U.S. patent application number 12/401749 was filed with the patent office on 2009-07-02 for flat gasket and method for the production thereof.
Invention is credited to Georg Egloff, Armin Gutermann, Kurt Hohe, Gunther Unseld.
Application Number | 20090166985 12/401749 |
Document ID | / |
Family ID | 26006086 |
Filed Date | 2009-07-02 |
United States Patent
Application |
20090166985 |
Kind Code |
A1 |
Hohe; Kurt ; et al. |
July 2, 2009 |
FLAT GASKET AND METHOD FOR THE PRODUCTION THEREOF
Abstract
The invention relates to a flat gasket, having at least one
metallic layer in which at least one port is formed, the metallic
layer or at least one of the metallic layers being formed at least
in regions in the form of an undulating and/or serrated profiling
around the port(s).
Inventors: |
Hohe; Kurt; (Langenau,
DE) ; Gutermann; Armin; (Leipheim, DE) ;
Unseld; Gunther; (Neenstetten, DE) ; Egloff;
Georg; (Weussenhorn, DE) |
Correspondence
Address: |
MARSHALL & MELHORN, LLC
FOUR SEAGATE, 8TH FLOOR
TOLEDO
OH
43804
US
|
Family ID: |
26006086 |
Appl. No.: |
12/401749 |
Filed: |
March 11, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11324659 |
Jan 3, 2006 |
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12401749 |
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10311553 |
May 22, 2003 |
7000924 |
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11324659 |
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Current U.S.
Class: |
277/592 |
Current CPC
Class: |
F16J 15/0818 20130101;
F16J 2015/085 20130101; F16J 2015/0837 20130101; F16J 2015/0862
20130101; F16J 15/0825 20130101; F16J 2015/0875 20130101 |
Class at
Publication: |
277/592 |
International
Class: |
F02F 11/00 20060101
F02F011/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 15, 2000 |
DE |
100 29 403.0 |
Dec 7, 2000 |
DE |
100 60 872.8 |
Jun 15, 2001 |
EP |
PCT/EP01/06807 |
Claims
1. A gasket comprising one or more metallic layers circumventing a
port, the one or more metallic layers comprising: a first portion
of one of the one or more metallic layers having a bead formed
therein, wherein said bead circumvents a port; and a second portion
of one of the one or more metallic layers defining an undulating
layer region extending around said port to form a deformation
limiter for the bead and being spaced radially from said bead, the
undulating layer region having a material thickness between two
generally opposing surfaces and defining at least one tooth, at
least one trough, and a transition region extending between said
tooth and said trough, wherein said material thickness of said
undulating layer region is generally not constant such that the
material thickness defines a taper formed within the transition
region to a material thickness that is less than the material
thickness of at least a portion of each of the tooth and the
trough, and wherein the tips of the teeth are rounded off.
2. A gasket, as in claim 1, wherein said one metallic layer is
comprised of a spring steel or a cold deformable steel that hardens
during tempering.
3. A gasket, as in claim 1, wherein the first portion and the
second portion are formed in one metallic layer.
4. A gasket, as in claim 1, wherein the first portion is formed in
a first metallic layer and the second portion is formed in a second
metallic layer.
5. A gasket, as in claim 4, wherein said second metallic layer
further comprises a bead circumventing said port.
6. A gasket, as in claim 1, wherein said material thickness is
measured generally normal to at least one of said two generally
opposing surfaces.
7. A gasket, as in claim 1, wherein in the undulating layer region,
the layer is bent in cross section.
8. A gasket, as in claim 1, wherein said teeth vary in quantity
around said port.
9. A gasket, as in claim 1, wherein the height of at least one of
said at least one tooth and said at least one trough varies around
said port.
10. A gasket, as in claim 1, wherein the undulating layer region
defines a plurality of teeth, and the spacing between said teeth
varies in different regions of the circumference around the
port.
11. A gasket comprising one or more metallic layers circumventing a
port, the one or more metallic layers comprising: a first portion
of one of the one or more metallic layers having a bead formed
therein, wherein said bead circumvents a port; and a second portion
of one of the one or more metallic layers defining an undulating
layer region extending around said port to form a deformation
limiter for the bead and being spaced radially from said bead, the
undulating layer region having a material thickness between two
generally opposing surfaces and defining a trapezoidal crest, a
trapezoidal trough, and a transition region extending between said
crest and said trough, wherein said material thickness of said
undulating layer region is generally not constant such that the
material thickness defines a taper formed within the transition
region to a material thickness that is less than the material
thickness of at least a portion of each of the crest and the
trough, and wherein the tips of the trapezoidal crests are rounded
off.
12. A gasket, as in claim 11, wherein said one metallic layer is
comprised of a spring steel or a cold deformable steel that hardens
during tempering.
13. A gasket, as in claim 11, wherein the first portion and the
second portion are formed in one metallic layer.
14. A gasket, as in claim 11, wherein the first portion is formed
in a first metallic layer and the second portion is formed in a
second metallic layer.
15. A gasket, as in claim 14, wherein said second metallic layer
further comprises a bead circumventing said port.
16. A gasket comprising a first metallic layer portion comprised of
steel and having a bead formed therein, wherein said bead
circumvents a port; and a second metallic layer portion comprised
of steel and including at least one region of undulating profiling
extending around said port to form at least a portion of a
deformation limiter for the bead, the undulating profiling and the
bead being radially spaced, wherein said undulating profiling is
defined by a material thickness between a first undulating surface
and a second, generally opposing, undulating surface, the first
undulating surface defining a tooth generally radially aligned with
a trough defined by the second undulating surface, the first
undulating surface defining a trough generally radially aligned
with a tooth defined by the second undulating surface, and the
first and second undulating surfaces defining a transition region
extending between the tooth and the trough, wherein said material
thickness of said undulating profiling is generally not constant
such that the material thickness defines a taper formed within the
transition region to a material thickness that is less than the
material thickness of the tooth and the trough, and wherein the
tips of the teeth are rounded off.
17. A gasket, as in claim 16, wherein said undulating profiling
includes a plurality of teeth having spacings therebetween and a
plurality of troughs.
18. A gasket, as in claim 17, wherein said spacings between teeth
vary around said port.
19. A gasket, as in claim 16, wherein said second metallic layer
portion further comprises a bead circumventing the port.
20. A gasket, as in claim 16, further comprising a third metallic
layer portion having a bead formed therein, wherein said bead
circumvents the port.
21. A gasket, as in claim 16, wherein said teeth vary in quantity
around said port.
22. A gasket, as in claim 16, wherein said region of undulating
profiling is plastically deformable.
Description
RELATED APPLICATIONS
[0001] This application is a continuation of the application filed
Jan. 3, 2006 and assigned Ser. No. 11/324,659, which is a
continuation of the application filed on May 22, 2003 and assigned
Ser. No. 10/311,553, now U.S. Pat. No. 7,000,924. These
applications are hereby incorporated by reference in their
entireties.
BACKGROUND OF THE INVENTION
[0002] The invention relates to a flat gasket having at least one
metallic layer in which respectively at least one port is formed
and a method for the production thereof. The single or also
multilayer flat gasket can be formed and used in particular as
cylinder head gasket but also for other faces to be sealed
together, such as the most varied flange gaskets.
[0003] In order to increase and safeguard the sealing effect of
such a metallic flat gasket over a fairly long period of time, it
is normal to form a bead, which completely encloses this port as a
rule, around the most varied ports by corresponding shaping at
least of one of the layers of such a flat gasket.
[0004] Such a bead can however only fulfill the function as long as
a certain degree of elasticity is maintained in the bead region,
which as a rule cannot be maintained without additional aids with
which a complete plastic deformation is prevented. For this purpose
normally deformation limiters are used for the beads. Such
deformation limiters are known in the most varied of embodiments
and are normally designated also as "stoppers". Thus, deformation
limiters can be obtained by bending over one of the metallic layers
or by additional elements.
[0005] In DE 298 04 534, an example of such a deformation limiter
in the form of a grooved region which is formed in a metallic layer
is described. Such a grooving is produced in the metallic layer by
cold or hot shaping. The grooving is thereby dimensioned with
respect to the thickness of the metallic layer or respectively also
taking into account specific installation conditions of such a
gasket in such a manner that the grooved region represents a
corresponding thickness increase.
[0006] However, only a limited influence can be achieved on the
desired properties with such a grooving as deformation limiter and
in particular the variation with corresponding adaptation to the
most varied of usage conditions, which can also be locally
different on a flat gasket, is only possible in a conditional
manner and in a restricted form.
SUMMARY OF THE INVENTION
[0007] In each of the suitable production methods, a change in the
metal in this region occurs, independently of whether a cold or
respectively a hot forming has been implemented which must be taken
into account for such flat gaskets at least in the choice and
shaping of the flat material.
[0008] In particular in the formation of such a grooving by
pressing into the cold metal, a corresponding wear and tear on the
pressing tool occurs so that the costly tools must be replaced at
more or less large intervals.
[0009] In addition, the grooves cannot be introduced into the
metallic layer reproducibly at any depth and at any density.
[0010] It is hence the object of the invention to make available a
flat gasket and also a method for the production thereof having at
least one metallic layer which is better adapted to the locally
occurring influences and with which such a flat gasket can be
produced economically.
[0011] Advantageous embodiments and developments of the invention
are produced with the features described herein.
[0012] In the case of the flat gasket according to the invention
which can comprise one or respectively also a plurality of metallic
layers disposed one above the other, there is inserted, in contrast
to the already mentioned, known grooving, a profiling in at least
the one metallic layer or in one of the metallic layers at least in
regions around the one or also more ports, in particular in ports
for combustion chambers in cylinder head gaskets. Such a profiling
can be formed thereby in an undulating form and/or in a serrated
form, this form being impressed into the respective metallic
layer.
[0013] The term undulating in the present invention includes also
embodiments which deviate from a sinusoidal wave. The undulation
can accordingly be flattened also into crests and troughs and have
for example straight sides. Trapezoidal embodiments also fall
within the term wave of the present invention.
[0014] The profiling is formed preferably at least in regions
around the port(s), as far as possible adapted to its external
contour. Ideally, such a profiling has three and more wave crests
or three and more teeth on each side of the gasket. In this case, a
good sealing behavior is achieved even without filling or coating
of the profiling.
[0015] If a serrated profiling is impressed, it is expedient to
correspondingly round off the tips of the individual teeth which
point alternately in the direction of both sealing faces. In the
case of a wave profile, this is of course not required. In both
cases, the respective wave crests or wave troughs can however also
be flattened out or smoothed, as a result of which a particularly
effective seating surface of the stopper on the adjacent sealing
layers is formed. Advantageously, the heights of the wave crests or
of the individual teeth, i.e. the amplitude, are not definitely
constant across the entire profiling but, in specific
circumferential regions around a port, taking into account the
respective geometric shape, can be of a different size. In the same
way, the spacings of wave crests or teeth relative to each other
can also be varied.
[0016] Different amplitudes of the teeth or wave crests and/or
different spacings between the individual teeth or wave crests and
also different radii of the waves, proceeding at an increasing
spacing from the edge of the respective port, can be set in order
to be able to locally influence in particular the elasticity and
the resilient rigidity in a targeted manner. A plastic forming of
one region of such a profiling can also be permitted thereby in a
defined manner or be undertaken already before installation of such
a flat gasket.
[0017] Furthermore the transition region between wave troughs and
wave crests or between teeth situated adjacent to each other on
oppositely situated sides can have a lower material thickness than
the wave crests/wave troughs or teeth. By suitable impressing
during production of the profiling (edge swaging) the material
thickness can also be profiled in this manner and the properties of
the profiling can be adapted to the respective specific conditions.
It is also possible to swage not the edges but rather the crests or
troughs. A so-called radius swaging then leads to a thickening of
the edges.
[0018] It can already suffice to form a profiling around the ports,
the period length of which is=1. This means that the profiling
comprises merely two wave crests or two teeth which are formed in
respectively opposed directions. Of course, a larger number of wave
crests, advantageously three or more, can however also be used.
[0019] It is particularly preferred if the profiling is used as
deformation limiter for additionally formed beads.
[0020] The possibility therefore exists with a single layer gasket
of forming a profiling according to the invention at least on one
side of one such bead, of course the possibility also being offered
of an arrangement of profiling on both sides. Preferably the
profiling is disposed on the combustion chamber side. In the case
where the profiling functions as deformation limiter and is
adjacent to a bead, the formation of the undulation, i.e. the
profile height (amplitude) and the spacing of the wave crests
(period) is coordinated to the bead. The profiling, i.e. in
particular the amplitude of the wave, must be smaller than the
extension of the bead (see for example FIGS. 4 and 6).
[0021] The profiling can however be formed even in the case of a
multi-layer seal in one layer and the bead in an adjacent
layer.
[0022] According to the invention, a flat gasket can comprise also
at least two metal layers which both have an undulating or serrated
profiling. These profilings can be placed one above the other.
Advantageously, the profilings in the two layers are designed
differently with respect to length, depth and/or radius of the
respective undulation (amplitude, profile height and radius). If
two differently designed undulating beads are compressed such in
the engine, directly in contact with each other, then the relative
movement of each of the undulating beads is dependent upon the
respective wave structure. The difference of the relative movement
of the two profilings can be used as elastic spring element for
sealing with a high tensioning force. Thus in one of the metal
sheets there is no need for the entire bead and nevertheless the
tensioning force of an entire bead can be exceeded.
[0023] Furthermore, the layer, which has the profiling, can be
reinforced in the region of the profiling by at least one further
layer, for example a ring, advantageously with the width of the
profiling. This layer or this ring can grip mound the profiled
layer also along the circumferential edge of the port at least in
regions and form there a so-called folded stopper. The reinforcing
layer or respectively the reinforcing ring can have the same
profiling and consequently both profilings can abut against each
other in a form fitting manner. Here also, the amplitude, period
and radius of the profiling of the reinforcing layer or
respectively of the reinforcing ring can however be varied along
the circumferential edge and/or perpendicularly to the
circumferential edge of the port. If the period, amplitude and
radius differ from each other on various layers of adjacently
disposed profiling, then the sealing behaviour can be specifically
influenced further in this manner.
[0024] The stopper (layer or ring) can be connected to the
modulating stopper by means of any optional welding methods. By
means of this welded-on stopper, a variable projection is achieved
which at the same time contains an elastic portion. The choice of
thickness of the additional stopper makes it possible to adapt the
gasket in the stopper region to the engine conditions. Thus, very
high and robust constructions can be achieved, for example for
diesel engines even in the sphere of lorries.
[0025] In contrast to conventional flat gaskets with deformation
limiters, bending-over or beading of layers of the flat gasket or
additional elements in order to produce deformation limiters can be
dispensed with and consequently the production costs can be
reduced.
[0026] In a preferred embodiment, an adequate and durable sealing
effect of a flat gasket according to the invention with
corresponding profiling can also be achieved if the beads
surrounding the ports have been dispensed with. In this case, the
entire function, which has been achieved previously by the bead
with deformation limiter, is achieved solely by means of the
profiling.
[0027] For this purpose, the profiling of one or more layers can be
virtually optimised by corresponding shaping and dimensioning in
that the elasticity, the resilient rigidity and also a specifically
desired degree of plastic deformation can be set in the various
regions of such a profiling. Hence, it is possible as mentioned
already initially, correspondingly to vary the spacings of the
individual wave crests or teeth from each other and/or their
heights and/or the radii of the individual waves. For example the
region of a profiling pointing in the direction of a port can also
have smaller spacings of the wave crests or teeth from each other
than the further removed regions. In the just mentioned region, the
elasticity is consequently less than in the densely packed regions
of such a profiling. The spacings and/or heights can however also
be successively enlarged, starting from the external edge of a
port. The densely packed regions of a profiling have a smaller
elasticity and, in contrast thereto, are plastically deformable in
a limited manner and this region can accordingly take over if
necessary the function of a deformation limiter.
[0028] Furthermore, a variation in the number of wave crests or
troughs or teeth, in the sheet thickness, in the heights or form,
in particular of the radii of the wave crests/wave troughs or teeth
and their spacing and the like can also be produced along the
circumference of the port, for example of a cylinder boring.
[0029] The metal layers, in which the profiling is introduced, can
also be formed differently with respect to their upper side and
underside, i.e. to both sides, which are orientated in the
installed state for example towards the cylinder head or cylinder
block, for example with respect to height and form of the wave
crests, wave troughs and the like so that the stopper can
accommodate the different properties of for example cylinder head
and cylinder block which can be manufactured from different
materials.
[0030] The layer which has the profiling can furthermore be formed
from cold deformable steel, for example a maraging steel, such as
Zapp VACL 180T which hardens by tempering for example to
300.degree. C.
[0031] The rigidity of specific regions of a profiling can also be
increased by means of webs which are disposed and formed between
the individual adjacent wave crests or teeth. Such webs can be used
in a serial or else offset arrangement. The webs can however also
be present only in one region which is disposed at a greater
spacing from the respective port.
[0032] The profiling to be inserted according to the invention can
be formed in the most varied of metallic materials, i.e. also in
various spring steel materials, an even greater elasticity and
consequently an improvement in the sealing effect being able to be
achieved with spring steel over a long period of time.
[0033] The flat gasket according to the invention can be developed
in addition in that materials known per se are applied on at least
one side of a metallic layer. Suitable materials, for example
elastomers, are mentioned for example in DE 198 29 058, DE 199 28
580 and DE 199 28 601, the disclosure content of which is referred
to in its entirety.
[0034] Such a filler is then present at least also in regions and
in parts of the profiling and the elasticity and resilient rigidity
can be influenced by means of the respective elastomer. A further
influential dimension, when using such fillers, is in addition to
their arrangement also the respective filling level in the
profiling. This means that the wave troughs of such a profiling or
the intermediate spaces between the teeth of a serrated profiling
can be filled completely but also partially so that, in addition to
the already mentioned local influence on elasticity and resilient
rigidity, the damping properties can be influenced also in various
ways.
[0035] The filling level can be changed with an increasing spacing
from the edge of the ports. It can however also be varied across
the circumference of the respective ports.
[0036] The flat gaskets according to the invention, irrespectively
of whether they are intended to be produced in a single layer or
multilayer with or without additional filler, can be produced with
few technologically, easily controllable operational steps and
consequently in a particularly economical manner.
[0037] Due to the most varied of options with respect to the
shaping and dimensioning of the profiling, properties can be set
specifically locally.
[0038] The possibility also exists of using a combination of
undulating and serrated forms within one profiling.
[0039] Attention should be drawn not least to the fact that, in the
case of a serrated profiling, the correspondingly formed layer is
bent correspondingly in cross-section and the individual teeth are
not impressed into the material, as is the case in the grooving
known in the state of the art. This applies of course analogously
to an undulating profiling also.
[0040] In the case of the flat gaskets according to the invention,
no local hardening occurs in the metal. In addition, a reduced
warping is achievable. The profilings can also be formed with hard
spring steels.
BRIEF DESCRIPTION OF THE DRAWINGS
[0041] The invention is intended to be explained in detail
subsequently with reference to embodiments which show;
[0042] FIG. 1 a sectional representation through a part of a flat
gasket according to the invention in which arm undulating profiling
forms a deformation limiter for a conventional bead;
[0043] FIG. 2 a part of a three-layer flat gasket with two
externally situated beaded layers and
[0044] FIG. 3 a part of a further example of a flat gasket
according to the invention with a variably formed profiling;
[0045] FIG. 4 a further example of a flat gasket according to the
invention;
[0046] FIG. 5 four further examples of single layer flat gaskets
according to the invention;
[0047] FIG. 6 in total eight further examples of flat gasket
according to the invention;
[0048] FIG. 7 four further examples of flat gaskets according to
the invention;
[0049] FIG. 8 an embodiment in which the profiling is formed as a
trapeze, and
[0050] FIG. 9 an embodiment in which the profiling is formed as a
radius-swaged bead.
DETAILED DESCRIPTION OF THE INVENTION
[0051] In the example of a single layer flat gasket according to
the invention, illustrated in FIG. 1, a bead 3 is formed in the
metallic layer 1 and, in the direction of a port, not shown here,
there abuts an undulating profiling 2, the wave crests and wave
troughs of which are disposed regularly and consequently the wave
crests also have a constant profile height and constant spacings
from each other. The profiling 2 fulfils in this case, in addition
to the function of a deformation limiter for the bead 3, also a
sealing function in addition due to the achievable elastic
properties.
[0052] Here as in the description of the following Figures,
corresponding reference numbers are used for corresponding
elements.
[0053] The resilient characteristics and consequently also the
elasticity can, in a non-illustrated form, be influenced by filling
the intermediate spaces between the adjacent wave crests of the
profiling 2, for example with elastomer and at different filling
levels. Of course, the intermediate spaces between the wave crests
can also be filled completely with an elastomer.
[0054] In a non-illustrated form, a corresponding profiling 2 can
be formed also on the other side of the bead 3.
[0055] A three-layer flat gasket is shown in FIG. 2. In that
example, beads 3 are again formed in the two externally situated
layers 1' of the flat gasket and a likewise undulating profiling 2
is present correspondingly in the central layer 1. Of course, the
statements with respect to options for influencing properties,
which have been made already in FIG. 1, also apply analogously to
this example.
[0056] In FIG. 3, once again a single layer metal flat gasket is
shown, the formation of an additional bead 3 having been dispensed
with in this example. The bead function in this example can also be
fulfilled by the correspondingly formed profiling 2. The spacings
and profile heights of the individual wave crests of the profiling
2, starting from the direction of the edge of a port, not shown
here, are thereby smaller than is the case in the regions of the
profiling 2 at a greater spacing from the port. The correspondingly
more closely situated regions are more rigid and can be deformed
plastically only slightly, if at all.
[0057] The region, which is further away from the port, has a
greater period length, the spacings of the wave crests from each
other are correspondingly greater, the latter also applying to the
profile height of the wave crests in this region. Consequently, a
higher elasticity and lower rigidity is present in this region of
the profiling 2. In the installed, i.e. pre-stressed state of such
a flat gasket, the region of the profiling 2 with the greater
spacing from the port can then fulfill a deformation limiter
function for the pre-positioned region of the profiling 2 due to
the mentioned properties.
[0058] The profiling can be obtained in its shape by using a
correspondingly formed and dimensioned impressing tool already
during forming. However the possibility exists of producing such a
shaping of this region in a second technological operational step
by corresponding swaging and pressing.
[0059] It is advantageous if the firstly obtained profiling 2 is
planished subsequently completely or in regions so that in the
planished region the profile height is reduced again. For this
purpose, one or two stamps with flat pressing faces orientated
parallel or diagonally at an angle towards the surface of the metal
layer 1 can be pressed onto the region to be planished. During
planishing, the metallic layer 1, in particular at the edges of the
profiling 2 should be braced. Due to the subsequently implemented
planishing, the rigidity and the hardness of the profiling 2 can be
increased and consequently also the rigidity of a flat gasket
according to the invention.
[0060] Since in the examples of flat gaskets according to the
invention, illustrated in the FIGS. 1 to 3, representative limits
are set by the choice of sectional representations, it should be
indicated that the profiling, as seen across the circumference,
i.e. in various radial axes, can be shaped and dimensioned
differently. Thus the possibility exists of varying the number of
successively disposed wave crests or teeth across the circumference
and/or of undertaking a corresponding change in the spacings and
profile heights of the profiling.
[0061] FIG. 4 shows a further example of a single layer flat
gasket, having a single metal layer 1 in which a bead is impressed.
An undulating stopper region 2 is disposed between the bead 3 and
the port situated on the right. Said stopper region has in total
three wave crests and three wave troughs. Underneath this stopper
region, a ring 8 is welded-on along the circumferential edge of the
port, said ring having the same profiling as the metal layer 1 and
abutting against the latter in a form fit. In the ring 8, a
profiling 2' with three wave crests and three wave troughs is
formed likewise as a result. With an additional stopper ring 8 of
this type, the flat gasket according to the invention can be
adapted to variable engine geometries or engine conditions in which
both the width and the material thickness of the metal ring 8 are
chosen correspondingly.
[0062] FIG. 5 shows details of four further flat gaskets comprising
respectively one single layer. This individual layer can equally be
a component of a multi-layer gasket. The illustrated flat gaskets
in FIGS. 5A and 5C have the same material thickness, whilst the
flat gaskets shown in FIGS. 5B and 5D have a greater layer
thickness. In contrast, the undulations in the stopper region 2 in
FIGS. 5A and 5B have a smaller radius of curvature than in the flat
gaskets in FIGS. 5C and 5D. It is shown here consequently that, by
means of a different material thickness of the layer and also by
means of different forming of the profiled regions 2 of the layer
1, greater clearance for adaptation possibilities of this stopper 2
to various engine characteristics are offered.
[0063] Furthermore, in all the profiled regions 2 illustrated in
FIG. 5, respectively the material thickness in an intermediate
region 6 between a wave crest 7 and an adjacent wave trough 7 is
smaller than in the region of the wave troughs or wave crests 7. As
a result, the elastic behaviour of the stopper regions 2 can also
be varied.
[0064] FIG. 6 shows in total eight different variants of flat
gaskets according to the invention. FIG. 6A shows an in total
six-layer flat gasket comprising six metal layers 1a to 1f. In the
layer 1b and in the layer 1e, two profiled stopper regions 2b or 2e
are formed respectively as deformation limiters for the beads 3a,
3c, 3d or 3f formed in the layers 1a, 1c, 1d and 1f.
[0065] A corresponding five-layer gasket is illustrated in FIG. 6B
in which once again two layers are provided with profiled stopper
regions. In this case, an intermediate layer 1c is interposed
between the two upper layers 1a and 1b and the two lower layers 1d
and 1e, said intermediate layer having neither a bead nor being
profiled.
[0066] Three-layer flat gaskets are illustrated in FIGS. 6C to 6E,
the intermediate layer 1b having a step 4 in FIG. 6D. A profiled
stopper region 2c, which functions as stopper for the bead 3c, is
adjacent to the step 4 on one side. As a result of the fact that an
offside is provided in the layer 1b which offset is orientated away
from the stopper region 2c, the elastic stopper function of the
profiled region 2c across the layer 1b which is offset in the
profiled region of the layer 1c is used also for the bead 3a in the
layer 1a. FIGS. 6F and 6G show two-layer flat gaskets in which a
profiled region 2b is formed in respectively one of the gasket
layers. Said region serves as stopper (deformation limiter) for the
beads 3b in FIG. 6F or the beads 3a and 3b in FIG. 6G.
[0067] FIG. 6H shows in turn a four-layer flat gasket, respectively
one bead 3a and 3d facing towards each other being formed in both
external layers 1a and 1d. These two external layers 1a and 1d
enclose two further layers 1b and 1c which have no bead. They have
however regions 2b and 2c which are chosen laterally adjacent to
the beads 3a and 3d, said regions having the same profiling and
abutting against each other in a form fit. These two layers 1b and
1c form a stopper (deformation limiter) in the profiled region for
the beads 3a and 3d by means of the parallel extending profiled
regions 2b and 2c. Due to this arrangement of two parallel profiled
regions, the sealing effect and the deformation limiting can be
adapted to the respective conditions of the engine to be
sealed.
[0068] If alternatively, in the gasket according to FIG. 6H for the
two layers 1b and 1c in the region of the undulating profiling 2b
and 2c, different lengths, depths and/or a different radius of the
undulations is used in the two profilings, then the extended length
of the two profilings is different when compressed in the engine
for the two layers 1b and 1c. This difference of the relative
movement leads to narrow annular contacts between these two
profilings 2b and 2c. Such an arrangement can be used for sealing
as an elastic spring element with a high tensioning force which can
exceed the tensioning force of one complete bead. In this case, a
purely two-layer gasket can also be used, only the two gasket
layers 1b and 1c of the four gasket layers in FIG. 6H forming the
gasket together.
[0069] FIG. 7 shows here further examples of flat gasket according
to the invention. FIG. 7A thereby shows a flat gasket which has two
metallic layers 1a, 1b. The layer 1b is provided with a bead 3
against which a profiled region 2 abuts directly adjacent to the
port. The layer 1a adjacent to the layer 1b is not profiled, but
grips around the layer 1b along the circumferential edge of the
port and thus forms a stopper ring 9 on the opposite layer 1b.
Hence the deformation limiting stopper effect is produced from the
cooperation of the profiling 2 with the stopper 9.
[0070] In FIG. 7B, a corresponding two-layer flat gasket is
illustrated as in FIG. 7A. The regions of the layer 1A directly
adjacent to the profiled region, designated here with 2B, of the
layer 1b, are provided in the same way with a profiling 2a or 2c so
that the layer 1a abuts in a form fit against the profiled region
2B of the layer 1b on both sides.
[0071] FIG. 7C shows an arrangement as in FIG. 7A, however the
layer 1a being provided not as a whole-surface metallic layer, but
only as stopper ring 8 in the region of the profiling 2 of the
metallic layer 1. Once again the stopper 8 grips around the layer 1
along the circumferential edge of the port and forms a second
stopper 9. This concerns consequently a folded stopper.
[0072] A folded, stopper ring 8, 9 is illustrated in FIG. 7D in a
corresponding manner to FIG. 7C, however the regions 2A or 2C of
the stopper 8, 9 directly adjacent to the profiling, designated
here with 2B, of the layer 1 being profiled likewise in a similar
manner to the layer 1 in the profiling region 2b and thus abutting
on both sides against the profiling 2b in a form fit. This
consequently concerns here also a profiled folded stopper.
[0073] In further examples, both the amplitude and the spacing of
the individual wave crests can be varied not only within the
profiling 2b, either along the circumferential edge of the port or
also in a perpendicular direction to the circumferential edge of
the port, but also the profiled regions 2A and 2C can in a similar
manner have a profiling with different amplitudes and wave spacings
in particular wave crests between the individual layers at adjacent
places can deviate from each other. Thus the profiling 2a and 2c in
FIGS. 7B and 7D can have wave crest heights or wave crest spacings
at points adjacent respectively to the profiling 2b which are
different from the latter. By corresponding choice of amplitudes
and periods of the profiling in the individual layers and stopper
rings, a specific influencing of the deformation limitation and of
the elastic properties of the flat gasket directly adjacent to the
port is possible.
[0074] In FIG. 8, an embodiment is now shown in which the profiling
2 is formed in the shape of a trapeze. The trapeze comprises
accordingly uniform trapezes which are disposed in a row. In the
embodiment of FIG. 8a, an edge angle is provided which can be
between 0 and 30 degrees. FIG. 8b shows a further embodiment in
which the trapezoidal profiling 2 is adjacent to a bead 3. It is
essential in the embodiments according to FIGS. 8b and 8c and 8d
that the profiling 2 in its amplitude, i.e. in the profile height,
and the spacing of the wave crests from each other (periods) differ
clearly from the profiling of the bead 3. The profile height of the
profiling is accordingly half or less than that of the bead 3.
[0075] The embodiment of FIGS. 8b and 8d are formed comparably with
respect to the profiling 2 and the bead 3. The FIG. 8c shows a
two-layer variant, each of the two layers having an identical
profiling. In contrast, an embodiment is also possible in which
only one of the two active layers--as here in 8d the lower
layer--shows the profiling according to the invention.
[0076] Whichever of the corresponding embodiments are chosen
depends upon the respective purpose of use, i.e. upon the
conditions for which the gasket is provided.
[0077] A particular advantage of the embodiments according to the
invention according to FIG. 8 can be seen in the fact that, by
flattening the wave crests and wave troughs, i.e. by forming a
trapeze for the profiling, better sealing conditions are achieved,
which obviously can be attributed to the fact that this embodiment
leads to significantly reduced recesses on the top and/or block
side.
[0078] FIG. 9 shows a further embodiment of the profiling 2. Only
the profiling is shown in the embodiment according to FIG. 9. This
profiling 2 can be disposed once again, as also shown in FIGS. 8a
to 8d, adjacent for example to a bead and be disposed in one, two
or three layer concepts.
[0079] The advantage of the embodiment according to FIG. 9 can be
seen in the fact that here a radius-swaged undulating bead is used,
i.e. a profiling, in which the undulation has been swaged in the
crests and troughs so that the result is material strengthening at
the edges. This embodiment is distinguished by a particularly good
behavior with respect to recessing on the cylinder in a block
and/or top side. The advantage of this variant can also be seen in
the fact that the elastic behaviour can once again be set
specifically by the degree of swaging. According to whether the
material thickening in the edges is more or less reinforced with
respect to the embodiment according to FIG. 8, this leads to a
change in the elastic behavior. In FIG. 9 a corresponding
dimensioning is indicated in order to clarify the plastic
deformation.
[0080] The embodiment according to FIG. 9 has proved to be
particularly preferred.
* * * * *