U.S. patent application number 15/606177 was filed with the patent office on 2017-09-14 for sealing element and method for producing a sealing element.
The applicant listed for this patent is ElringKlinger AG, ElringKlinger Kunststofftechnik GmbH. Invention is credited to Klaus Hocker, Patrick Klein, Fabian Kopp, Walter Schuhmacher, Claudia Stern.
Application Number | 20170261106 15/606177 |
Document ID | / |
Family ID | 54707782 |
Filed Date | 2017-09-14 |
United States Patent
Application |
20170261106 |
Kind Code |
A1 |
Hocker; Klaus ; et
al. |
September 14, 2017 |
SEALING ELEMENT AND METHOD FOR PRODUCING A SEALING ELEMENT
Abstract
In order to provide a sealing element which ensures a reliable
seal and which can be produced easily and economically, it is
proposed that a main body of the sealing element is formed from a
partially fluorinated or fully fluorinated thermoplastic material
which is injection-moldable.
Inventors: |
Hocker; Klaus; (Ingersheim,
DE) ; Schuhmacher; Walter; (Bietigheim-Bissingen,
DE) ; Klein; Patrick; (Leinfelden-Echterdingen,
DE) ; Kopp; Fabian; (Tamm, DE) ; Stern;
Claudia; (Tannhausen, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ElringKlinger AG
ElringKlinger Kunststofftechnik GmbH |
Dettingen
Bietigheim-Bissingen |
|
DE
DE |
|
|
Family ID: |
54707782 |
Appl. No.: |
15/606177 |
Filed: |
May 26, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/EP2015/077950 |
Nov 27, 2015 |
|
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15606177 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F16J 15/32 20130101;
F16J 15/3208 20130101; F16J 15/56 20130101; F16J 15/3284 20130101;
B29C 45/0055 20130101; B29C 45/0001 20130101; F16L 33/30 20130101;
F16J 15/3212 20130101; F16J 15/328 20130101; B29C 45/37 20130101;
F16J 15/3236 20130101; F16L 11/121 20130101 |
International
Class: |
F16J 15/3284 20060101
F16J015/3284; F16J 15/3236 20060101 F16J015/3236; B29C 45/00
20060101 B29C045/00; F16J 15/3208 20060101 F16J015/3208 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 28, 2014 |
DE |
10 2014 224 378.5 |
Claims
1. A sealing element for providing a seal between a first media
space filled with a first medium and a second media space filled
with a second medium in the region of a movable component, which is
guided or is guidable through the sealing element displaceably
along a longitudinal axis of the movable component and/or rotatably
along the longitudinal axis, wherein the sealing element comprises
a main body, which has two dynamic sealing portions which abut or
are abuttable against the movable component, wherein each dynamic
sealing portion has a sealing lip, wherein each sealing lip
comprises one, two or more sealing edges, wherein the main body is
formed from a partially fluorinated or fully fluorinated
thermoplastic material which is injection moldable.
2. The sealing element according to claim 1, wherein the main body
of the sealing element has obtained at least part of its final
outer shape or only part of its final outer shape or its entire
final outer shape by means of turning and/or machining.
3. The sealing element according to claim 1, wherein an inner side
or underside of the main body facing towards the movable component
in the mounted state of the sealing element is subjected to a
finishing operation after a shaping step.
4. The sealing element according to claim 1, wherein a
fluoropolymer content of the thermoplastic material, in respect of
its mass and/or its volume, is at least approximately 85%,
preferably at least approximately 90%, for example approximately
94%.
5. The sealing element according to claim 1, wherein a
fluoropolymer content of the thermoplastic material, in respect of
its mass and/or its volume, is at most approximately 99%,
preferably at most approximately 96%, for example approximately
94%.
6. The sealing element according to claim 1, wherein a carbon fiber
content of the thermoplastic material, in respect of its mass
and/or its volume, is at least approximately 0.5%, preferably at
least approximately 2%, for example approximately 4%.
7. The sealing element according to claim 1, wherein a carbon fiber
content of the thermoplastic material, in respect of its mass
and/or its volume, is at most approximately 10%, preferably at most
approximately 6%, for example approximately 4%.
8. The sealing element according to claim 1, wherein a graphite
content of the thermoplastic material, in respect of its mass
and/or its volume, is at least approximately 0.5%, preferably at
least approximately 1.5%, for example approximately 2%.
9. The sealing element according to claim 1, wherein a graphite
content of the thermoplastic material, in respect of its mass
and/or its volume, is at most approximately 6%, preferably at most
approximately 4%, for example approximately 2%.
10. A use of a partially fluorinated or fully fluorinated plastics
material, which is injection-moldable, for producing a sealing
element, in particular a sealing element according to claim 1.
11. A method for producing a sealing element, in particular a
sealing element according to claim 1, comprising: producing a main
body of the sealing element from a partially fluorinated or fully
fluorinated thermoplastic material which is injection-moldable.
12. The method according to claim 11, wherein the main body of the
sealing element obtains at least part of its final outer shape or
only part of its final outer shape or its entire final outer shape
by means of turning and/or machining.
13. The method according to claim 11, wherein an inner side or
underside of the main body facing towards the movable component in
the mounted state of the sealing element is subjected to a
finishing operation after a shaping step.
14. The method according to claim 11, wherein one or more sealing
edges and/or indentations and/or recesses are formed and/or
subjected to a finishing operation by means of turning and/or
machining.
15. The method according to claim 14, wherein the turning and/or
machining is performed with use of an axially and radially movable
tool, which is guided axially and radially along the main body in
accordance with an inner contour of said main body to be
produced.
16. The method according to claim 14, wherein the turning and/or
machining is performed with use of a tool which comprises a
processing edge, in particular a processing blade, complementary to
the inner contour of the main body to be produced.
17. The method according to claim 16, wherein the tool is guided
against the main body from the inside out in a radial direction, in
particular in such a way that the desired inner contour of the main
body is completed in a processing step without axial movement.
18. The method according to claim 11, wherein the thermoplastic
material is produced as a compound material from (according to
weight and/or volume) approximately 94% fluoropolymer,
approximately 4% carbon fiber, and approximately 2% graphite.
19. The method according to claim 11, wherein the thermoplastic
material is brought in succession, in successive zones of a
plasticizing unit of a compounding facility, to the following
temperatures: 80.+-.20.degree. C., 340.+-.20.degree. C.,
360.+-.20.degree. C., 365.+-.20.degree. C., 350.+-.20.degree. C.,
340.+-.20.degree. C.
20. The method according to claim 11, wherein the thermoplastic
material is brought in succession, in successive zones of a
plasticizing unit of an injection molding facility for producing
sealing elements, to the following temperatures: 350.+-.20.degree.
C., 365.+-.20.degree. C., 370.+-.20.degree. C., 375.+-.20.degree.
C., 380.+-.20.degree. C.
Description
RELATED APPLICATION
[0001] This application is a continuation of international
application No. PCT/EP2015/077950 filed on Nov. 27, 2015, and
claims the benefit of German application No. 10 2014 224 378.5
filed on Nov. 28, 2014 which are incorporated herein by reference
in their entirety and for all purposes.
FIELD OF DISCLOSURE
[0002] The present invention relates to a sealing element, in
particular for use as a rod seal, piston seal and/or shaft
seal.
[0003] Such a sealing element is known by way of example from DE 10
2012 112 594 A1.
SUMMARY OF THE INVENTION
[0004] The object of the present invention is to provide a sealing
element which ensures a reliable seal and which can be produced
easily and economically.
[0005] This object is achieved by way of example by a sealing
element according to claim 1.
[0006] It can be favorable if the sealing element comprises a main
body made of a thermoplastic material, wherein the main body has
obtained at least part of its final outer shape in a high-pressure
process and/or in a high-temperature process.
[0007] Alternatively, it can be provided that the sealing element
comprises a main body made of a thermoplastic material, wherein the
main body has obtained only part of its final outer shape in a
high-pressure process and/or in a high-temperature process.
[0008] The sealing element, in particular the main body of the
sealing element, is preferably produced with near net shape.
[0009] A final outer shape is in particular the shape that the main
body has in the state of use of the sealing element or in the state
ready for use.
[0010] A final outer shape is also in particular a shape in which
there is no further processing, for example no re-shaping of the
surface, before the main body is used as intended as part of the
sealing element.
[0011] It can be advantageous if the main body, at least in part or
only in part, has a surface finish which comprises a body shaped
and/or completed in a high-pressure process and/or in a
high-temperature process.
[0012] It can be advantageous if the main body, at least in part or
only in part, has a surface finish which comprises a body shaped
and/or completed in an injection molding process.
[0013] In one embodiment of the invention it can be provided that
the main body is substantially annular.
[0014] The main body preferably comprises one or more radially
inner sealing portions and also one or more radially outer sealing
portions with respect to the annular shape.
[0015] For simplification, the sealing portions will be discussed
hereinafter in the singular. However, a plurality of sealing
portions having one or more of the mentioned features can of course
also be provided at all times.
[0016] The main body can be of circular annular shape by way of
example.
[0017] A radially inner sealing portion serves preferably to
provide a dynamic seal on a movable element, in particular a
piston, a rod, or a shaft.
[0018] A radially outer sealing portion serves preferably to
provide a static seal on a housing of a sealing device.
[0019] It can be favorable if the radially inner sealing portion
and/or the radially outer sealing portion has obtained its final
outer shape in the high-pressure process and/or in the
high-temperature process.
[0020] It can be provided here that only the radially inner sealing
portion or only the radially outer sealing portion or both the
radially inner sealing portion and the radially outer sealing
portion have obtained the final outer shape in the high-pressure
process and/or in the high-temperature process.
[0021] Alternatively or additionally, it can be provided that a
radially inner sealing portion and/or a radially outer sealing
portion have obtained the respective final outer shape by means of
a finishing operation, for example a machining operation.
[0022] In a further development of the invention it can be provided
that the main body comprises two ends which are opposite one
another with respect to an axial direction and which in particular
in the state of use of the sealing element come into contact with
fluids to be separated from one another.
[0023] Only one of the ends or both ends have obtained the final
outer shape preferably in the high-pressure process and/or in the
high-temperature process.
[0024] Alternatively or additionally, it can be provided that only
one of the ends or both ends have obtained the final outer shape by
means of a finishing operation, for example a machining
operation.
[0025] One end or both ends are preferably provided with one or
more spring element receptacles for receiving one or more spring
elements.
[0026] It can be favorable if the main body comprises a
thermoplastic material which in particular can be injection molded,
or is formed from a thermoplastic material which in particular can
be injection molded.
[0027] The thermoplastic material can be in particular a
fluoro-thermoplastic material, for example a fully fluorinated
thermoplastic material.
[0028] The main body is preferably an injection-molded component,
in particular a plastics injection-molded component.
[0029] The sealing element can be a spring-loaded groove ring, for
example.
[0030] The sealing element then preferably comprises one or more
spring elements, which for example are formed from a spring steel
and have an annular shape at least roughly.
[0031] Here, one or more spring elements by way of example can have
a U-shaped, V-shaped or L-shaped cross-section as considered at
right angles to a circumferential direction.
[0032] One or more spring elements are preferably self-gripping, in
particular in such a way that the one spring element or the
plurality of spring elements are fixable without undercut in the
spring element receptacle of the sealing element.
[0033] The present invention also relates to the use of a sealing
element, in particular a sealing element according to the
invention, as a rod seal, piston seal and/or shaft seal.
[0034] Here, the sealing element is preferably used in a fuel pump
and/or a piston pump for sealing two media spaces.
[0035] The use according to the invention preferably has one or
more of the features and/or advantages described in conjunction
with the sealing element according to the invention.
[0036] The present invention also relates to a method for producing
a sealing element.
[0037] In this regard, the object of the invention is to provide a
method by means of which a sealing element that provides a reliable
seal can be produced easily and economically.
[0038] This object is achieved in accordance with the invention by
a method according to the independent method claim.
[0039] The method preferably comprises the following:
[0040] producing a main body of the sealing element from a
thermoplastic material, wherein the main body obtains at least part
of its final outer shape or only part of its final outer shape in a
high-pressure process and/or in a high-temperature process.
[0041] The method according to the invention preferably has one or
more of the features and/or advantages described in conjunction
with the sealing element according to the invention and/or the use
according to the invention.
[0042] It can be favorable if the high-pressure process comprises
an embossing process, a press molding process, an injection molding
process and/or a diecasting process.
[0043] The main body thus obtains at least part of its final outer
shape or only part of its final outer shape preferably in an
embossing process, a press molding process, an injection molding
process and/or a pressure diecasting process.
[0044] Alternatively or additionally, it can be provided that the
high-temperature process comprises a hot embossing process, a hot
press molding process, an injection molding process, a casting
process, a sintering process and/or a thermoforming process.
[0045] The main body thus obtains at least part of its final outer
shape or only part of its final outer shape preferably in a hot
embossing process, a hot press molding process, an injection
molding process, a casting process, a sintering process and/or a
thermoforming process.
[0046] It can be favorable if the main body of the sealing element
is subjected to a finishing operation only in part after the
high-pressure process and/or the high-temperature process have/has
been performed.
[0047] By way of example, a partial finishing only on one side can
be provided, in particular a one-sided finishing axially and/or
radially.
[0048] However, it can also be provided that the main body is
subjected to a finishing operation on both sides in the axial
direction and/or on both sides in the radial direction.
[0049] The main body is preferably machined.
[0050] Alternatively or additionally, it can be provided that the
main body is coated for the finishing or as the finishing.
[0051] One or more sealing portions of the sealing element are
preferably produced by a processing of the main body.
[0052] By way of example, it can be provided that one or more
dynamic sealing portions of the sealing element and/or one or more
static sealing portions of the sealing element are produced by a
processing, in particular a machining, of the main body.
[0053] One or more spring element receptacles for receiving one or
more spring elements are preferably not subjected to a finishing
operation, but instead obtain their final outer shape preferably in
the high-pressure process and/or in the high-temperature
process.
[0054] It can be particularly advantageous if the main body is
produced from partially fluorinated or fully fluorinated
thermoplastic material which preferably is injection-moldable.
[0055] It can be provided that the main body is formed from pure
PTFE material.
[0056] The thermoplastic material (plastics material) is preferably
melt-processable.
[0057] The plastics material used is preferably a TFE copolymer
with a comonomer content of more than 0.5 wt %. By means of a
comonomer content of this order, the molecular weight of the
polymer chains can be reduced without detriment to the mechanical
strength of the material, and therefore the melt viscosity is
reduced and processing by means of injection molding is made
possible.
[0058] The comonomer is preferably selected from a perfluoroalkyl
vinyl ether, in particular perfluoromethyl vinyl ether,
hexafluoropropylene and perfluoro-(2,2-dimethyl-1,3-dioxole).
Depending on the comonomer content, the fully fluorinated
thermoplastic is then what is known as a melt-processable PTFE
(comonomer content up to approximately 3 wt. %), a PFA (more than
approximately 3 wt. % perfluoroalkyl vinyl ether as comonomer), an
MFA (more than approximately 3 wt. % perfluoromethyl vinyl ether as
comonomer), or an FEP (more than approximately 3 wt. %
hexafluoropropylene as comonomer).
[0059] The TFE copolymer can also comprise different comonomers. It
is also possible that the fully fluorinated thermoplastic comprises
a mixture of different TFE copolymers.
[0060] The material of the main body can be formed in part or
substantially completely from the fully fluorinated thermoplastic.
Alternatively or additionally, the material can comprise one or
more fillers, in particular pigments, friction-reducing additives
and/or additives increasing the thermal resistance, in order to
further optimize the properties of the sealing element and to adapt
these to the relevant requirements.
[0061] The sealing element is suitable in particular for sealing
pistons in high-pressure fuel pumps or piston pumps for brake
systems (ABS, ESP, etc.).
[0062] In particular, a thermoplastic material that is resistant to
high-temperature and/or chemicals, in particular PEEK, PEAK, PEI,
etc., and/or a compound material comprising one or more of the
above-mentioned materials can also be used as thermoplastic
material.
[0063] A high dimensional stability of the thermoplastic material
can be attained in particular by production of the main body of the
sealing element in an injection molding process so as to ultimately
seal off higher pressures in particular.
[0064] The high-pressure process is in particular a high-pressure
forming process.
[0065] The high-temperature process is preferably a
high-temperature forming process and/or a high-temperature
conversion process.
[0066] It can be provided that the high-pressure process and/or the
high temperature process are the only process steps or step for
producing the main body.
[0067] Alternatively, further process steps can be carried out in
order to produce the main body.
[0068] By way of example, in order to produce a main body of a
sealing element, it can be provided that the thermoplastic material
is pre-fabricated in an extrusion process, in particular a ram
extrusion process, and is then brought into the final outer shape
by grinding and milling, turning, or other machining operation.
[0069] It can also be provided that a main body of a sealing
element is produced by carrying out the following method steps:
extruding the thermoplastic material, in particular melt-extruding
the thermoplastic material; grinding; machining in a turning
machine; hot embossing; CNC finishing, in particular in order to
produce an inner contour, for example one or more radially inner
sealing portions.
[0070] It can be provided that a main body of the sealing element
obtains at least part of its final outer shape or only part of its
final outer shape or its entire final outer shape by means of
turning and/or machining.
[0071] By way of example, it can be provided that an inner side or
underside of the main body facing towards the movable component in
the mounted state of the sealing element is subjected to a
finishing operation after a shaping step.
[0072] In particular, one or more sealing edges and/or indentations
can be formed and/or subjected to a finishing operation by turning
and/or machining.
[0073] The turning and/or machining can be performed by way of
example with use of an axially and radially movable tool, which is
guided axially and radially along the main body in accordance with
the inner contour of the main body to be produced.
[0074] It can also be provided that the turning and/or machining is
performed by way of example with use of a tool which comprises a
processing edge, in particular a processing blade, complementary to
the inner contour of the main body to be produced. The tool
preferably can be guided on the main body from the inside out in a
radial direction, in particular in such a way that the desired
inner contour is completed in a processing step without axial
movement.
[0075] In a further embodiment it can be provided that a main body
of the sealing element is produced by carrying out the following
method steps: pressing a blank; carrying out a sintering process;
hot embossing; CNC processing, in particular in order to produce an
inner contour, for example one or more radially inner sealing
portions.
[0076] A main body of a sealing element can also be produced for
example by carrying out the following method steps: pressing a
blank; carrying out a sintering process; CNC processing of the main
body, in particular in order to produce an outer contour and/or an
inner contour, for example in order to produce one or more radially
inner sealing portions and/or one or more radially outer sealing
portions.
[0077] A main body of a sealing element can also be produced by
carrying out the following method steps: granulating a starting
material; using this starting material in an injection molding
process in order to produce the main body; subjecting the main body
to a finishing operation as appropriate, in particular CNC
processing in order to produce an inner contour, for example one or
more radially inner sealing portions.
[0078] A completed main body can be connected as appropriate to
further components of the sealing element, or can be assembled
thereon, and finally packaged.
[0079] The geometry of the sealing lips has a decisive influence on
the tightness and the longevity of the sealing element.
Consequently, the selection of the optimal geometry is one of the
key challenges in the production of a sealing element.
[0080] By way of example, the lip geometry with a preferred lip
thickness and a preferred lip contact angle together with a spring
force and an overlap of the seal profile relative to a diameter of
the movable component (in particular piston rod diameter) result in
the radial force, which is very important for the dynamic
tightness. The sealing edges of the dynamic sealing lips load the
movable component with this radial force.
[0081] This radial force is decisive for the setting of the surface
pressure distribution in the sealing regions and also has a
decisive influence on the service life of such a sealing element.
Excessively high radial forces lead to increased wear of the
sealing element and accordingly to early failure thereof. By
contrast, insufficient radial forces lead to an inadequate
tightness of the sealing element.
[0082] An optimal setting of the radial force results in a surface
pressure distribution in the region of the sealing edges which
allows the best-possible recovery of the removed lubricating film.
This surface pressure distribution is dependent on the geometry of
the sealing lip as a whole, on the geometry of the sealing edges,
on the geometry and the spring properties of the spring element,
and on the changes over time to the geometries and the spring
properties, caused by wear and deformation of the sealing
element.
[0083] A further challenge is the demolding of a double-acting seal
in the injection molding process, if this shaping process is
selected for production of at least a portion of the sealing
element. Optimally formed sealing lips and sealing edge geometries
would be heavily deformed during the demolding of the inner core at
the temperature prevailing in the mold. For this reason, the inner
geometry of the sealing lip/sealing edges must be changed so that
the demolding can be performed without excessively damaging the
sealing edges. A number of measures have proven to be advantageous
for this purpose. In particular, a finite element simulation of the
demolding process on earlier geometries has led to astonishing
results.
[0084] It has surprisingly been found that the distribution of the
radial forces over the sealing edges during the demolding is
important.
[0085] In order to provide a simpler description of the geometry of
the sealing element, all details in this description are oriented
preferably towards a cross-section of the sealing element in a
plane running through the axis of symmetry. Any one-dimensional
and/or point-related details consequently result in lines or
curves, in particular annular curves, with interpolation to the
entire sealing element. Any two-dimensional and/or line-related or
curve-related details consequently result in surfaces, in
particular annular surfaces, with interpolation to the entire
sealing element. Any two-dimensional and/or surface-related details
consequently result in spaces, in particular annular spaces, with
interpolation to the entire sealing element.
[0086] By way of example, it is advantageous if a spacing between a
sealing edge and a recess, which adjoins said sealing edge in a
manner directed inwardly in the axial direction, is at least
roughly of equal size for each sealing edge.
[0087] A spacing in this description and the accompanying claims is
in particular:
[0088] (i) a spacing along a direction running parallel to an upper
side or surface of the sealing lip facing away from the at least
one sealing edge, or
[0089] (ii) a spacing along a direction running at right angles to
an upper side or surface of the sealing lip facing away from the at
least one sealing edge, or
[0090] (iii) a spacing along a direction running parallel to the
axis of symmetry of the sealing element, i.e. a spacing in the
axial direction, or
[0091] (iv) a spacing along a direction running at right angles to
the axis of symmetry of the sealing element, i.e. a spacing in the
radial direction.
[0092] A recess in this description and the accompanying claims is
in particular:
[0093] (i) a point of an indentation in the sealing lip which
locally has a maximum spacing from the axis of symmetry in relation
to the radial direction, or
[0094] (ii) a point of an indentation in the sealing lip which
locally has a minimum spacing from an upper side or surface of the
sealing lip, in particular in relation to a direction of thickness
of the sealing lip, or
[0095] (iii) the indentation as a whole.
[0096] By way of example, a spacing between a sealing edge which is
an outer sealing edge in the axial direction and a recess adjoining
this sealing edge in a manner directed inwardly in the axial
direction can be at least approximately 0.5 mm, preferably at least
approximately 0.6 mm.
[0097] Furthermore, a spacing between a sealing edge which is an
outer sealing edge in the axial direction and a recess adjoining
this sealing edge in a manner directed inwardly in the axial
direction can be at most approximately 1.5 mm, preferably at most
approximately 1.0 mm, in particular at most approximately 0.9 mm,
for example approximately 0.8 mm.
[0098] By way of example a spacing between a sealing edge which is
an inner sealing edge in the axial direction and a recess adjoining
said sealing edge in a manner directed inwardly in the axial
direction can be at least approximately 0.5 mm, preferably at least
approximately 0.6 mm. Furthermore, a spacing between a sealing edge
which is an inner sealing edge in the axial direction and a recess
adjoining this sealing edge in a manner directed inwardly in the
axial direction can be at most approximately 2.5 mm, preferably at
most approximately 1.0 mm, in particular at most approximately 0.9
mm, for example approximately 0.8 mm.
[0099] The recess which adjoins a sealing edge in a manner directed
inwardly in the axial direction is in particular an undercut that
has an effect when removing the sealing element from an injection
mold.
[0100] A spacing between a sealing edge and a recess adjoining said
sealing edge in a manner directed inwardly in the axial direction
is in particular a flank length of the sealing edge.
[0101] By way of example, the flank lengths of adjacent sealing
edges of a sealing lip or all sealing lips differ from one another
by at most approximately 15%, preferably at most approximately
5%.
[0102] It can be favorable if a flank length of the sealing edge
which is an inner sealing edge in the axial direction is smaller
than a flank length of the sealing edge which is an outer sealing
edge in the axial direction, for example by at least 0.05 mm, in
particular at least approximately 0.1 mm, and/or by at most
approximately 0.2 mm, in particular at most approximately 0.15 mm.
In this way, the radial force can temporarily load the primary
sealing edge more heavily for example as the sealing element is
demolded. The primary sealing edge is arranged further outwardly in
the axial direction and is more flexible than the secondary sealing
edge, which is an inner sealing edge in the axial direction. In
spite of the temporarily heavier loading, the primary sealing edge
is therefore preferably at a lower risk of being plastically
deformed.
[0103] It can also be provided that a flank length of the sealing
edge which is an outer sealing edge in the axial direction is
smaller than a flank length of the sealing edge which is an inner
sealing edge in the axial direction, for example by at least
approximately 0.05 mm, in particular at least approximately 0.1 mm,
and/or by at most approximately 0.2 mm, in particular at most
approximately 0.15 mm.
[0104] A sealing edge angle which is enclosed on the one hand by a
flank of a sealing edge adjoining said sealing edge in a manner
directed inwardly in the axial direction and on the other hand by
an axis of symmetry of the sealing element is preferably of at
least roughly equal size for each sealing edge.
[0105] The sealing edge angles of adjacent sealing edges of a
sealing lip or all sealing lips preferably differ from one another
by at most approximately 15%, preferably at most approximately
5%.
[0106] A sealing edge which is an outer sealing edge in the axial
direction is preferably a primary sealing edge.
[0107] A sealing edge which is an inner sealing edge in the axial
direction is preferably a secondary sealing edge, in particular if
no further sealing edge is arranged between the outer sealing edge
and the inner sealing edge.
[0108] By suitable selection of the flank lengths and/or the
sealing edge angles, the radial load, which weighs on both sealing
edges, during the demolding is preferably distributed uniformly and
for a longer time over both sealing edges. Both sealing edges are
thus preferably simultaneously raised and lowered again during the
demolding.
[0109] A diameter of the movable component is preferably at least
approximately 4 mm, for example at least approximately 5 mm, and/or
at most approximately 18 mm, for example at most approximately 13
mm.
[0110] The movable component is in particular a piston rod.
[0111] It has surprisingly been found that smaller radii at the
sealing edges are more sensitive to forced demolding than larger
radii. Accordingly, larger radii are more easily demolded than
smaller radii. As a result of the demolding, the sealing edges
experience a certain plastic deformation, since the temperature
prevailing during the demolding is high and the material at this
temperature often does not have a sufficiently high strength to
fully maintain its shape. The radii can then be distorted by
plastic deformation.
[0112] A reliable sealing effect alongside good demolding behavior
is provided in particular if the following parameters are
observed:
[0113] a sealing edge radius of a sealing edge which is an inner
sealing edge in the axial direction is preferably at least
approximately 0.1 mm, in particular at least approximately 0.15 mm,
for example approximately 0.2 mm;
[0114] a sealing edge radius of a sealing edge which is an inner
sealing edge in the axial direction is preferably at most
approximately 0.5 mm, in particular at most approximately 0.25
mm;
[0115] a sealing edge radius of a sealing edge which is an outer
sealing edge in the axial direction is preferably at least
approximately 0.1 mm, in particular at least approximately 0.15 mm,
for example approximately 0.2 mm;
[0116] a sealing edge radius of a sealing edge which is an outer
sealing edge in the axial direction is preferably at most
approximately 0.5 mm, in particular at most approximately 0.25
mm;
[0117] a radius of curvature of an indentation which is an inner
indentation in the axial direction is preferably at least
approximately 0.1 mm, in particular at least approximately 0.15 mm,
for example approximately 0.2 mm;
[0118] a radius of curvature of an indentation (between two sealing
edges) which is an outer indentation in the axial direction is
preferably at most approximately 0.3 mm, in particular at most
approximately 0.25 mm.
[0119] The sealing lip geometries that have proved their worth in
sealing systems of fuel pumps can prove to be too stable and/or too
stiff to be satisfactorily demolded, in particular with the use of
fluoro-thermoplastics which can be injection molded on account of
the higher rigidity compared to materials based on PTFE.
[0120] It has proven to be advantageous if a sealing lip thickness
at a narrowest point on an inner side of a sealing edge which is an
inner sealing edge in the axial direction is at least approximately
0.4 mm, preferably at least approximately 0.5 mm, for example
approximately 0.6 mm.
[0121] It can also be provided that a sealing lip thickness at a
narrowest point on an inner side of a sealing edge which is an
inner sealing edge in the axial direction is at most approximately
1.0 mm, preferably at most approximately 0.7 mm.
[0122] It can be favorable if a sealing lip thickness at a
narrowest point between a sealing edge which is an inner sealing
edge in the axial direction and a sealing edge which is an outer
sealing edge in the axial direction is at least approximately 0.3
mm, preferably at least approximately 0.4 mm, for example
approximately 0.5 mm.
[0123] It can also be provided that a sealing lip thickness at a
narrowest point between a sealing edge which is an inner sealing
edge in the axial direction and a sealing edge which is an outer
sealing edge in the axial direction is at most approximately 0.9
mm, preferably at most approximately 0.6 mm.
[0124] It has been found that, in particular with the use of the
preferred material, on account of the higher rigidity and strength,
the described thicknesses can be sufficient for example to reliably
seal the pressures of a fuel pump prevailing during operation. In
addition, the described thicknesses can be necessary to be able to
demold the sealing element without causing any damage.
[0125] A sealing lip angle is preferably an angle which is enclosed
on the one hand by a surface or upper side of a sealing lip facing
away from at least one sealing edge and on the other hand by the
axis of symmetry.
[0126] In a completed state of the main body, in which this is
ready in particular to receive and/or fix one or more, in
particular two, spring elements, a sealing lip angle of one or both
sealing lips is for example at least approximately 2.degree.,
preferably at least approximately 3.degree., in particular
approximately 5.degree..
[0127] In a completed state of the main body, in which this is
ready in particular to receive and/or fix one or more, in
particular two, spring elements, a sealing lip angle of one or both
sealing lips is for example at most approximately 12.degree.,
preferably at most approximately 10.degree., in particular
approximately 8.degree..
[0128] The completed state of the main body, in which this is ready
in particular to receive and/or fix one or more, in particular two,
spring elements, is followed, preferably once the one or more, in
particular two, spring elements has/have been received and/or
fixed, by an assembly-ready state of the sealing element, in which
the sealing element is completed and is prepared for installation
in a device.
[0129] In the assembly-ready state of the sealing element, a
sealing lip angle is greater than in the completed state of the
main body, preferably by at least approximately 1.degree., for
example at least approximately 2.degree., in particular
approximately 3.degree., in particular on account of the effect of
the spring element.
[0130] In the assembly-ready state of the sealing element, a
sealing lip angle is greater than in the completed state of the
main body, preferably by at most approximately 10.degree., for
example at most approximately 6.degree., in particular
approximately 3.degree., in particular on account of the effect of
the spring element.
[0131] A reduction of the sealing lip angle reduces the radial
force during demolding, since a smaller undercut between shaping
device and sealing element is achieved by the straightening of the
sealing lip. If the angle is changed to 0.degree. (inner contour of
the sealing lip parallel to the axis; the surface or upper side of
a sealing lip facing away from the at least one sealing edge is
parallel to the axis of symmetry), the overlap of the sealing
element with the movable component is thus smaller, as is the
radial force with the same spring element.
[0132] If the main body for example in a first step, in particular
in an injection molding step, obtains a first shape, with which the
sealing lip angle is approximately 3.degree. or less, it can be
necessary to subject the main body to a finishing operation.
[0133] A post-treatment of the sealing lip (also referred to as
calibration of the sealing lip) can be necessary, for example after
the injection molding step, in particular in order to achieve a
necessary overlap and/or pressing effect of the sealing lips or
sealing edges with or against the movable component.
[0134] Such a post-treatment can be carried out cold or also
preferably at an increased temperature, in particular so as to
counteract a shape-memory effect for example with the use of
fluoropolymers.
[0135] In particular with the use of the sealing element as a fuel
pump seal, the sealing lips preferably each have two or more
sealing edges.
[0136] Recesses which are intended to promote the lubrication of
the sealing element are preferably formed between the sealing
edges.
[0137] These recesses thus serve preferably as lubrication stores
and should be able to receive sufficient volumes so as to be able
to maintain the lubrication and/or so as to be able to momentarily
store a certain amount of fuel or engine oil in the event of
temporarily higher leaks. Deep recesses offer a larger storage
space, but can also hinder demolding if the sealing element for
example is produced in an injection molding process.
[0138] In particular, deep recesses can lead to severe plastic
deformation of the sealing edges during demolding.
[0139] The depth of a recess is preferably a height difference
between a sealing edge and a recess adjoining this sealing edge in
a manner directed inwardly in the axial direction.
[0140] Here, the height difference is in particular a spacing along
a direction running at right angles to an upper side or surface of
the sealing lip facing away from the at least one sealing edge.
[0141] It can be advantageous if a height difference between a
sealing edge and a recess adjoining this sealing edge in a manner
directed inwardly in the axial direction is at least approximately
0.1 mm, preferably at least approximately 0.15 mm, for example at
least approximately 0.2 mm.
[0142] It can also be favorable if a height difference between a
sealing edge and a recess adjoining this sealing edge in a manner
directed inwardly in the axial direction is at most approximately
0.4 mm, preferably at most approximately 0.3 mm, for example at
most approximately 0.25 mm.
[0143] The height difference can also be referred to as a storage
depth.
[0144] All of the described features and advantages of a sealing
lip or sealing edge can relate both to the sealing lip(s) and/or
the sealing edge(s) of the static sealing portion and to the
sealing lip(s) and/or the sealing edge(s) of the dynamic sealing
portion.
[0145] The sealing lips of the static sealing portion are
preferably formed mirror-symmetrically to one another with respect
to a transverse central plane running at right angles to the axis
of symmetry.
[0146] The sealing lips of the dynamic sealing portion are
preferably formed mirror-symmetrically to one another with respect
to a transverse central plane running at right angles to the axis
of symmetry.
[0147] The sealing lips of the dynamic sealing portions act
preferably in directions opposite one another.
[0148] All sealing edges of both sealing lips of the dynamic
sealing portions protrude and/or act preferably in a manner
directed inwardly in the radial direction.
[0149] The sealing element is in particular a double-acting sealing
element.
[0150] The thermoplastic material preferably is producible or is
produced as follows:
[0151] It can be favorable if the thermoplastic material is a
compound material which in particular is producible or is produced
by means of a compounding facility.
[0152] The compounding facility preferably comprises an extruder,
in particular a screw extruder, for example a twin-screw
extruder.
[0153] In particular the screw speed, screw geometry, mixing ratio
of the starting materials, and a temperature profile must be
accurately controlled by means of open-loop and/or closed-loop
control in order to ensure the desired material parameters.
[0154] In order to produce the thermoplastic material, one or more
of the following processing conditions, in particular all of the
following processing conditions, are preferably observed:
TABLE-US-00001 Parameter Unit Value Raw material 1 - Fluoropolymer
% 94 Raw material 2 - Carbon fiber % 4 Raw material 3 - Graphite %
2 Screw diameter mm 25 Ratio of length to diameter -- 42
Temperatures in the successive zones of the plasticizing unit: C1
.degree. C. 80 .+-. 20 C2 .degree. C. 340 .+-. 20 C3 .degree. C.
360 .+-. 20 C4 .degree. C. 365 .+-. 20 C5 .degree. C. 350 .+-. 20
C6 .degree. C. 340 .+-. 20 Screw speed rpm 180 .+-. 40 Mass
pressure bar 12 .+-. 6 Mass temperature .degree. C. 360 .+-. 20
(Temperature at the exit of the extruder) Mass throughput kg/h 15
.+-. 5 Extraction speed m/min 15 .+-. 5
[0155] It can be favorable if a fluoropolymer content of the
thermoplastic material, in respect of its mass and/or its volume,
is at least approximately 85%, preferably at least approximately
90%, for example approximately 94%.
[0156] It can also be provided that a fluoropolymer content of the
thermoplastic material, in respect of its mass and/or its volume,
is at most approximately 99%, preferably at most approximately 96%,
for example approximately 94%.
[0157] It can be favorable if a carbon fiber content of the
thermoplastic material, in respect of its mass and/or its volume,
is at least approximately 0.5%, preferably at least approximately
2%, for example approximately 4%.
[0158] It can also be provided that a carbon fiber content of the
thermoplastic material, in respect of its mass and/or its volume,
is at most approximately 10%, preferably at most approximately 6%,
for example approximately 4%.
[0159] It can be favorable if a graphite content of the
thermoplastic material, in respect of its mass and/or its volume,
is at least approximately 0.5%, preferably at least approximately
1.5%, for example approximately 2%.
[0160] It can also be provided that a graphite content of the
thermoplastic material, in respect of its mass and/or its volume,
is at most approximately 6%, preferably at most approximately 4%,
for example approximately 2%.
[0161] The thermoplastic material obtained in the described way is
preferably used to produce one or more sealing elements.
[0162] The thermoplastic material is for this purpose further
processed, in particular is brought into a desired shape in an
injection molding process, whilst retaining one or more of the
following processing conditions, in particular all of the following
processing conditions:
TABLE-US-00002 Parameter Unit Value Material name -- VM3050 Screw
diameter mm 25 Temperatures in the successive zones of the
plasticizing unit: C1 .degree. C. 350 .+-. 20 C2 .degree. C. 365
.+-. 20 C3 .degree. C. 370 .+-. 20 C4 .degree. C. 375 .+-. 20 C5
.degree. C. 380 .+-. 20 Mold temperature .degree. C. 245 .+-. 20
Plasticizing volume cm.sup.3 15.6 Injection rate cm.sup.3/s 30
Injection pressure bar 1200 .+-. 100 Holding pressure bar 160
Holding pressure time s 6 Residual cooling time s 15
[0163] The prominent properties of this thermoplastic material,
called VM3050 in the present case, when used for the production of
sealing elements are detailed in the table below in comparison with
other materials:
TABLE-US-00003 Properties Test item PTFE compound VM3050 VM3044
VM3006 Processing -- pressing, sintering thermoplastic
thermoplastic thermoplastic (for example (for example (for example
injection injection injection molding) molding) molding) Filler
content -- carbon fiber: 10% carbon fiber: 4% PI: 20% PEEK: 30%
graphite: 5% graphite: 2% carbon fiber: 10% graphite: 10% Colour --
black black yellow black Wear (bearing Seal 0.32 mm 0.41 mm 0.69 mm
0.47 mm surface) Leak Seal 4 mm.sup.3/min 0.9 mm.sup.3/min 150
mm.sup.3/min 500 mm.sup.3/min Radial force Seal without 120 .+-. 10
N 220 .+-. 10 N 70 .+-. 10 N 90 .+-. 10 N (original) spring Radial
force Seal without 90 .+-. 10 N 130 .+-. 10 N 40 .+-. 10 N 80 .+-.
10 N after thermal spring conditioning Radial force Seal with 190
.+-. 10 N 250 .+-. 10 N 125 .+-. 10 N 130 .+-. 10 N (original)
spring Radial force Seal with 155 .+-. 10 N 170 .+-. 10 N 100 .+-.
10 N 125 .+-. 10 N after thermal spring conditioning
[0164] The terms "approximately" or "roughly" preferably denote a
maximum deviation of at most 10%, in particular at most 5%, for
example at most 1%, of the specified value.
[0165] Further preferred features and/or advantages of the
invention are the subject of the following description and the
representation in the drawings of exemplary embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
[0166] FIG. 1 shows a schematic longitudinal section through a main
body of a sealing element, wherein the main body has its final
outer shape only in part;
[0167] FIG. 2 shows a schematic illustration, corresponding to FIG.
1, of the main body, wherein the main body has been processed to
complete an outer contour;
[0168] FIG. 3 shows a schematic illustration, corresponding to FIG.
1, of a sealing element which comprises the completed main body and
two spring elements;
[0169] FIG. 4 shows a schematic longitudinal section through a
sealing lip of a sealing element, in which a middle portion is
provided with a guide portion;
[0170] FIG. 5 shows an illustration, corresponding to FIG. 4, of a
sealing lip of a sealing element, wherein the sealing element does
not comprise a guide portion;
[0171] FIG. 6 shows an illustration, corresponding to FIG. 4, of a
sealing lip in order to illustrate radii of the sealing edges of
the sealing lip and also radii of recesses in the sealing lip;
[0172] FIG. 7 shows an illustration, corresponding to FIG. 4, of a
sealing lip in order to illustrate a sealing lip thickness;
[0173] FIG. 8 shows an illustration, corresponding to FIG. 4, of a
sealing lip in order to illustrate a sealing lip angle; and
[0174] FIG. 9 shows an illustration, corresponding to FIG. 4, of a
sealing lip in order to illustrate undercut depths and a storage
depth of a store of the sealing lip.
[0175] In all Figures, like or functionally equivalent elements are
provided with the same reference signs.
DETAILED DESCRIPTION OF THE DRAWINGS
[0176] An embodiment illustrated in FIGS. 1 to 3 of a sealing
element denoted as a whole by 100 is, for example, part of a
high-pressure pump 102 and serves to provide a seal between two
media spaces 104 in the region of a movable component 106.
[0177] The movable component 106 can be a piston of the
high-pressure pump 102, for example.
[0178] The movable component 106 is in particular guided through
the sealing element 100.
[0179] Here, both the movable component 106 and the sealing element
100 are preferably rotationally symmetrical about an axis of
symmetry 108.
[0180] The axis of symmetry 108 is in particular oriented parallel
to a longitudinal axis 110 of the movable component 106 and of the
sealing element 100.
[0181] The sealing element 100 and the movable component 106 have a
common axis of symmetry 108 in the assembled state.
[0182] The longitudinal axis 110 preferably defines an axial
direction 112.
[0183] A direction oriented at right angles to the axial direction
112 is a radial direction 114.
[0184] The media spaces 104 are preferably separated from one
another in the axial direction 112 by means of the sealing element
100.
[0185] The sealing element 100 preferably borders the movable
component 106 in the radial direction 114 in an inwardly directed
manner by means of two dynamic sealing portions 116.
[0186] The sealing element 100 borders a housing 118 of the
high-pressure pump 102 in an outwardly directed manner in the
radial direction 114.
[0187] The sealing element 100, in the assembled state, is fixed
relative to the housing 118.
[0188] Two sealing regions 120 of the sealing element 100
associated with the two media spaces 104 thus comprise, in addition
to the dynamic sealing portions 116, also two static sealing
portions 122 bearing against the housing 118.
[0189] The dynamic sealing portions 116 serve to provide the
dynamic seal between the sealing element 100 and the component 106
moving relative to the sealing element 100, in particular
displaceable along the axial direction 112.
[0190] In order to attain an increased sealing effect, one or more
spring elements 124 of the sealing element 100 can be provided.
[0191] The one or more spring elements 124 in particular are
arrangable or arranged in one or more spring element receptacles
126.
[0192] In particular, one or more dynamic sealing portions 116 are
pressable against the movable component 106 by means of the one or
more spring elements 124.
[0193] Alternatively or additionally hereto, it can be provided
that one or more static sealing portions 122 are pressable against
a housing 118 of the high-pressure pump 102 by means of the one or
more spring elements 124.
[0194] A spring element 124 is in particular annular, for example
circular ring-shaped, and for example has a V-shaped or U-shaped
cross-section.
[0195] Each dynamic sealing portion 116 preferably comprises a
sealing lip 127 having one, two or more than two sealing edges
128.
[0196] Each sealing lip 127 and/or each sealing edge 128 is
preferably substantially annular and substantially rotationally
symmetrical about the axis of symmetry 108.
[0197] The sealing edges 128 of each sealing lip 127 are arranged
here preferably at different spacings from a transverse central
plane 130 of the sealing element 100 running at right angles to the
longitudinal axis 110 of the sealing element 100.
[0198] The sealing element 100 in particular comprises a main body
132, which is formed preferably in one piece from a thermoplastic
material.
[0199] The main body 132 in particular comprises one or more
dynamic sealing portions 116, one or more static sealing portions
122, and one or more spring element receptacles 126.
[0200] The main body 132 by way of example can be produced as
follows.
[0201] By way of example, a blank 134 of the main body 132 can be
produced in an injection molding process.
[0202] The blank 134 of the main body 132 at this point has its
final outer shape only in portions.
[0203] In particular, merely the spring element receptacles 126 are
completed at the time of production of the blank 134.
[0204] By contrast, the sealing portions 116, 122 must be subjected
to finishing in order to complete the main body 132, in particular
by machining, for example CNC processing.
[0205] As is clear in particular from a comparison of FIGS. 1 to 3,
an outer contour can first be processed by way of example, in order
to complete the radially outer static sealing portions 122. A
radially inner processing can then be performed in order to
complete the dynamic sealing portions 116.
[0206] Alternatively, it can be provided that the blank 134 is
produced for example in an injection molding method in such a way
that both the static sealing portions 122 and the spring element
receptacles 126 already have the final outer shape after the
execution of the injection molding process.
[0207] Merely the radially inner region then still has to be
subjected to a mechanical finishing operation in order to complete
the dynamic sealing portions 116.
[0208] In particular, the main body 132 and thus the entire sealing
element 100 can be produced particularly efficiently and
economically by a combination of production of the blank 134 in a
high-pressure process and/or a high-temperature process, for
example an injection molding process, on the one hand and only
partial subsequent processing in order to complete the main body
132 on the other hand.
[0209] FIG. 4 shows an enlarged sectional illustration of a sealing
lip 127 of a dynamic sealing portion 116 of an alternative
embodiment of a sealing element 100.
[0210] The sealing lip 127 of this sealing element 100 differs from
the sealing lip 127 of the embodiment of the sealing element 100
illustrated in FIG. 3 fundamentally by its geometry.
[0211] In order to explain the geometry of the sealing lip 127 in
greater detail, the individual components and region of the sealing
lip 127 will first be explained in greater detail:
[0212] The sealing lip 127 is formed by a portion of the main body
132 running at a slight incline relative to the axial direction 112
from a middle portion 140 of the main body 132 and protruding
slightly inwardly in the radial direction 114. Here, the sealing
lip 127 comprises an underside 142 facing towards the movable
component 116 in the assembled state of the sealing element 100 and
also an upper side 144 facing away from the movable component 106
in the assembled state of the sealing element 100.
[0213] The upper side 144 is substantially flat in cross-section.
When the sealing element 100 is observed three-dimensionally, the
upper side 144 in particular has a lateral shape in the form of a
truncated cone.
[0214] One or more, for example two, protrusions 146 is/are
provided on the underside 142 of the sealing lip 127.
[0215] These protrusions 146 form the sealing edges 128 of the
sealing lip 127 at their ends protruding inwardly in the radial
direction 114.
[0216] The sealing edges 128 are each adjoined by a flank 148
directed inwardly in the axial direction 112, that is to say in the
direction of the middle portion 140 of the main body 132.
[0217] A recess 150 or indentation 152 of the sealing lip 127 is
provided on a side of each flank 148 facing away from the
corresponding sealing edge 128.
[0218] In particular, a recess 150 is thus provided between the two
protrusions 146 forming the sealing edge 128.
[0219] A further recess 150 is preferably formed between the
sealing edge 128i, which is an inner sealing edge in the axial
direction, and the middle portion 140 of the main body 132.
[0220] As can be derived from FIG. 4, the middle portion 140 of the
main body 132 can comprise a guide portion 154. This guide portion
154 preferably has a surface running parallel to the axis of
symmetry 108 and serves to support and/or guide the movable
component 106 in the case of a sideward movement of the movable
component 106 in the state of use of the sealing element 100.
[0221] A spacing of the guide portion 154 from the axis of symmetry
108 is preferably greater here than a radius R.sub.B of the movable
component 106.
[0222] The outer sealing edge 128a of the sealing lip 127 forms a
primary sealing edge 128.
[0223] The inner sealing edge 128i of the sealing lip 127 forms a
secondary sealing edge 128.
[0224] As can be derived from FIG. 4, the outer sealing edge 128a
and the recess 150 adjoining this outer sealing edge 128a in a
manner directed inwardly in the axial direction 112 have an axial
spacing A.sub.aa from one another, which for example corresponds at
least roughly to an axial spacing A.sub.ai between the inner
sealing edge 128i and the recess 150 adjoining this inner sealing
edge 128i in a manner directed inwardly in the axial direction
112.
[0225] The spacing A.sub.aa is preferably between approximately 0.5
mm to approximately 2.5 mm, for example between approximately 0.5
mm to approximately 1.5 mm, in particular between approximately 0.6
mm to approximately 1 mm.
[0226] Both the spacing A.sub.aa and the spacing A.sub.ai are
preferably based on the spacing of the relevant parts of the
sealing lip 127 from one another in the axial direction 112.
[0227] By suitable selection of the spacings A.sub.aa and A.sub.ai,
the sealing element 100 can be removed with minimal damage from a
molding device (not illustrated), for example in the case of
production of said sealing element in an injection molding method.
In particular, the sealing lip 127 can be bent outwardly in the
radial direction 114 in the region of the outer sealing edge 128a
during the demolding process so as to also enable a demolding of
the protrusion 146 forming the inner sealing edge 128i with minimal
destruction.
[0228] During the demolding, the outer sealing edge 128a and the
inner sealing edge 128i are preferably moved outwardly in the
radial direction 114 substantially evenly. The forces acting as a
result on the sealing lip 127 can then preferably be transferred
and taken up evenly.
[0229] An alternative embodiment of a sealing lip 127 of a sealing
element 100 illustrated in FIG. 5 differs from the embodiment
illustrated in FIG. 4 fundamentally in that the middle portion 140
does not have a guide portion 154.
[0230] A spacing A.sub.m between the middle portion 140 and the
movable component 106 in the assembled state of the sealing element
100 is consequently greater than in the embodiment of the sealing
element 100 illustrated in FIG. 4.
[0231] For the rest, the embodiment illustrated in FIG. 5 coincides
in terms of structure and function with the embodiment illustrated
in FIG. 4, and therefore reference is made to the above description
of FIG. 4 in this regard.
[0232] In FIG. 6 radii R of the sealing edges 128 and of the
recesses 150 are illustrated. The selection of the suitable radii
in particular influences a demolding of the sealing element 100
after production thereof in an injection molding method.
[0233] The radii R of the sealing edges 128 and of the recesses 150
are preferably selected to be at least roughly of similar size.
[0234] By way of example, the radii are between approximately 0.1
mm and approximately 0.5 mm, in particular approximately 0.2
mm.
[0235] However, radii R different from one another can also be
provided.
[0236] By way of example, the radii R of the sealing edges 128 can
be larger or smaller than the radii R of the recesses 150.
[0237] As can be derived in particular from FIG. 7, the sealing lip
127 is preferably formed so that a sealing lip thickness D.sub.1 in
the region of the recess 150 or indentation 152 between the middle
portion 140 and the flank 148 of the inner sealing edge 128i is
greater than a sealing lip thickness D.sub.2 between the two
sealing edges 128i, 128a in the region of the recess 150 or
indentation 152 arranged therebetween.
[0238] The sealing lip thickness D.sub.1, D.sub.2 is in each case a
minimum spacing between the upper side 144 of the sealing lip 127
and the corresponding recess 150 or indentation 152.
[0239] It can be provided that the sealing lip thickness D.sub.1 by
way of example is between approximately 0.4 mm to approximately 1
mm, in particular between approximately 0.5 mm to approximately 0.7
mm, preferably approximately 0.6 mm.
[0240] It can also be provided that the sealing lip thickness
D.sub.2 is between approximately 0.3 mm to approximately 0.7 mm, in
particular is approximately 0.5 mm.
[0241] The sealing lip 127 is in particular formed here so that an
optimal seal at the movable component 106 is ensured if this
movable component 106 by way of example has a radius R.sub.B
between approximately 2 mm to 9 mm, in particular approximately 2.5
mm to approximately 6.5 mm.
[0242] As can be derived in particular from FIG. 8, the sealing lip
127 protrudes away from the middle portion 140 of the main body 132
of the sealing element 100 at an incline relative to the axial
direction 112 and at an incline relative to the radial direction
114.
[0243] A sealing lip angle .alpha., which is enclosed on the one
hand by the upper side 144 of the sealing lip 127 and on the other
hand by the axis of symmetry 108, in the completed state of the
main body 132 prior to the assembly of a spring element 124 is
preferably between approximately 3.degree. and approximately
10.degree.. In a state of the sealing element 100 ready for
assembly, i.e. following the assembly of the spring elements 124,
the sealing lip angle .alpha. can be greater, for example by
approximately 1.degree. to 3.degree..
[0244] It can be provided that the sealing lip angle .alpha. during
production of the main body 132 is initially selected to be
smaller. By way of example, when producing the main body 132 in an
injection molding method, a sealing lip angle .alpha. of 0.degree.
can be provided initially. The upper side 144 of the sealing lip
127 then runs substantially parallel to the axis of symmetry
108.
[0245] In order to ensure an optimal sealing effect of the sealing
element 100, a finishing operation or post-treatment of the main
body 132 is then preferably performed after the production of the
main body 132 in the injection molding method.
[0246] In particular, it can be provided here that the sealing lip
127 is reshaped by cold deformation or deformation after or during
a heating of the sealing lip 127 and/or of the entire main body
132, in particular so as to obtain a sealing lip angle .alpha. of
more than approximately 3.degree..
[0247] In FIG. 9 undercut depths T are illustrated, which, on
account of the geometry of the sealing lip 127, have to be overcome
when demolding the sealing element 100. An undercut depth T between
the two sealing edges 128 is here preferably smaller than an
undercut depth T in the region of the middle portion 140 of the
main body 132 and/or than in the region of a recess 150 and/or
indentation 152 arranged between the middle portion 140 and the
flank 148 of the inner sealing edge 128i.
[0248] Due to the fact that the undercut depths T have to be
overcome, the de-molding of the sealing element 100 from an
injection mold is in particular a forced demolding.
[0249] As can also be derived from FIG. 9, the sealing lip 127
preferably has a store 156 for receiving a medium, for example fuel
or engine oil. By means of the store 156, in particular a leak of
the sealing element in the region of the sealing lip 127 can be
compensated for at least temporarily in that the medium guided past
the outer sealing edge 128a is received in the store 156. By
suitable geometry of the sealing edges 128 and/or the flanks 148,
the received medium can be recovered into the adjacent media space
104 little by little, in particular with an axial movement of the
movable component 106.
[0250] A storage depth T.sub.D is preferably a minimal spacing
between the recess 150 between the two sealing edges 128 and a
straight line running through the two sealing edges 128.
[0251] The storage depth T.sub.D is preferably between
approximately 0.1 mm to approximately 0.4 mm, in particular between
approximately 0.15 mm and approximately 0.25 mm.
[0252] The parameters of a sealing lip 127 described with regard to
FIGS. 4 to 9 preferably apply to a sealing lip 127 of a dynamic
sealing portion 116 of the sealing element 100. It can also be
provided that the described values and parameters apply for both
sealing lips 127 of both dynamic sealing portions 116.
[0253] In particular, it can be provided that the sealing element
100 in all described embodiments is mirror-symmetrical with respect
to the transverse central plane 130.
[0254] The sealing element 100 is preferably also rotationally
symmetrical about the axis of symmetry 108 in each described
embodiment.
[0255] Preferred embodiments can be the following.
[0256] 1. Sealing element (100) for providing a seal between a
first media space (104) filled with a first medium and a second
media space (104) filled with a second medium in the region of a
movable component (106), which is guided or guidable through the
sealing element (100) displaceably along a longitudinal axis (110)
of the movable component (106) and/or rotatably along the
longitudinal axis (110),
[0257] wherein the sealing element (100) comprises a main body
(132), which has two dynamic sealing portions (116) which abut or
are abuttable against the movable component (106),
[0258] wherein each dynamic sealing portion (116) has a sealing lip
(127), wherein each sealing lip (127) comprises one, two or more
sealing edges (128),
[0259] wherein the main body (132) is preferably formed from a
partially fluorinated or fully fluorinated thermoplastic material
and has obtained at least part of its final outer shape or only
part of its final outer shape in particular in a high-pressure
process and/or in a high-temperature process.
[0260] 2. Sealing element (100) according to embodiment 1,
characterized in that the main body (132) is an injection-molded
component and/or is formed from an injection-moldable partially
fluorinated or fully fluorinated thermoplastic material.
[0261] 3. Sealing element (100) according to either one of
embodiments 1 or 2, characterized in that a spacing (A) between a
sealing edge (128) which is an outer sealing edge in the axial
direction (112) and a recess adjoining this sealing edge (128) in a
manner directed inwardly in the axial direction (112) is at least
approximately 0.5 mm, preferably at least approximately 0.6 mm.
[0262] 4. Sealing element (100) according to any one of embodiments
1 to 3, characterized in that a spacing (A) between a sealing edge
(128) which is an outer sealing edge in the axial direction (112)
and a recess (150) adjoining this sealing edge (128) in a manner
directed inwardly in the axial direction (112) is at most
approximately 1.5 mm, preferably at most approximately 1.0 mm, in
particular at most approximately 0.9 mm, for example approximately
0.8 mm.
[0263] 5. Sealing element (100) according to any one of embodiments
1 to 4, characterized in that a spacing (A) between a sealing edge
(128) which is an inner sealing edge in the axial direction (112)
and a recess (150) adjoining this sealing edge (128) in a manner
directed inwardly in the axial direction (112) is at least
approximately 0.5 mm, preferably at least approximately 0.6 mm.
[0264] 6. Sealing element (100) according to any one of embodiments
1 to 5, characterized in that a spacing (A) between a sealing edge
(128) which is an inner sealing edge in the axial direction (112)
and a recess (150) adjoining this sealing edge (128) in a manner
directed inwardly in the axial direction (112) is at most
approximately 2.5 mm, preferably at most approximately 1.0 mm, in
particular at most approximately 0.9 mm, for example approximately
0.8 mm.
[0265] 7. Sealing element (100) according to any one of embodiments
1 to 6, characterized in that two flank lengths of adjacent sealing
edges (128) of a sealing lip (127) or all sealing lips (127) differ
from one another by at most approximately 15%, preferably at most
approximately 5%.
[0266] 8. Sealing element (100) according to any one of embodiments
1 to 7, characterized in that a flank length of a sealing edge
(128) which is an inner sealing edge in the axial direction (112)
is smaller than a flank length of a sealing edge (128) which is an
outer sealing edge in the axial direction (112), for example by at
least approximately 0.05 mm, in particular at least approximately
0.1 mm, and/or by at most approximately 0.2 mm, in particular at
most approximately 0.15 mm.
[0267] 9. Sealing element (100) according to any one of embodiments
1 to 8, characterized in that a flank length of a sealing edge
(128) which is an outer sealing edge in the axial direction (112)
is smaller than a flank length of a sealing edge (128) which is an
inner sealing edge in the axial direction (112), for example by at
least approximately 0.05 mm, in particular at least approximately
0.1 mm, and/or by at most approximately 0.2 mm, in particular at
most approximately 0.15 mm.
[0268] 10. Sealing element (100) according to any one of
embodiments 1 to 9, characterized in that a sealing edge angle
which is enclosed on the one hand by a flank (148) of the sealing
edge (128) adjoining a sealing edge (128) in a manner directed
inwardly in the axial direction (112) and on the other hand by an
axis of symmetry (108) of the sealing element (100), is at least
roughly of equal size preferably for each sealing edge (128),
wherein the sealing edge angles of adjacent sealing edges (128) of
a sealing lip (127) or of all sealing lips (127) differ from one
another preferably by at most approximately 15%, preferably at most
approximately 5%.
[0269] 11. Sealing element (100) according to any one of
embodiments 1 to 10, characterized in that a diameter of the
movable component (106) is preferably at least approximately 4 mm,
for example at least approximately 5 mm, and/or at most
approximately 18 mm, for example at most approximately 13 mm.
[0270] 12. Sealing element (100) according to any one of
embodiments 1 to 11, characterized in that a sealing edge radius of
a sealing edge (128) which is an inner sealing edge in the axial
direction (112) and/or a sealing edge radius of a sealing edge
(128) which is an outer sealing edge in the axial direction (112)
is at least approximately 0.1 mm, in particular at least
approximately 0.15 mm, for example approximately 0.2 mm.
[0271] 13. Sealing element (100) according to any one of
embodiments 1 to 12, characterized in that a sealing edge radius of
a sealing edge (128) which is an inner sealing edge in the axial
direction (112) and/or a sealing edge radius of a sealing edge
(128) which is an outer sealing edge in the axial direction (112)
are/is at most approximately 0.5 mm, in particular at most
approximately 0.25 mm.
[0272] 14. Sealing element (100) according to any one of
embodiments 1 to 13, characterized in that a sealing lip thickness
(D) at a narrowest point on an inner side of a sealing edge (128)
which is an inner sealing edge in the axial direction (112) is at
least approximately 0.4 mm, preferably at least approximately 0.5
mm, for example approximately 0.6 mm.
[0273] 15. Sealing element (100) according to any one of
embodiments 1 to 14, characterized in that a sealing lip thickness
(D) at a narrowest point on an inner side of a sealing edge (128)
which is an inner sealing edge in the axial direction (112) is at
most approximately 1.0 mm, preferably at most approximately 0.7
mm.
[0274] 16. Sealing element (100) according to any one of
embodiments 1 to 15, characterized in that a sealing lip thickness
(D) at a narrowest point between a sealing edge (128) which is an
inner sealing edge in the axial direction (112) and a sealing edge
(128) which is an outer sealing edge in the axial direction (112)
is at least approximately 0.3 mm, preferably at least approximately
0.4 mm, for example approximately 0.5 mm.
[0275] 17. Sealing element (100) according to any one of
embodiments 1 to 16, characterized in that a sealing lip thickness
(D) at a narrowest point between a sealing edge (128) which is an
inner sealing edge in the axial direction (112) and a sealing edge
(128) which is an outer sealing edge in the axial direction (112)
is at most approximately 0.9 mm, preferably at most approximately
0.6 mm.
[0276] 18. Sealing element (112) according to any one of
embodiments 1 to 17, characterized in that, in a completed state of
the main body (132), a sealing lip angle of one or both sealing
lips (127) is for example at least approximately 2.degree.,
preferably at least approximately 3.degree., in particular
approximately 5.degree..
[0277] 19. Sealing element (100) according to any one of
embodiments 1 to 18, characterized in that, in a completed state of
the main body (132), a sealing lip angle of one or both sealing
lips (127) is for example at most approximately 12.degree.,
preferably at most approximately 10.degree., in particular
approximately 8.degree..
[0278] 20. Sealing element (100) according to any one of
embodiments 1 to 19, characterized in that a height difference
between a sealing edge (128) and a recess adjoining said sealing
edge (128) in a manner directed inwardly in the axial direction
(112) and/or a storage depth of the sealing lip (127) is at least
approximately 0.1 mm, preferably at least approximately 0.15 mm,
for example at least approximately 0.2 mm.
[0279] 21. Sealing element (100) according to any one of
embodiments 1 to 20, characterized in that a height difference
between a sealing edge (128) and a recess adjoining said sealing
edge (128) in a manner directed inwardly in the axial direction
(112) and/or a storage depth of the sealing lip (127) is at most
approximately 0.4 mm, preferably at most approximately 0.3 mm, for
example at most approximately 0.25 mm.
[0280] 22. Sealing element (100), in particular according to any
one of embodiments 1 to 21, for providing a seal between a first
media space (104) filled with a first medium and a second media
space (104) filled with a second medium in the region of a movable
component (106), which is guided or guidable through the sealing
element (100) displaceably along a longitudinal axis (110) of the
movable component (106) and/or rotatably along the longitudinal
axis (110),
[0281] wherein the sealing element (100) comprises a main body
(132), which has two dynamic sealing portions (116) which abut or
are abuttable against the movable component (106),
[0282] wherein each dynamic sealing portion (116) has a sealing lip
(127), wherein each sealing lip (127) comprises one, two or more
sealing edges (128),
[0283] wherein the main body (132) is formed of a partially
fluorinated or fully fluorinated thermoplastic material which is
injection-moldable.
[0284] 23. Sealing element (100) according to any one of
embodiments 1 to 23, characterized in that the main body (132) of
the sealing element (100) has obtained at least part of its final
outer shape or only part of its final outer shape or its entire
final outer shape by means of turning and/or machining.
[0285] 24. Sealing element (100) according to any one of
embodiments 1 to 23, characterized in that an inner side or
underside (142) of the main body (132) facing towards the movable
component (106) in the mounted state of the sealing element (100)
is subjected to a finishing operation after a shaping step.
[0286] 25. Sealing element (100) according to any one of
embodiments 1 to 24, characterized in that a fluoropolymer content
of the thermoplastic material, in respect of its mass and/or its
volume, is at least approximately 85%, preferably at least
approximately 90%, for example approximately 94%.
[0287] 26. Sealing element (100) according to any one of
embodiments 1 to 25, characterized in that a fluoropolymer content
of the thermoplastic material, in respect of its mass and/or its
volume, is at most approximately 99%, preferably at most
approximately 96%, for example approximately 94%.
[0288] 27. Sealing element (100) according to any one of
embodiments 1 to 26, characterized in that a carbon fiber content
of the thermoplastic material, in respect of its mass and/or its
volume, is at least approximately 0.5%, preferably at least
approximately 2%, for example approximately 4%.
[0289] 28. Sealing element (100) according to any one of
embodiments 1 to 27, characterized in that a carbon fiber content
of the thermoplastic material, in respect of its mass and/or its
volume, is at most approximately 10%, preferably at most
approximately 6%, for example approximately 4%.
[0290] 29. Sealing element (100) according to any one of
embodiments 1 to 28, characterized in that a graphite content of
the thermoplastic material, in respect of its mass and/or its
volume, is at least approximately 0.5%, preferably at least
approximately 1.5%, for example approximately 2%.
[0291] 30. Sealing element (100) according to any one of
embodiments 1 to 29, characterized in that a graphite content of
the thermoplastic material, in respect of its mass and/or its
volume, is at most approximately 6%, preferably at most
approximately 4%, for example approximately 2%.
[0292] 31. High-pressure pump (102), comprising at least one
sealing element (100) according to any one of embodiments 1 to
30.
[0293] 32. Use of a high-pressure pump (102) according to
embodiment 31 for injecting a fuel into an internal combustion
engine.
[0294] 33. Use of a sealing element (100) according to any one of
embodiments 1 to 30 as a rod seal, piston seal and/or shaft seal,
in particular in a fuel pump and/or a piston pump.
[0295] 34. Use of a partially fluorinated or fully fluorinated
plastics material, which is injection-moldable, for producing a
sealing element (100), in particular a sealing element (100)
according to any one of embodiments 1 to 30.
[0296] 35. Method for producing a sealing element (100), in
particular a sealing element (100) according to any one of
embodiments 1 to 30, comprising:
[0297] producing a main body (132) of the sealing element (100)
from a partially fluorinated or fully fluorinated thermoplastic
material, wherein the main body (132) preferably obtains at least
part of its final outer shape or only part of its final outer shape
in particular in a high-pressure process and/or in a
high-temperature process.
[0298] 36. Method according to embodiment 35, characterized in that
the high-pressure process is an embossing process, a press molding
process, an injection molding process and/or a pressure diecasting
process.
[0299] 37. Method according to any one of embodiments 35 or 36,
characterized in that the high-temperature process comprises a hot
embossing process, a hot press molding process, an injection
molding process, a casting process, a sintering process and/or a
thermoforming process.
[0300] 38. Method according to any one of claims 35 to 37,
characterized in that the main body (132) of the sealing element
(100) is subjected to a finishing operation only in part after the
high-pressure process and/or the high-temperature process have/has
been performed.
[0301] 39. Method according to any one of embodiments 35 to 38,
characterized in that the main body (132) is machined and/or coated
fully or in part.
[0302] 40. Method according to any one of embodiments 35 to 39,
characterized in that one or more sealing portions (116, 122) of
the sealing element (100), in particular sealing edges (128),
is/are produced by mechanical processing, in particular machining,
of the main body (132).
[0303] 41. Method according to any one of embodiments 35 to 40,
characterized in that the main body (132), in an injection molding
step, obtains a first shape, with which a sealing lip angle of one
or both sealing lips (127) of the dynamic sealing portion (116) is
approximately 3.degree. or less.
[0304] 42. Method according to embodiment 41, characterized in that
the main body (132) is subjected to a post-treatment, in particular
a thermal and/or mechanical post-treatment, in such a way that the
sealing lip angle of one or both sealing lips (127) of the dynamic
sealing portion (116) is increased to more than approximately
3.degree., for example at least approximately 5.degree..
[0305] 43. Method, in particular according to any one of
embodiments 35 to 42, for producing a sealing element (100), in
particular a sealing element (100) according to any one of
embodiments 1 to 30, comprising:
[0306] producing a main body (132) of the sealing element (100)
from a partially fluorinated or fully fluorinated thermoplastic
material which is injection-moldable.
[0307] 44. Method according to any one of embodiments 35 to 43,
characterized in that the main body (132) of the sealing element
(100) obtains at least part of its final outer shape or only part
of its final outer shape or its entire final outer shape by means
of turning and/or machining.
[0308] 45. Method according to any one of embodiments 35 or 44,
characterized in that an inner side or underside (142) of the main
body (132) facing towards the movable component (106) in the
mounted state of the sealing element (100) is subjected to a
finishing operation after a shaping step.
[0309] 46. Method according to any one of embodiments 35 to 45,
characterized in that one or more sealing edges (128) and/or
indentations (152) and/or recesses (150) are formed and/or
subjected to a finishing operation by means of turning and/or
machining.
[0310] 47. Method according to embodiment 46, characterized in that
the turning and/or machining is performed with use of an axially
and radially movable tool, which is guided axially and radially
along the main body (100) in accordance with an inner contour of
said main body to be produced.
[0311] 48. Method according to any one of embodiments 46 or 47,
characterized in that the turning and/or machining is performed
with use of a tool which comprises a processing edge, in particular
a processing blade, complementary to the inner contour of the main
body (100) to be produced.
[0312] 49. Method according to embodiment 48, characterized in that
the tool is guided against the main body (100) from the inside out
in a radial direction, in particular in such a way that the desired
inner contour of the main body (132) is completed in a processing
step without axial movement.
[0313] 50. Method according to any one of embodiments 35 to 49,
characterized in that the thermoplastic material is produced as a
compound material from (according to weight and/or volume)
approximately 94% fluoropolymer, approximately 4% carbon fiber, and
approximately 2% graphite.
[0314] 51. Method according to any one of embodiments 35 to 50,
characterized in that the thermoplastic material is brought in
succession, in successive zones of a plasticizing unit of a
compounding facility, to the following temperatures:
80.+-.20.degree. C., 340.+-.20.degree. C., 360.+-.20.degree. C.,
365.+-.20.degree. C., 350.+-.20.degree. C., 340.+-.20.degree.
C.
[0315] 52. Method according to any one of embodiments 35 to 51,
characterized in that the thermoplastic material is brought in
succession, in successive zones of a plasticizing unit of an
injection molding facility for producing sealing elements (100), to
the following temperatures: 350.+-.20.degree. C., 365.+-.20.degree.
C., 370.+-.20.degree. C., 375.+-.20.degree. C., 380.+-.20.degree.
C.
* * * * *