighten
the gasket.
The elastic sealing member may be soft rubber or foamed rubber
having good heat and wear resistances as well as compressibility.
-11-
The elastic sealing member may be silicone rubber, nitrile rubber,
polyacrylic rubber, polyurethane rubber or fluorine rubber. Other
foamed or soft materials or synthetic resins suitable for sealing
may be used.
A plurality of bolt holes are provided in each of the longitudinal
members (1, 2) of the gasket to accommodate bolts that clamp the
gasket between a pair of mating surfaces such as flanges to create
a seal.
According to a preferred embodiment of the present invention, the
gasket comprises a number of seal enhancement zones which are
strategically located in selected regions of the gasket webs. These
seal enhancement zones are located in the regions of the gasket
webs intermediate the bolt holes. Such a positioning may be
selected where, for example, it is determined that a good seal is
provided by the gasket in the vicinity of the bolt holes as a result of
the substantially higher clamping pressures applied by the bolts in
these regions. In another embodiment, the gasket of the present
invention is provided with additional rubber thickness / gasket
thickness at different locations preferably at corners for added
sealing advantage at corners.
Also, the hump area at the end of the gasket longitudinal members
is provided with variable rubber beading to accommodate the
variable sealing gap profile. Thus, the elastomeric profile on the
crankshaft bearing cap has varying thickness. It seals engine oil at
engine block and sump flange. This varying thickness seal not only
ensures proper load distribution for effective sealing but also
ensures desired compression of elastomer. Desired compression of
elastomer in turn results in optimal stress on sump body. In
conjunction with the above, there is provision of elastomeric
-12-
reinforcement at the junction of flat part of gasket and crankshaft
bearing cap seal which helps to enhance the sealing loads at the
junction.
It is to be noted that the present invention is susceptible to
modifications, adaptations and changes by those skilled in the art.
Such variant embodiments employing the concepts and features of
this invention are intended to be within the scope of the present
invention, which is further set forth under the following claims:-

•13
WE CLAIM;
1. An improved gasket comprises atleast two longitudinal
members connected by means of an arched member at both
ends having varying thickness and made of a central core of
a material embedded in another material.
2. An improved gasket as claimed in claim 1, wherein the
longitudinal members, is provided with plurality of holes for
receiving bolts therein to tighten the gasket.
3. An improved gasket as claimed in claim 1 or 2, wherein
another longitudinal member is having a number of bolt
holes.
4. An improved gasket as claimed in any of the preceding
claims, wherein the arched member constituting a hump
having variable rubber beading to accommodate the variable
sealing gap profile.
5. An improved gasket as claimed in any of the preceding
claims, wherein the central core is made of a rigid but
flexible metallic core with upper and lower surfaces and
facings made of a suitable elastic member secured to the
upper and lower surfaces of the core and a metal spacer
preferably of steel.
6. An improved gasket as claimed in claim 5, wherein a spacer
is located adjacent to the holes.
7. An improved gasket as claimed in any of the preceding
claims, wherein the elastic member may be made of foamed
or soft materials or sjmthetic resin suitable for sealing such
as soft rubber or foamed rubber having good heat and wear
resistance as well as compressibility, silicone rubber, nitrile
rubber, polyacrylic rubber, polyurethane rubber, fluorine
rubber.
•14-
8. An improved gasket as claimed in any of the preceding
claims, wherein a number of seal enhancement zones are
located in the regions of the gasket webs intermediate the
bolt holes.
9. An improved gasket as claimed in any of the preceding
claims, wherein additional rubber thickness/gasket
thickness is provided at different locations preferably at
corners for additional sealing advantage.
10. An improved gasket as claimed in any of the preceding
claims, comprising elastomeric reinforcement at the junction
of flat part of gasket and crankshaft bearing cap seal, which
helps to enhance the sealing loads at the junction.