U.S. patent application number 11/720465 was filed with the patent office on 2008-10-09 for control valve.
This patent application is currently assigned to SCHAEFFLER KG. Invention is credited to Jens Hoppe, Markus Kinscher, Martin Stief.
Application Number | 20080245324 11/720465 |
Document ID | / |
Family ID | 35645674 |
Filed Date | 2008-10-09 |
United States Patent
Application |
20080245324 |
Kind Code |
A1 |
Hoppe; Jens ; et
al. |
October 9, 2008 |
Control Valve
Abstract
A control valve (101) for the control of a hydraulic device for
changing the control times of gas exchange valves of an internal
combustion engine is provided, The control valve (101) is located
in a valve housing (106) and an elastic seal element (124) is
provided at an axial end thereof. The elastic seal element (124)
secures function by prevention of leakage flow between pressure
medium channels (113) and the pressure medium channels (113) and
the drain connector (T). Also provided is an elastic seal ring
(124) provided as a sealing ring with two conical regions (129,
131).
Inventors: |
Hoppe; Jens; (Erlangen,
DE) ; Stief; Martin; (Ottensoos, DE) ;
Kinscher; Markus; (Adelsdorf, DE) |
Correspondence
Address: |
VOLPE AND KOENIG, P.C.
UNITED PLAZA, SUITE 1600, 30 SOUTH 17TH STREET
PHILADELPHIA
PA
19103
US
|
Assignee: |
SCHAEFFLER KG
Herzogenaurach
DE
|
Family ID: |
35645674 |
Appl. No.: |
11/720465 |
Filed: |
November 8, 2005 |
PCT Filed: |
November 8, 2005 |
PCT NO: |
PCT/EP05/11899 |
371 Date: |
June 24, 2008 |
Current U.S.
Class: |
123/90.15 ;
277/641 |
Current CPC
Class: |
F01L 1/344 20130101;
F01L 1/3442 20130101; F01L 2001/34433 20130101; F01L 2001/34479
20130101; F01L 2001/34426 20130101 |
Class at
Publication: |
123/90.15 ;
277/641 |
International
Class: |
F01L 1/34 20060101
F01L001/34 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 7, 2004 |
DE |
10 2004 058 767.1 |
Claims
1. Sealing element comprising a sealing ring for sealing an axial
end of a control valve of a device for changing control times of
gas-exchange valves, including an inner casing surface and an outer
casing surface, the inner casing surface and the outer casing
surface are provided with a conical area on each of ring edges
thereof.
2. Sealing element according to claim 1, wherein the two conical
areas are formed on the ring edges of the sealing element offset
relative to each other in an axial direction.
3. Control valve for controlling a supply and discharge of pressure
medium to and from a device for changing control times of an
internal combustion engine with an essentially cylindrical valve
housing, on which pressure medium connections are formed and with
an axially displaceable control piston arranged within the valve
housing, wherein a connection between the pressure medium
connections can be established or separated as a function of a
position of the control piston, wherein the valve housing is
arranged within a valve receptacle, and wherein an insertion depth
of the valve housing into the valve receptacle is limited by an
axial stop formed in the valve receptacle, the axial stop is formed
as a circular or circular ring-shaped wall, which extends radially
inwards starting from an inner casing surface of the valve
receptacle, and a sealing element is arranged between the valve
housing and the axial stop of the valve receptacle.
4. Control valve according to claim 3, wherein an axial stop-side
end of the valve housing is formed with an area reduced in outer
diameter, wherein the sealing element is arranged at least
partially in the area reduced in outer diameter.
5. Control valve according to claim 3, wherein the sealing element
is constructed as a sealing ring with an outer casing surface and
an inner casing surface.
6. Control valve according to claim 3, wherein the sealing element
is comprised of an elastomer.
7. Control valve according to claim 3, wherein the elastomer is a
fluoro rubber or an acrylonitrile butadiene rubber.
8. Control valve according to claim 3, wherein the valve receptacle
is assembled from a first and a second bore, wherein the bores are
constructed in different surrounding constructions, arranged at
least approximately coaxially and located adjacent to each
other.
9. Control valve according to claim 8, wherein the axial stop is
embodied as a boundary of the two surrounding constructions.
10. Control valve according to claim 8, wherein the axial stop is
formed in the second bore in a direction of insertion of the
control valve.
11. Control valve according to claim 8, wherein the axial stop is
arranged and the sealing element is constructed so that the sealing
element contacts the valve receptacle at a boundary of the two
surrounding constructions.
12. Control valve according to claim 4, wherein a transition area
of the valve housing to the diameter-reduced area has an at least
partially conical construction and the sealing element is provided
on an inner casing surface thereof with a first conical area that
is adapted to the transition area of the valve housing.
13. Control valve according to claim 5, wherein the outer casing
surface of the sealing element is provided on an end contacting the
axial stop with a second conical area, so that an annular hollow
space is produced between the sealing element and the axial stop.
Description
BACKGROUND
[0001] The invention relates to a sealing element according to the
preamble of Claim 1 and to a control valve for controlling the
supply and discharge flow of a pressure medium to and from a device
for changing the control times of an internal combustion engine
according to the preamble of Claim 4.
[0002] In internal combustion engines, camshafts are used for
actuating the gas-exchange valves. Camshafts are installed in the
internal combustion engine, such that cams installed on these
camshafts contact cam followers, for example cup tappets, rocker
arms, or finger levers. If a camshaft is set in rotation, then the
cams roll on the cam followers, which in turn actuate the
gas-exchange valves. Thus, both the opening period and also the
opening amplitude, as well as the opening and closing times of the
gas-exchange valves are set through the position and the shape of
the cam.
[0003] Modern engine concepts allow variable valve train designs.
On one hand, the valve lift and valve opening period should be made
variable up to complete shutdown of individual cylinders. For this
purpose, concepts such as switchable cam followers or
electrohydraulic or electrical valve actuators are provided.
Furthermore, it has been shown to be advantageous to be able to
influence the opening and closing times of the gas-exchange valves
during the operation of the internal combustion engine. Here it is
especially desirable to influence the opening or closing times of
the intake or exhaust valves separately, in order, for example, to
selectively set a defined valve overlap. By setting the opening or
closing times of the gas-exchange valves as a function of the
current engine-map range, for example, the current rotational speed
or the current load, the specific fuel consumption can be lowered,
which has a positive effect on the exhaust-gas behavior and
increases the engine efficiency, the maximum torque, and the
maximum output.
[0004] The described variability of the gas-exchange valve control
times is achieved through a relative change of the phase position
of the camshaft relative to the crankshaft. Here, the camshaft is
usually in a driven connection with the crankshaft via a chain
drive, belt drive, gearwheel drive, or equivalent drive concepts.
Between the chain drive, belt drive, or gearwheel drive driven by
the crankshaft and the camshaft there is a device for changing the
control times of an internal combustion engine, which transmits the
torque from the crankshaft to the camshaft. Here, this device is
constructed such that during the operation of the internal
combustion engine, the phase position between the crankshaft and
camshaft is held reliably and, if desired, the camshaft can be
rotated within a certain angular range relative to the
crankshaft.
[0005] In internal combustion engines with a camshaft for each of
the intake and exhaust valves, these can each be equipped with a
camshaft adjuster. Therefore, the opening and closing times of the
intake and exhaust gas-exchange valves can be shifted in time
relative to each other and the valve overlaps are set
selectively.
[0006] The seat of modern camshaft adjusters is usually located on
the drive-side end of the camshaft. The camshaft adjuster, however,
can also be arranged on an intermediate shaft, a non-rotating
component, or the crankshaft. It is comprised of a drive wheel,
which is driven by the crankshaft at a fixed phase relationship to
the crankshaft, a driven part in drive connection with the
camshaft, and an adjustment mechanism transmitting the torque from
the drive wheel to the driven part. The drive wheel can be
constructed in the case of a camshaft adjuster not arranged on the
crankshaft as a chain, belt, or gearwheel and is driven by the
crankshaft by means of a chain drive, belt drive, or gearwheel
drive. The adjustment mechanism can be operated electrically,
hydraulically, or pneumatically.
[0007] The so-called axial-piston adjuster and rotary-piston
adjuster represent two preferred embodiments of hydraulically
adjustable camshaft adjusters.
[0008] For axial piston adjusters, the drive wheel is connected to
a piston and this is connected to the driven part via spiral
gearing. The piston separates a hollow space formed by the driven
part and the drive wheel into two pressure chambers arranged
axially relative to each other. Now if one pressure chamber is
charged with pressure medium, while the other pressure chamber is
connected to a tank, then the piston is displaced in the axial
direction. The axial displacement of the piston is converted by the
spiral gearing into a relative rotation of the drive wheel relative
to the driven part and thus of the camshaft relative to the
crankshaft.
[0009] A second embodiment of hydraulic camshaft adjusters is the
so-called rotary-piston adjuster. In these adjusters, the drive
wheel is locked in rotation with a stator. The stator and a rotor
are concentric to each other, wherein the rotor is connected with a
non-positive, positive, or form fit, for example, by means of an
interference fit, a screw or weld connection with a camshaft, an
extension of the camshaft, or an intermediate shaft. In the stator
there are several hollow spaces, which extend radially outwards
starting from the rotor, spaced apart in the peripheral direction.
The hollow spaces are pressure sealed in the axial direction by a
side cover. A vane, which is connected to the rotor and which
separates each hollow space into two pressure chambers, extends
into each of these hollow spaces. Through selective connection of
the individual pressure chambers with a pressure medium pump or
with a tank, the phase of the camshaft relative to the crankshaft
can be set or held.
[0010] For controlling the camshaft adjuster, sensors detect the
characteristic data of the engine, for example, the load state and
the rotational speed. This data is fed to an electronic control
unit, which determines a desired value of the relative phase angle
between the camshaft and crankshaft after comparing the data with a
characteristic data map of the internal combustion engine. By means
of sensors, for example Hall sensors, the actual value of the phase
angle and a deviation of the actual value from the desired value
are determined. Then the control command is led to a control unit
of the control valve, which controls the supply and discharge flow
of pressure medium to and from the various pressure chambers and
thus controls the adjustment of the phase position of the
camshaft.
[0011] To adjust the phase position of the camshaft relative to the
crankshaft, in hydraulic camshaft adjusters, one of the two
pressure chambers acting against each other in a hollow space is
connected to a pressure medium pump and the other is connected to
the tank. The supply of pressure medium to one chamber in
connection with the discharge of pressure medium from the other
chamber displaces the piston separating the pressure chambers in
the axial direction, whereby the camshaft is rotated relative to
the crankshaft in axial piston adjusters via the spiral gearing. In
rotary piston adjusters, the pressure loading of one chamber and
the pressure relieving of the other chamber displaces the vane and
thus directly rotates the camshaft relative to the crankshaft. To
keep the phase position, both pressure chambers are either
connected to the pressure medium pump or separated both from the
pressure medium pump and also from the tank.
[0012] The control of the pressure medium flows to and from the
pressure chambers is realized by means of a control valve, usually
a 4/3 proportional valve. A valve housing is provided with a
connection for each pressure chamber (work connection), a
connection to the pressure medium pump, and at least one connection
to a tank. Within the essentially hollow cylindrical valve housing
there is an axially displaceable control piston. The control piston
can be brought axially into any position between two defined end
positions against the spring force of a spring element by means of
an adjustment unit, for example, an electromagnetic or hydraulic
adjustment unit. The control piston is further provided with ring
grooves and control edges, whereby the individual pressure chambers
can be connected selectively to the pressure medium pump or to the
tank. Likewise a position of the control piston can be provided, in
which the pressure medium chambers are separated both from the
pressure medium pump and also from the pressure medium tank.
[0013] Such control valves can be constructed as a central valve or
as an insert valve. In the case of a central valve, this is
arranged within the camshaft or an extension of the camshaft in the
area of the camshaft adjuster. In the case of an insert valve, a
surrounding construction of the internal combustion engine is
provided with a valve receptacle, in which the control valve is
inserted. In the casing surface of the valve receptacle, usually
constructed as a bore, there are pressure medium lines, which
communicate with the pressure medium connections of the control
valve. Such a surrounding construction can be, for example, a
cylinder head or a cylinder head cover.
[0014] In DE 102 23 431 B4, such a device with a control valve in
an insert construction is shown. The device is comprised of a
camshaft-fixed driven unit, a drive unit driven by the crankshaft,
and two side covers. The drive unit is arranged coaxial to the
driven unit and is provided with several recesses spaced apart in
the peripheral direction. The recesses are pressure sealed by the
drive unit, the driven unit, and the side covers and thus form
pressure spaces. A vane extends into each pressure space, wherein
each vane is arranged in a vane groove formed on the driven unit.
Each vane divides a pressure space into two pressure chambers
acting against each other. The pressure chambers communicate via
pressure medium lines formed in a camshaft by means of rotary
feedthroughs with other pressure medium lines formed in a cylinder
head or a cylinder head cover.
[0015] The other pressure medium lines can be connected by means of
a control valve, in this case a 4/3 directional control valve,
selectively to a pressure medium reservoir or to a pressure medium
pump. The control valve is composed of an adjustment unit and a
valve body. The valve body is surrounded by an adapter sleeve,
wherein this sleeve is arranged in a bore of a cylinder head cover.
In the adapter sleeve, three radial openings spaced apart axially
and in the peripheral direction relative to each other are formed,
which are used as pressure medium connections. A fourth pressure
medium connection is formed in the axial direction on the end of
the valve body facing away from the adjustment unit. Each radial
opening is connected to a pressure medium line via a rising
channel. Pressure medium is led via a pressure medium line to the
middle radial opening in the axial direction and from there into
the interior of the sleeve, wherein the pressure medium flow is
guided dependent on the control position of the control valve to
one of the two other radial openings. From there the pressure
medium is led via another rising line to a pressure medium line,
which communicates with one of the rotary feedthroughs and also
with a firsts group of pressure chambers.
[0016] In an analogous way, pressure medium is led from a second
group of pressure chambers via the rotary feedthrough and pressure
medium lines to another rising line, which opens into the third
opening. From there the pressure medium is led via the control
valve to the axial discharge connection. The rising lines are
constructed as grooves constructed in the bore in the cylinder head
cover and open to the adapter sleeve. Furthermore, the rising lines
are sealed against each other, so that the outer diameter of the
adapter sleeve is adapted to the inner diameter of the bore. The
pressure medium lines communicating with the rising lines are in
this embodiment constructed as grooves formed in the cylinder head
cover and open to the cylinder head. To allow discharge of the
pressure medium forced from the pressure chambers, the cylinder
head is provided with a discharge bore coaxial to the bore formed
in the cylinder head cover.
[0017] To prevent leakage between the rising lines and the
discharge bore, the inner diameter of the bore and the discharge
bore are identical and the adapter sleeve extends at least
partially into the adapter bore. The adapter sleeve now forms a
sealed contact on the casing surface of the discharge bore, whereby
discharge of the pressure medium from the rising lines via the
discharge bore into the interior of the cylinder head is prevented.
Slight offset of the bores causes damage to the adapter sleeve
during assembly, which can lead to loss of the sealing effect
between the components.
[0018] To guarantee the sealing function between the rising
channels and the discharge bore, an exact coaxial alignment of the
bore to the discharge bore and an exact adaptation of the adapter
sleeve diameter to the inner diameter of the discharge bore is
necessary. This is possible only with very high expense due to the
tolerances inevitably appearing in the production process of the
individual components.
SUMMARY
[0019] The invention is based on the objective of avoiding these
mentioned disadvantages and providing a sealing arrangement for a
control valve, which is not susceptible to tolerances appearing in
the system. Furthermore, a sealing element is provided, which is
used in this sealing arrangement.
[0020] A control valve for controlling the supply and discharge
flow of pressure medium to and from a device for changing the
control times of an internal combustion engine comprises, among
other things, an essentially cylindrical valve housing, on which
pressure medium connections are formed, and an axially displaceable
control piston arranged within the valve housing. Here, a
connection between the different pressure medium connections can be
established or separated as a function of the position of the
control piston. The valve housing is arranged within a valve
receptacle, wherein the insert depth of the valve housing into the
valve receptacle is limited by an axial stop constructed in the
valve receptacle.
[0021] The objective is met according to the invention in that the
axial stop is constructed as a circular or circular ring-shaped
wall, which extends radially inwards starting from an inner casing
surface of the valve receptacle and that between the valve housing
and the axial stop of the valve receptacle there is a sealing
element.
[0022] Such a control valve comprises a cylindrical valve housing
and a control piston arranged axially displaceable in the valve
housing. The valve housing is provided with radial openings, which
are used as pressure medium connections. By means of an adjustment
unit, the control piston within the valve housing can be brought
into any position between two end stops. In this way, the control
piston connects or separates various pressure medium connections
based on the relative position to the valve housing. The control
piston can be in direct contact with the valve housing. Another
possibility consists in providing, as shown in DE 102 23 431, a
hollow control sleeve between the valve housing and the control
piston. The inner diameter of the control sleeve is adapted to the
outer diameter of the control piston and the outer diameter of the
control sleeve is adapted to the inner diameter of the valve
housing. Furthermore, the outer casing surface of the control
sleeve is provided with several ring grooves, which communicate on
one side with the pressure medium connections and on the other side
via radial openings with the interior of the control sleeve.
Through axial shifting of the control piston, connections between
the ring grooves, and thus the pressure medium connections, and
optionally with an axial pressure medium connection, can be
established or separated.
[0023] Such control valves are arranged in valve receptacles, in
which pressure medium channels are formed, which communicate with
the pressure medium connections. The pressure chambers of the
camshaft adjuster are connected selectively via the pressure medium
channels with a pressure medium pump or a pressure medium
reservoir. Such valve receptacles can be formed, for example, in a
cylinder head or a cylinder head cover. In this case, one talks of
an insert valve. Another possibility is to use the control valve as
a central valve. In this case, it is arranged in a valve receptacle
in the camshaft and rotates with the camshaft during the operation
of the internal combustion engine.
[0024] In both cases, the valve receptacle is constructed as a
cylindrical bore. The outer diameter of the valve housing is
adapted to the inner diameter of the bore, whereby the pressure
medium connections are sealed against each other. Within the bore
there is an axial stop for the valve housing. The axial stop can be
constructed as a wall limiting the bore. A diameter narrowing of
the bore is also conceivable. In this case, the bore is constructed
with a stepped cross section, whereby a ring section is
constructed, which is used as an axial stop for the valve housing.
Furthermore, between the axial stop and the valve housing there is
a sealing ring, which prevents leakage currents in the axial
direction.
[0025] The radial ring sealing point described in DE 102 23 431 is
displaced in the axial direction by this projection, whereby the
effects by tolerances in the dimensions of the control valve are
not critical.
[0026] In an advantageous improvement of the invention, it is
provided that the axial stop-side end of the valve housing is
constructed with an area reduced in outer diameter, wherein the
sealing element is arranged at least partially in the area reduced
in outer diameter. The sealing element is further constructed as a
sealing ring with an outer and an inner casing surface.
[0027] The area reduced in outer diameter simplifies the mounting
of the sealing element and the control valve in the valve
receptacle. The inner diameter of the sealing element constructed
as a sealing element is adapted to the outer diameter of the area
reduced in outer diameter. The sealing ring is placed in this area
on the control valve and is positioned with it together in the
valve receptacle. Thus, due to the guidance and centering
experienced by the sealing element by means of the control valve,
incorrect mounting is prevented and the sealing effect is more
process reliable.
[0028] It can be further provided that the sealing element is
composed of an elastomer. In the case of a valve housing with an
area reduced in outer diameter on the axial stop-side end, the
sealing ring contacts the outer casing surface of this area.
Furthermore, it is clamped in the axial direction by the valve
housing and the axial stop. During the mounting, the sealing ring
is pressed by the valve housing against the axial stop. In this
way, it deforms elastically, wherein deformation radially inwards
is prevented by the valve housing. The elastic deformation thus
obtains a "preferred direction," namely radially outwards, against
the inner casing surface of the valve receptacle. Therefore, the
sealing effect is increased or reached significantly earlier.
Another advantage in the use of an elastic sealing ring is to be
seen in that axial tolerances can be compensated through its
deformability.
[0029] The elastomer can be, for example, a fluoro-rubber or an
acrylonitrile butadiene rubber. These materials are very well
suited due to their high resistance relative to environmental
influences in internal combustion engines, such as high
temperatures and contact with motor oil.
[0030] In another realization of the invention, the valve
receptacle is assembled from a first and a second bore, wherein the
bores are embodied in different surrounding constructions, at least
approximately coaxial and adjacent to each other. One example for
such an embodiment is the valve receptacle shown in DE 102 23 431.
A bore is constructed in a cylinder head and a cylinder head cover.
The two bores are arranged such that they are at least
approximately coaxial to each other when the cylinder head cover is
mounted on the cylinder head.
[0031] In one improvement of the invention, the axial stop can be
formed at the boundary of the two surrounding constructions.
[0032] In this embodiment, the inner diameter of the second bore is
smaller than that of the first bore. At the boundary between the
two bores there is a step. The advantage of this variant lies in
the low production costs, because the step is realized by lining up
two bores of different inner diameters.
[0033] Alternatively, the axial stop is formed in the second bore
in the insertion direction of the control valve. The advantage is
provided in that the step-like profile can be constructed such that
the sealing element at the boundary of the two surrounding
constructions can contact the inner casing surfaces of the
bores.
[0034] In this embodiment according to the invention, because the
outer casing surface of the valve housing no longer provides the
sealing function at the boundary of the surrounding constructions,
the inner diameter of the second bore at the boundary between the
surrounding constructions can be greater than the inner diameter of
the first bore and thus than the outer diameter of the valve
housing. Thus, even for a slight offset of the bores relative to
each other, non-destructive assembly of the control valve in the
valve receptacle is guaranteed.
[0035] It is further provided that the axial stop is arranged and
the sealing element is constructed so that the sealing element at
the boundary of the two surrounding constructions contacts the
valve receptacle. Any possible leakage paths created by edges
deviating from the rectangular shape are reliably blocked by the
elastic deformation of the sealing element.
[0036] In another advantageous improvement of the invention, the
transition area of the valve housing to the diameter-reduced area
is at least partially conical. Furthermore, the sealing element at
its inner casing surface is provided with a first conical area,
wherein this is adapted to the transition area of the valve
housing.
[0037] The valve housing is comprised of a first and a second
cylindrical area. The first cylindrical area forms a sealed contact
on the inner wall of the first bore. The second area involves the
area reduced in outer diameter. A conical transition area is formed
at the transition from the first to second area. Here the entire
diameter reduction can be bridged by means of the conical area. It
is also conceivable that starting from the first area, the valve
housing extends radially inwards before it transitions into the
conical area, which flows into the area reduced in outer diameter.
The sealing ring is arranged in this transition area, wherein its
contours contacting the valve housing are adapted to the contours
of the valve housing, especially the conical area. During the
mounting of the control valve in the valve receptacle, the valve
housing exerts a force on the sealing ring. Due to the pressure
surface that is not parallel to the axial stop, a force is applied
to the sealing ring both in the axial and also radial directions.
Consequently, a better sealing effect is achieved in the radial
direction.
[0038] In an advantageous improvement of the invention, the outer
casing surface of the sealing element is provided with a second
conical area at the end contacting the axial stop, so that an
annular hollow space is produced between the sealing element and
the axial stop. If larger axial tolerances have to be compensated,
for example, and thus the valve must be positioned farther within
the valve receptacle, then the sealing ring can bulge into the
hollow space while maintaining its sealing function. Larger
production tolerances can be compensated and thus costs can be
saved.
[0039] Further proposed is a sealing element in the form of a
sealing ring for sealing an axial end of a control valve of a
device for changing the control times of gas-exchange valves with
an inner casing surface and an outer casing surface. According to
the invention, the objective is met in that the inner and the outer
casing surfaces are provided with a conical area at each of its
ring edges. In this way the two conical areas are formed at ring
edges of the sealing ring offset relative to each other in the
axial direction. One of the conical areas is provided for
contacting a conical area of a component, which is to seal the
sealing ring against a second component. This is meant especially
for a sealing assembly of a component within a bore, wherein the
sealing ring is charged with an axially directed force. The conical
contact surface of the component converts the axially directed
force into radial and axial force components, whereby the sealing
ring deforms in the radial direction and thus increases the sealing
effect. Through the conical construction of another ring edge, a
ring-shaped hollow space is maintained, in which the sealing ring
can bulge under the effect of forces. Due to this hollow space,
large axial tolerances can be compensated without negatively
affecting the sealing effect.
BRIEF DESCRIPTION OF THE DRAWINGS
[0040] Additional features of the invention emerge from the
following description and from the drawings, in which embodiments
of the invention are shown simplified. Shown are:
[0041] FIG. 1 a longitudinal cross-sectional view through a device
for changing the control times of an internal combustion engine
with pressure medium circuit,
[0042] FIG. 2 a cross sectional view through the device shown in
FIG. 1 along the line II-II,
[0043] FIG. 3 a longitudinal cross-sectional view through a control
valve mounted in a valve receptacle according to a first sealing
concept according to the invention,
[0044] FIG. 4 a cross-sectional view along the line IV-IV from FIG.
3,
[0045] FIG. 5 a longitudinal cross-sectional view through a control
valve mounted in a valve receptacle according to a second sealing
concept according to the invention,
[0046] FIG. 6 a cross-sectional view along the line VI-VI from FIG.
5,
[0047] FIG. 7 a longitudinal cross-sectional view through a sealing
ring according to the invention, and
[0048] FIG. 8 a cross-sectional view along line VIII-VIII of FIG.
7.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0049] FIGS. 1 and 2 show a device 1 for changing the control times
of an internal combustion engine. The device 1 essentially
comprises a stator 2, and a rotor 3 arranged concentrically to this
stator. A drive wheel 4 is locked in rotation with the stator 2 and
constructed as a chain wheel in the illustrated embodiment.
Embodiments of the drive wheel 4 as a belt or gearwheel are also
conceivable. The stator 2 is supported rotatably on the rotor 3,
wherein five recesses 5 spaced apart in the peripheral direction
are provided in the illustrated embodiment on the inner casing
surface of the stator 2. The recesses 5 are limited in the radial
direction by the stator 2 and the rotor 3, in the peripheral
direction of two side walls 6 of the stator 2, and in the axial
direction by a first and a second side cover 7, 8. Each of the
recesses 5 is pressure sealed in this way. The first and the second
side covers 7, 8 are connected to the stator 2 by means of
connection elements 9, for example, screws.
[0050] On the outer casing surface of the rotor 3 there are axial
vane grooves 10, wherein a radially extending vane 11 is arranged
in each vane groove 10. A vane 11 extends into each recess 5
starting from the appropriate vane groove 10, wherein the vanes 11
contact in the radial direction the stator 2 and in the axial
direction the side covers 7, 8. Each vane 11 divides a recess 5
into two pressure chambers 12, 13 working against each other. To
guarantee a pressure-sealed contact of the vane 11 on the stator 2,
between the groove bases 14 of the vane grooves 10 and the vanes 11
there are leaf spring elements 15, which apply a force on the vanes
11 in the radial direction.
[0051] By means of first and second pressure medium lines 16, 17,
the first and second pressure chambers 12, 13 are connected via a
control valve 18 to a pressure medium pump 19 or a tank 20. In this
way, an adjustment drive is formed, which allows a relative
rotation of the stator 2 relative to the rotor 3. Here, either all
of the first pressure chambers 12 are connected to the pressure
medium pump 19 and all of the second pressure chambers 13 are
connected to the tank 20, or there is the exact opposite
configuration. If the first pressure chambers 12 are connected to
the pressure medium pump 19 and the second pressure chambers 13 are
connected to the tank 20, then the first pressure chambers 12
expand at the cost of the second pressure chambers 13. This
produces a shift of the vanes 11 in the peripheral direction, in
the direction shown by the arrow 21. By shifting the vanes 11, the
rotor 3 is rotated relative to the stator 2.
[0052] The stator 2 is driven by the crankshaft in the shown
embodiment by a not-shown chain drive attaching to its drive wheel
4. The drive of the stator 2, by a belt or gearwheel drive, is also
conceivable. The rotor 3 is connected by a non-positive, positive,
or form fit, for example, by means of an interference fit or by a
screw connection by means of a central screw, to a not-shown
camshaft. From the relative rotation of the rotor 3 relative to the
stator 2, due to the supply or discharge of pressure medium towards
or from the pressure chambers 12, 13, a phase shift results between
the camshaft and crankshaft. Through targeted feeding and discharge
of pressure medium into and out of the pressure chambers 12, 13,
the control times of the gas-exchange valves of the internal
combustion engine can be varied selectively.
[0053] The pressure medium lines 16, 17 are constructed in the
shown embodiment as channels within the rotor 3, which extend from
a central bore 22 of the rotor 3 to its outer casing surface.
Within the central bore 22 there can be a not-shown central valve,
by means of which the pressure chambers 12, 13 can be connected
selectively to the pressure medium pump 19 or to the tank 20.
Another possibility is provided in arranging a pressure medium
distributor within the central bore 22, which connects the pressure
medium lines 16, 17 via pressure medium channels and ring grooves
to pressure medium connections A, B, P, T of a control valve 18
attached on the outside.
[0054] The essentially radial side walls 6 of the recesses 5 are
provided with formations 23, which extend in the peripheral
direction into the recesses 5. The formations 23 are used as stops
for the vanes 11 and guarantee that the pressure chambers 12, 13
can be supplied with pressure medium even when the rotor 3 assumes
one of its two extreme positions relative to the stator 2, in which
the vanes 11 contact one of the side walls 6.
[0055] For inadequate supply of pressure medium to the device 1,
for example, during the startup phase of the internal combustion
engine, the rotor 3 moves uncontrollably relative to the stator 2
due to the alternating and dragging moments that the camshaft
exerts on the rotor. In a first phase, the reactive torque of the
camshaft forces the rotor 3 relative to the stator 2 in a
peripheral direction that lies opposite the rotational direction of
the stator 2 until these contact the side walls 6. Then the
alternating moments exerted by the camshaft on the rotor 3 lead to
back and forth oscillations of the rotor 3 and thus of the vanes 11
in the recesses 5 until at least one of the pressure chambers 12,
13 is filled completely with pressure means. This leads to higher
wear and to the development of noise in the device 1. To prevent
these results, a locking element 24 is provided in the device 1.
For this purpose, a pot-shaped piston 26 is arranged in an axial
bore 25 of the rotor 3. A first spring 27 applies a force to this
piston in the axial direction. The first spring 27 is supported in
the axial direction on one side on a ventilation element 28 and is
arranged with its axial end facing away from this ventilation
element within the pot-shaped piston 26. In the first side cover 7
there is a connecting rod 29, such that the piston 26 can engage
this connecting rod in at least one relative position of the rotor
to the stator. In this position, the piston 26 is forced into the
connecting rod 29 by the first spring 27 if there is inadequate
supply of pressure medium to the device 1. In this state, the rotor
3 is locked in this position relative to the stator 2. The locking
position primarily corresponds to the position that is to be
assumed during the startup of the internal combustion engine.
Furthermore, means are provided to pull the piston 26 back into the
axial bore 25 for an adequate supply of pressure medium to the
device 1 and thus to cancel the locking. This is typically
implemented with pressure medium, which is led via not-shown
pressure medium lines into a recess 30, which is formed on the
cover-side end of the piston 26. To be able to discharge leakage
oil from the spring space of the axial bore 25, the ventilation
element 28 is provided with axial grooves, along which the pressure
medium can be led to a bore in the second side cover 8.
[0056] In FIG. 1, the pressure medium circuit 31 is also shown.
From a tank 20, a supply connection P of a control valve 18 is
supplied with pressure medium by means of a pressure medium pump
19. Simultaneously, pressure medium is led by the control valve 18
into the tank 20 via a discharge connection T. The control valve 18
further has two work connections A, B, with the first work
connection A communicating with the first pressure chambers 12 and
the second work connection B communicating with the second pressure
chambers 13. By means of an electromagnetic adjustment device 32,
which acts against the spring force of a second spring 33, the
control valve 18 can be brought into three positions. In a first
position of the control valve 18, which corresponds to a
non-powered state of the adjustment device 32, the first work
connection A and thus the first pressure chambers 12 are connected
to the discharge connection T. Simultaneously, the supply
connection P communicates with the second work connection B and
thus with the second pressure chambers 13. Thus, while pressure
medium is discharged from the first pressure chambers 12, pressure
medium are led to the second pressure chambers 13, whereby the
vanes 11 are shifted in the peripheral direction. This produces a
change of the phase position between the rotor 3 and the stator 2
and thus between the camshaft and crankshaft.
[0057] In a middle position, both the first work connection A and
also the second work connection B are separated both from the
supply connection P and also from the discharge connection T.
Pressure medium can flow neither to nor from the pressure chambers
12, 13 and the phase position of the camshaft is held relative to
the crankshaft. An alternative possibility is provided by
connecting both work connections A, B to the supply connection P,
in order to compensate for leakage appearing in the device 1.
[0058] In a third position of the control valve 18, the supply
connection P is connected to the first work connection A and thus
to the first pressure chamber 12, while the second pressure chamber
13 is connected to the second work connection B to the discharge
connection T. Analogous to the first control position of the
control valve 18, the phase position of the camshaft relative to
the crankshaft is changed only in the opposite direction.
[0059] FIG. 3 shows a control valve 101 according to the invention,
which has an adjustment device 102, an essentially hollow
cylindrical control housing 103, a similarly essentially hollow
cylindrical control piston 104, and a similarly essentially hollow
cylindrical valve housing 105. The control housing 103 is arranged
stationary within the valve housing 105. Here, the inner diameter
of the valve housing 105 is adapted to the outer diameter of the
control housing 103. Furthermore the control piston 104 is
displaceable axially within the control housing 103, wherein the
outer diameter of the control piston 104 is adapted to the inner
diameter of the control housing 103.
[0060] The valve housing 105 is arranged within a valve receptacle
106. The valve receptacle 106 is assembled from two bores 107, 108,
which are formed in two surrounding constructions 109, 110. The
first surrounding construction 109 is fixed on the second
surrounding construction 110 and the bores 107, 108 are constructed
and arranged such that these are at least approximately coaxial to
each other. The inner diameter of the second bore 108 is smaller in
this embodiment than the inner diameter of the first bore 107.
Therefore, at the boundary between the first surrounding
construction 109 and the second surrounding construction 110 there
is a circular ring-shaped axial stop 111, which limits the
insertion depth of the control valve 101.
[0061] The valve housing 105 is provided on its axial stop-side end
with an area 112 reduced in outer diameter, wherein the outer
diameter of the area 112 reduced in outer diameter is smaller than
the inner diameter of the second bore 108. Furthermore, in this
embodiment the transition to the area 112 reduced in outer diameter
has a stepped construction. The valve housing 105 passes through
the first bore 107 and extends with its diameter-reduced area 112
at least partially into the second bore 108. Here, the outer
diameter of the valve housing 105 is adapted to the inner diameter
of the valve receptacle 106.
[0062] Three pressure medium channels 113 are formed at the
boundary between the first and second surrounding constructions
109, 110. The pressure medium channels 113 are constructed in the
form of grooves, which are formed either in the surface of the
first or second surrounding constructions 109, 110. Each of the
pressure medium channels 113 opens into a rising groove 114a, 114b,
114p, which are formed in the casing surface of the first bore 107.
The rising grooves 114a, 114b, 114p are offset relative to each
other in the peripheral direction of the first bore 107 and extend
essentially in the axial direction of the valve housing 105. Each
of the rising grooves 114a, 114b, 114p communicates via
corresponding radial openings 115a, 115b, 115p, which are formed in
the valve housing 105 and which are used as work connections A, B,
and supply connection P, with the interior of the valve housing
105.
[0063] The outer casing surface of the control housing 103 is
provided with three ring grooves 116a, 116b, 116p offset relative
to each other axially. Here, the rising grooves 114a, 114b, 114p,
the radial openings 115a, 115b, 115p, and the ring grooves 116a,
116b, 116p are arranged so that the first rising groove 114a
communicates by means of the first radial opening 115a exclusively
with the first ring groove 116a, the second rising groove 114b
communicates by means of the second radial opening 115b exclusively
with the second ring groove 116b, and the third rising groove 114p
communicates by means of the third radial opening 116p exclusively
with the third ring groove 116p. Each of the ring grooves 116a,
116b, 116p further communicates by means of openings 117a, 117b,
117p formed in their groove bases with the interior of the control
housing 103.
[0064] The control piston 104 arranged in the interior of the
control housing 103 can be displaced within the control housing 103
axially by means of an adjustment device 102 via a push rod 119
against the force of a first spring element 120. The control piston
104 is provided with two control sections 121, wherein the outer
periphery of the control sections 121 is adapted to the inner
periphery of the control housing 103. The control sections 121 can
be made as separate components and mounted on the control piston
104 or constructed in one piece with this piston as shown in FIG.
3. Outside of the control sections 121 the outer diameter of the
control piston 104 has a smaller construction. The control sections
121 are constructed and arranged on the control piston 104 such
that a fourth ring groove 122 is formed, which connects the first
or second ring groove 116a, 116b to the third ring groove 116p
after the adjustment of the control piston 104 relative to the
control housing 103.
[0065] The control piston 104 further has an open construction on
its end attaching to the first spring element 120. Therefore, a
connection between the interior of the control piston 104 and the
second bore 108 is produced and thus describes a discharge
connection T. Fourth openings 123 are formed on the push rod-side
end of the control piston 104, whereby the interior of the control
piston 104 is connected hydraulically with the outside of the
control piston 104. The fourth openings 123 are located in the
shown embodiment outside of the fourth ring groove 122 in the outer
casing surface of the control piston 104.
[0066] By means of the adjustment device 102, the control piston
104 can be moved via the push rod 119 within the control housing
103 into any position between two maximum values. Here, the first
spring element 120 exerts a restoring force on the control piston
104. As a control device 102, for example, hydraulic adjustment
devices or, like in the illustrated embodiment, electromagnetic
adjustment devices can be used. The electromagnetic adjustment
device 102 is comprised of a coil that is arranged in a magnetic
field of one or more permanent magnets. A power-supply unit is
allocated to the coil, by means of which this coil can be excited
with an electric current. Here, several possibilities for exciting
the coil are conceivable. One possibility would be, for example, to
vary the position of the coil within the magnetic field through
variable current intensities, wherein high current intensities
would correspond to a large deflection and low current intensities
would correspond to a small deflection. Also conceivable is to
excite the coil by means of pulsed currents. For example, a
rectangular voltage between the values 0V and a constant voltage
V.sub.0 can be applied to the electrical poles of the coil. The
deflection of the coils and thus the control piston 104 is now
defined by the ratio of the time intervals, in which the voltage
V.sub.0 or no potential difference is applied to the electrical
poles. The greater the voltage-less intervals are, the smaller the
deflection of the coil. The longer the time intervals are in which
the voltage V.sub.0 is applied, the greater the deflection.
[0067] In the shown embodiment in FIG. 3 and FIG. 4, a 4/3
direction control valve with four pressure medium connections A, B,
P, T is shown, wherein the control piston 104 can be located
essentially in three control states. However, the invention is not
limited to such a four/three direction control valve, but instead
embodiments, in which a 4/4 directional control valve or other
valves are used, are by all means also conceivable.
[0068] Below, the function of the 4/3 directional control valve
shall be described as an example. By means of one of the pressure
medium channels 113, the third rising groove 114p is charged with
pressure medium. In each control position of the control valve 101,
the pressure medium is led via the third radial opening 115p, the
third ring groove 116p, and the third openings 117p into the fourth
ring groove 122.
[0069] In a first state of the control valve 101, which corresponds
to a non-powered state of the adjustment device 102, the control
piston 104 is shifted by means of the spring force of the first
spring element 120 into a maximum deflected position in the
direction of the adjustment device 102. In this control position,
the fourth ring groove 122 communicates via the first openings
117a, the first ring groove 116a, and the first radial opening 115a
with the first rising groove 114a, from where the pressure medium
is led to the first pressure chambers 12.
[0070] In a second control position of the control valve 101, in
which the adjustment device 102 receives maximum power, the control
piston 104 is deflected to a maximum extent in the direction of the
first spring element 120. In this case, the fourth ring groove 122
communicates both with the third openings 117p and also with the
second openings 117b. Pressure medium is now led via the second
ring groove 116b, the second radial opening 115b, and the second
rising groove 114b to the corresponding pressure medium channel 113
and from there to the second pressure chambers 13.
[0071] In a third state, the control piston 104 is located in a
middle position, in which the fourth ring groove 122 communicates
only with the third openings 117p. In this case, the pressure
medium supply to both pressure chambers 12, 13 is blocked.
Alternatively, it is likewise conceivable that, in this middle
position, the fourth ring groove 122 communicates with the first,
the second, and the third openings 117a, 117b, 117p. In this case
pressure medium is led to both pressure chambers 12, 13, whereby
leakage is compensated and the phase position is held functionally
locked between the camshaft and crankshaft.
[0072] In the first and second control position, the control
sections 121 completely open or close the appropriate openings
117a, 117b. Naturally the control piston 104 can also be positioned
at any position between these two extreme values, whereby the
openings 117a, 117b are only partially opened or covered.
Therefore, the flow resistance and thus the extent of pressure
medium supply to the pressure chambers 12, 13 can be set.
[0073] To prevent pressure medium from being able to flow from the
rising grooves 114a, 114b, 114p directly into the second bore 108
and to prevent leakage flows between the rising grooves 114a, 114b,
114p, especially at the boundary between the surrounding
constructions 109, 110, a sealing element 124 is provided between
the valve housing 105 and the axial stop 111. The sealing element
124 is constructed in the shown embodiment as an elastically
deformable sealing ring and preferably from fluoro rubber or
acrylonitrile butadiene rubber. Advantageously, the sealing element
124 is arranged on the area 112 of the valve receptacle 105 reduced
in outer diameter. During the mounting of the control valve 101 in
the valve receptacle 106, the sealing element 124 is positioned in
the area 112 of the valve housing 105 reduced in outer diameter.
Then the valve housing 105 is inserted and fixed in the valve
receptacle 106. Through the arrangement on the area 112 reduced in
outer diameter, the sealing element 124 is centered and guided
during the mounting process, whereby incorrect mounting can be
reliably prevented. Through the use of an elastically deformable
sealing element 124, axial tolerances can be compensated.
[0074] The sealing element 124 is pressed 111 by the valve housing
105 in the installed state against the axial stop 111. Here, it is
surrounded by a U shape by the axial stop 111 and the step of the
area 112 of the valve housing 105 reduced in outer diameter. Due to
the forces, the sealing element 124 deforms elastically and is thus
pressed against the inner casing surface of the valve receptacle
106 due to the U-shaped clamping device. In this way, an optimal
and early sealing effect is guaranteed in the axial direction.
[0075] Advantageously, the sealing element 124 is arranged such
that it contacts the inner casing surface of the valve receptacle
106 at the boundary between the two surrounding constructions 109,
110. Therefore, any possible gaps at this boundary are closed and
the sealing effect is guaranteed in the peripheral direction.
[0076] Through the construction of the second bore 108 with a small
inner diameter in comparison with the first bore 107, an axial stop
111 is formed, which limits the insertion depth of the control
valve 101 in the valve receptacle 106 and acts as a sealing surface
in interaction with the sealing element 124. The control valve 101
engages only with its area 112 reduced in outer diameter into the
second bore 108. Because this area 112 does not take on a sealing
function in interaction with the inner casing surface of the second
bore 108, its outer diameter can be smaller than the inner diameter
of the second bore 108, which makes the system not susceptible to
tolerances.
[0077] Furthermore, additional seals 125 are provided at the
boundary between the control housing 103 and the valve housing 105
or the valve housing 105 and the first bore 107, which prevent
leakage flows in the direction of the adjustment device 102 and
thus into the engine space.
[0078] FIGS. 5 and 6 show a second embodiment of the invention. The
second embodiment is identical to the first embodiment for the most
part, which is shown in FIGS. 3 and 4. In contrast to the first
embodiment, the second bore 108 has a stepped construction. Here,
the inner diameter of a first area 126, which connects directly to
the first bore 107, is larger than the inner diameter of the first
bore 107. Furthermore, the inner diameter of a second area 127
adjacent to the first area 126 is smaller than the inner diameter
of the first bore 107. At the transition from the first area 126 to
the second area 127, an axial stop 111 is formed. The valve housing
105 passes through the first bore 107 of the first surrounding
construction 109 and engages in the second surrounding construction
110. Due to the larger inner diameter of the first area 126 of the
second bore 108, this is possible even for a slight offset of the
bores 107, 108 relative to each other. The transition area 128 of
the valve housing 105 to the diameter-reduced area 112 in not
stepped in this embodiment as in the first embodiment, but instead
at least partially conical. The sealing element 124 is constructed
as a sealing ring and arranged in the transition area 128, wherein
the form of the sealing element 124 is adapted to the shape of the
transition area 128, especially its conicity 127. The inner casing
surface 133 of the sealing element 124 thus has a first conical
area 129, wherein the inner diameter continuously decreases
starting from the end in the axial direction until it corresponds
to the outer diameter of the area 112 reduced in outer
diameter.
[0079] On an outer casing surface 134 of the sealing element 124, a
second conical area 131 is formed, wherein this is formed on the
ring edge 130 offset in the axial direction relative to the first
conical area 129. The outer diameter of the sealing element 124
increases in the axial direction starting from the end until the
maximum outer diameter of the sealing element 124 is reached.
[0080] The axial length of the first area 126, the area 112 reduced
in outer diameter, and the sealing element 124 is constructed so
that the sealing element 124 contacts both the first bore 107 and
also the second bore 108 in the area of the boundary between the
first surrounding construction 109 and the second surrounding
construction 110.
[0081] The conical area formed in the outer casing surface of the
valve housing 105 has the effect that the sealing element 124 forms
a pressure sealed contact on the casing surface of the first bore
107 and the casing surface of the first area 126 of the second bore
108. Due to the shape of the sealing element 124, between the
second bore 108 and the sealing element 124 there is a hollow space
132. This allows the compensation of any axial play during the
mounting. In this case, the valve housing 105 can force material of
the sealing element 124 into the hollow space 132, whereby the
control valve 101 can be inserted in the axial direction farther
into the valve receptacle 106. This hollow space 132 allows axial
tolerances to be compensated to a greater extent than is allowed in
the sealing element 124 shown in the first embodiment.
[0082] Obviously, the sealing element 124 of the second embodiment
can also be inserted into the valve receptacle 106 of the first
embodiment and vice versa. Furthermore, both sealing elements 124
and the control valve 101 can be used in a single stepped bore,
which is used as the valve receptacle 106. Likewise, the sealing
element 124 and the control valve 101 are inserted into a bore,
which is limited by a circular ring-shaped wall extending in the
radial direction.
[0083] FIGS. 7 and 8 show a sealing element 124 according to the
invention in the shape of a sealing ring. A ring edge 130 of the
inner 133 and the outer casing surface 134 of the sealing element
124 has a conical construction. The conicity is constructed such
that the partial cross sectional shape of the sealing element 124
is reached through material removal of two edges of a rectangular
surface. That is, the first conical area 129 on the inner casing
surface 133 is funnel shaped and the second conical area 131 on the
outer casing surface 134 is frustum shaped.
[0084] Furthermore, the sealing element 124 is composed of an
elastomer. Here, a fluoro rubber or an acrylonitrile butadiene
rubber can be used as the material, for example.
REFERENCE SYMBOLS
[0085] 1 Device [0086] 2 Stator [0087] 3 Rotor [0088] 4 Drive wheel
[0089] 5 Recesses [0090] 6 Side wall [0091] 7 First side cover
[0092] 8 Second side cover [0093] 9 Connection element [0094] 10
Vane groove [0095] 11 Vane [0096] 12 First pressure chamber [0097]
13 Second pressure chamber [0098] 14 Groove base [0099] 15 Leaf
spring element [0100] 16 First pressure medium line [0101] 17
Second pressure medium line [0102] 18 Control valve [0103] 19
Pressure medium pump [0104] 20 Tank [0105] 21 Arrow [0106] 22
Central bore [0107] 23 Formations [0108] 24 Locking element [0109]
25 Axial bore [0110] 26 Piston [0111] 27 First spring [0112] 28
Ventilation element [0113] 29 Connecting rod [0114] 30 Recess
[0115] 31 Pressure medium circuit [0116] 32 Adjustment device
[0117] 33 Second spring [0118] A First work connection [0119] B
Second work connection [0120] P Supply connection [0121] T
Discharge connection [0122] 101 Control valve [0123] 102 Adjustment
device [0124] 103 Control housing [0125] 104 Control piston [0126]
105 Valve housing [0127] 106 Valve receptacle [0128] 107 First bore
[0129] 108 Second bore [0130] 109 First surrounding construction
[0131] 110 Second surrounding construction [0132] 111 Axial stop
[0133] 112 Area reduced in outer diameter [0134] 113 Pressure
medium channel [0135] 114a First rising groove [0136] 114b Second
rising groove [0137] 114p Third rising groove [0138] 115a First
radial opening [0139] 115b Second radial opening [0140] 115p Third
radial opening [0141] 116a First ring groove [0142] 116b Second
ring groove [0143] 116p Third ring groove [0144] 117a First opening
[0145] 117b Second opening [0146] 117p Third opening [0147] 119
Push rod [0148] 120 First spring element [0149] 121 Control section
[0150] 122 Fourth ring groove [0151] 123 Fourth openings [0152] 124
Sealing element [0153] 125 Seal [0154] 126 First area [0155] 127
Second area [0156] 128 Transition area [0157] 129 First conical
area [0158] 130 Ring edge [0159] 131 Second conical area [0160] 132
Hollow space [0161] 133 Inner casing surface [0162] 134 Outer
casing surface
* * * * *